Co-Channel Interference Cancellation in OFDM Networks using Coordinated Symbol Repetition and Soft Decision MLE CCI Canceler

TL;DR

This paper proposes a novel interference cancellation scheme for OFDM networks that uses coordinated symbol repetition and soft decision maximum likelihood methods, significantly improving signal quality at cell edges.

Contribution

It introduces a new coordinated symbol transmission scheme combined with a soft decision MLE CCI canceler and modified MRC, enhancing interference mitigation in OFDM networks.

Findings

Achieves 9 dB SIR gain in multipath channels

Achieves 6 dB SIR gain in flat-fading channels

Effective under both frequency-selective and non-selective channels

Abstract

In this paper, a new scheme of downlink co-channel interference (CCI) cancellation in OFDM cellular networks is introduced for users at the cell-edge. Coordinated symbol transmission between base stations (BS) is operated where the same symbol is transmitted from different BS on different sub-carriers. At the mobile station (MS) receiver, we introduce a soft decision maximum likelihood CCI canceler and a modified maximum ratio combining (M-MRC) to obtain an estimate of the transmitted symbols. Weights used in the combining method are derived from the channels coefficients between the cooperated BS and the MS. Simulations show that the proposed scheme works well under frequency-selective channels and frequency non-selective channels. A gain of 9 dB and 6 dB in SIR is obtained under multipath fading and flat-fading channels, respectively.