WiMAX Base Station Research Articles

Self-Powered Wide Area Infrastructure Based on WiMAX for Real Time Applications of Smart Grid

This work presents a wireless communication network (WCN) infrastructure for the smart grid based on the technology of Worldwide Interoperability for Microwave Access (WiMAX) to address the main real-time applications of the smart grid such as Wide Area Monitoring and Control (WAMC), video surveillance, and distributed energy resources (DER) to provide low cost, flexibility, and expansion. Such wireless networks suffer from two significant impairments. On one hand, the data of real-time applications should deliver to the control center under robust conditions in terms of reliability and latency where the packet loss is increased with the increment of the number of industrial clients and transmission frequency rate under the limited capacity of WiMAX base station (BS). This research suggests wireless edge computing using WiMAX servers to address reliability and availability. On the other hand, BSs and servers consume affected energy from the power grid. Therefore, the suggested WCN is enhanced by green self-powered based on solar energy to compensate for the expected consumption of energy. The model of the system is built using an analytical approach and OPNET modeler. The results indicated that the suggested WCN based on green WiMAX BS and green edge computing can handle the latency and data reliability of the smart grid applications successfully and with a self-powered supply. For instance, WCN offered latency below 20 msec and received data reliability up to 99.99% in the case of the heaviest application in terms of data.

Design of WiMAX Network for Istanbul Universities With OPNET

WiMAX- Worldwide Interoperability for Microwave Access-is an innovation standard for long-separation extend remote systems that incorporate both portable WiMAX 802.16e and fixed WiMAX 802.16d associations. WiMAX hardware exists in two essential structures base stations, WiMAX base station can give an inclusion region to an exceptionally enormous zone up to a span of 6 miles, WiMAX Receiver is likewise called client premise gear like a collector hub in Antenna. Right now, Istanbul colleges are associated with utilizing WiMAX innovation that improves the system bit rate and inclusion zone. Explicit qualities for WiMAX parameters have been picked that improve the greater part of the WiMAX organize parameters, for example, the general system delay, Packet End-to-End Delay, Throughput, Load, Traffic handset, and Packet Delay Variation. In Istanbul, specialized college hub has explicit parameters, for example, in cell sweep 3km and bearer recurrence 3 GHz and Channel Bandwidth 4.5 MHZ and the quantity of subcarriers 1024 and different colleges that not quite the same as college to college this relying upon the number of parameters which every college is diverse in parameters however it has a similar receiving wire increase and transmission power.

A Baseband Wireless Spectrum Hypervisor for Multiplexing Concurrent OFDM Signals.

The next generation of wireless and mobile networks will have to handle a significant increase in traffic load compared to the current ones. This situation calls for novel ways to increase the spectral efficiency. Therefore, in this paper, we propose a wireless spectrum hypervisor architecture that abstracts a radio frequency (RF) front-end into a configurable number of virtual RF front ends. The proposed architecture has the ability to enable flexible spectrum access in existing wireless and mobile networks, which is a challenging task due to the limited spectrum programmability, i.e., the capability a system has to change the spectral properties of a given signal to fit an arbitrary frequency allocation. The proposed architecture is a non-intrusive and highly optimized wireless hypervisor that multiplexes the signals of several different and concurrent multi-carrier-based radio access technologies with numerologies that are multiple integers of one another, which are also referred in our work as radio access technologies with correlated numerology. For example, the proposed architecture can multiplex the signals of several Wi-Fi access points, several LTE base stations, several WiMAX base stations, etc. As it able to multiplex the signals of radio access technologies with correlated numerology, it can, for instance, multiplex the signals of LTE, 5G-NR and NB-IoT base stations. It abstracts a radio frequency front-end into a configurable number of virtual RF front ends, making it possible for such different technologies to share the same RF front-end and consequently reduce the costs and increasing the spectral efficiency by employing densification, once several networks share the same infrastructure or by dynamically accessing free chunks of spectrum. Therefore, the main goal of the proposed approach is to improve spectral efficiency by efficiently using vacant gaps in congested spectrum bandwidths or adopting network densification through infrastructure sharing. We demonstrate mathematically how our proposed approach works and present several simulation results proving its functionality and efficiency. Additionally, we designed and implemented an open-source and free proof of concept prototype of the proposed architecture, which can be used by researchers and developers to run experiments or extend the concept to other applications. We present several experimental results used to validate the proposed prototype. We demonstrate that the prototype can easily handle up to 12 concurrent physical layers.

3-D-Printed Circular Array for WiMAX Base Station

Circular arrays offer the ability to form directional beams throughout a full $\text{360}^{\circ }$ of azimuth coverage without the drawbacks of beam broadening and/or scan loss. These advantages make them an attractive choice for a Worldwide Interoperability for Microwave Access (WiMAX) base station antenna where the directional beams in any arbitrary direction facilitate range extension and throughput. In this letter, we demonstrate a metal plated-on-plastic 3-D-printed circular array that provides a low-cost design with simple manufacturing and provides performance suitable for WiMAX base station operation from 5.1 to 5.8 GHz.

A Conceptual Framework for Implementing a WSN Based Cattle Recovery System in Case of Cattle Rustling in Kenya

This study proposes a framework for remote identification and tracking of cattle movement based on wireless sensor networks (WSN), mobile communication, and unmanned aerial vehicles (UAVs). The proposed framework can be implemented for tracking cattle movement at the village level and extended to harsh terrain when recovering stolen animals in case of cattle rustling or theft. The system works by identifying and tracking the desired animal location and sending periodic location data at regular intervals to a database as well as availing the specific animal’s current location on demand through the Internet and text messages. The proposed cattle tracking and recovery system (CTRS) consists of a rumen sensor module, a WSN control unit, a Worldwide Interoperability for Microwave Access (WiMAX) gateway, WiMAX base stations, and a data center. Availing timely information about the location of the stolen animals could facilitate quick recovery of the animals while ensuring the safety of the security personnel involved in the recovery process. Speedy recovery of stolen animals also defeats the purpose of cattle rustling as the rustlers do not have the chance to use the animals for their intended purposes. The proposed system was tested through a MATLAB simulation experiment.

Mobile Telemedicine Implementation with WiMAX Technology: A Case Study of Ghana.

Telemedicine has become an effective means of delivering quality healthcare in the world. Across the African continent, Telemedicine is increasingly being recognized as a way of improving access to quality healthcare. The use of technology to deliver quality healthcare has been demonstrated as an effective way of overcoming geographic barriers to healthcare in pilot Telemedicine projects in certain parts of Kumasi, Ghana. However because of poor network connectivity experienced in the pilot projects, the success of the pilot networks could not be extended to cover the whole city of Kumasi and other surrounding villages. Fortunately, recent deployment of WiMAX in Ghana has delivered higher data rates at longer distances with improved network connectivity. This paper examines the feasibility of using WiMAX in deploying a city wide Mobile Telemedicine solution. The network architecture and network parameter simulations of the proposed Mobile Telemedicine network using WiMAX are presented. Five WiMAX Base Stations have been suggested to give ubiquitous coverage to the proposed Mobile Telemedicine sites in the network using adaptive 4×4 MIMO antenna configurations.

Outage Analysis of Mixed FSO/WiMAX Link

In this paper, we study the outage performance of a complex system consisting of a free-space optical (FSO)/radio-frequency (RF) link. Using radio over free-space optics technology, the FSO link carries Worldwide Interoperability for Microwave Access (WiMAX) signals from a core network to a WiMAX base station, delivering traffic to multiple end RF users. A novel closed-form analytical expression for overall outage probability is derived when $M$ -ary phase-shift keying ( $M$ -PSK) and $M$ -ary quadrature amplitude modulation ( $M$ -QAM) are applied. The analysis is performed when the FSO link is under the influence of the Gamma–Gamma turbulence, path loss, and misalignment between the transmitter and receiver apertures, and the RF part is influenced by the Gamma-shadowed Nakagami- $m$ multipath fading. To illustrate the usefulness of the derived expressions, we present some numerical results that enable us to estimate the effects of different transceiver and channel parameters on the outage probability. The results are used for optimizing the transmitter laser beam radius at the waist to achieve the minimal overall outage probability in the case of different conditions over the RF part. The numerical and simulation results show that multipath fading severity and shadowing spread over the RF part have a significant effect on the optimal value of the laser beam waist and can decrease the overall outage probability for several orders of magnitude.

The Internet in Nepal: WiMAX Broadband Service

In an attempt to understand the growth of Internet subscribers and the determinants of Internet infrastructure in Nepal, this chapter examines the growth of Worldwide Interoperability for Microwave Access (WiMAX) subscribers at the national level and the factors associated with WiMAX base stations at the district level. The findings suggest that the number of WiMAX subscribers will continue to grow steadily in the short term. Per capita income, population density, and total road length are positively associated with WiMAX infrastructure availability. Elevation has a negative association. The availability of WiMAX base stations also varies regionally. Although the Government of Nepal has recognized the importance of [broadband] Internet, it needs to address various issues to ensure that the Internet becomes an integral part of economic growth and development.

New Dynamic Resource Utilization Technique Based on Fractional Frequency Reuse

Worldwide interoperability for microwave access (WiMAX) base stations (BS) use the fractional frequency reuse (FFR) technique to control inter-cell interference in cellular networks. One of the challenges in FFR is the unused radio resource in the downlink (DL) sub-frame. This paper proposes a dynamic resource utilization approach to eliminate the resource wastage typical of the conventional FFR technique. The proposed approach not only enhances the radio resource utilization of the BS efficiently, but also takes into account the variations in the population density. We deal with the partial usage of sub-channel mode in the DL sub-frame of the WiMAX BS based on orthogonal frequency division multiplexing access. A new FFR data rate formula is derived based on theoretical analysis. Quantitative measurements demonstrate that the dynamic model gives optimal results, enhancing the conventional FFR in terms of a variety of metrics. The data rate, subcarrier efficiency, and spectral efficiency are increased by 2.176 Mbps, 0.14 bit/subcarrier/burst, and 0.218 bps/Hz, respectively. In addition, in the new approach, the DL sub-frame is fully utilized (100 %), the number of served users is increased by 28.57 %, and the number of utilized slots is increased by 34.48 %. The effective utilization of resources and bandwidth characteristic of this approach makes it a strong candidate for BS deployment in cellular networks where the user density changes constantly.

A Wideband Dual-Polarized Antenna Using Planar Quasi-Open-Sleeve Dipoles for Base Station Applications

A wideband dual-polarized antenna for WLAN, WiMAX, and LTE base station applications is presented in this paper. The proposed antenna consists of two pairs of orthogonal planar quasi-open-sleeve dipoles along the centerlines, a balanced feeding structure and a square ground plane. The planar quasi-open-sleeve dipole comprises a pair of bowtie-shaped planar dipoles with two parallel curve parasitic elements. The introduced parallel curve parasitic elements change the path of the current of the original bowtie-shaped planar dipoles at high frequencies and hence wideband characteristic is achieved. Two pairs of the planar quasi-open-sleeve dipoles placed orthogonally further broaden the bandwidth of the antenna with dual-polarization characteristics. The proposed antenna achieves a 10-dB return loss bandwidth from 2.32 to 4.03 GHz (53.9% bandwidth) using the planar quasi-open-sleeve dipole structures. The isolation between the two ports remains more than 32 dB in the whole bandwidth. Measured results show that the proposed antenna keeps the cross-polarization under −33 dB and the front-to-back ratio better than 15 dB in the operating band. The antenna has an area of 0.3λ × 0.3λat 2.32 GHz making it easy to be extended to an array element.

OPTIMAL RESOURCE ALLOCATION FOR LAYERED VIDEO MULTICASTING IN WIMAX

Real-time video disseminations over wireless links such as video telephony, video conferencing and mobile TV have become fast growing applications. In order to cope with the increasing users’ demand, a new scalable and efficient wireless distribution platform is needed. With numerous advantages such as QoS assurance, high data rate and wide coverage, WiMAX has been regarded as an ideal choice to provide ubiquitous access for multimedia applications. However, how to achieve effective layered video multicasting in WiMAX networks is a challenging issue. In this study, we propose a utility-based resource allocation mechanism for layered video multicasting. In the proposed approach, Application-Layer Forward Error Correction (AL-FEC) is employed to deal with inevitable packet loss. Thus, for each video layer, WiMAX base stations can jointly choose a proper Modulation-and-Coding Scheme (MCS) and AL-FEC overheads to transmit. Our goal is to maximize the system utility which comprises two important factors, system reward and resource usage. System reward represents the summation of video quality of all subscribers while resource usage denotes the consumed WiMAX resources in terms of time slots. To efficiently obtain the optimal solution, we propose two heuristic algorithms, namely genetic algorithm and Layered Policy Iteration (LPI) algorithm and compared their performance to the optimal solution found by exhaustive search. We demonstrate the performance of the approaches via extensive simulations. The simulation results show that the LPI algorithm can provide great service quality and utilize system resource effectively.

Quantification of Design Challenges and Performance Assessment of WiMAX Resource Allocation Algorithms

Resource allocation management is one of the effective factors in the performance of WiMAX base station. Various goals could be achieved when the resource allocation scheme exploits in the right direction. However, resource allocation schemes lack a uniform assessment metrics. Where, most of the researches trying to show author's perspective in the results to show design pros, whilst the overall performance in resource allocation perspective is mostly missing. This paper presents the coordination between goals and design parameters that must be considered in the design phase to exploit the available features of the PHY and MAC layers and avoid the limitations. Moreover, this paper proposes a new method of primary assessment for resource allocation algorithms to ease conducting a fair comparison between the relevant algorithms. The assessment methodology based on a set of evaluation questions. The obtained results showed that the new assessment method distinguishes the overall performance to provide fair comparison.

OPNET BASED SIMULATION AND INVESTIGATION OF WIMAX NETWORK USING DIFFERENT QOS

IEEE 802.16 WiMAX network is designed for providing high speed wide area broadband wireless access. WiMAX is an emerging wireless technology which is used for creating multi-hop mesh networks offering variable and high data rates, QoS, seamless mobility within a network. OPNET modeler is a simulation program tool used to simulate the different types of wireless networks. In this paper, simulation and evaluation of three different sized networks (small, medium, large) is carried out. We are using the modeler to study networks with 15, 25 and 40 mobile workstations. In each network, group of five WiMAX workstations connect and call each other through one WiMAX base stations during 1000sec. Performance of parameters that indicate the quality of services such as initial ranging activity, delay, total transmission power and PHY path loss have been studied.

Design of a Dual-Band High-Gain Antenna Array for WLAN and WiMAX Base Station

A dual-band $3 \times 2$ antenna array with high gain is presented in this letter. A dual-band folded dipole antenna is utilized as the antenna array element. A broadband symmetric feed network is designed to maintain each array element with the identical current magnitude and phase. The antenna array has a low profile of 12 mm (about $0.1{\lambda _{\rm L}}$ ; ${\lambda _{\rm L}}$ is the wavelength in free space at the lowest operating frequency). Dual bands $2.3\!\sim\! 2.56$ and $3\!\sim\! 4.2~\hbox{GHz}$ for return loss (RL) being higher than 10 dB can be obtained in simulation, while two 10-dB RL bands $2.31\!\sim\! 2.51$ and $3.1\!\sim\! 4.15~\hbox{GHz}$ in measurement cover the wireless local area network (WLAN, $2.4\!\sim\! 2.48~\hbox{GHz}$ ) and Worldwide Interoperability for Microwave Access (WiMAX, $3.3\!\sim\! 3.8~\hbox{GHz}$ ). The measured results also show that this planar antenna array has a high gain $14.3\!\sim \!15.1~\hbox{dBi}\;(2.31\!\sim\! 2.51~\hbox{GHz})$ , $16.2\!\sim\! 17.3~\hbox{dBi}$ ( $3.1\!\sim\! 4.15~\hbox{GHz}$ ) in $ + { z}$ -direction and a low cross-polarization level $ .

A beacon-based handover scanning mechanism with QoS support in WiMAX femtocell architecture

WiMAX femtocell architecture has gained a lot of attention because of its better indoor service provision through traffic sharing between WiMAX and femtocell. However, since the signal of a WiMAX base station (BS) is usually stronger than that of a femtocell base station (fBS), the handover procedure of mobile stations may not be triggered due to the stronger signal association. And, a huge number of fBSs deployed within a WiMAX BS coverage area will require extra power to scan all fBSs for a handover determination. In this article, we propose a beacon-based handover scanning mechanism with Quality of Service (QoS) support. Through the modified beacons and MOB_NBR-ADV messages, a neighbor cell list with QoS parameters is generated automatically at each mobile station. The decision criteria for handover triggering and an appropriate target cell selection are also presented. The QualNet simulation results demonstrate that along with increased fBSs, the proposed mechanism can improve the total system throughput from 37% to 51% and obtain higher bandwidth utilization in the case of increasing number of fBSs, as compared with Full Scan and Neighbor Cell Information Mechanisms.

A Novel Multi-Service Small-Cell Cloud Radio Access Network for Mobile Backhaul and Computing Based on Radio-Over-Fiber Technologies

Small-cell systems based on cloud radio access network (cloud-RAN) architecture have been proposed as promising solutions to meet the capacity demand of the future wireless access networks in a cost-effective and power-efficient way. High-speed and scalable backhaul links between the centralized baseband processing units (BBUs) and the remote antenna units (RAUs) are very important to support the small-cell cloud-RAN. Conventionally, digital baseband I/Q samples are transmitted in the cloud-RAN backhaul, which puts stringent requirements on backhaul bandwidth, latency, and jitter. In this paper, we propose a novel multi-service small-cell wireless access architecture based on radio-over-fiber technologies (cloud-RoF access network). By utilizing analog radio frequency (RF) signal transmission in the optical backhaul links, high-speed data transmission can be achieved with highly simplified RAU design. In addition, by combing RoF with optical wavelength division multiplexing (WDM) techniques, multiple bands, multiple services and multiple operators can coexist in a shared optical infrastructure without interference. Two-operator coexistence in a shared small-cell cloud-RoF access network is demonstrated in an in-building testbed by using off-the-shelf optoelectronic components and commercialized WiMAX base stations and clients. In addition, the feasibility of delivering both conventional wireless services and future-proof millimeter-wave services is also demonstrated in the proposed multi-service small-cell cloud-RoF access system.

IMS-based distributed multimedia conferencing services for next-generation mobile networks

Distributed architecture offers many advantages compared to centralized architecture in terms of providing multimedia services. However, as a trade-off, distributed architecture requires that peers contribute a portion of their bandwidth and computational capacity to maintain the mutual overlay interconnection. This requirement develops into a serious problem for mobile users and wireless infrastructure, as the radio resource in this network is tremendously expensive, based on 3gpp (2005), and is one of the reasons why distributed architecture has not been widely applied in next-generation (4G) networks. It is also the main reason why multimedia services such as video conference have to rely on a costly centralized architecture built over an expensive media resource function controllers via the Internet protocol (IP) multimedia subsystem (IMS). This research work proposes a new distributed architecture utilizing intelligence and extra capacity, currently available on LTE and WiMAX base stations to reduce the required bit rates that each peer has to provide in order to maintain the overlay network. This reduction saves valuable radio resources and allows a distributed architecture to provide video conferencing services on 4G networks, with all the advantages of a distributed architecture such as flexibility, scalability, smaller delay, and lower cost. In addition, this can be implemented with a minimum modification of the standardized IMS platform and the 4G infrastructure, thereby saving the operators and service providers from excessive investments. A prototype has been built to prove the feasibility of the proposed architecture and evaluate its performances. The results show that our proposed distributed video conferencing service can actually reduce the average bandwidth required for data and signaling messages at wireless mobile terminals while maintaining the main operations of a video conference session.

WiMAX traffic analysis and base stations classification in terms of LRD

AbstractThe goal of this paper is to highlight the particularities of Worldwide Interoperability for Microwave Access (WiMAX) traffic from a long‐range dependence perspective. The application presented in this paper consists in the estimation of the quality of base stations (BS) positioning in the architecture of a WiMAX network. Analysing the traffic of the considered WiMAX network, with an original data mining methodology based on long‐range dependence, we determine which BS have a correct position in the topology of the network and which BS have an incorrect position. These BS must be repositioned when the next session of the network maintenance will take place.

WiMAX-based robust localization in the presence of misbehaving and/or malicious base stations

The use of WiMAX cellular networks has arisen as a promising solution in order to provide broadband access over large, often shadowed, areas. As in other cellular networks, localization of users is extremely useful for many services and even essential for some civilian and/or military logistic operations. In a cellular WiMAX network, a node can obtain its position from beacons received by several cell base stations. Therefore, securing the localization method against potential false or erroneous feedback is of paramount importance in order to allow the nodes to get reliable position estimations. This fact implies not only making the localization method robust against erroneous or forged measurements, but also identifying which WiMAX base stations are providing such measurements. In this paper, we propose a robust localization method that can identify up to k malicious or misbehaving base stations and provide with an accurate estimation of the node position even in their presence. Simulation results prove that this proposal outperforms other existing detection techniques.

A Cross-Layer Qos Based Scheduling Algorithm WRR Design in Wimax Base Stations

The IEEE 802.16 standard defines a wireless broadband access network technology called Wimax. It introduces several advantages, one of which is the support for Quality of Service (QoS) at the MAC level. To ensure meeting the QoS requirements, the 802.16 base stations must run some algorithms to allocate slots between connections. Call admission and scheduling are the strongest tools in our hand to ensure QoS. We propose an efficient design architecture that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the 802.16 network parameters. To test the proposed solution, we have implemented a cross layer between the 802.16 MAC and the network layers in the NS-2 simulator and, then in RTL level with VHDL to be designed in FPGA. Several simulation scenarios are presented. According to the simulation results, the proposed scheduling solution ensures the QoS requirements of all 802.16 service classes. The solution shares free resources weighted fairly and demonstrates work-conserving behavior. The proposed design in this paper was analyzed: simulation results show a significant performance improvement in terms of overall throughput and delay when compared to recently published work.