Soft frequency reuse for intercell interference mitigation in two-tier underwater multicell OFDM wireless networks

Underwater acoustic communications have received significant research attention with the increasing ocean explore applications. Due to the frequency-dependent path loss and fading characteristics of the acoustic channel, and scarce available bandwidth, it is more important to employ frequency reuse scheme to improve the spectrum efficiency and the entire network performance. 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 employ soft frequency reuse (SFR) scheme in underwater acoustic multicell networks to balance the intercell interference mitigation and the spectrum efficiencies while guaranteeing the edge-user's QoS requirements in terms of signal-to-interference-plus-noise (SINR) and outage probability. The extensive simulations validate and evaluate our proposed schemes, showing that the our schemes outperform the other existing frequency reuse schemes for underwater wireless networks in terms of SINR, outage probabilities of cell-edge users, and spectrum efficiency.

I. Introduction

At present, underwater acoustic wireless communications have been widely applied in a large number of important applications including oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, and tactical surveillance [1] – [3]. The goal of underwater acoustic wireless communications is to transmit big data with a high-data rate and quality of service (QoS) provisioning [4] – [6]. On the other hand, according to the unique underwater acoustic channel fading characteristics as compared with the radio frequency (RF) channels over terrestrial wireless networks, such as acoustic signal attenuated with both increasing distance and frequency and limited available bandwidth, it is more important to employ frequency reuse scheme to improve the spectrum efficiency and entire network performance.