A TDMA-CDMA cellular system

This paper proposes a new cellular system which combines code division multiple access (CDMA) and time division multiple access (TDMA) to improve the performance of the cellular system. A synchronized TDMA-FDMA system is used within cells and an asynchronous CDMA system is used across the cells. The cell signals are spread by unique spreading codes to reduce inter-cell interference. Simulations show that the bit error rate (BER) delivered by the proposed system for a E_b/N ₀ greater than a certain value is better than that for conventional cellular TDMA system. This improvement is the direct result of spreading signals used to decrease the inter-cell co-channel interference (CCI). The improvement thus realized can be translated into reduction of cluster size and thus towards capacity improvement