EURASIP Journal on Wireless Communications and Networking

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

List of Papers (Total 2,915)

On the Geometrical Characteristics of Three-Dimensional Wireless Ad Hoc Networks and Their Applications

In a wireless ad hoc network, messages are transmitted, received, and forwarded in a finite geometrical region and the transmission of messages is highly dependent on the locations of the nodes. Therefore the study of geometrical relationship between nodes in wireless ad hoc networks is of fundamental importance in the network architecture design and performance evaluation. ...

On the Use of Padé Approximation for Performance Evaluation of Maximal Ratio Combining Diversity over Weibull Fading Channels

We use the Padé approximation (PA) technique to obtain closed-form approximate expressions for the moment-generating function (MGF) of the Weibull random variable. Unlike previously obtained closed-form exact expressions for the MGF, which are relatively complicated as being given in terms of the Meijer G-function, PA can be used to obtain simple rational expressions for the MGF, ...

Outage Analysis of Ultra-Wideband System in Lognormal Multipath Fading and Square-Shaped Cellular Configurations

Generic ultra-wideband (UWB) spread-spectrum system performance is evaluated in centralized and distributed spatial topologies comprising square-shaped indoor cells. Statistical distributions for link distances in single-cell and multicell configurations are derived. Cochannel-interference-induced outage probability is used as a performance measure. The probability of outage varies ...

On-Off Frequency-Shift Keying for Wideband Fading Channels

-ary on-off frequency-shift keying (OOFSK) is a digital modulation format in which -ary FSK signaling is overlaid on on/off keying. This paper investigates the potential of this modulation format in the context of wideband fading channels. First, it is assumed that the receiver uses energy detection for the reception of OOFSK signals. Capacity expressions are obtained for the cases ...

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 ...

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 ...

Optical Wireless Sensor Network System Using Corner Cube Retroreflectors

We analyze an optical wireless sensor network system that uses corner cube retroreflectors (CCRs). A CCR consists of three flat mirrors in a concave configuration. When a light beam enters the CCR, it bounces off each of the three mirrors, and is reflected back parallel to the direction it entered. A CCR can send information to the base station by modulating the reflected beam by ...

Adaptive Blind Multiuser Detection over Flat Fast Fading Channels Using Particle Filtering

We propose a method for blind multiuser detection (MUD) in synchronous systems over flat and fast Rayleigh fading channels. We adopt an autoregressive-moving-average (ARMA) process to model the temporal correlation of the channels. Based on the ARMA process, we propose a novel time-observation state-space model (TOSSM) that describes the dynamics of the addressed multiuser system. ...

The Extended-Window Channel Estimator for Iterative Channel-and-Symbol Estimation

The application of the expectation-maximization (EM) algorithm to channel estimation results in a well-known iterative channel-and-symbol estimator (ICSE). The EM-ICSE iterates between a symbol estimator based on the forward-backward recursion (BCJR equalizer) and a channel estimator, and may provide approximate maximum-likelihood blind or semiblind channel estimates. Nevertheless, ...

Adaptive Space-Time-Spreading-Assisted Wideband CDMA Systems Communicating over Dispersive Nakagami- Fading Channels

In this contribution, the performance of wideband code-division multiple-access (W-CDMA) systems using space-time-spreading- (STS-) based transmit diversity is investigated, when frequency-selective Nakagami- fading channels, multiuser interference, and background noise are considered. The analysis and numerical results suggest that the achievable diversity order is the product of ...

A Complementary Code-CDMA-Based MAC Protocol for UWB WPAN System

We propose a new multiple access control (MAC) protocol based on complementary code-code division multiple access (CC-CDMA) technology to resolve collisions among access-request packets in an ultra-wideband wireless personal area network (UWB WPAN) system. We design a new access-request packet to gain higher bandwidth utilization and ease the requirement on system timing. The new ...

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 ...

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 ...

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 ...

Flexible Transmission Scheme for 4G Wireless Systems with Multiple Antennas

New air interfaces are currently being developed to meet the high requirements of the emerging wireless communication systems. In this context, the combinations of the multicarrier (MC) and spread-spectrum (SS) technologies are promising candidates. In this paper, we propose a generic transmission scheme that allows to instantiate all the combinations of orthogonal ...

Reconfigurable Signal Processing and Hardware Architecture for Broadband Wireless Communications

This paper proposes a broadband wireless transceiver which can be reconfigured to any type of cyclic-prefix (CP) -based communication systems, including orthogonal frequency-division multiplexing (OFDM), single-carrier cyclic-prefix (SCCP) system, multicarrier (MC) code-division multiple access (MC-CDMA), MC direct-sequence CDMA (MC-DS-CDMA), CP-based CDMA (CP-CDMA), and CP-based ...

Flexible Frequency Discrimination Subsystems for Reconfigurable Radio Front Ends

The required flexibility of the software-defined radio front end may currently be met with better overall performance by employing tunable narrowband circuits rather than pursuing a truly wideband approach. A key component of narrowband transceivers is appropriate filtering to reduce spurious spectral content in the transmitter and limit out-of-band interference in the receiver. In ...

Multicarrier Access and Routing for Wireless Networking

A multicarrier access and routing system has been proposed for use in wireless networks. Users within each cell access a radio port (RP). All RPs are connected to a radio exchange node (REN) which routes the calls or packets. The uplink access is orthogonal multicarrier code-division multiple access (MC-CDMA) and the downlink transmission is multicarrier orthogonal code-division ...

MAC Protocols for Optimal Information Retrieval Pattern in Sensor Networks with Mobile Access

In signal field reconstruction applications of sensor network, the locations where the measurements are retrieved from affect the reconstruction performance. In this paper, we consider the design of medium access control (MAC) protocols in sensor networks with mobile access for the desirable information retrieval pattern to minimize the reconstruction distortion. Taking both ...

An Optimal Medium Access Control with Partial Observations for Sensor Networks

We consider medium access control (MAC) in multihop sensor networks, where only partial information about the shared medium is available to the transmitter. We model our setting as a queuing problem in which the service rate of a queue is a function of a partially observed Markov chain representing the available bandwidth, and in which the arrivals are controlled based on the ...

Optimisation of Downlink Resource Allocation Algorithms for UMTS Networks

Recent interest in resource allocation algorithms for multiservice CDMA networks has focused on algorithms optimising the aggregate uplink or downlink throughput, sum of all individual throughputs. For a given set of real-time (RT) and non-real-time (NRT) communications services, an upper bound of the uplink throughput has recently been obtained. In this paper, we give the upper ...