WiMAX Service Research Articles

Intra-ONU Bandwidth Allocation Games in Integrated EPON/WiMAX Networks

Integration of Ethernet passive optical network (EPON) and WiMAX technologies is regarded as a promising solution for next-generation broadband access networks. In implementing such networks, efficient bandwidth allocation schemes are essential to satisfy quality of service (QoS) and fairness requirements of various traffic classes. Existing proposals for solving the bandwidth allocation problem in EPON/WiMAX networks neglect interactions between the self-interested EPON and WiMAX service providers (WSPs). Accordingly, this study proposes a two-stage game-theoretic framework for the intra-ONU bandwidth allocation process where the interactions between the EPON and WSPs are taken into account. In the first stage of the proposed framework, a fair and efficient sharing of the available upstream bandwidth between the EPON and WiMAX networks is determined using two market models (i.e., noncooperative and cooperative). In the second stage, the bandwidth allocation obtained from the first stage is distributed among the different traffic classes within the Ethernet and WiMAX networks in accordance with their QoS requirements by means of a Nash bargaining game. Simulation results show that the proposed game-theoretic framework efficiently allocates bandwidth under different market models while simultaneously ensuring proportional fairness among the various traffic classes for the corresponding networks.

Improvement of the QoS for WiMAX Service Classes

Mobile users connected to the WiMAX technology can use five different service classes according to their different needs. In this paper we propose priority based uplink scheduling scheme for IEEE 802.16 standard that improves the QoS performances of the WiMAX service classes, especially when the number of connections gets higher. Essential QoS parameters like throughput, delay and jitter have been calculated using the ns-2 simulation tool and changing the number of the ertPS connections. Obtained results prove that our proposed uplink scheduling algorithm gives better results compared with so far known uplink scheduling mechanism.

MIMO Antenna Using Resonance of Ground Planes for 4G Mobile Application

A MIMO antenna using the resonance of ground planes is proposed for 4G mobile application. A resonant mode is generated when the double ground planes (upper and lower) in the mobile terminal are excited as the radiator. By combining the resonant modes contributed from both the antenna element and the ground planes, the proposed MIMO antenna realizes a wideband property over LTE band 13. In addition, an inductive coil is employed to reduce the antenna volume. These approaches not only simplify antenna design but also effectively improve bandwidth and efficiency. The proposed MIMO antenna has an excellent ECC value of below 0.1 because of the nearly orthogonal radiation patterns of the two radiators. Moreover, an additional antenna is adopted to cover WiMAX, WLAN, and Bluetooth services simultaneously in frequency range from 2 GHz to 2.7 GHz.

Analysis of Radio Interference through Ducting for 2.5 GHz WiMAX Service

Radio interference has been occurring in mobile communication services on the southern seashore in Korea. Monitoring the radio interference signal revealed that the main reason for the radio interference was a radio ducting signal coming from the seaside of Japan. In this paper, we have analyzed the effect of interference on WiMAX service using a 2.5 ㎓ frequency band between Korea and Japan. We focus on the interference scenario from base station to base station and we use the Minimum Coupling Loss (MCL) method for interference analysis and the Advanced Propagation Model (APM) for calculating the propagation loss in ducts. The propagation model is also compared with experimental measurement data. We confirm that the interfering signal strength depends on the antenna height and this result can be applied to deployment planning for each system with an interference impact acceptable to both parties.

Practical service level agreement negotiation scheme for multicast service in WiMAX

For multicast service in WiMAX, there are trade-offs between overall channel efficiency and the number of users under the commitment of service level agreements (SLAs). So, it is important to compromise between accommodating many users under the commitment of SLA and channel efficiency. In order to give an insight of multicast efficiency, we suggest a novel metric which is named as channel efficiency (MCE) factor. In addition, we proposed the practical SLA negotiation scheme based on proposed novel metric. Numerical results show that the proposed practical scheme significantly outperforms the conventional multicast transmission scheme.

Channel Encoding Block for Mobile WiMAX Networks Using Reconfigurable Hardware

WiMAX technology aims to provide wireless metropolitan area transmissions with guaranteed quality of service. Towards this aim, sophisticated channel encoding techniques must be implemented in a hardware, which is optimized for such techniques. In this context, this article presents the design of a channel encoder for mobile WiMAX networks, which is prototyped in reconfigurable hardware architecture.The validation of the prototype was conducted considering scheduled traffic in the medium access control layer. Results showed that the channel encoder is fundamental for guaranteeing quality of service in mobile WiMAX networks.Keywords: Channel Encoding Block, Reconfigurable Hardware, WiMAX.

Experimental Demonstration of Multi-Service Hybrid Fiber-Radio System Using Digitized RF-Over-Fiber Technique

An efficient multi-channel hybrid fiber-radio scheme for both down and up-link paths is demonstrated based on digitized RF-over-fiber technique, where the frequency translation stages are implemented using a single analog-to-digital converter (ADC) and digital-to-analog converter (DAC) instead of mixers and local oscillators. The simultaneous transmission of GSM, UMTS and WiMAX services is demonstrated with error-free reception. With a minimum sampling rate of 50 MHz and an overall optical data rate of 400 Mb/s, all the three wireless services can be successfully recovered in a full-duplex transmission. In the downlink direction, the performance is dependent on the amount of amplification required for the wireless signal at the desired carrier frequency. The amount of amplification on the other hand is dependent on the location of the wireless signal within the Nyquist zone which increases significantly with the order of the Nyquist zone. In the uplink direction, the performance is limited by inter-channel interference as a result of spectra aliasing of the regenerated IF signals which limits the signal-to-noise-ratio. With proper system design that optimizes downlink amplification and minimizes inter-channel interference, simultaneous multi-service transmission using digitized RF-over-fiber technique is able to improve spectral efficiency and minimize hardware count.

Wibro/WLAN/Mobile WiMAX용 소형 광대역 안테나

본 논문에서는 이동 통신 단말기에 적합한 소형 광대역 안테나를 제안한다. 제안된 안테나는 프린트된 사각형 모노폴 형태와 그라운드 면에 얇은 미앤더 선로로 연결된 기생 소자로 구성되며, 실제 단말기 환경에 맞춰서 45 mm<TEX>${\times}$</TEX>90 mm 크기를 갖는 두께 0.8 mm이고, 유전율 4.4인 FR-4 기판을 이용하여 시스템 기판을 이용하여 설계하였다. 실제 제작한 안테나의 크기는 10.5 mm<TEX>${\times}$</TEX>12.5 mm<TEX>${\times}$</TEX>0.8 mm이며, 반사 손실 -10 dB 대역폭은 2,200~6,000 MHz, 이득은 2.86~4.01 dBi을 가짐을 측정을 통해 확인하였다. 따라서 제안된 안테나는 국내 WiBro 서비스 대역(2,300~2,380 MHz)과 WLAN 대역(IEEE 802.11b/g/n: 2,400~2,480 MHz, IEEE 802.11a: 5,150~5,825 MHz) 그리고 국외 mobile WiMAX 대역(IEEE 802.16e: 2,500~2,690 MHz, 3,400~3,600 MHz)을 지원하는 단말기 안테나로 적합하다. In this paper, we propose a small broadband antenna for mobile device. The proposed antenna consists of a printed rectangular monopole antenna and a parastic element connected to ground using narrow meander line and it is designed on a FR-4 substrate that has a thickness of 0.8 mm and a dielectric constant of 4.4. The FR-4 substrate's size is 50 mm<TEX>${\times}$</TEX>90 mm comparable to the real mobile device. The fabricated antenna's size is 12.5 mm<TEX>${\times}$</TEX>10.5 mm<TEX>${\times}$</TEX>0.8 mm and the measurement shows -10 dB return loss bandwidth of 2,200~6,000 MHz and gains of 2.86~4.01 dBi. Accordingly, the proposed antenna can support mobile device for WiBro(2,300~2,380 MHz), WLAN(IEEE 802.11b/g/n: 2,400~2,480 MHz, IEEE 802.11a: 5,150~5,825 MHz), and mobile WiMAX(IEEE 802.16e : 2,500~2,690 MHz, 3,400~3,600 MHz) service bands.

A COMPACT UWB ANTENNA WITH DUAL BAND REJECTION

In this communication, a new compact UWB monopole antenna with dual band rejection is presented. The antenna is designed using FR4 substrate with dielectric constant 4.4, loss tangent 0.02 and a height of 1.59mm. Initially the UWB antenna is designed to obtain a 153% fractional bandwidth from 2.4GHz{21.7GHz. The ground plane beneath the patch is etched out and a rectangular slot is introduced to obtain a broadband matching over the operating frequency range. Later the antenna is modifled to get a frequency notch in the IEEE802.11a and HIPERLAN/2 WLAN operating band (5.15GHz{5.825GHz) to avoid potential interference. A U shaped slot is optimally introduced in the patch to get the desired performance. Finally an L shaped slot is cut from the radiating patch to fllter the frequency band 3.3GHz{3.6GHz, which is WiMAX service band. The antenna parameters are optimized and the efiects of parametric variation on antennas performance are studied and the summary is presented. The antenna is fabricated and measured results are presented. The measured results are in well agreement with the simulated results.

A Cross-Layer Approach to Fair Resource Allocation for Multimedia Service in WiMAX

In this paper, a cross-layer resource allocation mechanism is proposed for wireless multimedia service. In particular, a game theory based on quality of service (QoS) for multimedia users is introduced to deal with the fairness of network resource allocation in wireless networks. Moreover, the channel states of wireless users are additionally regarded under the cross-layer design in WiMAX environment. In details, the bargaining solution is adopted to discover the efficient and fair resource allocation strategy for multimedia service in considering QoS in the peak signal-to-noise ratio (PSNR) and the channel states in the carrier-to-interface ratio (CINR). The proposed mechanism is illustrated and evaluated by simulation results of transmitting video sequences in WiMAX environment.

A concurrent triple-band CMOS low noise amplifier for fourth generation applications

In this study, a concurrent triple-band low noise amplifier (LNA) is designed for long term evolution (LTE), Mobile-WiMAX (M-WiMAX), and WiMAX services. The main topology of the proposed LNA is a cascode architecture with source degeneration using shunt resistive feedback topology for the triple-resonance characteristic. The LNA is designed using a Taiwan Semiconduction Company (TSMC) 0.18 μm radio frequency CMOS process. To obtain the necessary gains over the operating frequency bands, a series LC branch is added in parallel with an inductor at the drain load of a single band LNA. The peak gains at LTE, M-WiMAX, and WiMAX bands are 17.6, 14.7, and 14.5 dB, respectively, whereas dissipating 8 mA from a 1.4 V supply voltage. The average noise figure over the three operating frequency bands is 4.5 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:415–418, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25743

무선 USB 동글 장치를 위한 프린트형 미앤더 모노폴 안테나

In this paper, a novel printed meander monopole antenna is proposed for wireless USB dongle applications. Dual-wideband resonance is obtained by utilizing a printed meander monopole radiator. The proposed antenna was fabricated on a thin FR-4 substrate with a thickness of 1 mm and a dielectric constant of 4.6. The antenna is fed by a coaxial cable. This novel USB dongle antenna measures only . The measured results demonstrates that the antenna supports WiBro, Bluetooth/ISM, WLAN, S-DMB, and WiMAX service bands.

Novel Shorted Meander-Line USB Dongle Antenna with a Compact Ground Plane

This letter presents the design of a novel multiband USB dongle antenna with a compact ground plane. The radiating patch is composed of a modified meander-line monopole and a shorted loop to generate a dual-broadband resonance. The proposed antenna supports WiBro, Bluetooth, WLAN, WiMAX, and S-DMB services. The total dimensions of the fabricated antenna are 10 mm × 45 mm × 1 mm, the most compact size among multiband USB dongle antennas reported to date. The measured 10 dB reflection loss bandwidths are 20.8% (2.24 GHz to 2.76 GHz) and 20.2% (4.86 GHz to 5.95 GHz). The measured peak gain is 2.97 dBi, and efficiency is higher than 58%. In addition, the radiation pattern approximates an omnidirectional pattern.

Compact stub-loaded meander-line antenna for wireless USB dongle devices

A planar meander-line monopole antenna was designed for wireless Universal Serial Bus (USB) dongle devices. The proposed antenna shows dual-wideband resonant characteristics and supports the WiBro, Bluetooth, WLAN, WiMAX, and S-DMB (Satellite Digital Multimedia Broadcast) services. The designed antenna measures 19 × 50 × 1 mm3, which is suitable for compact USB dongles. The measured 2:1 bandwidths of the voltage standing wave ratio are 18.1% (2.26–2.71 GHz) and 16.4% (5.09–6.0 GHz). The measured peak gain is 3.49 dBi, and efficiency is higher than 56%. The radiation patterns are also nearly omni-directional. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2279–2282, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25430

Adaptive Cost-Based with Max–Min AMC Routing Algorithm for Increasing Utilization and Reducing Blocking in IEEE 802.16j WiMAX Networks

Based on the IEEE 802.16e standard, WiMAX has proposed a relay-based mechanism, namely IEEE 802.16j, to extend the service area of the Multihop Relay Base Stations (MR-BSs) and to improve the Received Signal Strength quality. IEEE 802.16j thus can achieve two significant advantages: extending the WiMAX service area with a low-cost solution and compatible with the existing WiMAX specifications. The Relay Station (RS) can be classified into three types: Fixed RS, Nomadic RS and Mobile RS according to diverse features of mobility and relaying range. A multihop-relay WiMAX network including various types of RSs exhibits a critical routing issue, i.e., how to determine an efficient relay-based routing path between a Mobile Station (MS) and a MR-BS. This paper thus proposes an IEEE 802.16j-conformed relay-based adaptive competitive on-line routing approach that focuses on the Non-Transparent Relay-Station (NT-RS) mode, where the path with the least cost and the highest AMC coding rate will be selected in terms of the link bandwidth, path length and channel conditions. Numerical results indicate that the proposed routing approach significantly outperforms other approaches in Fractional Reward Loss, network utilization and average end-to-end path delay.

Hierarchical scheduling framework for QoS service in WiMAX point-to-multi-point networks

Quality of service (QoS) is an important issue in the deployment of broadband wireless access networks with real-time and non-real-time traffic integration. In this study, the authors propose a three-tier QoS service architecture and scheduling schemes to provide QoS supports in WiMAX networks with point-to-multi-point (PMP) topology. The distinct feature of the proposal is that QoS provisioning has been dynamically distributed to three tiers and implemented independently by both base station (BS) and subscriber stations (SSs). The performance of the proposed solution has been evaluated by extensive simulations and the theoretical analysis. The evaluation results show that our proposal can improve the performance of WiMAX PMP network much in terms of packet delay, packet loss rate and throughput.

Quality of service in WiMAX and LTE networks [Topics in Wireless Communications

A quality of service framework is a fundamental component of a 4G broadband wireless network for satisfactory service delivery of evolving Internet applications to end users, and managing the network resources. Today's popular mobile Internet applications, such as voice, gaming, streaming, and social networking services, have diverse traffic characteristics and, consequently, different QoS requirements. A rather flexible QoS framework is highly desirable to be future-proof to deliver the incumbent as well as emerging mobile Internet applications. This article highlights QoS frameworks and features of OFDMA-based 4G technologies - IEEE 802.16e, IEEE 802.16m, and LTE - to support various applications' QoS requirements. A few advanced QoS features such as new scheduling service (i.e., aGP), quick access, delayed bandwidth request, and priority controlled access in IEEE 802.16m are explained in detail. A brief comparison of the QoS framework of the aforementioned technologies is also provided.

Converged delivery of WiMAX and wireline services over an extended reach passive optical access network

In this paper we present long-reach fiber access links supporting transmission of Worldwide Interoperability for Microwave Access (WiMAX) compliant signals. We present bi-directional full-duplex transmission of 256-state quadrature amplitude modulation (256-QAM) modulated WiMAX-compliant signals on a 2.4-GHz RF carrier over an 80-km long-reach access link at 100 Mb/s (down) and 64 Mb/s (up). Transmission of 64-QAM and 256-QAM-modulated signals on a 5.8-GHz RF carrier over a 118.8-km access link converged with four baseband differential quadrature phase shift keying (DQPSK) modulated wireline channels, along with ultra-wide band (UWB) and phase shift keying (PSK) radio-over-fiber (RoF) wireless signals over a deployed optical fiber link is also presented.

Circular hook-shaped wireless USB dongle antenna with an open stub

This research presents the design of a novel pentaband planar antenna for wireless USB dongle applications. The main radiator is comprised of a circular hook-shaped patch and a monopole stub to achieve dual-wideband operation. This novel pentaband antenna measures only 10 × 49.5 × 0.8 mm3. The measured 10dB return loss bandwidths of the fabricated antenna are 26.2% (2.29-2.98GHz) and 21.5% (5.12-6.35GHz), thereby supporting WiBro, Bluetooth, WLAN, WiMAX, and S-DMB (Satellite Digital Multimedia Broadcast) services. The gain and radiation efficiency of the antenna are also discussed.

Design and implementation of tiny-WiMAX connection manager (t-WCM) for specific purposed devices

WiMAX network services cannot generally be provided for special purpose devices such as credit card systems and surveillance systems since they are designed to operate only with WCM which should be installed on personal computer/smart card (PC/SC) with Windows platform. In this paper, we propose a design and implementation technique called tiny-WiMAX connection manager (t-WCM) for non-PC/SC WCM to provide WiMAX services to special purpose devices. The t-WCM is composed mainly of three units; WiMAX module control unit (WCU), data surveillance unit (DSU), and external device program unit (EPU). It also has TCP/IP protocol stack and RTOS kernel, and performs data transmission between external end user's device and remote server system over WiMAX networks. For the performance evaluation of the proposed t-WCM, we have implemented the t-WCM and tested it under a commercial mobile WiMAX network environment. From the experimental results, the t-WCM is verified to show almost equal stability and delay performances with the legacy WCM and xDSL, and especially better than 1xEV-DO. As a result, it has a strong possibility to apply the t-WCM to many types of special purpose embedded systems, and consequently to provide various WiMAX network services to them.