14-1. Consider an FDMA system for multimedia data users. The modulation format requires 10 MHz of spectrum for each user, and guard bands of 1 MHz are required on each side of the allocated spectrum in order to minimize out-of-band interference. What total bandwidth is required to support 100 simultaneous users in this system?

14-2. GSM systems have 25 MHz of bandwidth allocated to their uplink and downlink, divided into 125 TDMA channels with 8 user timeslots per channel. A GSM frame consists of the 8 timeslots, preceded by a set of preamble bits and followed by a set of trail bits. Each timeslot consists of 3 start bits at the beginning, followed by a burst of 58 data bits, then 26 equalizer training bits, another burst of 58 data bits, 3 stop bits, and a guard time corresponding to 8.25 data bits. The transmission rate is 270.833 kbps.

1. Sketch the structure of a GSM frame and a timeslot within the frame.

2. Find the fraction of data bits within a timeslot as well as the information data rate for each user.

3. Find the duration of a frame and the latency between timeslots assigned to a given user in a frame, neglecting the duration of the preamble and trail bits.

4. What is the maximum delay spread in the channel such that the guard band and stop bits prevent overlap between timeslots?

14-3. Consider a DS CDMA system occupying10 MHz of spectrum. Assume an...