Terms Of Bit Error Probability Research Articles

Distributed switch and stay combining for selection relay networks

We propose an efficient combination of distributed switch and stay and selection relay that offers the best performance at high SNRs compared to conventional selection relay schemes and to incremental relaying schemes in conjunction with selection relay. Our results, in terms of bit error probability, confirm the benefit of the proposed scheme at high SNR regime. We also show that the high-SNR performance of the proposed scheme with more than two relays is dominated by the decode- and- forward relaying link.

Performance analysis of single relay selection in rayleigh fading

We provide closed-form expressions for the outage and bit error probability (BEP) of uncoded, threshold-based opportunistic relaying (OR) and selection cooperation (SC), at arbitrary signal to noise ratios (SNRs) and number of available relays, assuming decode-and-forward relays and Rayleigh fading channels. Numerical results demonstrate that SC performs slightly better in terms of outage probability; in terms of BEP, both systems may outperform one another, depending on the SNR threshold that determines the set of relays that participate in the forwarding process.

Irrational-Based Time-Hopping Modulation for UWB Communications

In this paper, an irrational-based modulation scheme suitable for ultrawide-bandwidth communications is proposed. By light of the desirable random behavior of the digits in the expansions of irrationals, this scheme turns out to possess a more powerful ability to remove most periodic components from the transmitted signal regardless of the distribution of the input binary symbols, even without the compression and scrambling block. Some feasible detecting methods are given accordingly, as well as the simulation result in terms of bit error probability versus E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> in additive white Gaussian noise channel.

Design of Optimum M-Phase Spreading Sequences of Markov Chains

We design M(≥3)-phase spreading sequences of Markov chains optimal in terms of bit error probabilities in asynchronous SSMA (spread spectrum multiple access) communication systems. To this end, we obtain the distributions of the normalized MAI (multiple access interference) for such systems and find a necessary and sufficient condition that the distributions become independent of the phase shifts.

Construction of Quasi-Cyclic LDPC Codes for AWGN and Binary Erasure Channels: A Finite Field Approach

In the late 1950s and early 1960s, finite fields were successfully used to construct linear block codes, especially cyclic codes, with large minimum distances for hard-decision algebraic decoding, such as Bose-Chaudhuri-Hocquenghem (BCH) and Reed-Solomon (RS) codes. This paper shows that finite fields can also be successfully used to construct algebraic low-density parity-check (LDPC) codes for iterative soft-decision decoding. Methods of construction are presented. LDPC codes constructed by these methods are quasi-cyclic (QC) and they perform very well over the additive white Gaussian noise (AWGN), binary random, and burst erasure channels with iterative decoding in terms of bit-error probability, block-error probability, error-floor, and rate of decoding convergence, collectively. Particularly, they have low error floors. Since the codes are QC, they can be encoded using simple shift registers with linear complexity.

Suboptimum coherent detection of orthogonal phase-modulated signals

A suboptimum scheme for coherent demodulation of orthogonal phase-modulated signals in the additive white Gaussian noise channel is proposed and analyzed in terms of bit error probability. It is analytically shown that the suboptimum scheme provides the bit error performance competitive to the conventional optimum scheme, while requiring much less implementation complexity.

On Maximum-Likelihood Detection for Non-coherent FH/BFSK in Multitone Jamming

We derive the optimum maximum-likelihood (ML) non-coherent detector for FH/BFSK systems in the environment of multitone jamming and additive white Gaussian noise with no aid of jamming state indication and the resultant signal-plus- jammer tone, which, however, were required in K. C. Teh’s previous work [1]. Because of the optimum ML detector’s huge complexity, a novel complexity-reduced scheme which is called joint-suboptimum maximum-likelihood (JSML) detector is proposed. Simulation results show the superiority of the proposed optimum ML and JSML detectors over other existing diversity combining approaches. The performance analysis in terms of bit error probability (BEP) for the JSML detector with single diversity in n = 1 and n = 2 band multitone jamming (BMJ) is provided and further validated by simulation results. In moderate and high SNR conditions, though the proposed JSML detector performs slightly worse than the optimum ML detector, it does achieve much complexity reduction.

MC-CDMA bit error probability and outage minimization through partial combining

This work addresses the performance evaluation, in terms of bit error probability (BEP) and bit error outage (BEO), for the down-link of multi-carrier code division multiple access systems. A partial combining technique depending on a parameter adapted to the system load and the mean signal-to-noise ratio is proposed to counteract both interference and thermal noise and optimized to minimize both BEP and BEO. The performance is improved with respect to previously known techniques such as maximal ratio combining, orthogonal restoring combining and equal gain combining.

On Bit Error Probabilities of SSMA Communication Systems Using Spreading Sequences of Markov Chains

We study asynchronous SSMA communication systems using binary spreading sequences of Markov chains and prove the CLT (central limit theorem) for the empirical distribution of the normalized MAI (multiple-access interference). We also prove that the distribution of the normalized MAI for asynchronous systems can never be Gaussian if chains are irreducible and aperiodic. Based on these results, we propose novel theoretical evaluations of bit error probabilities in such systems based on the CLT and compare these and conventional theoretical estimations based on the SGA (standard Gaussian approximation) with experimental results. Consequently we confirm that the proposed theoretical evaluations based on the CLT agree with the experimental results better than the theoretical evaluations based on the SGA. Accordingly, using the theoretical evaluations based on the CLT, we give the optimum spreading sequences of Markov chains in terms of bit error probabilities.

Performance Analysis and Optimization of a Space–Time Selective PIC for CDMA Systems

This paper deals with an efficient receiver for applications in direct sequence-code-division multiple access wireless communication systems. This receiver combines a modified scheme of a parallel interference cancellation detector with antenna arrays with optimum beamforming and is used at the base station for the detection of asynchronous user signals. Each user's transmission channel is assumed to be a multipath frequency-selective independent Rayleigh fading channel. The receiver operates by dividing the signals into reliable and unreliable sets following space-time combining. The reliable signals are detected and canceled from the whole signal received at each sensor. Unreliable signals are then detected to improve the decision reliability. The receiver performance in terms of bit-error probability is analytically derived and optimized. According to the analytical and simulation results, this receiver outperforms previously proposed schemes and, thanks to its low implementation complexity, real-time operation is achieved.

Bit error outage for diversity reception in shadowing environment

This letter addresses the problem of evaluating the bit error outage (BEO), i.e., the outage probability defined in terms of bit error probability, in a Rayleigh fading and shadowing environment. We consider coherent detection of binary phase-shift keying with maximal ratio combining (MRC). As an example application, the BEO in a log-normal shadowing environment is analyzed and the improvement in terms of BEO due to MRC is quantified in different shadowing environments.

Performance of RS-Coded DS/CDMA Microcellular Systems with M-ary Orthogonal Signaling

This paper investigates the application of Reed-Solomon coding on DS/CDMA systems with M-ary orthogonal signaling for the reverse link of a microcellular environment. The performance of voice and data communications are analytically evaluated for a Rician or Rayleigh faded channel with lognormal shadowing and a two-slope path loss model. The effects of sectorization and antenna diversity are also considered. Numerical results, in terms of bit error probability and throughput, show that with proper selection of the coding rate and spreading, the proposed system presents enhanced performance with moderate complexity.

Statistical channel modelling and performance evaluation in satellite personal communications

This paper is concerned with channel modelling for satellite personal communications and with the associated problem of performance evaluation. Channel characteristics for personal communications tend to differ from those traditionally accepted for vehicular communications. In this paper we report on modelling aspects for both wideband and narrowband personal communications. Then we consider performance evaluation for low-altitude earth orbit (LEO) satellite systems in terms of bit error probability and outage probability. To evaluate the outage probability for LEO systems, a tight and simple upper bound is finally provided. (C) 1998 John Wiley & Sons, Ltd.

Practical RAKE receiver architecture for the downlink communications in a DS-CDMA mobile system

The authors deal with a practical architecture for a RAKE receiver suitable for the downlink communication in a direct-sequence code division multiple access (DS-CDMA) mobile system. The proposed RAKE receiver makes use of a pilot signal broadcast by the base station to obtain channel parameter estimation and synchronisation. Computer simulations have been carried out in deriving the performance in terms of bit-error probability under typical multipath fading propagation conditions of GSM applications. Comparisons with an ideal RAKE receiver and with a multipath rejection receiver recently proposed in the literature, for the same type of downlink channel, are shown to highlight the good behaviour of the proposed receiver.

A novel procedure for jones' parameters estimation for M‐4QAM optical systems

AbstractA new procedure is proposed for estimating the State‐of‐Polarisation of the received optical signal in Four‐Quadrature Amplitude Modulation systems. The proposed solution, which is obtained on the basis of the Maximum Likelihood criterion, is merely electronic and operates in the presence of laser phase noise, photodetection noise and cross‐polarisation interference. It employs a suitably designed training sequence to estimate Jones' parameters in the data‐aided training mode. A proper decision‐directed procedure is then activated to lock‐in the estimated parameters in the operative mode. The variances of the resulting estimation errors are evaluated and the overall system performance is given in terms of Bit Error Probability versus signal‐to‐noise ratio. The theoretical analysis and the computer simulations show the superiority of the proposed recovery procedure with respect to alternative solutions recently proposed in literature.

A primer on turbo code concepts

The goal of this article is to describe the main ideas behind the new class of codes called turbo codes, whose performance in terms of bit error probability has been shown to be very close to the Shannon limit. In this article, the mathematical measures of a posteriori probability and likelihood are reviewed, and the benefits of turbo codes are explained in this context. Since the algorithms needed to implement the decoders have been well documented by others, they are only referenced here, not described in detail. A numerical example, using a simple concatenated coding scheme, provides a vehicle for illustrating how error performance can be improved when soft outputs from the decoders are used in an iterative decoding process.

Recursive carrier phase tracking for synchronous multilevel 4QAM receivers

Four-quadrature amplitude modulation (4QAM) allows high spectral efficiency in coherent optical data transmission by exploiting the two phases and the two polarizations of the propagating wave. In this paper the performance of 4QAM is analyzed in the presence of laser phase noise and photodetection noise. A decision feedback phase tracking scheme based on the Kalman filter and leading to a novel hybrid PLL structure is employed and its accuracy evaluated. The computational complexity of the proposed phase estimator is also discussed. The performance of the resulting 4QAM system is evaluated in terms of bit error probability versus the signal-to-noise ratio E/sub b//N/sub 0/, for different ratios of the symbol rate R/sub s/ over the laser linewidth B/sub L/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Teletext reception in a mobile channel for a broadcast tele-information system

A system is proposed for informing passengers who travel by train during their journey. An important part of the system is mobile communication. Teletext is chosen as an information medium, and the possibility of mobile teletext reception is analyzed considering selection diversity (SD) and maximal ratio combining (MRC). The bit error probability is calculated by modeling the channel as a shadowed-Rician fading channel. Picture quality is measured with average number of errors per page (ANEP). Thus performance is measured in terms of bit error probability (BER) and average number of errors per page. Finally, the level crossing rate, average fade, and average nonfade durations are also evaluated. >

Performance of microcellular mobile radio in a cochannel interference, natural, and man-made noise environment

A model is developed for performance analysis of a microcellular digital mobile radio system with Rayleigh-faded cochannel interference, Gaussian noise, and narrowband impulsive noise (Middleton's Class A noise) using the differential phase shift keying (DPSK) modulation technique. The desired signal is assumed to be Rician faded. The effects of selection diversity on the performance are investigated and compared to the nondiversity case. The performance is measured in terms of bit error probability and spectrum efficiency. The influence of reuse distance (i.e. cluster size), traffic intensity (i.e. blocking probability), impulsive index, Rician parameter, and turning point of the dual path loss law characteristic of microcells on the performance parameters is investigated in detail.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Monte carlo simulation off direct sequence spread spectrum for indoor radio communication in a rician fading channel

A Monte Carlo simulation was conducted to assess the performance, in terms of bit error probability, of a direct sequence spread spectrum multiple access (DS/SSMA) radio system in indoor Rician fading channels using differential phase shift keying (DPSK). Simulation results are presented for a DS/SSMA indoor radio system using selection diversity. Importance sampling techniques were used to accelerate the simulation. The results are compared with the analytical results obtained earlier