Chip shaping and channel coding for CDMA

This work considers asynchronous DS-CDMA systems with single-user receivers. The focus is on chip pulse shaping and combined error control/PN sequence spreading. It is shown that pulse shaping can significantly reduce the effects of cross-talk interference. A criterion which measures the ability of a chip waveform to reduce cross-talk interference is derived, taking into account the signal bandwidth. This work also shows that the best performance is achieved when all the bandwidth expansion is accomplished by error control coding, instead of PN sequences. Comparisons of CDMA systems using different pulse shapes are presented, taking into account the bandwidth of each pulse. Finally CDMA is compared to orthogonal multiple access (TDMA/FDMA) in an interference free environment. It is shown that, for the same bandwidth (99% energy containment bandwidth), CDMA with suitable chip waveforms and coding yields the same performance as binary orthogonal multiple access with raised cosine shaping of 70% excess bandwidth.

[1]  Andrew J. Viterbi,et al.  Very Low Rate Convolutional Codes for Maximum Theoretical Performance of Spread-Spectrum Multiple-Access Channels , 1990, IEEE J. Sel. Areas Commun..

[2]  M. Pursley,et al.  Performance Evaluation for Phase-Coded Spread-Spectrum Multiple-Access Communication - Part I: System Analysis , 1977, IEEE Transactions on Communications.

[3]  Andrew J. Viterbi,et al.  On the capacity of a cellular CDMA system , 1991 .

[4]  James S. Lehnert,et al.  Bit-to-bit error dependence in slotted DS/SSMA packet systems with random signature sequences , 1989, IEEE Trans. Commun..

[5]  Jack M. Holtzman,et al.  A simple, accurate method to calculate spread-spectrum multiple-access error probabilities , 1992, IEEE Trans. Commun..

[6]  Dilip V. Sarwate,et al.  Spread-Spectrum Multiple-Access Performance of Orthogonal Codes: Linear Receivers , 1987, IEEE Trans. Commun..

[7]  E. C. Posner.  Combinatorial structures in planetary reconnaissance. , 1968 .

[8]  G. Bottomley.  Signature sequence selection in a CDMA system with orthogonal coding , 1993 .

[9]  Anthony M. Kerdock,et al.  A Class of Low-Rate Nonlinear Binary Codes , 1972, Inf. Control..

[10]  E. A. Geraniotis,et al.  Error Probability for Direct-Sequence Spread-Spectrum Multiple-Access Communications - Part II: Approximations , 1982, IEEE Transactions on Communications.

[11]  Dariush Divsalar,et al.  Introduction to Trellis-Coded Modulation With Applications , 1991 .

[12]  Sergio Verdú,et al.  Minimum probability of error for asynchronous Gaussian multiple-access channels , 1986, IEEE Trans. Inf. Theory.

[13]  F. Amoroso,et al.  The bandwidth of digital data signal , 1980, IEEE Communications Magazine.

[14]  G. Ungerboeck,et al.  Trellis-coded modulation with redundant signal sets Part I: Introduction , 1987, IEEE Communications Magazine.

[15]  J. Bibb Cain,et al.  Error-Correction Coding for Digital Communications , 1981 .

[16]  Joseph Y. N. Hui,et al.  Throughput analysis for code division multiple accessing of the spread spectrum channel , 1984, IEEE Transactions on Vehicular Technology.