Research On The Semi-persistent Scheduling For VoLTE

Vo LTE(Voice over LTE)is the ultimate voice solution of 4G mobile system,all mobile operators will transfer their voice communication to Vo LTE platform to enhance the user's voice experience.In Vo LTE system,reasonable scheduling algorithm in MAC layer will highly enhance the performance of Vo LTE transmission and the user experience as well.In LTE standard,the semi-persistent scheduling algorithm is adopted for Vo LTE transmission,but the first-come-first-served scheduling mechanism cannot achieve high wireless resource utilization rate and just get a reasonable fairness.In this thesis,a feedback aware priority based semi-persistent scheduling algorithm was proposed.The proposed algorithm takes into account the factors of weighted packet delay,PRB(Physical Resource Block)number,average channel quality,average throughput,so it can achieve a higher capacity,higher fairness,lower packet loss,and just a little performance loss in transmission delay.The main work of this thesis is as follows:1.Introduced the priority mechanism of dynamic scheduling into the Vo LTE semi-persistent scheduling algorithm to enhance voice performance.2.Both semi-persistent scheduling algorithms based on channel quality and delay were introduced;Rationalities and shortcomings of the priority parameters were also analyzed.3.Based on channel state information and service information,we proposed a feedback aware priority based semi-persistent scheduling algorithm.The main parameters,such as weighted packet delay,PRB(Physical Resource Block)number,average channel quality,average throughput,were investigated in detail;the scheduler model and scheduling process were described thoroughly.4.The simulation model of the proposed algorithm was built based on LTE-sim,an open source LTE system level simulator.Several Schedulers were simulated and compared.Compared with three others semi-persistent scheduling schemes,the proposed algorithm has gained 6.3% capacity increase,6.0% fairness increase,13.1% packet loss rate decrease at the cost of increasing 5.6% of packet delay,which can conduct telecommunications operators to design benign scheduling algorithm in e Node B.