Generation Roadmap for Cellular Telephony

Prepared by:MIHIR KUMBHAKARAGM(CMTS)Dated:10.03.07

Wireless technology is accelerating very fast.It is quickly moving into 1G,2G,2.5G,3G ,4G and NGN

1st Generation The first generation of mobile cellular telecommunications systems appeared in the 1980s.The first generation used analog transmission techniques for traffic, which was almost entirely voice.There was no dominant standard but several competing ones.

Such as Nordic Mobile Telephone (NMT) used in Scandinavia,southern Europe etc It comes in two variations:o NMT-450o NMT-900 Total Access Communications System (TACS) used in UK,and middle Eastern countries.It uses 900MHz band. Advanced Mobile Phone Service (AMPS).- used in US,Australia,New Zealand.It uses 800MHz band

2nd Generation It has been introduced from the year 1992.It uses digital radio transmis-sion for traffic. The 2G networks have much higher capacity than the first-generation systems. GSM is by far the most successful and widely used 2G system. Data rate supported : 9.6kbps to 14.4 kbps It uses Circuit switching

There are several standards for 2G systems.such as-

#Global System for Mobile (GSM) communications-Designed and developed by a number of different organization working together. # code-division multiple access (CDMA) IS-95-Designed and developed by a single company,Qualcomm.v CDMA uses different codes to separate transmissions on the same frequency.v IS-95 is the only 2G CDMA standard so far to be operated commercially.v It is used in the United States, South Korea, Hong Kong, Japan, Singapore etc.

Generation 2.5

It has been introduced in the year 2000-2001

Generation 2.5 is a designation that broadly includes all advanced upgrades for the 2G networks

2.5G GSM system includes General Packet Radio Services (GPRS), and Enhanced Data Rates for Global Evolution (EDGE) in addition to the 2G systems. Data rate supported: depending on the coding scheme(CS) and the no. of time slots used( 1 up to 8)

It uses circuit switching and packet switching both

It supports the data rate up to 384 kbps

3rd Generation It has been introduced in the year 2001 as trial version

It supports the data rate up to 2 mbps

Evolution of GSM and CDMA has taken them as W-CDMA(UMTS) and CDMA-2000 in third generation.

It supports both circuit switching and packet switching

4th generation and NGN This technology is expected to arrive not before the year 2010 .

It will support the data rate up to 100 mbps.

Multimedia, mobile TV,mobile broadband wireless access etc will be possible because of its high band width.

It will support both circuit switching and packet switching

GSM Overview

>GSM stands for Global System for Mobile communication >GSM Technology is one of the different types of the wireless communication available in the world.

Frequency range-

*Uplink Frequency: 890 Mhz 915Mhz*Downlink Frequency: 935Mhz- 960Mhz.

Modulation Technique- GMSK

Speech is divided into 20 msec sample.Each 20ms sample is encoded using 260 bits.(That requires 13 kbps.) Band width:each radio channel in the GSM system has a frequency bandwidth of 200khz.

Number of Channels:124 radio channel.

GSM Network

Basic GSM Network consist of MS,BSS&NSSMS carried by the subscriber It consists of *ME-mobile equipment ,hand portable or vehicle mounted unit. *SIM- Subscriber identity module ,it contains the entire customer related information (identification,secret key for authentication etc)

BSSBSS- Controls radio link with mobile station.

It consists of BTS (Base transreceiver Station)-It defines a cell and is responsible to establish the radio link control protocol with MS.BSC(Base Station Controller)-Controls multiple BTSs and manages radio channel set up and handovers.BSC is the connection between BTS and the MSCs.

NSSNetwork & Switching Subsystem(NSS)-Mobility management and Switching of calls between mobile users and between mobile and fixed network users.

It consists of : MSC- is the central component of the NSS.Operates all switching functions for mobiles within its jurisdiction.Interfaces with mobile and other (Including fixed) networks.Manages the location of mobile

ContinuedSwitches calls Manages security features.Controls hand over between BSCsResources managementInterworks with and manages network database.Collect call billing data and sends to Billing center.Collects traffic statistics for performance monitoring.

Continued..HLR-Contains all subscriber information for the purposes of call control and location determination.

VLR- is only a temporary storage while the particular subscriber is located in the geographical area controlled by the MSC/VLR.

AUC- Is a protected database that stores the security information for each subscriber.(A copy of the secret key is stored in the SIM)

ContinuedEIR-It contains three list of IMEI number.

White list.-Valid mobile equipment in the network Grey list.- Suspected numbers Black list-Totally barred.

Logical ChannelsFive types of logical channels:

1.Traffic Channels* TCH - Used to carry traffic.2.Broadcast channels.*BCCH-used to carry signaling and control info* FCCH-used to correct the frequency of Mobile* SCH- used for synchronization of the base station3.common control channels*PCH-used to page the mobile*AGCH-used to access the signaling channel*RACH-used by MS to request for signaling channel4.Dedicated Control Channels*SDCCH-used as signaling channel*SACCH-used to carry measurement reports*FACCH-used during handover5.CellBroad cast channel*CBCH-used to broadcast short messages in cells

MSISDNThe only important number for a user of GSM is the phone number i.e.MSISDN.

The MSISDN follows the ITU-T standard E.164 for addresses as it is also used in fixed ISDN networks.

This number consists of the country code(cc) ( 91 for India),the national destination code(NDC) (the address of the network provider ; e.,g., 9434 for BSNL WB) and the subscriber number (SN) .

IMSIGSM uses the IMSI for internal unique identification of a subscriber.

The IMSI follows the ITU-T standard E.212 Number series.

IMSI consists of mobile country code (MCC) (e.g.,404 for India),the mobile network code(MNC) (i.e.,code of the HLR; e.g.,74 of BSNL WB),and finally the mobile subscriber identification number(MSIN).

Location Updating (LU)When the LU request is received by the new VLR,authentication is performed.

If authentication is successful,the VLR checks its database to determine whether it has a record for this MS-subscription.

When VLR finds no record for the MS,it sends a request to the subscribers HLR for a copy of the MS-subscription.

The HLR passes the information to the VLR and updates its location information for the subs.The HLR instructs the old VLR to delete the information it has about the MS- subscription.

Inbound Roamer registration - Location Update-Diagram1. UpLoc1. UpLoc1. UpLoc WB BSNL3. ISD_respUKSCCP CdPA: 44-181-123456(MGT derived from IMSIS analysis)CgPA:919434099995(VLR)

MAPIMSI: 234-15-123456MSC/VLR:919434099995

SCCP CdPA: 44-181-HLRUKCgPA: 919434099995(VLR1)3. ISD_resp2. ISD 4. UPL_resp

SCCPCdPA: 919434099995(VLR) CgPA: 44-181-HLRofUK1

MAPIMSI: 234-15-123456MSISDN: 44-181-6543212.ISD2.ISD4. UPL_resp

Call from an MS(MO Calls)The MS uses RACH to ask for a signaling channel.

The BSC/TRC allocates a signaling channel,using AGCH.

The MS sends a call set-up request via SDCCH to the MSC/VLR.Over SDCCH all signaling preceding a call takes place (e.g.,authentication, ciphering,sending B-subscribers number,checking of o/g barring parameter etc.).

MO CALL Continued..The MSC/VLR instructs the BSC/TRC to allocate an idle TCH.The RBS and MS are told to tune to the TCH.

The MSC/VLR forwards the B-number to an exchange in the PSTN,which establishes a connection to the subscriber.

If the B-subscriber answers,the connection is established.

Call to an MS (MT Calls)The PSTN subscriber dials in the MSs telephone number (MSISDN).The MSISDN is analyzed in the PSTN,which identifies that this is a call to a mobile network subscriber.A connection is established to the MSs home GMSC.

The GMSC analyzes the MSISDN to find out which HLR the MS is registered in,and queries the HLR for information about how to route the call to the serving MSC/VLR.

The HLR translates MSISDN into IMSI,and determines which MSC/VLR is currently serving the MS.

MT Calls continued..The HLR requests an MSRN from the serving MSC/VLR.The MSC/VLR returns an MSRN via HLR to the GMSC.

The GMSC analyses the MSRN and routes the call to the MSC/VLR.

The MSC/VLR knows which LA the MS is located in.A paging message is sent to the BSCs controlling the LA.

The BSCs distribute the paging message to the RBSs in the desired LA.

MT Calls continued..The RBSs transmit the message over the air interface using PCH with IMSI/TMSI.

When the MS detects the paging message,it sends a requests on RACH for a SDCCH.

The BSC provides a SDCCH,using AGCH.

SDCCH is used for the call set-up procedures.Over the SDCCH all signaling preceding takes place.

The MSC/VLR instructs the BSC/TRC to allocate an idle TCH.The RBS and MS are told to tune to the TCH.The mobile phone rings.If subscriber answers,the connection is established.

Call to an MS(MT Calls) in Roaming-DiagramWB BSNLUK 44-181-123456PSTNDIALSIAM1.SRI2.PRN2.PRN2.PRNMSISDNIMSI2.PRN3.PRN ACK3.PRN ACK3.PRN ACK3.PRN ACKMSRNMSRN4.SRI ACK

MSRN5.ISUP IAM5.ISUP IAM5.ISUP IAM6.PAGING6.ACM6.ACM6.ACM7.ANM7.ANM7.ANM8.Disconnect8.REL8.REL9.REL ACK9.REL ACK9.REL ACK

MO SMS -DiagramWB BSNLUKSCCP CdPA: 44-181-123456(MGT derived from IMSIS analysis)CgPA:919434099995(VLR)

MAPIMSI: 234-15-123456

SCCPCdPA: 919434099995(VLR) CgPA: 44-181-HLRofUK1

MO -FSMMO -FSMSMSCMO-FSM-RSPMO -FSMMO-FSM-RSPMO-FSM-RSPAn MS establishes a connection to the network,

as in the normal call set-up.The MS sends the short message using SDCCH to the

SMSC via MSC/VLR.The SMSC in turn forwards the short message to its destination.

MT SMSA user sends a message to a SMSC.

The SMSC sends the message to the SMS-GMSC.

The SMS-GMSC queries the HLR for routing information.

The HLR returns routing information to the SMS-GMSC.

The SMS-GMSC reroutes the message to the MSC/VLR.

The MS is paged and a connection is set up between the MS and the network,as in the normal call set-up case.

MT SMS Continued

The MSC/VLR delivers the message to the MS.Short messages are transmitted on SDCCH.

If the delivery was successful,a report is sent from the MSC/VLR to the SMSC,if not,the HLR is informed by the MSC/VLR, and a failure report is sent to SMSC.

The HLR then informs the SMSC when the MS becomes available.

MT SMS -DiagramWB BSNL-Circle1UK

SMSC SMSCdPA:44-181-123456SCCP CdPA: 44-181-SMSCofUK1CgPA:919434099995(MSC/VLR) SCCP CdPA: 91-9434099995 MSC/VLRCgPA: 44-181-SMSCofUK11. MT-FSM1. MT-FSM1.MT- FSM1. MT-FSM5. MT-FSM_resp5. MT-FSM_resp5. MT-FSM_respSRI-SMSRI-SM ACK

PREPAID SYSTEMPrepaid system adds few other nodes than the existing GSM network.

It is the IN system which handles the prepaid subscriber.

IN system consist of Mainly

1.SCF2.SDP3.PPAS4.IVR

In MSC SSF module handles the prepaid call Scenario in MSC side.

GPRSGPRS Core network consists of

SGSN:Serving GPRS Support Node; the gateway between the RNC and the core network in a GPRS/UMTS network

GGSN:Gateway GPRS Support Node; the gateway between a cellular network and a IP network.

GPRS RELATED LINKSGc-The interface between the GGSN and the HLR in a GSM/GPRS network

Gd-The interface between the SGSN and the SMSC in a GSM/GPRS

networkGf-The interface between the SGSN and the EIR in a GSM/GPRS network

Gi-The interface between the GGSN and the Internet in a GPRS network

Gn-The interface between the GGSN and the SGSN in a GPRS network

Gp-The interfaces between the GGSN/SGSN and the Border Gateway in a

GPRS networkGr-The interface between the SGSN and the HLR in a GPRS network

Gs-The interface between the SGSN and the MSC in a GSM/GPRS network

GPRS ATTACHSGSNEIRHLR1.GPRS ATTACH REQUEST2.Authentication request3.Athentication res4.Equipment identity check5.Equipment idemtity check response6.update location7.ISD8.ISD ACK9.GPRS attach accepted

PDP Context activationSGSNDNS SERVERGGSNRadius ServerDHCPSERVER

1.Activate PDP contest2.DNS query (APN)3.DNS Resp(GGSNIP ADR4.Create PDP Contest req.5.Radius authentication request6.Res7.DHCPADDR.REQ8.DHCPADDR.RES9. Create PDP Context Response

10. Activate PDP Context Accept

CDMA (IS-95) TECHNOLOGY Code-Division Multiple Access, a digital cellular technology that uses spread-spectrum techniques

IS-95 CDMA system operates in 800 Mhz

CdmaOne is the brand name of IS-95 technology from 1997.CdmaOne is basically an air-interface standard.

IS-95 uses Frequency division duplex.Forward link and reverse link transmission occur in different frequency band.

Duplex separation used in IS-95 is 45Mhz

Carrier spacing is 1.25 Mhz

Forward link frequency: 824-849Mhz

Reverse Link frequency: 869Mhz-894Mhz

The forward link consists of Base station(BS) transmitter,radio channel and the MS receiver.

CDMA ContinuesCdmaOne system supports four different types of forward channels

#Pilot channel-is continuously transmitted by each CDMA carrier and is used by MS to identify the BS and to asses the suitability of the cell hand over.In this respect it may be likened to the BCCH carrier in GSM system.

#Synchronous channel-It allows MS to achieve time synchronization with BS and the network .

#Paging channel-is used to page MSs to alert them to an incoming call.

#Traffic channel-are assigned to the users as required and they may carry speech or user data at bit rates of up to 9.6 kbps.

Each forward channel on a CDMA carrier is assigned a different 64-bit Walsh code.

The reverse link radio path consists of the Mobile station(MS) transmitter,the radio channel and the base station(BS).

CdmaOne system supports two different types of radio channel on reverse link

#Access channel-as its name would suggest,is used by MS initially to access the network,e.g. at call initiation or in response to a paging message.Each Base Station may support 32 access channels per forward link paging channel and the MSs within a CeLL are pseudo-randomly distributed between the access channels.

CDMA ContinuesAccess channel data are presented in the form of one 96-bit frame every 20 ms.Of this 96 bits,88 are used to carry information and remaing eight are encoder tail bits.

# Traffic channel-are assigned to the individual user as required.A reverse link traffic channel may carry speech and data at bit rates up to 9.6 kbps.

The cdmaOne MS does not transmit a pilot signal as this would significantly decrease reverse link capacity.

BS receiver uses RAKE receiver to demodulate the reverse link signal from a particular MS.

MS handover process occur by measuring the strength of the pilot channels signal from a BS other than its current BS.

CdmaOne system supports three main types of handover

CDMA Continues # Idle mode handover-It occurs when an MS moves from the coverage area of one BS into the coverage area of a second BS while an MS is an idle mode.

# Soft handover- is used between BSs having CDMA carriers with identical frequency assignments.

# Hard handover- occur when a mobile is switched between two BSs using different carriers.

Simplified data flow for the access procedure of a mobile terminated call.

Basic cdmaOne diagram

CDMA 2000 This is the evaluated 3G version of IS-95/cdmaOne technology.

CDMA2000 is an ITU-approved standard that was the first 3G technologies (October,2000).

provides advanced voice communications and high-speed data connectivity, including access to the Internet, mobile data applications and multimedia content.

Supports data services at minimum transmission rates of 144 kbps in mobile (outdoor) and 2 Mbps in fixed (indoor) environments.

The world's first 3G commercial system was launched by SK Telecom (South Korea) in October 2000 using CDMA2000

CDMA2000 represents a family of standards and includes>CDMA2000 1X>CDMA2000 1xEV-DO Technologies >CDMA2000 1xEV-DO Rev A>CDMA2000 1xEV-DO Rev B>Ultra Mobile Broadband - UMB (CDMA2000 1xEV-DO Rev C)

CDMA 2000 continues CDMA2000 builds on the inherent advantages of CDMA technologies,such as

>introduction of Orthogonal Frequency Division Multiplexing (OFDM and OFDMA)

>advanced control and signaling mechanisms

>improved interference management techniques end-to-end Quality of Service (QoS)

>new antenna techniques such as Multiple Inputs Multiple Outputs (MIMO) and Space Division Multiple Access (SDMA) to increase data throughput rates and quality of service >improving network capacity and reducing delivery cost.

CDMA2000 Advantages: >Superior Voice quality

>High-Speed Broadband Data connectivity

>Increased Voice and Data Throughput capacity

>Long-Term, Robust and Evolutionary Migration Path with Forward and Backward Compatibility

>Differentiated Value-Added Services such as VoIP, PTT, Multicasting, Position Location, etc.

>Flexible Network Architecture with connectivity to ANSI-41, GSM-MAP and IP-based Networks and flexible Backhaul Connectivity

>Flexible Spectrum Allocations with Excellent Propagation Characteristics

>Robust Link Budget for Extended Coverage and Increased Data Throughputs at the Cell Edge

>Improved Security and Privacy

CDMA 2000 NETWORK DIAGRAM

UMTS/WCDMA

UMTS (WCDMA)is a 3G evolution of GSM and GPRS

UMTS is one of the Third Generation (3G) mobile systems being developed within the ITU's IMT-2000 framework

The coverage will be provided by a combination of cell sizes ranging from 'in building' Pico Cells to Global Cells provided by satellite, giving service to the remote regions of the world

created a platform to converge the worlds of speech, data services and the Internet to create a global market for mobile multimedia.

UMTS is designed to increase a subscribers data rates and system capacity.

Technical Features: Modulation Techniques used QPSK

Multiple access technology used as CDMA

Frequency reuse pattern : 1*1 (cell*sector)

Maximum data rates supported: 384kbps to 2 mbps

Both packect switch and circuit switch are supported

Radio channels are 5MHz wide

Chip(fundamental unit of transmission in a CDMA system) rate of 3.84 Mcps

Supports two basic modes of duplex, frequency division and time division. Current systems use frequency division, one frequency for uplink and one for downlink. For time division, UMTS uses 15 slots per radio frame.

Technical Features continues . >Employs coherent detection on uplink and downlink based on the use of pilot symbols

> Supports inter-cell asynchronous operation

>Variable mission on a 10 ms frame basis

>Adaptive power control

> Multiuser detection and smart antennas can be used to increase capacity and coverage.

>initially poor coverage due to the time it takes to build a network

>for fully fledged UMTS incorporating Video on Demand features, one base station needs to be set up every 11.5 km (0.620.93 mi). While this is economically feasible in urban areas, it is infeasible in less populated suburban and rural areas.

>Requires huge frequency spectrum

UMTS Network Architechture

UMTS Network ArchitechtureUMTS core network architechturally a GSM phase 2+Core network that is power up so that it can also handle the higher volume,higher bit rate,UMTS traffic.

RNS(Radio network subsystem) is the additional part for UMTS network than GSM Phase 2 + network.

RNS consists of RNC (Radio network Controller) and Node B(part of User Equipment and Base station)

The UMTS terrestrial Radio interface(UTRA) frequency duplex(FDD) mode is the W-CDMA radio interface of the UMTS.

Carrier frequency is defined by the UTRA absolute radio frequency channel number(UARFCN).

Physical Channels there are two basic types of physical channels. # Dedicated Channels-These are used by UEs for the duration of the call.There are two Dedicated channels->PCCH-Dedicated physical control channel carries physical layer control information >DPDCH-Dedicated physical data channel transports the user traffic.

#Common channels-these are used to carry information to the UEs within a cell and are used by the UEs to access the network. Common channels are of two types: Common channels are of two types: 1. Down link common channels 2. Uplink common channels

Down link common channelsCPICH-Common Pilot Channel provides a common demodulation reference over all or part of a cell.

P-CCPCH-Primary common control physical channel caries general network information.

S-CCPCH-Secondary common control physical channel is used for paging and packet data

SCH-Synchronisation channel is used by UE for its initial cell search

AICH-Acquisition indication channel controls the use of common uplink channels.

UP Link common physical channels PRACH-Physical Random Access Channels used by UEs initially to access the network

PC-PCH-Physical Common Packet Channel allows bursts of data to be transferred from UEs to the network.CPCH is typically used for short,infrequent burst of data where as dedicated channels are more suited to long burst.

UMTS Frame structureThe duration of a frame is 10ms

One frame contains 15 slots

Each slot duration =0.667 ms

Each slot contains 2560 chips

Chip rate=3.838Mchips/s

One super frame =72 frame= 720ms duration

Difference between CDMA2000 and UMTS technology>Cdma2000 and UMTS were developed separately and are 2 separate ITU approved 3G standards

>cdma2000 were developed to be backward compatible with cdmaOne but UMTS phones are not meant to be backward compatible with GSM systems.

>Cdma2000 is easy to implement because operators do not need new frequencies but implementation of UMTS is very difficult because of its new requirement of wide range of frequency and new implementation of the radio access network.

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