Relay-Assisted ARQ in Wireless Ad-Hoc Networks

In this paper we study a simple protocol utilizing two-hop cooperative diversity augmented with "automatic repeat request" (ARQ) for multi-hop ad-hoc networks. This protocol, which we call relay-assisted ARQ (RARQ), requires minimal a priori knowledge of node positions and channel fading states. Although many variations of ARQ have been proposed and analyzed in the literature, applying both ARQ and cooperative diversity in a random environment raises issues and possibilities that have not been thoroughly investigated before. In contrast to most published work on cooperative diversity relaying, where the node positions or average channel characteristics are given as parameters, we study analytically and through simulations the expected system-wide benefit of RARQ in ad-hoc wireless networks, where the node locations follow a homogeneous Poisson point process and the channel fading states are random.