Cooperation in Wireless Ad Hoc and Sensor Networks

Cooperation is a key issue in Ad Hoc and sensor networks (Wireless Ad Hoc Sensor Networks, WAdSN) for several reasons. Usually ad-hoc and sensor networks are two concepts related to networks consisting of wireless nodes. Our approach in this chapter considers that these nodes have common features such as tiny size, low computational and storage resources and low autonomy (understood as battery lifetime). Frequently, these nodes can acquire information from the environment via different sensors and can interact with it through actuators. The term ad hoc refers to a type of network configuration associated with broad networks, such as WiFi. However, this type of network faces different challenges that are not covered in this chapter. The rapid development of low-cost Micro-Electro-Mechanical-Systems has led to a sharp increase in the use of these devices in several fields such as home automation, industry, health, biology, and so on. The number of potential applications is huge. However, the design of these applications is subject to important constraints: power consumption, limited storage, limited computing capacity, low data rate, and so on. A typical scenario for application could be summarized as follows: Nodes are spread out during deployment and each device has a limited radio range. Nodes have different roles assigned to them: data source, data sink and gateway. Two different paradigms exit when trying to identify the main objective of such a network. The classical approach assumes that the main purpose of the network is to transport data from the sources to the sinks (which we could name data transport paradigm). Data often needs more than one hop to reach the sink node. As there is no network manager (ad hoc approach), nodes have to collaborate to form routes through which data can be transmitted. Once the data reaches the sinks, a base station (usually a personal computer) processes the collected information. In this paradigm, cooperation is limited to an exchange of information. In contrast, the new approach