Multihop Wireless Networks: Opportunistic Routing

5.2 System Model and Opportunistic Routing Primer

We consider a multihop wireless network with N nodes. Each node ni (1 ≤ i ≤ N) is equipped with one or more wireless interface cards, referred to as radios in this work. Denote the number of radios in each node ni as ti (i = 1…N). Assume K orthogonal channels are available in the network without any interchannel interference. We consider the system with channel-switching capability, such that a radio can dynamically switch across different channels. We assume there is no performance gain to assigning the same channel to the different radios on the same node (i.e. we do not consider MIMO). For simplicity, we assume each node ni transmits at the same data rate Ri among all its radios and channels. However, our model can be easily extended to the multirate case. We also assume half-duplex on each radio-that is, a radio cannot transmit and receive packets at the same time. This is usually true in practice. There is a unified transmission range and interference range for the whole network. The transmission range and interference range are largely dependent on the transmission power, which is fixed in our model. Typically, the interference range is larger than the transmission range. Two nodes, ni and nj, can communicate with each other if the Euclidean distance between them is less than the transmission range and they are operated on the same channel. Due to the unreliability of the wireless links, a packet reception ratio (PRR) is associated ...