Showing papers on "Co-channel interference published in 2018"
TL;DR: In this paper, the authors provided 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.
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 distributions, respectively. Moreover, we suggest channel state information (CSI)-assisted relaying or variable relaying gain based amplifiy-and-forward 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 Partial relay selection with outdated CSI is assumed as a relay selection protocol based on the knowledge of the RF CSI.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 statistics, such as the cumulative distribution function, the probability density function, the higher order moments, the amount of fading and the moment generating function, 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.
88 citations
TL;DR: In this article, the authors proposed a multiple-antenna aided adaptive coding and modulation (ACM) for aeronautical communications, which switches its coding and modality according to the distance between the communicating aircraft, which is readily available with the aid of the airborne radar or the global positioning system.
Abstract: In order to meet the demands of “Internet above the clouds,” we propose a multiple-antenna aided adaptive coding and modulation (ACM) for aeronautical communications. The proposed ACM scheme switches its coding and modulation mode according to the distance between the communicating aircraft, which is readily available with the aid of the airborne radar or the global positioning system. We derive an asymptotic closed-form expression of the signal-to-interference-plus-noise ratio (SINR) as the number of transmitting antennas tends to infinity, in the presence of realistic co-channel interference and channel estimation errors. The achievable transmission rates and the corresponding mode-switching distance-thresholds are readily obtained based on this closed-form SINR formula. Monte-Carlo simulation results are used to validate our theoretical analysis. For the specific example of 32 transmit antennas and four receive antennas communicating at a 5-GHz carrier frequency and using 6-MHz bandwidth, which are reused by multiple other pairs of communicating aircraft, the proposed distance-based ACM is capable of providing as high as 65.928-Mb/s data rate when the communication distance is less than 25 km.
63 citations
TL;DR: The secrecy performance of transmit antenna selection/maximal ratio combining systems in the absence and presence of co-channel interference (CCI) over closed-form expressions is considered and asymptotic secrecy outage analysis is provided.
Abstract: In this paper, the secrecy performance of transmit antenna selection/maximal ratio combining systems in the absence and presence of co-channel interference (CCI) over η-μ fading channels is considered. In particular, closed-form expressions for the secrecy performance are derived. To investigate the secrecy diversity gain, we also provide asymptotic secrecy outage analysis. Results show that the achievable secrecy diversity gain is 2μNT ND regardless of the number antennas of the eavesdropper NE, where NT and ND are the number antennas of the legitimate transmitter and receiver, respectively. Furthermore, it shows that the asymptotic secrecy performance is only dependent on the ratio γE /γD for both the systems with and without CCIs, regardless of the values of PI, where PI is the power of the interference. Finally, we provide some numerical examples to illustrate the presented analytical expressions.
34 citations
TL;DR: The results show that while multi-antenna terminals improve the system performance, the detrimental effect of CCI on FD relaying is clearly seen and it is unveiled that MIMOFD relaying could significantly improve theSystem performance compared to its conventional MIMo HD relaying counterpart.
Abstract: In this paper, a comprehensive design and analysis of multiple-input multiple-output (MIMO) full-duplex (FD) relaying systems in a multi-cell environment is investigated, where a multi-antenna amplify-and-forward FD relay station serves multiple half-duplex (HD) multi-antenna users. The pivotal obstacles of loopback self-interference (LI) and multiple co-channel interferers (CCI) at the relay and destination when employing FD relaying in cellular networks are addressed. In contrast to the HD relaying mode, the CCI in the FD relaying mode is predicted to double since the uplink and downlink communications are simultaneously scheduled via the same channel. In this paper, the optimal layout of transmit (receive) precoding (decoding) weight vectors which maximizes the overall signal-to-interference-plus-noise ratio is constructed by a suitable optimization problem, and then a closed-form sub-optimal formula based on null space projection is presented. The proposed hop-by-hop rank-1 zero-forcing (ZF) beamforming vectors are based on added ZF constraints used to suppress the LI and CCI channels at the relay and destination, i.e., the source and relay perform transmit ZF beamforming, while the relay and destination employ receive ZF combining. To this end, unified accurate expressions for the outage probability and ergodic capacity are derived in closed form. In addition, simpler tight lower bound formulas for the outage probability and ergodic capacity are presented. Moreover, the asymptotic approximations for outage probability are considered to gain insights into system behavior in terms of the diversity order and array gain. Numerical and simulation results show the accuracy of the presented exact analytical expressions and the tightness of the lower bound expressions. The case of hop-by-hop maximum-ratio transmission/maximal-ratio combining beamforming is included for comparison purposes. Furthermore, our results show that while multi-antenna terminals improve the system performance, the detrimental effect of CCI on FD relaying is clearly seen. Therefore, our findings unveil that MIMO FD relaying could significantly improve the system performance compared to its conventional MIMO HD relaying counterpart.
26 citations
TL;DR: In this paper, the performance of adaptive time reversal (ATR)-MIMO is investigated by a parametric study approach, and the results reveal which characteristic of an acousticwavefield affects the performance and how the performance saturates when the multipath environment changes.
Abstract: The relationship between the performance of time-reversal-based multiple-input/multiple-output (MIMO) communication technique and the changes in the multipath environment is investigated quantitatively. In this study, the performance of adaptive time reversal (ATR)-MIMO is investigated by a parametric study approach. The ATR-MIMO communication technique is applied to the multipath-rich synthetic shallow sea acoustic dataset. We focused on discussing about the relationship among the changes in the multipath environment, the number of transmissions, the capability of ATR-MIMO to remove cochannel interference (CCI), and the efficiency of utilization of the energy of the multipath. The results reveal which characteristic of an acousticwavefield affects the performance of ATR-MIMO and how the performance saturates when the multipath environment changes. It is also demonstrated that ATR-MIMO can utilize the energy of the multipath as effectively as the passive-time-reversal-based single-input/multiple-output communication technique in a Gaussian-noise-dominant environment.
21 citations
TL;DR: This paper studies the secrecy performance of the proposed system when maximal ratio combining is employed and derives a novel analytical expression for the exact intercept probability, which takes into account the number of interfering signals and the fading characteristics of the wireless environment.
Abstract: In this paper, the joint effect of fading and co-channel interference on the secrecy performance of a wireless communications system is studied. Considering a practical setting where a transmitter (Alice) communicates with a multi-antenna legitimate receiver (Bob) in the presence of a multi-antenna eavesdropper (Eve), we study the secrecy performance of the proposed system when maximal ratio combining is employed. The probability density function and cumulative distribution function of the output signal-plus-interference-to-noise ratio are derived. Given these formulations, we derive a novel analytical expression for the exact intercept probability, which takes into account the number of interfering signals and the fading characteristics of the wireless environment. In addition, we provide a comprehensive diversity analysis, where we derive simple asymptotic intercept probability expressions and explicitly show the impact of system parameters on the diversity order and secrecy coding gain. Throughout the asymptotic analysis, we consider various scenarios based on the interfernece-to-noise ratios at the legitimate receiver and the eavesdropper, as well as the average signal-to-noise ratio of the eavesdropper and examine their impact on the physical layer security of the wireless system. Finally, Monte-Carlo simulations are conducted to assess our proposed analysis.
17 citations
TL;DR: This work analytically model VANETs based on the well-known cluster model, and discloses that an error floor is introduced at high signal-to-noise-ratio (SNR) due to imperfect channel estimation.
Abstract: Vehicular Ad hoc Networks (VANETs) are considered to be a novel solution for provisioning of infotainment services and reduction of accidents on the road. However, communication in VANETs is significantly hampered by multipath fading and co-channel interference. In this context, we analytically model VANETs based on the well-known cluster model. The closed form expression for packet error probability is derived in the presence of co-channel interference under α - μ fading. Impact of α and μ on interference is also characterized in detail. We also incorporate the impact of channel estimation errors of main and interfering link to provide more realistic evaluation of packet error probability. We then provide performance evaluation of VANETs under cooperative communication and quantify the improvements in the performance of cluster. We also evaluate the importance of fading parameters α and μ in the presence of interfering signal from nearby cluster. Our findings disclose that an error floor is introduced at high signal-to-noise-ratio (SNR) due to imperfect channel estimation. Additionally, the error probability considerably reduces by applying cooperative scheduling. Extensive simulations are performed in MATLAB to validate our results, which also prove the practicality of our analytical model.
16 citations
TL;DR: Close-form expressions of the secrecy outage probability are derived for the proposed PCSI-US and FCSI-US schemes as well as conventional round-robin scheduling schemes in co-channel interference (CCI) environments to validate the secrecy effectiveness of the proposed user scheduling methods in terms of combating the CCI.
Abstract: This paper analyzes the secrecy outage probability of a cellular downlink system which consists of multiple users, one base station (BS), and one eavesdropper in the presence of co-channel interferers, where the BS transmits its signals to users which are distributed according to a Poisson point process with a fixed density, while the eavesdropper attempts to tap the transmission from the BS to the users. To enhance the transmission security against eavesdropping, we propose two multiuser scheduling schemes, namely, the partial channel state information (CSI) aided user scheduling (PCSI-US) scheme where only the CSIs of users are available without knowing the co-channel interferers’ CSIs and the full CSI aided user scheduling (FCSI-US) scheme which requires the CSIs of both users and interferers. For comparison purposes, the conventional round-robin scheduling scheme is also considered as a baseline. We derive closed-form expressions of the secrecy outage probability for the proposed PCSI-US and FCSI-US as well as conventional round-robin scheduling schemes in co-channel interference (CCI) environments. Numerical results show that the proposed FCSI-US and PCSI-US schemes outperform the conventional round-robin scheduling in terms of their secrecy outage probabilities, where FCSI-US achieves the best secrecy outage performance in CCI environments. It is also demonstrated that increasing the mean number of users has a marginal effect on the secrecy performance of conventional round-robin scheduling, which can significantly decrease the secrecy outage probabilities of PCSI-US and FCSI-US schemes. This further validates the secrecy effectiveness of the proposed user scheduling methods in terms of combating the CCI.
15 citations
TL;DR: The use of quadrature space shift keying (QSSK) modulation for wireless sensor networks (WSNs) is proposed and verified the superiority of QSSK scheme as compared to traditional modulation techniques especially for high spectral efficiency.
Abstract: This paper proposes the use of quadrature space shift keying (QSSK) modulation for wireless sensor networks (WSNs). QSSK is a multiple input multiple output communication protocol that attracted substantial interest due to several promised inherent advantages. It has been shown in literature that QSSK scheme achieves high spectral efficiency with low average error probability, high energy efficiency, and very simple transmitter and receiver architectures. Hence, its use in WSNs is very promising to ameliorate the major limitations of such networks. The performance of a WSN with QSSK modulation and in the presence of co-channel interference is studied in this paper. A closed form expression for the average pair wise error probability is derived and used to obtain a tight upper bound on the overall average bit error ratio. Obtained results verified the superiority of QSSK scheme as compared to traditional modulation techniques especially for high spectral efficiency.
14 citations
02 Apr 2018
TL;DR: This paper considers that co-channel interference signals are present at the user destination node of a downlink land mobile satellite (LMS) system and derives an accurate expression for secrecy outage probability (SOP) of the considered LMS system.
Abstract: In this paper, we investigate the secrecy performance of a downlink land mobile satellite (LMS) system, where a satellite transmits signal to a legitimate user in the presence of an eavesdropper at the ground. Herein, we consider that co-channel interference signals are present at the user destination node. By leveraging the statistics of underlying Shadowed-Rician fading channels for satellite links and Nakagami-m fading for interfering terrestrial links, we derive an accurate expression for secrecy outage probability (SOP) of the considered LMS system. To gain more insights, we derive an asymptotic expression for SOP at high signal-to-noise ratio regime and illustrate that system can attain a unity diversity order even under the influence of interferers. Subsequently, we also deduce the expression for probability of non-zero secrecy capacity. The analytical results are validated through Monte-Carlo simulations and utilized to reveal the impact of various key channel/system parameters in understanding the physical layer security aspects of LMS system.
11 citations
TL;DR: The upper bound and the lower bound of the achievable rate for the interference-unaware receive transformation (IURT), which does not require interference knowledge or precoding, are derived to obtain the criterion for making IURT become interference free in multiple-input–multiple-output (MIMO) systems under co-channel interference.
Abstract: In this letter, we derive the upper bound and the lower bound of the achievable rate for the interference-unaware receive transformation (IURT), which does not require interference knowledge or precoding, to obtain the criterion for making IURT become interference free in multiple-input–multiple-output (MIMO) systems under co-channel interference. We prove that if the receive-antenna number is larger than or equal to the interference-free threshold, which is equal to the summation of the transmit-antenna number and the interference’s covariance-matrix rank, then the derived upper bound reaches the interference-free MIMO channel capacity. Furthermore, we prove that by increasing both the transmit-antenna number and the receive-antenna number the derived lower bound can come closer to the interference-free MIMO channel capacity. Simulation results show that if the receive-antenna number is larger than the interference-free threshold, then the achievable rate of IURT can achieve the interference-free MIMO channel capacity.
TL;DR: In this paper, the authors derived the data-aided error vector magnitude (EVM) in an interference limited system when both the desired channel and interferers experience independent and non-identically distributed ''kappa - \mu $ shadowed fading''.
Abstract: In this paper, we derive the data-aided error vector magnitude (EVM) in an interference limited system when both the desired channel and interferers experience independent and nonidentically distributed $\kappa - \mu $ shadowed fading. Then, it is analytically shown that the EVM is equal to the square root of number of interferers when the desired channel and interferers do not experience fading. Furthermore, the EVM is derived in the presence of interference and noise, when the desired channel experiences $\kappa - \mu $ shadowed fading and the interferers experience independent and identical Nakagami fading. Moreover, using the properties of the special functions, the derived EVM expressions are also simplified for various special cases.
14 Jun 2018
TL;DR: This paper applies multi-user MMSE-SVD with ICI information to OFDM downlink and SC uplink to discuss the impact of number of multiplexed UEs.
Abstract: Recently, we proposed a multi-user spatial multiplexing technique called the minimum mean square error filtering combined with singular value decomposition (MMSE-SVD) for a distributed multiple input multiple output (MIMO) network. Multi-user MMSE-SVD applies the MMSE filter at macro base station (MBS) to suppress inter-user interference (IUI) and interantenna interference (IAI), while the eigenmode filter constructed by SVD at user equipments (UEs) to suppress IAI. To improve the link capacity in multicell environment, the inter-cell interference (ICI) from adjacent macro-cells is taken into account in generating the MMSE filter. In this paper, we apply multi-user MMSE-SVD with ICI information to OFDM downlink and SC uplink to discuss the impact of number of multiplexed UEs.
TL;DR: In this paper, a multi-user orthogonal-based cognitive radio network with cochannel interference (CCI) mitigation is studied and the correct reception probability (CRP) model is introduced as a network utility metric.
Abstract: In this paper, we study the utility fairness resource allocation in a multi-user orthogonal-based cognitive radio network with cochannel interference (CCI) mitigation. In our proposed system model, we introduce the correct reception probability (CRP) model as a network utility metric. Furthermore, useful bounds on CRP are derived to analyze the performance of proposed allocation schemes. The optimal resource allocation is formulated as a worst-case user CRP maximum problem with both average CCI and average power budget constraints. However, this problem is non-convex and generally challenging to solve. Therefore, we solve this problem by successively performing subchannel allocation and power allocation. Firstly, a $k$ -means clustering inspired subchannel allocation strategy is proposed to divide secondary users (SUs) into multiple groups by minimizing the average mutual-signal-to-interference-ratio degree between any two SUs. The concept of reference user is employed to guarantee the quality of service of the primary user. In each subchannel, we formulate a max-min utility optimal power allocation problem. The non-linear Perron Frobenius theory is applied to solve this power allocation problem. Simulation results show that the proposed resource allocation scheme is fair and has relatively fast convergence.
Patent•
26 Oct 2018
TL;DR: In this article, the authors proposed a method for evading co-channel interference through deflection antenna pointing and a satellite communication system, which consists of the following steps: arranging more than one space-borne antenna on an NGEO communication satellite, determining a constellation configuration of the NGEO satellite communications system, and selecting variables to describe the normal orientation of the spaceborne antenna.
Abstract: The invention relates to a method for evading co-channel interference through deflection antenna pointing and a satellite communication system The method comprises the following steps: arranging morethan one space-borne antenna on an NGEO communication satellite; determining a constellation configuration of the NGEO satellite communication system, and ground user type and distribution, and selecting variables to describe the normal orientation of the space-borne antenna of the NGEO satellite communication system; according to an interference protection regulation for the GEO satellite systemof ITU, selecting a group of indexes alpha for balancing the interference degree of the satellite communication system to the GEO satellite system; determining a group of indexes beta for balancing link quality of the satellite communication system; establishing a nonlinear optimization model of the normal orientation of the phased array antenna according to the indexes alpha and the indexes beta; and solving optimal variables through iterations and outputting a set of optimal phased array antenna deflection pointing setting scheme The method for evading co-channel interference through deflection antenna pointing and the satellite communication system in the present invention ensure own communication link quality and reliability requirements, so that the satellite system can coexist effectively with the GEO satellite system at the same frequency
TL;DR: Compressive sensing (CS) and correlation-based method are shown to provide accurate estimates of the Power Angular Profile (PAP) and the interference cancellation capabilities of CS beamforming are combined with a Space–Time Division Multiple Access (STDMA) scheduling scheme.
TL;DR: The authors investigate space frequency block code with frequency-switched transmit diversity (FSTD) in indoor visible light communications (VLCs) in order to mitigate the co-channel interference (CCI) through a cooperative transmission and thereby improve system reliability.
Abstract: The authors investigate space frequency block code (SFBC) with frequency-switched transmit diversity (FSTD) in indoor visible light communications (VLCs) in order to mitigate the co-channel interference (CCI) through a cooperative transmission and thereby improve system reliability. In addition, the authors explore the influence of parameters, the semi-angle at half power and the position of the light emitting diodes (LEDs), on the bit error rate (BER) performance. Although VLC is a promising technology for indoor wireless communications, it is necessary to cope with the CCI that occurs when the coverage areas of multiple LEDs overlap and the LEDs are sending different signals. The desired signal experiences serious interference from other LEDs to the point that it is impossible to recover the signal without coding. They investigate SFBC-FSTD in a multiple-input single-output-VLC system composed of four LEDs and one photodiode. It is effective in this scenario because the data rate is not affected by the code rate. Through computer simulations, SFBC-FSTD exhibits great improvement in the BER performance, requiring a lower signal-to-noise ratio than SFBC and single-input single-output. Furthermore, SFBC-FSTD is more power efficient.
TL;DR: Joint transmit and receive beamforming design for a full-duplex multiple-input multiple-output amplify-and-forward relay system with simultaneous wireless information and power transfer in WSNs is investigated and an iterative algorithm based on alternating optimization with successive convex approximation which converges to a local optimum is proposed to solve the non-convex problem.
Abstract: The simultaneous wireless information and power transfer (SWIPT) technique has been regarded as an appealing approach to prolong the lifetime of wireless sensor networks. However, co-channel interferences with SWIPT in wireless networks have not been investigated from a green communication perspective. In this paper, joint transmit and receive beamforming design for a full-duplex multiple-input multiple-output amplify-and-forward relay system with simultaneous wireless information and power transfer in WSNs is investigated. Multiple co-channel interferers are considered at the relay and destination sensor nodes. To minimize the mean-squared-error of the system, joint source and relay beamforming optimization is proposed while guaranteeing the transmit power constraints and destination's energy harvesting constraint. An iterative algorithm based on alternating optimization with successive convex approximation which converges to a local optimum is proposed to solve the non-convex problem. Moreover, a low-complexity scheme is derived to reduce the computational complexity. Simulations for MSE versus iterations and MSE versus signal-to-noise ratio (SNR) demonstrate the convergence and good performance of the proposed schemes.
20 May 2018
TL;DR: A co-channel interference suppression method is proposed in this paper that approximates the covariance matrix of the interference by approximating the difference between the covariant matrices of the received signal and the desired signal to improve the robustness of the method.
Abstract: Ultra dense heterogeneous networks (UDHN) is one of the leading ideas in fifth generation (5G) mobile communication systems to improve the spectrum efficiency and the energy efficiency. In future 5G systems, users will be able to use the diverse radio access technologies (RATs) simultaneously. However, one of crucial issues in spectral sharing 5G UDHN is the co-channel interference among the small cell base stations (SCBSs) in different networks, such as cellular and WiFi networks. In order to mitigate the co-channel interference in the receiver, a co-channel interference suppression method is proposed in this paper. In this method, the covariance matrix of the interference is first approximated by the difference between the covariance matrices of the received signal and the desired signal. Subsequently, diagonal loading is adopted to generate the estimated covariance matrix of the interference to improve the robustness of the method. Simulation results are presented to demonstrate the advantage of the proposed algorithm.
01 Dec 2018
TL;DR: The obtained results demonstrate the impact of the residual SI and CCI on the E2E performance of the DNF-FD-OWRC and demonstrate the ability of DNF -OWRC to improve the throughput of a conventional half-duplex (HD) OWRC.
Abstract: In this paper, we study the impact of the co-channel interference (CCI) in conjunction with the impact of residual self-interference (SI) on the end-to-end (E2E) performance of a denoise-and-forward full-duplex one-way relay channel (DNF-FD-OWRC) network. The investigated system comprises one source node S, which communicates with one destination node $D$ with the aid of an FD relay node, over Rayleigh fading channels. Closed-form expressions for the cumulative distribution function (CDF) and the distribution of the E2E signal-to-interference and noise ratio (SINR) are derived and presented. Moreover, a closed-form expression for the E2E outage probability is presented and validated using Monte Carlo simulations. The obtained results demonstrate the impact of the residual SI and CCI on the E2E performance of the DNF-FD-OWRC and demonstrate the ability of DNF-OWRC to improve the throughput of a conventional half-duplex (HD) OWRC.
TL;DR: This paper investigates secure transmission resource allocation problem for multi-antenna wireless powered communication networks (WPCNs) where a full-duplex wireless device sends confidential signals to an information receiver (IR), and an energy transmitter is employed to provide radio energy to the FD WD and to jam the multiple eavesdroppers at the same time.
01 Nov 2018
TL;DR: The proposed method finds interfered samples within an ADS-B signal and excludes them from measuring the signal strength, and removes only the effect of signal collision while preserving theeffect of multipath.
Abstract: Automatic Dependent Surveillance - Broadcast (ADS-B) signals, which are periodically broadcasted by aircraft, can be measured as a new means of air-ground radio propagation measurement. However, one drawback of this approach is that co-channel interference degrades the measurement accuracy. To overcome this issue, this paper proposes a method for accurate ADS-B signal strength measurement. The proposed method finds interfered samples within an ADS-B signal and excludes them from measuring the signal strength. By considering the characteristics of signal collision and multipath, the proposed method removes only the effect of signal collision while preserving the effect of multipath.
01 Aug 2018
TL;DR: This paper re-derive two types of uplink interference considering the geometrical relationship and dependency between typical base station (BS) and other cell nodes (e.g., BS and or) user equipment (UE) and derives outage probabilities on the D-TDD and IFD systems under the homogeneous network focusing on the uplink direction.
Abstract: New duplexing methods are emerging to improve spectral efficiency (SE) and reduce delay as wireless network evolves. Dynamic time division duplexing (D-TDD) and in-band full duplex (IFD) systems are strong candidate technologies for next-generation wireless communication. Recently, many studies about above two duplexing methods have been conducted through stochastic geometry models. For uplink direction, however, existing studies do not adequately reflect the geographical characteristics of the newly introduced interference. In this paper, to increase the accuracy of analysis, we re-derive two types of uplink interference considering the geometrical relationship and dependency between typical base station (BS) and other cell nodes (e.g., BS and(or) user equipment (UE)). Also, we analyze the outage probabilities on the D-TDD and IFD systems under the homogeneous network focusing on the uplink direction. The results show that our derived outage probability matches very well with the Poisson Point Process (PPP) simulation among the existing uplink analysis.
TL;DR: A joint load balanced stable routing and communication segment assignment algorithm is proposed that considers jointly the mobility prediction, mitigating the co‐channel interference and energy consumption, and introduced weighting function to keep routes away from the PU's region.
TL;DR: An enhanced inter-lighting interference cancellation (E-ILIC) is proposed in order to distinguish the received signals, combating the equal powers at the receiver side and hence improve the average bit error rate (BER) performance of a multiple-input-single-output visible light communication (VLC) system.
Abstract: In this study, the authors propose an enhanced inter-lighting interference cancellation (E-ILIC) in order to distinguish the received signals, combating the equal powers at the receiver side and hence improve the average bit error rate (BER) performance of a multiple-input-single-output visible light communication (VLC) system. VLC is a promising technology for indoor environments, it makes use of the light emitting diode (LED) lamps already installed to transmit information through the visible light. When several LEDs transmit simultaneously different data to increase the transmission capacity, it leads to co-channel interference that degrades the BER performance. For this reason, they investigate E-ILIC that is a combination of ILIC with closed loop power control to receive the signals with different power level. It employs power allocation at the transmitter when the received power ratio does not comply with a specific threshold. Furthermore, it reduces significantly the interference between adjacent LED lamps, obtaining useful information at the receiver side. Through computer simulations, E-ILIC achieves the best average BER performance in any user position when the assignment of the power weights is correctly performed on the LEDs.
TL;DR: In this paper, the authors present and discuss the results of practical experiments performed to determine the impact of adjacent and co-channel interference on the throughput of the IEEE 802.11ac Wave 1 radio links.
Abstract: The goal of this paper is to present and discuss the results of practical experiments performed to determine the impact of adjacent and co-channel interference on the throughput of the IEEE 802.11ac Wave 1 radio links. Measurements were done in two scenarios: the first only in presence of a foreign link and the second with transmission in a foreign link and with different combinations of radio channel width in observed and foreign 802.11ac Wave 1 links. The obtained results can be used to design new Wi-Fi networks as well as to expand the existing ones. Streszczenie. Artykuł omawia wyniki praktycznych eksperymentów mających na celu określenie wpływu zakłóceń sąsiedniokanałowych i wspólnokanałowych na przepustowość sieci IEEE 802.11ac Wave 1. Pomiary zostały wykonane zarówno w warunkach jedynie obecności obcej sieci, jak i przy transmisji odbywającej się w tej sieci. W przeprowadzonych badaniach uwzględniono różne kombinacje szerokości kanału radiowego w obu sieciach. (Eksperymentalna analiza podatności sieci IEEE 802.11ac Wave 1 na zakłócenia wspólnokanałowe i sąsiedniokanałowe).
TL;DR: Analyzing the performance of a cellular network based on uni‐directional IFD (UD‐IFD) communication, wherein an IFD base station simultaneously supports downlink and uplink transmissions of half‐duplex (HD) users, shows that capacity gain was not obtained and the capacity improved when applying the proposed MP‐CCIC.
06 Feb 2018
TL;DR: This chapter proposes a framework to enable an optical back-haul cooperation among different optical network units (ONUs) with distributed MIMO techniques in wireless front-haul for next-generation optical-wireless cellular networks.
Abstract: In future fifth-generation (5G) wireless cellular networks, distributed massive multipleinput multiple-output (MIMO) techniques will be appliedworldwide. Recently, muchmore challenges on efficient resource allocation to large numbers of user equipment (UE) are raised in order to support their high mobility among different micro-/pico-cells. In this chapter, we propose a framework to enable an optical back-haul cooperation among different optical network units (ONUs) with distributed MIMO techniques in wireless front-haul for next-generation optical-wireless cellular networks. Specifically, our proposal is featured by a downlink resource multi-cell sharing scheme for OFDMA-based passive optical network (PON) supporting radio-over-fiber (RoF). We first consider system architecture with the investigation of related works, and then we propose a co-channel interference mitigation and delay-aware sharing scheme for real-time services allowing each subcarrier to be multi-cell shared by different active ONUs corresponding to different micro-/pico-cells. Furthermore, a heuristic algorithm to mitigate co-channel interference, maximize sharing capacity, and minimize network latency is given by employing the graph theory to solve such sharing problems for future 5G. Finally, simulations are performed to evaluate our proposal.
Posted Content•
TL;DR: In this paper, the authors considered an orthogonal frequency division multiplexing OFDM-based CR network and investigated the tradeoff between increasing the SU transmission rate and reducing the interference levels at the PUs.
Abstract: In cognitive radio (CR) networks, secondary users (SUs) are allowed to opportunistically access the primary users (PUs) spectrum to improve the spectrum utilization; however, this increases the interference levels at the PUs. In this paper, we consider an orthogonal frequency division multiplexing OFDM-based CR network and investigate the tradeoff between increasing the SU transmission rate (hence improving the spectrum utilization) and reducing the interference levels at the PUs. We formulate a new multiobjective optimization (MOOP) problem that jointly maximizes the SU transmission rate and minimizes its transmit power, while imposing interference thresholds to the PUs. Further, we propose an algorithm to strike a balance between the SU transmission rate and the interference levels to the PUs. The proposed algorithm considers the practical scenario of knowing partial channel state information (CSI) of the links between the SU transmitter and the PUs receivers. Simulation results illustrate the performance of the proposed algorithm and its superiority when compared to the work in the literature.
TL;DR: The outage probability, channel capacity and symbol error rate (SER) performance of device-to-device (D2D) communication systems is investigated and the performance of D2D communication system is discussed under various conditions of interference, path-loss and channel fading.
Abstract: In this paper, we investigate the outage probability, channel capacity and symbol error rate (SER) performance of device-to-device (D2D) communication systems. The D2D communication system is affected by several co-channel interferers. Gamma fading channel is considered for the D2D communication system. The channel for the co-channel interference is assumed to be Nakagami faded. An expression for the probability density function (PDF) of the signal-to-interference ratio (SIR) is presented. The PDF is a function of distances between various devices in the D2D system, path-loss, channel fading conditions and signal powers. Based on the PDF expression, we present the expressions for the outage, channel capacity and SER. With the help of numerical results the performance of D2D communication system is discussed under various conditions of interference, path-loss and channel fading.