WiMAX Networks Research Articles

Multi-Hop WiMAX Networks: A New Opportunistic Algorithm Using AMC and PUSC Mode for Different Mobility Users

Resource allocation algorithms play the main role in provisioning high throughput in broad band wireless communications. The previous studies in WiMAX networks have considered either AMC or PUSC techniques for the resource allocation algorithms. In this way, AMC based algorithms have presented high throughput for low speed users. Conversely, PUSC based algorithms have not been affected by users' speed, whilst the throughput is low. To date, the importance of presenting proportional fair and maintaining the network throughput for the users with different speeds has not been acknowledged yet. This paper presents a novel opportunistic algorithm which is suitable for the users with different mobility speeds. The new algorithm uses two modes of AMC and PUSC simultaneously. The simulation results reveal that in comparison to similar algorithms, the proposed algorithm presents more proportional fair throughput when there are both high and low speed users.

A CROSS-LAYERED PATH STABILITY BASED ROUTING PROTOCOL FOR WiMAX NETWORKS

In IEEE 802.16, a Subscriber Station (SS) is batter y powered with limited capacity. A SS can be made to operate for longer durations by deploying power sav ing features or by using relay stations. Multi-hop communication conserves power, but finding an optimal path to the destination is monotonous. Path stability indicates how stable a path is and how lo ng it can support communication. Identifying stable paths helps in reducing the control traffic, number of co nnection disruptions and also in conserving power. In this study, Greedy Perimeter Stateless Routing (GPSR) and Link-St Ability and Energy aware Routing (LAER) designed for Mobile Ad hoc NET works (MANETs) are implemented for WiMAX networks and their performance is evaluated. Further, a novel Cross-la yered Path Stability based Routing protocol (CPSR) is proposed to find a stable path based on Residual En ergy (RE), Received Signal Strength Indicator (RSSI) and Signal-to-Noise Ratio (SNR). The total energy consumed is minimized, thus maximizing the network lifetime.

Performance analysis of non-PC/SC based mini-WiMAX connection manager

In order to provide WiMAX network services to specific purposed devices such as credit card systems and surveillance systems, we have proposed a new non-PC/SC based mini WiMAX Connection Manager (non-PC/SC m-WCM) that can be applied to small hardware system or architecture with Micro Controller Unit (MCU). The existing legacy WiMAX Connection Managers (WCMs) generally run on the operating systems such as Windows and Linux. This makes it hard to design and implement lightweight WCMs for the specific purposed devices that have very limited hardware capabilities. In order to solve the problem, we propose a new non-PC/SC m-WCM architecture which has almost same functionalities of the legacy WCM and implement non-PC/SC m-WCM without the performance degradations. The proposed non-PC/SC m-WCM mainly consists of three units; WiMAX module Control Unit (WCU), Data Surveillance Unit (DSU), and External device Program Unit (EPU). Besides these, it also has TCP/IP protocol stack and RTOS kernel, and can transmit date between external end user's device and remote server system over the WiMAX networks. For the delay and throughput performance comparisons with the legacy WCMs, we have implemented the non-PC/SC m-WCM and tested it under a commercial mobile WiMAX network environment. From the experimental results, the non-PC/SC m-WCM is verified to show almost equal stability and delay performances with the legacy WCM and xDSL, but especially better than WCDMA. In the throughput tests, it has been shown that each of the modems shows almost similar throughput performance. Although the proposed WCM is designed with the very limited hardware specifications, it shows no performance degradations compared to the legacy WCMs. As a result, it has a strong possibility to be able to apply the non-PC/SC m-WCM to various types of specific purposed embedded systems, and to provide them with the same levels of WiMAX network services as those provided by the legacy WCMs.

Distributed Agent-based IP Location System Framework Design

Computer crime causes significant impact and 
 losses to society and the public security of countries, and 
 even influences homeland security. From previous lessons, 
 we know that the physical location of computer criminals 
 plays an important role in combat with computer crime, 
 including IP Traceback and IP Location. Literature review 
 shows that there have been many studies of the topic of IP 
 Traceback. However, the most critical IP Location has not 
 yet been thoroughly discussed, and existing IP Location 
 approaches, as based on end-to-end delay measurement 
 from a set of landmarks, fail to outperform much simpler 
 techniques, and the error of these approaches is strongly 
 determined by the distance to the nearest landmark, even 
 when triangulation is used to combine estimates from 
 different landmarks. In view of this, this study uses the 
 concept of IP Location and Network Forensics to propose 
 the distributed agent-based IP Location system framework 
 in order that the "position" of the criminal can be traced, 
 and identity can be deduced by this mechanism, when 
 cybercriminal behavior occurs. The result of actual 
 implementation in WiMAX networks shows that the 
 accuracy of IP Location can be the coverage area of a base 
 station (in radius of 150-500 m in urban areas).

A Survey and Analysis on Scheduling Algorithms in IEEE 802. 16e (WiMAX) Standard

Man or WiMAX, where WiMAX stands on Worldwide Interoperability for Microwave Access, is one of the latest technologies in the Wire-Less World. The main goal of WiMAX is to deliver wireless communications with quality of service in a secured environment. Unlike wireless LANs, WiMAX networks incorporate several qualities of service (QoS) mechanisms at the Media Access Control (MAC) level for guaranteed services for data, voice and video. Its Mobility feature makes it different from the other IEEE 802.16 protocols which was based on Static WiMAX and provided the Wireless communication at fixed locations. This paper deals with the key features of the IEEE 802.16e scheduling algorithms at MAC layer, their classification and their survey in which several authors have already done the research in this field. In addition to ensuring feasible algorithm complexity and system scalability, the purpose of scheduling algorithms also includes optimal usage of resources, to assure what the QoS guarantees, to maximize good throughput and to minimize power consumption.

WiMAX Network for Capacity and Coverage Assessment

This article represents the system performance and its operation stability of a fixed worldwide interoperability for microwave access network operating with point to multipoint technology. It provides broadband access in fixed locations for mixed environments in Greater Noida, UP, India. The Field measurement for its capacity and coverage are recorded simultaneously to optimize a network by raising customer premises equipment (CPE) antenna height. This process is not going to alter any technical parameters of a network. CPE antenna is a directional antenna facing towards base station to achieve optimum LOS reception. The net changes in RSS 10---17 dBm, DTR 512---1.8 Mbps, path loss exponent 0.5---0.9 and standard deviation of 1.2---2.3 were observed by raising CPE antenna height of 2---5 m above the prescribed height. The path loss exponents for different environments are obtained using least squares method based on measured data by MatLab statistics tool. Standard deviations of signal strength variability with distance are derived. Real coverage of a network is presented based upon path loss exponent and standard deviation. Our result suggest that, raising the height of CPE antenna can reduce transmitted power, there for reducing overall maintenance cost and system interference in future.

An IMS-based integration architecture for WiMax/LTE handover

To enable seamless handovers for broadband networks, many researchers have addressed the integration of heterogeneous access technologies to provide users with always-on connectivity. Currently, there are several researches reported in the literature that discuss the integration of beyond 3G networks such as 3GPP Long Term Evolution LTE and mobile WiMax networks. They mainly focused on providing mobile users with seamless mobility when switching between heterogeneous access networks. In this context, many solutions for integration architecture have been proposed with mobility management considerations such as loose and tight coupling, IP Multimedia Subsystem IMS-based architecture and Evolved Packet Core EPC-based solutions for the purpose of providing mobile users with seamless handovers. In this paper, we present the different integration solutions and propose an integration architecture for WiMax and LTE access technologies with EPC as core network and IMS for service provisioning. A vertical handover VHO scheme is presented based on cross-layer approach that enables vertical handover with less handover latency and signaling cost.

Measurement and analysis of online gaming services on mobile WiMAX networks

Online games have been played mainly in desktop computers over wired networks because of high speed and intensive computation requirements. The advances in mobile devices and ever increasing wireless link bandwidth motivate us to study whether players can enjoy online gaming over broadband wireless networks such as mobile Worldwide Inter-operability for Microwave Access WiMAX. In this paper, we carry out comprehensive measurements of the World of Warcraft WoW over the mobile WiMAX in Seoul, Korea, and analyze the network performance focusing on two aspects: 1 network layer dynamics such as round trip time, jitter, and packet loss and 2 WiMAX link layer statistics such as the radio signal strength, handovers, and piggyback mechanism. From the empirical data, we set up performance models and evaluate the performance of WoW over WiMAX. We also discuss how to improve the service quality of online gaming over WiMAX.Copyright © 2013 John Wiley & Sons, Ltd.

Optimized network dimensioning and planning for WiMAX technology

In order to meet demands in mobile broadband and to bridge the digital divide WiMAX was introduced in 2004. However, in order to increase the financial return on the investment, service operators need to make every effort in designing and deploying the most cost-effective networks using this technology. This paper presents a novel dimensioning technique for WiMAX technology which takes the dimensioning problem to a new level and produces more accurate results in comparison to traditional methods. Furthermore, a novel decomposed optimization framework for the WiMAX network planning is introduced which subdivides the overall problem into three distinct stages – a network dimensioning stage, initial sectorization and configuration stage and a final network configuration stage. The proposed framework also solves two fundamental problems, which are cell planning and frequency planning, simultaneously. Optimization is based on a tailored simulated annealing algorithm. Results, based on experiments in and around a UK city, show that the three stage framework produces viable designs with good coverage and service. In particular Stage 1 is efficient and more accurately dimensions the network than the traditional methods.

Wireless Fair Intelligent Congestion Control — A QoS Performance Evaluation

In Broadband Wireless Access (BWA) networks, provisioning of Quality of Service (QoS) is absolutely essential for real time and non real time services. Congestion in these networks can lead to deterioration in QoS experienced by the network users. Congestion avoidance is rarely considered to ensure the QoS of wireless connections. Efforts are mainly aimed at reducing the overload once it has occurred. To avoid congestion at the base station in WiMAX networks, the WiMAX Fair Intelligent Congestion Control (WFICC) was proposed to ensure the traffic is scheduled in such a way that the base station output buffer operates around a target operating point without violating the QoS requirements of connections. The aim of this paper is to investigate WFICC thoroughly and evaluate its performance in terms of throughput, delay and jitter for different Classes of Services (CoSs) under various parameter settings of the algorithm. A detailed and comprehensive simulation study on various settings of parameters is performed in ns-2. The results show that WFICC performs excellently in allocating resources fairly among Class of Services (CoSs) and also preserves their QoS requirements. Furthermore, WFICC is robust and easily adapted to various traffic conditions.

Foreword to Special Issue

Parallel and distributed computing has been under many years of development, having played a central role in shaping different research and application trends such as grid computing, cloud computing, green computing, etc. The broad applications of parallel and distributed computing have also made the relevant research field interdisciplinary, cross boundaries among architectures, communications, computing, algorithms and programming. The objective of this special issue is to address some recent developments in this interdisciplinary area. The special issue is based on the presentations made at the 13th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT 2012) held in Beijing, 14–16 December 2012. Fatima Furqan and Doan B. Hoang in their paper “Wireless Fair Intelligent Congestion Control — A Qos Performance Evaluation” propose a congestion control scheme in WiMAX Networks, by scheduling the traffic and ensuring the output buffer of base station operates around a target operating point without violating the QoS requirement of connections. The paper evaluates the performance of the proposed scheme in terms of throughput, delay and jitter for different classes of services under various parameter settings. A detailed simulation study on various settings of parameters is also carried out in NS-2. Yangyang Li, Hongbo Wang, Jiankang Dong, Junbo Li and Shiduan Cheng in their paper “Differentiated Bandwidth Guarantees for Cloud Data Centers” propose a differentiated bandwidth allocation scheme for data center networks, to guarantee network performance of applications and provide fine-grained service differentiation. The problem is formulated as a multi-objective optimization problem and solved by a heuristic algorithm. Xu Liang, Youli Qu and Guixiang Ma in their paper “Research on Contrastive Viewpoint Summarization for Opinionated Texts” propose an approach for summarizing multi-topic contrastive viewpoints in opinionated text processing. They model the opinionated texts with Topic-Aspect Model and get the topic and aspect attribute of each sentence, and use some ranking methods to evaluate the centrality of each sentence, based on which the summary is finally generated. We sincerely thank all the authors and reviewers for their contributions to this special issue. Special thanks are given to Prof. Francis Lau, the EIC of JOIN, for

Measures to quantify the gain of multicast with application to IPTV transmissions via WiMAX networks

In applications like IPTV, multicasting provides beneficial services. However, due to overhead and problems of multicast transmission, multicasting is not always profitable. In order to make well-justified decisions whether it is worthwhile to use multicasting or not, its efficiency must be quantified. Therefore, the metric of `multicast gain' is introduced as a measure for the bandwidth reduction which can be expected when using multicast (instead of multiple unicast). Different definitions for multicast gain are given to cover different types of links. As an application of our metric, multicast transmission of live TV channels in WiMAX-based access networks is analyzed. WiMAX as one of the 4G candidates can transmit IPTV services to mobile subscribers because of salient features such as multicast support, wide coverage range and high bandwidth. In OFDMA-based WiMAX the smallest logical bandwidth allocation unit is a slot. In this article, we use the term slot to measure the efficiency of multicasting in WiMAX networks. We show that for unpopular TV channels, using unicast flows can be preferable.

A new CAC and packet scheduling scheme for mobile WiMAX networks

ABSTRACTAs the wireless network technology evolves, IEEE 802.16 standard, also known WiMAX (Worldwide Interoperability for Microwave Access) appears as a great competitor to GSM, 3G, even IEEE802.11 networks. The coverage of this technology is expanded up to 50 km. It is claimed to provide a transmission rate up to 70 Mbps while respecting the QoS (Quality of Service) mechanism. However, the call admission control (CAC), scheduling and bandwidth allocation mechanisms were not defined and left as an open issue. In this paper, we introduce a CAC scheme and a scheduling algorithm for IEEE802.16e Mobile WIMAX. An efficient token bucket based CAC and uplink packet scheduling scheme is introduced in order to satisfy bandwidth guarantees to all service flow and delay guarantees to real time service flows. The proposed solution is practical and compatible to the IEEE 802.16 standard as it provides the QoS of different traffic classes especially best effort traffic by avoiding its starvation as is specified in major previous works. An analytical model and simulation results are developed in order to validate the proposed CAC scheme and the scheduling algorithm. By numerical results, we show that our proposed scheme is compatible to the IEEE 802.16 standard as it performs significantly the best effort traffic without violating QoS performance of other service classes.Copyright © 2013 John Wiley & Sons, Ltd.

Efficiency-driven selection of bandwidth request mechanism in broadband wireless access networks

To avoid collisions in WiMAX networks, the connections in Subscriber Stations (SSs) use a request–grant process to acquire transmission resources from the Base Station (BS). In accordance with the IEEE 802.16 standard, the request–grant process is accomplished using either a unicast polling method or a contention request method. In WiMAX systems, the number of bandwidth-request (BR) slots per frame is limited. Thus, to enhance the network performance, the BR slots must be used in the most efficient manner possible. In practical WiMAX systems, the offered network load varies over time, and thus the strict use of either the unicast polling method or the contention request method results in a poor utilization efficiency of the BR slots. Accordingly, the present study proposes a scheme designated as Efficiency-Driven Selection of Bandwidth Request (EDSBR), in which the request–grant mechanism is adjusted dynamically on a frame-by-frame basis in accordance with the network conditions. The performance of the proposed scheme is evaluated by simulations. The results show that EDSBR achieves a more efficient utilization of the BR slots than the unicast polling scheme or the contention request scheme, and therefore yields an improved network performance.

Energy-aware QoS uplink scheduling for UGS traffic flows in WiMAX networks

This paper presents a new energy-aware QoS scheduling and call admission control algorithm for WiMAX IEEE 802.16e wireless access standard. The scheduling algorithm works at MAC layer and is designed towards minimizing power consumption at mobile stations supporting multiple Unsolicited Grant Service (UGS) connections, while meeting the QoS requirements of the connections. The algorithm uses a novel idea to fill an active OFDM frame as much as possible in order to increase the number of OFDM frames in sleep mode at mobile station. The algorithm also considers the dynamic nature of connection joining and termination. We used Voice-over-IP (VoIP) traffic connection models for UGS traffic flows to simulate and validate algorithm. The simulation model was tested using VoIP codec types with different rates and QoS requirements. Simulation results show that a power saving in the range of 50–75% can be easily achieved at the mobile station under low-to-moderate traffic intensities.

Concurrent Scanning for High Quality Hand Over Support in Mobile WiMAX Networks

Mobile WiMAX is IEEE 802.16e standard established for mobile broadband wireless access (BWA). Mobility in WiMAX system is an important issue when the mobile station (MS) moves and be handover between base stations (BSs). This issue causes an unnecessary neighboring BS scanning and association, handover delay, and MAC overhead which may affect real-time applications.
 The MS movement direction prediction (MMDP) based MS scanning is used to reduce the number of scanning’s required in mobile WiMAX handover process. In this paper with reduction in number of scanning’s we propose to reduce the scanning delay required for evaluated two best target BSs by using concurrent scanning process. Network issues like ideal sectors in WiMAX 2 (IEEE 802.16m), network congestion and fast change in RSS are important parameters which can affect the QoS. With this proposed model we are able to provide the high quality hand over support in mobile WiMAX wherein we are able to solve the above stated network problems. Here on using the concurrent scanning process the authors are able to reduce the scanning delay by 40%. As a part of this paper, network layer parameters called routing protocols are analyzed for hand over support. This analysis shows an efficient routing protocol for real time application and the best effort service. This reviles that fisheye protocol is better to use for smaller network and LANMAR for the larger networks in real time application and IERP protocol is good for best effort services.

A Survey on Modulation Schemes Used for Link Adaptation in WiMAX Networks

Interoperability for Microwave Access (WiMAX) is a telecommunications technology that uses radio spectrum to transmit bandwidth between digital devices. WiMAX has the ability to transmit large amount of data to large distance. The IEEE standard for WiMAX defines an adaptive modulation framework which allows a WiMAX system to communicate with various burst profiles according to the link quality. This adaptive modulation framework is also called as link adaptation. This link adaptation scheme uses different modulation schemes for different communication link quality. This paper analysis different modulations schemes used in WiMAX link adaptation. Keywordslink adaptation, QPSK, 16QAM, 64QAM, BPSK

Navigation-based self-optimization handover mechanism for mobile relay stations in WiMAX networks

Organic Computing has similar characteristics of organism which can be self-adjustment for a variety of conditions. Moreover, during the wireless communication technological evolution progress, WiMAX (Worldwide Interoperability for Microwave Access) offers ability of high capacity and far distance transmission. WiMAX provides high-speed access and a coverage range across several kilometers, but the actual coverage range was merely a few kilometers due to the shelter of buildings or terrain. IEEE 802.16 working group designed 802.16j-based RS (Relay Station) to overcome above problem. In this paper, we present a mechanism called Self-Optimization Handover Mechanism. This mechanism is using GPS (Global Positioning System) navigation system to gather the related information for the position and combine the mobility characteristics of Mobile Relay Station. Especially, the concept of Self-Optimization of Organic Computing has been integrated into this mechanism. There are some advantages for this new mechanism, including: (1) The base station can provide advance plan and select the path. (2) The mechanism can reduce the number of possible handover and hop. (3) The mechanism can reduce the time of channel scan.

An Enhanced Feedback-Base Downlink Packet Scheduling Algorithm for Mobile TV in WIMAX Networks

With high speed access network technology like WIMAX, there is the need for efficient management of r adio resources where the throughput and Q os requirements for Multicasting Broadcasting Services (MBS) for example TV are to be met. An enhanced feedback-base downlink Packet scheduling algorithm that can be used in IEEE 802.16d/e networks for mobile TV “one way traffic”(MBS) is needed to support many users utilizing multiuser diversity of the broadband of WIMAX systems where a group of users(good/worst channels) share allocated resources (bandwidth). This paper proposes a WIMAX framework feedback-base (like a channel-awareness) downlink packet scheduling algorithm for Mobile TV traffics in IEEE806.16, in which network Physical Timing Slots (PSs) resource blocks are allocated in a dynamic way to mobile TV subscribers based on the Channel State information (CSI) feedback, and then considering users with worst channels with the aim of improving system throughput while system coverage is being guaranteed. The algorithm was examined by changing the PSs bandwidth allocation of the users and different number of users of a cell. Simulation results show our proposed algorithm performed better than other algorithms (blind algorithms) in terms of improvement in system throughput performance. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Doi : 10.12777/ijse.5.1.55-62 [ How to cite this article : Oyewale , J. and , Juan , L.X. . (2013). An Enhanced Feedback-Base Downlink Packet Scheduling Algorithm for Mobile TV in WIMAX Networks . International Journal of Science and Engineering , 5(1),55-62. Doi: 10.12777/ijse.5.1.55-62 ]

Radio Planning and Field Trial Measurement of a Deployed 4G WiMAX Network in an Urban Sub-Saharan African Environment

Worldwide Interoperability for Microwave Access (WiMAX) technology has gained growing interest due to its applications and advantages. It is fast emerging as a last-mile problem solution for broadband access technology. This paper presents operation scenarios for the deployment of a Fourth Generation (4G) WiMAX system in a typical sub-Saharan African environment. This has been specified based on real world conditions considering the regulatory rules specified by the National Communication Authority (NCA) for radio frequency spectrum utilization in the 2.6GHz licensed band in Ghana. Appropriate propagation models and Network planning tools have been used to design the final radio network plan. Coverage prediction has been performed using Genex-U-Net to achieve the main aim of providing coverage in the predefined areas of Accra and Tema, Ghana. Simulation results for different downlink/uplink ratios with different frequency reuse schemes have been presented. A total of 11 base stations have been suggested to provide coverage of -92dBm using 32 sectors 4 transmit 4 receive (4T4R) adaptive Multi-Input Multi-Output (MIMO) antenna configuration within the Accra and Tema municipality. Finally the system performance is evaluated through field trial measurement and the results presented.