Rate-compatible convolutional codes for multirate DS-CDMA systems

| New nested convolutional codes and rate-compatible punctured convolutional (RCPC) codes with high constraint lengths and wide range of code rates are presented. It is shown that these codes are almost as good as the existing optimum convolutional codes for the same rates. The eeects of varying the design parameters of the RCPC codes, i.e. the mother code rate, the puncturing period and the constraint length are evaluated. Codes originating from rate 1=4 mother codes with constraint lengths 7 to 10 are presented. Also, rate matching in a multicode direct-sequence code-division multiple-access (DS-CDMA) system is examined, and results are evaluated in terms of the eeciency for speciic bit error probabilities. Keywords|rate-compatible punctured convolutional codes (RCPC codes), nested convolutional codes, optimum distance spectrum, multichannel systems, rate matching, mul-ticode direct-sequence code-division multiple-access (DS-CDMA).