Opportunistic Data Transfer in Wireless Multi-hop Networks : An Overview
Zehua Wang, Yuanzhu Peter Chen, Cheng Li · 2010
A multi-hop wireless network is a wireless communication network, where some nodes are not within a direct transmission range of each other and rely on other nodes to forward data. It was originally put forward for battlefield communication and disaster relief. In the past, although a number of multi-hop data transmit protocols and many innovative forwarding algorithms have been explored, the working routines of these protocols and algorithms follow those used in the Internet model, where they might work effectively only in wired networks. It is obvious that solutions adopted from Internet may not work properly in multi-hop wireless networks because the broadcast nature of wireless communication is not considered. In traditional protocols for multi-hop wireless networks, a unicast transmission can be picked up by multiple nodes, but only one of them is the intended receiver (destination node or relay). If this node has failed to receive the transmission, the packet has to be resent again. In effect, all nodes that have received the transmission that are closer to the destination than the transmitter could be relays, so it is not necessary to rely on a articular node to forward the data in principle. This method can save a great deal of resources compared to traditional methods. Recently, the importance of utilizing the broadcast nature of multi-hop wireless networks is being recognized and considered in network protocol design, known as opportunistic data forwarding. This paper reviews opportunistic data forwarding approaches in multi-hop wireless networks. It explains the main differences between opportunistic and traditional methods, and surveys recent work in this area. The challenges and open questions for future research will also be discussed in this paper.