Symbol Rate Controlled Adaptive Modulation/TDMA/TDD for Wireless Personal Communication Systems

Toyoki UE  Seiichi SAMPEI  Norihiko MORINAGA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E78-B   No.8   pp.1117-1124
Publication Date: 1995/08/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Technologies for High-Speed Mobile Communications)
Category: 
Keyword: 
adaptive modulation,  QAM,  TDMA/TDD,  wireless personal communication,  multipath fading,  

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Summary: 
This paper proposes a symbol rate controlled adaptive modulation/TDMA/TDD for future wireless personal communication systems. The proposed system controls the symbol rate according to the channel conditions to achieve wide dynamic range of the modulation parameter control as well as to improve the delay spread immunity. The main purpose of the proposed system is to increase the data throughput with keeping a certain transmission quality, especially in frequency selective fading environments. For this purpose, the proposed system predicts the C/N0 (carrier power-to-noise spectral density ratio) and the delay spread separately, and selects the optimum symbol rate that gives the maximum bit rate within a given bandwidth satisfying the required BER. The simulated results show that the proposed system can achieve higher transmission quality in comparison with the fixed symbol rate transmission system in both flat Rayleigh and frequency selective fading environments. The results also show that the proposed system is very effective to achieve higher bit rate transmission in frequency selective fading environments.