GSM Underlaid Overlaid Frequency Allocation and Configuration Underlaid Overlaid Frequency Allocation In the Overlaid/Underlaid technology, all frequency carriers in the cell are divided into two parts, of which the TRX power of some frequency carriers is lowered, then two Overlaid/Underlaid with different coverage appear, as shown in the below figure. The frequency carriers used by … Read more
Capacity increase when reuse density is multiplied: Supposing there are 300 cells Bandwidth: 8 MHz (40 frequency) Normal 4*3 reuse: reuse density=12 Network capacity = 40/12 * 300 = 1000 TRX Multiple reuse: “0” BCCH layer: re-use =14, (14 frq.) “+” Normal TCH layer: re-use =10, (20 frq.) ” ^-“ Aggressive TCH layer: re-use = … Read more
Multi-layer reuse pattern technology means to divide the whole frequency resources into different subgroups according to specific principles. Each subgroup allocates frequency carriers to every cell by means of different reuse models, so the reuse density of each frequency carrier as well as the interference will be different in each cell. The frequency carrier with … Read more
The basic frequency reuse mode of GSM is 4*3 frequency reuse. It is the basic of other frequency reuse modes, we also call it regular frequency reuse model. “4” represents 4 sites, “3” represents 3 cells in each site. Totally 12 cells become a basic frequency reuse cluster. Different cells in the same cluster have … Read more
Requirement for Interference and Carrier to Interference Ratio in GSM GSM is an interference restricted system. Carrier-to-interference ratio (C/I), also called interference protection ratio, refers to the ratio of all useful signals to all useless signals. In GSM system, this ratio is relevant to the instantaneous location and time of MS due to irregular landform, … Read more
BCC is a part of BSIC. For its function, please refer to above sections. BCC is composed of 3 bits. The available range is from 0 to 7. BSIC includes BCC and NCC which is transmitted on SCH. BCC is a part of BSIC, used to identify different cell with the same BCCH in the … Read more
NCC is a part of BSIC. MS uses it to distinguish adjacent BTS that belong to different GSM PLMN. NCC is composed of 3 bits, with the range of 0 to 7. NCC and BCC together form the base station identity code (BSIC), transmitted on synchronous channel of each cell. In many cases, different GSM … Read more
What is BSIC and its use in GSM 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 … Read more
To uniquely identify each cell in the GSM PLMN, the network operator needs to allocate one code for each cell, which is the cell identity (CI). Cell identity, together with LAI, is used for identity of each cell in the world. CI is composed of 16 bits, The available range is 0~65535 Cell Identity (CI) … Read more
What is Use of LAC in GSM What is Use of LAC in GSM Location Area Code（LAC) : To locate the location of MS, the whole area covered by each GSM PLMN is divided into different location areas. LAC is used to identify different location areas. LAI contains LAC, which is composed of two bytes. … Read more