Abstract :

Multi-carrier communication techniques have been successfully implemented in both wireline and wireless networks, and have becoming the core for 4G mobile communication systems. As a well known example, Orthogonal Frequency-Division Multiplexing (OFDM) has been used in standards such as Digital Subscriber Lines (DSL), Wireless LAN (802.11 a/g), WiMAX (802.16), Digital audio/video broadcasting (DAB/DVB) and Ultra Wideband (UWB). The major benefits of using multi-carrier techniques include high spectrum efficiency and resistance against multi-path interferences. In this talk, we consider power control in two multi-carrier communication systems, which are motived by wireless ad hoc networks and DSL networks, respectively. Although the optimization problems are mathematically similar, we solve each of them differently by fully utilizing the special characteristics of the underlining networks. For the wireless ad hoc network, we propose an Asynchronous Distributed Pricing (ADP) algorithm, with a nice interpretation of distributed Pigovian taxation. Optimality and convergence of the ADP algorithm are shown using supermodular game theory. For the wireline DSL networks, we propose the concept of "reference line", which leads to a low complexity algorithm with near optimal performance.