Modulation level controlled adaptive modulation systems with base-station-based transmission/reception diversity scheme for personal communications

This paper proposes a modulation level controlled adaptive modulation system with the base-station based transmission/reception diversity scheme to achieve high bit rate and high quality transmission for personal communication systems. In the proposed system, the diversity branches combining techniques take account of not only the received signal level but also the delay spread to improve the performance. So, the performance will be improved in both flat Rayleigh and frequency selective fading environments. The performance of the proposed system is evaluated by computer simulation. The results show the the proposed systems can achieve 250 kbit/s and 3.9 bit/symbol satisfying BER=10^-3 even at the normalized spread of τ _rmsT_s=0.17 (T_s is a symbol duration)