Downlink capacity enhancement in GSM systems with frequency hopping and multiple beam smart antennas

The system capacity of TDMA systems can be enhanced by utilizing the slow frequency hopping feature. More capacity gain can be achieved if interference reduction techniques such as smart antennas and discontinuous transmission are used. This paper addresses the capacity gain in the downlink due to the use of smart antennas in an FH-TDMA cellular system. We estimate the system capacity analytically and by simulation. Multiple switched beam smart antennas are utilized in the study. Perfect power control and discontinuous transmission (using voice activity) are assumed in the simulation and in theoretical analysis. The TDMA system is assumed to be GSM-like. However the analysis is valid for any TDMA system.