摘要 : Low-rate orthogonal convolutional codes (LROCC), originallyproposed by A.J. Viterbi (1971), can be used in a direct-sequencecode-division multiple access (DS-CDMA) system to achieve both spreadingof the data and providing coding g... 展开 Low-rate orthogonal convolutional codes (LROCC), originallyproposed by A.J. Viterbi (1971), can be used in a direct-sequencecode-division multiple access (DS-CDMA) system to achieve both spreadingof the data and providing coding gain. The implementation of this typeof multiplexing in a practical DS-CDMA system is presented, and thetheoretical performance of the proposed system under“other-user” noise, additive white Gaussian noise (AWGN),intercell interference, and thermal noise is established using acomputer simulation. The improvement in system performance, gainedthrough the use of a nonspreading randomizing sequence on the encodedoutput symbols, is also studied. Performance curves for a rate 1/64orthogonal convolutional code are shown, and the impact of code rate,quantization methods, and constraint length on the overall systemperformance are discussed 收起