QoS Oriented Time and Frequency Domain Packet Schedulers for The UTRAN Long Term Evolution

Abstract

In this paper we introduce Orthogonal Frequency Division Multiple Access (OFDMA) downlink general packet scheduling methods for throughput fairness control among users. The investigation is based on the 3GPP UTRAN Long Term Evolution (LTE) and a decoupled time/frequency domain packet scheduler approach is used. It is shown that fairness can be effectively controlled with frequency domain metric weighting or Time Domain Priority Set Scheduling (TD-PSS) depending on the number of users in the cell. Furthermore we introduce a principle of metric decoupling between time and frequency domain schedulers that is fundamental for maximizing throughput control. The algorithms are simulated in Best Effort (BE) and Constant Bit Rate (CBR) users conditions. They are shown to provide coverage gains of up to 60% for a cell throughput loss of 5% over the well known time-frequency domain proportional fair scheduler.

Performance Analysis of Scheduling Strategies in LTE based on Open-Loop Spatial Multiplexing MU-MIMO Transmission Mode

“…The figure (13) shows the UE throughput ECDF distribution curve for 4x2 antenna configurations, here the RR and the PF schedulers has approximately the same distribution curves, while the best CQI shows an average distribution of throughput per UE. Here the general throughput for (4x2) shown in figure (14) and the fairness results, the result is similar to (2x2) results but with some different, is that here the RR and PF schedulers has the same throughput results, and fairness values.…”

“…LTE physical layer is important for conveying both data and control information between an eNodeB and UE. To enable reproducibility of our results, simulation of the network is done by using a system level simulator [9,[11][12][13][14].…”

Impact of the LTE scheduler on achieving good QoE for DASH video streaming

“…The scheduling metric of users with average rate less than the target rate is estimated using TD BET while the other users' metric is estimated using the TD PF metric. The scheduler then multiplex a number of users with the highest metric from both groups are scheduled using FD scheduler as detailed in [9]. Token bank fair queue is another QoE-aware scheduler that is designed to guarantee a minimum rate for different users.…”

Downlink Resource Scheduling in an LTE System

“…Note that the metrics used for TD and FD scheduling can be different in order to provide a greater degree of design flexibility. Examples of TD/FD scheduling metrics have been proposed in Kela et al (2008); Monghal et al (2008). In order to make good scheduling decisions, a scheduler should be aware of channel quality in the time domain as well as the frequency domain.…”

“…This additional flexibility has been shown to provide throughput and coverage gains of around 40% Pokhariyal et al (2006). Because packet scheduling for LTE involves scheduling users in both TD and FD, various TD and FD schemes have been proposed in Pokhariyal et al (2006)-Monghal et al (2008. Assume that we have packets for N users users waiting in the queue and that resources can only be allocated at the beginning of a pre-defined time period known as the Transmission Time Interval (TTI) or scheduling period.…”