24/04/2013 4x3 Frequency Reuse GSM Telecom Traffictelecomtraffic.com/topic167-gsm-4x3-frequency-reuse.html 1/1The basic frequency reuse mode of GSM is 4*3 frequency reuse. It is the basic of other frequency reuse modes, wealso 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 different frequencies.The above figure shows a cell cluster of 4*3 frequency reuse mode, while those inside the bold black line is a basiccell cluster model, including 4 BTS which have 3 frequency reuse group, there are 12 cells totally.In a specific allocation, all frequencies are allocated to each cell according to certain principle and same as other cellclusters. In this way, each frequency carrier is reused in different cell cluster time and time again.Certainly, other reuse model n*m means that each basic reuse cell cluster contains n BTS, and each BTS includesm frequency reuse group. All frequency carriers in this cell cluster are allocated to respective cells according tocertain principle, and by analogy for other surrounding cells.Suppose that available bandwidth is 12.2MHz, channel number from 34 to 95, the above table illustrates thefrequency carrier distribution of 4*3 frequency reuse of 12 cells in a basic cell cluster.From which cell to start the allocation of beginning frequencycarrier 34 is not restricted. As seen from the table, 5 frequencycarriers can be allocated to most cells, some cells even have 6frequency carriers. Therefore, average largest site mode isS5/5/5 under 12.2MHz condition. Under the above regularallocation mode, its impossible to have co-channel or adjacentchannel in the same cell or adjacent cells.