Turbo-Codes and Turbo-Coded Modulation in CDMA Mobile Radio Systems for Short Frame Transmission

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Abstract:

For the last four years, binary parallel concatenated recursive convolutional codes termed Turbo-Codes received great attention due to their amazing error correcting capabilities. Nevertheless, reaching near Shannon limit performance is only possible with a very large interleaver size preventing an application for speech-transmission. This paper presents simulation results for a short-frame data transmission system based on DS-CDMA (Direct-Sequence Code Division Multiple Access) employing Turbo-Codes. As a result, it is shown that Turbo-Codes are no longer superior to classical convolutional codes if the same decoding costs are assumed. Furthermore, simulation results illustrate that coded modulation schemes are not well suited for the application in CDMA systems. Finally, it is proved that an accurate channel estimation is necessary to take advantage of high coding gains.

Document type:

Conference Paper

Publication:

Sun City, South Africa, 2. - 4. September 1998

Conference:

IEEE International Symposium on Spread Spectrum Techniques & Applications (ISSSTA 98)

Pages:

364-368

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