Cognitive radio (CR) design aims to increase spectrum utilization by allowing the secondary users (SUs) coexist with primary (PUs), as long interference caused SUs each PU is properly regulated. At SU, channel-state information (CSI) between its transmitter and receiver used calculate maximum allowable SU transmit power limit interference. We assume that this CSI imperfect, which an important scenario for CR systems. In addition a peak received constraint, upper constraint also considered....

Simultaneous wireless information and power transfer (SWIPT) is a promising solution to increase the lifetime of nodes hence alleviate energy bottleneck constrained networks. As an alternative conventional harvesting techniques, SWIPT relies on use radio frequency signals, expected bring some fundamental changes design communication This article focuses application advanced smart antenna technologies SWIPT, including multiple-input multiple-output relaying techniques. These have potential...

We consider a dual-hop full-duplex relaying system, where the energy constrained relay node is powered by radio frequency signals from source using time-switching architecture, both amplify-and-forward and decode-and-forward protocols are studied. Specifically, we provide an analytical characterization of achievable throughput three different communication modes, namely, instantaneous transmission, delay-constrained delay tolerant transmission. In addition, optimal time split studied for...

We consider a multipair decode-and-forward relay channel, where multiple sources transmit simultaneously their signals to destinations with the help of full-duplex station. assume that station is equipped massive arrays, while all and have single antenna. The uses channel estimates obtained from received pilots zero-forcing (ZF) or maximum-ratio combining/maximum-ratio transmission (MRC/MRT) process signals. To significantly reduce loop interference effect, we propose two techniques: i)...

This paper focuses on the relay selection problem in amplify-and-forward (AF) cooperative communication with full-duplex (FD) operation. Different schemes assuming availability of different instantaneous information are studied. We consider optimal that maximizes FD channel capacity and requires global state (CSI) as well several sub-optimal policies utilize partial CSI knowledge such a) source-relay relay-destination links b) loop interference c) interference. To facilitate comparison,...

In this paper, we deal with the deployment of full-duplex relaying in amplify-and-forward (AF) cooperative networks multiple-antenna terminals. contrast to previous studies, which focus on spatial mitigation loopback interference (LI) at relay node, a joint precoding/decoding design that maximizes end-to-end (e2e) performance is investigated. The proposed precoding incorporates rank-1 zero-forcing (ZF) LI suppression node and derived closed-form by solving appropriate optimization problems....

We study the effect of outdated channel state information on outage and error rate performance amplify-and-forward (AF) relay selection, where only one out set available relays is activated. consider two variations AF namely best selection partial when based upon estimates. For both these variations, closed-form expressions for probability are obtained, along with approximate symbol in medium to high signal-to-noise-ratio (SNR) regime. The diversity gain coding above schemes also explicitly...

The use of in-band full-duplex (FD) enables nodes to simultaneously transmit and receive on the same frequency band, which challenges traditional assumption in wireless network design. capability enhances spectral efficiency decreases latency, are two key drivers pushing performance expectations next-generation mobile networks. In less than ten years, FD has advanced from being demonstrated research labs implemented standards, presenting new opportunities utilize its foundational concepts....

The performance of beamforming with antenna correlation in a two hop amplify and forward (AF) multiple input multiple-output (MIMO) relay network is analyzed. This consists single which used to the signal from source destination. destination are both equipped antennas, correlated space, while has antenna. In this paper, we derive new closed form expressions for outage probability density function received signal-to-noise ratio (SNR) at We also present exact symbol error rate AF MIMO network,...

We analyze the impact of antenna correlation on secrecy performance multiple-input multiple-output wiretap channels where transmitter employs transmit selection while receiver and eavesdropper perform maximal-ratio combining with arbitrary correlation. New closed-form expressions are derived for exact asymptotic (high signal-to-noise ratio in transmitter-receiver channel) outage probability.

We analyze the performance of a two hop channel state information (CSI)-assisted amplify-and-forward system, with co-channel interference at relay. The system's outage probability and average bit error rate (BER) in presence Rayleigh faded multiple interferers are investigated. derive an exact expression for accurate bound BER. Simulation results show validity analysis point out effect interference.

The performance of a two hop amplify-and-forward relay system, where the source-relay and relay-destination channels experience Rayleigh Rician fading respectively, is investigated. We derive exact lower bound expressions for outage probability average bit error probability, bounds become tight at high signal-to-noise ratios (SNR). Our results are verified through comparison with Monte Carlo simulations, we also illustrate positive impact factor on system performance.

In this paper, an energy harvesting dual-hop relaying system without/with the presence of co-channel interference (CCI) is investigated. Specifically, constrained multi-antenna relay node powered by either information signal source or via receiving from both and interferer. particular, we first study outage probability ergodic capacity free system, then extend analysis to interfering environment. To exploit benefit multiple antennas, three different linear processing schemes are...

We consider a multi-pair relay channel where multiple sources simultaneously communicate with destinations using relay. Each source or destination has only single antenna, while the is equipped very large antenna array. investigate power efficiency of this system when maximum ratio combining/maximal transmission (MRC/MRT) zero-forcing (ZF) processing used at Using array, transmit each (or both) can be made inversely proportional to number antennas maintaining given quality-of-service. At...

We consider a full-duplex (FD) decode-and-forward system in which the time-switching protocol is employed by multi-antenna relay to receive energy from source and transmit information destination. The instantaneous throughput maximized optimizing beamformers at time-split parameter. study both optimum suboptimum schemes. reformulated problem scheme achieves closed-form solutions terms of beamformer for some scenarios. In other scenarios, optimization formulated as semi-definite relaxation...

In certain applications, relay terminals can be employed to simultaneously deliver information and energy a designated receiver set of radio frequency (RF) harvesters, respectively. such scenarios, the that is preferable for transmission does not necessarily coincide with transfer, since corresponding channels fade independently. Relay selection thus entails tradeoff between efficiency amount transferred harvesters. The study this subject on which work mainly focuses. Specifically, we...

In real wireless communication environments, it is highly likely that different channels associated with a relay network could experience fading phenomena. this paper, we investigate the end-to-end performance of dual-hop fixed gain relaying system when source-relay and relay-destination Rayleigh/Rician Rician/Rayleigh scenarios respectively. Analytical expressions for cumulative distribution function signal-to-noise ratio are derived used to evaluate outage probability average bit error...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We analyze the impact of outdated channel state information due to feedback delay on performance amplify-and-forward relays with <formula formulatype="inline"> <tex Notation="TeX">$k$</tex></formula>th worst partial relay selection scheme. In our analysis, new expressions for system's outage probability and average bit error rate are derived. The effects rank chosen, SNR imbalance, correlation...

This paper studies the optimum performance boundaries of a two-hop multi-antenna amplify-and-forward (AF) relay system with energy harvesting (EH) receiver. The source and nodes employ orthogonal space-time block codes for data transmission. When instantaneous channel state information (CSI) is available, we design joint optimal precoders to achieve different tradeoffs between transfers, which are characterized by boundary rate-energy (R-E) region. For this purpose, optimization problem...

This paper investigates the impact of using outdated channel estimates for relay selection and signal amplification on performance amplify-and-forward (AF) relays under partial (PRS) opportunistic (ORS). In practice, state information (CSI) can occur due to feedback or scheduling delay. Both variable gain (VG) AF fixed schemes are considered. Outage probability, average bit error rate (BER) simplified high signal-to-noise ratio approximations derived. The effect parameters such as number...

In this paper, we investigate a downlink transmission algorithm for single-cell multiuser systems with two-dimensional (2-D) large-scale antenna array at the base station (BS) over Rician fading channels. We first derive some properties of channel's line-of-sight (LOS) component in scenario. Next, based on these and under assumption only statistical channel state information (CSI), i.e., LOS $K$-factor, BS, optimal beamforming vector each user maximizing an approximation ergodic sum rate....

In this article, we study the combination of NOMA and full-duplex operation as a promising solution to improve capacity next-generation wireless systems. We application transmission in cellular, relay cognitive radio networks, demonstrate achievable performance gains. It is shown that effects self-interference inter-user interference due can be effectively mitigated by optimizing/enhancing beamforming, power control, link scheduling techniques. also discuss research challenges future...

The sum rate performance of simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR- RIS) assisted full-duplex (FD) communication systems is investigated. reflection transmission coefficients STAR- RIS elements are optimized for the energy splitting mode switching protocols to maximize weighted system. underlying optimization problems non-convex, hence, successive convex approximation technique has been employed develop efficient algorithms obtain suboptimal...

Orthogonal frequency division multiplexing (OFDM) is used in many wired and wireless broadband communication systems because of its resilience the presence signal dispersion or multipath distortion. OFDM has not been practical optical bipolar waveform cannot be intensity-modulated direct detection (IM/DD) systems. A new unipolar form OFDM, asymmetrically clipped (ACO-OFDM), recently developed. For case an AWGN channel, we compare ACO- other modulation schemes. It shown that with 4-QAVI...