Adaptive Token Bank Fair Queuing scheduling in the downlink of 4G wireless networks

Traditionally, the research on packet scheduling has focused mostly on QoS and fairness for different QoS classes or different applications, while opportunistic scheduling algorithms have focused on exploiting the time-varying nature of the wireless channels and to provide fairness to the different mobile users. This segregation between packet scheduling and radio resource allocation is not efficient since none of the two types of scheduling algorithms focus both on providing QoS for the applications and exploiting the time-varying characteristics of the wireless channel. For these reasons, it is necessary to merge the scheduling of packets and the allocation of radio resources to design cross-layer scheduling algorithms.; Adaptive Token Bank Fair Queuing (ATBFQ) algorithm is the proposed algorithm for cross-layer scheduling. The ATBFQ is the modified version of the Token Bank Fair Queuing (TBFQ) algorithm which was initially proposed for single carrier time division multiple access (TDMA) systems. It takes higher layer QoS attributes such as priorities, interflow fairness and delay constraints into account. By selecting the user terminals (UTs) in a certain prioritized manner derived from these QoS attributes, we can improve the performance of the UTs suffering from bad interference conditions and shadowing in particular. The ATBFQ algorithm is designed to accommodate the bursty nature of traffic. This is done by the graceful acceptance of traffic profile violation when bandwidth is available, provided the UT does not exceed its bandwidth allocation in the long term. This prevents sudden degradation of QoS experienced by the end user as a result of traffic profile violations or interference in the wireless environment.; For the radio resource allocation, channel feedback is required from every UT at the start of every scheduling instant. Based on the decisions made in the first level of scheduling with QoS provisioning, appropriate resources are assigned to the selected UTs taking into account the channel quality information (CQI). The maximum signal to interference noise ratio (SINR) method is used for the resource allocation where the best chunk is allocated to the selected UT.; The proposed scheduling algorithm is tested in a multicell environment in the presence of intercell interference. The performance is compared to that of the Score Based (SB) algorithm which is a variation of the Proportional Fair (PF) algorithm (the most widely adapted opportunistic fair scheduling technique) and the round robin (RR) method. The performance is studied in the context of the wide area scenario. QoS issues in terms of throughput, packet drop ratios, and queuing delays are addressed. Furthermore, a fairness analysis is shown highlighting the performance of ATBFQ, SB, and RR.; It is observed from simulation results that the proposed scheme provides better fairness in terms of queuing delays, and dropped packets for various loading factors, while the throughput remains comparable. A gain in the performance of cell edge users is also observed in the proposed scheme, this may result in substantial savings in the deployment cost since a fewer number of base stations (BS) will be needed to cover regions.