Abstract-We present a probabilistic polling scheme for estimating the size of a group of nodes affected by the same event. We analyze the bias of the proposed scheme and show how it can be completely eliminated. Our scheme differs from previous work in several important ways. First, it is generic in the sense that it is not dependent on the physical properties of the underlying network. Second, it uses a "one-shot" estimation technique that does not depend on the results of previous rounds. Finally, the estimating nodes control the number of feedback messages, thus allowing a good balance between the overhead imposed by the scheme and its precision. We compared our scheme to previous works and saw a notable performance improvement: our scheme reduced the number of response messages by 80-90% while obtaining the same precision.

Abstract-Streaming multicast is one of the most important Transport layer services in future broadcast wireless networks. This service enables the delivery of real-time voice and video applications to an almost unlimited number of mobile devices, by taking advantage of a base station's ability to transmit a single packet to all the nodes in its cell. While strict delivery assurance is not necessary and not possible for such applications, some level of assurance is provided using Transport layer FEC (Forward Error Correction) codes. In this paper we show how to improve the performance of large-scale partially reliable multicast streaming in broadcast wireless networks, using the NATO! scheme. NATO!, presented in another paper, is a generic real-time scheme that allows a node to estimate the size of any subset of nodes affected by the same event using a few messages received from this subset.