BER performance of M-ary/ASK-SS system using compact matched filter bank for optical ZCZ code

The optical ZCZ code, which is a set of pairs of binary and bi-phase sequences with zero correlation zone, can provide code division multiple access (CDMA) communication system without co-channel interference. And M-ary amplitude shift keying spread spectrum (M-ary/ASK-SS) system using this code can detect a desired sequence without interference of undesired sequences. We proposed the compact construction of a bank of matched filters for this code, which is called tree-type bank of matched filters. However, M-ary/ASK-SS system using this filters might go down the bit error rate (BER) performance because input-output characteristics of this filters for zero correlation zone 4n - 2 is nonlinear characteristics. In this paper, we clarify that BER performance in ASK-SS and M-ary/ASK-SS system under the additive white Gaussian noise (AWGN) and the frequency nonselective fading environments are not influenced by nonlinear characteristics of this filters by the computer simulation. The BER performance of ASK-SS system using tree-type bank of matched filters under the AWGN and frequency nonselective fading environments go down compared to BER performance of parallel-type filters as expected. But the BER performance of M-ary/ASK-SS system using this compact filters under the AWGN and frequency nonselective fading environment are almost equal compared to BER performance of parallel-type filters. In fact, the BER performance in M-ary/ASK-SS are not influenced by nonlinear characteristics of tree-type bank of matched filters.