High Data Rate Wireless Applications Research Articles

V-Band Six-Port Interferometer Receiver: High Data-Rate Wireless Applications, BER and EVM Analysis, and CFO Compensation

V-Band Six-Port Interferometer Receiver: High Data-Rate Wireless Applications, BER and EVM Analysis, and CFO Compensation

DAI based wireless sensor network for multimedia applications

In Wireless Multimedia Sensor Network (WMSN), the time critical and delay sensitive applications like video, audio, image demands high bandwidth and transmission resources. The provision of Cognitive Radio (CR) can effectively utilize the available spectrum in the most appropriate way to provide high bandwidth in the Wireless Sensor Network (WSN) environment as Cognitive Radio sensor network (CRSN). The CR features are applicable in WMSN paradigm with required changes in transmission parameter for bandwidth hungry multimedia applications. In this paper, we propose an approach for setting up a cost-efficient and higher data rates communication in Wireless Multimedia Cognitive Radio Sensor Network (WMCRSN). The process analyses power allocation for sensor nodes by dynamic channel modelling and allocates power using multi-agent based Distributed Artificial Intelligence (DAI) in WMCRSN applications. The novelty in the approach lies in analyzing the real-time spectrum sensing outputs system for high data rate wireless multimedia applications. The DAI makes the process of power allocation in a smart way for having low latency based intra and inter cluster communication between sensor nodes. The performance parameters of the network, i.e. probability of detection and false alarm with the modelled error rates are presented. The mathematical analysis and simulation results justifies the feasibility and merits of the proposed method over conventional methods.

Antennas and Arrays for 60 GHz High Data Rate Wireless Applications

The 60 GHz band has approximately 7 GHz bandwidth with the frequency range 57-64 GHz worldwide. This band is unlicensed and the research for this band is going on very rapidly since last few years. This paper presents the technical review of high data rate 60 GHz technology and the development of antennas and arrays for 60 GHz applications. The paper covers the introduction to 60 GH bands for various regions. The advantages, the disadvantages and the potential applications of 60 GHz technology are discussed. The detailed propagation characteristics of 60 GHz band are presented and analyzed. Based upon analysis of the propagation characteristics of 60 GHz band, the requirements for antenna design are discussed. The antennas and the arrays design along with the challenges in antenna and array design for 60 GHz technology are presented. The detailed review of various types of 60 GHz antennas and arrays such as high gain antennas, 60 GHz antenna arrays, switched beam array systems, phased array systems etc are discussed and analyzed. Performance comparison of various antennas and arrays is also presented in this paper. The presented 60 GHz technology introduction, propagation characteristics analysis, antenna design types, parameters analysis, challenges etc are helpful in the antennas and arrays design for 60 GHz high data rate wireless systems.

Multiplexing Antenna System in the Non-Far Region Exploiting Two-dimensional Beam Mode Orthogonality in the Rectangular Coordinate System

A multiplexing antenna system is proposed for high data rate wireless transmission applications in the non-far region. The system is composed of two identical flat rectangular antennas directed toward each other and separated by a distance. Each antenna radiates four beam modes with 2-D orthogonality in the rectangular coordinate system by means of a passive and low-loss beam forming network. Thanks to the orthogonality relation among the modes up to four independent channels in the same direction with the same frequency and polarization can be carried and the signal demultiplexing is facilitated in the reception side. To validate the proposed concepts, the antennas have been designed and fabricated in the E-band around 78.5 GHz. Based on that, the multiplexing system has been experimentally tested. Good agreement between simulations and measurements has been obtained.

A Novel 60 GHz Wideband Coupled Half-Mode/Quarter-Mode Substrate Integrated Waveguide Antenna

A novel wideband substrate integrated waveguide (SIW) antenna topology, consisting of coupled half-mode and quarter-mode SIW resonant cavities, is proposed for operation in the 60 GHz band. This innovative topology combines a considerable bandwidth enhancement and a low form factor with compatibility with low-cost printed circuit board manufacturing processes, making it excellently suited for the next generation, high data rate wireless applications. Moreover, exploiting SIW technology, a high antenna-platform isolation is obtained, enabling dense integration with active electronics without harmful coupling. The computer-aided design process yields an antenna that covers the entire 57–64 GHz IEEE 802.11ad band with a measured fractional impedance bandwidth of 11.7% (7 GHz). The measured maximum gain and radiation efficiency of the prototype are larger than 5.1 dBi and 65%, respectively, within the entire impedance bandwidth.

A Folded Reflectarray Antenna With a Planar SIW Slot Array Antenna as the Primary Source

An integrated design of a planar source-fed folded reflectarray antenna (FRA) with low profile is proposed to achieve high gain for Q-band millimeter wave high data rate wireless communication applications. A planar substrate integrated waveguide (SIW) slot array antenna is adopted as the primary source to illuminate the proposed FRA. Considerations of the off-focus loss and the asymmetry E- and H-plane beamwidths loss of the planar source are thoroughly investigated to improve the aperture efficiency of the reflectarray antenna. A prototype is implemented and the experimental results are in good agreement with the predictions, which exhibit a measured |S 11 | less than -10 dB over the frequency band of 41.6-44 GHz, a maximum boresight gain of 31.9 dBi at 44 GHz with the aperture efficiency of 49% and a -3 dB gain drop bandwidth of 41.8-44.9 GHz. By integrating with the planar feed, the proposed folded reflectarray antenna benefits from its low-profile, low cost, and the ability of coplanar integration with millimeter wave planar circuits while maintaining the good performance in terms of gain and efficiency.

Performance analysis of Doppler shift effects on OFDM‐based and MC‐CDMA‐based cognitive radios

SUMMARYThe present development of high data rate wireless applications has led to extra bandwidth demands. However, finding a new spectrum bandwidth to accommodate these applications and services is a challenging task because of the scarcity of spectrum resources. In fact, the spectrum is utilized inefficiently for conventional spectrum allocation, so Federal Communications Commission has proposed dynamic spectrum access mechanism in cognitive radio, where unlicensed users can opportunistically borrow unused licensed spectrum, which is a challenge to obtain contiguous frequency spectrum block. This also has a significant impact on multicarrier transmission systems such as orthogonal frequency division multiplexing (OFDM) and multicarrier code division multiple access (MC‐CDMA). As a solution, this paper develops non‐contiguous OFDM (NC‐OFDM) and non‐contiguous MC‐CDMA (NC‐MC‐CDMA) cognitive system. The implementation of NC‐OFDM and NC‐MC‐CDMA systems provides high data rate via a large number of non‐contiguous subcarriers without interfering with the existing transmissions. The system performance evaluates NC‐OFDM and NC‐MC‐CDMA for mobile scenario where each propagation path will experience Doppler frequency shift because of the relative motion between the transmitter and receiver. The simulation results of this paper proved that NC‐OFDM system is a superior candidate than NC‐MC‐CDMA system considering the mobility for cognitive users. Copyright © 2013 John Wiley & Sons, Ltd.

Frequency-Shift Filtering for OFDM Systems and Its Performance Analysis

Orthogonal frequency division multiplexing (OFDM) technique has been widely used in high data rate wireless applications, but it suffers performance degradation at low signal-to-noise (SNR) regions due to the impairments caused by noise-induced channel estimation errors. In this article, we propose to use frequency-shift (FRESH) filtering technique to exploit temporal and spectral correlation of the OFDM signals for noise reduction purpose. A closed form time-varying minimum mean squared error (MMSE) expression has been derived to analyze the performance of FRESH filtering under additive white Gaussian noise (AWGN) and Rayleigh fading channels. The MMSE analysis carried out here can be a reference for the design of practical OFDM systems. In addition, theoretical SNR is analyzed in this article to show the performance gain achieved by FRESH filtering. The numerical results verify that the maximum SNR improvements offered by FRESH filtering are over 0.6 dB and 1.6 dB under AWGN and Rayleigh fading channels, respectively.

Efficacy of Multiband OFDM Approach in High Data Rate Ultra WideBand WPAN Physical Layer Standard using Realistic Channel Models

Multiband Orthogonal Frequency Division Multiplexing (MBOFDM) approach using UWB signals with short duration of pulses provide unique advantages in short-range high data rate wireless applications which include easy penetration through obstacles, high precision ranging and low processing power. In this paper a performance study on MB-OFDM is attempted for high data rate ultra wideband (UWB) WPAN physical layer standard according to modulation techniques such as QPSK, 16-QAM, 64-QAM etc. Different multipath components in the UWB channels are characterized by different delays and attenuation. The channel models chosen in simulation of MB-OFDM UWB communication system are different from standard UWB channels considering realistic multipath resolution and operating frequencies. In this research different amplitude fading statistics for UWB channel (IEEE 802.15.3a) are analysed. The BER performance of MB-OFDM UWB on modified UWB channel models are investigated through simulation study. It is observed that QPSK modulation for the MB-OFDM UWB system performs better than 16-QAM and 64-QAM in the CM3 (NLOS) and CM4 (NLOS) channel environment. We show that, at low data rate (55 Mbps) the MB-OFDM system performs better in the CM4 channel environment than in the CM3, CM2 and CM1 channel model due to its inherent frequency diversity. In high data rate (480 Mbps), the BER performance in CM1 channel model is found to be better than in CM2, CM3, CM4 channel model.

High-Rate Space–Time Coded Large-MIMO Systems: Low-Complexity Detection and Channel Estimation

In this paper, we present a low-complexity algorithm for detection in high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that achieve high spectral efficiencies of the order of tens of bps/Hz. We also present a training-based iterative detection/channel estimation scheme for such large STBC MIMO systems. Our simulation results show that excellent bit error rate and nearness-to-capacity performance are achieved by the proposed multistage likelihood ascent search (M-LAS) detector in conjunction with the proposed iterative detection/channel estimation scheme at low complexities. The fact that we could show such good results for large STBCs like 16x16 and 32x32 STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in excess of 20 bps/Hz (even after accounting for the overheads meant for pilot based training for channel estimation and turbo coding) establishes the effectiveness of the proposed detector and channel estimator. We decode perfect codes of large dimensions using the proposed detector. With the feasibility of such a low-complexity detection/channel estimation scheme, large-MIMO systems with tens of antennas operating at several tens of bps/Hz spectral efficiencies can become practical, enabling interesting high data rate wireless applications.