Transmission power control techniques for MAC protocols in wireless sensor networks

Communication is usually the most energy - consuming event in wireless sensor networks (WSNs). The lifetime of these networks is determined by the capacity of batteries and one of the biggest challenges is to reduce the energy consumed in the communication. Several techniques to reduce the energy consumption have been proposed in routing protocols: diminish the traffic of data, optimize the routes or the control of the topology. However, the management and operation of the node´s radio is responsibility of the medium access control (MAC) protocol. This thesis presents four new transmission power control (TPC) techniques for MAC protocols in WSNs. These techniques are based on the interaction between sensor nodes and take into account the limitations of resources such as processing, memory and energy in the calculation of the minimum of transmission power. To evaluate these techniques, four MAC protocols had been developed: iterative, attenuation, AEWMA and hybrid. The Iterative was the first MAC protocol with TPC developed exclusively for WSN. These protocols have been experimented in the Mica Motes2 platform, in diverse scenarios varying parameters such as internal and external environment, the distance among the communicating nodes, the occurrence of simultaneous transmissions, the use of multi-hop transmissions and node mobility. Results have shown that TPC protocols reduce the energy consumption by up to 57% in comparison to the protocols with fixed transmission power. Moreover, the protocols with TPC increase the throughput of the network while maintaining a very high delivery rate.