Distributed power allocation strategy in shallow water acoustic interference channels

Abstract

Due to the absence of spectrum regulation and limited bandwidth, underwater acoustic (UA) systems are prone to interfere with each other. In this paper, a decentralized power allocation strategy is proposed for multiple OFDM UA links sharing the same physical resource. These links are supposed to be noncooperative and aim at selfishly maximize their own information rate. Each link is assumed to only know the statistics of its channel and the overall noise plus interference power spectral density. A game-theoretic formulation, which explicitly takes into account the random time-varying nature of the underwater acoustic channel as well as the low speed of sound, is derived. Numerical simulations show the strong benefit of proposed approach in highly interfering channels.

Robust Noncooperative Spectrum Sharing Game in Underwater Acoustic Interference Channels

“…In this paper, a formulation of the competitive spectrum sharing problem for UA communication systems as a noncooperative game is proposed, and extends recent works on the topic [1], [2]. Every transmitter/receiver pair is a player who wants to find the power allocation that maximizes a performance metric related to its information rate, under average power constraint.…”

“…Each player i only has a statistical knowledge of its own channel h ii (n), which is assumed statistically stationary during a block of L symbols. 1 For any player i, nothing is known about h ji (n) or its realizations if j = i. Doppler effects are assumed to be compensated and it is not assumed that users are synchronized. 2 In situations where several communication systems are in the same geographical area and try to access simultaneously to the same physical resource, it may be that some or none of them are actually reliable, due to a strong interference level.…”

Power-efficient spectrum sharing for noncooperative underwater acoustic communication systems

“…Based on [5], we consider M UA communication links using OFDM modulation and transmitting at the same time on the same frequency band B divided in N subcarriers. The OFDM symbol duration and subcarrier spacing are denoted by T and ∆f respectively.…”

“…The conditions of Theorems (1) and (2) can be hard to check and may be unsatisfied in many scenarios of practical interest where one can expect that good operating points can be reached by iterative waterfilling (see for instance [5], [6]). Indeed, as these two theorems give sufficient conditions on solutions boundedness and algorithms convergence, it does not imply that their non-satisfaction will lead necessarily to divergence and unbounded power budget.…”

“…The systems considered here are assumed to be fully noncooperative, which suppose the absence of signaling between the different communication links and the inability to agree on a resource sharing policy. In recent works [5], [6], we proposed a decentralized, adaptive power allocation strategy based on game theory for noncooperative UA OFDM communication systems, where each transmitter seeks to maximize selfishly a criterion related to its information rate under average power constraint. It was shown that efficient power allocations over the available frequency band are attained by an iterative waterfilling solution.…”