Buffer scalability of wireless networks

Abstract

We investigate the existence of scalable protocols that can achieve the capacity limit of c/ √N per sourcedestination pair in a large wireless network of N nodes when the buffer space of each node does not grow with the size of the network N. We show that there is no end-to-end protocol that is capable of carrying out the limiting throughput of c/ √N with nodes that have constant buffer space. In other words, this limit is achievable only with devices whose buffers grow with the size of the network. On the other hand, we establish that there exists a protocol which realizes a slightly smaller throughput of c/ √N log N when devices have constant buffer space. Furthermore, we show that the required buffer space can be very small, capable of storing just a few packets. This is particularly important for wireless sensor networks where devices have limited resources. Finally, from a mathematical perspective, this paper furthers our understanding of the difficult problem of analyzing large queueing networks with finite buffers for which, in general, no explicit solutions are available. © 2006 IEEE.