Generation Roadmap for Cellular Telephony. Prepared by: MIHIR KUMBHAKAR AGM(CMTS). Dated:10.03.07. Wireless technology is accelerating very fast. It is quickly moving into 1G,2G,2.5G,3G ,4G and NGN. 1 st Generation.
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Ø Nordic Mobile Telephone (NMT) – used in Scandinavia,southern Europe etc
It comes in two variations:
Ø Total Access Communications System (TACS) – used in UK,and middle Eastern countries.It uses 900MHz band.
Ø Advanced Mobile Phone Service (AMPS).- used in US,Australia,New Zealand.It uses 800MHz band
#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.
*Uplink Frequency: 890 Mhz –915Mhz
*Downlink Frequency: 935Mhz- 960Mhz.
MS –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)
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.
It consists of :
MSC- is the central component of the NSS.
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)
White list.-Valid mobile equipment in the network
Grey list.- Suspected numbers
Black list-Totally barred.
*TCH - Used to carry traffic.
*BCCH-used to carry signaling and control info
* FCCH-used to correct the frequency of Mobile
* SCH- used for synchronization of the base station
*PCH-used to page the mobile
*AGCH-used to access the signaling channel
*RACH-used by MS to request for signaling channel
*SDCCH-used as signaling channel
*SACCH-used to carry measurement reports
*FACCH-used during handover
5.CellBroad cast channel
*CBCH-used to broadcast short messages in cells
UK SubscriberInbound Roamer registration - Location Update-Diagram
(MGT derived from
UK SubscriberCall to an MS(MT Calls) in Roaming-Diagram
UK SubscriberMO SMS -Diagram
as in the normal call set-up.
SMSC via MSC/VLR.The SMSC in turn forwards the short
message to its destination.
(MGT derived from
5.Equipment idemtity check response
1.GPRS ATTACH REQUEST
4.Equipment identity check
9.GPRS attach accepted
5.Radius authentication request
2.DNS query (APN)
1.Activate PDP contest
10. Activate PDP Context Accept
4.Create PDP Contest req.
9. Create PDP Context Response
#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-Itallows 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.
#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.
Access 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.
#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.
>CDMA2000 1xEV-DO Technologies
>CDMA2000 1xEV-DO Rev A
>CDMA2000 1xEV-DO Rev B
>Ultra Mobile Broadband - UMB (CDMA2000 1xEV-DO Rev C)
>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)
>improving network capacity and reducing delivery cost.
>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 Spectrum Allocations with Excellent Propagation Characteristics
>Robust Link Budget for Extended Coverage and Increased Data Throughputs at the Cell Edge
>Improved Security and Privacy
>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.
>for fully fledged UMTS incorporating Video on Demand features, one base station needs to be set up every 1–1.5 km (0.62–0.93 mi). While this is economically feasible in urban areas, it is infeasible in less populated suburban and rural areas.
>Requires huge frequency spectrum
Ø UMTS 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.
Ø RNS(Radio network subsystem) is the additional part for UMTS network than GSM Phase 2 + network.
Ø RNS consists of RNC (Radio network Controller) and Node B(part of User Equipment and Base station)
Ø The UMTS terrestrial Radio interface(UTRA) frequency duplex(FDD) mode is the W-CDMA radio interface of the UMTS.
Ø Carrier frequency is defined by the UTRA absolute radio frequency channel number(UARFCN).
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
>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.