Scheduling Algorithms Comparison in HetNet based LTE-A

The paper considers both the basic mechanisms of queue management on the router and the principle of their operation. A comparative analysis of the following queuing mechanisms: FIFO (First-In First-Out), CQ (Custom Queuing), PQ (Priority Queuing), WFQ (Weighted Fair Queuing), CBWFQ (Class Based Weighted Fair Queuing) and LLQ (Low Latency Queuing) based on a number of parameters such as traffic volume, traffic type, service of mixed traffic, enable on router and number of queues was made. The results of analysis showed that each of the queuing mechanisms has its advantages when dealing with certain types of traffic. Whereas in the process of load balancing several interfaces of the router are involved simultaneously the choice of queuing mechanism on each of them will depend on QoS for real-time traffic. Thus in this work the effect of various queue management mechanisms (such as FIFO, PQ, CQ, WFQ, LLQ) to QoS for real-time traffic in the process of load balancing on the router in an IP network was also investigated. The simulation results showed that most of queuing mechanisms (except FIFO and CQ) in the process of load balancing allowed to provide high QoS for real time traffic by reducing the values of delays and jitter and a significant reduction of lost packets for such traffic flows. At the same time the results showed that in the load balancing process, the most efficient queues servicing mechanism is LLQ, which provides the lowest delay for VoIP and the end to-end delay commensurable with the PQ mechanism for video traffic.

유.무선 인터넷 및 하드웨어의 발전으로 인터넷 방송, VoD(Video On Demand)등의 응용 서비스가 증가하면서 QoS(Quality of Service) 보장 문제가 해결해야 될 중요한 이슈로 부각되고 있다. 현재 인터넷은 모든 패킷을 우선순위에 상관없이 FIFO 형태로 전달하는 최선형(Best Effort) 서비스 기법에 근간하고 있기 때문에 보다 안정적인 서비스 지원을 위한 새로운 QoS 프로토콜 개발, QoS 지원 라우터 개발 등의 연구가 진행 중이다. 하지만 이러한 새로운 QoS 기법들은 기존 인프라를 충분히 활용하지 못하고 새로운 하드웨어 및 소프트웨어를 사용해야 하기때문에 고비용, 비효율성의 문제를 수반한다. 이러한 점에 착안하여, 본 논문에서는 기존의 인프라를 최대한 이용하는 클라이언트/서버 기반의 네트워크 적응형 QoS 제어기법을 제안한다. 제안된 Qos 제어기법은 스트리밍 시스템에서 실시간으로 서비스되고 있는 네트워크 대역폭 상태를 파악하여 QoS를 지원하기 때문에 유ㆍ무선 네트워크에 상관없이 적용할 수 있을 뿐만 아니라, 기존의 스트리밍 서비스에서 사용되는 프로토콜들을 이용하기 때문에 저 비용으로 구현할 수 있다. 또한, 스트리밍 서버와 클라이언트에 새로운 모듈 추가만으로 QoS를 지원하기 때문에 라우터나 네트워크 회선의 교체 없이도 QoS를 보장할 수 있는 장점을 지니고 있다. 인터넷의 트래픽이 폭주하는 경우에서 모의실험을 수행한 결과 일반 인터넷 환경에서는 클라이언트의 버퍼 메모리가 비어 스트리밍 재생 시 끊김 현상이 자주 발생하였으나, 제안한 기법을 사용한 인터넷 환경에서는 동영상의 끊김 현상이 없이(seamless) 재생될 수 있는 스트림이 클라이언트 버퍼 메모리에 항상 있음을 확인할 수 있었다. Due to the fast development of wire&wireless internet and computer hardware, more and more internet services are being developed, such as Internet broadcast, VoD (Video On Demand), etc. So QoS (Qualify of Service) is essentially needed to guarantee the quality of these services. Traditional Internet is Best-Effort service in which all packets are transported in FIFO (First In First Out) style. However, FIFO is not suitable to guarantee the quality of some services, so more research in QoS router and QoS protocol are needed. Researched QoS router and protocol are high cost and inefficient because the existing infra is not used. To solve this problem, a new QoS control method, named Network Adaptive QoS, is introduced and applied to client/server-based streaming systems. Based on network bandwidth monitoring mechanism, network adaptive QoS control method can be used in wire&wireless networks to support QoS in real-time streaming system. In order to reduce application cost, the existing streaming service is used in NAQoS. A new module is integrated into the existing server and client. So the router and network line are not changed. By simulation in heavy traffic network conditions, we proved that stream cannot be seamless without network adaptive QoS method.

In this paper, an analysis of priority queuing and scheduling algorithms is presented. The algorithms utilised in the analysis include First in First out, Priority Queuing, and Weighted Fair Queuing. The analysis network includes a video server and client, an FTP server and client, a VoIP system and a HTTP server and client. The traffic pattern and the packet sizes in the various applications were evenly distributed and based on Poisson's Distribution Function. The Markov model implemented utilised the packet arrival rate and the service time as variables and calculated the average waiting time and the length of the queues. The traffic from this network was routed across a link between two routers which were configured to support the applications based on the queuing algorithms. The end to end delay and the packet drop characteristics of each of these queuing models was compared for the simulated network.

In our previous work, we proposed the TNPOSS (To Next-hop Port Sequence Switch) network which can achieve scalable fast forwarding and is suitable for delivering multimedia flows. However, TNPOSS network has no Quality of Service (QoS) tools to provide better QoS guarantee for multimedia flows which often have long-range dependence (LRD) property. To enhance the QoS ability of TNPOSS network, this paper proposes a QoS-enhanced TNPOSS (QTNPOSS) network model by introducing Fractal Leak Bucket (FLB) shaper and Weighted Fair Queuing (WFQ) scheduler into the original TNPOSS network. In the new QTNPOSS network, each packet of multimedia flows is shaped by the FLB when arriving at a node and is scheduled by the WFQ before being outputted. Based on study above, we further analyze the end-to-end (E2E) delay bound of QTNPOSS network by means of the network calculus theory which is an effective mathematical tool on analyzing the worst-case QoS performances of networks. The service curve and the formulation of E2E delay bound of QTNPOSS network are presented and proved. Extensive numerical experiments show that both the LRD property of multimedia flows and the WFQ weight have influences on the E2E delay bound, and the WFQ weight influences the E2E delay bound more greatly than the LRD property does.

인터넷 전화, 인터넷 방송 VPN(Virtual Private Networks), 멀티미디어 서비스 등의 실시간 혹은 대역폭 요구 서비스 등의 실시간 혹은 대역폭 요구 서비스들이 늘어남에 따라 인터넷에서도 서비스 품질(QoS : Quality of Service)에 대한 요구가 중요한 문제가 되었다. 인터넷 응용 서비스의 품질을 보장하기 위하여 통합 서비스, 차등 서비스, 그리고 MIPLS(Multi-Protocol Label Switching) 등의 여러 가지 방안이 강구되고 있다. 본 논문에서는 차등 서비스(DiffServ : Diferentiated Service)를 이용한 QoS 보장 기법의 성능 해석에 대하여 기술하였다. 차등 서비스의 성능이 다양한 입력 트래픽 모델과 WFQ(Weighted Fair Queueing) 가중치에 의하여 어떻게 영향을 받는지 분석하기 위하여, 랜덤, 버스티, 자기유사 입력 트래픽 모델과 다양한 입력 파리미터에 대하여 모의실험과 성능평가를 수행하였다. 성능분석 결과, 사용된 입력 트래픽 모델에 따라 패킷 지연 rqkt과 손실 사이에 상당한 차이가 발생함을 확인할 수 있었다. 그러나, 모든 입력 트래픽 상황에서, EF(Expedited Forwarding)의 성능은 보장이 가능하고, EF와 BE(Best Effort) 클래스의 서비스가 분리가 가능한 것으로 나타났다. 다음으로 성능 합성(Performance Synthesis) 문제에 대하여 기술하였다. 차등 서비스 망에 대한 보존법칙을 유도하고, WFQ 방식에서 자원의 분배(즉, 가중치)에 따른 성능 변화와 동적 행위에 대하여 분석하였다. The requirement for QoS (Quality of Service) has become an important Issue as real-time or high bandwidth services are increasing, such as Internet Telephony, Internet broadcasting, and multimedia service etc. In order to guarantee the QoS of Internet application services, several approaches are being sought including IntServ (Integrated Service) DiffServ(Differentiated Srvices), and MPLS(Multi-Protocol Label Switching). In this paper, we describe the performance analysis of QoS guarantee mechanism using the DiffServ. To analyze how the DiffServ performance was affected by diverse input traffic models and the weight value in WFQ(Weighted Fair Queueing), we simulated and performed performance evaluation under a random, bursty, and self-similar input traffic models and for diverse input parameters. leased on the results of performance analysis, it was confirmed that significant difference exist in packet delay and loss depending on the input traffic models used. However, it was revealed that QoS guarantee is possible to the EF (expedited Forwarding) class and the service separation between RF and BE (Best Effort) classes may also be achieved. Next, we discussed the performance synthesis problem. (i. e. derived the conservation laws for a DiffServ networks, and analysed the performance variation and dynamic behavior based on the resource allocation (i.e., weight value) in WFQ.

Congestion control and reduction is paramount in enhancing the performance and speed of communication networks. Despite its efficiency in improving the speed and performance of communication networks, it is imperative to mention that the technique exhibit several issues, such as scheduling algorithms. This paper presents a comparison of different results associated with different scheduling algorithms. Multisource was used to simulate and test different scheduling algorithms, including First In First Out (FIFO), Random Packet Drop, and Last In First Out (LIFO). The comparison was made by analyzing different results, including the average delay vs arrival rate, average buffer utilization vs arrival rate, and packet loss ration vs arrival rate. According to the results, it is evident that the average buffer utilization and average packet delays increased as the rate of data transmitted through the network increased. There was no significant change noticed in the average buffer utilization in all the three algorithms. However, the packet loss ratio was high in Random Packet Loss algorithm than in both FIFO and LIFO for slower arrival rates below 1000. Similarly, FIFO exhibited a significantly high average packet delay than both LIFO and Random Packet Drop algorithms.

IEEE 802.16 standard supports real time and non-real time services at each node. However, it has flexibility to develop customized scheduling algorithms according to different priority-based traffic's quality of service (QoS) requirements. Hence, it is imperative to obtain optimum scheduling schemes for different kinds of traffic (i.e., services). Earliest due date (EDD) is one of the highly referred scheduling algorithms for real time communication. In this presentation, our study shows that the proposed hybrid algorithms (EDD along with weighted fair queue (WFQ)) in a node gives better performance for real time services instead of EDD only. Moreover, the results reveal that, scheduling schemes from base station (BS) to subscriber station (SS) like grant per SS (GPSS) impacts less delay than grant per connection (GPC)

This paper proposes a dynamic scheduling scheme to provide quality of service (QoS) guarantees in wireless multiple access control (MAC). In order to achieve high bandwidth utilization and QoS guarantee ratio, token models of sources are constructed in the base station (BS) scheduler. A token model weighted fair queuing (WFQ) algorithm is developed to combine loss and delay requirements for uplink scheduling of real-time traffic. Dynamic priorities are implemented in a real-time traffic token model. In addition, an emergency token buffer is used to accommodate the bursty characteristics of rt-VBR (real-time variable bit rate). The backlogged token buffer compensates the backlogged flow suffering from channel error. Simulations are done to demonstrate that our DWFQ scheme can greatly improve both QoS performance and bandwidth allocation efficiency.

Tour guide has an important role toward the tourism business in Bali, they take care the guests since they arrive until they depart from Bali. Therefore a tour guide should be able to give the best quality of service and also improve it if to provide better service in the future. In order to achieve the best quality of service, the government should create a rule which regulate how a tour guide can be a profession in order to provide a better quality of service to the guests who visit Bali. Bali Regional Rule no 5 year 2008 about Tour Guides is a kind of regulation established by Bali Government as a foundation for a Tour Guide in doing their profession. However, in fact there are so many irrelevant services given by a Tour Guide and it was not based on the regulation and it caused the problems in this thesis. Are there any factors that generate a specific license for a tour guide based on Bali Regional Rule no 5 year 2008 about Tour Guides could not be released? How is the application of punishment ofthose tour guides who did not obey the regulation based on Bali Regional Rule no 5 year 2008 about Tour Guides? This research used empiric approach which means that we are doing an approach by solving the problem that we face during the research. In relation with the regulations and law and also the law theories which relevant applied in this research e.g. theory of obeying the law, theory of authority and theory of product quality. In order to show the government’s authority to apply the law and how the regulation is able to guarantee the law and also to ensure that the government regulation can guarantee the tour guide quality to provide the best quality of services.

Long Term Evolution (LTE) was developed by 3GPP to cope with the increasing demand for better Quality of service (QoS) and the emergence of bandwidth-consuming multimedia applications. Today's data transmission networks face extreme challenges in providing high data rate and low latency. Scheduling paradigms such as Round Robin, Best Channel Quality Condition and Proportional Fair are commonly adopted in current LTE downlink scheduling algorithms, but they are far from optimal for satisfying latency requirements. In this paper, we first survey the state of the art downlink scheduling algorithms in LTE and identify their main challenges. We then formulate the LTE downlink scheduling problem as an optimization problem in order to meet the flow deadlines, then incorporate the formulation within the surveyed scheduling algorithms, to produce better performance. We consider strict deadlines for different types of packets with the goal of maximizing resource distribution. Additionally, in our formulation the buffer state for each user is taken into consideration in order to minimize the packet loss. We evaluate the proposed formulation using LTE-Sim and study its positive impact on the existing LTE downlink scheduling algorithms; the performance in terms of QoS, packet loss and fairness is improved throughout all evaluations.

The recent wireless communication networks rely on the new technology named Long Term Evolution (LTE) to offer high data rate real-time (RT) traffic with better Quality of Service (QoS) for the increasing demand of customer requirement. LTE provide low latency for real-time services with high throughput, with the help of two-level packet retransmission. Hybrid Automatic Repeat Request (HARQ) retransmission at the Medium Access Control (MAC) layer of LTE networks achieves error-free data transmission. The performance of the LTE networks mainly depends on how effectively this HARQ adopted in the latest communication standard, Universal Mobile Telecommunication System (UMTS). The major challenge in LTE is to balance QoS and fairness among the users. Hence, it is very essential to design a down link scheduling scheme to get the expected service quality to the customers and to utilize the system resources efficiently. This paper provides a comprehensive literature review of LTE MAC layer and six types of QoS/Channel-aware downlink scheduling algorithms designed for this purpose. The contributions of this paper are to identify the gap of knowledge in the downlink scheduling procedure and to point out the future research direction. Based on the comparative study of algorithms taken for the review, this paper is concluded that the EXP Rule scheduler is most suited for LTE networks due to its characteristics of less Packet Loss Ratio (PLR), less Packet Delay (PD), high throughput, fairness and spectral efficiency.

The buffered crossbar switch architecture has recently gained considerable research attention. In such a switch, besides normal input and output queues, a small buffer is associated with each crosspoint. Due to the introduction of crossbar buffers, output and input contention is eliminated, and the scheduling process is greatly simplified. We analyze the performance of switch policies by means of competitive analysis, where a uniform guarantee is provided for all traffic patterns. The goal of the switch policy is to maximize the weighted throughput of the switch, that is the total value of packets sent out of the switch. For the case of unit value packets (Best Effort), we present a simple greedy switch policy that is 4-competitive. For the case of variable value packets, we consider the Priority Queueing (PQ) mechanism, which provides better Quality of Service (QoS) guarantees by decreasing the delay of real-time traffic. We propose a preemptive greedy switch policy that achieves a competitve ratio of 18. Our results hold for any value of the switch fabric speedup. Moreover, the presented policies incur low overhead and are amenable to efficient hardware implementation at wire speed. To the best of our knowledge, this is the first work on competitive analysis for the buffered crossbar switch architecture.

Low cost broadband services used widely in the recent years increased the demand for multimedia applications. Many of these applications require different quality of service (QoS) in terms of throughput and delay. In the current resource constrained wireless networks, resource management plays a vital role. In order to handle the resources effectively and to increase the QoS, proper packet scheduling algorithms need to be developed. Low latency queuing (LLQ) is a packet scheduling algorithm which combines strict priority queuing (SPQ) to class-based weighted fair queuing (CBWFQ). In this paper, an enhanced low latency queuing (ELLQ) algorithm is proposed in which an additional SPQ is introduced along with the existing SPQ. Further, the QoS is improved by integrating congestion avoidance algorithm with ELLQ. Simulation results using the OPNET modeller show that the proposed algorithm outperforms the existing algorithm in terms of throughput and delay for the multimedia applications.

Weighted Fair Queuing (WFQ) is a packet scheduling technique allowing guaranteed bandwidth services. However, it is very difficult to implement the WFQ for a lot of queues, because the amount of required calculations for WFQ is proportional to the number of queues. Therefore we proposed the simplified WFQ (SWFQ) mechanism which can support a huge number of queues with guaranteeing the provisioned bandwidth for each queue while it requires fewer amounts of calculations by using approximation techniques. To compare the details of SWFQ and WFQ, a series of simulations are conducted. The result of the simulation shows that SWFQ can guarantee the bandwidth for each queue as same as WFQ and also shows that the difference between WFQ and SWFQ can be negligible when the granularity of the quantization for an approximation is sufficiently fine. In conclusion, these results clarify that SWFQ is an effective mechanism which can provide the same characteristics as WFQ.

Health Centers providing the best quality of service can affect consumer satisfaction in using services. If the quality of service, facilities, and promotions consumers offer is unsatisfactory, consumers no longer use Health Center services. This research focuses on consumer satisfaction with the services provided by the Health Center after using these services and what attributes need to be improved to increase customer satisfaction. This study aims to determine patient satisfaction with the services provided by Health Center X. The method used in this study is IPA (Importance Performance Analysis). This method, also known as quadrants analysis, aims to measure the relationship between consumer perception and the priority of improving the quality of products or services. Twenty-one attributes or statements represent each service dimension: tangibles, empathy, reliability, responsiveness, and assurance. For the quality of services provided by the Health Center to be improved, the Puskesmas must make improvements as soon as possible to statements that fall into the categories that need improvement, namely the words "Large car or motorcycle parking," "Officers carry out administrative processes quickly and precisely," "The ability of the Health Center to respond to complaints, criticisms, and suggestions from patients," and "Guarantee of trust given by officers to services." Puskesmas gets a customer satisfaction level value of 79.03%, which means that the performance given by the Health Center to customers or patients is included in the Satisfied category.