A measurement-based model for estimating transmission capacity in a wireless mesh network

Abstract

In the past decade, wireless multihop networks have caught the fancy of wireless networking researchers and practitioners alike. However, wireless being a broadcast medium, links in close neighborhood interfere causing a capacity degradation. Network modeling community has investigated this issue of interference and how it limits the capacity of wireless multihop networks [3]. Much of these works use a somewhat abstract and idealized model of interference, initially proposed in the seminal work of Gupta and Kumar [2]. These models describe how two communicating links interfere based on physical distances between the transmitters and receivers, oversimplified radio propagation model, idealized transmitter and receiver characteristics, and so on. Such models have so far been sufficient for getting a highlevel understanding of the behavior of wireless networks and even for designing protocol support, but it has remained unclear how these models could be useful in practice for an operational network. Research in Wireless Networks needs to consider the phenomenon of interference between transmissions. A model for interference is an essential input to the design of any routing protocol. Design of a fairness model, or a capacity model for a wireless network also requires an interference model. Transport protocols and channel assignment protocols also need an understanding of wireless interference. So, its imperative to have a realistic and accurate interference model to assist research in various areas in wireless networking. Our work follows on the lines of previous works done on developing a measurement based model for quantifying the interference limited link capacity [4, 5]. In this work, we estimate the impact of interference on the transmission capacity of a node. When a node transmits a packet, all the other nodes who can either receive the packet, or can detect the transmission’s signal become silent. Thus, a transmitter