While spectrum is believed to be precious, it is actually seriously underutilized. According to Ofcom in the UK, over 50% of locations in the UK could have more than 150 MHz of interleaved spectrum available for cognitive access. It is Ofcom's goal to move from the traditional exclusive-use model to a liberalization model in spectrum allocation. In this talk, I will study the distributed resource allocation problem for an orthogonal frequency-division multiple-access (OFDMA) interference channel in which every user is free to access any of the frequency channels and users inherently compete and interfere with each other. I will take a game-theoretic perspective of the channel and view the network as individuals interacting with the environment composed of the reactions from competitors. Competition among selfish individuals is bound to result in the tragedy of the commons, with users harmfully interfering with each other without a proper reconciliation mechanism. Inspired by the Stackelberg leadership model of a strategic game, I propose to inject environmental foresightedness to users by introducing the role of environmental interference derivative in one's action (or strategy). As a major result, I will present a physical property of the OFDMA resource allocation game which permits users to be foresighted for a much more effective reconciliation for maximizing their rates, based on only local channel state information (l-CSI) at the user level. The outcome is a simultaneous water-filling game regulated by a carefully chosen operational interference derivative. Simulation results will be provided to show that the proposed game can achieve the network sum-rate close to the near-optimal centralized solution. The talk will be concluded by a discussion of using the strategic game for a primary-secondary cognitive radio network.

Kai-Kit Wong received the BEng, the MPhil, and the PhD degrees, all in Electrical and Electronic Engineering, from the Hong Kong University of Science and Technology, Hong Kong, in 1996, 1998, and 2001, respectively. After graduation, he took up academic and research positions at the University of Hong Kong, Lucent Technologies, Bell-Labs, Holmdel, the Smart Antennas Research Group of Stanford University, and the University of Hull, UK. At present, he is Reader in Wireless Communications at the Department of Electronic and Electrical Engineering, University College London, UK.

 

He is Senior Member of IEEE and is also on the editorial board of several international journals including the IEEE Wireless Communications Letters, IEEE Communications Letters and IEEE Signal Processing Letters. His current research interests center around cognitive radio, cooperative wireless networks, performance analysis of single and multiuser MIMO channels and physical-layer security analysis and optimisation.