1 Introduction
A wireless multihop network (WMN) [1] adopts wireless communication technologies to maintain connectivity and exchange messages between decentralized nodes in the multihop manners. This type of wireless networks are capable to perform self-creating, administering, and organizing the network connectivity. With the decentralized characteristics of the WMNs, feasible design of medium access control (MAC) protocol is considered important for performance enhancement. However, the connectivity between the network nodes is in general not guaranteed in the WMN, which incurs notorious exposed node and hidden node problems [2]. Some early attempts for resolving these problems in the literature [3], [4], [5], [6] suggested the usage of request-to-send (RTS) and clear-to-send (CTS) mechanisms, which were later adopted by the IEEE 802.11 standards. The well-adopted IEEE 802.11 MAC protocol suite [7], [8], [9], [10] can be employed in the WMNs since it has been specified to support decentralized operations called the ad hoc mode.