Cooperative Communication over Multi-Scale and Multi-Lag Wireless Channels

The development of wireless communication applications in the last few years is unprecedented. Wireless communication has evolved in various ways. The next generation of wireless systems should service more users while supporting mobility and high data rates. These requirements necessitate efficient use of available resources to provide...

Distributed beam forming with phase-only control for green cognitive radio networks

Cognitive radio (CR) is an intelligent radio system and is able to share the spectrum with licensed users (LU). By adopting adaptive beam forming techniques, CR can reuse the spectrum with LU via directing main beams towards CR users while displaying nulls towards LU. In this article, we present a new distributed beam forming (DB) technique, and...

Performance analysis of the cooperative ZP-OFDM: Diversity, capacity and complexity

In this paper, we investigate the diversity, capacity and complexity issues of cooperative Zero-Padding (ZP)-Orthogonal FrequencyDivisionMultiplexing (OFDM) communication. We consider cooperative ZP-OFDM communication over a multipath Rayleigh channel and with multiple Carrier Frequency Offsets (CFOs) existing at different relays. We use a...

Efficient radio transmission with adaptive and distributed beamforming for intelligent WiMAX

In this paper, we introduce Adaptive Beamforming (AB) and Distributed Beamforming (DB) as two efficient techniques for IntelligentWiMAX (I-WiMAX). I-WiMAX is a new maritime communication system, consisting of Smart Radio (SR) principles and mobile WiMAX based on the IEEE 802.16e standard. Adopting AB, the same spectrum can accommodate more users...

An investigation on the sensitivity of wavelet packet modulation to time synchronization error

Wavelet Packet based Multi-Carrier Modulation (WPMCM) offers an alternative to the well-established OFDM as an efficient multicarrier modulation technique. It has the advantage of being a generic transmission scheme whose actual characteristics can be widely customized to fulfill several requirements and constraints of advanced communication...

OFDM Communications with Cooperative Relays

Signal fading due to multi-path propagation is one of the major impairments to meet the demands of next generation wireless networks for high data rate services. To mitigate the fading effects, time, frequency, and spatial diversity techniques or their hybrid can be used. Among different types of diversity techniques, spatial diversity is of...

Robust Bases for Spectrum Pooling Systems on Wavelet Packet Multi-carrier Modulation MIMO Architecture

Cognitive Radio Dynamic Access Techniques for Mutual Interference Reduction and Efficient Spectrum Utilization

Performance Evaluation of WPMCM with Carrier Frequency Offset and Phase Noise

Wavelet Packet based Multi-Carrier Modulation (WPMCM) offers an alternative to the well-established OFDM as an efficient multicarrier modulation technique. It has strong advantage of being a generic transmission scheme whose actual characteristics can be widely customized to fulfill several requirements and constraints of an advanced...

Construction of Optimum Wavelet Packets for Multi-Carrier Based Spectrum Pooling Systems

The growing popularity of wireless applications has placed enormous burden on valuable resources such as spectral bandwidth. This has brought about a major revamp of traditional resource allocation policies culminating in an explosion of research activity in the field of cognitive radio (CR) (Mitola, Cognitive radio: an integrated agent...

Mitigation of wideband interference on UWB-IR transmission using multi-carrier templates

Ultra wideband (UWB) wireless systems are highly susceptible to interference from other services. To reduce the effect of interference from co-existing sources such as the WLAN standard IEEE 802.11a on UWB Communication, the construction of a modified template waveform using multi-carrier sinusoids is proposed in Ohno and Ikegami (2003), Ohno et...

Cognitive radio modulation techniques

Link Budget Analysis and Modeling of Short-Range UWB Channels

Ultrawideband (UWB) technology is an attractive alternative for short-range applications, e.g., wireless personal area networks. In these applications, transmit and receive antennas are very close to each other and the far-field condition assumed in most of the link budget models may not be satisfied. Under near-field conditions, variations in...

Cognitive Radio with Single Carrier TDCS and Multicarrier OFDM Approach with V-BLAST Receiver in Rayleigh Fading Channel

This article presents the performance comparison of TDCS and OFDM based cognitive radio for MIMO system using VBLAST receiver architecture to reconstruct the transmitted data. The interference avoidance performance in terms of BER and bitrate are improved by adding multiple antennas to the system and the use of V-BLAST technique at the receiver....

An overview of ultra wide band indoor channel measurements and modeling

Wireless Channel Modeling and Code Division Multiple Access for Indoor Communications