On Design and Analysis of Channel Aware LTE Uplink and Downlink Scheduling Algorithms

Abstract

In the past two decades, there has been a drastic increase in the mobile traffic, which is caused by the improved user experience with smart phones and its applications. In LTE system, the packet scheduler plays a vital role in the effective utilization of the resources. This field is not standardized and has immense scope of improvement, allowing vendor-specific implementation. The work presented in this thesis focuses on designing new scheduling algorithms for uplink and downlink to effectively distribute resources among the users. LTE scheduling can be categorized into two extremes, namely, Opportunistic scheduling and Fairness scheduling. The Best Channel Quality Indicator (BCQI) algorithm falls under the former category while Proportional Fairness (PF) algorithm under the later. BCQI algorithm provides high system throughput than PF algorithm, however, unlike BCQI algorithm, PF algorithm considers users with poor channel condition for allocation process. In this work, two new scheduling disciplines referred as Opportunistic Dual Metric (ODM) Scheduling Algorithm is proposed for uplink and downlink respectively. The objective of the algorithm is to prioritize the users with good channel condition for resource allocation, at the same time not to starve the users with poor channel conditions. The proposed algorithm has two resource allocation matrices, H1 and H2, where H1 is throughput-centric and H2 is fairness-centric. The uplink algorithm uses the two resource allocation matrices to allocate the resources to the users and to ensure contiguous resource allocation. The downlink algorithm is an extension of the proposed uplink algorithm avoiding uplink constraints. The downlink algorithm employs the two resource distribution matrices to provide an efficient resource allocation by expanding the allocation for the users considering intermittent resources. The performance of ODM is measured in terms of throughput, fairness. Additionally, the uplink algorithm is analysed in terms of transmit power. From the results it is observed that the proposed algorithms has better trade-off in terms of all the performance parameters than PF scheduler and BCQI scheduler.