Scheduling Algorithm Research Based On QoS In LTE-Advanced

In order to cope with the challenges of mobile communication market, meet multi-user's higher demand for QoS with the new business, the 3GPP organization which covering the world's major enterprises and operators put forward the further evolution of the LTE project—LTE-Advanced. It has been the pursuit of people to improve the fairness of data transmission between multiple users, the throughput of the whole cell and edge user's service experience.While the resource allocation scheme and effective data transmission scheme is the key to achieve this goal.This paper which based on the LTE-A system architecture and new technology as the background, studies the QoS resource scheduling algorithm and binding transmission.The paper introduces in detail the development process of LTE-A system, the status of network deployment covering, higher system requirements and key technology of enhancement, focusing on the MAC layer's scheduling function of the base station side and edge user's data transmission function of the user side. combining with the existing scheduling algorithms, meet the demand of the business performance of QoS and improve the system performance in the conditions of limited resources. The main research contents and results of the paper are divided into the following two aspects:First, cell edge user's uplink coverage is limited and aim at the problem this paper put forward a kind of improved TTI Bundling scheme to reduce the service delay. Based on the three schemes of single HARQ transmission, RLC SDU segment transmission and traditional TTI binding transmission,take the small data packets which binding the UE or high-quality transmission into account, in the principle of decoding the minimum number of RV and processing ACK feedback, to inform the UE uplink data packet being received correctly as early as possible.This scheme can greatly reduce unnecessary RV waiting time, thereby reducing the service transmission delay of the TD-LTE system, and improve the spectrum utilization and system throughput.Second, in order to improve the overall throughput and the fairness of data transmission between multi users in the district, this paper brings forward a scheme of LTE-A system downlink resource allocation based on the scheduling metric value. The scheme break the shackles of traditional sequential resource allocation in the resource allocation processing, matching the user and physical resource block, and allocating the RB resources which provide the best service quality to the corresponding user priority, to ensure that the users transmit data in their respective favorable channel as far as possible. Simulation results show that the scheme can effectively improve the system throughput and fairness in the condition of not increasing the packet loss rate, and it is a good choice for LTE-A downlink.