Comparing power consumptions of collaborative and non-collaborative systems

In a collaborative wireless network, communicating nodes collaborate in routing and/or improving the quality of transmission of each other´s packets. This is especially useful when the channel between a pair of nodes is in a deep shadow-fading state. In this situation, increasing the power level may either not resolve the problem or be too power consuming, while generating interference for other receivers on the same channel. A collaboration node, which has good propagation channels to both the source and the destination, may be used to relay the packets between them. The average amounts of power consumed by nodes in a standard wireless network that uses single-hop transmission and a collaborative wireless network that uses two-hop transmission is compared. It is shown that under certain conditions the ratio of the average power consumptions in the two networks, when N collaborating nodes on average are available for each node, can be approximated by k ln N + q. The constant k and q are related to the propagation channel. For a Nakagami fading channel with parameter m, k = 1/ln m and q = 1, while for a shadowing channel with standard deviation /spl sigma//sub dB/, k = /spl sigma//sub dB/ / /spl radic/ /spl pi/ and q = 0.23 /spl sigma//sub dB/.