The importance of the multipoint-to-multipoint indoor radio channel in ad hoc networks

In the study of the multipoint-to-multipoint (M2M) radio channel, the physical backbone of wireless ad hoc networks, has direct application in the simulation and design of multi-hop routing protocols. The ad hoc network radio channel differs from the point-to-point or point-to-multipoint channels previously investigated, since each device may communicate with any other device. First, this paper presents a M2M measurement campaign conducted in an open-plan office area at 925 MHz. The measurements are analyzed to demonstrate spatial correlation between neighboring hops in the network. Then, the measurements are used to numerically characterize the effectiveness of a minimum-energy routing scheme. These measurements show that using existing models in the simulation of ad hoc networks can result in inaccurate results. Observations are made about the performance of a minimum-energy routing protocol in a real M2M radio channel. Finally, a channel model is suggested to more accurately represent the M2M radio channel.