The great economic success of modern mobile radio systems such as GSM and DCS means even greater utilization of the capacity of existing channels. It is therefore immensely important to exactly adhere to the GSM specifications. In GSM systems, the available frequency range is divided according to the FDMA procedure] (frequency division multiple access) into radio channels of 200 kHz each. Each radio channel is further divided into eight traffic channels through a time multiplexing TDMA procedure (time division multiple access). These channels contain the information (voice and data signals) in "bursts." In the case of a channel width of 200 kHz, this results in the typical GSM system channel number of 124 channels with bandwidths of 25 MHz (the first channel is not normally used). For DCS, there are 372 channels with a bandwidth of 75 MHz.
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