Rel. RG10(BSS) Operating Documentation - Sept 2010

Nokia Siemens Networks GSM/EDGE BSS, rel. RG10(BSS), operating documentation, issue 05, doc change delivery 4

Flexi Multiradio BTS GSM/EDGE Feature Descriptions

DN0967559 Issue 01AApproval Date 2010-09-23

2DN0967559 Issue 01A


Id:0900d805807f605c

The information in this document is subject to change without notice and describes only the product defined in the introduction of this documentation. This documentation is intended for the use of Nokia Siemens Networks customers only for the purposes of the agreement under which the document is submitted, and no part of it may be used, reproduced, modified or transmitted in any form or means without the prior written permission of Nokia Siemens Networks. The documentation has been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using it. Nokia Siemens Networks welcomes customer comments as part of the process of continuous development and improvement of the documentation.

The information or statements given in this documentation concerning the suitability, capacity, or performance of the mentioned hardware or software products are given "as is" and all liability arising in connection with such hardware or software products shall be defined conclusively and finally in a separate agreement between Nokia Siemens Networks and the customer. However, Nokia Siemens Networks has made all reasonable efforts to ensure that the instructions contained in the document are adequate and free of material errors and omissions. Nokia Siemens Networks will, if deemed necessary by Nokia Siemens Networks, explain issues which may not be covered by the document.

Nokia Siemens Networks will correct errors in this documentation as soon as possible. IN NO EVENT WILL Nokia Siemens Networks BE LIABLE FOR ERRORS IN THIS DOCUMENTA-TION OR FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO SPECIAL, DIRECT, INDI-RECT, INCIDENTAL OR CONSEQUENTIAL OR ANY LOSSES, SUCH AS BUT NOT LIMITED TO LOSS OF PROFIT, REVENUE, BUSINESS INTERRUPTION, BUSINESS OPPORTUNITY OR DATA,THAT MAY ARISE FROM THE USE OF THIS DOCUMENT OR THE INFORMATION IN IT.

This documentation and the product it describes are considered protected by copyrights and other intellectual property rights according to the applicable laws.

The wave logo is a trademark of Nokia Siemens Networks Oy. Nokia is a registered trademark of Nokia Corporation. Siemens is a registered trademark of Siemens AG.

Other product names mentioned in this document may be trademarks of their respective owners, and they are mentioned for identification purposes only.

Copyright © Nokia Siemens Networks 2010. All rights reserved

f Important Notice on Product Safety Elevated voltages are inevitably present at specific points in this electrical equipment. Some of the parts may also have elevated operating temperatures.

Non-observance of these conditions and the safety instructions can result in personal injury or in property damage.

Therefore, only trained and qualified personnel may install and maintain the system.

The system complies with the standard EN 60950 / IEC 60950. All equipment connected has to comply with the applicable safety standards.

The same text in German:

Wichtiger Hinweis zur Produktsicherheit

In elektrischen Anlagen stehen zwangsläufig bestimmte Teile der Geräte unter Span-nung. Einige Teile können auch eine hohe Betriebstemperatur aufweisen.

Eine Nichtbeachtung dieser Situation und der Warnungshinweise kann zu Körperverlet-zungen und Sachschäden führen.

Deshalb wird vorausgesetzt, dass nur geschultes und qualifiziertes Personal die Anlagen installiert und wartet.

Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Angeschlossene Geräte müssen die zutreffenden Sicherheitsbestimmungen erfüllen.

DN0967559 Issue 01A3


Id:0900d805807f605c

Table of ContentsThis document has 102 pages.

1 Summary of changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 Overview of features in Flexi Multiradio BTS GSM/EDGE. . . . . . . . . . . 10

3 Data/Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1 BSS20088 Dual Transfer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.2 BSS9006 General Packet Radio Service (GPRS) . . . . . . . . . . . . . . . . . 123.3 BSS10083 Enhanced General Packet Radio Service (MCS-1 - MSC-9) 133.4 BSS7003 High Speed Circuit Switched Data and BSS7037 14.4 kbit/s Data

Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.5 BSS10004 Adaptive Multi Rate Codec (AMR). . . . . . . . . . . . . . . . . . . . 173.6 BSS7005 Intelligent Frequency Hopping and BSS6114 Intelligent Under-

lay-Overlay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.7 BSS20960 Wideband AMR and BSS21118 TFO for AMR . . . . . . . . . . 19

4 Interworking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.1 BSS10101 GSM-WCDMA Interworking. . . . . . . . . . . . . . . . . . . . . . . . . 204.2 BSS11086 Support for Enhanced Measurement Report . . . . . . . . . . . . 21

5 Operability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225.1 2G Flexi BTS Manager Compatibility Launcher. . . . . . . . . . . . . . . . . . . 225.2 BTS Trace Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245.3 Antenna VSWR measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.4 BSC download of Abis mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265.5 BSS20847 Automatic commissioning of the Flexi Multiradio BTS

GSM/EDGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275.6 BSS20817 End to End Downlink Abis Performance Monitor. . . . . . . . . 285.7 BSS20760 BTS ID shown in 2G Flexi BTS Site Manager . . . . . . . . . . . 295.8 BSS20063 Space Time Interference Rejection Combining . . . . . . . . . . 305.9 BSS20040 User Access Level Control (UALC) . . . . . . . . . . . . . . . . . . . 325.10 BSS11047 Intelligent shutdown for Flexi Multiradio BTS GSM/EDGE . 345.11 Remote mode of 2G Flexi BTS Site Manager . . . . . . . . . . . . . . . . . . . . 365.12 BSS10063 Rx Antenna Supervision by Comparing RSSI . . . . . . . . . . . 375.13 BSS9068 BTS SW management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395.14 BSS9058 BTS fault recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405.15 BSS9063 Abis loop test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415.16 BSS9062 BTS supervision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425.17 BSS9061 Temperature control system . . . . . . . . . . . . . . . . . . . . . . . . . 435.18 BSS9060 TRX Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445.19 TRX Loop Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465.20 BSS9059 BTS resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475.21 BTS Auto-detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485.21.1 BSS9056 Auto-detection of Site Configuration . . . . . . . . . . . . . . . . . . . 485.22 48 V DC input voltage supervision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.23 BSS20958 Energy saving mode for BCCH TRX . . . . . . . . . . . . . . . . . . 50

6 Site solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51



Id:0900d805807f605c

6.1 BSS10046 Multi BCF Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516.2 BSS9055 Clock Synchronisation between Base Stations . . . . . . . . . . . 526.3 1 Pulse Per Second (PPS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546.4 BSS10069 Synchronized BSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556.4.1 BSS20371 BSS Site Synchronisation Recovery Improvement. . . . . . . . 556.4.2 BSS11073 Recovery for BSS and Site Synchronisation . . . . . . . . . . . . 556.5 Operating bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576.6 BTS2043 BTS External Alarms and Controls (EAC) . . . . . . . . . . . . . . . 586.7 BTS2020 RX antenna diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596.8 BTS configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606.8.1 Antenna-optimized configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606.9 Flexi Multiradio BTS GSM/EDGE Feederless Site concept . . . . . . . . . . 616.9.1 Feederless site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7 Basic GSM operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637.1 BSS21113 Increased dynamic SDCCH capacity . . . . . . . . . . . . . . . . . . 637.2 BSS20872 Robust AMR signaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647.3 BSS20588 TRAU bicasting in AMR FR/HR handover . . . . . . . . . . . . . . 667.4 Basic GSM features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677.5 BSS6071 Enhanced Full Rate Codec. . . . . . . . . . . . . . . . . . . . . . . . . . . 687.6 BTS2023 Downlink and uplink DTX . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697.7 BTS2503 Compressed Abis timeslot allocation . . . . . . . . . . . . . . . . . . . 707.8 BTS2067 Fast Associated Control Channel (FACCH) Call Setup . . . . . 717.9 BSS7036 Dynamic SDCCH Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . 727.10 BTS2024 Synthesized frequency hopping . . . . . . . . . . . . . . . . . . . . . . . 737.11 BTS2013 Baseband Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . 747.12 BTS2037 Air interface measurement pre-processing . . . . . . . . . . . . . . . 757.13 BTS2012 BTS time base reference from PCM . . . . . . . . . . . . . . . . . . . . 767.14 BTS2133 Short Message Service (SMS) point-to-point . . . . . . . . . . . . . 777.15 BTS2033 Short message cell broadcast. . . . . . . . . . . . . . . . . . . . . . . . . 787.16 BSS6025 Short Message Service Cell Broadcast with Discontinuous Re-

ceiving (SMS-CB DRX). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797.17 BSS6083 Mobile Station (MS) speed detection . . . . . . . . . . . . . . . . . . . 807.18 BSS20093 A5/3 ciphering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 827.19 Multiple Operator BSS Configuration (MOBBS) . . . . . . . . . . . . . . . . . . . 83

8 Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858.1 Basic transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858.1.1 Abis Trunk Transmission for E1 (ETSI) interface . . . . . . . . . . . . . . . . . . 858.1.2 Abis Trunk Transmission Allocation for T1 (ANSI) Interface. . . . . . . . . . 868.1.3 Abis Trunk Signaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 878.1.4 Network Synchronisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 888.1.5 Transmission equipment management. . . . . . . . . . . . . . . . . . . . . . . . . . 898.1.6 Support for Microwave Radio Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908.1.7 BSS9065 Transmission Operability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918.1.8 BSS21234 Support for BTS PWE Counters at BSC/NetAct . . . . . . . . . . 928.1.9 BSS21290 Flexi Multiradio BTS Ethernet Switching. . . . . . . . . . . . . . . . 938.2 Transmission solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94



Id:0900d805807f605c

8.2.1 PDH traffic routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 948.2.2 BSS30280 Abis loop protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 958.2.3 Redundant Abis Trunk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 978.3 BSS30305 Flexi Multiradio BTS Abis over IP/Ethernet . . . . . . . . . . . . . 988.4 BSS10045 Dynamic Abis allocation. . . . . . . . . . . . . . . . . . . . . . . . . . . 1008.5 BSS5850 Satellite Abis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1018.6 BSS21497 Enhanced satellite support . . . . . . . . . . . . . . . . . . . . . . . . 102



Id:0900d805807f605c

List of FiguresFigure 1 Incremental Redundancy scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Figure 2 Typical data throughputs for 14.4 kbit/s (non-transparent) and 9.6 kbit/s

coding (this depends on the NW radio conditions) . . . . . . . . . . . . . . . . . 16Figure 3 Compatibility launcher-local connection . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 4 Compatibility launcher-connecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Figure 5 Compatibility launcher-Create File option . . . . . . . . . . . . . . . . . . . . . . . . 23Figure 6 2G Flexi BTS Site Manager connected in remote mode. . . . . . . . . . . . . 36Figure 7 TRX Test window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Figure 8 Multi BCF configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Figure 9 Synchronized BSS example in Flexi Multiradio BTS chain. . . . . . . . . . . 56Figure 10 Common BCCH configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Figure 11 Feederless rooftop site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Figure 12 TRAU bicasting in AMR FR/HR handover . . . . . . . . . . . . . . . . . . . . . . . 66Figure 13 Dynamic SDCCH allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72Figure 14 SMS-CB DRX Schedule Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Figure 15 MS speed detection used for handover decision . . . . . . . . . . . . . . . . . . 80Figure 16 Loop principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95Figure 17 PW network topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98



Id:0900d805807f605c

List of TablesTable 1 Peak data rates for single slot EGPRS . . . . . . . . . . . . . . . . . . . . . . . . 13Table 2 Corresponding maximum data rates with different channel coding . . . 15Table 3 Channel and speech codec modes for AMR . . . . . . . . . . . . . . . . . . . . 17Table 4 Antenna-optimized configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Table 5 2 sectors using same pipes configurations . . . . . . . . . . . . . . . . . . . . . . 83Table 6 Number of 16 kbps DAP sub channels used with each CS and MCS 100



Id:0900d805807f605c


Flexi Multiradio BTS GSM/EDGE Feature Descriptions Summary of changes

Id:0900d805807f6a73

1 Summary of changes Changes between issues 01A and 01Updated Section:

• BSS11047 Intelligent shutdown for Flexi Multiradio BTS GSM/EDGE (Chapter Operability)

10DN0967559 Issue 01A


Id:0900d8058076cffb

Overview of features in Flexi Multiradio BTS GSM/EDGE

2 Overview of features in Flexi Multiradio BTS GSM/EDGEOperating and Application SWNokia Siemens Networks RG10(BSS) Software consists of Operating Software and Application Software:

• Operating Software refers to basic functionalities of a product. • Application Software refers to optional features.

For more information on the features, see Nokia Siemens Networks GSM/EDGE BSS, rel. RG10(BSS), operating documentation.

For general guidelines related to licensing, see Licence Management in BSC in the GSM/EDGE BSS operating documentation.

DN0967559 Issue 01A11

Flexi Multiradio BTS GSM/EDGE Feature Descriptions Data/Voice

Id:0900d8058076d01f

3 Data/Voice

3.1 BSS20088 Dual Transfer ModeDual Transfer Mode (DTM) provides mobile users with simultaneous circuit-switched (CS) voice and packet-switched (PS) data services. This means that users can, for example, send and receive e-mail during an ongoing phone call.

In dual transfer mode, the mobile station (MS) is simultaneously in dedicated mode and in packet transfer mode, so that the timeslots allocated for each MS are consecutive and within the same frequency.

BenefitsWith DTM, the operator can expand the service portfolio to offer users enhanced services in a GSM/EDGE network. DTM allows the operator to provide a wide range of services that demand a simultaneous CS and PS connection. Mobile users can use data services, such as file transfer, web browsing, video sharing, and mobile net meeting, during a speech call. This makes it possible to launch services similar to UMTS class A services also in 2G networks. In addition, these services can be used to complement the 3G coverage in places where there is no 3G network coverage.

BTS functionality supportThe BTS supports DTM through the normal BTS support of CS and PS services.

Interaction with other featuresDTM supports all full rate speech codecs. The CS speech codec selection for DTM is similar to the selection mechanism used for a plain CS connection. In addition, the DTM PS channels can be multiplexed in a similar way to normal GPRS/EDGE.

12DN0967559 Issue 01A


Id:0900d8058076d00d

3.2 BSS9006 General Packet Radio Service (GPRS)General Packet Radio Service GPRS provides packet radio access for GSM mobile sta-tions.

By sharing the channels provided by various network elements and transmission systems, the cellular network resources are used more efficiently for data services than with circuit switched data services.

All mobile stations share the radio resources in a cell, and use the radio resources only when sending or receiving data.

The Channel Coding Unit (CCU) in the BTS performs the channel coding for the follow-ing ETSI defined coding schemes:

• Channel Coding Scheme 1 (CS1) 9.05 kbit/s • Channel Coding Scheme 2 (CS2) 13.4 kbit/s • Channel Coding Scheme 3 (CS3) 15.6 kbit/s • Channel Coding Scheme 4 (CS4) 21.4 kbit/s

In packet transfer mode, the mobile station must use the continuous timing advance pro-cedure. This procedure is carried out on all packet data channels (PDCHs).

Coding Schemes CS3 and CS4 (BSS11088) is an application software product, and it requires a valid licence in the BSC. CS3 and CS4 provide a considerable gain in data rates for GPRS mobile stations not supporting EGPRS (the mandatory RLC header octets are excluded from the data rate values).

Link Adaptation (LA)Flexi Multiradio BTS GSM/EDGE supports PCU with GPRS link adaption by providing the measurements for the uplink radio blocks.

Interaction with other featuresCS3 and CS4 do not fit to one 16kbit/s Abis/PCU channel and require the use of Dynamic Abis Allocation.

DN0967559 Issue 01A13


Id:0900d8058076d010

3.3 BSS10083 Enhanced General Packet Radio Service (MCS-1 - MSC-9)Enhanced General Packet Radio Service (EGPRS) supports high rate packet data services across varying channel conditions. EGPRS is built on top of the packet switched data service, GPRS. As the table below shows, EGPRS supports higher data rates compared to the basic GPRS, using several Modulation and Coding Schemes (MCSs). The speed in radio resources is fixed for Gaussian Minimum Shift Keying (GMSK) and 8 Phase Shift Keying (8PSK), but because the amount of channel coding varies, the user data rate varies depending on the MCS.

GMSK modulation provides the robust mode for wide area coverage, while 8PSK provides higher data rates.

The MCSs are organized into families to allow a re-segmentation of the data block for link adaptation. Since higher protection means lower throughput, the protection that best fits the channel condition is chosen for maximum throughput.

Incremental Redundancy (IR)Incremental Redundancy (IR) is an efficient combination of two techniques: Automatic Repeat ReQuest (ARQ) and Forward Error Correction (FEC). In the ARQ method, when the receiver detects the presence of errors in a received data block, it requests a re-transmission of the same data block from the transmitter. The process continues until an uncorrupted copy reaches the destination. The FEC method adds redundant infor-mation to the user information at the transmitter, and the receiver uses the information to correct errors caused by disturbances in the radio channel.

In the IR scheme (also known as Type II Hybrid ARQ scheme), only a small amount of redundancy is sent first, which yields a high user throughput if the decoding is success-ful. However, if the decoding fails, a re-transmission takes place according to the ARQ method. Using IR, the re-transmission of the data block is different from the initial trans-mission. The transmitter sends additional redundancy that is decoded at the destination with the previously received information to allow for error correction. Since the combina-tion includes more information than any individual transmission, the probability of correct reception is increased.

MCS Modulation Code Rate Family User Rate

MCS-1 GMSK .53 C 8.8 kbps

MCS-2 GMSK .66 B 11.2 kbps

MCS-3 GMSK .80 A 14.8 kbps

MCS-4 GMSK 1 C 17.6 kbps

MCS-5 8PSK .37 B 22.4 kbps

MCS-6 8PSK .49 A 29.6 kbps

MCS-7 8PSK .75 B 44.8 kbps

MCS-8 8PSK .92 A 54.4 kbps

MCS-9 8PSK 1 A 59.2 kbps

Table 1 Peak data rates for single slot EGPRS

14DN0967559 Issue 01A


Id:0900d8058076d010

The IR mechanism in EGPRS is designed around nine Modulation and Coding Schemes (MCSs). The basic characteristics of each MCS are its fixed data rate and fixed protection level. For each of the MCSs, it is possible to reach the same data rate with the same protection level, but with a different protection scheme.

Figure 1 Incremental Redundancy scheme

There are three protection schemes (P1, P2 and P3) for an MCS, as shown in the figure above. The data block is first protected with the P1 of a certain MCS, and sent over the air to the receiver, which tries to recover the data. If this phase fails, the received P1 is stored in the receiver's memory for future use, and the transmitter sends the data block protected with the P2 of the same MCS. The receiver combines the received P2 with the stored P1 and tries to recover the data from the combination of P1 and P2. This process continues until the data is recovered.

If after P3, the data still cannot be recovered, P1 is sent again and combined with the stored P1, P2 and P3 (which reaches a protection level of about four times P1), and so on until the data is recovered.

Link Adaptation (LA)Flexi Multiradio BTS supports PCU with EGPRS link adaption by providing the measure-ments for the uplink radio blocks.

Interaction with other featuresEGPRS Modulation and Coding Schemes MCS-1 - MCS-9 require the use of Dynamic Abis Allocation.

Data Block

One MCS

P2 P3P1

P2

P2

P2

P1

P1

P1

P1

Stored

Stored

Receiver

Transmitter

No data

recovered

No data

recoveredCombination: Protection Level x 2

Protection Level 1

Combination: Protection Level x 3

Stored

P3

P3

1st transmission 1st re-transmissionupon reception failure

2nd re-transmissionupon reception failure

DN0967559 Issue 01A15


Id:0900d80580778d89

3.4 BSS7003 High Speed Circuit Switched Data and BSS7037 14.4 kbit/s Data ServicesHigh Speed Circuit Switched Data uses multiple parallel channels to provide higher data rates for end-user applications, such as the World Wide Web, file transfer and facsimile.

The BSS implementation is to reserve a multiple set of basic resources for one high speed data call. The data rate and the number of reserved timeslots vary between one and the defined maximum of the user application. The variable rate is needed for various common procedures, for example for handovers to a new cell if the requested data rate cannot be given immediately. The BSS implementation of HSCSD supports the simul-taneous usage of a maximum of four radio timeslots (RTSLs) per HSCSD call.

The table below presents the corresponding maximum data rates with different channel coding.

Both asynchronous and synchronous bearer services and transparent and non-trans-parent data services are supported. Transparent HSCSD uses fixed data rate through-out the duration of the call, but with non-transparent HSCSD, the data rate can be changed automatically during the call, because of increased traffic for example. The radio interface is either symmetric or asymmetric according to the mobile station (MS) capability.

During basic channel allocation, the system tries to keep consecutive timeslots free for multichannel HSCSD connection. If there are not enough appropriate free channels to fulfill the requested data rate, a non-transparent HSCSD connection is started with fewer channels than requested. At least one channel is allocated for a non-transparent HSCSD call request if there are available resources in the cell. By use of the resource upgrade procedure, the data rate of the HSCSD connection can be increased when an appropriate channel is available.

In a congested cell, the HSCSD load can be adjusted by BSC parameterization. The resource downgrade procedure is used to lower the HSCSD connection data rate to release radio channels for other connections. If a transparent connection cannot be established in a cell, a directed retry can be attempted.

BSS7037 14.4 kbit/s GSM Data ServicesWith the 14.4 kbit/s GSM Data Services, the speed of one timeslot increases from 9.6 kbit/s to 14.4kbit/s.

The 14.4 kbit/s channel coding has less error correction than 9.6 kbit/s coding. There-fore, there are some areas on the cell edges where using 9.6 kbit/s coding will give a higher data throughput. The figure below shows the results of Nokia Siemens Networks simulations. Note that for transparent mode the maximum user throughput is 14.4 kbit/s, but in non-transparent mode, the maximum user throughput is 13.2 kbit/s. The

Number of RTSLs 9.6 kbit/s 14.4 kbit/s

1 9.6 kbit/s 14.4 kbit/s




Table 2 Corresponding maximum data rates with different channel coding

16DN0967559 Issue 01A


Id:0900d80580778d89

maximum throughput is based on the amount of available space in the coding block. Non-transparent data requires space for error checking, but transparent data does not.

Figure 2 Typical data throughputs for 14.4 kbit/s (non-transparent) and 9.6 kbit/s coding (this depends on the NW radio conditions)

The Automatic Link Adaptation (ALA) optimizes the data throughput by automatically choosing the channel coding most suitable to the radio conditions and by control of the power levels.

The 14.4 kbit/s Data Services can be combined with High Speed Circuit Switched Data (BSS7003).

Note that Flexi Multiradio BTS does not support transparent data handovers because of limitations in fax protocols.

0

2

4

6

8

10

12

14

60 65 70 75 80 85 90 95 100

Percentage of Cell Area (%)

Da

taT

hro

ug

hp

ut

Ra

te(k

bit/s

)

14.4

9.6

DN0967559 Issue 01A17


Id:0900d8058076d016

3.5 BSS10004 Adaptive Multi Rate Codec (AMR)Adaptive Multi Rate Codec provides significantly better speech quality by:

• using better source coding algorithms that give better subjective speech quality for the same link capacity

• adaptively adjusting ratio of bits used for speech coding and channel coding to always provide best subjective speech quality according to current radio conditions.

With AMR it is possible to increase speech capacity by using HR mode and still maintain the quality of current FR calls. It consists of an adaptive algorithm for codec changes and 8 different speech codecs (14 codec modes) listed in the table below.

Codec mode adaptation for AMR is based on received channel quality estimation in both the mobile station (MS) and the BTS.

The BTS and MS inform and request of codec used/to be used by in-band signaling.

Channel mode

Channel codec mode

Source coding bit-rate, speech

Net bit-rate, in-band channel

Channel coding bit-rate, speech

Channel coding bit-rate, in-band

TCH/FR CH0-FS

CH1-FS

CH2-FS

CH3-FS

CH4-FS

CH5-FS

CH6-FS

CH7-FS

12.20 kbit/s (GSMEFR)

10.20 kbit/s

7.95 kbit/s

7.40 kbit/s (IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

10.20 kbit/s

12.20 kbit/s

14.45 kbit/s

15.00 kbit/s

15.70 kbit/s

16.50 kbit/s

17.25 kbit/s

17.65 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

TCH/HR CH8-HS

CH9-HS

CH10-HS

CH11-HS

CH12-HS

CH13-HS

7.95 kbit/s (*)

7.40 kbit/s (IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

3.25 kbit/s

3.80 kbit/s

4.50 kbit/s

5.30 kbit/s

6.05 kbit/s

6.45 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

(*) Not supported, requires 16 kbit/s TRAU.

Table 3 Channel and speech codec modes for AMR

18DN0967559 Issue 01A


Id:0900d8058076d019

3.6 BSS7005 Intelligent Frequency Hopping and BSS6114 Intelligent Underlay-OverlayWith Intelligent Frequency Hopping and Intelligent Underlay-Overlay, it is possible to reuse frequencies more intensively, and therefore achieve a higher radio network capacity. With Intelligent Frequency Hopping, it is also possible to avoid frequency dependent fading on the radio path.

When Intelligent Frequency Hopping is in use, the operator can use Intelligent Underlay-Overlay simultaneously with frequency hopping in the same cell. Either baseband (BB) or radio frequency (RF) hopping can be used.

The different interference characteristics of the regular and super-reuse layers in Intel-ligent Underlay-Overlay require that the network plan for frequency hopping is con-structed separately for each layer. Intelligent Frequency Hopping enables the use of separate Mobile Allocation Frequency Lists of radio frequency hopping for the layers of an Intelligent Underlay-Overlay cell. Baseband hopping is implemented by treating the regular layer as a normal cell and the super-reuse layer as a new hopping group.

The operator can set the regular and super-reuse layers in Intelligent Underlay-Overlay individually to hopping.

DN0967559 Issue 01A19


Id:0900d8058076d01c

3.7 BSS20960 Wideband AMR and BSS21118 TFO for AMRThese features introduce wideband AMR coding as specified by 3GPP and ITU-T. Wideband AMR is based on a family of new speech codecs. It is designed to achieve improvements in speech quality. The sampling rate of WB AMR speech codec is increased to 16 kHz which allows the bandwidth of the signal encoded to be extended to cover range from 50 to 7000 Hz. Wideband AMR requires end to end tandem free operation support.

20DN0967559 Issue 01A


Id:0900d8058076d027

Interworking

4 Interworking

4.1 BSS10101 GSM-WCDMA InterworkingIn order for an operator to provide seamless coverage in areas where WCDMA is not available, such as rural areas, inter-system handovers are introduced. This feature facil-itates handovers between GSM BSS and WCDMA RAN. When the WCDMA and GSM networks overlap, also an inter-system handover from GSM to WCDMA can be made to release traffic load in the GSM system.

Flexi Multiradio BTS supports this feature as a GSM EDGE Base Station.

DN0967559 Issue 01A21


Id:0900d8058076d024

4.2 BSS11086 Support for Enhanced Measurement ReportSupport for Enhanced Measurement Report (EMR) provides the system with enhanced serving and neighbor cell measurements. This is achieved by requesting the mobile station (MS) to use the EMR for reporting downlink measurements.

Enhanced Measurement Report also provides the system with information such as Downlink Frame Erasure Rate (DL FER), the usage of bit error probability (BEP) instead of RX Quality during the DTX frames, and the support for reporting WCDMA RAN neighbor cells. In addition, the EMR also provides an extended range for the serving and neighbor cells downlink signal strength and the possibility to report altogether up to 15 GSM and/or WCDMA RAN neighbor cells in one report.

These reports can be used by the network to enhance the generic performance of the existing system, enable GSM/WCDMA interworking, and enhance several features, such as:

• Automated Planning • FER Measurement • Intelligent Underlay Overlay (IUO) and Intelligent Frequency Hopping (IFH)

Interaction with other features:

• The network does not order an MS to use the EMR for reporting when an Idle Broad-cast Control Channel (BCCH) Allocation List or a Measurement BCCH Allocation List is used in active state in the serving cell.

• With Common BCCH Control, when a call is in a non-BCCH frequency band, the serving cell BCCH frequency is added to the BCCH frequency list.

• When the EMR is used for reporting, also the serving cell BSIC is added to the BSIC list before sending it to an MS.

Benefits

• Improved generic performance of the system • Enables GSM/EDGE/WCDMA interworking • Improved performance of statistics

22DN0967559 Issue 01A


Id:0900d805807f6083

Operability

5 Operability

5.1 2G Flexi BTS Manager Compatibility LauncherThe Compatibility Launcher communicates with the BTS and with the installed 2G Flexi BTS Site Managers. It requests for parameters such as BTS SW version, Management interface version, and BTS type from the BTS and also fetches the SW version and Man-agement interface version from the installed 2G Flexi BTS Site Managers. Based on the values of these parameters, the Compatibility Launcher launches the appropriate 2G Flexi BTS Site Manager.

The following functionalities are supported in the Compatibility Launcher:

• Local connection with BTS • Remote connection with BTS • Create SCF file in offline mode for commissioning • Display help for Flexi EDGE and Flexi Multiradio BTS

The following screenshot shows the Compatibility Launcher:

Figure 3 Compatibility launcher-local connection

The following screenshot shows the Compatibility Launcher when it is trying to connect to the BTS.

DN0967559 Issue 01A23

Flexi Multiradio BTS GSM/EDGE Feature Descriptions Operability

Id:0900d805807f6083

Figure 4 Compatibility launcher-connecting

In the Create File option, the user can select the desired 2G Flexi BTS Site Manager version to create the SCF file in offline mode.

Figure 5 Compatibility launcher-Create File option

24DN0967559 Issue 01A


Id:0900d8058076d029

5.2 BTS Trace ToolBTS Trace Tool is built in the 2G Flexi BTS Site Manager application and can be used to collect detailed logs when investigating a problem seen on a customer BTS site. The tool can be controlled either via local or remote 2G Flexi BTS Site Manager minimizing the need for site visits. The tool provides the functionality to collect logs remotely from the BTS site over the Abis link. In addition to a few standard logs, custom logs can be recorded as well with the help of custom trace set files provided by the NSN customer support team. The recorded log files can be decoded and analyzed by NSN.

DN0967559 Issue 01A25


Id:0900d8058076d02c

5.3 Antenna VSWR measurementFlexi Multiradio BTS provides antenna line supervision by means of voltage standing wave ratio (VSWR) monitoring in the RF Module (FXxx). During commissioning, the user can set the VSWR minor (7607) and major (7606) alarm limits for each antenna line sep-arately. The minor limit can be set between 1.5 to 2.9:1 (that is, with a return loss 14.0 - 6.2 dB) and the major limit between 2.7 to 3.5:1 (6.8 - 5.1 dB). The default limits on the 2G Flexi BTS Site Manager are 2.1:1 (minor) and 3.1:1 (major) which convert to 9 dB (minor) and 5.8 dB (major) return loss (RL) respectively. At the end of the commissioning process, the values are stored in the site configuration file (SCF) in the System Module's (ESMB/C) non-volatile memory. During normal BTS operation, the System Module (ESMB/C) sends a polling request to the RF Module (FXxx) every few seconds. The RF Module (FXxx) responds with a message containing the return loss values for both antenna paths (A and B). The RF Module (FXxx) can report the return loss reliably if the TX power in its TxA or TxB input exceeds approximately +32 dBm. The BTS software converts the reported return loss values to VSWR values, and compares them with the minor and major limits found in the site configuration file. If the reported VSWR exceeds the minor limit, alarm 7607 'TRX operation degraded' is activated. If the reported VSWR exceeds the major limit, alarm 7606 'TRX faulty' is activated, and the affected TRX objects are blocked.

Typical causes for a bad VSWR are broken cables, broken connectors, and the ingress of water in the antenna cable path.

26DN0967559 Issue 01A


Id:0900d8058076d02f

5.4 BSC download of Abis mappingAbis mapping automates the process of providing Abis allocations on the BTS. The BTS is able to configure the allocation of the Abis using the information received from the BSC, instead of BTS gets information from a Site Configuration File (SCF). This config-uration is performed by the BTS, by using mapping algorithms to convert BSC data into BTS Abis allocations. The mapping between the BSC data and the interfaces at the BTS relies on reference signals that are collectively known as the Abis Termination informa-tion of the BTS. The Abis mapping information is provided to the BTS. The Abis Termi-nation information is provided to the BTS during commissioning via SCF from the 2G Flexi BTS Site Manager. One reference signal per interface is supported at the BTS.

An Abis mapping Information Element (IE) consists of Abis channels (TRXSIG and TCH) in BTS_CONF_DATA grouped into a bundle. The BTS_CONF_DATA can carry several instances of Abis mapping IE(s), one for each bundle or interface. The interface time slots in the Abis mapping IE(s) from the BSC are the time slots at the BSC interface. OMUSIG configuration is still taken from the Abis Termination information already stored at the BTS, and not from the Abis mapping IE. The timeslot information provided in the Abis mapping IE is converted into timeslot information for the BTS via the Abis mapping algorithm. EDAP information is provided using the Dynamic Pool Info IE(s) in the BTS_CONF_DATA. The interface time slots in the Dynamic Pool Info IE(s) are the time slots at the BSC interface. At the BTS, one bundle per interface is supported, and, at the BSC, multiple bundles per interface are supported. However, one bundle cannot include multiple interfaces.

The 2G Flexi BTS Site Manager supports Abis mapping download function:

• A BSC Abis Mapping Status view menu item has been added in the Transmission menu of the 2G Flexi BTS Site Manager. • The BSC Abis mapping facilitates the user to view the differences and conflicts

in the BSC and BTS allocations for a selected interface or a BSC bundle. The user can select an interface from the list of interfaces displayed in the Transmission equipment view or select a BSC bundle from an available list of bundles. As per user selection, the details of the BTS interface, reference signal and the calculated offset value are displayed.

• This is only available in online mode. • Two check boxes have been added for the BSC Abis mapping download function in

the Abis Termination screen of the Commissioning Wizard: • Enable Abis Signal Mapping allows the user to enable/disable the Abis signal

mapping. • Allow Abis Allocations from 2G Flexi BTS Site Manager allows the user to

enable/disable the Abis allocations from the 2G Flexi BTS Site Manager. If this check box is selected and the user enters the Abis allocations from the 2G Flexi BTS Site Manager, they might later be overwritten by the allocation data from the BSC.

• These options are available in both online and offline mode.

DN0967559 Issue 01A27


Id:0900d8058076d032

5.5 BSS20847 Automatic commissioning of the Flexi Multira-dio BTS GSM/EDGEFlexi Multiradio BTS GSM/EDGE is designed so that it is easy to install and commission. Easy commissioning needs support also from the BSC. The following functions are related to the automatic commissioning of the Flexi Multiradio BTS GSM/EDGE:

• The BSC must be able to download Abis mapping to the BTS as Abis mapping allows the BSC to dynamically provide the Abis allocations (TRXSIG, TCH, and EDAP) for a BTS. The BTS configures the Abis allocations of the TRXSIGs, TCHs, and EDAPs using the information received from the BSC, instead of getting the infor-mation in the SCF. The mapping between the BSC data and the interfaces at the BTS relies on reference signals (one per interface (E1/T1) at the BTS) which are col-lectively known as the Abis termination information of the BTS. The Abis termination information is provided to the BTS during commissioning via SCF from the 2G Flexi BTS Site Manager.

• When the site is commissioned, the BSC must automatically unlock the BCF when the BTS informs that it is ready.The 'Auto unlock allowed' is a configurable functionality (a BCF-level parameter in the BSC).

28DN0967559 Issue 01A


Id:0900d8058076d035

5.6 BSS20817 End to End Downlink Abis Performance Monitor BSS20065, in BSC S11.5 SW, implements counters in the BSC that check the uplink signaling channels (channels using LAPD), keeps the results in a set of counters, and every 24 hours checks the number of errors (CRC errors) against an alarm threshold.

BSS20817 is an equivalent feature for the Downlink Abis.

The BTS keeps downlink counters for each LAPD connection that terminates in the BTS. The counters measure the number of received bytes, the number of CRC errors and the number of T200 timeouts. The BTS reports the counter numbers, per channel, every hour between 10 minutes before the hour and the top of the hour according to the BTS real-time clock.

DN0967559 Issue 01A29


Id:0900d8058076d038

5.7 BSS20760 BTS ID shown in 2G Flexi BTS Site ManagerAt present, the 2G Flexi BTS Site Manager shows "Sector" number for each Sector, but the BSC shows "BTS" number. The "BTS" number can be different from the "Sector" number. With this feature the 2G Flexi BTS Site Manager will show both "Sector" number and "BTS" number, to avoid any confusion between an operator using 2G Flexi BTS Site Manager and an operator using the BSC MML or NetAct. The mapping between the "Sector" number and the "BTS" number is as sent in the Abis O&M interface in the BTS_CONF_DATA message.

30DN0967559 Issue 01A


Id:0900d8058076d03b

5.8 BSS20063 Space Time Interference Rejection CombiningThe Space Time Interference Rejection Combining (STIRC) is a licence-based applica-tion software in the BSC that enables/disables the use of STIRC technology in the BTS.

The STIRC is an uplink (UL) receiver performance enhancement to the Interference Rejection Combining (IRC) technology. When enabled, the STIRC technology is deployed in the UL by BTS. When disabled, the current IRC technology is deployed by the BTS.

The new technology improves the spectral efficiency of the network via link performance enhancement that significantly improves the interference (co-channel and adjacent channel) rejection capability of Flexi Multiradio BTS in the uplink direction. For example, the improved link level interference rejection performance of the STIRC with GMSK modulation will give on average a gain of 4 to 9 dB for co-channel interference compared to the IRC in 2-way Uplink Diversity (2UD) configurations. In addition, the current GMSK normal burst receiver sensitivity levels are not affected.

The STIRC can also help to maintain the link balance (UL and DL) needed with the deployment of Single Antenna Interference Cancellation (SAIC) technology in mobiles that improves interference cancellation capabilities in the downlink (DL).

The STIRC licensing software will be operational once the STIRC option is enabled at the BSC. The BSC will allocate the STIRC license from its available pool and send the STIRC option in the BTS_CONF_DATA to the BTS.

This feature affects alarm handling so that STIRC alarms can be cancelled without reset.

ImplementationThe STIRC feature can be enabled or disabled for the site any time the BTS is running because it does not require locking the sector or TRX. The BSC will send the STIRC option for each sector in the BTS_CONF_DATA. When receiving this option, the BTS O&M SW checks for each TRX in the sector for which STIRC is enabled, whether the HW configuration is valid for the STIRC feature. If an invalid configuration is used, an alarm is raised on the specific TRX(s) and these specific TRX(s) are blocked, and STIRC is enabled on rest of the TRX(s). BTS O&M SW enables the STIRC algorithm by informing the DSP of each valid TRX in the sector.

Note that the STIRC algorithm implementation requires 32-bit precision numerical cal-culations to minimize quantization errors, while for the IRC algorithm 16-bit precision is sufficient. Thus, for STIRC implementation 32-bit precision is used for all the functions, some of which are common to the IRC algorithm also. As a result of this, slight gain (up to 0.2 dB) in CCI and ACI performance can be observed even when the IRC algorithm is used (STIRC=N).

In order to achieve the STIRC gain, Rx Diversity should be in use (RDIV=Y).

RequirementsThis feature is supported by the following BTS generations and SW:

• Flexi EDGE EP2 • UltraSite CX5 with EDGE TRXs (BB2E/BB2F and TSxB) and Hybrid TRX

(BB2E/BB2F and TSxA). • MetroSite CXM5 with EDGE TRXs • BSC S12 • EX3.1 Flexi Multiradio

DN0967559 Issue 01A31


Id:0900d8058076d03b

Interaction with other features

• All valid hopping combinations for the supported TRX types are supported. • BSS synchronisation helps in achieving full STIRC gain.

BenefitsThe STIRC diversity algorithm improves the interference rejection performance and thus the overall network spectral efficiency and quality.

The STIRC ensures better uplink quality, particularly in high user density/interference limited scenarios, and better average user data throughput, as well as improved traffic and control channel performance. It also provides a possibility to use less mobile Tx power for quality-based uplink power control, which leads to reduction in the overall interference level in uplink and improves the mobile battery life.

32DN0967559 Issue 01A


Id:0900d8058076d03e

5.9 BSS20040 User Access Level Control (UALC)The User Access Level Control (UALC) is a solution to prevent unauthorized users from making changes that can affect the remote management and traffic. The UALC is for a remote connection only, in a local connection it is not in use.

The UALC defines two levels of access rights for the users of 2G Flexi BTS Site Manager:

• Full Access (Read and Write) means that all the functions that the manager applica-tions offer are available to the user.

• Limited Access (Read only) allows only to read information from an element.

Assignment of user rights is via the existing Windows user management processes. The 2G Flexi BTS Site Manager applications can start-up and operate independently regard-less of the Windows User Administration.

The 2G Flexi BTS Site Manager applications check if the User Access Level Control is enabled or disabled by reading the registry key 'Access Levels' under KEY_LOCAL_MACHINE/Software/Nokia Siemens Networks/2G Flexi BTS Site Manager:

• 'ON' – UALC is enabled. • 'OFF' – UALC is disabled.

If the UALC is disabled, the application gives Full Access Rights (both Read and Write) to the user. If the registry key is not present, by default Full Access Rights are granted.

In case the UALC is 'ON', that is, enabled, the EM application checks if the user currently logged in belongs to the BTS_Administrator group or not. If yes, the user is given Full Access Rights (both Read and Write). Otherwise, Limited Access Rights (Read only) are granted. If the BTS_Administrator group is not present on the PC/domain, by default Limited Access Rights are granted.

In case 2G Flexi BTS Site Manager is installed and the BTS_Administrator group does not exist on the PC, the user can create the group either using a SiteWizard installer or manually.

Creating the BTS_Admins user group manuallyTo create the BTS_Admins user group manually, follow the instructions below. Add the PC's login ID to the BTS_Admins group using the Control panel.

1. Go to Control Panel > User Accounts.2. Click on the Advanced tab and then the Advanced button. A new window Local

users and groups is displayed.3. Select a group and then create a new group 'BTS_Admins' by right-clicking on RHS.4. Select the newly created group, right-click the Add to group option, and then click

Add. The Select Users, Computers, or Groups window is displayed.5. Enter your PC login ID to the 'Enter the object names to select' and click OK.

Creating the User Access Level Key manuallyTo create the Access Levels key manually, follow the instructions below.

Registry location: KEY_LOCAL_MACHINE/Software/Nokia Siemens Networks/2G Flexi BTS Site Manager

Access Level Key name: Access Levels

Value: ON

DN0967559 Issue 01A33


Id:0900d8058076d03e

1. Open the Command Window, type regedit, and press Enter to open the 'Registry Editor'.

2. Go to HKEY_LOCAL_MACHINE/Software.3. Create a 'Nokia Siemens Networks' Key by right-clicking on Software > New > Key,

if not present.4. Create a '2G Flexi BTS Site Manager' Key by right-clicking on Nokia Siemens

Networks > New > Key, if not present.5. Create 'Access Levels' string values by right-clicking on 2G Flexi BTS Site Manager

> New > String Values.6. Modify the value of 'Access Levels' by right-clicking on Access Levels > Modify.

Type ON in the value data and press Ok.

34DN0967559 Issue 01A


Id:0900d805807f605d

5.10 BSS11047 Intelligent shutdown for Flexi Multiradio BTS GSM/EDGETo provide protection against a mains power break, the operator can equip a BTS with a battery backup system. The “Intelligent shutdown” feature is controlled by the BSC and its purpose is to maintain the BTS site operation for as long as possible by reducing capacity so that only the essential site functions are maintained.

When a mains breakdown takes place, then BTS sends an alarm to the BSC, which performs forced handovers for all the calls on the TRXs to be shut down. The calls are handed over to a TRX, which will remain powered, or to adjacent cells and finally the BSC orders the BTS site to stop transmission for the TRXs involved. When the main power is restored the BSC takes the BTS automatically back in full service.

On a BTS site basis, the user can define the service level of the site to be maintained while the battery backup is in use. Also, two timers can be defined, allowing the execu-tion of the shutdown procedure in phases, reducing capacity in a controlled way. Three service level options are available:

• Full service – Service is maintained at full capacity for as long as the battery power supply lasts. The two timers are ignored.

• Broadcast control channel (BCCH) backup – The BTS maintains full capacity until the first timer expires. After that, all active calls on non-BCCH transceivers are handed off. The non-BCCH transceivers are blocked from carrying any new calls and the BSC commands the BTS to shut them down. The BCCH TRX(s) are main-tained to offer minimum service.

• Transmission backup – The second timer starts after the first one has expired. After the expiry of the second timer, all active calls on BCCH transceivers are handed over. The BCCH transceivers are blocked from carrying new calls and the BSC commands the BTS to shut them down. Only the BTS transmission equipment power is maintained to secure the functionality of a transmission chain for as long as the batteries last.

When the mains power is restored, the BSC commands the BTS site to power all the shut down equipment and return back to full service.

Battery backup configurations for Flexi Multiradio BTS GSM/EDGE:

• Flexi with Multi Integrated Battery Backup Unit (MIBBU) • Flexi with Integrated Battery Backup Units • 3rd Party Battery Backup Solution

The optional battery backup system for the Flexi Multiradio BTS GSM/EDGE is selected in the 2G Flexi BTS Site Manager during the commissioning phase.

If 3rd party BBU solution is used, one external alarm (EAC) line needs to be designated to indicate a mains power loss/restoration from the BBU. The selected EAC line needs to be configured as a Mains alarm at the BSC. If BBU solution (FPxA, MIBBU or FPRx) is used, the FPA connector on the ESMB/C System Module can be used with no need to use nor configure any EAC lines. Note that if an EAC line is configured as a Mains alarm at the BSC, the BTS ignores the FPA connector.

With all BBU solution options, the BTS generates alarm 7995 Mains Breakdown when the BBU indicates mains power loss. The 7995 alarm then triggers the Intelligent Shutdown procedure at the BSC. If two or three phase supply is used with MIBBU or FPRx, the loss of one phase already generates the 7995 alarm.

DN0967559 Issue 01A35


Id:0900d805807f605d

In addition to alarm 7995, the FPA interface can also generate three other BBU-related alarms 7612/7613/7614 (note that with FPMA, only 7995 and 7613 alarms can be seen).

BenefitsThe operation is optimal during both short and long mains breaks. Timers allow execut-ing the shutdown procedure in several phases. Each phase reduces the battery power consumption.

With intelligent shutdown, the operator can define the service level to be applied on a mains failure to optimize the trade-off between the service level and battery power life-time. A short mains break will not reduce the service unnecessarily, whereas during a longer break, the essential functions, such as BCCH or transmission chain, are main-tained for as long as possible.

36DN0967559 Issue 01A


Id:0900d8058076d044

5.11 Remote mode of 2G Flexi BTS Site Manager The user can control Flexi Multiradio BTS equipment locally via 2G Flexi BTS Site Manager. To minimize the need for site visits, 2G Flexi BTS Site Manager functions can also be accessed remotely.

The user can monitor and test the BTS remotely, by connecting the 2G Flexi BTS Site Manager to the BTS remotely via NetAct™. A PC with the 2G Flexi BTS Site Manager software is used as a user terminal.

Figure 6 2G Flexi BTS Site Manager connected in remote mode

The user can connect to a remote BTS using the 2G Flexi BTS Site Manager application, via a menu item and/or a toolbar button, or via the command line. The user interface of 2G Flexi BTS Site Manager informs the user of the remote connection status when infor-mation is being requested from the remote BTS, and when the 2G Flexi BTS Site Manager is processing received information from a remote BTS. 2G Flexi BTS Site Manager connected in remote mode supports all features available via a local connec-tion, except the Control Abis interface (enable/disable) commands.

It is not possible to perform the initial BTS commissioning remotely, but it is possible to perform subsequent recommissioning or append commissioning from the 2G Flexi BTS Site Manager in remote mode.

At the BTS, the messages sent from or to the 2G Flexi BTS Site Manager in remote mode are re-routed, but handled in the same way as with the local connection.

The alarm 7801 MMI CONNECTED TO BASE STATION indicates whether the 2G Flexi BTS Site Manager is connected to the BTS locally (alarm text Local MMI connected) or remotely from NetAct (alarm text Remote MMI connected).

DN0967559 Issue 01A37


Id:0900d8058076d047

5.12 BSS10063 Rx Antenna Supervision by Comparing RSSIThe purpose of Rx Antenna Supervision by Comparing received signal strength indica-tor (RSSI) is to monitor the Rx antenna condition. Rx antennas can be monitored for major problems by taking a long-term average of the difference between the Main Rx RSSI and the Div Rx RSSI. This feature provides continuous antenna supervision for the BTSs, which have the Main Rx RSSI and the diversity in use. It also offers an alter-native solution for Tx monitoring in cells that use duplexing. This detects, for example, antennas with poor voltage standing wave ratio (VSWR) and inadequate feeders.

The monitoring is based on the principle that all received bursts where the Rx level of main or diversity branch is above the defined limit value (-100 dBm) are accepted as samples and used in the averaging process. A minimum of 160000 samples in one hour must be collected for the BTS to assume that the results are reliable and therefore could be used to raise an alarm.

The differences of the TRXs connected to the same antennas are counted up, and the average difference for main and diversity antennas is calculated. If the difference is above the threshold (default value 10 dB), and the number of samples indicate that the results should be reliable, an alarm is activated. The threshold default value of 10 dB can be changed by a parameter at the BSC between 3 and 64. The functionality of the feature can be disabled.

It is still possible that both antennas are damaged simultaneously and the samples from both antennas remain below -100 dBm limit value. Therefore, the difference algorithm cannot detect the fault. For this reason, the BSC also observes the assignment and handover success rate.

Note that the RSSI values observed from 2G Flexi BTS Site Manager may not be the same on both of the carriers of a RF Module. The difference between carriers can be greater than 10 dB, depending on the Rx level of the calls made on both carriers. If the average uplink Rx level of calls (CS/PS) made on Carrier 1 is high compared to Carrier 2, this difference can be seen and this is not a problem. It implies that calls on Carrier 1 are being made from mobiles that are near to the BTS, while calls on Carrier 2 are being made from mobiles that are relatively far from the BTS. The RSSI difference between two carriers is different from the case where an RSSI alarm is raised. The alarm is raised because of the difference in the Rx level of the main and diversity paths of a carrier. However, this alarm is not valid for the comparison done across carriers. Moreover, the comparison of RSSI values across carriers is not valid in UltraSite EDGE BTS, as a TRX in the UltraSite EDGE BTS supports one carrier only, whereas in the Flexi Multiradio BTS, the RF Module supports two carriers.

BenefitsRx Antenna Supervision by Comparing RSSI can identify antenna problems without the need for active tests.

Collection and display of raw RSSI measurementsIn addition to the newest and last reliable received signal strength indicator (RSSI) values, the BTS also gathers the raw RSSI results periodically from the TRXs. These results are displayed in the 2G Flexi BTS Site Manager.

Settable RSSI sample limitThe number of received signal strength indicator (RSSI) samples, needed for a valid RSSI calculation, can be configured using the Element Manager according to the traffic

38DN0967559 Issue 01A


Id:0900d8058076d047

density. The RSSI sample can be configured to values: 80000, 160000 (default), 350000 and 750000. The value 80000 is preferred when the BTS is located in a rural area and when the traffic density is low. The values 350000 or 750000 are preferred when the BTS is located in an urban area and has high capacity utilization. In areas with intermediate traffic density it is preferred to use the default value 160000.

The RSSI sample value may also be configured during the commissioning phase.

Alarm Start and CancelThe BTS estimates the number of samples it would receive for high/medium traffic profiles by setting an internal threshold value, which is a multiple of the user defined RSSI sample count. This value is an internal value and is not visible to the user.

The RSSI alarm is raised when:

– In the first hour, the received sample count is greater than the internal threshold and the RSSI alarm conditions are valid.

– In the first hour the received sample count is greater than the user configured RSSI sample threshold, but less than the internal RSSI alarm threshold. Then, the BTS software waits for the next hour to determine whether the RSSI alarm is to be raised.

– In the consecutive second hour the received sample count is greater than the internal RSSI alarm threshold or the user configured RSSI sample threshold and the RSSI alarm conditions are valid. If the user configurable sample count is changed during this hour then the monitoring is reset and the process restarts from the first hour.

The alarm is cancelled automatically in the next hour if the sample count is greater than the user configured sample count and the alarm condition has been cleared.

DN0967559 Issue 01A39


Id:0900d8058076d04a

5.13 BSS9068 BTS SW managementThe BTS software package consists of a master file and several application files. You can update the BTS software by downloading the new BTS software remotely from the BSC. A site visit is not needed.

You can download the BTS software to a BCF in the background during normal opera-tion, without impact to ongoing traffic or any other operation of the base station. Software downloading is also automatically triggered after BCF reset if the System Module does not have the correct BTS software package stored locally (that is, the package set as default for that particular BCF at the BSC).

When the BTS software is downloaded from the BSC, the process is optimized by down-loading only those application files which have been updated. Application files that are unchanged from those already stored locally in the current BTS software package are not downloaded. This minimizes the download time for a new BTS software package.

You can also download the BTS software with 2G Flexi BTS Site Manager to minimize BTS boot-up time for new installations. In this case you do not need to download the BTS software package from the BSC after BCF reset.

The downloaded BTS software package is stored in the flash memory of the System Module (ESMB/C). The flash memory of the System Module contains two complete BTS software packages to ensure recovery in the event of a download or start-up failure.

40DN0967559 Issue 01A


Id:0900d8058076d050

5.14 BSS9058 BTS fault recoveryBTS fault recovery minimizes the effect of service level faults within the BTS. All objects and interfaces are continuously monitored, and appropriate recovery actions are taken when needed. Alarms are raised to indicate faults, which leads to recovery actions being taken.

For more information on fault recovery and BTS alarms, see Trouble Management of Flexi Multiradio BTS GSM/EDGE.

DN0967559 Issue 01A41


Id:0900d8058076d053

5.15 BSS9063 Abis loop testThe purpose of the Abis loop test is to verify the Abis transmission set-up and quality. During the Abis loop test, Flexi Multiradio BTS generates a test signal pattern in Abis uplink for the timeslots under test. The BSC group switch loops the selected timeslots back to Abis downlink where the BTS checks the integrity of the received signal. The Abis loop test can be run on the TCH and Dynamic Abis Pool timeslots. After the test, the BTS provides the related test reports to the BSC. The Abis loop test is run automat-ically during BTS commissioning. The test can also be run manually from the BSC.

Up to 12 simultaneous Abis loop tests can be tested if no Abis protection loops are used. If they are used, then up to 6 Abis loop tests can be run simultaneously.

42DN0967559 Issue 01A


Id:0900d8058076d056

5.16 BSS9062 BTS supervisionThe Flexi Multiradio BTS Base Station monitors and tests itself during operation without a separate command.

Continuous monitoringBoth the software and hardware carry out monitoring. Most of the monitoring procedures are so effective that no additional testing to find the faulty module is needed. The follow-ing items are monitored continuously:

• Internal buses of the base station • Transmission equipment and interfaces • RF parts • Mast head amplifiers • Flexi Support and Flexi Multiradio BTS Base Station Battery Backup (MIBBU) • Temperature (heating and cooling) system of the base station • Power supply voltages • Reference Oven Oscillator

AC mains breakdownA typical short voltage drop (that lasts less than 20 ms) in the AC mains supply does not cause any detectable harm to the operation and does not cause an alarm. In case of a mains breakdown, the Flexi Multiradio BTS Base Station cannot send an alarm to the BSC without battery backup (either integrated or external).

DN0967559 Issue 01A43


Id:0900d8058076d059

5.17 BSS9061 Temperature control systemFlexi Multiradio BTS Base Station monitors its temperature continuously with several sensors located in the System Module (ESMB/C) and RF Module (FXxx).

The BTS controls its temperature with cooling fans to provide as stable operational con-ditions as possible. Heating and cooling is controlled gradually depending on the ambient temperature to ensure low temperature gradients and noise level.

During commissioning, a climate control profile can be selected from three options depending on the BTS site environment:

• LOW NOISE minimizes fan noise for low and moderate ambient temperatures. • OPTIMISED COOLING (default profile) maximizes unit reliability by running fans

with maximum speed already in moderate ambient temperatures. • LINEAR RESPONSE is an intermediate profile which increases fan speed linearly

as the temperature increases.

If the temperature of a module rises too high, a temperature alarm is issued. If the System Module is overheated, the BCF is blocked. If the RF Module is overheated, the associated TRXs are blocked. Power supply units have their own internal shutdown and recovery in case they are overheated.

All Flexi Multiradio BTS modules operate over full operational temperature range without the need for external heaters.

44DN0967559 Issue 01A


Id:0900d8058076d05c

5.18 BSS9060 TRX TestThe total performance of the TRX is tested with a multi-purpose TRX Test. The test covers:

• Digital and RF parts • Rx operation and Tx level • Both Rx branches

The TRX test time is approximately 15 seconds.

When the TRX test is carried out according to a regular schedule, it can be used in TRX performance supervision.

Both Rx branches are tested separately during the same TRX test. If diversity is not con-figured, only the main branch is tested.

The TRX Test tests both the Tx and Rx RF paths of the selected TRX via an up looped burst to the Air interface, including the RF Module (FXxx). The looped back signal is fed back to the Rx path where the BER, Rx Level, and Rx Result are measured. The reported Tx power is derived from the received RX level.

The Tx power level used during the TRX test is the same as the power level of the broad-cast control channel (BCCH). To avoid unwanted disturbances to the TRXs, the training sequence is not the same as the one normally used.

Figure 7 TRX Test window

All TRXs in the BTS can be tested either remotely from the BSC or the NetAct or locally/remotely with 2G Flexi BTS Site Manager. If the TRX test which is run from NetAct or the BSC fails, the test must be rerun remotely or locally with 2G Flexi BTS Site Manager. The 2G Flexi BTS Site Manager then informs the detailed failure reason, which can be used for troubleshooting with the instructions that can be found in the doc-ument, Trouble Management of Flexi Multiradio BTS GSM/EDGE.

DN0967559 Issue 01A45


Id:0900d8058076d05c

It is possible to run the TRX Test after the TRX object is blocked from the 2G Flexi BTS Site Manager. It is also possible to run the TRX Test after the TRX object is locked from the BSC.

Note that the TRX test can be performed only in traffic channel (TCH) timeslots. Two free timeslots are needed for the test.

The TRX test is not possible when baseband or antenna hopping is used.

Also TRX Test cannot be commanded for a TRX configured to cover the extended/super extended outer area.

46DN0967559 Issue 01A


Id:0900d8058076d05f

5.19 TRX Loop TestFlexi Multiradio BTS provides a TRX Loop Test facility. In a TRX loop test, data gener-ated by SW in digital parts of the TRX is looped from the TX to RX side inside the RF Module (FXxx), so that the TX and RX chains excluding antennas and antenna feeder cables are tested. Main or diversity paths can be tested.

The BTS checks the looped test data, and the test result is given as BER values.

The TRX Loop Test can be performed with GMSK TCH/FS or 8PSK PDTCH/MCS-5 test channels.

DN0967559 Issue 01A47


Id:0900d8058076d062

5.20 BSS9059 BTS resetsYou can separately trigger a reset of BCF, BTS or TRX objects. An object reset can be triggered from the BSC, NetAct and from 2G Flexi BTS Site Manager. In addition, the 2G Flexi BTS Site Manager can also command HW resets for the System Module (ESMB/C) and RF Module (FXxx).

Object resets

• BCF (site) reset: resets all modules/units in the site except transmission sub-modules (FIxA), which ensures that active cross-connections are not interrupted.

• BTS (sector) reset: resets a single BTS object, including all TRXs that are part of the BTS object configuration. It has no impact on other BTS objects which are part of the site.

• TRX reset: resets a single TRX. Only the targeted TRX object is impacted.

Module resetsModule resets are provided as a recovery mechanism for exceptional conditions. In normal operation, there should be no need to invoke this type of reset.

• System Module reset: reinitializes all hardware and software in the System Module. This is equivalent to a power on reset. Transmission is also re-initialized, and there will be a brief interruption in the cross-connect traffic.

You can also issue a specific sector or BCF object reset from 2G Flexi BTS Site Manager to force the RF Cable Auto-detection to the reset sector object, or to the whole BTS (all sectors). For more information on RF Cable Auto-detection, see section Auto-detection of Site Configuration and RF Cable Auto-detection.

48DN0967559 Issue 01A


Id:0900d8058076d065

5.21 BTS Auto-detection

5.21.1 BSS9056 Auto-detection of Site ConfigurationFlexi Multiradio BTS Base Station detects the site configuration automatically, including all active modules, their hardware versions, and product codes. This information is stored in the non volatile memory of the System Module (ESMB/C), and it can be dis-played in 2G Flexi BTS Site Manager.

The user needs to set the operator-specific settings, such as external alarm line settings, from the BSC or the NetAct, for example with the SCF.

The following Baseband Bus properties are detected:

• State - disconnected/established • Technologies that the hardware is shared with • Whether the configuration carries only payload, or FCB and Ethernet also • Distance between the System Module and RF Module

In addition to the attributes mentioned above, the timing, routing, capacity allocation rules, and register views can also be viewed.

A possible change in any of the modules or in the configuration causes an automatic site configuration update in the flash memory of the System Module. The configuration is detected both in normal start-up situations and when extra capacity (more TRXs) is added, modules are removed, or a faulty module is replaced with a new one. The trans-mission configuration is part of the site configuration file (SCF), which is stored in the System Module (ESMB/C).

There is no auto-detection for the mast head amplifier and power modules.

DN0967559 Issue 01A49


Id:0900d8058076d06b

5.22 48 V DC input voltage supervisionBoth the System Module (ESMB/C) supervise the 48 V DC input voltage continuously. When the input voltage decreases below 44.0 V DC or increases above 58.0 V DC, BCF notification alarm 7602 Supply voltage to ESMB/C near low/high limit is activated to indicate that the input voltage is close to exceeding its normal operating range.

For configurations where both the ESMB/C Module, if the input voltage continues to decrease below 39.0 V DC or increase above 60.0 V DC, all the RF Modules (FXxx) con-nected to the ESMB/C Module is shut down to protect their hardware. Alarm 7606 PDU Control has switched off EXxx TRX Module is activated to indicate that the BTS has shutdown the RF Module due to out of range input voltage.

When the input voltage increases up to and above 39.0V DC or falls down to and below 58.0 V DC, the RF Modules (FXxx) are powered up and the 7606 alarm is cancelled. Once the input voltage increases above 45.0 V DC or decreases below 57.0 V DC the 7602 notification alarm is cancelled.

50DN0967559 Issue 01A


Id:0900d8058076d074

5.23 BSS20958 Energy saving mode for BCCH TRXThe feature introduces a configurable power saving mode for the BCCH TRX. It aims to achieve lower electricity consumption by reducing the average transmit power of the BCCH TRX.

DN0967559 Issue 01A51

Flexi Multiradio BTS GSM/EDGE Feature Descriptions Site solutions

Id:0900d8058076d09f

6 Site solutions

6.1 BSS10046 Multi BCF ControlThe cell capacity can be increased with the Multi Base Control Function (BCF). Multi BCF is an application software product that allows combining resources of several physical base stations into one logical cell. Flexi Multiradio BTS cell capacity can be increased up to 108 TRXs with Multi BCF/common BCCH. For more details, see GSM/EDGE BSS, BSC and TCSM Product documentation. Multi BCF also provides a path for site expansion from UltraSite EDGE BTS to Flexi Multiradio BTS GSM/EDGE.

Multi BCF Control requires that BSS9055 Clock Synchronisation between base stations, or BSS10069 Synchronized BSS is used.

The operator can arrange base stations so that the TRXs in different base stations (operating on the same frequency band) can serve the same cell with a single BCCH. At the base station site, the operator needs to make some installations, for example syn-chronisation is needed between the base stations. All the base stations will have a separate O&M link to the BSC. At the BSC, a SEGMENT (SEG) object must be used to set all the BTS objects sharing the same BCCH.

Figure 8 Multi BCF configuration

Multi BCF cell (= SEG)

f1 f2 f3

f4 f5

UltraSite TRX group

Flexi TRX group

52DN0967559 Issue 01A


Id:0900d8058076d085

6.2 BSS9055 Clock Synchronisation between Base StationsClock Synchronisation between Base Stations enables synchronous handovers between base stations. The sectors defined to different base stations can use common hopping frequencies with RF hopping, which increases the channel capacity. The maximum site configuration is nine Flexi Multiradio BTSs in a chain.

The Flexi Multiradio Base Station has an external clock interface that can be used to synchronize the air interface between several Flexi Multiradio Base Stations located on one site.

When several Flexi Multiradio Base Stations are synchronized, the master base station (master BTS) functions as the frame clock source to the slave BTSs. The master BTS transmits the frame clock and frame number signals to the external clock line, while the other BTSs (slave BTSs) receive these signals. The slave BTS uses the received frame clock signal as a reference clock signal to adjust its main frequency source. The master BTS uses the reference clock signal derived from the Pulse Code Modulation (PCM) signal.

It is possible to synchronize a Flexi Multiradio Base Station to a UltraSite EDGE BTS to serve the adjacent sectors. In this case the clock master is always a UltraSite EDGE BTS.

In Pseudowire Emulation (PWE) mode, the following synchronisation sources are offered:

• Adaptive clock recovery based on a PW • Synchronisation via E1 • Synchronisation via 2 MHz input (ITU-T G.703) • Synchronisation to a system reference clock (that is, a clock used by the BTS like a

GPS) • 1 Pulse Per Second (PPS) signal as external sync source

The performance of the adaptive clock recovery is very much dependent on the perfor-mance of the packet-switched network. It is recommended to trial use the adaptive clock recovery for gaining information about if the network performance is sufficient for this option.

Physical propertiesThe maximum cable length for the total system is 100 meters. The synchronisation chain between the BTSs is made using RS-485 connection for the transferred clock signals.

Synchronisation recoveryIf there is a failure in the synchronisation between the base stations, the slave BTS gen-erates an alarm and the BSC then blocks all TRXs of the alarming BCF. When the fault disappears, cancellation to the alarm is sent to the BSC. The BSC then unblocks the TRXs under the alarming BCF object.

Fast tuning

• If the clock reference is taken from Abis:If the BTS is being commissioned, the fast oven-controlled crystal oscillator (OCXO) tuning is executed for the maximum duration of 8.6 seconds. The target accuracy is 0.02 ppm. The adjustments can be 10 times larger than in normal tuning. After fast tuning, the BTS starts normal tuning, and allows the BTS configuration to be com-pleted.

DN0967559 Issue 01A53


Id:0900d8058076d085

• If the clock reference is taken from an external synchronisation source (other BTS or LMU):If the BTS is being commissioned, the fast OCXO tuning is executed for an indefinite duration until the target accuracy of 0.02 ppm is met. Typically, the external clock reference is stable, therefore the fast tuning is completed in 36.92 seconds (eight rounds). The adjustments can be much larger than in normal tuning. After fast tuning, the BTS starts normal tuning, and allows the BTS configuration to be com-pleted.When an already commissioned BTS is started, the BTS starts performing fast tuning and starts configuration on TRXs. Since fast tuning configuration on TRXs are running in parallel, there is a possibility of handover failures for approximately one minute. However, this failure is seen only when the slave BTS is started with cali-brated DAC word which is far from the stable value. No handover failure is seen when the slave BTS is started with stable calibrated DAC word.

• With PWE and the adaptive clock recovery as the Abis synchronisation source, the performance of the lock-in to adaptive clock recovery will take approximately 10 minutes, but depending on the condition of the packet-switched network, can take considerably more time. The BTS will wait at commissioning until the lock-in is achieved before continuing with fast tuning.If the commissioning is aborted due to exceeding lock-in time allowance, the BTS will continue to achieve the lock-in and proceed to supervisory mode.

Normal tuningWith Abis as reference, the digital-to-analogue converter (DAC) word adjustment may occur every 20 minutes. The purity of Abis is monitored continuously, and the adjust-ment is only performed if the purity is good enough.

With an external clock as reference, the DAC word adjustment may occur every 20 minutes. The presence of the external clock source is monitored, the purity is not. When the external clock is present, the adjustment is made.

With both clock sources, the current DAC word is written as a new calibrated DAC word, if the current DAC word eventually drifts far enough from the calibrated DAC word. This ensures that in later start-ups (in any environmental conditions), the BTS starts immedi-ately with a value as accurate as possible, and the C-plane and U-plane signaling and traffic remain undisturbed.

With PWE and the adaptive clock recovery, it is possible to use the 4th E1 interface for relaying synchronisation to, for example, a co-sited BTS. This output is compliant to wander network interface requirements (ITU-T G.823). By not adhering to the synchro-nisation interface requirements, the output should only be used for a BTS synchronisa-tion application.

If the adaptive clock recovery synchronisation source is lost due to a degraded packet-switched network, the BTS will use a high stable OCXO for hold over. For approximately 13 minutes, the BTS is still showing the adaptive clock recovery as the synchronisation source and does not raise an alarm, filtering those short term intermediate disturbances.

54DN0967559 Issue 01A


Id:0900d80580792933

6.3 1 Pulse Per Second (PPS)A 1 Pulse Per Second (PPS) signal, generated from any source like a GPS receiver, can be fed to the SYNC IN connector of the System Module. This signal can then be used as a clock source for tuning the System Module OCXO. Since no frame number is encoded in the signal, just the BTS frequency/phase can be synchronized to this clock source. The required frame number and frame clock are generated BTS internally.

DN0967559 Issue 01A55


Id:0900d8058076d088

6.4 BSS10069 Synchronized BSSWith Synchronized BSS, all the clocks of the different sites in the network are synchro-nized, so that the GSM frame timing is aligned between all sites.

This is done by using a Location Measurement Unit (LMU), which gets a GPS time ref-erence, and uses this to generate clock signals for the BTSs.

Synchronizing all BTS sites in the network minimizes timing differences between TDMA bursts of different sites. The benefits are:

• Improved quality (higher data throughput, lower frame error rate (FER)) • Possibility of tighter frequency reuse • More effective cell re-selection and handover processes • More accurate MS locationing functionality

6.4.1 BSS20371 BSS Site Synchronisation Recovery ImprovementBSS Site Synchronisation Recovery Improvement is an enhancement to BSS11073 Recovery for BSS and Site Synchronisation. With BSS Synchronisation Recovery Improvement, the BTS site continues in the BSS Synchronized service even if the GPS coverage is lost for up to 24 hours. The BTS site also continues in the BSS Synchro-nized service throughout an LMU software update.

The transmission link(s) to the BTS site meet the Jitter and Wander requirements of ANSI T1.403 for T1 links, or ITU G.823 for E1 / 2048 kbit/sec hierarchy links.

Interaction with other featuresImproved BSS Synchronisation Recovery is used in any networks which use BSS Syn-chronisation.

6.4.2 BSS11073 Recovery for BSS and Site SynchronisationThe main purpose of Recovery for BSS and Site Synchronisation is to give automatic recovery for BSS Synchronized sites (sites with LMU) if the BSS 20371 Site Synchroni-sation recovery improvement is not used.

• when the Location Measurement Unit (LMU) clock signal is lost, to get the chained BTS cabinet (site) into unsynchronized mode

• when the LMU clock signal is again available, to return the chained cabinet back into Synchronized mode

Recovery for BSS and Site Synchronisation also offers synchronisation recovery for a Multi BCF site using BSS9055 Clock Synchronisation.

When the BTS chain is defined in the BSS radio network database, Recovery for BSS and Site Synchronisation automates the recovery if the BTSs in the chain are Synchro-nized and the clock signal is lost and regained. On the other hand, if the chain is not defined or the BSS or Site synchronisation of the chain has not been activated, the sites need to be locked and unlocked in the correct order to enable system synchronisation. The BSC receives the information for recovery from Q1 and BTS alarms.

For a Flexi Multiradio BTS chain, the maximum number of BTSs is nine.

56DN0967559 Issue 01A


Id:0900d8058076d088

Figure 9 Synchronized BSS example in Flexi Multiradio BTS chain

The BSS is Synchronized by a Global Positioning System (GPS), that is, LMUs are installed to every site with GPS antennas. The clock source is a GPS satellite via the LMU. When the LMU feeds the clock, all BTSs are working as slaves. When the LMU clock feed is lost, the BSC starts a timer. The Synchronized operation continues unin-terrupted based on the BTS internal clock. If the BSC timer expires, the first BTS in the chain becomes a clock master and starts supplying the clock signal to the other BTSs. The BTS synchronisation status indication in the BSC is changed to 'unsynchronized'. When the LMU clock is recovered, the BTS becomes Synchronized again.

BenefitsAutomatic recovery for the loss of LMU clock, when the BTS chain is defined in the BSS radio network database:

• Automatic BSC-controlled recovery to unsynchronized operation • Automatic BSC-controlled return to Synchronized operation • Timeslot offset parameter sending to LMU • BTS synchronisation configuration and mode information available from the BSC by

MML and NetAct

BSC

LMU(master)

BTS(Flexi)(slave)

IN OUT

Abis

FN Offset

Q1

FN, FCLK

BTS2(Flexi)(slave)

IN OUT

BTS3(Flexi)(slave)

IN OUT

FN, FCLK FN, FCLK

DN0967559 Issue 01A57


Id:0900d8058076d08b

6.5 Operating bandsFlexi Multiradio supports the following operating bands:

• GSM 900 • GSM 1800

Dual and Tri Band Common BCCHCommon BCCH allows the combination of two or more sectors into a single logical cell, with a single BCCH carrier. With common BCCH sectors in different frequency bands such as 900/1800 MHz (or 800/1900 MHz, or 800/1800 MHz) can be configured with a common BCCH carrier.

The main advantages of the common BCCH functionality are:

• Improved trunking gain • Use of signaling channels is optimized by sharing them between bands • Tighter reuse of all carriers in the non-BCCH bands • Better call quality because of decreased number of handovers

To ensure proper operation of the network, take into account issues related to the differ-ence of propagation between the different bands when performing cell planning.

Figure 10 Common BCCH configuration

Frequency hopping between bands in the same sector is not supported.

Common BCCH cell

f1 f2 f3

f6 f7 f8

f4 f5

PGSM 900 TRX group

EGSM 900 TRX group

GSM 1800 TRX group

58DN0967559 Issue 01A


Id:0900d8058076d08e

6.6 BTS2043 BTS External Alarms and Controls (EAC)External Alarms and Controls (EAC) signals can be defined to the BTS.

BenefitsThe external alarms and controls allow alarms to be sent from external equipment attached to the BTS, and allow control of external equipment attached to the BTS.

External Alarms caused on the site, such as the intruder alarm, are sent to the NetAct via the Abis. The alarms are TTL level signals, all referred to 5 V. The operator can define whether an alarm is raised when the alarm input line is grounded or disconnected from the ground potential (this is known as alarm polarity). This allows more flexibility for the alarming device.

The External Controls allow the user to control external equipment remotely from the BSC. The External Controls are of open-collector type.

The EAC settings (such as name, alarm polarity, control state) are defined at the BSC. The EAC names can be viewed at the BSC.

RestrictionsThere are 24 user-definable external alarms and 6 user-definable external controls. The System Module (ESMB/C) provides 12 alarm inputs and 6 control outputs. Another 12 alarm inputs are available with the optional Flexi System External Alarm Module (FSEB).

DN0967559 Issue 01A59


Id:0900d8058076d091

6.7 BTS2020 RX antenna diversityThe BTS receive sensitivity especially in fading conditions can be improved with multi-path receive diversity. 2-way diversity requires at least two antennas for each sector, one for both main and diversity Rx-signals. 2-way diversity also requires a receiver for each antenna, that is, at least two receivers. The 3-branch RF Module is optimized for 2-way diversity. The module has a diversity RX path in addition to the main RX path in each radio pipe. So, 2-way diversity can be configured in the RF Module without any additional BTS HW.

Diversity is defined for every sector separately from the BSC.

60DN0967559 Issue 01A


Id:0900d8058076d094

6.8 BTS configurationsFlexi Multiradio BTS is a cost optimized solution for single mode GSM/EDGE, WCDMA, or LTE networks or mixed multimode networks, enabling smooth evolution between dif-ferent network technologies. Flexi Multiradio BTS can be used for high capacity as well as high coverage macro or micro cellular applications, feederless sites, and mast top installations. Flexi Multiradio BTS has a 3-branch RF Module optimized for traditional BTS sites with or without cabinet installations. The RF Module is capable of serving 3 sectors with multimode multicarrier radios of up to 60W output power/branch. The GSM/EDGE configuration supports up to 6 sectors with 36 carriers (one BCF object).

6.8.1 Antenna-optimized configurationsThe following table lists the antenna-optimized configurations supported with Flexi Mul-tiradio BTS:

Configurations # of FXxx # of ESMB/C

# of FPAA1)2)

1) Optional depending on the external power source. The number of power modules is based on maximum power consumption and does not account for redundancy.

2) One FPMA supports up to four FPAAs. FPBAs may also be installed in the FPMA. See Installing Flexi Multiradio BTS GSM/EDGE Optional Items for more details.

# of FPDA1)

Total number of antennas

One RF Module antenna-optimized 2 up to 12 OMNI 2UD

1 1 2 1 12

Two chained RF Modules antenna-optimized 2+2+2 up to 12+12+12 2UD

2 1 3 2 12

Three chained RF Modules antenna-optimized 3+3+3 up to 12+12+12 2UD

3 1 4 2 18

Table 4 Antenna-optimized configurations

DN0967559 Issue 01A61


Id:0900d8058076d097

6.9 Flexi Multiradio BTS GSM/EDGE Feederless Site conceptFlexi Multiradio BTS GSM/EDGE Feederless and Distributed Site refers to a solution where the System Module and RF Module are installed at a distance from each other. The RF Module can be installed in the same location as the System Module, or at a distance of up to 15 km. Modules can be installed on a pole, wall, or floor.

The benefits of the Feederless and Distributed Site solutions compared to a traditional BTS site are listed below:

• Overall site RF performance is better compared to antenna feeders installation (the gain can be 2 to 5 dB).

• The solutions open easier, new, and optimized installation possibilities especially in difficult places.

• There is no need for mast head amplifiers.

Flexi Multiradio BTS GSM/EDGE feederless site solutions utilize various power distribu-tion solutions. DC feed to the feederless or distributed site is provided either by a Nokia Siemens Networks power system or 3rd party products. The input for the Optical Con-verter Module is floating 48 V DC. There are the following basic power supply alterna-tives for the BTS site and its modules:

• Flexi Power Module (FPMA) or MIBBU concept with a site support module, batter-ies, and cabinet

• FPMA installed near the RF Module • 3rd party AC/DC system (must meet the ETSI 300 132-2 standard)

6.9.1 Feederless siteIn a feederless BTS site, RF module can be installed at a distance from the System Module. This reduces the site investment and increases the RF performance as the antenna feeder lines are shorter or not needed at all when the site location is easy to access. BTS antenna line feeders are replaced with optical fiber connections. Flexi Mul-tiradio BTS has compatible optical OBSAI interfaces in the System Modules and separate optical converters are not required.

When DC is fed from the DC power system to the RF Module, the maximum distance is 100 m (measured from the power system equipment to the RF Module input). The BTS site can be either DC or AC powered (this concerns all the modules that require 48 V DC). In the latter case, an AC/DC converter (either the FPMA or a 3rd party converter) is required and the maximum length of the optical cable to be used is 200 m.

For information on installation distances see the Creating Flexi Multiradio BTS GSM/EDGE feederless site configurations document.

62DN0967559 Issue 01A


Id:0900d8058076d097

Figure 11 Feederless rooftop site

Flexi Multiradio feederless site supports:

• 1UD with RF Module configurations • 15, 30, 60W Tx power level with RF Module • A maximum of 3 RF Modules for a remote island • 1 shared RF Module and with a maximum distance of 200 m • EDGE license optimization • Dual band with any TRXs belonging to any band, but only 2 bands together • A maximum of 6 sectors • Where the distance is less than or equal to 20 Km and a maximum of 3 RF Modules

DN0967559 Issue 01A63

Flexi Multiradio BTS GSM/EDGE Feature Descriptions Basic GSM operation

Id:0900d8058076d0e5

7 Basic GSM operation

7.1 BSS21113 Increased dynamic SDCCH capacityThis feature is related to BSS7036 Dynamic SDCCH Allocation feature. When BSS21113 feature has been turned on at the BSC, the maximum number of SDCCH channels for each TRX is increased from 16 to 24 or 32, depending on the type of the TRX. It is increased to a maximum of 24 channels in BCCH TRXs and to a maximum of 32 channels in non-BCCH TRXs.

64DN0967559 Issue 01A


Id:0900d8058076d0a7

7.2 BSS20872 Robust AMR signalingRobust AMR signaling is an application SW product and requires a valid licence in the BSC. The SW product consists of four separate features:

1. FACCH and SACCH repetition for “repeated ACCH” capable mobiles on AMR TCH 2. FACCH repetition for legacy mobiles on AMR FR 3. FACCH repetition for legacy mobiles on AMR HR 4. FACCH Power Increment on AMR TCH

FACCH/SACCH repetition and FACCH Power Increment proposals are specified together as a single repeat/power increment function so that the BTS can optimize the use of the power increment and repetition according to the BTS Tx power level, mobile capability and channel (AMR FR, AMR HR) used.

The BSC's role is to provide parameters related to this feature to the BTS. The BSC checks the mobile’s capability and sends parameters related to this feature to the BTS at the beginning of a call (Channel Activation message). The BTS then uses the com-manded features according to the radio conditions. The BTS indicates the usage of FACCH/SACCH repetition and soft combining of repeated blocks in the Measurement Result message to the BSC. This information is used for monitoring of Robust AMR sig-naling.

With FACCH repetition, the time taken to get a command to a mobile increases, so rep-etition should only be applied when needed. Uplink SACCH repetition reduces the fre-quency of measurements from the mobile, so it should also be used only when needed. Repetition of the same measurement reports also affects the averaging of measure-ments and the reaction speed of handover and power control algorithm.

Repeated AMR SACCH and FACCH in 3GPP Release 6With 3GPP Release 6 and onwards, mobiles and BTSs can ask for SACCH frames to be repeated exactly on transmit so that the original frame and its repeat can be decoded together using Incremental Redundancy (soft combining) type decoding, similar to the IR defined for EDGE data. Similarly, transmit repeat and Incremental Redundancy on decode can also be used with downlink FACCH frames.

This gives about a 4 dB improvement in the C/I needed to decode the SACCH and FACCH so that these channels are as robust as the lowest rate AMR codecs.

BSS13 supports the 3GPP protocol for repeated SACCH and FACCH, and will use the Incremental Redundancy on the uplink SACCH when needed for good normal operation of the control channels.

Repeated AMR FACCH for existing mobilesFor mobiles designed according to ‘old’ 3GPP releases (that is, releases up to and including Release 5), 3GPP has enhanced the radio interface protocol so that the downlink FACCH can be repeated, to give the mobile two chances to decode the FACCH before each link timeout and retry of the protocol. This gives about a 2 dB improvement in the C/I needed to decode the FACCH, so that this channel is more robust and the dropped call rate in handovers is reduced.

BSS13 will use the repeated downlink FACCH when the mobile is indicating poor downlink quality by requesting a low-rate AMR CODEC.

DN0967559 Issue 01A65


Id:0900d8058076d0a7

The 2 dB improvement in the C/I is not enough for reliable operation with the very lowest rate AMR/FR codecs, so Nokia Siemens Networks also offers the FACCH Power Incre-ment feature for the existing mobiles.

FACCH Power Increment for existing mobilesWith this feature, for 3GPP Release 5 and earlier mobiles, the BTS Tx power for (down-link) AMR FACCH bursts can be increased by 2 dB, up to the maximum power capability of the TRX. The Power Increment is not used when transmitting on the BCCH frequency.

This will give an improved C/I for FACCH so that the dropped call rate in handovers is reduced, but without adding significant interference to other ongoing calls. Combining this feature and the Repeated AMR FACCH for the existing mobiles, BSS13 offers up to 4 dB improvement in the C/I for FACCH decode, and a corresponding reduction in the handover dropped call rate.

66DN0967559 Issue 01A


Id:0900d8058076d0aa

7.3 BSS20588 TRAU bicasting in AMR FR/HR handoverAMR speech codec is a key voice codec in Nokia Siemens Networks GSM/EDGE BSS. AMR packing/unpacking is one of the most important system level capacity/quality tools of the Nokia Siemens Networks AMR system feature. AMR packing/unpacking uses intra-cell handovers in order to change speech coding between AMR HR and AMR FR.

In order to reduce audio breaks during a handover, the BSC establishes a unidirectional connection in the downlink towards the target channel (bicasting) before the handover. For an AMR FR/FR (or AMR HR/HR) handover, bicasting means that TRAU frames carrying 16k (or 8k) TRAU coming from the transcoder (TC) are transmitted by the BSC simultaneously to the source and target channels in 16k (or 8k) format depending on the channel rate.

This method, presented in the following figure, tries to ensure that valid speech frames are being transmitted in the downlink over the air interface before the MS moves from the source to the target channel.

Figure 12 TRAU bicasting in AMR FR/HR handover

With this approach, it is possible to reduce the potential for breaks in audio in the downlink during a handover. TRAU bicasting in AMR FR/HR handover also enables to establish a unidirectional connection in AMR FR/HR intra-BSC handovers. When this feature is used, source and target BTSs and TC are all using 8 kbit/s TRAU frame format for Abis and Ater transmissions during an AMR packing/unpacking handover. In prac-tice, this means that the 8 kbit/s TRAU frames are sub-multiplexed onto a 16 kbit/s Abis channel of the BTS that is sending/receiving TCH/AFS radio frames.

TC

BSC

TC

BSC

TC

BSC

DL

DN0967559 Issue 01A67


Id:0900d8058076d0ad

7.4 Basic GSM featuresFlexi Multiradio BTS supports the following basic GSM channel combinations:

• Combined broadcast control channel (BCCH) including • frequency correction channel (FCCH) • synchronisation channel (SCH) • common control channel (CCCH) • standalone dedicated control channel (SDCCH/4) • slow associated control channel (SACCH/C) • random access channel (RACH)

• Non-combined broadcast control channel (BCCH) including • frequency correction channel (FCCH) • synchronisation channel (SCH) • common control channel (CCCH) • random access channel (RACH)

• Standalone dedicated control channel (SDCCH) including • Standalone dedicated control channel (SDCCH/8) • Slow associated control channel (SACCH/C)

• Full rate speech (TCH/FS, TCH/EFS, TCH/AFS) with • Slow associated control channel (SACCH/T) • Fast associated control channel (FACCH)

• Half rate speech (TCH/HS, TCH/AHS) with • slow associated control channel (SACCH/T) • fast associated control channel (FACCH)

• Full rate circuit-switched data (TCH/F24, TCH/F48, TCH/F96, TCH/F144) with • slow associated control channel (SACCH/T) • fast associated control channel (FACCH)

68DN0967559 Issue 01A


Id:0900d8058076d0b0

7.5 BSS6071 Enhanced Full Rate CodecEnhanced Full Rate Codec (EFR) uses the existing GSM 900/1800 full rate channel coding but provides a considerably better performance in all channel conditions. More-over, in good channel conditions, the codec ensures equal or better quality than Adaptive Differential Pulse Code Modulation (ADPCM).

The EFR can coexist with Half Rate (HR) or Full Rate (FR) 'dual codec'.

DN0967559 Issue 01A69


Id:0900d8058076d0b3

7.6 BTS2023 Downlink and uplink DTXDiscontinuous transmission (DTX) is a mechanism allowing the radio transmitter to be switched off during speech pauses. This feature reduces the power consumption of the transmitter, which is important for mobile phones, and decreases the overall interfer-ence level on the radio channels affecting the capacity of the network.

The DTX function is supported both in downlink and uplink for the following speech channels: TCH/FS, TCH/EFS, TCH/AFS, TCH/HS, and TCH/AHS.

70DN0967559 Issue 01A


Id:0900d8058076d0b6

7.7 BTS2503 Compressed Abis timeslot allocationIn traditional transmission solutions, some capacity is left unused, especially in the case of BTSs with one TRX, because one radio interface time slot is always used for the broadcast control channel (BCCH). The compressed Abis time slot allocation makes it possible to use this capacity for TRX signaling. This slot can 'steal' the traffic channel (TCH) transmission slot, which leaves capacity for six full rate TCHs or twelve half rate TCHs for that TRX.

In environments where it is not necessary to use the full traffic capacity of a TRX, com-pressed Abis time slot allocation offers an ideal solution for using the transmission medium more efficiently. With this configuration, it is possible to fit 15 TRXs to one 2 Mbit/s PCM.

DN0967559 Issue 01A71


Id:0900d8058076d0ba

7.8 BTS2067 Fast Associated Control Channel (FACCH) Call SetupWith Fast Associated Control Channel (FACCH) Call Setup, it is possible to establish a call without using a stand-alone dedicated control channel (SDCCH). A traffic channel (TCH) is set to 'signaling only' and switched over to normal speech operation when needed. FACCH Call Setup is for emergency calls only.

72DN0967559 Issue 01A


Id:0900d8058076d0c0

7.9 BSS7036 Dynamic SDCCH AllocationDynamic Stand-alone Dedicated Control Channel (SDCCH) Allocation allows the SDCCH resources to be configured according to the actual SDCCH traffic situation of a cell. When the BTS temporarily needs greater SDCCH capacity than normal, the BSC configures the idle traffic channel (TCH) resources for SDCCH use. For an example of this, see the figure below. A maximum of two additional SDCCH/8 can be configured. When the SDCCH congestion situation is over, the extra SDCCH resources are config-ured back to TCH resources. Dynamic SDCCH Allocation can be used with both combined and non-combined Broadcast Control Channel (BCCH).

The BTS only needs to be configured to the minimum static SDCCH capacity sufficient to handle the normal SDCCH traffic.

Figure 13 Dynamic SDCCH allocation

An extra SDCCH resource is allocated only when the existing SDCCH is fully loaded. When the dynamic SDCCH radio resource is totally free again, it is immediately recon-figured for TCH use. Thus, the maximum number of TCHs is always in use depending on the actual need of the SDCCH resources at each moment.

Dynamic SDCCH Allocation benefits traffic cases in which signaling is the only transmis-sion to the network, for example Short Message Service (SMS) traffic and location updates. In some special places, such as airports and stations, the location updates can produce sudden short-term SDCCH congestion. With Dynamic SDCCH Allocation, this can be handled without any need to configure extra permanent SDCCH capacity.

TCH(busy)

TCH TCH(busy)

TCH(busy)

SDCCH/8

BCCH SDCCH/8 TCH(busy)

TCH(busy)

TCH(busy)

TCH(IDLE)

TCH(busy)

TCH

TRXwith staticSDCCH/8

New TRXconfiguration

with additionalSDCCH/8

SDCCH congestion triggersdynamic allocation of SDCCH for free FR RTSL

BCCH SDCCH/8 TCH(busy)

TCH(busy)

DN0967559 Issue 01A73


Id:0900d8058076d0c3

7.10 BTS2024 Synthesized frequency hoppingSynthesized frequency hopping is available for configurations that have at least two TRXs per sector. Synthesized frequency hopping enables all TRXs to change frequen-cies in successive timeslots, so that the carriers can hop at many different frequencies in quick succession. Both random and cyclic hopping can be used. The maximum number of frequencies per BTS site is 64. The number of frequencies can be greater than the number of TRXs.

Note that the BCCH carrier must remain at a fixed frequency and at a fixed power level to enable the MS to measure the signal strength.

74DN0967559 Issue 01A


Id:0900d8058076d0c6

7.11 BTS2013 Baseband Frequency HoppingIn Flexi Multiradio BTS, the RF Modules are interconnected through a Gigabit Ethernet L2 switch to facilitate baseband hopping. Both random and cyclic hopping can be used for baseband hopping. The number of frequencies used in the baseband hopping fre-quency hopping sequence is the same as the number of carriers in the sector. Baseband hopping is allowed for all BTS configurations except with over 150 m multimode fiber used with Feederless Site configuration.

DN0967559 Issue 01A75


Id:0900d8058076d0c9

7.12 BTS2037 Air interface measurement pre-processingThe measurement results for the active channels may be averaged for the TRX. This option is useful when 16 kbit/s signaling is used because it reduces the capacity needed on the Abis link. The averaging period may be set to consist of 1 - 4 SACCH multiframes. Both uplink and downlink measurements are averaged. As a result, the BSC receives a measurement report once at the end of the averaging period rather than after every SACCH multiframe.

76DN0967559 Issue 01A


Id:0900d8058076d0cc

7.13 BTS2012 BTS time base reference from PCMThe PCM clock is used as a reference when tuning the long-term accuracy of the BTS internal clock. The requirement for the accuracy is 0.015 ppm in order to meet the GSM requirement (0.05 ppm) for the clock signal accuracy in the Air interface.

DN0967559 Issue 01A77


Id:0900d8058076d0cf

7.14 BTS2133 Short Message Service (SMS) point-to-pointBase Station supports the short message service (point-to-point) for both mobile origi-nating and mobile terminating calls.

78DN0967559 Issue 01A


Id:0900d8058076d0d2

7.15 BTS2033 Short message cell broadcastThe short message service (cell broadcast) defined in the GSM recommendations is supported.

DN0967559 Issue 01A79


Id:0900d8058076d0d5

7.16 BSS6025 Short Message Service Cell Broadcast with Dis-continuous Receiving (SMS-CB DRX)SMS-CB DRX enables phase-2 Mobile Stations (MSS) to receive only the needed blocks of the CBCH (Cell Broadcast Channel). This decreases battery consumption.

The BSC has a user interface for SMS-CB (Short Message Services Cell Broadcast) and it stores CB messages in the BSS. After the BTS initialisation, the BTS operates in non-DRX (Discontinuous Receiving) mode until SMS-CB DRX is activated in the BSC. When SMS-CB DRX is employed, the BTS starts transmitting Schedule Messages to the cell area. A Schedule Message includes information about a number of immediately following consecutive CB messages, planned for that cell. The time between two Schedule Messages is called the Schedule Period. The Schedule Period is one minute (see the figure below).

The MS starts operating in DRX mode after the power up when it has received the first Schedule Message. If the MS does not receive a Schedule Message, it has to read at least the first block of each CB message.

Figure 14 SMS-CB DRX Schedule Period

In DRX mode, in the first block of the Schedule Message, the MS receives information about

• How many CB messages there are • In which slot they will be transmitted • Message identifiers (if there are fewer than 6 new messages)

If there are:

• No new CB messages in successive schedule periods, the MS ends up reading only the first block in each Schedule Message.

• 1 to 5 new CB messages, the MS does not need to read other blocks in the Schedule Message, but it still needs to read the new CB messages.

• More than 5 new CB messages, the MS has to read more than one block in the Schedule Message plus all the new CB messages.

SchCB1

CB2

CB31

Sch Sch

60 s

.... ....

CB1

80DN0967559 Issue 01A


Id:0900d8058076d0d8

7.17 BSS6083 Mobile Station (MS) speed detectionThe purpose of this feature is to determine the speed of the Mobile Stations (MSS) in GSM networks so that the fast moving MSS can be directed to macro cells and the slower moving MSS respectively to micro cells whenever configured so by the BSC. Fur-thermore, BSC statistics also collects this information.

The benefit of this feature is that it decreases the number of handovers in a micro-cell network and thus increases network capacity.

The BTS estimates the MS's speed by using the Crossing-rate algorithm. The algorithm is based on a comparison between the signal levels obtained from each burst and their averaged value over one SACCH multiframe. The algorithm counts the rate at which the signal level crosses the averaged signal level. The crossing rate is relative to the MS's speed. The BTS sends the measured MS-speed information to the BSC by including it in the 'Meas_res' message. The MS-speed indication can vary between 0 and 254 km/h (0 – 159 mph) in 2-km (1.25-mile) steps. If measurement averaging is used, MS-speed measurement results are also averaged (see the figure below).

Figure 15 MS speed detection used for handover decision

The handover-decision algorithm in the BSC takes into account the MS-speed results sent by the BTS. Furthermore, the MS-speed based handover parameters (nx, px, upper speed limit (USL) together with lower speed limit (LSL)) and the adjacent cell layer definitions are also used with this feature.

The handover (HO) and power control (PC) algorithm determines the need for the handover as follows:

• If px averaged MS-speed indications out of last nx averaged MS-speed indications exceed the USL, the MS is considered as a fast moving MS and the call will be handed over to a suitable upper-layer cell (macro cell) if any.

• If px averaged MS-speed indications out of last nx averaged MS-speed indications are lower than the LSL, the MS is considered as a slow moving MS and the call will be handed over to a suitable lower-layer cell (micro cell) if any.

Layer information and the umbrella handover criteria are used as the target cell selection criteria. This means that the RX level in the target cell has to exceed the umbrella handover requirement HO_UMBRELLA_LEVEL defined for every adjacent cell.

BSCBTS

BTS

Macro cell

Micro cell(s)

Fast MSs

Slow MSs

Meas_res

Crossing-rate algorithm

HOs

DN0967559 Issue 01A81


Id:0900d8058076d0d8

g The algorithm does not work with frequency hopping.

82DN0967559 Issue 01A


Id:0900d8058076d0e2

7.18 BSS20093 A5/3 cipheringThe ciphering algorithm A5/3 is a strong block cipher and provides improved security over air interface links when compared to A5/1 encryption. If the network capabilities are sufficient, A5/3 encryption should be deployed for maximum privacy over the air inter-face. Nevertheless, the A5/1 algorithm can be used as fallback solution.

DN0967559 Issue 01A83


Id:0900d80580790596

7.19 Multiple Operator BSS Configuration (MOBBS)The Multiple Operator BSS (MOBSS) feature allows sharing of Radio Access Network Elements, and their resources by different operators. From base station point of view this means sharing of the same RF resources respectively antenna(s) by 2G cells of dif-ferent operators.

Sharing is done according to the following:

• SCF allows defining more than one logical sector for the same set of RF resources respectively its related antennas

• 2G Flexi BTS Site Manager displays that an RF resource is shared by different logical sectors

• The maximum number of logical sectors per RF resource is 3 • The logical sectors may have different power levels. This has to be captured in the

SCF

g The frequencies of the multiple sectors used in a pipe should be non-overlapping. Consider a case of two sectors, one RF hopping and one non-hopping whereby the BCCH of the second sector is part of MA list of the first sector. Under such a condi-tion, there are cases where two Rx bursts are received on Air with the same fre-quency. In this case, the TRX test may fail. If we compare to Flexi EDGE, there is one key difference. AIR3 loop in Flexi EDGE is on carrier/sector basis. In Flexi Mul-tiradio, AIR3 loop is on pipe basis. So, if these sectors are in the same pipe in Flexi Multiradio, AIR3 loop, and subsequently, TRX test may fail.

EDGE license, MOBSS Optimized ConfigurationsThe following table lists the MOBBS optimized configurations supported with Flexi Mul-tiradio BTS:

Sectors imapped to same

antennas

Tx power Antenna optimized

# of FR pipes

# of SM (FSM/ES

Mx)

# of Antenna

Prefer-ence 1) (M/S)

1+1 30-30/40-20

No 1 1 1/2 S

2+2 15-15/20-10

No 1 1 1/2 M

3+1 15-15/10-30

No 1 1 1/2 S

1+1+1 20-20-20/30-15-15

No 1 1 1/2 M

2+1+1 10-20-20/15-15-15

No 1 1 1/2 S

2+2+2 10-10-10 No 1 1 2/4 S

Table 5 2 sectors using same pipes configurations

84DN0967559 Issue 01A


Id:0900d80580790596

1) Where M indicates mandatory and S indicates supported configurations.

It is possible to define more configurations with 2 or 3 pipes. MOBSS can support up to maximum 3 operators on one pipe.

EDGE license optimized, first digit expresses normal TRXs and second digit EDGE TRXs

3+1 EDGE opt

15-15 No 1 1 2/4 M

5+1 EDGE opt

10-10 No 1 1 3/6 M

7+1 EDGE opt

15-15 Yes 2 1/41 1/2 S

4+2 EDGE opt

10-10 No 1 1 1 S

6+2 EDGE opt

15-15/20-10

Yes 2 1 2 S

Sectors imapped to same

antennas

Tx power Antenna optimized

# of FR pipes

# of SM (FSM/ES

Mx)

# of Antenna

Prefer-ence 1) (M/S)

Table 5 2 sectors using same pipes configurations (Cont.)

DN0967559 Issue 01A85

Flexi Multiradio BTS GSM/EDGE Feature Descriptions Transmission

Id:0900d8058076d11f

8 Transmission

8.1 Basic transmission

8.1.1 Abis Trunk Transmission for E1 (ETSI) interfaceUp to four full rate (FR) or Enhanced Full Rate (EFR) speech channels, or up to eight Half Rate (HR) speech channels, are multiplexed on a single 64 kbit/s PCM timeslot. It is possible to create point-to-point star, multidrop chain or remote star transmission con-nections between BSC and BTS sites. This flexibility ensures that all kinds of transmis-sion needs are fulfilled: traditional star configuration, economical multidrop chains, and reliable multidrop loops are all possible.

Up to 12 TRXs are supported on a single 2 Mbit/s PCM line. See also BTS2503 Com-pressed Abis timeslot allocation.

Abis Trunk Transmission Allocation is implemented using the standard G.703 2 Mbit/s PCM frame structure.

For more information, see BSS Transmission Configuration in BSC/TCSM Product Doc-umentation.

Interaction with other featuresBSS30285 Activation of additional two E1/T1 interfaces

86DN0967559 Issue 01A


Id:0900d8058076d0ea

8.1.2 Abis Trunk Transmission Allocation for T1 (ANSI) InterfaceAbis trunk is a single transmission channel between two points, either the BSC or the BTS. Up to four full rate/enhanced full rate (FR/EFR), and eight with Half Rate (HR) speech channels are multiplexed on a single 64 kbit/s PCM timeslot. It is possible to create point-to-point star, multidrop chain or remote star transmission connections between BSC and BTS sites. This flexibility ensures that all kinds of transmission needs are fulfilled: traditional star configuration, economical multidrop chains, and reliable mul-tidrop loops are all possible.

Up to 10 TRXs are supported on a single 1.5 Mbit/s PCM line. See also BTS2503 Com-pressed Abis timeslot allocation. This feature is implemented using the standard T1.403 PCM frame structure.

The BTS supports Extended Super Frame (ESF) and SF/D4 framing. The ESF supports CRC-6 checks and 4 kbit/s data link for performance management.

Interaction with other featuresBSS30285 Activation of additional two E1/T1 interfaces

DN0967559 Issue 01A87


Id:0900d8058076d0ed

8.1.3 Abis Trunk SignalingRadio Signaling Link is a logical link between the BSC and the BTS in Layer 2. The RSL is identified by a functional address known as Service Access Point, SAPI=0. Radio sig-naling links over the Abis interface are addressed to different units by Terminal Endpoint Identifiers, TEI. The TEI values are fixed and correspond to the TRX-id. The TEI man-agement is not used.

One signaling channel is used for each transceiver (TRX) and one for each BTS base control function (BCF). Alternative signaling speeds are available: 16 kbit/s, 32 kbit/s, or 64 kbit/s. The selection of the signaling speed is done in the commissioning phase on BTS basis. The same selection is also done on the BSC site when channel configuration is defined.

Normally, 16 kbit/s TRX signaling speed is recommended for the FR operation. 32 kbit/s TRX signaling rate is recommended for the HR use.

88DN0967559 Issue 01A


Id:0900d8058076d0f0

8.1.4 Network SynchronisationIn normal network conditions, synchronisation information is carried by selected E1 or T1 paths from upper to lower hierarchical levels according to the synchronisation plan, from the MSC down to the BTSs.

Flexi Multiradio BTS selects the E1 or T1 signal that has the highest priority from a group of pre-selected digital paths as the active synchronisation signal. The operator can change the group of signals using the 2G Flexi BTS Site Manager application. Selection of a new signal is automatic in case of input failure and input recovery.

In addition to using E1 or T1 signals for synchronisation, it is possible to synchronize with an external clock signal, such as the LMU clock signal.

For Pseudowire Emulation (PWE) or Abis over IP mode, the following external synchro-nisation sources are available:

• One out of the 8 supported PWs • One out of four TDM 2 Mbit/s (E1) signals • An external 2 MHz signal or LMU • 1 PPS signal

g External 2 MHz and 1 PPS can also be use as sync source without PWE mode.

In the PWE mode, the synchronisation information can be forwarded via TDM IF 4 as E1 signal.

Network Synchronisation can be protected via PDH Loop Protection. See BSS30280 Abis loop protection for more details.

DN0967559 Issue 01A89


Id:0900d8058076d0f3

8.1.5 Transmission equipment managementThe management protocol for Nokia Siemens Networks transmission equipment is Q1. The transmission equipment can be external or internal to the BTS. The external equip-ment can be connected to the Flexi Multiradio Base Station using a Q1 cable or a con-figured Q1 embedded operations channel (EOC). In Pseudowire Emulation (PWE) mode, EOC configuration is not supported in the BTS.

Either the base station controller (BSC) or Flexi Multiradio Base Station can supervise the transmission equipment. The Q1 protocol is a master/slave protocol. The master regularly polls the slaves. If the BSC is the master, the transmission equipment is said to be under 'BSC polling'. If the Flexi Multiradio BTS is the master, the transmission equipment is said to be under 'BTS polling'. In PWE mode, the BTS does not support the BSC polling because the EOC configuration is not supported. Note that the BSC polling can still be configured for a BTS running in the PWE mode; the consequence is that transmission alarms are not reported to the BSC, the BSC may also show an alarm that any polling command sent via EOC configured in the BSC is not replied.

The alarms that the transmission equipment generates are transmitted to the BSC, which further transfers them to NetAct.

If the BTS is the master, the BTS reports the transmission alarms to the BSC via the OMUSIG channel.

If the BSC is the master, the BSC polls the alarms directly. A management channel must be configured throughout the transmission network between the BSC and the transmis-sion equipment. The management channel configuration at the BSC (service channel) must match the configuration at the transmission equipment (embedded operations channel). The BSC polling is only supported in the TDM mode.

All equipment on the same channel must have a unique address (polling address) to avoid conflicts. Only one master polls all transmission equipment. Loops are not allowed, because Q1 is a bus protocol.

With Flexi Multiradio BTS, it is not necessary to manually configure any Q1 switches to establish the internal Q1 paths. The configuration is done automatically based on the Q1 polling mode. As a consequence, all internal or external transmission devices connected to the BTS must be either BTS-polled or BSC-polled. A combination of polling modes is not possible. This is important to keep in mind particularly when configuring the external devices (which are connected to the BTS either via a Q1 cable or the EOC).

It is not possible to change the polling mode for the internal transmission equipment manually at the Flexi Multiradio BTS. It is the result of the configuration at the BSC. If the Q1 polling mode is 'BSC Polling', the Q1 address value is read from the BSC (0-3999). The Q1 address can be manually configured from the 2G Flexi BTS Site Manager. This should, however, be avoided to prevent conflicts.

With the Q1 Interface Handling BSC MML commands, the user creates the service channels used in communication between the BSC and the transmission equipment. The Q1 service channels are asynchronous serial communications channels. The default maximum number of Q1 service channels in the BSC is 18. The user must define every supervised equipment at the BSC. Altogether 512 pieces of equipment can be defined into Q1 service channels under the BSC.

90DN0967559 Issue 01A


Id:0900d8058076d0f6

8.1.6 Support for Microwave Radio LinksThe FlexBus transmission sub-module (FIFA) forms the integrated microwave unit support with Flexi Multiradio BTS.

One FIFA transmission sub-module is used per Flexi Multiradio BTS with two FlexBus interfaces, allowing for microwave radio tail and chain site topologies using FlexiHopper and MetroHopper.

The FIFA sub-module offers E1 bypass cross-connections from one FlexBus interface to the other, and up to 16xE1 add/drop capability to Flexi Multiradio BTS and sub 2M cross-connect function of which up to 8xE1 can be dropped to the BTS itself.

The FIFA sub-module is visible as a separate managed element at NetAct. The operator can manage the FIFA sub-module locally and remotely using FlexiHub manager. Flexi Multiradio BTS provides functions for alarm, performance data polling and forwarding to the BSC.

Some features related to Microwave Radio require an application SW licence, for example the L55341.05 licence for an additional FlexBus interface.

DN0967559 Issue 01A91


Id:0900d8058076d0f9

8.1.7 BSS9065 Transmission OperabilityFlexi transmission equipment is measured with several counters:

• All equipment can be measured within 15-minute/24-hour periods. This measure-ment gives a fixed set of counters, which are near-end G.826 signal quality counters. These counters are: • Total time • Available time • Errored seconds • Severely errored seconds • Background block errors • Errored block

• In the PWE mode, the following packet based counters are also available: • Received Ethernet Packets • Transmitted Ethernet Packets • Ethernet Received Errored Packets • Received PW packets in tunnel • Transmitted PW packets in tunnel • Packets not matching any PW* • Number of PW packets lost • Early Packets • Late Packets • Received PW packets with L bit set* • Delay Variation Average • Delay Variation Minimum • Delay Variation Maximum • Counters marked with a * are not reported to the BSC or NetAct

• A certain set of Flexi transmission equipment can be defined. Flexi transmission equipment refers either to the whole equipment or part of it (functional entity and supervision block). It is also possible to define the counters that are collected from the equipment. To do this, the topology of the transmission network must be known so that the measurement subject can be chosen.

92DN0967559 Issue 01A


Id:0900d8058076d0fd

8.1.8 BSS21234 Support for BTS PWE Counters at BSC/NetActPseudowire Emulation (PWE) provides the transparent transport of a TDM signal (E1) via a packet switched network (IP/Ethernet/UDP). The existing set of transmission alarms and counters was adapted to enable gathering performance data from BTS at NetAct. This facilitates network performance analysis for troubleshooting and optimiza-tion of packet switched network.

DN0967559 Issue 01A93


Id:0900d8058076d100

8.1.9 BSS21290 Flexi Multiradio BTS Ethernet SwitchingWith Ethernet Switching on the Flexi Multiradio BTS plug-ins FIQA and FIYA it is possible to use more the one Ethernet Interface; currently two FE’s and one GE are available. Thereby external IP/Eth equipment/networks can be connected, such as DCN (Data Communication Network).

Ethernet Monitoring for FIQA and FIYAIn 2G Flexi BTS Site Manager, Ethernet Monitoring functionality allows user to specify the monitoring configuration. The user can configure monitoring state, monitoring sources, and monitoring destinations. For more information see Commissioning Flexi Multiradio BTS GSM/EDGE document.

94DN0967559 Issue 01A


Id:0900d8058076d10e

8.2 Transmission solutions

8.2.1 PDH traffic routingCross-connections define how signals are routed from a transmission interface to another transmission interface. They are the basic building blocks for creating the path for transmitting the Abis capacity from the BSC to the BTS via interconnecting nodes.

Note that the cross-connections are only available in TDM mode.

Cross-connection granularitiesThere are several types of cross-connections available, and each has a different gran-ularity. Granularity means the bit rate at which a cross-connection is made, that is, the number of bits connected into a specific direction in a cross-connection. In 2 Mbit/s mode, the available granularities are:

• 8k (1 bit) • 16k (2 bits) • 32k (4 bits) • 64k (all 8 bits in a time slot) • n x 64k (where n = 1 - 31)

BSS21129 GroomingThe cross-connection feature of the transmission units makes traffic grooming possible.

Flexi Multiradio BTS is capable of grooming traffic at for example 8 kbit/s granularity, which enables fully optimized and flexible use of the available transmission resources. This ensures that the path used for transmitting Abis capacity can be used efficiently.

Note that the grooming is only available in TDM mode.

DN0967559 Issue 01A95


Id:0900d8058076d108

8.2.2 BSS30280 Abis loop protectionPDH loop protection is an efficient way to protect traffic in a transmission network such as a base station subsystem (BSS). In a live telecommunications network it is important to secure, in addition to the actual payload traffic, the network synchronisation and the centralized network management during any period of abnormal circumstances.

For these reasons, PDH loop protection protects:

• payload traffic • network synchronisation • network management connections

A transmission loop formed with elements consists of a loop master and one or more loop slaves. Usually the loop master is a transmission node, whereas the loop slaves can be either transmission nodes, BTSs or a combination of both inside one loop.

The loop principle is that the transmitted signal is always sent in both directions, but the received signal is selected from one direction only. The loop master sends pilot bits on the basis of which the switching decision is made. Each individually protected slave station needs one pilot bit.

Network synchronisation must also be ensured in a loop network, and it follows the loop principle in a similar way. The synchronisation switching takes place independently from the pilot bits by having master clock bit (MCB) and loop control bit (LCB).

Based on the configured priorities, each network element decides individually from which direction the signal and the synchronisation will be received, and, thus, it does not require any external or additional supervision for its decision.

Figure 16 Loop principle

Nokia Siemens Networks's way of implementing loop protection is ultimately secure, providing very fast route switching that recovers the transmission connections instantly. loop protection is embedded and thus very fast. The loop protection protects against fail-

Loopmaster

= Loop slave

Normal receive direction

Reverse receive direction

Pilot bitsPilot bits

Direction 1Direction 2

Transmissionnetwork

96DN0967559 Issue 01A


Id:0900d8058076d108

ures, such as cable-cuts, equipment failures, heavy rain and multipath fading, and against obstacles in the line-of-sight, such as cranes and growing trees.

Compared to an unprotected wireless network, PDH loop protection increases site avail-ability at least tenfold and prevents end-of-chain availability degradation.

The protection functionality is compatible with the existing BSS transmission.

Flexi Multiradio BTS can only act as a slave node in a PDH Loop protected network.

Note that the loop protection is only available in TDM mode.

For more information refer to the PDH Loop Protection in GSM Networks document that can be obtained upon request.

DN0967559 Issue 01A97


Id:0900d8058076d10b

8.2.3 Redundant Abis TrunkIf a failure or a problem in the transmission connection occurs between the BSC and the BTS sites, an alternative transmission route (redundancy) is desirable.

Two alternative strategies are available for redundancy:

• a duplicated point-to-point type connection • a redundant multi-drop loop connection

These two alternatives provide solutions for different transmission needs: either the tra-ditional redundant point-to-point configuration or the economical multidrop loop config-uration.

Redundant Abis Trunk for E1 interface (ETSI) is implemented by using the standard G.703 2 Mbit/s PCM frame structure.

Redundant Abis Trunk for T1 interface (ANSI) is implemented by using the standard T1.403 1.5 Mbit/s PCM frame structure.

Note that the Redundant Abis Trunk is only available in TDM mode.

For more information, see BSS Transmission Configuration in BSC/TCSM Product Doc-umentation.

98DN0967559 Issue 01A


Id:0900d8058076d113

8.3 BSS30305 Flexi Multiradio BTS Abis over IP/EthernetThe purpose of this feature is to start with the traditional Abis over TDM (E1/ T1) inter-faces and move to Abis over IP/Ethernet in Flexi Multiradio BTS with a new plug-in card (FIQA, FIYA) without changing the HW. The Abis over IP/Ethernet interface is an appli-cation SW product and under licence control. The Flexi Multiradio BTS IP/Ethernet inter-faces are controlled by a capacity licence.

PWE overviewA Pseudowire (PW) is a point-to-point connection between a pair of provider edge (PE) devices. Pseudowire Emulation (PWE) provides the transparent transport of a TDM signal (E1 or T1) via a packet-switched network (IP/Ethernet/UDP). PWE according to the Circuit Emulated Services over Packet Switched Network (CESoPSN) standard is supported. Physically, the PE function is realized by a new PWE plug-in type (FIQA or FIYA) inserted into the System Module. The PWE plug-in is controlled by the SW running on the System Module. The PWE system itself consists of the 2G Flexi BTS Site Manager, the BTS SW and the PWE PIU (PWE HW).

Figure 17 PW network topology

In addition to the 3 Ethernet interfaces, the PWE PIUs provide 4 external E1/T1 (FIQA) or 4 external E1 (FIYA) interfaces. During commissioning, the BTS can be configured to run either in TDM or PW mode. The E1/T1, available in the TDM mode, are used for the transport of E1 or T1 signals, whereas the Ethernet interfaces, available in the PW mode, are used for the transport of PW packets. Up to 8 PWs can be used in the PW mode. Each PW has the capacity of 31 time slots.

For more information on PW, see Appendix PW configuration parameters in the Com-missioning Flexi Multiradio BTS GSM/EDGE document.

PWE at 2G Flexi BTS Site ManagerThe 2G Flexi BTS Site Manager provides the following support for the PWE:

• Commissioning of the PWE PIU in PWE/TDM mode. • Fetching the PWE status and performance statistics during commissioning. • Configuration of the Ethernet port (EIF1, EIF3 for SFP). • Configuration of the PWE tunnel. • Synchronization settings. • Configuration of the Pseudowires. • Fetching performance statistics. • Fetching ARP table entries. • Monitoring the statistics and sending PWE configuration parameters before sending

the SCF during commissioning.

DN0967559 Issue 01A99


Id:0900d8058076d113

• Modifying the PWE configuration parameters after sending the SCF during commis-sioning.

• Changing the PWE settings through Q1 commands.

EthernetAccess to an Ethernet network is required for the physical transport of PW packets. The PWE PIU has three Ethernet interfaces: 2 Fast Ethernet (EIF1, EIF2) and one Gigabit Ethernet interface (EIF3 for SFP). In the PW mode, all interfaces can be used. By default, the Fast Ethernet interface EIF1 is in use. 1000 Base-LX and 1000 Base-SX SFP transceiver types are supported for Gigabit Ethernet. The user can hot replace the SFP transceiver. To change from the TDM to the PW mode requires un-commissioning with the removal of bypass capacity. A single VLAN is supported. All Ethernet traffic gen-erated uses the specified VLAN; this includes for instance ARP packets. The VLAN priority bits are configurable.

PWE configurationA Pseudowire packet is constructed by putting the selected time slots of TDM frame data with a CES header to a UDP packet which is then sent via Ethernet. The PW payload will collect the selected time slots of a configurable number of frames. One time slot occupies exactly one byte. The maximum PW payload size is 512 bytes. With padding in FE and full duplex in Gigabit Ethernet, the minimum restriction on payload is 1 byte, in order to avoid empty PW packets.

Tunnels are used for network layer connectivity over an IP network. Within each PW tunnel, one or up to eight PWs can be transmitted. One local IP address for PW system and one remote IP address per PSN tunnel can be configured. A gateway IP address is only needed in case the PW tunnel destination is at the Ethernet domain different from the connected domain.

100DN0967559 Issue 01A


Id:0900d8058076d116

8.4 BSS10045 Dynamic Abis allocationDynamic Abis provides an efficient transport mechanism for GPRS and EGPRS to use more than one 16 kbps sub channel on the Abis interface for each packet data channel (PDCH) on the Air interface. The continuous areas of PCM timeslots on PCM links are configured as Dynamic Abis pools (DAPs) to provide the needed capacity.

The logical TRX utilizing Dynamic Abis is associated with a DAP in addition to the standard fixed traffic channel (TCH) area. Any packet data channel would be continu-ously using a master PCU channel located on a fixed area. Depending on the traffic load on each Air interface channel, more capacity would be allocated from the DAP. See the table below for the number of 16 kbps DAP sub channels used with each CS and MCS.

The PCU controls the downlink and uplink slave allocation on a radio block basis. Any 20 ms period on Abis is controlled based on real traffic demand. Downlink and uplink allocations are controlled separately. The slave allocation is informed to the BTS by in-band signaling on the corresponding downlink master channel.

Multiple logical TRXs can share a DAP. Multiple DAPs can be configured for each BTS and for each physical Abis link.

CS/MCS Number of DAP sub channels

CS1 0

CS2 1

CS3 1

CS4 1

MCS-1 0

MCS-2 1

MCS-3 1

MCS-4 1

MCS-5 1

MCS-6 2

MCS-7 3

MCS-8 4

MCS-9 4

Table 6 Number of 16 kbps DAP sub channels used with each CS and MCS

DN0967559 Issue 01A101


Id:0900d8058076d119

8.5 BSS5850 Satellite AbisSatellite Abis allows the use of satellite connections on the Abis interface between the BSC and the BTS. Satellite Abis enables you to create network coverage in areas where the coverage could not otherwise be implemented because of the limitation of the trans-mission media. Typically, these remote BTSs are used in low-capacity and temporary applications. The BTS software adapts to the satellite delay (max 280 ms in one direc-tion) and the BSC and BTS perform the necessary alignments. Note that satellite Abis restricts the BTS performance in higher capacity activities on CS and PS data. It is rec-ommended to configure the BTS so that a non-combined BCCH configured and a SDCCH/8 to the TCHs only TRX, whenever possible. It is also recommended to config-ure PS data so that high coding schemes are used only in one timeslot or that low coding schemes are used in multiple timeslots.

This feature is activated for each BSS individually. It is activated by an Abis_type param-eter switch in both the BSC and the BTS.

102DN0967559 Issue 01A


Id:0900d8058076d11c

8.6 BSS21497 Enhanced satellite supportNew IP-based satellite services with dynamic bandwidth allocation have delays up to 400 ms in one direction.

Documents

Rel. RG10(BSS) Operating Documentation - Sept 2010