Fractional Frequency Reuse for Intercell Interference Mitigation in Two-Tier Underwater Multicell OFDM Wireless Networks

Abstract

Recently, acoustic communications over underwater multicell OFDM wireless networks have received significant research attention. Due to the severe underwater fading conditions, available bandwidth over underwater wireless networks are much more scarce than terrestrial wireless networks. Thus, various frequency reuse techniques are highly demanded for underwater wireless networks. However, the frequency reuse imposes the new and complicated designing tradeoff among co-channel interference on cell-edge users, the overall network throughput, and spectrum efficiency, which has significant impact on the performance for underwater multicell OFDM wireless networks. To overcome these new challenges, in this paper we propose a novel fractional frequency reuse (FFR) scheme for intercell interference mitigation under the two-tier (interior zone and edge zone) based underwater multicell OFDM wireless networks. Our main objective is to guarantee the edge-user's QoS requirements in terms of SINR and outage probability and to optimize the spectrum efficiency of the entire underwater multicell wireless networks. We also derive the closed-form expressions of outage probability and spectrum efficiency. The extensive simulations validate and evaluate our proposed schemes, showing that our schemes outperform the other existing frequency reuse schemes for underwater wireless networks in terms of signal-to-interference-plus-noise, outage probabilities of cell-edge users, and spectrum efficiency.