An Intelligent Scheduling Architecture for Mixed Traffic in LTE-Advanced Networks

Introduction

The rapid development in all IP based next generation mobile communication networks, such as Long Term Evolution-Advanced (LTE-A), is expected to support the outburst of high-speed packet based applications. These applications have a large variety of QoS requirements such as reduced latency and packet loss rate and high throughput. Radio Resource Management (RRM) faces challenges when come across such a large variety of conflicting QoS requirements (Zhen, Yu-Kwong, Jianzhou, 2009). This is due to, limited radio resource, rapidly changing wireless channel conditions and ever increasing number of mobile users. Packet scheduling being one of the cores of RRM is very crucial to make an effective utilization of available radio resource (Rehana, 2010). In a scheduling algorithm, variable QoS requirements of different traffic types must be analysed and weighted appropriately to reach at a balanced solution (Zhen, Yu-Kwong, & Jianzhou, 2009).

The classic packet scheduling algorithms are Round Robin (RR), MAX C/I and Proportional Fairness (PF) algorithms. RR algorithm allocates resources cyclically thus achieving the maximum fairness. MAX C/I and PF algorithm exploit multiuser diversity to enhance system throughput. MAX C/I algorithm allocates a Physical Resource Block (PRB) to a user with the highest channel gain on that PRB, and can maximize the system throughput (Harri & Antti, 2009). PF algorithm takes both system throughput and fairness among users into consideration and allocates resources to users based on the ratio of their instantaneous throughput and acquired time averaged throughput (Stefania, Issam, & Matthew, 2009). However, RR, MAX C/I and PF algorithms aim only at improving fairness, system throughput or the trade-off between fairness and system throughput, respectively. QoS requirements, for example delay requirements of RT traffic or minimum throughput requirements of Non NRT traffic, are not considered at all. In the next generation of mobile communication networks, apart from system throughput and user fairness, the crucial point is to fulfill users’ QoS requirements in a multi-service and multi-user mixed traffic environment. This is because of resource contention among users of different traffic types. To allocate radio resources efficiently and intelligently in such complex environments is very challenging.