EURASIP Journal on Wireless Communications and Networking

http://link.springer.com/journal/13638

List of Papers (Total 2,849)

Estimation of Directions of Arrival by Matching Pursuit (EDAMP)

We propose a novel system architecture that employs a matching pursuit-based basis selection algorithm for directions of arrival estimation. The proposed system does not require a priori knowledge of the number of angles to be resolved and uses very small number of snapshots for convergence. The performance of the algorithm is not affected by correlation in the input signals. The ...

Opportunistic Carrier Sensing for Energy-Efficient Information Retrieval in Sensor Networks

We consider distributed information retrieval for sensor networks with cluster heads or mobile access points. The performance metric used in the design is energy efficiency defined as the ratio of the average number of bits reliably retrieved by the access point to the total amount of energy consumed. A distributed opportunistic transmission protocol is proposed using a combination ...

A Theoretical Framework for Soft-Information-Based Synchronization in Iterative (Turbo) Receivers

This contribution considers turbo synchronization, that is to say, the use of soft data information to estimate parameters like carrier phase, frequency, or timing offsets of a modulated signal within an iterative data demodulator. In turbo synchronization, the receiver exploits the soft decisions computed at each turbo decoding iteration to provide a reliable estimate of some ...

Factor-Graph-Based Soft Self-Iterative Equalizer for Multipath Channels

We consider factor-graph-based soft self-iterative equalization in wireless multipath channels. Since factor graphs are able to characterize multipath channels to per-path level, the corresponding soft self-iterative equalizer possesses reduced computational complexity in sparse multipath channels. The performance of the considered self-iterative equalizer is analyzed in both ...

A Receiver for Differential Space-Time -Shifted BPSK Modulation Based on Scalar-MSDD and the EM Algorithm

In this paper, we consider the issue of blind detection of Alamouti-type differential space-time (ST) modulation in static Rayleigh fading channels. We focus our attention on a -shifted BPSK constellation, introducing a novel transformation to the received signal such that this binary ST modulation, which has a second-order transmit diversity, is equivalent to QPSK modulation with ...

Analysis of a Combined Antenna Arrays and Reverse-Link Synchronous DS-CDMA System over Multipath Rician Fading Channels

We present the BER analysis of antenna array (AA) receiver in reverse-link asynchronous multipath Rician channels and analyze the performance of an improved AA system which applies a reverse-link synchronous transmission technique (RLSTT) in order to effectively make a better estimation of covariance matrices at a beamformer-RAKE receiver. In this work, we provide a comprehensive ...

Impact of Channel Estimation Errors on Multiuser Detection via the Replica Method

For practical wireless DS-CDMA systems, channel estimation is imperfect due to noise and interference. In this paper, the impact of channel estimation errors on multiuser detection (MUD) is analyzed under the framework of the replica method. System performance is obtained in the large system limit for optimal MUD, linear MUD, and turbo MUD, and is validated by numerical results for ...

IEEE 802.11 Wireless LANs: Performance Analysis and Protocol Refinement

The IEEE 802.11 protocol is emerging as a widely used standard and has become the most mature technology for wireless local area networks (WLANs). In this paper, we focus on the tuning of the IEEE 802.11 protocol parameters taking into consideration, in addition to throughput efficiency, performance metrics such as the average packet delay, the probability of a packet being ...

Transceiver Design Concept for Cellular and Multispot Diffusing Regimes of Transmission

A number of attempts have been made in an effort to combine the advantages of line-of-sight and diffuse configurations for indoor optical wireless communications via sophisticated combinations of elements that are characteristic for these architectures. A different approach has been followed in the present investigation, namely, developing a transceiver capable of operating in both ...

A Proxy Architecture to Enhance the Performance of WAP 2.0 by Data Compression

This paper presents a novel proxy architecture for wireless application protocol (WAP) employing an advanced data compression scheme. Though optional in WAP , a proxy can isolate the wireless from the wired domain to prevent error propagations and to eliminate wireless session delays (WSD) by enabling long-lived connections between the proxy and wireless terminals. The proposed ...

Adaptive Denoising and Equalization of Infrared Wireless CDMA System

Infrared has abundant, unregulated bandwidth enabling rapid deployment at low cost. However, safety limits on power emission levels (IEC825), large noise due to ambient lighting, and multipath dispersion remain as hurdles in diffused indoor environments. Especially, the high-frequency periodic interference produced by fluorescent lights is a major concern. Spread spectrum ...

Differential Amplitude Pulse-Position Modulation for Indoor Wireless Optical Communications

We propose a novel differential amplitude pulse-position modulation (DAPPM) for indoor optical wireless communications. DAPPM yields advantages over PPM, DPPM, and DH-PIM in terms of bandwidth requirements, capacity, and peak-to-average power ratio (PAPR). The performance of a DAPPM system with an unequalized receiver is examined over nondispersive and dispersive channels. DAPPM ...

Symbol and Bit Error Rates Analysis of Hybrid PIM-CDMA

A hybrid pulse interval modulation code-division multiple-access (hPIM-CDMA) scheme employing the strict optical orthogonal code (SOCC) with unity and auto- and cross-correlation constraints for indoor optical wireless communications is proposed. In this paper, we analyse the symbol error rate (SER) and bit error rate (BER) of hPIM-CDMA. In the analysis, we consider multiple access ...

Modelling and Optimising TinyTP over IrDA Stacks

TinyTP is the IrDA transport layer protocol for indoor infrared communications. For the first time, this paper presents a mathematical model for TinyTP over the IrDA protocol stacks taking into account the presence of bit errors. Based on this model, we carry out a comprehensive optimisation study to improve system performance at the transport layer. Four major parameters are ...

An Approach to Optimum Joint Beamforming Design in a MIMO-OFDM Multiuser System

This paper describes a multiuser scenario with several terminals acceding simultaneously to the same frequency channel. The objective is to design an optimal multiuser system that may be used as a comparative framework when evaluating other suboptimal solutions and to contribute to the already published works on this topic. The present work assumes that a centralized manager knows ...

Blind Channel Estimation for Space-Time Coded WCDMA

A new blind channel estimation technique is proposed for space-time coded wideband CDMA systems using aperiodic and possibly multirate spreading codes. Using a decorrelating front end, the received signal is projected onto a subspace from which channel parameters can be estimated up to a rotational ambiguity. Exploiting the subspace structure of the WCDMA signaling and the ...

A Practical Radiosity Method for Predicting Transmission Loss in Urban Environments

The ability to predict transmission loss or field strength distribution is crucial for determining coverage in planning personal communication systems. This paper presents a practical method to accurately predict entire average transmission loss distribution in complicated urban environments. The method uses a 3D propagation model based on radiosity and a simplified city ...

Cochannel Interference Mitigation and Cooperative Processing in Downlink Multicell Multiuser MIMO Networks

Recently, the remarkable capacity potential of multiple-input multiple-output (MIMO) wireless communication systems was unveiled. The predicted enormous capacity gain of MIMO is nonetheless significantly limited by cochannel interference (CCI) in realistic cellular environments. The previously proposed advanced receiver technique improves the system performance at the cost of ...

Design of FIR Precoders and Equalizers for Broadband MIMO Wireless Channels with Power Constraints

This paper examines the optimum design of FIR precoders or equalizers for multiple-input multiple-output (MIMO) frequency-selective wireless channels. For the case of a left-coprime FIR channel, which arises generically when the number of transmit antennas is larger than the number of receive antennas, the Bezout matrix identity can be employed to design an FIR MIMO precoder that ...

Iterative MIMO Turbo Multiuser Detection and Equalization for STTrC-Coded Systems with Unknown Interference

Iterative multiuser detection in a single-carrier broadband multiple-input multiple-output (MIMO) system is studied in this paper. A minimum mean squared error (MMSE) low-complexity multiuser receiver is derived for space-division multiple-access (SDMA) space-time trellis-coded (STTrC) systems in frequency-selective fading channels. The receiver uses MMSE filtering to jointly ...

Improving Capacity in LMDS Networks Using Trellis-Coded Modulation

Local multipoint distribution systems (LMDS), which are operating worldwide in the frequency range of 26 to 43 GHz, have large bandwidths of 0.1 up to 2 GHz but a limited area coverage of a few kilometers only. This is due to line-of-sight (LOS) constraints for reliable point-to-multipoint links as well as due to large propagation losses. The size of the macrocells illuminated by ...

Performance Analysis of Capacity of MIMO Systems under Multiuser Interference Based on Worst-Case Noise Behavior

The capacity of a cellular multiuser MIMO system depends on various parameters, for example, the system structure, the transmit and receive strategies, the channel state information at the transmitter and the receiver, and the channel properties. Recently, the main focus of research was on single-user MIMO systems, their channel capacity, and their error performance with space-time ...

Time-Slotted Multiuser MIMO Systems: Beamforming and Scheduling Strategies

We investigate the problem of scheduling for the uplink of a time-slotted multiuser multiple-input multiple-output (MIMO) system with sum capacity as the performance metric. We first consider scheduling users' transmissions for fixed transmit beamformers. Upper bounds for the sum capacity of the time-slotted system with the optimum scheduler are found via relaxing a set of ...