Novo escalonador para rede LTE

Abstract

The LTE network was developed to provide communication between terminals with voice, video and data applications with QoS (Quality of Service). One of the ways to provide QoS is through a packet scheduler. The LTE specification do not define the development of the scheduler, which is responsible to select a user in a certain time slot. Several schedulers have been proposed in the literature, such as Proportional Fair, Modified Largest Weighted Delay First, Exponential Proportional Fair, Frame Level Scheduler, among others. As it has not been found to date a scheduler that guarantees the delay requested by the user and determines the number of users in the system to guarantee this delay, the work proposes a new downlink packet scheduler to achieve these goals. First, two algorithms were used in the model adapted for LTE network, being the token bucket to shape the user input traffic preventing packet congestion along with the Latency Rate (LR) server that provides the parameters of the user service rate and the amount of user to ensure the requested delay. With the token bucket values stipulated from the maximum packet size of the LTE network, the incoming traffic from the users video stream was wrapped. The size of the token bucket, the token bucket rate, and the requested user delay were entered into the LR server to obtain the user service fee and the amount of users in the system. The user service rate was implemented in the PF scheduler algorithm to generate the new user allocation metric. The new scheduler PFLR (Proportional Fair - Latency Rate) was implemented in the LTE-Sim simulator and executed simulations comparing with the PF and MLWDF schedulers. The simulations performed were the average delay per user, average throughput per user, packet loss and fairness. Through the results it was possible to prove the advantages of the PFLR scheduler in guaranteeing the delay requested by the user.