Joint discovery in wireless networks

Given a wireless network with N nodes located uniformly at random on a finite plane, we consider the problem of distributed peer discovery: all nodes want to discover as many other nodes as possible. We assume that there are a total of K physical resources dedicated for the discovery purpose. Each node can pick one resource to transmit its node identifier on, and can receive on the remaining K -1 resources. We assume that node identifiers are broadcast via coded transmission on one single physical resource using a single hop. This paper addresses link level strategies to maximize the average number of discovered devices when K <;<; N. A classical strategy of decoding one node per resource would lead to a maximum of K -1 nodes being discovered. We observe that typically this number is much lower (~K/2). We focus on n-user joint coding schemes to improve this performance and, more particularly, on joint iterative decoding (JID). It is shown through system simulations that JID may gain by significantly more than 100% over the classical single-user decoding, and by 20-25% over interference cancellation, provided that the number n of jointly decoded identifiers matches the actual interference density.