Study of multidimensional coded modulation in land mobile radio communication

Abstract

A high reliability in communication is required in data transmission, such as personal computer communication and facsimile, in the digital land mobile communication. One means to cope with this problem is the coded modulation. This paper discusses the multidimensional coded modulation which is one such coded modulation method. Little consideration has been given to the application of this method to land mobile communication. In this study, 16 QAM is employed, applying the fading distortion compensation to the modulation method. The interleaving method is combined, and the bit-error rate of the multidimensional coded modulation system under the fading environment is investigated. The four-, eight-, and 16-dimensional cases are investigated by computer simulation, and a gain of approximately 3 dB is indicated for the eight- and 16-dimensional cases. The reason for such a small improvement is due to the unbalance of the error-rate performance in the coded symbol block. From such a viewpoint, the bit-error rate is analyzed by dividing the bit sequence in the symbol block into three parts, considering only the eight-dimensional case. As a result of the effort to reduce the unbalance of the bit-error rate performance under fading, the improvement of approximately 6 dB is realized for the bit-error rate of 103, thereby increasing the performance improvement.