Receiver Design for Fast Frequency-Hopping Multiple Access System

• Main Authors: Zhe-An Lin, 林哲安
• Other Authors: Li-Der Jeng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/77440031569392232215

碩士 === 中原大學 === 電子工程研究所 === 94 === In order to avoid many kinds of jamming, the technology of spread spectrum has been developed. Frequency-hopping multiple access (FH-MA) has been widely studied and known to be a clever technique for mitigating multipath fading because of its frequency diversity. The purpose of multi- users system is to share the same bandwidth and transmitting the signals at the same time. Besides the e ect of the channel noise, if another users transmit the symbol at the same band, it will result of hitting and interference each other. This phenomenon is called multiple access interference (MAI). In this paper, fast frequency hopping/M-ary frequency shift keying multiple access (FFH/MFSK-MA) diversity receivers are investigated under additive white Gaussian noise (AWGN) and Rayleigh fading channels. Noncoherently envelope detector and energy detector are employed for MFSK demodulation. Since maximum-likelihood (ML) diversity combing rule is di cult to derive in MA environment, we consider 4 suboptimal diversity combing receivers. To integrate demolulator and diversity combiner, we study di erent re- ceiver structures. The performance of several diversity combining receivers is compared by computer simulations.