Open AccessSER Analysis of QAM with Space Diversity in Rayleigh Fading Channels
Author(s) -
Kim ChangJoo,
Kim YoungSu,
Jeong GooYoung,
Mun JaeKyung,
Lee HyuckJae
Publication year - 1996
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.96.0196.0043
Subject(s) - quadrature amplitude modulation , qam , additive white gaussian noise , mathematics , rayleigh fading , maximal ratio combining , antenna diversity , diversity gain , fading , statistics , algorithm , telecommunications , bit error rate , white noise , computer science , wireless , decoding methods
This paper derives the symbol error probability for quadrature amplitude modulation(QAM) with L ‐fold space diversity in Rayleigh fading channels. Two combining techniques, maximal ratio combining(MRC) and selection combining(SC), are considered. The formula for MRC space diversity is obtained by averaging the symbol error probability of M ‐ary QAM in an additive white Gaussian noise(AWGN) channel over a chi‐square distribution with 2 L degrees of freedom. The obtained formula overcomes the limitations of the earlier work, which has been limited only to deriving the symbol error rate(SER) of QAM with two branch MRC space diversity. The formula for SC space diversity is obtained by averaging the symbol error probability of M ‐ary QAM in an AWGN channel over the distribution of the maximum signal‐to‐noise ratio among all of the diversity channels for SC space diversity. No analysis for QAM with SC space diversity has been reported yet. Analytical results show that the probability of error decreases with the order of diversity. We can also see that the incremental diversity gain per additional branch decreases as the number of branches becomes larger. On the other hand, the performance of 16 QAM with MRC becomes much better than that of SC as the number of branches becomes larger. By giving the order of diversity, L , and the number of signal points, M , we have been able to obtain the SER performance of QAM with general space diversity. These results can be used to determine the order of diversity to achieve the desired SER in land mobile communication system employing QAM modulation.