A Novel FEC Scheme for Differentially Detected QPSK Signals in Mobile Computing Using High-Speed Wireless Access (Special Issue on Mobile Computing)
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概要
- 論文の詳細を見る
This paper proposes a novel FEC (forward error correction) scheme for high-speed wireless systems aiming at mobile computing applications. The proposed scheme combines inner nonredundant error correction with outer parallel encoding random FEC for differentially detected QPSK (quadrature phase shift keying) signals. This paper, first, examines error patterns after the differential detection with nonredundant error correction and reveals that particular double symbol errors occur with relatively high probability. To improve the outer FEC performance degradation due to the double symbol errors, the proposed scheme uses I and Q channel serial to parallel conversion in the transmission side and parallel to serial conversion in the receiving side. As a result, it enables to use simple FEC for the outer parallel encoding random FEC without interleaving. Computer simulation results show the proposed scheme employing one bit correction BCH coding obtains a required E_b/N_O improvement of 1.2dB at a Pe of 10^lt-5gt compared to that with the same memory size interleaving in an AWGN environment. Moreover, in a Rician fading environment where directional beam antennas are assumed to be used to improve the degradation due to severe multipath signals, an overall E_b/N_O improvement at Pe of 10^lt-5gt of 3.0dB is achieved compared to simple differential detection when the condition of delay spread of 5 nsec, carrier to multipath signal power ratio of 20dB and Doppler frequency at 20GHz band of 150Hz.
- 社団法人電子情報通信学会の論文
- 1997-08-25
著者
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SUGIYAMA Takatoshi
NTT Wireless Systems Laboratories
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Umehira Masahiro
NTT Wireless Systems Laboratories
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Umehira Masahiro
Ntt Wireless Communication Systems Laboratories
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