Traffic Sensitive and Traffic Load Aware Path Selection Algorithm For MMR WIMAX Networks

The recent developments in the broadband wireless access (BWA) communication systems have introduced several major changes to the existing systems. Legacy IEEE 802.16j is one such amendment to the existing IEEE 802.16 WiMAX family. The key modification introduced by 802.16j system is the concept of relay station (RS), which may be used to enhance the system coverage or to make system throughput optimal. The end terminals, subscriber stations (SS) are unchanged in the standard. The overall change pertinent to the system has raised many unresolved issues related to RS and multi-hop relay base station (MR-BS). The selection of path from a SS to MR-BS via a RS is also one of the issues, need to be addressed. The path selection of a SS in both uplink and downlink directions is left open in the standard. It is very significant to satisfy the traffics of stringent quality of service (QoS) requirements and to appropriately manage the resources of a cell under different circumstances. This paper proposes a path selection algorithm to achieve the aforementioned qualities in the network. The path selection metrics include traffic load of the transparent relay station and traffic sensitivity factor of the SS. An extensive simulation work discusses the performance evaluation of the proposed work using QualNet simulator

USING THE CONCEPT OF A MAC SCHEDULING ALGORITHM FOR WIMAX NETWORKING ARCHITECTURE

Wimax is wireless digital communication system which is intended for wireless Metropolitan area networks. Wimax standsfor worldwide interoperability for microwave access. Wimax Technology enables ubiquitous delivery of wireless broadbandservice for fixed and or mobile users. An IEEE 802.16 wireless system can provide broadband wireless access to subscriberstations and operate in mesh mode. The communication between a subscriber station and a base station can pass through oneor more intermediate subscriber stations. The IEEE 802.16 standard provides a centralized scheduling mechanism thatsupports contention-free and resource-guarantee transmission services in mesh mode. This paper show how MAC schedulingarchitecture is emphasized for IEEE 802.16 standards.Keywords: MAC, QoS class scheduling, IEEE 802.16, WiMax, Network

Connectivity in mobile multihop relay network

Mobile Multihop Relay (MMR) network is an attractive and low-cost solution for expanding service coverage and enhancing throughput of the conventional single hop network. However, mobility of Mobile Station (MS) in MMR network might lead to performance degradation in terms of Quality of Service (QoS). Selecting an appropriate Relay Station (RS) that can support data transmission for high mobility MS to enhance QoS is one of the challenges in MMR network. The main goal of the work is to develop and enhance relay selection mechanisms that can assure continuous connectivity while ensuring QoS in MMR network using NCTUns simulation tools. The approach is to develop and enhance a relay selection for MS with continuous connectivity in non-transparent relay. In this approach, the standard network entry procedure is modified to allow continuous connectivity with reduced signaling messages whenever MS joins RS that is out of Multihop Relay Base Station (MRBS) coverage and the relay selection is based on Signal to Noise Ratio (SNR). The QoS performances of the proposed relay selections are in terms of throughput and average end-to-end (ETE) delay. The findings for the proposed relay selection in non-transparent relay shows that the throughput degradation between low mobility MS (30m/s) and high mobility MS (50m/s) is only about 2.0%. The proposed relay selection mechanisms can be applied in any high mobility multi-tier cellular network

Routing and Scheduling Using Column Generation in IEEE 802.16j Wireless Relay Networks

Worldwide Interoperability for Microwave Access (WiMAX) has become an important standard in wireless telecommunication networks in recent years due to the increasing bandwidth requirements, as well as to customer demand for having ubiquitous access to the network. One of the most recent versions of WiMAX is IEEE 802.16-2009, but in this thesis we work with its 802.16j amendment. This amendment includes the use of relay stations (RS) to improve the network's throughput, with the RSs becoming intermediaries between the base station (BS) and the subscriber stations (SS). In the literature, there have been several authors claiming to perform joint routing and scheduling in wireless networks using the column generation technique. Nevertheless, these papers are not performing scheduling since they do not specify how time slots are allocated to each transmitting node over time (they only count the time slots it takes to transmit data). That is why we developed an optimization model (that is solved using column generation) having in mind the fact of performing real scheduling, not only counting time slots but taking into account the allocation of resources over a period of time. The model we developed chooses among a set of possible configurations (a set of transmitting links over a predetermined period of time slots) to calculate the time it takes to transmit data from end to end. After obtaining some simulation results with our model, we compared them with those of a model that does not perform real scheduling. The results show only minor differences in the total number of time slots that a transmission lasts since we can only assign a small number of time slots per configuration

이동통신 네트워크에서의 QoS 패킷 스케줄러 설계 및 고정 릴레이 관련 주파수 재사용 관리 기법 연구

학위논문 (박사)-- 서울대학교 대학원 공과대학 전기·컴퓨터공학부, 2017. 8. 박세웅.The main interest of this paper is to understand a basic approach to provide more efficient method to allocate radio resources in the mobile communication systems, especially in which radio resources could be allocated by both frequency and time division multiple access. So, we consider OFDMA system and the ideas described in this paper could be easily applied to the current and next generation mobile communication systems. This paper studies two basic research themesa QoS packet scheduler design and fixed relay resource management policies based on frequency reuse in mobile networks. This paper considers novel scheduler structures that are executable in the environments of multiple traffic classes and multiple frequency channels. To design a scheduler structure for multiple traffic classes, we first propose a scheduler selection rule that uses the priority of traffic class and the urgency level of each packet. Then we relax the barrier of traffic class priority when a high priority packet has some room in waiting time. This gives us a chance to exploit multiuser diversity, thereby giving more flexibility in scheduling. Our considered scheduler can achieve higher throughput compared to the simple extension of conventional modified largest weighted delay first (MLWDF) scheduler while maintaining the delay performance for QoS class traffic. We also design a scheduler structure for multiple frequency channels that chooses a good channel for each user whenever possible to exploit frequency diversity. The simulation results show that our proposed scheduler increases the total system throughput by up to 50% without degrading the delay performance. This paper also introduces radio resource management schemes based on frequency reuse for fixed relay stations in mobile cellular networks. Mobile stations in the cell boundary experience poor spectral efficiency due to the path loss and interference from adjacent cells. Therefore, satisfying QoS requirements of each MS at the cell boundary has been an important issue. To resolve this spectral efficiency problem at the cell boundary, deploying fixed relay stations has been actively considered. In this paper, we consider radio resource management policies based on frequency reuse for fixed relays that include path selection rules, frequency reuse pattern matching, and frame transmission pattern matching among cells. We evaluate performance of each policy by varying parameter values such as relay stations position and frequency reuse factor. Through Monte Carlo simulations and mathematical analysis, we suggest some optimal parameter values for each policy and discuss some implementation issues that need to be considered in practical deployment of relay stations. We also surveyed further works that many researchers have been studied to tackle the similar problems of QoS scheduling and resource management for relay with our proposed work. We expect that there would be more future works by priority-based approach and energy-aware approach for QoS scheduling. Also current trends such as the rising interest in IoT system, discussion of densification of cells and D2D communications in 5G systems make us expect that the researches in these topics related with relays would be popular in the future. We also think that there are many interesting problems regarding QoS support and resource management still waiting to be tackled, especially combined with recent key topics in mobile communication systems such as 5G standardization, AI and NFV/SDN.Chapter 1 Introduction 1 1.1 QoS Packet Scheduler 4 1.2 Fixed Relay Frequency Reuse Policies 6 Chapter 2 Scheduler Design for Multiple Traffic Classes in OFDMA Networks 10 2.1 Proposed Schedulers 10 2.1.1 Scheduler Structures 12 2.1.2 MLWDF scheduler for Multiple Traffic Classes 13 2.1.3 Joint Scheduler 13 2.2 System Model 18 2.3 Performance Evaluation 19 2.3.1 Schedulers for Multiple Traffic Classes 20 2.3.2 Impact of Scheduler Selection Rule 25 2.3.3 Frame Based Schedulers 27 2.3.4 Impact of Partial Feedback 30 2.3.5 Adaptive Threshold Version Schedulers 33 2.4 Conclusion 36 Chapter 3 Frequency Reuse Policies for Fixed Relays in Cellular Networks 40 3.1 System Model 40 3.1.1 Frame Transmission and Frequency Reuse Patterns among RSs 42 3.1.2 Positioning of RSs and Channel Capacity 44 3.1.3 Area Spectral Efficiency 45 3.2 Radio Resource Management Policies Based on Frequency Reuse 46 3.2.1 Path Selection Rule 46 3.2.2 Frequency Reuse and Frame Transmission Pattern Matchings among Cells 52 3.3 Monte Carlo Simulation and Results 53 3.4 Consideration of Practical Issues 80 3.5 Conclusion 81 Chapter 4 Surveys of Further Works 83 4.1 Further Works on QoS Schedulers 83 4.1.1 WiMAX Schedulers 85 4.1.2 LTE Schedulers 92 4.2 Further Works on Radio Resource Management in Relay Systems 98 4.3 Future Challenges 100 Chapter 5 Conclusion 104 Bibliography 107 초록 127Docto

A Survey on Scheduling in IEEE 802.16 Mesh Mode

Cataloged from PDF version of article.IEEE 802.16 standard (also known as WiMAX) defines the wireless broadband network technology which aims to solve the so called last mile problem via providing high bandwidth Internet even to the rural areas for which the cable deployment is very costly. The standard mainly focuses on the MAC and PHY layer issues, supporting two transmission modes: PMP (Point-to-Multipoint) and mesh modes. Mesh mode is an optional mode developed as an extension to PMP mode and it has the advantage of having an improving performance as more subscribers are added to the system using multi-hop routes. In 802.16 MAC protocol, mesh mode slot allocation and reservation mechanisms are left open which makes this topic a hot research area. Hence, the focus of this survey will mostly be on the mesh mode, and the proposed scheduling algorithms and performance evaluation methods

Improving relay based cellular networks performance in highly user congested and emergency situations

PhDRelay based cellular networks (RBCNs) are the technologies that incorporate multi-hop communication into traditional cellular networks. A RBCN can potentially support higher data rates, more stable radio coverage and more dynamic services. In reality, RBCNs still suffer from performance degradation in terms of high user congestion, base station failure and overloading in emergency situations. The focus of this thesis is to explore the potential to improve IEEE802.16j supported RBCN performance in user congestion and emergency situations using adjustments to the RF layer (by antenna adjustments or extensions using multi-hop) and cooperative adjustment algorithms, e.g. based on controlling frequency allocation centrally and using distributed approaches. The first part of this thesis designs and validates network reconfiguration algorithms for RBCN, including a cooperative antenna power control algorithm and a heuristic antenna tilting algorithm. The second part of this thesis investigates centralized and distributed dynamic frequency allocation for higher RBCN frequency efficiency, network resilience, and computation simplicity. It is demonstrated that these benefits mitigate user congestion and base station failure problems significantly. Additionally, interweaving coordinated dynamic frequency allocation and antenna tilting is investigated in order to obtain the benefits of both actions. The third part of this thesis incorporates Delay Tolerate Networking (DTN) technology into RBCN to let users self-organize to connect to functional base station through multi-hops supported by other users. Through the use of DTN, RBCN coverage and performance are improved. This thesis explores the augmentation of DTN routing protocols to let more un-covered users connect to base stations and improve network load balancin

C-Band Airport Surface Communications System Standards Development, Phase I

This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." The proposed future C-band (5091- to 5150-MHz) airport surface communication system, referred to as the Aeronautical Mobile Airport Communications System (AeroMACS), is anticipated to increase overall air-to-ground data communications systems capacity by using a new spectrum (i.e., not very high frequency (VHF)). Although some critical services could be supported, AeroMACS will also target noncritical services, such as weather advisory and aeronautical information services as part of an airborne System Wide Information Management (SWIM) program. AeroMACS is to be designed and implemented in a manner that will not disrupt other services operating in the C-band. This report defines the AeroMACS concepts of use, high-level system requirements, and architecture; the performance of supporting system analyses; the development of AeroMACS test and demonstration plans; and the establishment of an operational AeroMACS capability in support of C-band aeronautical data communications standards to be advanced in both international (International Civil Aviation Organization, ICAO) and national (RTCA) forums. This includes the development of system parameter profile recommendations for AeroMACS based on existing Institute of Electrical and Electronics Engineering (IEEE) 802.16e- 2009 standard