A co-channel interference cancellation technique using orthogonal convolutional codes

This paper proposes and evaluates a new co-channel interference cancellation technique that utilizes orthogonal convolutional codes on a multipath Rayleigh fading channel. In a spread spectrum multiple access environment, co-channel interference (CCI) limits the performance of the communication link. To remove this interference, several CCI cancellation techniques have been proposed, including the technique that does not require the receiver to have knowledge of the cross-correlation between user sequences. This method leaves residual interference after the cancellation caused by errors in the initial decisions. To reduce the residual interference and improve the initial decisions, the proposed scheme utilizes the error-correcting capability of orthogonal convolutional codes. This paper evaluates the performance of this scheme. Our results show that the proposed CCI canceller offers an improvement in capacity by a factor of 1.5 3 as compared with a conventional canceller on a multipath Rayleigh fading channel. The proposed canceller works in the presence of residual interference due to imperfect cancellation. The proposed canceller also has a capacity improvement with the use of soft handoff in a multicell configuration.