Ad Hoc Networks
Wireless sensor networks

A WSN (Wireless Sensor Network) consists of nodes organized into cooperative network and utilizes ad hoc network topology. Basically, the WSN is similar to the MANET networks in many aspects. The main reason is that both the WSN and the MANET are distinguished by self configuration nature, nodes are connected by means of wireless connection, and the communication between nodes is enabled by multihop networking. Still, the WSN and the MANET networks are different in several fundamental aspects as shown in table.

Comparison of MANET and WSN
Aspect | MANET | WSN
Utilization and applicability | Used by human beings for data transmission, mobile applications, etc. | Embedded in the environment, used for data gathering (e.g., measuring of temperature, ecological monitoring, etc.) and event detection (e.g., detecting of fire, intrusion detection, etc.)
Size of the devices | Handsets, PDAs, laptops | Small sensors (e.g., millimetres)
Amount of nodes in the network | Up to tens or up to hundreds nodes | Up to thousands or more nodes
Main reason for topological changes | Users’ mobility | Failure of the node

Similarly as in case of MANET, the most critical issues of WSN are a proper MAC protocol and effective routing of data. The MAC protocols formerly used in MANET networks are not suitable due to WSN specifics. The main objective is to use protocol that consumes a little power, avoid collisions and has low memory requirements.