Showing papers on "Co-channel interference published in 2021"

Reconfigurable Intelligent Surface for Mixed FSO-RF Systems With Co-Channel Interference

Abstract: Reconfigurable intelligent surface (RIS) is an emerging technology that can achieve reconfigurable radio propagation environments for beyond 5G/6G wireless systems by smartly tuning the signal reflection via a large number of low-cost passive reflecting elements In this letter, we investigate the effect of co-channel interference (CCI) on RIS-based dual-hop mixed free-space optical (FSO)-radio frequency (RF) communication systems The source node, equipped with multiple FSO apertures, transmits subcarrier intensity modulated symbols on the FSO link subjected to Gamma-Gamma (GG) distributed atmospheric turbulence with pointing errors (PEs) It is assumed that the relay-RIS and RIS-destination links follow Rayleigh distribution The destination node is corrupted by multiple CCI (each following Rayleigh distribution) The performance of the considered system is evaluated by deriving novel closed-form expressions for the outage probability (OP) and bit error rate (BER) It is shown through numerical results that RIS-based dual-hop mixed FSO-RF system provide a significant performance enhancement in comparison to a traditional dual-hop mixed FSO-RF system even in presence of CCI

Impact of Hardware Impairment and Co-Channel Interference on Security-Reliability Trade-Off for Wireless Sensor Networks

Abstract: In this paper, we investigate the security and reliability trade-off (SRT) for a wireless sensor network (WSN) which consists of one cluster head (CH), multiple users, and one eavesdropper (E), where the eavesdropper attempts to tap the confidential transmission between multiple users and CH. We first present two multiuser scheduling schemes, namely the selection combining (SC) scheme and the switch-and-examine combining with post-selection (SECps) scheme to enhance physical-layer security (PLS) of the WSN system. For comparison purposes, the round-robin scheduling (RRS) scheme is also considered as a baseline. Then, we analyze the SRT of the RRS, SECps, and SC schemes by deriving their closed-form outage and intercept probability expressions under the joint impact of hardware impairment (HI) and co-channel interference (CCI). And, secrecy diversity analysis of the three schemes is also carried out. Numerical results show that the SC and SECps scheme outperform the RRS scheme in terms of the SRT performance, where the SC scheme can achieve the best SRT performance at the cost of an increased channel estimation complexity. Moreover, a trade-off between the security and reliability can be achieved for each of the RRS, SECps, and SC schemes by adjusting the overall data rate and signal-to-noise ratio (SNR).

Inter-Beam Co-Channel Downlink and Uplink Interference for 5G New Radio in mm-Wave Bands

Abstract: This paper presents a methodology for assessing co-channel interference that arises in multi-beam transmitting and receiving antennas used in fifth-generation (5G) systems. This evaluation is essential for minimizing spectral resources, which allows for using the same frequency bands in angularly separated antenna beams of a 5G-based station (gNodeB). In the developed methodology, a multi-ellipsoidal propagation model (MPM) provides a mapping of the multipath propagation phenomenon and considers the directivity of antenna beams. To demonstrate the designation procedure of interference level we use simulation tests. For exemplary scenarios in downlink and uplink, we showed changes in a signal-to-interference ratio versus a separation angle between the serving (useful) and interfering beams and the distance between the gNodeB and user equipment. This evaluation is the basis for determining the minimum separation angle for which an acceptable interference level is ensured. The analysis was carried out for the lower millimeter-wave band, which is planned to use in 5G micro-cells base stations.

Efficient Resource Allocation for Multi-UAV Communication Against Adjacent and Co-Channel Interference

Abstract: Unmanned aerial vehicle (UAV) swarm has emerged as a promising novel paradigm to achieve better coverage and higher capacity for future wireless network by exploiting the more favorable line-of-sight (LoS) propagation. To reap the potential gains of UAV swarm, the remote control signal sent by ground control unit (GCU) is essential, whereas the control signal quality are susceptible in practice due to the effect of the adjacent channel interference (ACI) and the external interference (EI) from radiation sources distributed across the region. To tackle these challenges, this paper considers priority-aware resource coordination in a multi-UAV communication system, where multiple UAVs are controlled by a GCU to perform certain tasks with a pre-defined trajectory. Specifically, we maximize the minimum signal-to-interference-plus-noise ratio (SINR) among all the UAVs by jointly optimizing channel assignment and power allocation strategy under stringent resource availability constraints. According to the intensity of ACI, we consider the corresponding problem in two scenarios, i.e., Null-ACI and ACI systems. By virtue of the particular problem structure in Null-ACI case, we first recast the formulation into an equivalent yet more tractable form and obtain the global optimal solution via Hungarian algorithm. For general ACI systems, we develop an efficient iterative algorithm for its solution based on the alternating optimization methods. Extensive simulation results demonstrate that the proposed algorithms can significantly enhance the minimum SINR among all the UAVs and adapt the allocation of communication resources to diverse mission priority.

Modeling Co-Channel Interference in the THz Band

Abstract: Terahertz (THz) wireless technology is envisioned to enable terabit-per-second (Tbps) and secure transmissions in sixth-generation (6G) communication networks and has attracted attention from academia and industry in recent years. Because the transmission range of THz radios is restricted compared to that of microwave radios, frequency reuses in the THz band become much more flexible and even possible among transceiver pairs in close proximity. However, without appropriate spatial arrangement and coordination, the frequency reuse in the THz band can also lead to severe co-channel interference and result in a low signal-to-interference-plus-noise ratio (SINR) or a signal-to-interference ratio (SIR), which finally degrades signal detection and network reliability. To thoroughly study the co-channel interference in the THz band, we model the co-channel interference by the compound channel model and analyze it in detail. The adopted channel model captures the key features of THz communication, such as, spreading loss, molecular absorption loss, and dynamic shadowing, which is much different and complicated than those used in the low-frequency band. The resulted SINR and SIR are investigated by approximating the sum of co-channel interference as a gamma distribution. The generalized analytical results are also reduced to specialized forms for two special cases, i.e., the single-interferer case and the case of multiple independent and identically distributed (i.i.d.) interferers. Due to the generalized nature of the THz interference model constructed in this paper, the results play a meaningful role in practical implementation and can be easily extended to advanced performance analyses for THz communication systems.

Determination of LCR for Multi-branch SC Receiver under the Effects of α-κ-µ Fading and Weibull Co-Channel Interference

Abstract: To face confront the requirements of 5G wireless communication systems, there are still many challenges such as increasing capacity and data rate, the less delay, greater spectral and energy efficiency, ... Also, the goal is to increase transmission reliability by reducing the errors and the outage probability. For that purpose, the characteristics of a wireless system in the presence of α-κ-μ fading and Weibull co-channel interference (CCI) are studied in this work. The multi-branch selection combining (SC) receiver is implemented for reducing the effects of multipath fading and co-channel interference. The level crossing rate (LCR) of the signal to interference ratio (SIR) at the output of the receiver is derived and graphically presented. The fading parameters' influence is analyzed based on drawn graphics.

Co-Channel Interference Effects on Downlink Power-Domain Non-Orthogonal Multiple Access

Abstract: This paper investigates the fundamental performance limits of downlink power-domain non-orthogonal multiple access network in the presence of co-channel interference. The investigation considers that base-station makes multiple information exchanges with a designated mobile terminal via the power-domain non-orthogonal multiple access technique. The investigation also considers that the designated mobile terminal is under the effect of a limited number of co-channel interference, which are independent and identical distributed random variables subject to Rayleigh fading. Analytical, asymptotic, and Monte-Carlo based intensive computer simulation results reveal that co-channel interference causes coding gain losses on free-interference case, utilized as a benchmark, in high signal-to-noise-ratios. Outage probability, error probability, ergodic rate, and throughput performance metrics are considered for the performance analysis. Optimization techniques and also asymptotic analysis are provided.

Investigation on energy harvesting enabled device-to-device networks in presence of co-channel interference

Abstract: Energy harvesting from ambient radio-frequency (RF) sources has been a novel approach for extending the lifetime of wireless networks. In this paper, a cooperative device-to-device (D2D) system with the aid of energy-constrained relay is considered. The relays are assumed to be able to harvest energy from information signal and co-channel interference (CCI) signals broadcasted by nearby traditional cellular users and forward the source’s signal to its desired destination (D2D user) utilizing amplify-andforward (AF) relaying protocol. Time switching protocol (TSR) and power splitting protocol (PSR) are proposed to assist energy harvesting and information processing at the relay. The proposed approaches are applied in a model with three nodes including the source (D2D user), the relay and the destination (D2D user), the system throughput is investigated in terms of the ergodic capacity and the outage capacity, where the analytical results are obtained approximately. Our numerical results verify the our derivations, and also points out the impact of CCI on system performance. Finally, this investigation provide fundamental design guidelines for selecting hardware of energy harvesting circuits that satisfies the requirements of a practical cooperative D2D system.

System Imperfections on the Overall Performance of MC-CDMA-Based Cognitive Radio Network (CRN) System

Abstract: Cognitive radio network (CRN) is considered to be the future technology for the fifth generation of cellular wireless standards (5G) CRN is based on a complex spectrum allocation system, and licen

Derivation and Simulation of Outage Probability for 5G Wireless System with L-branch SC Receiver Influenced by Rician Fading and Nakagami-m Co-channel Interference

Abstract: The performance of wireless 5G communication system with L-branch selection combining (SC) receiver, will be analyzed in this article. The transmitted signal suffers from a small-scale Rician fading and Nakagami-m co-channel interference (CCI). The SC combiner with L branches is being implemented in the receiver to reduce the impacts of multipath fading to the system performance as outage probability (P out ), bit error probability (BEP), … The expression for the outage probability based on the signal to interference ratio (SIR) at the output of the SC receiver will be derived. The influence of parameters (Rician factor, Nakagami-m fading severity parameter, the mean values of the signal and interference powers, the number of the SC combiner input branches) on the P out will be examined. Then, the Graphics Processing Unit (GPU) accelerated simulation and linear optimization for designing the optimal 5G mobile networks will be used. This program provides significantly faster calculation of the system performance, such as P out , for the wireless channels and maximize the Quality of Service (QoS) for a 5G wireless systems under the influence of mentioned nuisances.

Outage probability simulation of a MIMO L-branch SC diversity system with k-µ fading and Rayleigh co-channel interference

Abstract: In this paper, a wireless MIMO communication system with L-branch selection combining (SC) receiver operating over short-term k-µ fading and Rayleigh interference channel, is studied. Signal at the receiver undergoes a small-scale k-µ fading, while co-channel interference (CCI) undergoes Rayleigh fading. Analytical expression for the outage probability (P out ) of the signal to interference ratio at the output of SC receiver is evaluated. The impact of the Rician factor, the mean value of the signal and interference power, the number of clusters and the number of branches of the SC combiner on the P out is analyzed and discussed. In a simulated environment for the described conditions, we have implemented GPGPU programming with the aim to increase the rate of calculations of fading and maximizing the Quality of Service (QoS) for a given system.

Modeling of co-channel interference in bluetooth low energy based on measurement data

Abstract: The intense use of the 2.4 GHz ISM band by several wireless technologies has resulted in increased co-channel interference between networks operating in this frequency band. The aim of this paper is to investigate modeling techniques of co-channel interference affecting bluetooth low energy devices. The models are derived from recorded interference. Two types of models are introduced: a time domain model utilizing IQ data as reference and a spectrum-based model in which the reference signal is captured in frequency domain by a real-time spectrum analyzer. The recorded interference is also used as a reference to analyze the accuracy of proposed models. The proposed IQ-based model shows a degradation in performance for the environments with dominant bluetooth interfering signals. The frequency-based model not only addresses this problem, but also results in a huge data decimation in recording the interference.

Multi-slot energy harvesting wireless communication in interference environment.

Abstract: Radio frequency energy harvesting (EH) technology can harvest the electromagnetic energy in the surrounding environment, and reduce the dependence of the communication devices on battery or power grid as power source, which is a very promising means of energy substitution and acquisition scheme. The random characteristics of wireless channel fading and possible co-channel interference (CCI) have great influence on EH efficiency and wireless communication performance with more complicated theoretical analysis. In this paper, the exact closed-form expressions of effective throughput of "harvest-store-use" and "harvest-use" multi-slot EH schemes with Rayleigh channel fading and CCI are derived theoretically. The simulation results show that in Rayleigh fading channels with CCI, CCI is beneficial to energy harvesting of EH device, but it will deteriorate the reception of required signals by information receiving device. Although there are obvious differences in working mechanism, working conditions and communication performance between the "harvest-store-use" scheme and the "harvest-use" scheme, the optimal time slot should be selected to balance the transmission probability and delay, minimize the interference of CCI to the desired signal, and improve the energy conversion efficiency of the energy harvester.

User equipment coordination for co-channel interference mitigation

Abstract: Techniques and apparatuses are described for enabling user equipment to coordinate for interference cancelation. In some aspects, base stations (121, 122) form a user equipment-coordination set (410) by pairing a first UE (111) of a first base station (121) with a second UE (112) of a second base station (122). The UE (111) receives a first downlink transmission (440) from the first base station (121). The UE 111 receives, from the second UE (112), information regarding a second downlink transmission (420) of the second base station (122). Based on the received information, the UE (111) can model and cancel interference from the second downlink transmission (430) of the second base station (122) to a reception of a first downlink transmission by the first base station (121) to the first UE (111).

Outage Performance of Macrodiversity Reception in the Presence Rayleigh Short-Term Fading and Co-channel Interference

Abstract: This paper presents a wireless macrodiversity communication system consisting of a receiver for macrodiversity selection combining (SC) receiver and two microdiversity SC receivers operating over correlated Gamma shadowed Rayleigh multipath fading environment in the presence of co-channel interference subject to Rayleigh short-term fading. First, we derive expression for cumulative distribution function of output signals of the both microdiversity SC receivers, and then capitalizing on it, we evaluate outage probability of the macrodiversity reception. The obtained probability outage results, both numerical and those obtained by simulation, as well as, the influence of Gamma long-term severity parameter and the correlation coefficient, are graphically illustrated and discussed.

Performance analysis of Mixed MUD-RF/Multi-aperture FSO Relay Communication System with Co-channel Interference

Abstract: This paper discusses the performance of an improved dual-hop mixed radio frequency (RF) / free space optical (FSO) relay communication system in the present of multiple co-channel interferences (CCIs) at the relay node. Multi-user diversity(MUD) technology has been adopted to improve the RF link performance. In order to improve the performance of the FSO link, multi-aperture receiver scheme has been implemented. The multi-user RF link experiences Nakagami-m fading, while the FSO link is subjected to Exponentiated Weibull distributed atmospheric turbulence. Moreover, the CCIs at the relay node are assumed to undergo Nakagami-m fading. For this proposed system, the exact closed-form expression for the outage probability (OP) has been derived. To quickly understand the effects of different parameters on the system performance, the asymptotic expression for the case of high signal-to-noise (SNR) has been further presented. Results show that the diversity order of this proposed system is min (αβM/2,m1K), where M represents the number of receiver apertures; K denotes the number of users; α, β and m1 are the channel parameters. Additionally, the effects of various parameters on system performance have been investigated. Finally, the numerical results have been validated by Monte-Carlo simulations.

Co-channel interference prediction method for satellite-to-ground downlink under low earth orbit satellite constellation

Abstract: Disclosed is a co-channel interference prediction method for a satellite-to-ground downlink under a low earth orbit satellite constellation. The method comprises: acquiring a co-channel interference value within a first pre-determined duration and a co-channel interference value within a second pre-determined duration; constructing, on the basis of a dropout wavelet neural network, a co-channel interference model according to the co-channel interference value within the first pre-determined duration; updating a parameter of the co-channel interference model; inputting the co-channel interference value within the second pre-determined duration into the updated co-channel interference model, and obtaining an accuracy level; determining whether the accuracy level is greater than an accuracy threshold; if so, re-constructing the co-channel interference model; if the accuracy level is less than or equal to the accuracy threshold, outputting the updated co-channel interference model; and predicting a co-channel interference value of each link at a next time point according to the updated co-channel interference model. The present invention realizes a prediction of a co-channel interference value on the basis of a dropout wavelet neural network, thereby lowering algorithm complexity while improving the prediction speed.

Method for suppressing cell co-channel interference, and base station and system

Abstract: Specifically disclosed is a method for suppressing cell co-channel interference, wherein same belongs to the technical field of communications. The method comprises: providing, on the basis of a physical cell identifier of a cell, a carrier frequency band for a terminal according to a resource allocation strategy, wherein a frequency band resource of the cell in the resource allocation strategy is divided into n frequency domain sections, n is an integer greater than or equal to two, and a resource allocation sequence is specified. Further provided are a base station, a communication system, an electronic device, and a computer-readable medium.

Accurate Signal Recovery in UHF Band Reuse-1 Cellular OFDMA Downlinks

Abstract: Accurate signal recovery is challenging for non-co-located transmit antennae deployments due to Inter Tower Interference (ITI) in reuse-1 cellular OFDMA networks. In the sub-1 GHz UHF band where only SISO deployment is possible, interference aware receiver algorithms are essential to mitigate the ITI. In this work, we develop a Joint Modified Least Squares (JmLS) algorithm for channel estimation in the presence of ITI. Firstly, it is shown that the JmLS algorithm achieves the Cramer-Rao lower bound. Next, an approach to managing the possibly distinct carrier frequency offsets of the different co-channel signals of interest is proposed. This improves the quality of the bit-level Joint Log-Likelihood Ratio. Finally, the impact of the choice of pilot sub-carrier information in the block modulated air-interface on the coded block error rate performance is studied. In particular, a comparison is made between (i) frequency orthogonal pilots from the different sectors, vis-a-vis, (ii) a pilot-on-pilot arrangement using pseudo-orthogonal sequences. The study indicates that based on the extent of frequency selectivity and the number of interferers being considered, (ii) is advantageous when the set of ITI pilots incident on a receiver is small when compared to the set of all possible pilots.

Method and device for reducing co-channel interference, and base station

Abstract: Embodiments of the present application provide a method and device for reducing co-channel interference, and a base station. The method comprises: a relay eNodeB (ReNB) receiving a propagation delay transmitted by a donor eNodeB (DeNB), wherein the propagation delay is a delay of propagation between the DeNB and the ReNB; and adjusting, according to the propagation delay, a timing parameter used by the ReNB to transmit uplink data and to receive downlink data, wherein the timing parameter is a delay of the ReNB relative to the DeNB. A DeNB is used as a reference for a propagation delay between the DeNB and a ReNB to delay timing used by the ReNB to receive downlink data, so as to ensure that the transmission of downlink data by the ReNB does not interfere with reception of downlink data by relay user equipment (RUE). Timing used by the ReNB to transmit uplink data is advanced, so as to ensure that the transmission of uplink data by the ReNB does not interfere with the reception of uplink data by the RUE.

Co-channel Interference Cancellation Method Based on Deep Neural Network for LEO Satellite Systems

Abstract: Low earth orbit (LEO) satellite navigation augmentation system has higher ground received signal power and faster Doppler change than Global Navigation Satellite System (GNSS), improving the positioning accuracy with occlusion and shortening the time of integer ambiguity-fixing. Aggressive frequency reuse reduces the complexity of user receiver implementation, but causing harsh co-channel interference at the meantime. The co-channel interference cancellation can alleviate the interference and improve orbit determination precision with receivers on board LEO satellites. Hence, this paper proposes a method based on deep neural network, which can accurately reconstruct the transmitted signal component coupled into the receiver, and then eliminate its interference to the weak GNSS signal. Finally, a simulation analysis is carried out with the BDS B1 frequency signal, which illustrates that this method can be adapted to different types of non-ideal channels. This method has good co-channel interference cancellation effect, and provides a technical reference for signal broadcasting of LEO navigation augmentation.

Cooperative Vehicle Platoon Intra-communications over Space-Time Correlated Rice fading Channels with co-channel Interference

Abstract: This paper investigates the performance of vehicle platoon intra-communications in the presence of node relaying cooperation. In the proposed scenario, all nodes are allowed to relay the signals of other entities towards the next/final destination. This improves channel conditions by mimicking large scale (virtual) antennas, thereby achieving the concept of cooperative diversity. The scenario considers a platoon of J vehicles assisted by a set of relay nodes. These potential relays include the same vehicles of the platoon, as well as base stations (BSs) and/or road-side units (RSUs). The objective is to evaluate the delay experienced by a packet transmitted by the leader towards all the vehicles of the formation. Each vehicle and each relayingable node is considered to relay the correctly received message to the remaining entities, but most importantly to all the vehicles of the platoon. We consider that if a given transmission attempt is not successfully received by all entities, then the transmitter and relays with a correct copy of the transmission engage in a persistent retransmission scheme that stops only when the packet has been correctly received by all the vehicles. Instantaneous and ideal feedback is used in all calculations. The criterion used to consider a packet correctly received by the destination is that the instantaneous signal-to-interference-plus-noise ratio (SINR) surpasses a reception threshold. It is assumed that the destination nodes store a copy of all the received transmissions over consecutive time slots and antenna elements. These signals are processed using ideal maximum-ratio combining (MRC) to obtain a more reliable copy of the information (i.e. using time and/or retransmission diversity). Multiple antennas are used by all the vehicles and nodes of the network under analysis. Novel spatial and temporal correlation tools are introduced in the channel model with Rice fading statistics and co-channel interference. Results suggest that RSUs can considerably reduce delay of platoons with large numbers of vehicles or large distances between elements. The degree of improvement also depends on channel correlation and the number of co-located antennas.

Triggering client roaming in a high co-channel interference environment

Abstract: In one embodiment, a device in a wireless network receives telemetry data from a plurality of autonomous vehicles. The telemetry data is indicative of radio signal quality metrics experienced by the vehicles at a particular location over time. The device forms an array of wireless roaming thresholds by applying regression to the telemetry data. The device computes an optimum roaming threshold from the array of wireless roaming thresholds to be used by the vehicles when approaching the location. The device triggers, based on the computed optimum threshold, one or more of the autonomous vehicles to initiate access point roaming when approaching the particular location.

Internet of Things (IoT) for MC-CDMA-Based Cognitive Radio Network (CRN) in 5G: Performance Results

Abstract: Both the internet-connected devices, i.e. IoT and Cognitive Radio Network (CRN) are considered to be the future technologies for the fifth generation of cellular wireless standards (5G). On the one...