| 摘要 |
<p>In a spread spectrum communication system a transmitter uses a spreading codeword to obtain spreaded digital symbols from source symbols. These spreaded digital symbols are transmitted to a receiver which uses de-spreading means to obtain the originally transmitted source symbols. A problem in spread spectrum transmission system is that due to multipath transmission so-called intersymbol interference can occur. This intersymbol interference causes an increased bit error rate. In the transmission system according to the present invention it is proposed to use a de-spreading codeword which is shorter than the spreading codeword, so no overlap of signals originated from different symbols with the despreading codeword occurs. Preferably, the spreading codeword comprises a concatenation of the despreading codeword and a preamble. This preamble can be a cyclically permutated part of the despreading codeword.</p> |
