Showing papers on "Co-channel interference published in 2019"
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TL;DR: This paper provides important design guidelines for the deployment of multiple UAVs in the presence of co-channel interference and reveals that the SINR threshold, the separation distance, and the number of Uavs and their formations should be carefully selected to achieve the maximum coverage area inside and to reduce the unnecessary expansion outside the target area.
Abstract: The use of the unmanned aerial vehicle (UAV) as the aerial base stations can provide wireless communication services in the form of UAV-based small cells (USCs). Thus, the major design challenge that needs to be addressed is the coverage maximization of such USCs in the presence of co-channel interference generated by multiple UAVs operating within a specific target area. Consequently, the efficient deployment strategy is imperative for USCs while optimizing the coverage area performance to compensate for the impact of interference. To this end, this paper presents a coordinated multi-UAV strategy in two scenarios. In the first scenario, symmetric placement of UAVs is assumed at a common optimal altitude and transmit power. In the second scenario, asymmetric deployment of UAVs with different altitudes and transmit powers is assumed. Then, the coverage area performance is investigated as a function of the separation distance between UAVs that are deployed in a certain geographical area to satisfy a target signal-to-interference-plus-noise ratio (SINR) at the cell boundary. Finally, the system-level performance of a boundary user is studied in terms of the coverage probability. The numerical results unveil that the SINR threshold, the separation distance, and the number of UAVs and their formations should be carefully selected to achieve the maximum coverage area inside and to reduce the unnecessary expansion outside the target area. Thus, this paper provides important design guidelines for the deployment of multiple UAVs in the presence of co-channel interference.
49 citations
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TL;DR: The simulation results show that FD systems with the proposed CCI-EC achieve near-optimal achievable SE and outperform the conventional HD systems and FD systems without CCI -EC in terms of the achievable SE.
Abstract: In-band full-duplex (FD) systems have been widely studied because they can double the spectral efficiency (SE) compared with conventional half-duplex (HD) systems, theoretically. However, inherent interference caused by both self-interference (SI) and co-channel interference (CCI) makes FD systems to achieve theoretical SE hard. In this paper, we propose a CCI estimation and cancellation (CCI-EC) protocol for the FD systems to overcome performance degradation due to CCI. We suggest to use a coherence channel block for two phases: CCI channel is estimated at a downlink (DL) user through uplink (UL) pilot signals in the first phase, then a base station (BS) and a UL user transmit their data simultaneously in the second phase, in which a DL user cancels interfering signals from a UL user by utilizing the estimated CCI channel information. We analyze the achievable SE of FD systems with CCI-EC and formulate a resource allocation problem to maximize it, where resource includes pilot and data transmission time, and transmit power of a BS and a UL user. A closed-form optimal power allocation for UL pilot and data transmissions and a suboptimal power allocation for DL data transmission are provided. The simulation results show that FD systems with the proposed CCI-EC achieve near-optimal achievable SE and outperform the conventional HD systems and FD systems without CCI-EC in terms of the achievable SE. Especially, the SE gain achieved by the proposed CCI-EC protocol in FD systems is remarkable under severe interference environment.
24 citations
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TL;DR: In this article, the performance of multiuser-radio frequency/free space optics (RF/FSO) two-way relay network in the presence of interference is investigated.
Abstract: In this letter, the performance of multiuser-radio frequency/free space optics (RF/FSO) two-way relay network in the presence of interference is investigated. The FSO link accounts for pointing errors and both types of detection techniques, i.e., intensity modulation/direct detection as well as coherent demodulation, which is modeled as double generalized gamma (D-GG) turbulence channel. On the other hand, the multiple users on the RF link are assumed to undergo Nakagami- $m$ fading. Multiple co-channel interferers (CCIs) which corrupt the signal at relay node are modeled using Nakagami- $m$ distribution. Specifically, the exact closed-form expressions for the outage probability (OP) of the overall system are derived. Moreover, the closed form expression for the achievable sum-rate (ASR) of the considered system is presented. In order to simplify the results, the asymptotic approximations of the OP and ASR are derived in terms of elementary functions. The results presented in the letter are validated by the Monte Carlo simulations.
20 citations
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TL;DR: An optimization problem for power allocation is formulated and solved to improve the secrecy performance of the network by minimizing the asymptotic SOP for both Col and Non-Col cases.
Abstract: This paper investigates the secrecy performance of a multiuser system that utilizes transmit antenna selection scheme at the base station and adopts threshold-based selection diversity opportunistic scheduling over legitimate nodes. The legitimate transmission suffers from the presence of noncolluding (Non-Col) and colluding (Col) multiple passive eavesdroppers. Both the legitimate and eavesdropping nodes are assumed to suffer from co-channel interference (CCI) signals from independent channels that follow Rayleigh fading. Closed-form expressions for the probability density functions and cumulative density functions of the end-to-end signal-to-interference-plus-noise ratio for both eavesdropping scenarios in the presence of CCI signals are derived. In addition, closed-form expressions for the network secrecy outage probability (SOP) for Non-Col/Col scenarios are derived. At the high signal-to-noise ratio values, closed-form expressions for the asymptotic secrecy outage probabilities are obtained. Following this obtained asymptotic analysis, an optimization problem for power allocation is formulated and solved to improve the secrecy performance of the network by minimizing the asymptotic SOP for both Col and Non-Col cases. The derived analytical expressions are then validated using both simulations and numerical results.
17 citations
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TL;DR: Two novel interference-aware scheduling algorithms for a DVB-RCS2 return uplink are presented and designed on the basis to be executed in real time on a fixed SuperFrame period basis.
Abstract: Very high throughput satellites (VHTS) are the new trend in satellite communications systems in order to satisfy the increasing demand for both higher throughput and ubiquitous connectivity. Implementing an IP interactive network over a VHTS would enable the satellite to compete with terrestrial networks by offering ubiquitous added value services for end-user traffic. Even so, the simulations presented in this paper show that a 30% of throughput can be lost due to co-channel interferences. In existing interactive satellite networks such as REDSAT or AmerHis, the return uplink transmissions are inherently benefited from the MF-TDMA scheduling to mitigate the co-channel interferences present in VHTS. In such networks dynamic resource assignation (DAMA) is executed at each SuperFrame period (<100 ms). Therefore, any feasible optimization on the scheduling shall be performed in real time. In this paper, two parallel problems are faced at the same time: co-channel interference mitigation and real time scheduling. In particular, two novel interference-aware scheduling algorithms for a DVB-RCS2 return uplink are presented. Despite other previous works, the proposed algorithms are designed on the basis to be executed in real time on a fixed SuperFrame period basis. The performance assessment of the proposed algorithms is carried out through system-level simulations based on realistic satellite scenarios and interactive traffic models using DAMA in real time.
14 citations
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24 Jun 2019TL;DR: This paper analyzes various interference scenarios that may occur on the uplink and downlink of terrestrial IoT and satellite IoT, establishes a global dynamic model of interference volume, and obtains the dynamic distribution of global interference of low-orbit satellite IoT through simulation.
Abstract: In recent years, the Internet of Things (IoT) technology has shown a good momentum of development and has been widely used in various fields of society. Satellite IoT, as an important complement and extension of the ground IoT, provides services in areas where oceanic and desert areas cannot build terrestrial IoT base stations. However, due to limited spectrum resources, spectrum sharing between terrestrial IoT and satellite IoT is likely to be required, which will inevitably lead to uplink and downlink co-channel interference between systems. This paper analyzes various interference scenarios that may occur on the uplink and downlink of terrestrial IoT and satellite IoT. Then, we establishes a global dynamic model of interference volume, and obtains the dynamic distribution of global interference of low-orbit satellite IoT through simulation. Finally, the paper uses the low-orbit satellite IoT global interference scenarios, interference distribution model and interference analysis model to obtain the dynamic analysis of the global uplink and downlink interference of the low-orbit satellite IoT, and uses the interference analysis results to give suggestions for the deployment of Low-orbit Satellite IoT.
13 citations
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TL;DR: Simulation results show that, in the interference-effected system, when the average signal-to-noise ratio increases, system performance enhances first and then remains unchanged, which implies the system performance is limited by the numbers and power of CCIs.
Abstract: In this paper, the performance of a two-way mixed radio frequency/free space optical (RF/FSO) relaying system in the presence of co-channel interference (CCI) is investigated. The RF links are modeled as Nakagami-m distribution, and FSO links adopt Gamma-Gamma turbulence model. To improve spectral efficiency, relay exchanges the information between two terminals in three phases via RF and FSO links. Meanwhile, CCIs are considered at both relay and destination. Novel closed-form upper bounds expressions for the signal to interference plus noise ratios are derived, based on that lower bounds outage probability, average bit error rate, and outage capacity are further presented for both RF/FSO and FSO/RF links. Then, asymptotic expressions are provided to predict the diversity order. Additionally, the effect of various parameters on system performance, such as interference numbers and power, are investigated and compared including interference-free condition. Simulation results show that, in the interference-effected system, when the average signal-to-noise ratio increases, system performance enhances first and then remains unchanged. This phenomenon does not occur in the interference-free system, which implies the system performance is limited by the numbers and power of CCIs. Moreover, the effect of pointing errors on system performance is further investigated.
12 citations
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TL;DR: This paper investigates power beacon assisted (PB) energy harvesting in half-duplex (HD) communication network under co-channel Interferer over Rayleigh fading environment and investigates the model system with the time switching (TS) protocol.
Abstract: In this time, energy efficiency (EE), measured in bits per Watt, has been considered as an important emerging metric in energy-constrained wireless communication networks because of their energy shortage. In this paper, we investigate power beacon assisted (PB) energy harvesting (EH) in half-duplex (HD) communication network under co-channel Interferer over Rayleigh fading environment. In this work, we investigate the model system with the time switching (TS) protocol. Firstly, the exact and asymptotic form expressions of the outage probability (OP) are analyzed and derived. Then the system EE is investigated and the influence of the primary system parameters on the system performance. Finally, we verify the correctness of the analytical expressions using Monte Carlo simulation. Finally, we can state that the simulation and analytical results are the same.
12 citations
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TL;DR: Simulations demonstrate that, similar to the 4G long term evolution, the ATSC 3.0 co-channel assignment could be reduced to two times the service coverage radius, which means an improvement of the spectrum efficiency by up to four times in comparison with today’s system.
Abstract: In addition to the traditional TDM/FDM, the advanced television systems committee (ATSC) 3.0 next generation digital TV standard has adopted state-of-the-art coding and modulation, as well as the new layered division multiplexing (LDM) technology. The ATSC 3.0 system is able to provide higher data throughput, more robust reception, better spectrum efficiency, and flexible service combinations in one RF channel with different robustness and reception conditions. Due to the adoption of a two-layer LDM, the coverage for ATSC 3.0 is very different from the legacy one-transmitter-one-coverage ATSC 1.0 system. With the new enabling technologies, the ATSC 3.0 can greatly increase the coverage/service areas, reduce the distance between co-channel assignments, and introduce local program insertion and targeted advertisement. This paper addresses the ATSC 3.0 coverage and co-channel interference issues, by using the two-layer LDM technology with different operating parameters. Simulations demonstrate that, similar to the 4G long term evolution, the ATSC 3.0 co-channel assignment could be reduced to two times the service coverage radius. This means an improvement of the spectrum efficiency by up to four times in comparison with today’s system. It is also proved through simulations that significant TV program gains can be obtained with this new system. The deployment of single frequency networks can further improve the coverage and reduce the interference.
10 citations
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01 Oct 2019
TL;DR: To increase system capacity in the full bandwidth beam hopping satellite systems, a resource allocation algorithm based on spatial clustering is proposed, which increases the system capacity by 25.1%, and the total interference power of the system is far less than the noise power, which meets the interference control requirements.
Abstract: To increase system capacity in the full bandwidth beam hopping satellite systems, a resource allocation algorithm based on spatial clustering is proposed. According to the proportion of the required capacity to the available resources, the algorithm allocates corresponding amount of timeslots to each beam, increasing the system capacity on the premise of satisfying relative fairness. A distance threshold is calculated that when the distance between beams is greater than the threshold, the influence of interference on signal quality can be ignored. Thus, controlling the distance between beams illuminated simultaneously to be greater than the threshold can avoid the interference. Numerical results show that compared with the traditional multibeam system, this algorithm increases the system capacity by 25.1%, and the total interference power of the system is far less than the noise power, which meets the interference control requirements.
10 citations
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TL;DR: This paper analyzes the secrecy outage probability and computation overhead of a multi-user multi-eavesdropper wireless system which is composed of one cluster head transmitting to multiple users, while multiple eavesdroppers attempt to tap the transmission from CH to several users in the presence of co-channel interference (CCI).
Abstract: In this paper, we analyze the secrecy outage probability and computation overhead of a multi-user multi-eavesdropper wireless system which is composed of one cluster head (CH) transmitting to multiple users, while multiple eavesdroppers attempt to tap the transmission from CH to multiple users in the presence of co-channel interference (CCI). To achieve high security and low computation overhead, we present two multi-user scheduling schemes, namely, the switch-and-examine combining with post-selection user scheduling (SECpsUS) scheme and the selection combining-based user scheduling (SCbUS) scheme. For the purpose of comparison, the conventional round-robin scheduling (RRS) is also considered as a benchmark scheme. Furthermore, we derive closed-form secrecy outage probability expressions and analyze computation overheads for the conventional RRS, SCbUS, and SECpsUS schemes. Numerical results and Monte Carlo simulations are provided to verify the correctness of our theoretical secrecy outage analysis and to demonstrate the effect of CCI on the system performance. It is shown that the SECpsUS and SCbUS schemes outperform the conventional RRS scheme in terms of their secrecy outage probabilities, where SCbUS achieves the best secrecy outage performance but at cost of the highest computation overhead, while the conventional RRS scheme has no computation overhead with the worst secrecy performance. Moreover, a flexible tradeoff between the secrecy outage performance and computation overhead can be achieved by the proposed SECpsUS scheme by adjusting a so-called switching threshold. In addition, as the number of users increases, the secrecy outage performance of the SECpsUS and SCbUS is improved significantly, whereas no secrecy benefit is achieved by the conventional RRS scheme.
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TL;DR: The main contribution of this paper is to derive exact closed-form expressions of outage probability, probability of successful and secure communication, intercept probability, and average number of time slots used by the source over Rayleigh fading channel under the joint impact of co-channel interference and hardware impairments.
Abstract: In this paper, we propose a rateless codes-based communication protocol to provide security for wireless systems. In the proposed protocol, a source uses the transmit antenna selection (TAS) technique to transmit Fountain-encoded packets to a destination in presence of an eavesdropper. Moreover, a cooperative jammer node harvests energy from radio frequency (RF) signals of the source and the interference sources to generate jamming noises on the eavesdropper. The data transmission terminates as soon as the destination can receive a sufficient number of the encoded packets for decoding the original data of the source. To obtain secure communication, the destination must receive sufficient encoded packets before the eavesdropper. The combination of the TAS and harvest-to-jam techniques obtains the security and efficient energy via reducing the number of the data transmission, increasing the quality of the data channel, decreasing the quality of the eavesdropping channel, and supporting the energy for the jammer. The main contribution of this paper is to derive exact closed-form expressions of outage probability (OP), probability of successful and secure communication (SS), intercept probability (IP) and average number of time slots used by the source over Rayleigh fading channel under the joint impact of co-channel interference and hardware impairments. Then, Monte Carlo simulations are presented to verify the theoretical results.
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TL;DR: In this study, a two-hop decode-and-forward incremental relaying over Rayleigh fading channels is assessed taking into account the existence of multiple non-identical interferers close to the destination.
Abstract: Incremental relaying was initially presented so as to adjust for the shortages or limitations related to the usual cooperative methods, specifically, the fixed relaying methods in which the relay node assists the source node in transmitting the signals belonging to the destination independent of the channel status. Matter of fact, the adaptive relaying methods related to the cooperative diversity networks have attracted current researchers’ attention as of being capable of offering an efficient way in assigning the channel expedients when required. In this study, a two-hop decode-and-forward incremental relaying over Rayleigh fading channels is assessed taking into account the existence of multiple non-identical interferers close to the destination. Interestingly, investigating the non-identical interferers case instead of identical ones, like what are published in the literature, is extremely challenging as it refers to a more generalised case. Interestingly, the performance of the system is degraded due to co-channel interference. To this end, tight closed-form expressions of the bit error rate and outage probability are ultimately obtained. Analytical and simulation results are introduced to consolidate the assumptions considered.
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TL;DR: To combat interference with low overhead, this work proposes a generic interference-aware resource management framework based on joint spatial division and multiplexing (JSDM).
Abstract: By providing interactive broadband services to geographical areas underserved by terrestrial infrastructure, multi-beam satellite systems play a central role in future wireless communications. Targeting the terabit throughput requirements in satellite communications, we introduce a cognitive radio-based high-throughput satellite (HTS) system architecture where full frequency reuse is employed among beams. Moreover, by analyzing the characteristics of the considered architecture, we discuss the design challenges of radio resource management in cognitive HTS systems exposed to both intra-system and inter-system co-channel interference. Furthermore, to combat interference with low overhead, we propose a generic interference-aware resource management framework based on joint spatial division and multiplexing (JSDM). Under this framework, user grouping along with two-stage precoding is studied to achieve substantial improvement in the overall system throughput. Finally, some future research directions and challenges are also given.
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TL;DR: The use of maximal ratio transmission (MRT) is investigated to achieve high reliability while requiring low receiver complexity for the relay and the impact of channel estimation errors on the performance is included.
Abstract: Amplify-and-forward (AF) two-way relay networks (TWRNs) have become popular to provide spectrally efficient communication when range extension or energy efficiency is needed by utilizing a simple relay. However, their performance can be significantly degraded in practice due to co-channel interference (CCI) which is increasing due to growing number of wireless devices and recent cognitive and non-orthogonal multiple access techniques. With the motivation of improving the performance of AF-TWRNs, the use of maximal ratio transmission (MRT) is investigated to achieve high reliability while requiring low receiver complexity for the relay. First, the signal-to-interference-plus-noise ratio (SINR) expression is formulated and upper bounded. Then, tight lower bound expressions of outage probability (OP), sum symbol error rate (SSER), and upper bound ergodic sum rate (ESR) for each source and for the overall system are obtained. Besides, array and diversity gains are provided after deriving the asymptotic expressions of OP and SSER at high signal-to-noise ratio (SNR). Furthermore, the impact of channel estimation errors on the performance is also included. Finally, Monte Carlo simulation results which corroborate our theoretical findings are illustrated.
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TL;DR: This paper investigates the secrecy outage performance of the decode-and-forward cognitive relay network with the existence of the co-channel interference, where all nodes are equipped with single antenna and all channels experience Rayleigh fading channels.
Abstract: In this paper, we investigate the secrecy outage performance of the decode-and-forward cognitive relay network with the existence of the co-channel interference, where all nodes are equipped with single antenna and all channels experience Rayleigh fading channels, which are also independent non-identical distribution (i.n.i.d). We also consider the multiple user selection scheme and the single eavesdropper, which could wiretap the information at each hop. There is no evidence of the direct links from the source to the destinations because of the bad conditions. To evaluate the system secrecy performance, we derive the closed form expressions of the secrecy outage probabilities, and the Monte Carlo simulations are also presented to validate the accuracy of the theoretical analysis.
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TL;DR: This paper evaluates outage probability of a cluster-based multi-hop protocol operating on an underlay cognitive radio (CR) mode and finds that the CCI caused by the primary operations significantly impacts on the outage performance of the secondary network.
Abstract: In this paper, we evaluate outage probability (OP) of a cluster-based multi-hop protocol operating on an underlay cognitive radio (CR) mode. The primary network consists of multiple independent transmit/receive pairs, and the primary transmitters seriously cause co-channel interference (CCI) to the secondary receivers. To improve the outage performance for the secondary network under the joint impact of the CCI and hardware imperfection, we employ the best relay selection at each hop. Moreover, the destination is equipped with multiple antennas and uses the selection combining (SC) technique to enhance the reliability of the data transmission at the last hop. For performance evaluation, we first derive an exact formula of OP for the primary network which is used to calculate the transmit power of the secondary transmitters. Next, an exact closed-form expression of the end-to-end OP for the secondary network is derived over Rayleigh fading channels. We then perform Monte-Carlo simulations to validate the derivations. The results present that the CCI caused by the primary operations significantly impacts on the outage performance of the secondary network.
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TL;DR: This study investigates the security and reliability trade-off (SRT) performance of a multiuser wireless network, where an eavesdropper attempts to overhear the confidential transmissions between a base station and multiple users under the impact of co-channel interference and proposes two joint user and jammer selection schemes.
Abstract: In this study, the authors investigate the security and reliability trade-off (SRT) performance of a multiuser wireless network, where an eavesdropper attempts to overhear the confidential transmissions between a base station and multiple users under the impact of co-channel interference. To enhance the SRT performance of the network, the authors propose two joint user and jammer selection schemes, namely the joint optimal user and random jammer selection (JOU-RJS) scheme and the joint optimal user and optimal jammer selection (JOU-OJS) scheme. For SRT performance comparison purposes, the traditional multiuser scheduling (TMUS) scheme is also considered. The authors derive closed-form outage and intercept probability expressions for the JOU-RJS and JOUOJS schemes. Simulation results show that the SRTs of both JOU-RJS and JOU-OJS schemes are better than that of the TMUS scheme, where JOU-OJS achieves the best SRT performance. Additionally, this study also shows that an expected outage or intercept probability of the TMUS, JOU-RJS, and JOU-OJS schemes can be achieved by giving an appropriate overall rate. Finally, the sum of the outage and intercept probability can be minimised through an optimal power allocation between the selected user and friendly jammer for the proposed JOU-RJS and JOU-OJS.
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20 May 2019TL;DR: Overall interference levels was observed to be approximately 20 dBm smaller at 300 GHz than at 60 GHz and angular dependency of interfering power was much more forward oriented for 300 GHz frequency.
Abstract: Results at mm wave frequencies have shown that it is important to evaluate co-channel interference between directional beams that cross each other. Terahertz frequency bands, especially around 300 GHz, has been considered for future wireless communications. As far as we know, no work has considered the rain induced interference at THz frequencies. In this work, we evaluate the rain induced interference at 300 GHz. Results are calculated also at 60 GHz in order to make a comparison. We combined bistatic radar equation, first order multiple scattering approximation and full Mie scattering calculations to existing drop size distribution models to estimate interference due to rain. Considered effective path lengths between transmitter and receiver are 100 m and 500 m and the effect of selected drop size distribution is studied. Overall interference levels was observed to be approximately 20 dBm smaller at 300 GHz than at 60 GHz and angular dependency of interfering power was much more forward oriented for 300 GHz frequency. The results show that rain induces interference has significantly different behaviour at THz as compared to lower frequencies.
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TL;DR: By exploiting circulant properties of the channel frequency response (CFR) autocorrelation matrix, an efficient low complexity linear-minimum-mean-square-error (LMMSE) estimator is proposed that applies an expectation–maximization (EM) iterative process to reduce the computational complexity significantly.
Abstract: In time-selective fading channel, the Alamouti orthogonality principle is lost due to the variation of channel from symbol-to-symbol in space–time block-coded orthogonal frequency division multiple...
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01 Dec 2019TL;DR: It is shown that co-channel interference robustness of direct-detection receivers is improved by using Binary Phase Shift Keying (BPSK) Barker code modulated Surface Acoustic Wave (SAW) correlator as a prior stage to the RF envelope detector.
Abstract: Using direct-detection architecture in Radio Frequency (RF) receivers allows for ultra-low power dissipation and is often used in Wake-Up receivers. Unfortunately direct-detection receivers suffer from high sensitivity to co-channel interference which reduces the communication performance and reliability. In this paper, it is shown that co-channel interference robustness of direct-detection receivers is improved by using Binary Phase Shift Keying (BPSK) Barker code modulated Surface Acoustic Wave (SAW) correlator as a prior stage to the RF envelope detector. Replacing the band select filter with SAW correlator does not result in higher receiver hardware cost. In our receiver, the SAW correlator functions as a passive signal processor, providing gain for a BPSK Barker code modulated signal, while suppressing in-band interferers. This improves the co-channel interference robustness of the direct-detection receiver while preserving its advantage of power efficiency. The concept is verified by means of a direct-detection receiver with discrete components on an RF PCB including an SAW Barker Code correlator at a center frequency of 2.44 GHz fabricated on Lithium Niobate substrate. Measurements with WiFi signals demonstrate that the interference robustness is improved by more than 10 dB compared to a conventional direct-detection receiver.
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TL;DR: Game theoretic results are exploited to investigate the intercell interference management in SCFD-based cellular networks under infeasible QoS requirements and a computationally efficient distributed algorithm, which realizes best effort and fair wireless services is designed.
Abstract: Several emerging mobile applications and services (eg, autonomous cars) require higher wireless throughput than ever before This demand stresses the need for investigating novel methods that have the potential to dramatically increase the spectral efficiency (SE) of wireless systems An evolving approach is the Single-channel full duplex (SCFD) communication where each node may simultaneously receive and transmit over the same frequency channel, and, hence, this could potentially double the current SE figures In an earlier research work, we derived a model of the signal to interference plus noise ratio (SINR) in an SCFD-based cellular system with imperfect self interference cancellation, and investigated interference management under feasible QoS requirements In this paper, game theoretic results are exploited to investigate the intercell interference management in SCFD-based cellular networks under infeasible QoS requirements The investigation starts with a game formulation that captures two different cases Then, the existence and uniqueness of the Nash equilibrium point are established After that, a computationally efficient distributed algorithm, which realizes best effort and fair wireless services, is designed The merit of this scheme is that, when the QoS requirements are feasible, they will be achieved with minimum energy consumption Results of extensive simulation experiments are presented to show the effectiveness of the proposed schemes
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01 Oct 2019
TL;DR: An analytical study on the performance of the non-orthogonal multiple access (NOMA) scheme in a satellite system, where the users are impaired by multiple co-channel interferences (CCI).
Abstract: In this paper, we present an analytical study on the performance of the non-orthogonal multiple access (NOMA) scheme in a satellite system, where the users are impaired by multiple co-channel interferences (CCI). Theoretical expressions for the ergodic capacity, exact outage probability and asymptotic are derived. Numerical results are provided to demonstrate the theoretical results and indicate the effects of CCI, power allocation and channel parameters on the system performance.
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TL;DR: This work proposes a novel heuristic approach for better channel utilisation for these services, blending the idea of cognitive radio and multi-channel lending/borrowing, and shows that among the new call and handoff services, the latter are given priority to serve.
Abstract: Radio channel allocation is broadly studied in the framework of cellular networks. Channels are scarce resources and to be utilised judiciously by the cells of the network. During the course of channel allocation, channels are normally lent/borrowed to the neighbour cells. Most of the available channel allocation techniques apply only single lending/borrowing. With the emergence of cognitive radio, it has now become possible to utilise the channels opportunistically. Availing the channels are the services which are normally categorised into real-time and non-real-time services. Of these, real-time services are given more priority to serve over the non-real-time services. Further, among the new call and handoff services, the latter are given priority to serve. This work proposes a novel heuristic approach for better channel utilisation for these services, blending the idea of cognitive radio and multi-channel lending/borrowing. The performance study, of the proposed model, is done by simulation which reveals the effective channel utilisation in terms of blocked and dropped services.
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13 Jun 2019
TL;DR: This paper evaluates outage probability (OP) of a cooperative underlay cognitive radio network in the presence of a passive secondary eavesdropper under joint impacts of limited interference from a primary network and hardware impairments.
Abstract: This paper evaluates outage probability (OP) of a cooperative underlay cognitive radio network in the presence of a passive secondary eavesdropper under joint impacts of limited interference from a primary network and hardware impairments. With intercept probability constraint required for the eavesdropper and interference constraint given by a primary receiver, we derive closed-form expressions of transmit power for the secondary transmitters, including source and relays, only relying on the knowledge of statistical channel state information (CSI). Then, a relay selection method is used in the cooperative phase to enhance the OP performance of the considered protocol. For performance evaluation, we derive an exact closed-form expression of OP over Rayleigh fading channel. Finally, we perform Monte Carlo simulations to verify the derived formulas.
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01 Jun 2019TL;DR: The closed-form of average bit error probability (ABEP) for BPSK and M-ary QAM modulations with OFDM-IM are derived in the absence and presence of co-channel interference (CCI) over composite Nakagami-m and Gamma (NG) shadowing channel.
Abstract: Orthogonal frequency division multiplexing with Index Modulation (OFDM-IM) has been used to transmit extra bits by indexing subcarriers using the ON-OFF keying modulation. In this paper, the closed-form of average bit error probability (ABEP) for BPSK and M-ary QAM modulations with OFDM-IM are derived in the absence and presence of co-channel interference (CCI) over composite Nakagami-m and Gamma (NG) shadowing channel. Simple closed-form expressions are introduced by using the Meijer G function. The theoretical results are validated through comparisons with existing research studies.
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01 Dec 2019TL;DR: The users' channel quality is taken into consideration to dynamically allocate resources to users in Li-Fi network and the proposed scheme can achieve a high improvement in total system spectral efficiency and increase in average data rate per user comparable to other scheduling algorithms, i.e., round robin and proportional fairness scheduling.
Abstract: 5G networks occupies a high interest recently because it enables internet of things applications. One of these networks is light fidelity (Li-Fi) technology that attracts high attention nowadays in wireless communication field. Because it has a large swath of spectrum hence the ability to provide high end user data rate up to multiple Gbps. However, Li-Fi suffers from big issues such as co-channel interference (CCI) between users. This problem highly degrades Li-Fi performance. To overcome on this challenge, an efficient resource allocation between users is needed to obtain optimum usage of available system spectrum. In this paper, the users' channel quality is taken into consideration to dynamically allocate resources to users in Li-Fi network. Based on this criterion, the network guarantees efficient spectrum distribution among users without wasting resources for users with bad channel conditions thus improving the system performance. Hence, the proposed scheme can achieve a high improvement in total system spectral efficiency and increase in average data rate per user comparable to other scheduling algorithms, i.e., round robin and proportional fairness scheduling, as it will be discussed in numerical simulation.
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TL;DR: Numerical results demonstrate the existence of OP and SER floors in the presence of CCI, which implies system performance is dominant by RF links, and interference is the main factor affecting the system performance.
Abstract: In this study, the performance of the mixed radio-frequency (RF)/free-space optical (FSO) system with co-channel interference (CCI) is investigated. The RF links are modelled as Rayleigh fading, whereas FSO links follow M-distribution with pointing errors. Assume the amplify-and-forward relay is corrupted by multiple CCIs, and both fixed and variable gain relay schemes are considered. Novel expressions for the end-to-end outage probability (OP), symbol error rate (SER) and outage capacity in different cases are presented and analysed. Numerical results demonstrate the existence of OP and SER floors in the presence of CCIs, which implies system performance is dominant by RF links, and interference is the main factor affecting the system performance. Additionally, the fixed gain scheme provides a performance enhancement compared with the variable gain scheme in the authors' system.
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03 Jan 2019
TL;DR: In this paper, an apparatus and digital signal processing means are disclosed for excision of co-channel interference from signals received in crowded or hostile environments using spatial/polarization diverse arrays, which reliably and rapidly identifies communication signals with transmitted features that are self-coherent over known framing intervals due to known attributes of the communication network.
Abstract: An apparatus and digital signal processing means are disclosed for excision of co-channel interference from signals received in crowded or hostile environments using spatial/polarization diverse arrays, which reliably and rapidly identifies communication signals with transmitted features that are self-coherent over known framing intervals due to known attributes of the communication network, and exploits those features to develop diversity combining weights that substantively excise that co-channel interference from those communication signals, based on differing diversity signature, timing offset, and carrier offset between the network signals and the co-channel interferes In one embodiment, the co-channel interference excision is performed in an applique that can be implemented without coordination with a network transceiver
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TL;DR: A global framework analysis of a dual-hop mixed radio frequency (RF)/free space optical (FSO) system with multiple branches/relays wherein the first and second hops, respectively, consist of RF and FSO channels and derives the asymptotic high SNR to unpack valuable engineering insights of the system performance.
Abstract: In this paper, we provide a global framework analysis of a dual-hop mixed Radio Frequency (RF)/Free Space Optical (FSO) system with multiple branches/relays wherein the first and second hops, respectively, consist of RF and FSO channels. To cover various cases of fading, we propose generalized channels' models for RF and FSO links that follow the Nakagami-m and the Double Generalized Gamma (DGG) distributions, respectively. Moreover, we suggest Channel State Information (CSI)-assisted relaying or variable relaying gain based Amplifiy-and-Forward (AF) amplification. Partial relay selection with outdated CSI is assumed as a relay selection protocol based on the knowledge of the RF CSI. In order to derive the end-to-end Signal-to-Interference-plus-Noise Ratio (SINR) statistics such as the Cumulative Distribution Function (CDF), the Probability Density Function (PDF), the higher order moments, the amount of fading and the Moment Generating Function (MGF), the numerical values of the fading severity parameters are only valid for integer values. Based on these statistics, we derive closed-forms of the outage probability, the bit error probability, the ergodic capacity and the outage capacity in terms of Meijer-G, univariate, bivariate and trivariate Fox-H functions. Capitalizing on these expressions, we derive the asymptotic high SNR to unpack valuable engineering insights of the system performance. Monte Carlo simulation is used to confirm the analytical expressions.