A Downlink Scheduling Approach for Balancing QoS in LTE Wireless Networks (original) (raw)
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QoS-Aware Proportional Fair (QAPF) Downlink Scheduling Algorithm for LTE Network
Long Term Evolution (LTE) supports several QoS (quality of services) classes and tries to guarantee their requirements. There are two main different QoS classes: Guaranteed Bit rate (GBR) such as VoIP and non-Guaranteed Bit Rate (non-GBR) such as FTP or HTTP. Having these different QoS requirements in packet domain introduces an additional challenge on the LTE MAC scheduler design. Therefore, the scheduler has to be aware of the different service requirements and satisfy them. In this paper, QoS aware proportional fair downlink scheduler (QAPF) is proposed. It can optimize the use of available resources while maintaining QoS requirements of different service classes. The result will show the performance evaluation of the proposed scheduler by comparing with others.
Performance Evaluation of Proportional Fairness Scheduling in LTE
In 3GPP LTE OFDMA cellular systems, radio resource scheduling schemes are significant processes in which the available scarce and prohibitively expensive radio resources are assigned to each active user efficiently in terms of quality of service (QoS). An efficient scheduling algorithm plays an important role for effective utilization of radio resources, high data rate, low latency, fairness among users within a system as well as for the entire system performance. This paper evaluates the performance of three basic packet scheduling algorithms in downlink 3GPP LTE cellular network under universal frequency reuse scheme by executing a simulation in different channel conditions in terms of maximum throughput and fairness metrics.
QOS Downlink Schedulers in LTE towards 5G Network
— LTE is expected to be the dominant system used by operators in these years due to its promising solutions for achieving high capacity and data rate. However, LTE packet scheduling and distributing resources among users is still the main challenge due to unfairness and low performance which occur when allocating resources to users. In this paper, the above mentioned challenges are studied and analysed, focusing on three schedulers; they are Proportional Fair (PF), Maximum Throughput (MT) and Blind equal throughput (BET). These methods do not provide QoS to users that use different types of traffic flows. The proposed algorithm in this paper is to modify the PF scheduler in order to fulfil the QoS criteria maximizing throughput and minimizing the delay for real time service. VoIP and video have been selected as real time traffic and best effort as non-real time. LTE-Sim simulator is used to compare between the mentioned schedulers in terms of throughput, delay, packet loss ratio and spectrum efficiency.
Eurasip Journal on Wireless Communications and Networking, 2009
Designing scheduling algorithms at the medium access control (MAC) layer relies on a variety of parameters including quality of service (QoS) requirements, resource allocation mechanisms, and link qualities from the corresponding layers. In this paper, we present an efficient cross-layer scheduling scheme, namely, Adaptive Token Bank Fair Queuing (ATBFQ) algorithm, which is designed for packet scheduling and resource allocation in the downlink of OFDMA-based wireless 4G networks. This algorithm focuses on the mechanisms of efficiency and fairness in multiuser frequency-selective fading environments. We propose an adaptive method for ATBFQ parameter selection which integrates packet scheduling with resource mapping. The performance of the proposed scheme is compared to that of the round-robin (RR) and the score-based (SB) schedulers. It is observed from simulation results that the proposed scheme with adaptive parameter selection provides enhanced performance in terms of queuing delay, packet dropping rate, and cell-edge user performance, while the total sector throughput remains comparable. We further analyze and compare achieved fairness of the schemes in terms of different fairness indices available in literature.
A QoS-aware downlink packet scheduler using token bucket algorithm for LTE systems
2014 22nd Iranian Conference on Electrical Engineering (ICEE), 2014
LTE is one of the leading technologies to meet the requirements of 4G telecommunication systems. Important design parameters intended to achieve this goal include high data rate, low latency and efficient network bandwidth requirements. Scheduling in LTE is one of the most important functions of the eNodeB due to the existence of different subcarriers in OFDMA modulation and the frequency diversity of the channel. However, the scheduling algorithms are not defined by the Third Generation Partnership Project (3GPP) and are left open for designers and manufacturers. In this paper, we propose a novel QoS-Aware scheduling algorithm in which a Token Bucket algorithm is used in order to limit the access to the resources used by the real time traffic. Simulation results show that the Token Bucket algorithm, by limiting the amount of resources allocated to real time and high priority traffic streams, causes other type of traffic not to be starved. This feature of the scheduling algorithm not only increases the efficiency of the frequency utilization, but also causes the QoS requirements of various traffic classes to be satisfied.
Proportional fair scheduling algorithm in OFDMA-based wireless systems with QoS constraints
Journal of Communications and Networks, 2000
In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.
International Journal of Advanced Computer Science and Applications, 2016
The Long Term Evolution (LTE) is a high data rates and fully All-IP network. It is developed to support well to multimedia services such as Video, VoIP, Gaming, etc. So that, the real-time services such as VoIP, video, etc. need to be optimized. Nevertheless, the deployment of such live stream services having many challenges. Scheduling and allocating radio resource are very important in LTE network, especially with multimedia services such as VoIP. When voice service transmitted over LTE network, it is affected by many network impairments where there are three main factors including packet loss, delay, and jitter. This study proposes a new scheduler which is based on VoIP priority mode, Wideband (WB) E-model, QoS-and Channel-Aware (called WE-MQS-VoIP Priority scheduler) for voice services in LTE downlink direction. The proposed scheduling scheme is built based on the WB E-model and Maximum Queue Size (MQS). In addition, we integrate the VoIP priority mode into our scheduling scheme. Since the proposed scheduler considers the VoIP priority mode and user perception, thus, it improves significantly the system performance. The results demonstrate that the proposed scheduler not only meets QoS demands of voice calls but also outperforms Modified Largest Weighted Delay First (M-LWDF) in terms of delay, Packet Loss Rate (PLR) for all number of user (NU) and excepting NU equals 30, respectively. For Fairness Index (FI), cell throughput, and Spectral Efficiency (SE), the difference among the packet schedulers is not significant. The performance evaluation is compared in terms of Delay, PLR, Throughput, FI, and SE.
2018
The introduction of Machine to Machine (M2M) communications in future cellular networks will be subject to considerable degradation in the performance of existing traditional Human to Human (H2H) applications. However, with the ever increasing data traffic, resource allocation and traffic management, while maintaining quality of service, are a major challenge in terms of terminal fairness and throughput. In this paper we are interested in the allocation of radio resources in downlink Long Term Evolution (LTE) network including a comparative study between six scheduling algorithms which are: Proportional Fair (PF), Exponential Proportional Fair (EXP/PF), Maximum Largest Weighted Delay First (MLWDF), Frame Level Scheduler (FLS), Exponential Rule (EXP-RULE) and Logarithmic Rule (LOG-RULE). We considered the real-time flows (video and voip) in terms of throughput, goodput, fairness index and spectral efficiency, in order to have a clearer view of the quality of experience provided by th...
Downlink Scheduling for Multiclass Traffic in LTE
Eurasip Journal on Wireless Communications and Networking, 2009
We present a design of a complete and practical scheduler for the 3GPP Long Term Evolution (LTE) downlink by integrating recent results on resource allocation, fast computational algorithms, and scheduling. Our scheduler has low computational complexity. We define the computational architecture and describe the exact computations that need to be done at each time step (1 milliseconds). Our computational framework is very general, and can be used to implement a wide variety of scheduling rules. For LTE, we provide quantitative performance results for our scheduler for full buffer, streaming video (with loose delay constraints), and live video (with tight delay constraints). Simulations are performed by selectively abstracting the PHY layer, accurately modeling the MAC layer, and following established network evaluation methods. The numerical results demonstrate that queue-and channel-aware QoS schedulers can and should be used in an LTE downlink to offer QoS to a diverse mix of traffic, including delay-sensitive flows. Through these results and via theoretical analysis, we illustrate the various design tradeoffs that need to be made in the selection of a specific queue-and-channel-aware scheduling policy. Moreover, the numerical results show that in many scenarios strict prioritization across traffic classes is suboptimal.
A QoS-Aware Scheduling Algorithm Based on Service Type for LTE Downlink
In this paper, a resource scheduling algorithm for Long Term Evolution (LTE) downlink is proposed. It provides Quality of Service (QoS) guarantee to Guaranteed Bit Rate (GBR) services and also suit to the Non Guaranteed Bit Rate (Non-GBR). Different services possess different QoS needs in LTE system, based on this, 3GPP divide them into several types. In view of the division, we set priorities for different kinds of services to guarantee the transportation of GBR services which have high QoS needs. At the same time, we take the Media Access Control (MAC) layer logical channel priority into account, and consider users' channel quality to acquire a higher cell throughput. Simulation results show that our scheme can improve the QoS of emergency services obviously at the cost of a certain amount of the non-real times'.