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
S-CRITERION The cell selection criterion S is a pre-condition for suitable cells. The conditions for E-UTRAN, UTRAN FDD and GSM cells are listed in the figure. R – CRITERION – CELL RESELECTION The cell reselection evaluation process depends on whether Hierarchical Cell Structure (HCS) is used or not. In order to perform cell reselection UE … Read more
Logical channels are in a one-to-one fashion associated with radio bearers. Logical channel types are used to distinguish the type of information transmitted within the attached radio bearer. The two major groups of logical channel types are therefore control channels for signaling and traffic channels for IP user data. Currently the following logical channel types … Read more
Transport channels are used as the basic transmission service offered by layer 1 to MAC. MAC will use transport channels to multiplex and demultiplex logical channels onto and from them. In contrast to logical channel types, referring to the type of information transmitted, transport channel types are used to indicate the transport characteristics. This means … Read more
The actual frequency planning of certain areas is usually conducted with such areas divided into segments geographically, i.e., first divide a complex network into small networks. However, there should be some frequency carriers (when the frequency is enough) reserved at the boundary of the segments or the frequency carriers should be divided. Such boundary should … Read more
Isolated reuse technology refers to 1*3 or 1*1 reuse with short reuse distance and severe interferences, radio frequency hopping technology has to be adopted. The aggregate of hopping frequencies needs to be far more larger than the number of TRX (more than twice), MA, HSN and MAIO parameter are used to avoid frequency conflict. Let’s … Read more