Cooperative communications scheme with interference management under ICI for OFDM LTE-A systems

In long term evolution (LTE) systems, the achievable cell spectral efficiency is often limited by the inter carrier interference (ICI) or coverage shortage of base stations. Hence, in LTE-Advanced, cooperative communication has been proposed as an efficient technique to extend coverage, and improve throughput and link reliability. However, its performance gain is degraded in the presence of co-channel interference. In this paper, we propose cooperative communications scheme with interference management for LTE-A systems. The proposed scheme is based on best sub-channel selection (BSS) technique. BSS maximizes the received signal to interference plus noise ratio (SINR) for each orthogonal frequency-division multiplexing (OFDM) subcarrier while keeping the interference levels below a certain threshold. The scheme is using decoding and forward (DF) relaying protocol, and maximum ratio combined (MRC) receiver to combine the direct link (DL) and selected relaying signals. We derive exact closed form expressions of outage probability, ergodic capacity, and average bit error probability for the proposed scheme. In addition, we analysis the optimal sub-channel selection period for LTE-A system under users mobility. Simulations are used to validate the analytical expressions. The results confirm the advantage of the proposed scheme in enhancing interference management and link reliability.