On the Effectiveness of Opportunistic Routing over Wireless Mesh Networks
Recently, opportunistic routing has gained much popularity for the ability to exploit the broadcast nature of the wireless medium with several practical protocols been proposed over wireless mesh networks (WMNs). These protocols usually add many mechanisms to introduce a dramatic increase in the overall network throughput, such as reliability promise and rate control. However, the evaluation of these protocols did not show how much performance benefit can be expected from each mechanism. In this paper, we provide a systematic performance evaluation on the effectiveness of reliability promise and rate control mechanisms that commonly used in opportunistic routing protocols. Our study shows that: (i) batch acknowledgment used in opportunistic routing significant improves the transmission performance over traditional routing, the true gain from opportunistic routing is not as much as claimed in previous works. (ii) rate control is important to the opportunistic routing. It ensures opportunistic routing to utilize its advantage sufficiently, but also prevents the performance degradation when the network is congested. These results give us new understanding in the effectiveness of the opportunistic routing. We then analyze and uncover reasons for these results and propose some specific schemes.