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
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 by searching for the frequency correction Burst transmitted via FCCH; then it finds the SCH (synchronization channel) according to the relationship between SCH and FCCH … 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
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 channel based on the type of message transmitted . In this way, the physical channels are mapped as different logical channels. In the GSM system, … Read more
Power control – already being applied in 2nd and 3rd generation networks – has high potential for improvement of the performance of mobile networks. Main benefits are: 1. It can bring down the interference in up- and downlink and hence enhances the capacity of the networks. 2. Additionally it helps to keep down the uplink-power … Read more
RE – groups & CFI – Control Format Indication in LTE is as below. RE – groups In order to support DL control information mapping, RE-groups are defined. Four useful symbols are bundled, useful in the sense that RE’s carrying the cellspecific reference symbols are not available. The one cell-specific RS case is mapped in … Read more
IP Networks use Routers to do the switching based on IP addresses, Layer 3 routing protocols like BGP or OSPF an Ethernet networks use 48 bit MAC addresses Spanning Tree is used to route because users, base stations, routers, etc will all need IP addresses (It is an IP-based system) There are Public (Internet routable) … Read more
The action of camping on provides access to services. The network provides different levels of service to a UE in either Idle mode or Connected mode. Three levels of services are defined: LIMITED SERVICE: emergency calls on an acceptable cell. Acceptable cell: UE may camp to obtain limited service like emergency call. The minimum set … Read more
Random access procedure is performed for the following five events: • Initial access from RRC_IDLE; • RRC Connection Re-establishment procedure; • Handover; • DL data arrival during RRC_CONNECTED requiring random access procedure; • UL data arrival during RRC_CONNECTED requiring random access procedure; E.g. when UL synchronization status is “non-synchronized” or there are no PUCCH resources for … Read more