NODE B of 3G Mobile Network

8/10/2019 NODE B of 3G Mobile Network

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GSM NODE B OF 3G MOBILE NETWORK

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rM AlSzEngineering Instructions onNODE B of 3G Mobile Network

msZ xZrDocument No. : EI/GSM/NODE B/10-11/ 60 mxZrNo of Pages. : 13 e AU M xSpGR reference : GR No. GR/UTR-01/01 JUNE 2005

xv|kl qM rS MD)AmendmentNo. (If any)

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m xv|ki Page Nos. Amended : NIL eUMiIssued By : Telecom Quality Assurance circle, Bangalore AlqSiApproved by : The CGM, TQA circle, Bangalore

eU MUl M SlMDate of Issue : 31-03-2011Written by : B G VENKATRAM (QA Circle)Expert Comments : SUDHIR BELLUBBI (Karnataka Circle)

Restricted use by BSNL Employees only

All efforts have been made to incorporate all relevant up to date information available, any discrepanciesor need for addition or deletion is felt necessarily may please be intimated to this office for furtherimprovement,on E-Mail Id cgmtqa_ei@ bsnl.co.in (or) [email protected]

DISCLAIMER: FOR INTERNAL CIRCULATION AMONG BSNL EMPLOYEES AS A GUIDELINE FORINSTRUCTIONAL PURPOSE.

Office of Chief General ManagerTelecom Quality Assurance circle

II Floor, Sanchar Complex,BSNL-WMS Compound, 9 th Main,

Jayanagar 5 th Block, Bangalore - 560 041Tel: 91 80 26533100 Fax: 91 80

26530681Visit us at www.qa.bsnl.co.in

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CONTENTS

Description Page No.Scope 3Introduction 3Functions of Node B 4Differences between GSM BTS & Node B 4Key Components 5Features 53G Services supported 5Macro Node B configurations 5Node B specifications 5

Types 6

IP Connectivity to Node B 6 Transformation to eNode B 7Precautions during installation 8

Tests 8FAQs 8Feedback Contact person 12Abbreviations 12References 13


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Six Sector Node B

Increasing the coverage area

The UTRAN will support six, sectored sites, which could maximize coverage and capacity ofUMTS sites. The basic principle is that by using six narrow beam antennas, the coverage area ofa cell will be extended due to the increased forward gain, and the capacity will be double that ofa three-sectored cell. The use of six sectors can lead to an increase in the coverage area that isserved by multiple cells (i.e. the soft handover region), depending on the local propagationconditions and the antenna pattern. The two figures show the overlap between the antenna

patterns. This does not match the soft handover regions, but is shows, how the overlap canincrease, given certain antenna beamwidths.

Fig. UMTS Architecture


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Functions of Node B

Traditionally, the Node Bs have minimum functionality, and are controlledby an RNC (Radio Network Controller).

The functions of Node-B are: Air interface Transmission / Reception Modulation / Demodulation CDMA Physical Channel coding Micro Diversity Error Handling Closed loop power control

However, this is changing with the emergence of High Speed Downlink PacketAccess (HSDPA), where some logic (e.g. retransmission) is handled on the Node B forlower response times.

Differences between GSM BTS and Node B of UMTS

Parameter GSM BTS Node BController BTSs are controlled by BSC Node Bs are controlled by RNCFrequencyuse

2G, GSM cells are assigned withmultiple frequencies ( f 1 - f 6)which have corresponding RadioBase Stations (BTSs). The groupof frequencies can be reused inother cells, provided that thesame frequencies are not reusedin adjacent neighboring cells asthat would cause Co-channelInterference.

The utilization of WCDMA technologyallows cells belonging to the same ordifferent Node Bs and even controlled bydifferent RNC to overlap and still use thesame frequency (in fact, the wholenetwork can be implemented with justone frequency pair).

Cell Radius As GSM operates at lowerfrequencies 900MHz, the cellradius is larger, and the pathloss is frequency dependant.

As WCDMA operates at higher frequencies2100MHz, the cell radius is smaller, andthe path loss is frequency dependant.

Cell Size The cells' size is almostconstant. This requires a lessernumber of BTSs.

The cells' size is not constant (aphenomenon known as "cell breathing").

This requires a larger number of Node Bsand thus careful planning in 3G (UMTS)networks.

Power Power requirements on BTSsand user equipment (UE) arehigher.

Power requirements on Node Bs and userequipment (UE) are comparatively muchlower.

Interfaces On E1 Links between BTS andBSC

On 8 E1 Links/STM-1 Link between NodeB and RNC and also IP port.

Sectors Supports three sectors Supports up to six sectors


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Macro Node B Indoor Macro Node B Outdoor Micro Node BPico

Node B

Key Components of Node B

A completely setup Node B contains a cabinet, an antenna mast and actual antenna. The Cabinet contains the equipment for transmitting and receiving radio signals(transceivers) and equipment for encrypting and decrypting communications with theBase Station Controller (BSC). What you can see by the side of a road or in a city centeris just an antenna. However, the tendency nowadays is to camouflage the antenna(paint it the color of the building or put it into an RF-transparent enclosure). Smallerindoor solutions may have a built-in antenna on the cabinet door).

Features of Node B

Scalable capacity High Power MCPA Pooled base band capacity with minimum 128 Channel elements HSDPA Hardware readiness Receiver diversity MHA/TMA support

Support of Outdoor version without the need of external air-conditioning and shelter

3G Services supported by Node B

Node B supports simultaneous use of Voice/Video Telephony, High-speedMobile Internet, and UMS 3G services. Unified Messaging System (UMS) is theintegration of different electronic messaging and communications media (E-mail, SMS,


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Fax, voicemail, video messaging, etc.) technologies into a single interface, accessiblefrom a variety of different devices.

Macro Node B Configurations

i. OMNI one carrierii. 3 Sector, with 1 Carrier per sector upgradable to 2 carriers per sector

iii. 4 - 6 Sector, with 1 carrier per sector upgradable to 2 carriers per sector

Node B Specifications

Frequency Range

FDD mode air interface to 3GPP compliant Downlink frequency band: asallocated WPC/DoT for UMTS services in India including the following:

i. Downlink: 2110 MHz - 2170 MHz; Uplink: 1920MHz - 1980 MHz

Total UMTS Bandwidth: 60 MHz, 5 MHz Channel Bandwidth The frequency bands of GSM are:

i. Downlink: 935 MHz - 960 MHz; Uplink: 890MHz - 915 MHzii. Downlink: 1805 MHz - 1880 MHz; Uplink: 1710MHz - 1785 MHz

Total GSM Bandwidth: 25 MHz, 124 Channels, 200 KHz ChannelBandwidth

Receiver Sensitivity

Minimum requirement of Receiver Sensitivity, measured at the antenna port of

Node B top:

Sensitivity of Node B without diversity -123 dBmSensitivity of Node B with 2 ways RX diversity -125 dBm

Transmit RF Specifications

MCPA with Minimum Output power per sector: 43dBm measured at antennaport at Node B top

Backhauli. The System support up to 8 Els

ii. The system support integrated transmission interface to DMWradio/ STM-l

IP Connectivity to Node B

Eventually IP/MPLS will become the transport technology. The interface at theNode B is E1, which is aggregated to Ethernet and transported to RNC via IP/MPLSnetwork.


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The simplified IP network topology provides a higher degree of stability andavailability. Improved and accelerated maintenance and fault isolation will be visible.

Fig. IP connectivity to Node B

Transformation of Node B to eNode B

The transformation from 2G GSM BTS to 3G UMTS Node B to 4G LTE eNode Bhas made the Base Station from passive network element to active network element.

3G Node B 4G eNode B

S1S1

X2

SAE/LTE

SAE-GW

Core

RAN

eNB eNB

MME

S1S1

X2

SAE/LTE

SAE-GW

Core

RAN

eNB eNBeNBeNB eNBeNB

MME

The new base station is more complicated than the Node B inWCDMA/HSPA radio access networks, and is consequently called eNB (EnhancedNode B).


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SAE architecture is the Evolved Packet Core (EPC ), also known as SAE Core .

The EPC will serve as equivalent of GPRS networks (via the MobilityManagement Entity , Serving Gateway and PDN Gateway subcomponents).

Precautions during installation

The AC power distribution shall be adequately protected using surge arrestors,contactors, circuit breakers etc. which shall ensure protection of the Node-B in case ofexternal fluctuations and surges.

The outdoor enclosure shall be supported with an External Battery Backup thatshall ensure 8-Hour backup in case of power failure.

The rectifiers housed in the Node B Outdoor enclosure shall support theexternal batteries Bank, and also be equipped with Low Voltage Disconnect (LVD)

contactors.Instructions including Tests like QM 333 etc.

The Environmental test conditions as per QM-333 of BSNL are:Indoor Node B - Category AOutdoor Node B - Category D along with conformance to IP 56

FAQs

1. How planning for Node Bs is done?

The planning for Node B is derived from air interface capacity and coveragecalculations. Hardware configuration is vendor specific, but here is a general list ofthings that need to be considered when planning Node Bs:

Call mix of expected traffic Type of Node Bs (Outdoor / Indoor) Amount of low capacity Node Bs Required redundancies (e.g. 2N, N+1) Required Receiver diversities Number of carriers per sector Number of sectors per Node B Number of users Voice and data traffic to be carried Node B software features Required Node B optional features Requirements for special antenna systems Requirements for power and transmission systems


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2. What are the factors for optimization in Node B ?

The main important aspects of optimization are coverage and capacity. Many issuesthat are resolved by optimization are cell breathing, near and far problem, around thecorner problem, hand over, pilot pollution and incomplete neighbour list. Dependingon specific network requirements, optimization helps in to maximise its coverage vicecapacity during the early stage green field network and increase capacity in denseurban areas. These factors help in reducing call drops, origination failures andtermination failures.

3. What is Soft Handover?

A soft handover is one in which the channel in the source cell is retainedand used for a while in parallel with the channel in the target cell. Soft handoversmay involve using connections to more than two cells, e.g. connections to three, fouror more cells can be maintained by one phone at the same time.

4. What is Hard Handover?

A hard handover is one in which the channel in the source cell is releasedand only then the channel in the target cell is engaged . Hard handovers areintended to be instantaneous in order to minimize the disruption to the call. A hardhandover is perceived by network engineers as an event during the call.

5. What is the difference between GSM and UMTS handover?

A big difference between a TDMA-based GSM system and a CDMA-based UMTSsystem is how the phone deals with handing off from one cell site to another. In

TDMA-based systems the phone must wholeheartedly switch from one channel toanother in order to switch towers. There are no halfway measures here, its all ornothing. As a result, all TDMA-based GSM phones suffer from slight (but ratherannoying) interruptions in the audio stream whenever a handoff occurs, and if onedoesnt occur in a timely fashion, the user can experience rather devastatingdegradation of the call quality.

In a CDMA-based system all callers and all cell sites operate on the samefrequency . The calls are separated by the magic of encoding differences that can besorted out by the receiver. For this reason handoffs can be achieved without using anall-or-nothing approach. A phone can gently shift from one tower to the next byselectively receiving the data stream from multiple sites simultaneous. Subsequentlyhandoffs are not audible.

However, there is a price to be paid for this approach. In order to CDMA tofunction correctly, each and every phone on the network must be operating just a hairabove the noise floor. To prevent them from occasionally falling through the noisefloor, rapid corrections in transmit power must be made. The concept worksexceptionally well in practice, but occasional bouts of frame errors do occur, and sowhile CDMA doesnt have the interruptions from handoffs, it does offer its own unique


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type of audio problems. However, the overall effect on a conversation is markedly lessannoying in a CDMA system than in the current TDMA system employed by GSM.

6. What is WCDMA?

W-CDMA (Wideband Code Division Multiple Access), UMTS-FDD, UTRA-FDD, orIMT-2000 CDMA Direct Spread is an air interface standard found in 3G mobiletelecommunications networks. It utilizes the DS-CDMA channel access method andthe FDD duplexing method to achieve higher speeds and support more userscompared to most time division multiple access (TDMA) schemes used today.

While not an evolutionary upgrade on the airside, it uses the same core networkas the 2G GSM networks deployed worldwide, allowing dual-mode operation alongwith GSM/EDGE; a feat it shares with other members of the UMTS family.

7. What is the difference between UMTS and HSDPA?

High-Speed Downlink Packet Access (HSDPA) is an enhanced 3G (thirdgeneration) mobile telephony communications protocol in the High-Speed PacketAccess (HSPA) family, also dubbed 3.5G, 3G+ or turbo 3G, which allows networksbased on Universal Mobile Telecommunications System (UMTS) to have higher datatransfer speeds and capacity. Current HSDPA deployments support down-link speedsof 1.8, 3.6, 7.2 and 14.4 Megabits/s.

8. What is HSPA+?

HSPA+, also known as Evolved High-Speed Packet Access is a wirelessbroadband standard defined in 3GPP release 7 and above. HSPA+ provides HSPA data

rates up to 84 Megabits per second (Mbit/s) on the downlink and 22 Mbit/s on theuplink through the use of a multiple-antenna technique known as MIMO (formultiple-input and multiple-output) and higher order modulation (64QAM).

9. What are the factors affect the 14.4 Mbps data rate?

Factors that reduce the practical maximum data rate are:

UE Capability/Category Number of Codes Inter-TTI Interval

Interval between consecutive assignments Depends on UE capability Allowed values are 1, 2, and 3

Retransmissions NAK sent 5 ms after block received Minimum retransmit time is 10 ms Can be identical or different redundancy version

ACK/NAK Repetition


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UE can be configured to repeat up to 4 times.

Disallows certain sub-frames for data transmission

10. What is the difference between GSM Um and UTRAN Uu interface?

The Um interface is the air interface for the GSM mobile telephone standard. Itis the interface between the Mobile Station (MS) and the Base Transceiver Station(BTS). It is called Um because it is the mobile analog to the U interface of ISDN. TheUm interface channels are:

Broadcast Control Channel (BCCH) Frequency Correction Channel(FCCH) Synchronisation Channel (SCH) Cell Broadcast Channel (CBCH)

Paging Channel (PCH) Access Grant Channel (AGCH) Random Access Channel (RACH) Standalone Dedicated Control Channel (SDCCH) Slow Associated Control Channel (SACCH) Fast Associated Channel (FACCH)

The Uu interface is the air interface for the UMTS mobile telephone standard. Itis the interface between the Mobile Station (MS) and the Node B. The Uu interfacechannels are:

Primary Common Control Physical Channel (PCCPCH), mapped to BCH

Secondary Common Control Physical Channel (SCCPCH), mapped to FACH,PCH Physical Random Access Channel (PRACH), mapped to RACH Dedicated Physical Data Channel (DPDCH), mapped to DCH Dedicated Physical Control Channel (DPCCH), mapped to DCH Physical Downlink Shared Channel (PDSCH), mapped to DSCH Physical Common Packet Channel (PCPCH), mapped to CPCH Synchronisation Channel (SCH) Common Pilot Channel (CPICH) Acquisition Indicator Channel (AICH) Paging Indication Channel (PICH) CPCH Status Indication Channel (CSICH)

Collision Detection/Channel Assignment Indication Channel (CD/CA-ICH)

11. What is a RRU and what are its advantages?

The traditional architecture of the radio infrastructure for cellular systems isbased on complete, stand-alone Base Stations, usually realized as fully indoorequipment, connected on one side to the aerial elements (typically represented by a


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single TX antenna plus two receive antennas to realize RX diversity), and on the otherside to the traffic network.

A Remote Radio Units (RRU), also called Remote Radio Heads (RRH), whichis placed on the Tower, near Antenna itself, is a single unit in which only the RF front-end functionalities are implemented. It is connected to the remaining basebandprocessing part Base Band Unit (BBU), which is placed indoor, through a bidirectionallink.

It greatly reduces the carriers requirement for site resources and theirinvestment and meanwhile improves the effect of coverage. In addition, it reducesfeeder line loss and supports the cell merge of different RF units, so it can be used inspecial situations where traditional technology cannot solve problems, for example,the coverage of high-speed railway and ultra-long distance.

The LTE architecture

The main philosophy behind LTE is minimizing the number of nodes. Thereforethe developers opted for single node architecture. The new base station is morecomplicated than the Node B in WCDMA/HSPA radio access networks, and isconsequently called eNB (Enhanced Node B). The eNBs have necessaryfunctionalities for LTE radio access network including the functions related to radioresource management.

Contrary to the WCDMA/HSPA UTRAN, the LTE UTRAN only has one nodetype: eNodeB. Thus, there is no equivalent node to and RNC for LTE. The eNodeBhas inherited most of the RNC functionality and hence more complicated thanthe NodeB. The eNodeB is incharge of single cell RRM decisions, handoverdecisions, scheduling of users in both uplink and downlink in its cells.

The eNodeB is connected to the core network using the S1 interface. The S1interface is a similar interface as the Iu interface. There is also an interface similar tothe Iur interface of WCDMA/HSPA, the X2 interface, which connects any eNodeB inthe network with any other eNodeB. The X2 in terface is mainly used to supportactive-mode mobility.


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Fig. LTE Architecture

The LTE specification uses the term Evolved UTRAN (E-UTRAN). In LTE,functionally the eNB (e-Node B) acts as Layer-2 bridge between UE and EPC. It is

responsible for the Radio Resource Management (RRM) and in addition has importantrole in Mobility Management.

Feedback Contact Person and website address

Sri. B. G. Venktram,DE(TSE-S), O/o CGM QA,

Jayanagar, Bangalore 41Phone: 080 26535100, 26961019Fax: 080 26530681Mobile: 09448451311Email: [email protected]

QA Website www.qa.bsnl.co.in

LIST OF ABBREVIATIONS

2G - Second Generation Wireless Telephone Technology3G - Third Generation Wireless Telephone TechnologyATM - Asynchronous Transfer ModeBTS - Base Transceiver StationCAMEL - Customised Applications for Mobile Network Enhanced LogicCSE - CAMEL Service EnvironmentDMW - Digital Microwave

E1 - E-carrier level 1 , wire technology with 2 Mbit/s data rateEPC - Evolved Packet CoreE-UTRAN - Evolved UTRANeNB - e Node B, Enhanced Node BFDD - Frequency Division DuplexingGGSN - Gateway GPRS Support NodeGMSC - Gateway Mobile Service Switching CentreGR - Generic RequirementGSM - Global System for Mobile communicationHLR - Home Location RegisterHSDPA - High Speed Downlink Packet AccessHSPA - High Speed Packet AccessHSS - Home Subscriber ServerIP 56 - IEC International Protection Rating for Outdoor Equipment EnclosureLTE - Long Term EvolutionLVD - Low Voltage DisconnectMCPA - Multi Carrier Power AmplifierMHA - Mast Head AmplifierMME - Mobility Management EntityMSC - Mobile Switching CentreOSA - Open Service Architecture


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PDN-GW - Packet Data Network GatewayQM - Quality ManualRAN - Radio Access NetworkRF - Radio FrequencyRNC - Radio Network ControllerRNS - Radio Network SubsystemRRH - Remote Radio HeadsRRM - Radio Resource ManagementRRU - Remote Radio UnitSAE - System Architecture EvolutionSGSN - Serving GPRS Support NodeSTM-1 - Synchronous Transfer Module Level-1 of bit rate 155.52 Mbits/s

TD - SCDMA - Time Division - Synchronous Code Division Multiple Access TEC - Telecommunication Engineering Centre TMA - Tower Mounted AmplifierUE - User EquipmentUMS - Unified Messaging SystemUMTS - Universal Mobile Telecommunication SystemUTRAN - UMTS Terrestrial Radio Access NetworkUm/Um - Radio interface between the mobile and Radio Access NetworkVLR - Visitor Location RegisterWCDMA - Wideband Code Division Multiple Access

Sources (References)

TEC GR of UTRAN No.GR/UTR-01/01 JUNE 2005www.en.wikipedia.orgwww.3gpp.orgwww.3g.co.uk

www.full-speed.orghttps://learningnetwork.cisco.com/index.jspawww.ti.com3G Evolution: HSPA and LTE for Mobile Broadband by Erik Dahlman

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NODE B of 3G Mobile Network