Effect of relaying on capacity improvement in wireless local area networks

Wireless relay nodes can improve the capacity of wireless networks. In this work, we integrate wireless relay nodes into the infrastructure of a wireless local area network (WLAN). In particular, we investigate the effect of different relay strategies and optimal utilization of a fixed number of immobile relay nodes, which maximizes the expected throughput capacity of the network. We study how the number of relay nodes, the range of users, transmission power, path loss exponent, and traffic characteristics affect the optimal relay node placement and expected throughput capacity of the network. Our results show that a time-division relay strategy can far outperform a receive-and-retransmit relay strategy. Furthermore, for a wide range of system parameters, optimally placed relay nodes can significantly increase the network expected throughput capacity.

I. Introduction

In the near future, wireless access to the Internet is expected to become a necessity. Wireless Local Area Network (WLAN) standards such as IEEE 802.11 and HiperLAN/2 provide wireless broadband data access for mobile Internet users. Because of WLAN's low cost and high bandwidth, products that support these standards and public hot spots have become increasingly popular, with many analysts envisioning a doubling in sales every year for the next five years.