LTE optimization and resource managment in wireless heterogeneous networks

Mobile communication technology is evolving with a great pace to offer richer user experience and make an operator’s business more profitable at the same time. The development of the Long Term Evolution (LTE) mobile system by 3GPP is one of the milestones in this direction. 3GPP specifications for LTE mobile systems serve as the high level standards leaving room for improvements by researchers. This work highlights a few of such areas in the LTE radio access network where the proposed innovative mechanisms can substantially improve overall system performance. This includes a novel air interface scheduler design which can coordinate with the core network entities to avoid imminent network congestion. Another proposed air interface scheduling algorithm exhibits an adaptive behavior and reacts to network load conditions in optimizing the scheduler operations. Similarly, packet queue management for buffers of the LTE air interface scheduler is an important subject which has significant impact on user perceived QoE and inter-site handover operations. The thesis discusses all these topics in great detail and proposes practical solutions which are proven to be effective with the help of simulation based analysis. The advent of mobile devices with multiple radio interfaces has increased the opportunity for users to stay connected through any available network type. This makes operators realize that the integration of 3GPP networks (e.g., LTE, HSPA etc.) and non-3GPP networks (e.g., WLAN, WiMAX etc.) is inevitable. This integration would enable operators to offload the select user traffic from 3GPP networks to the integrated WLAN networks with overlapped coverage. However, it comes with the responsibility of the operators to actively manage the bandwidth resources of the two network types in order to get most out of this integration. The thesis addresses this issue in immense detail. For this purpose, a comprehensive system architecture is developed as an overlay of the 3GPP defined SAE architecture. The proposed architecture serves as a framework for implementing network bandwidth resource management mechanisms. In addition, this work also proposes several resource management mechanisms which can operate in conjunction with the purported overlay system architecture. The performance of these mechanisms is evaluated using a heterogeneous network simulator, developed by the