How 26 and 51 Multiframes in GSM GSM is very complicated when we talk about its rf side and in it very complicated to understand the structure of 26 and 51 Multiframes, here my try to make you understand simply. The 26-frame Traffic Channel Multiframe in GSM The Below Figure shows the time relationship between … Read more
What is BSIC and its use in GSM BSIC=NCC+BCC In GSM system, each BTS is allocated with a color code, which is called BSIC. MS can identify two cells with the same BCCH by the help of BSIC. In network planning, effort should be made to make sure that BCCH of neighbor cells are different … Read more
BCH,CCCH and DCCH Channel of GSM BCH (Broadcast Channels) BCCH(Broadcast Control Channels) Downlink Only. Broadcast information of the serving cell (System Information). Transmitted on timeslot zero of BCCH carrier. Read only by idle mobile at least once every 30 secs. SCH (Synchronization Channels) Downlink Only Carries information for frame synchronization. Contains frame number and BSIC … Read more
Dedicated Control Channel (DCCH) in GSM SDCCH (Stand-alone Dedicated Control Channel) Uplink and Downlink. Used for call setup, authentication, ciphering location update and SMS. SACCH (Slow Associated Control Channel) Downlink and Uplink. Used to transfer signal while MS have ongoing conversation on traffic or while SDCCH is being used. On the forward link, the SACCH … Read more
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 control channel. Each TDMA multiframe with 51 frames has 4 SDCCH; SACCH/4: Slow SDCCH/4 associated control channel; Compared with the main BCCH channel, 4 signaling … Read more
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 cell; while combination 5 must be allocated to timeslots 2, 4 and 6 of the BCCH carrier. The FACCH works in the frame stealing mode, … Read more
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 request, paging response, location update request and short message request etc.) and a 5bit random reference number for MS to differentiate the access granted messages. … Read more
The development of the simulator that will be implemented can be classified in two phases. The first phase is the development of a simulator, capable for the investigation of the typical handover procedure. The second phase will include the implementation of the LAH algorithm that will consider the location of the user. Simulations that will … Read more
Handover is the mechanism that transfers an ongoing call from one cell to another as a user moves through the coverage area of a cellular system. The number of cell boundary crossings increases because smaller cells are deployed in order to meet the demands for increased capacity. If we minimize the expected number of handovers … Read more
DTX has some effect on the RXQual distribution. Normally the BER is averaged over the duration of one SACCH frame lasting 0.48 seconds and consisting of 104 TDMA frames. However, four of these TDMA frames are used for measurements, so that only 100 bursts are actually transmitted and received. When DTX is in use and … Read more