Presence Of Co-channel Interference Research Articles

Performance Analysis of Cooperative Communication in the Presence of Co-channel Interference

Performance analysis without interference hypothesis can not be directly applied to the actual cooperative communication system. This paper focuses on interference model and performance analysis, and we investigate performance of amplify-and-forward (AF) cooperative communication system in the presence of co-channel interference. Simulation results show that: channel capacity and BER of AF collaboration systems are subject to a certain degree of loss because of co-channel interference. And with the increasing signal-to-noise ratio (SNR), the loss of properties is greater.

A tractable approach to analyzing the energy-aware two-way relaying networks in the presence of co-channel interference

Under the impact of co-channel interference (CCI) at two source nodes and the relay, we investigate the performance of dual-hop amplify-and-forward (AF) relaying networks. In terms of energy harvesting, the power-constrained relay first scavenges energy from the received signal and CCI signals then amplifies them and forwards them to the destination. In particular, we provide closed-form expressions for outage probability and bit error ratio (BER) to easily analyse the system performance. In this paper, the impact of distinct interference power level and the number of CCIs are derived. Monte Carlo simulations are used to provide expressions related to outage probability performance. It is confirmed that energy efficiency at the relay can be enhanced due to several advantages of CCI signals which can also prolong the life expectancy of relaying systems.

Impact of Cochannel Interference on the Performance of Quadrature Spatial Modulation MIMO Systems

Quadrature spatial modulation (QSM) was proposed recently as a viable multiple-input multiple-output (MIMO) communication technique for future wireless systems. QSM expands spatial modulation to include both real and imaginary spatial constellation symbols. In this letter, we consider an arbitrary QSM MIMO system operating over Rayleigh fading channels and in the presence of additive white Gaussian noise and cochannel interference (CCI). The performance of the system is analyzed mathematically and numerically. In particular, a closed-form expression for the pairwise error probability is derived assuming arbitrary number of CCIs and used to calculate an upper bound on the average error probability. As well, an asymptotic expression, which is shown to be tight at practical SNR values is derived. Analytical results are sustained through Monte Carlo simulations and impact of different system parameters is studied. In addition, performance comparison between QSM, spatial modulation, spatial multiplexing, and single antenna transmission schemes for the same spectral efficiency and in the presence of CCI is presented.

Exploiting Opportunistic Network Coding for Improving Wireless Reliability Against Co-Channel Interference

This paper investigates network coding with full diversity and a high rate for improving the reliability of wireless communications against the co-channel interference. We consider a cellular network composed of two user terminals that are intended to communicate with a common base station (BS), where a two-way relay node is used to assist the bidirectional communications between the users and BS. We propose an opportunistic network coding (ONC) scheme with the two-way relay, called two-way ONC, which operates depending on whether or not the relay node successfully decodes data packets of the user terminals and BS. Closed-form outage probability expressions of the uplink transmission (from users to BS) and downlink transmission (from BS to users) are derived for the proposed two-way ONC scheme in the presence of co-channel interference over Rayleigh fading channels. We also develop the diversity-multiplexing tradeoff (DMT) of the two-way ONC scheme and show that it obtains the full diversity and an increased multiplexing gain , as compared with conventional one-way relay methods. Additionally, numerical outage probability results demonstrate that the proposed two-way ONC scheme outperforms the conventional one-way relay approaches in terms of improving the communication’s reliability against co-channel interference.

Performance Analysis of Opportunistic Scheduling in Dual-Hop Multiuser Underlay Cognitive Network in the Presence of Cochannel Interference

In this paper, the performance of a dual-hop multiuser underlay cognitive network is thoroughly investigated by using a decode-and-forward (DF) protocol at the relay node and employing opportunistic scheduling at the destination users. A practical scenario where cochannel interference signals are present in the system is considered for the investigation. Considering that transmissions are performed over nonidentical Rayleigh fading channels, first, the exact signal-to-interference-plus-noise ratio (SINR) of the network is formulated. Then, the exact equivalent cumulative distribution function (cdf) and the outage probability of the system SINR are derived. An efficient tight approximation is proposed for the per-hop cdfs, and based on this, the closed-form expressions for the error probability and the ergodic capacity are derived. Furthermore, an asymptotic expression for the cdf of the instantaneous SINR is derived, and a simple and general asymptotic expression for the error probability is presented and discussed. Moreover, adaptive power allocation under the total-transmit-power constraint is studied to minimize the asymptotic average error probability. As expected, the results show that optimum power allocation improves the system performance compared with uniform power allocation. Finally, the theoretical analysis is validated by presenting various numerical results and Monte Carlo simulations.

Performance Analysis of a Multi-Hop UCRN With Co-Channel Interference

In this paper, the performance of a multi-hop underlay cognitive radio network (UCRN) is thoroughly assessed. The co-existence of a primary transceiver and co-channel interference (CCI) is considered along with an uplink single-input multiple-output system utilizing selection combining and maximal ratio combining techniques at the receiver nodes. First, the equivalent per-hop signal-to-interference-plus-noise ratio (SINR) for the UCRN is formulated. Second, the exact cumulative distribution function (CDF) and the probability distribution function of the per-hop SINR are derived and discussed. Furthermore, approximate expressions exhibiting reduced complexity for the per hop equivalent CDF are derived to provide more insights. From the resulting CDF, the exact outage performance of the CR network is thoroughly assessed. In addition, mathematical formulas are derived for the average error probability and system ergodic capacity. Finally, the derived analytical expressions are validated by presenting numerical and simulation results for different network parameters. The results show that several factors contribute to the degradation of the system performance, namely, the interference power constraint, the primary transmitter power, and the presence of CCI, especially in the case where the CCI increases linearly with the secondary transmission powers.

Performance Analysis of SNR-Based Decode-and-Forward Opportunistic Relaying in the Presence of Cochannel Interference

Opportunistic relaying (OR) for cooperative communications has been proposed as a technique to provide remarkable gains in multiple-relay cooperative networks. In this paper, we study the effect of cochannel interference (CCI) in the decode-and-forward (DF) OR scheme under independent but not necessarily identically distributed (i.n.i.d) Rayleigh fading channels. In particular, we consider the OR scheme with a signal-to-noise ratio (SNR)-based selection criterion and with the destination-performing maximal ratio combining of the signals from the source and the best relay. We derive approximate but tight closed-form expressions for the outage probability (OP) of the SNR-based OR in the presence of CCI. Moreover, we investigate the asymptotic behavior of the OP of the SNR-based OR. The asymptotic OP for OR with a signal-to-interference-plus-noise ratio (SINR)-based selection criterion is also provided. We examine the diversity orders and coding gains of both criteria under CCI. The result shows that the SNR-based OR is more susceptible to interference at the relays than interference at the destination. We further analytically compare the SNR- and the SINR-based OR schemes. Finally, to verify the analytical results, Monte Carlo simulations are performed, in which more benefits can be gained by using the SINR-based OR when more relays are used.

Closed form expressions for ABER and capacity over EGK fading channel in presence of CCI

ABSTRACTGoal of next generation wireless communication system is to achieve very high data rate. Femto-cell is one of the possibilities to achieve the above target. However, co-channel interference (CCI) is the important concern in femto-cell. This paper presents closed form expressions for average bit error rate (ABER) and capacity for different adaptive schemes under extended generalised-K (EGK) fading channel in the presence of CCI. A novel conditional unified expression (CUE) is derived, which results different conditional error probability and normalised average capacity. Using CUE, a generic expression for ABER is obtained. In addition, closed form expressions for ABER for different modulation schemes under EGK fading channel in presence of CCI are also derived. Further, it is shown that generic ABER expression results into ABER of different modulation schemes. Besides, the closed form expressions of capacity for different adaptive schemes under EGK in presence of CCI are derived. Finally, analytical and simulated results are obtained with excellent agreement.

Performance Characterization of a Hybrid Satellite-Terrestrial System with Co-Channel Interference over Generalized Fading Channels.

The transmission of signals in a hybrid satellite-terrestrial system (HSTS) in the presence of co-channel interference (CCI) is considered in this study. Specifically, we examine the problem of amplify-and-forward (AF)-based relaying in a hybrid satellite-terrestrial link, where the relay node is operating in the presence of a dominant co-channel interferer. It is assumed that direct connection between a source node (satellite) and a destination node (terrestrial receiver) is not available due to masking by obstacles in the surrounding. The destination node is only able to receive signals from the satellite with the help of a relay node located at the ground. In the proposed HSTS, the satellite-relay channel follows the shadowed Rice fading; and the channels of interferer-relay and relay-destination links experience generalized Nakagami-m fading. For the considered AF-based HSTS, we first develop the analytical expression for the moment generating function (MGF) of the overall output signal-to-interference-plus-noise ratio (SINR). Then, based on the derived exact MGF, we derive novel expressions for the average symbol error rate (SER) of the considered HSTS for the following digital modulation techniques: M-ary phase shift keying (M-PSK), M-ary quadrature amplitude modulation (M-QAM) and M-ary pulse amplitude modulation (M-PAM). To significantly reduce the computational complexity for utility in system-level simulations, simple analytical approximation for the exact SER in the high signal-to-noise ratio (SNR) regime is presented to provide key insights. Finally, numerical results and the corresponding analysis are presented to demonstrate the effectiveness of the developed performance evaluation framework and to view the impact of CCI on the considered HSTS under varying channel conditions and with different modulation schemes.

Bit error rate degradation model for time‐delay parameter of co‐channel interference occurring in human body communication

Human body communication (HBC) is a new technology for mobile and wearable devices operating over body area networks. In HBC, the body is used as a medium for transmitting data between devices to replace wired and wireless technologies. This study examines the bit error rate (BER) degradation experienced by HBC systems under the presence of co-channel interference. A degradation model is proposed to estimate the change in BER, and a selective simulation method is proposed to obtain the BER performance with a small exceedance probability and a small number of BER samples.

Packet-Based Energy Efficiency of MIMO Systems With Interference Avoidance Over Frequency-Selective Fading Channels

In this paper, we analyze packet-based energy efficiencies (EE) of battery-powered multiple-input multiple-output (MIMO) mobile radio communications over frequency-selective fading channels in the presence of cochannel interference (CCI). An efficient interference avoidance (IA) technique is proposed that relies on the conveyance of interference statistics derived at the receiver. Using the IA information, which incurs very small overhead, the transmitter selects the subchannels to be used for communications and on these subchannels, channel state information (CSI) derived from time-division duplexing (TDD) operation is applied in linear precoding strategies to minimize transmit energy consumption. The minimum energy solution is conditioned on various factors such as channel coding characteristics, linear precoding beams, interference avoidance schemes, and channel realizations. A method for identifying the transmit power leading to optimization is derived and simulation results show the effectiveness of the techniques over MIMO fading channels with different CCI conditions.

Wireless Information and Power Transfer in Multiway Massive MIMO Relay Networks

Simultaneous wireless information and power transfer techniques for multiway massive multiple-input multiple-output (MIMO) relay networks are investigated. By using two practically viable relay receiver designs, namely 1) the power splitting receiver and 2) the time switching receiver, asymptotic signal-to-interference-plus-noise ratio (SINR) expressions are derived for an unlimited number of antennas at the relay. These asymptotic SINRs are then used to derive asymptotic symmetric sum rate expressions in closed form. Notably, these asymptotic SINRs and sum rates become independent of radio frequency-to-direct current (RF-to-DC) conversion efficiency in the limit of infinitely many relay antennas. Moreover, tight average sum rate approximations are derived in closed form for finitely many relay antennas. The fundamental tradeoff between the harvested energy and the sum rate is quantified for both relay receiver structures. Notably, the detrimental impact of imperfect channel state information (CSI) on the MIMO detector/precoder is investigated, and thereby, the performance degradation caused by pilot contamination, which is the residual interference due to nonorthogonal pilot sequence usage in adjacent/cochannel systems, is quantified. The presence of cochannel interference (CCI) can be exploited to be beneficial for energy harvesting at the relay, and consequently, the asymptotic harvested energy is an increasing function of the number of cochannel interferers. Notably, in the genie-aided perfect CSI case, the detrimental impact of CCI for signal decoding can be cancelled completely whenever the number of relay antennas grows without bound. Nevertheless, the pilot contamination severely degrades the sum rate performance even for infinitely many relay antennas.

Performance Analysis of Amplify-and-Forward Hybrid Satellite-Terrestrial Networks With Cochannel Interference

In this paper, we consider an amplify-and-forward hybrid satellite-terrestrial co-operative network in the presence of cochannel interference (CCI). More specifically, we assume that both the satellite-destination and the satellite-relay links undergo the shadowed-Rician fading and the relay-destination link follows the Nakagami- m fading. By applying the amplify-and-forward (AF) protocol at the terrestrial relay, both the relay and the destination are corrupted by cochannel interference from the terrestrial network. Based on this setup, we first derive the approximate statistical distributions signal-to-interference-plus noise ratio (SINR) and then analyze the system performance. To obtain more insights into the system performance, some asymptotical bit-error rate (BER) results are provided. Moreover, we extend our analysis to a multiple-relay network and analyze the asymptotic performance. Finally, some numerical results are provided to verify our analysis.

Outage Probability for Multi-Hop D2D Communications With Shortest Path Routing

In this letter, we provide a tractable theoretical framework for analysing the performance of device-to-device (D2D) communications in the presence of co-channel interference from other D2D and conventional cellular (CC) transmissions. In particular, we consider multi-hop D2D using the shortest-path-routing (SPR) algorithm in both the uplink (UL) and the downlink (DL) channels. Closed-form expressions for the number of hops and the outage probability are presented. Our analytical and numerical results both show that while the D2D links are reasonably reliable (outage probability <; 5%), they can severely degrade the performance of CC transmissions (outage probability > 25%). Accordingly, we exploit and provide insights into the trade-off between D2D and CC transmission reliability.

Performance estimation for indoor wireless systems using FDTD method

A three-dimensional implementation of the finite-difference time-domain method is used to estimate the down-link outage probability of a direct-sequence code division multiple access system operating in a multi-storey office building in the presence of co-channel interference. The numerical analysis is supported by experimental measurements and good agreement is found for the outage probability. Both simulation and measured results indicate that vertically aligned co-channel base stations have lower outage than a vertically staggered configuration, which is explained by examining the correlation between the desired and interfering signals.

Outage Equivalence of Opportunistic Relaying and Selection Cooperation in Presence of Co-Channel Interference

In this paper, we investigate two different relay selection schemes, opportunistic relaying (OR) and selection cooperation (SC), for decode-and-forward (DF)-based relay networks consisting of a source, multiple relays, and a destination in the presence of multiple co-channel interferers, where each terminal has a single antenna and operates in a half-duplex mode. For the network, we first extend the conventional OR and SC to relay networks with the direct-path and multiple co-channel interferers, and obtain the exact and closed-form outage probability of the OR. Then, we show that the SC is equivalent to the OR in terms of outage performance for relay networks with the direct-path and multiple co-channel interferers. Finally, we show that the SC and OR are outage-optimal under the aggregate power consumption constraint at the relays for relay networks with the direct-path and multiple co-channel interferers.

Optimum Combining in Dual-Hop AF Relaying for Maximum Spectral Efficiency in the Presence of Co-Channel Interference

The performance of optimum combining (OC) in amplify-and-forward (AF) relaying systems in the presence of co-channel interference (CCI) is analyzed using a tight approximation for the signal-to-interference-plus-noise ratio (SINR) at the destination. Two types of relaying protocols are studied, all-relay transmission with OC and best-relay transmission with OC. When CCI is present only at the destination, both relaying protocols achieve diversity gains up to $M$ when interferer powers are scaled with the source and the relay powers, where $M$ is the number of relays. Best-relay transmission with OC maximizes the spectral efficiency as each communication consumes only two time slots.

Performance Analysis of Multihop AF Relaying Systems in the Presence of Cochannel Interferences

This paper investigates the performance of N-hop ([Formula: see text]) amplify-and-forward (AF) relaying systems with both relays and the destination subject to independent and not necessarily identically distributed multiple cochannel interferences (CCIs). Based on a new class of upper bound of the equivalent signal-to-interference ratio (SIR) which is the harmonic mean of the minimum of the first [Formula: see text] hop SIRs and the minimum of the remaining [Formula: see text] hop SIRs, new approximate closed-form expressions of the outage probability and the ergodic capacity are derived. Furthermore, we derive the asymptotic expression of outage probability which accurately reveals the achievable coding gain and diversity gain. Finally, numerical results validate the correctness of the derived expressions.

Performance analysis of SSC diversity reception over η–μ fading channel in the presence of CCI

The aim of this paper is to study the performance of a switch-and-stay combining (SSC) receiver, operating in the presence of η–μ fading and co-channel interference (CCI). The analysis will incorporate both cases when the receiver branches are independent and when a correlation arises between them. Infinite-series expressions will be presented for the probability density function (PDF) and cumulative distribution function (CDF) of the SSC output signal-to-interference ratio (SIR). Further, capitalising on them, standard wireless performance measures, outage probability (OP) and average bit error probability (ABER) will be determined and discussed in the function of various system parameters, including fading severity, observed threshold and input SIR unbalance.

Performance Analysis of Cooperative Vehicular Systems with Co-channel Interference Over Cascaded Nakagami-m Fading Channels

In this paper, we investigate a dual-hop decode-and-forward (DF) relaying vehicular system in the presence of co-channel interference, in which source, relay and destination terminals are composed ...