How Adaptive Multi-Rate Codec (AMR) work in GSM ?

Adaptive Multi-Rate (AMR) codec consists of a family of codecs (source andchannel codecs with different trade-off bit-rates) operating in the GSM FRand HR channels modes The AMR system exploits the…

Basic Work of MSC (Mobile Switching Centre)

Exchange where calls are established, maintained and released Database for all subscribers and their associated features. Communicates with the BSCs on the A interface and with PSTN on fixed line….

Advantages of Intelligent Network (IN)

Concept of Intelligent Network: The introduction of new services and access to the GSM service are based on the concept of Intelligent Network (IN). This is because of the independence…

Downlink Logical Channel in GSM

In 2G GSM Technology in forward direction Downlink (GSM BTS to GSM Mobile). There are mainly five Downlink Logical Channel in GSM. Frequency correction channel (FCCH) Synchronous channel (SCH) Broadcast…

Structure of Combined BCCH in GSM

It is used in the configuration of cells of low traffic density and small capacity. The Combined BCCH is only configured at timeslot 0. Channel combination: FCCH?SCH?BCCH?CCCH+SDCCH/4+SACCH/4 SDCCH/4: Stand-alone dedicated…

Structure of Main BCCH in GSM

The TDMA/FDMA multiplexing is used in GSM, the information needed in the synchronization between MS and BTS is provided by FCCH+SCH. The MS determines the frequency of the BCCH carrier…

Physical Combination of Logical Channel in GSM

As shown above, CCCH=PCH+RACH+AGCH; downlink CCCH=PCH+AGCH; and uplink CCCH=RACH. In the above combinations, combination 3 and 4 must be allocated to slot 0 of the BCCH carrier configured for the…

Uplink Logical Channel in GSM

1. Random access channel (RACH) It is an uplink channel used for MS randomly access to network by requesting for an SDCCH. The request includes a 3bit setup reason (call…

Logical Channel Type in GSM

As we know, every cell has several TRX and every TRX includes 8 timeslots (i.e. providing 8 basic physical channels). In the radio subsystem, the physical channel supports the logical…