A Stable User Pairing Scheme In VMIMO System Based On Game Theory

Nowadays, mobile terminals become the major ingress of Internet, and we are nowentering an era of mobile Internet. The need of increasingly faster and more reliable datatransmission in this era brings challenges for developong high-speed wirelesscommunications technology with higher system capacity. In the meanwhile, the existingwireless communication systems have hungrily occupied the scarce and limited radioresources. How to improve system reliability and capacity in the limited time/frequencyresources, become an important research topic in the field of wireless communications.The multiple-input multiple-output (MIMO) technology can significantly improve thereliability and capacity of the communication system with a diversity gain and a multiplexinggain. Thus, MIMO technology has been widely used in LTE. However, the implementation ofMIMO requires installing multiple antennas in a wireless device. The limits in complexity andsize of mobile terminals with multiple antennas constrain its future applications. VirtualMIMO (VMIMO), which requires only one antenna in one terminal, was then proposed toexploit spatial diversity via antenna sharing among distributed mobile users. Therefore,Virtual MIMO has also been widely used in LTE and WiMAX communication systems. Thekey step to implement virtual MIMO is user grouping algorithm, which directly affect theperformance of the entire virtual MIMO system.In this paper, we consider a2×2VMIMO system, where two users are paired together tocommunicate with the base station simultaneously. The contributions in this paper include:First, we summarize the status of the development of modern wireless communicationtechnology and motivate the research on MIMO and virtual MIMO technologies. Then westudy several existing user pairing algorithm in2×2VMIMO system, with the analysis oftheir advantages and disadvantages. Based on the coalitional games theory, we formulate thepairing problem in the2×2VMIMO system into a symmetric pairing game and point out theimportance of the stable pairing. Finally, we develop a symmetric stable pairing (SSP)algorithm to find out the stable pairing. Simulation results show that the stable pairing givenby SSP results in a high system capacity and an acceptable fairness.