Goran T. Dordevic

Outage probability of decode-and-forward network with threshold based protocol over Rayleigh fading

In this paper, the outage performance for decode-and-forward cooperative networks is investigated. The analytical results for outage probability are derived in the case when network nodes communicate with each other over Rayleigh fading channel using a threshold based protocol, while Rayleigh propagation also is experienced over a channel between a node and the destination. Impact of signal-to-noise ratio values and number of nodes when maximum ratio combining is applied at the destination are analysed.

Effects of pointing errors on average capacity of FSO links over gamma-gamma turbulence channel

In this paper, we derive new closed-form expression for the average channel capacity of the free space optical (FSO) system with intensity-modulation/direct detection (IM/DD). The intensity fluctuations at receiver are described by combined model which assumes turbulence effects, pointing errors and path loss. The numerical results are presented. The effects of normalized jitter variance, propagation distance and turbulence strength are discussed.

Blind and robust 3D mesh watermarks

This paper discusses the performance a new robust, spatial, blind watermarking method for hiding encoded data into a geometric structure of the three-dimensional (3D) mesh model. By combining an algorithm for reliable host vertex selection and error correction codes, our watermarking neutralizes negative influence of optimization to watermark resilience. Using geometrical criteria, the algorithm selects mesh vertices with a minimum deletion probability in the optimization process. Selected vertices are then used by a quantizer for embedding the encoded watermark information. The watermark is reconstructed in a two step process involving the blind extraction of selected vertices and decoding of embeded data.

Error performance of uncoded and convolutional coded SC receiver over FSO channel with pointing errors

In this paper, the performance of intensity-modulated with direct detection (IM/DD) free space optical (FSO) system using the on-off keying is observed. Besides the gamma-gamma atmospheric turbulence degradation, the pointing errors and path loss are included. In order to mitigate degradation effects, the selection combining (SC) receiver is applied. After theoretical derivation of the bit error rate expression, the numerical integration is accomplished and confirmed by Monte Carlo simulations. Also, the BER performance is improved by using the convolutional coding, which is demonstrated by Monte Carlo simulations. Numerical results are presented and effects of normalized jitter, normalized beam width, propagation distance and number of SC apertures are observed.

Outage performance of cooperative relaying systems in interference-limited environment

Cooperative relaying technology is often used as an efficient solution for improving the performance of wireless communications systems. This technology has advantage of extending the coverage and increasing throughput without using large power at the transmitter. In this paper, the outage performance of dual-hop links with partial relay selection and co-channel interferers at both relay and destination in Rayleigh fading channel is investigated. The amplify-and-forward relaying is employed with the channel state information (CSI)-assisted relays requiring the CSI from the previous hop and from all co-channel interferers at the relay. The relay selection is based only on the instantaneous signal to interference ratio from the first hop. We provide an exact closed-form expression for the outage probability of the observed system. The numerical results obtained by the analytical approach are verified by Monte-Carlo simulations. The presented results are the part of a PhD thesis.

Dual-hop transmissions corrupted by interferences over asymmetric fading channels

This paper studies the outage probability of a dual-hop amplify-and-forward (AF) relay systems where the source-relay and the relay-destination channels experience Rayleigh and k-μ fading, respectively. The relay node is corrupted by Rayleigh faded multiple co-channel interferences. New infinite series expression for outage probability of the end-to-end signal-to-interference and noise ratio (SINR) for the channel-state-information (CSI)-assisted relay is derived.

Effect of phase noise on error performance of DE-QPSK receiver over k-μ fading channel

This paper presents the error performance analysis of differentially encoded coherent quadrature phase-shift keying (DE-QPSK) transmission over k-μ fading channel. The imperfections of the carrier signal recovery are taken into consideration through the phase-locked loop error, which is described by Tikhonov distribution. Based on novel derived expression for average bit-error probability (BEP), numerical results are obtained. The influence of loops bandwidth-bit time product and fading depth on the system performance is investigated.

Outage performance of switch-and-examine combining receiver over FSO Gamma-Gamma atmospheric turbulence with pointing errors

This paper presents the outage probability analysis of free-space optical (FSO) system with the switch-and-examine combining (SEC) receiver. In addition, the modification of SEC, called switch-and-examine combining with post-examining selection (SECps), is also analyzed. The intensity fluctuations of the received optical signal are accounted for both Gamma-Gamma atmospheric turbulence and pointing errors. The influence of the atmospheric turbulence parameters, as well as the normalized beam width and normalized jitter, on the outage probability performance is observed. Also, the effects of the switching and outage threshold and the number of the SEC and SECps diversity apertures on the FSO performance are discussed.

On the effect of imperfect reference signal recovery on BER performance of PSK receiver in composite fading channel

This paper presents an analysis of the quaternary phase-shift keying (QPSK) signal reception over the composite KG fading channel in the presence of imperfect reference signal recovery. Two cases are considered: the reception over a single channel and diversity reception. In the case of diversity technique applied, selection combining (SC) and dual branch switched-and-stay combining (SSC) were employed. The simultaneous influences of the imperfect reference signal recovery, composite fading severity and average signal-to-noise ratio in the channel on bit-error rate (BER) performance are determined and discussed.

Performance of MPSK signal predetection EGC diversity receiver

In this paper a performance analysis of modified M-ary phase-shift-keying (MPSK) signal diversity receiver with predetection equal gain combiner (EGC) will be presented. The modification is in introducing a structure that performs the estimation with remodulation (ER). The EGC combining is realized by using the constant modulus algorithm (CMA). The influence of carrier frequency offset, length of ER structure and other parameters of the receiver will be examined.