Assignment:
A terrestrial radio link transmits a CDMA signal from a base station using a spreading code with a chip rate of 1.0 Mchips per seconds. The message data rate of the signal is 10 kbps.
a. Why is a spreading code used in a CDMA radio system?
b. What is the coding gain of the correlator in a CDMA receiver when it is synchronized to the 1.0 Mchips/s signal?
c. A receiver of the CDMA signal has a C/(N+I) ratio of -8.0 dB at its input. What is the CNR at the output of the correlator, assuming ideal operation?
d. A second CDMA base station is located 2 km away from the first station and transmits a different spreading code. As a receiver synchronized to the first base station signal moves close to the second base station it loses synchronization with the CDMA signal from the first base station. Why?