QoS-provisioning downlink resource management in 4G cellular systems

Long term evolution (LTE) has become one of the dominating communication standards for 4G cellular systems. It employs the orthogonal frequency division multiple access (OFDMA) technique to enhance the efficiency of downlink transmissions, which divides the communication spectrum into multiple resource blocks. How to efficiently distribute these resource blocks among user equipments (UEs) is a challenging issue, which also significantly affects the system performance of LTE. Furthermore, in order to provide different quality of service (QoS) for various types of traffic flows, LTE defines two categories of traffic flows: guaranteed bit rate (GBR) and non-guaranteed bit rate (non-GBR). In the paper, we develop an efficient resource management mechanism to allocate downlink resource blocks to UEs so as to support QoS for GBR traffic flows while avoid starving non-GBR traffic flows. Our mechanism takes into account various network conditions such as channel quality, head-of-line (HOL) packet delay, QoS class identifier (QCI) value, and buffer length. Through the LTE-Sim network simulator, we demonstrate that the proposed mechanism can reduce both packet dropping and delay of GBR traffic flows. In addition, non-GBR traffic flows can still keep relatively high throughput to improve system performance.