In this letter, we investigate cooperative diversity with relay selection over cascaded Rayleigh fading channels. particular, analyze the performance of a scheme for vehicular networks decode-and-forward (DF) protocol. Only "best" relay, which satisfies an index merit, is selected. We ignore direct transmission between source ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> ) and its destination...

In this paper, we investigate the performance of selection cooperation in presence imperfect channel estimation. particular, consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present lower upper bounds on SNR further provide closed-form expressions for average symbol error rate (ASER), outage probability...

In this paper, we analyze the effect of feedback delay and channel estimation errors on performance a decode-and-forward (DF) cooperative transmission scenario with relay selection. our selection scheme, only one best relay-to-destination (R → D) quality is selected among set relays that decode source information correctly. Specifically, destination terminal first estimates state (CSI) all active R D links then sends index to terminals via delayed link. Due time varying nature fading...

In this letter, we investigate the effect of feedback delay and channel estimation errors in a decode-and-forward (DF) cooperative network with relay selection. particular, consider multirelay scenario, where best is selected from subset relays that are able to decode source information correctly. selection destination terminal estimates relay-to-destination (R → D) state (CSI) sends index terminals via delayed link. We performance considered scenario terms average symbol error rate (ASER)...

In this study, the authors investigate outage probability of underlay cognitive radio systems with relay selection. particular, they consider a secondary multi-relay network operating in amplify-and-forward (AF) mode and only 'best' is selected, which satisfies an index merit. The proposed selection strategy takes into consideration effect primary user (PU) interference. That is, assume that exposed to unwanted interference from neighboring PU network. They derive closed-form expression...

In this letter, we investigate the performance of multiple-input multiple-output techniques in a vehicle-to-vehicle communication system. We consider both transmit antenna selection with maximal-ratio combining and combining. The channel propagation model between two vehicles is represented as n*Rayleigh distribution, which has been shown to be realistic for scenarios. derive tight analytical expressions outage probability amount fading post-processing signal-to-noise ratio.

Contrastive self-supervised representation learning methods maximize the similarity between positive pairs, and at same time tend to minimize negative pairs. However, in general interplay pairs is ignored as they do not put place special mechanisms treat differently according their specific differences similarities. In this paper, we present Extended Momentum Contrast (XMoCo), a method founded upon legacy of momentum-encoder unit proposed MoCo family configurations. To end, introduce cross...

In this paper, we investigate the performance of relay selection in an underlay cognitive radio system presence primary user (PU) interference. particular, consider a secondary multi-relay network operating amplify-and-forward (AF) mode and only "best" which satisfies index merit is selected. The proposed strategy takes into consideration effect PU interference, i.e., assume that exposed to unwanted interference from neighboring network. We derive closed-form outage probability expression...

In this paper, we investigate the performance of selection cooperation in presence imperfect channel estimation. particular, consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present lower upper bounds on SNR derive closed-form expressions for average symbol error rate (ASER), estimation errors. A simulation...

The authors investigate the effect of feedback delay on average capacity a decode-and-forward cooperative network with relay selection. In particular, multi-relay scenario is considered, where best selected from subset relays that are able to decode source information correctly. this selection scenario, assume destination terminal estimates relay-to-destination (R→D) channel-state-information perfectly and sends index terminals via delayed link. performance considered in terms capacity....

In this paper, we investigate the performance of selection cooperation in presence channel estimation errors. particular, consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present lower bound on SNR derive closed-form expressions for outage probability transmitted signal error. A simulation study presented to...

In this paper, we investigate the performance of selection cooperation in presence imperfect channel estimation. particular, consider a cooperative scenario with multiple relays and amplify-and- forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present lower upper bounds on SNR derive closed-form expressions for average symbol error rate (ASER), outage probability capacity per...

In this paper we propose a new noncoherent relay selection strategy for two-way cooperative networks. our proposed scenario, channel state information (CSI) or feedback link is not needed, neither nor data detection. We assume Mary frequency shift keying (FSK) modulation transmission scheme and decode-and-forward (DF) protocol system relaying method. Relay performed based on min-max criterion the received instantaneous signal energies at nodes. Furthermore, by using energy detectors both...

The time varying channel between transmitter and receiver in wireless communications necessitates the to be informed about periodically detection procedure. This paper introduces a geometrical model for matrix multiple-input multiple-output (MIMO) communication system, where is supposed fast fading.Then an auto regressive (AR) proposed variations at each instant, based on which LMS-like procedure tracking suggested increase period required training order data transmission rate. efficiency of...

In this paper, we investigate the performance of selection cooperation in presence channel estimation errors. particular, consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present an upper bound on SNR derive closed-form expressions for average capacity error. A simulation study presented to corroborate...

In this paper, we investigate the performance of selection cooperation in presence imperfect channel estimation. particular, consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. scheme, only "best" relay which maximizes effective signal-to-noise ratio (SNR) at receiver end is selected. We present lower upper bounds on SNR derive closed-form expressions for average symbol error rate (ASER), outage probability capacity per...

Combinatorial optimization finds an optimal solution within a discrete set of variables and constraints. The field has seen tremendous progress both in research industry. With the success deep learning past decade, recent trend combinatorial been to improve state-of-the-art solvers by replacing key heuristic components with machine (ML) models. In this paper, we investigate two essential aspects algorithms for optimization: temporal characteristics attention. We argue that task variable...

A very efficient approach to increase the quality of service (QoS) and capacity wireless communication systems is control transmit powers. The existing power schemes are mostly designed for adjustment in environments where channel varying slowly with time. However, these methods fail properly adjust powers when variations fast. In this paper an adaptive distributed algorithm proposed enhance tracking convergence ability fast time environments. This predicts responses adjusts using only local...

Time varying nature of uplink/downlink channels in wireless communications, calls for prior knowledge about the channel parameters receiver side. This accounts different techniques estimating so called between transmitter and receiver. In this paper beside using a model typical multi-input multi-output (MIMO) communication system, we propose new modified Kalman filter based method tracking variations time. An auto regressive (AR) is fitted to fluctuations, on which forthcoming predicted via...

Unsupervised representation learning methods like SwAV are proved to be effective in visual semantics of a target dataset. The main idea behind these is that different views same image represent the semantics. In this paper, we further introduce an add-on module facilitate injection knowledge accounting for spatial cross correlations among samples. This turn results distilling intra-class information including feature level locations and similarities between same-class instances. proposed...

Contrastive self-supervised representation learning methods maximize the similarity between positive pairs, and at same time tend to minimize negative pairs. However, in general interplay pairs is ignored as they do not put place special mechanisms treat differently according their specific differences similarities. In this paper, we present Extended Momentum Contrast (XMoCo), a method founded upon legacy of momentum-encoder unit proposed MoCo family configurations. To end, introduce cross...