Achieving Scalable Capacity in Wireless Networks with Adaptive Power Control

• Authors: Wang Hei Ho;Soung Chang Liew
• Venue: LCN '05 Proceedings of the The IEEE Conference on Local Computer Networks 30th Anniversary
• Year: 2005

The seminar work of Gupta and Kumar [1] showed that multi-hop wireless networks with capacity scalable with the number of nodes, n, are achievable in theory. The transport capacity scales as \Theta \sqrt n, while the capacity scales as \Theta (n) . A subsequent study [2], on the other hand, showed that the capacity of IEEE 802.11 networks does not scale with n due to its carrier-sensing mechanism. This prior work, however, has not considered the use of power control. The main contributions of this paper are three-folds: 1) we provide an analytical framework for deriving the design requirements of adaptive power control strategies; 2) we demonstrate that 802.11 networks are scalable with power control; 3) however, an enhanced MAC protocol called Selective Disregard of NAVs (SDN) can achieve substantially higher capacity with an adaptive power control scheme; in particular, adaptive power control allows SDN to achieve capacity within 75% of the theoretical optimal capacity of infrastructure-mode wireless networks. A reason why adaptive power control works well is that it takes into consideration the fundamental mutual-interference relationships between links in the vicinity of each other, and adjust their relative transmit powers to reduce these interferences to a large extent that is possible theoretically.