Grouping Based Proportional Fair User Schedule Algorithm in MU-CoMP

Aiming at improving the system uplink transmitting and fairness performance, a novel grouping based proportional fair schedule algorithm is proposed. By dividing users into several groups, computation complexity in user selecting is reduced. Proportional fair mechanic provides more fairness among users, preventing users from starving of transmitting. Simulation results show that the proposed algorithm improves the uplink CoMP system’s sum capacity while keep all users in a quite fair state. Introduction In the LTE-Advanced system, Cooperated Multi Point (CoMP) technology becomes very popular because of its capability on canceling inter cell interference. Recent researches on the CoMP can be classified into uplink CoMP (U-CoMP) and downlink CoMP (D-CoMP). In this paper, we mainly discuss a novel scheduling algorithm about U-CoMP. In the modern mobile communication system, MIMO technology is playing an important part in increasing the system capacity due to its spatial multiplexing and diversity gain. However, the deployment of multi antennas on the mobile equipment is limited due to the costs and technical difficulties. Even the devices that have already been equipped with multi antennas have little performance increase due to the spatial correlation of antennas. In this situation, the multi user CoMP (MU-CoMP) was proposed. In a MU-CoMP system, two or more single antenna devices are united to form a virtual MIMO system with the base station. Been scheduled by the base station, all users in the system transmit their signals using the same time and frequency resource in an orderly manner. Recent researches in the MU-CoMP mainly focus on the user pairing scheme. Scheduler of the base station, i.e. the E-Node B, dispatches user pairs during the scheduling period. Notel proposed two types of user pairing and scheduling method in [1], including the random user pairing scheduling and orthogonal user pairing scheduling, and the orthogonal user pairing scheduling can be implemented under the orthogonal formula and determinant formula criteria. A SNR based paring scheduling method is proposed in [2]. In these works only the system performance is considered, but the fairness is ignored. Chen, etc. presented a novel user pairing algorithm in [3], in which double proportional fair (PF) method is used, and the system performance was improved. Many newly user pairing algorithms were proposed based on Chen’s work, but these works still aim at user pairing. In the realistic environment, the amount of users in a single cell is usually very large, especially in some hot spots, the larger the amount of users is, the more the count of user pairs will be, then the payload of the scheduler in the E-NodeB would significantly increase. This may be one of the side effects of the user pairing scheme. On the other hand, by using user pairing scheme, only two users are dispatched in the same schedule slot, thus the system resources are not made full use. It has been proved in [4] that the multiplexing of the same time frequency resource block by multiple users will significantly increase the system performance, when the count of transmitting antennas is less than that of the receiving antennas. In this paper, a user grouping based proportional fair (GPF) schedule algorithm is proposed. By dividing users into several groups, the computational complexity is reduced. Furthermore, a better tradeoff between the fairness and system performance is achieved. System Model International Conference on Automation, Mechanical Control and Computational Engineering (AMCCE 2015) © 2015. The authors Published by Atlantis Press 2148 In this paper, we consider a single cellular cell scenario as shown below. E-NodeB Transmission Group UE UE UE User Group