SYMBOL RATE-CONTROLLED ADAPTIVE MODULATION TDWIA TDD FOR WIRELESS PERSONAL COMMUNICATION-SYSTEMS

This paper proposes a symbol rate controlled adaptive modulation/TDMA/ TDD for future wireless personal communication systems. The proposed s ystem 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 prop osed system is to increase the data throughput with keeping a certain transmission quality, especially in frequency selective fading environ ments. For this purpose, the proposed system predicts the C/N-O (carri er power-to-noise spectral density ratio) and the delay spread separat ely, and selects the optimum symbol rate that gives the maximum bit ra te 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 achie ve higher bit rate transmission in frequency selective fading environm ents.