Study of Power Management in Adhoc Networks

In wireless communication, idle listening, receiving and transmitting are the main source of consumption of energy. Much research on wireless networks have focused on the power consumption of the wireless nodes, while at the same time how to acquire power from ambient environment is another direction to extend the battery lifetime. Mostly extending the lifetime of WSNs rely on making the electronic circuitry power efficient by incorporating advances in node architecture, transceivers, access protocols and on finite energy sources like batteries. In contrast, WSNs Powered by Ambient Energy Harvesting can also prove to be useful and economical in the long term as they can operate for very long periods of time until hardware failure, because ambient energy can be harvested from the environment perpetually. Although cellular networks account for a rather small share of energy use, lowering their energy consumption appears beneficial from an economical perspective. In the strive for lessening of the environmental impact of the information and communication industry, energy consumption of communication networks has recently received increased attention. According to PSM, each station must announce traffic before its transmission. PSM requires for this purpose a rather large handshaking period to complete the required announcements. This functional behavior puts a heavy constraint on the size of the announcement period and consequently on throughput, delay and more importantly on power consumption. This paper presents a survey on the various power saving techniques used in wireless networking today. The work presented covers topics ranging from the use of energy harvesting techniques at the physical layer to partitioning the load of power hungry computations across multiple devices at the application layer. While research in this area continues to grow, few standards have yet to emerge that incorporate the use of each of these techniques. The types of wireless networks considered include Wireless Local Area Networks (WLANs), Wireless Personal Area Networks (WPANs), and Wireless Sensor Networks. Existing standards for performing power management in each of these networks are discussed, and their effective use is analyzed. The role that these standards play in industry as well as the role played by current research in this area is also introduced.