Adaptive Modulation/TDMA Scheme for Large Capacity Personal Multi-Media Communication Systems

Seiichi SAMPEI

IEICE TRANSACTIONS on Communications   Vol.E77-B    No.9    pp.1096-1103
Publication Date: 1994/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Mobile Multimedia Communications)
adaptive modulation,  multi-level QAM,  multipath fading,  personal communication,  cellular system,  

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This paper proposes an adaptive modulation/TDMA scheme to achieve high capacity personal multi-media communication systems. TDMA is employed to cope with various bit rate for multi-media services. The modulation scheme is selected from 1/4-rate QPSK, 1/2-rate QPSK, QPSK, 16QAM and 64QAM according to the received C/IC (power ratio of the desired signal to the co-channel interference) and the delay spread. The spectral efficiency is evaluated by using the simulated bit error rate (BER) performance as well as the cumulative distribution of the C/IC with parameters of cell configurations. The results show that the spectral efficiency of the proposed scheme is 3.5 times higher than that of the conventional QPSK systems at the outage probability of 10%, and the effect is more remarkable at lower outage probability. The results also show that the proposed adaptive modulation is effective in improving delay spread immunity.