发明名称 |
Method and apparatus for demodulating trellis coded direct sequence spread spectrum communication signals |
摘要 |
A method and an apparatus for demodulating trellis coded direct sequence spread spectrum communication signals are provided. A transmitted QPSK signal is received. Binary phase-shift keyed (BPSK) despreading is performed on the QPSK signal. The BPSK despreading includes correlating the in-phase and the quadrature components of the received QPSK signal with independent PN sequences for the each of the in-phase and the quadrature components. The despread signal is then demultiplexed, and the pilot signal and the BPSK data signal are recovered. The recovered pilot signal is used to provide a channel phase estimate and a channel magnitude estimate. The recovered BPSK data signal is demodulated, despread, and decoded. The despreading and decoding includes determining a number of cross-correlation terms of the received signal using a number of transmitted biorthogonal Walsh sequences. The cross-correlation terms are used as the branch metrics in a maximum likelihood decoding algorithm. The branch metrics may be computed with a Fast Walsh Transform scaled in response to the channel phase estimate from the recovered pilot signal. The maximum likelihood decoding algorithm may be a Viterbi algorithm in which the optimum path is the path with the maximum accumulated branch metric. The decoding algorithm recovers and outputs a transmitted data bit sequence.
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申请公布号 |
US6125136(A) |
申请公布日期 |
2000.09.26 |
申请号 |
US19970001507 |
申请日期 |
1997.12.31 |
申请人 |
SONY CORPORATION;SONY ELECTRONICS, INC. |
发明人 |
JONES, WILLIAM W.;KENNEY, THOMAS J. |
分类号 |
H04B1/707;H04L1/00;H04L27/22;(IPC1-7):H04K1/00 |
主分类号 |
H04B1/707 |
代理机构 |
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地址 |
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