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In this paper the experimental results of research of the possibility of WiMax standard to be used for the organization of data channels in an integrated control system of earth-moving machines. There are shown the results of experimental studies of five steps: receiving of spectrogram; checking throughput of the base station sectors; researching the registering of mobile station with the base station;...
In this paper, a Multiband Low Noise Amplifier (LNA) for receiver system is designed to work at 950 MHz, GHz, 2.2 GHz, and 2.4 GHz centre frequencies. It was designed using HJ-FET NE32500 transistor which has self bias characteristics. Through Electronic Design Automation (EDA) simulations, the design performance of multiband LNA is analyzed and parameters such as Gain, Return loss, Noise Figure and...
With increased demand of high data rates with mobility, broadband wireless services have seen tremendous growth in recent past years. The mobile Worldwide Interoperability for Microwave Access (WiMAX) is based on IEEE 802.16 standard and is used for wireless Metropolitan Area Network (MAN). The IEEE 802.16 standard supports high data rate and high capacity in mobile Broadband Wireless Access (BWA)...
In recent years, the immense and ubiquitous coverage area of vehicular network is growing very frequently as the computational power and deployment of modern vehicle's wireless connectivity and their service facilities are raised. VANET (Vehicular Ad hoc Network) have become an orientation to the researchers and users both for inventive utilization of wide range of safety and non-safety applications...
A continuous-switching type array antenna receiver has been proposed in order to reduce the deterioration due to fast-fading channel variations and improve communication performance. The receive antennas are placed in a linear array, and by sequentially switching the elements in the opposite direction to the direction of the train travel, it has been possible to fix the signal receiving point virtually...
In this paper, an empirical path loss model is proposed for a WiMAX network operating on a carrier frequency of 2.63GHz for a rural terrain condition. This model is developed by means of real time measurements which are conducted on a deployed BSNL WiMAX network at Kuchinda, Sambalpur district, Odisha. The real time data like received signal strength indicator (RSSI),Carrier to interference plus noise...
A sequentially switched antenna array receiver (SSAAR) has been developed in order to lessen the fast-fading effects on super-express trains. The array elements are switched in reverse sequence to the direction of the train motion. To demonstrate the performance improvements, measurements were made using a scale model train with receiver moving at 3.6 km/h. A software simulation based on the Worldwide...
IEEE802.16j is the specification for WiMAX mobile multi-hop relay system. It is compatible to IEEE802.16e and supports mobility as well as IEEE802.16 PMP. As relay stations have changed the structure of traditional WiMAX network, the reasonable placement of base station and relay station can affect the result of network construction significantly. Firstly, the related work of research on planning...
In this paper we address an aspect of the mutual influence between the PHY layer budding blocks (FEC Blocks) and the MAC level allocations in the Uplink and Downlink of IEEE 802.16e/WiMAX networks. In these networks it is possible to transmit MAC level frames, denoted MAC PDUs, such that a PDU contains an integral number of fixed size Data Blocks. PDUs are transmitted over PHY Bursts, which are divided...
The Digital Down Converter also known as the DDC is one of the most integral parts of a baseband wireless receiver system. The major function of the DDC is to down convert an Intermediate Frequency (IF) signal to Baseband. It achieves this by performing complex tasks such as mixing, decimation and filtering and it is due to this reason, the architecture of the DDC occupies a significant on-chip area...
The well-established low-cost broadband OFDM based wireless systems in license-exempt bands, including worldwide interoperability for microwave access (WiMAX) systems, have drawn considerable attention for radar related applications over the past decade. This paper explores an idea of utilizing Commercial Off-The-Shelf (COTS) WiMAX base stations (BSs) in unlicensed band for monostatic airborne synthetic...
In the 4G communications standards, including Worldwide Interoperability for Microwave Access (WiMAX) and Long Term Evolution (LTE), Automatic Repeat reQuest (ARQ) is one of the important tools to coop with error-prone transmission environments. The primary function of ARQ is to provide reliable communication between a transmitter and its receivers through the retransmission of lost ARQ blocks. The...
The aim of this paper is to propose a compensation strategy that is able to easily identify the model of the In-phase/Quadrature (I/Q) impairments of Radio-Frequency (RF) direct-conversion devices and to efficiently compensate these unwanted effects. In fact, direct-conversion transmitters that integrate analog and digital components introduce a wideband frequency-dependent I/Q mismatch that strongly...
This paper presents an RF system-level design of a Spectrum Sensing Direct Conversion Receiver for Cognitive Radios. An extension to the recently developed IEEE 802.22 standard from 54MHz to 4GHz is proposed to take advantage of additional underused frequency bands. The proposed architecture is designed to detect IEEE 802.22, IEEE 802.16, and LTE signals as incumbents. The receiver is composed of...
Radar and communication system interoperability is an ongoing problem that is increasing due to acute spectral crowding. This paper will focus on examining the performance degradation to radar system receivers from OFDM communication signals such as WiMAX and LTE. Specifically, a simulated S-Band long range weather radar will be subjected to OFDM interference and the performance degradation measured...
As an attempt to improve throughput of WiMAX system, the oversampled WiMAX receiver is presented in this paper. Oversampling samples each transmitted symbol more than one time. Thus, several signal sequences which contain different information about channel may be obtained at the receiver. This study presents throughput of the oversampled WiMAX system that obtained by simulation over a realistic channel...
The Multicast/Broadcast Service (MBS) feature of mobile WiMAX network is a promising technology for providing wireless multimedia, because it allows the delivery of multimedia content to large-scale user communities in a cost-efficient manner. In this phase, a WiMAX network that transmits multiple video streams encoded in a scalable manner to mobile receivers using the MBS feature is considered. Two...
Vehicular ad hoc networks (VANETs) drive new challenging research issues at different layers of the protocol pillar, from physical to application. Focusing on the medium access layer, one of the most promising and not yet fully explored option is the adoption of orthogonal frequency division multiple access (OFDMA). Besides guaranteeing high spectral efficiency and effective resource allocation, it...
Employing signals of opportunity for synthetic aperture radar (SAR) imaging is the subject of recent research. This paper presents concepts on the collection and processing of WiMAX OFDM waveforms to produce SAR ground images. A radar collection model is presented followed by the signal processing approach based on previously derived OFDM phase history models. Two multi-symbol match filter designs...
Space Time Block Codes (STBC) have shown remarkable performance for Multiple Inputs Multiple Output (MIMO) systems. The performance of STBC can be further enhance by knowing transmit channel side information. This paper investigates how to exploit the channel side information at the transmitter end for STBC-MIMO system using pre-coding methods. The mathematical model for designing the codebook for...
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