Topic：Decentralized Power Control for Random Access with Multi-User Detection
Speaker：Xu Chongbin(City University of Hongkong)
XU Chongbin received his B.S. degree in Information Engineering from Xi’an Jiaotong University in 2005 and PhD degree in Information and Communication Engineering from Tsinghua University in 2012. He is now with the information technology group in the Department of Electronic Engineering at the City University of Hong Kong. His research interests are in the areas of signal processing and communication theory, including linear precoding, iterative detection and decoding, and decentralized power control in random access systems.
In multi-user communication systems without central control, random access is a suitable option due to its decentralized nature. This presentation is concerned with the decentralized power allocation problem in random-access systems. Multi-user detection (MUD) is assumed at the receiver to enhance the multi-packet reception (MPR) capability. We consider a decentralized random power transmission strategy, where each user selects its transmit power level randomly according to a power distribution conditioned on its own channel state. Our focus is on the design of this distribution such that the system packet throughput is maximized under rate and power constraints. A main finding is that the supports of the optimal power distributions are of discrete nature. This finding greatly simplifies the distribution optimization problem. Numerical results demonstrate that the proposed scheme can achieve noticeable performance improvement compared with conventional single-user detection (SUD) based ones and offer flexible tradeoff between the system throughput and power consumption.