Computational Complexity Reduction of Trellis-Coded Co-channel Interference Canceller

Hidekazu MURATA

IEICE TRANSACTIONS on Communications   Vol.E79-B    No.3    pp.342-352
Publication Date: 1996/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Advanced Adaptive Radio Communication Technologies)
Category: Modulation, Demodulation
digital cellular radio,  co-channel interference,  interference canceller,  trellis coded modulation,  

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Co-channel interference is a major factor limiting spectral efficiency of a cellular radio system. The trellis-coded co-channel interference canceller (TCC) leading to the significant increase of traffic capacity of a cellular system has been proposed. In this scheme, a maximum-likelihood sequence estimation implemented with the Viterbi algorithm is extended to estimate both desired signal and co-channel interference, and combined with trellis-coded modulation to enhance the co-channel interference cancelling capability. The complexity of TCC grows exponentially with the channel memory and the constraint length of the trellis encoder. In this paper, two reduced-state sequence estimation algorithms, namely, the delayed decision feedback sequence estimation and the M-algorithm, are applied to TCC and their performance is compared. In addition, effective trellis coded modulation schemes to reduce the computational complexity are proposed. The performance of these schemes is examined through simulations, and compared to that of a conventional interference canceller.