Experimental results of a multi-mode adaptive modulation/TDMA/TDD system for high quality and high bit rate wireless multimedia communication systems

This paper reports laboratory experimental results of a time division multiple access/time division duplex-based multi-mode adaptive modulation system (multi-mode AMS/TDMA/TDD) to support high quality and high bit rate wireless multimedia communication services under frequency selective fading conditions. The developed system includes fixed-rate quaternary phase shift keying (QPSK), 16-ary quadrature amplitude modulation (16QAM) and 64QAM to support constant bit rate media using a slowAMS, as well as two types of the fast AMS, i.e., a symbol-rate and modulation level controlled AMS (SM-AMS) and an AMS with a punctured convolutional code (AMS-PC), to support high quality and high bit rate data communication. The results confirm that the AMS-PC can achieve 1 Mbit/s transmission with its BER<10^-5 under frequency selective fading conditions with its delay spread of less than 250 ns and f_d of less than 5 Hz. The results also suggest that it is effective to adaptively select QPSK and AMS-PC according not only by the supported media but also by the terminal mobility