Symbol Error Probability of Time Spread PPM Signals in the Presence of Co-channel Interference

Jinsong DUAN  Ikuo OKA  Chikato FUJIWARA  

IEICE TRANSACTIONS on Communications   Vol.E81-B   No.1   pp.66-72
Publication Date: 1998/01/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Communication Theory
time spread PPM,  CDMA,  moments,  maximum entropy method,  symbol error probability,  

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Time spread (TS) pulse position modulation (PPM) signals have been proposed for CDMA applications, where the envelope detection is employed instead of coherent detection for easier synchronization of PPM. In this paper, a new method of deriving symbol error probability (SEP) of TS PPM signals in the presence of interference is introduced. The analysis is based on the moment technique. The maximum entropy criterion for estimating an unknown probability density function (PDF) from its moments is applied to the evaluation of PDF of envelope detector output. Numerical results of SEP are shown for 4, 8 and 16PPM in the practical range of signal-to-noise power ratio (SNR) and signal-to-interference power ratio (SIR) of 5, 10 and 20 dB. SEP by the union bound is also given for comparison. From the results it is noted that when PPM multilevel number is small, the union bound goes near to SEP by the proposed method, but when it increases the difference of the SEP by the bound and proposed method becomes larger. The effect of central frequency offset of TS-filter is evaluated as an illustrative example.