Compare the spectral efficiency of the TDMA and GSM PCS and analog AMPS in terms of kHz used per voice channel. Proceed as follows:
(a) Take a simplistic approach to get a rough estimate. Find the width of each RF channel and the number of voice channels per RF channel. Ignore control channels. Calculate spectrum use in kHz per channel.
(b) Refine your estimate by considering the proportion of the overall bandwidth used by control channels in each system and therefore unavailable for voice. Assume a 12-cell repeating pattern with one control channel for each cell in TDMA and GSM. Also assume the use of one of the larger PCS frequency blocks. Check Chapter 10 to refresh your memory about AMPS control channels.
(c) Compare CDMA with the others. First find the bandwidth per voice channel for one cell, then take into account the gain in capacity that results from the ability to use all channels in all cells to arrive at an equivalent bandwidth per voice channel.