Wireless Ad Hoc and Sensor Networks

382 Wireless Ad Hoc and Sensor Networkscompared to the OLSR and AODV protocols, according to Figure 8.15,due to the energy-delay optimization methods of the proposed OEDRprotocol. On the whole, the NS-2 simulation results suggest that the proposedOEDR protocol finds the minimum delay path from source todestination and optimizes the energy-delay product. OEDR protocol canalso be applied to a wireless sensor network. Next, we show an extensionof OEDR, known as optimal energy-delay subnet routing protocol(OEDSR), applied to a WSN.8.6 Routing in Wireless Sensor NetworksRecent advances in WSNs have made it possible for small, inexpensive,low-power sensor nodes to be distributed across a geographical location.The information can then be gathered and sent to the end user or BS throughwireless communication, as shown in Figure 8.17. These tiny sensor nodeshave sufficient intelligence for signal processing and data broadcasting, butcompared to other wireless networks, WSNs have resource constraints suchas limited battery power, bandwidth, and memory.Additionally, because of fading wireless channels, WSNs are prone tofailures or intermittent connectivity. Consequently, WSNs have to periodicallyself-organize and generate routes from the nodes to the BS. Thesensor nodes broadcast information to communicate with each other inthe network, whereas ad hoc networks use peer-to-peer communication.The performance metrics usually considered when working with a WSNare power consumption, connectivity, scalability, and limited resources.WirelesscommunicationBasestationWired orwirelesscommunicationEnd usersSensor nodesFIGURE 8.17Wireless sensor network.