Interference Mitigation Scheme Research Articles

Mixed Uplink, Downlink Channel Allocation and Power Allocation Schemes for 5G Networks

Device-to-device (D2D) communication plays a significant role for the next generation networks i.e. (5G). The D2D communication leads to an efficient spectral utilization which results in a potential reduction in the overhead at the evolved node B side. However, without an efficient interference management scheme in place, cellular users experience a degradation in the quality of service, which makes interference mitigation a major deployment challenge. In this paper, we have put forward an efficient interference mitigation scheme in order to maximize the system throughput. This scheme comprises of three subparts. Firstly, we introduce a cell sub-division concept under which we virtually subdivide the cell into three regions, namely center, mid and outer regions. Secondly, we formulate the power allocation problem as a robust particle swarm optimization algorithm for the mid-cell region. This enables the scheme in handling the uncertainties in the allocated power, thus reaching a robust optimal solution. The third part consists of a resource allocation scheme built around a cell subdivision concept. Extensive simulations are performed under the scenarios of simultaneous uplink and downlink transmission for the center cell region and the outer cell region. We further draw the comparison of our scheme along with the schemes mentioned in the literature.

Decentralized Learning Based Indoor Interference Mitigation for 5G-and-Beyond Systems

Due to the explosive growth of data traffic, and poor indoor coverage, ultra-dense network (UDN) has been introduced as a fundamental architectural technology for 5G-and-beyond systems. As the telecom operator is shifting to a plug-and-play paradigm in mobile networks, network planning, and optimization become difficult, and costly, especially in residential small-cell base stations (SBSs) deployment. Under this circumstance, severe inter-cell interference (ICI) becomes inevitable. Therefore, interference mitigation is of vital importance for indoor coverage in mobile communication systems. In this paper, we propose a fully distributed self-learning interference mitigation (SLIM) scheme for autonomous networks under a model-free multi-agent reinforcement learning (MARL) framework. In SLIM, individual SBSs autonomously perceive surrounding interferences, and determine downlink transmit power without necessity of signaling interactions between SBSs for mitigating interferences. To tackle the dimensional disaster of joint action in the MARL model, we employ the Mean Field Theory to approximate the action value function to greatly decrease the computational complexity. Simulation results based on 3GPP dual-stripe urban model demonstrate that SLIM outperforms several existing known interference coordination schemes in mitigating interference, and reducing power consumption while guaranteeing UEs’ quality of service for autonomous UDNs.

Analysis of SIR and Rate Meta Distributions for 3D Heterogenous Ultra-Dense Networks With Joint Offloading and Resource Partitioning

In heterogeneous ultra-dense networks (HUDNs), load balancing is always considered by offloading users from the macro base station (MBS) tier to the small base station (SBS) tier, to alleviate the data traffic of the MBS tier, while it causes a serious problem that the offloaded users will suffer strong interference from the MBS tier, and hence the signal-to-interference ratio (SIR) is in low region for the offloaded users. In order to improve the performance of these offloaded users, an interference mitigation scheme based on resource partitioning is employed in the literature. Specifically, a fraction of resource blocks (RBs) is reserved for the offloaded users, and then the SIRs of these users will be enhanced because there is only interference from the SBS tier. In summary, the combination of offloading and resource partitioning is called joint offloading and resource partitioning scheme, which has been investigated in the HUDNs built on the 2D space, while it has rarely been deliberated in 3D HUDNs that are used to model the scenario of high-rise buildings. Moreover, a two-tier 3D HUDN is proposed in this paper, and the MBS and SBS tiers are modeled as two independent Poisson point processes. Then, the SIR and rate meta distributions, which are used to characterize the fraction of users that achieve a desired link reliability given SIR or rate thresholds, are formulated for the proposed 3D HUDN. Lastly, numerical results show that with the usage of the joint offloading and resource partitioning scheme, the performance of the proposed 3D HUND can be significantly improved.

Interference Mitigation Using Angular Diversity Receiver With Efficient Channel Estimation in MIMO VLC

Visible Light Communication (VLC) is a promising solution to meet the ever increasing demand for indoor data connectivity with high bit rates. VLC uses the license-free bands and provides high-speed connections unlike RF wireless communication. However; indoor VLC suffers from performance degradation due to either co-channel interference (CCI) or inter-symbol interference (ISI). In this paper, an interference management scheme is proposed for VLC Multi-Input Multi-Output (MIMO) based systems. The scheme reduces the number of interfered signals by using a constrained field-of-view angular diversity receiver CFOV-ADR and then uses least-square (LS) channel estimation with maximum-likelihood (ML) equalizer to resolve the interfered signals. The proposed interference mitigation scheme using constrained-FOV-ADR with channel estimation IM-CFOV-CE enables frequency reuse of one. The bit-error-rate (BER) is calculated at various room positions with different receiver’s heights and rotation angles. The performance evaluation results reveal that the proposed system can achieve a higher number of downlink channels and superior BER performance than that of without CCI management. Also, the proposed scheme has been compared with Time Division Multiple Access (TDMA) technique, and achieves enhanced performance at all positions and orientations of the ADR.

Transmission Energy Minimization for Heterogeneous Low-Latency NOMA Downlink

This paper investigates the transmission energy minimization problem for the two-user downlink with strictly heterogeneous latency constraints. To cope with the latency constraints and to explicitly specify the trade-off between blocklength (latency) and reliability the normal approximation of the capacity of finite blocklength codes (FBCs) is adopted, in contrast to the classical Shannon capacity formula. We first consider the non-orthogonal multiple access (NOMA) based transmission scheme. However, due to heterogeneous latency constraints and channel conditions at receivers, the conventional successive interference cancellation may be infeasible. We thus study the problem by considering heterogeneous receiver conditions under different interference mitigation schemes and solve the corresponding NOMA design problems. It is shown that, though the energy function is not convex and does not have closed form expression, the studied NOMA problems can be globally solved semi-analytically and with low complexity. Moreover, we propose a hybrid transmission scheme that combines the time division multiple access (TDMA) and NOMA. Specifically, the hybrid scheme can judiciously perform bit and time allocation and take TDMA and NOMA as two special instances. To handle the more challenging hybrid design problem, we propose a concave approximation of the FBC rate/capacity formula, by which we obtain computationally efficient and high-quality solutions. Simulation results show that the hybrid scheme can achieve considerable transmission energy saving compared with both pure NOMA and TDMA schemes.

Interference Mitigation via Sparse Coding in ${K}$ -User Interference Channels

In this letter, we propose a signal recovery scheme for interference mitigation in ${K}$ -user interference channels. The recurrent structure of communication signals is investigated, based on which a single-user region (SUR) detection scheme involving sparse coding (SC) is proposed. A dictionary is constructed directly over SURs detected. Recovery of signal in the principal link is then implemented via a template matching step over the dictionary. Comparing with existing signal recovery schemes involving SC, main contributions include: 1) the proposed scheme is significantly more practical as it no more relies on clean signals as a prior for dictionary construction and 2) traditional time-consuming dictionary training is avoided, thus the computation complexity is remarkably lowered. Simulation results show that SURs in the received signal can be accurately recognized via the proposed SUR detection scheme. Moreover, the signal recovered by the proposed scheme is of higher quality, under lower time consumption and without clean signal as a prior , comparing with existing scheme.

Performance of Next-Generation Cellular Networks Guarded With Frequency Reuse Distance

In this paper, we lay an analytic framework for computing the downlink success probability of cellular networks, taking into account a frequency reuse distance as an interference mitigation scheme. We model the frequency reuse distance using tools from stochastic geometry, namely, we utilize the Matern hard-core (MHC) point process to capture the effect of interference protection zones created around base stations. To model the overall cellular network, we introduce a new point process composed of $N$ superimposed MHC processes, where each individual MHC process corresponds to a co-channel base station group; this new point process is called the union-MHC (UMHC) process. We further investigate the resulting performance of the UMHC process and present the link success probability in integral form. The success probability can be evaluated for an arbitrary fading model and an arbitrary number of orthogonal resource groups. We test the newly proposed model against the practical data sets from a network operator and observe a good match of the results.

Interference Mitigation and Power Allocation Scheme for Downlink MIMO–NOMA HetNet

In this paper, a novel interference mitigation and power allocation (PA) scheme is investigated for downlink non-orthogonal multiple access (NOMA) with multiple input multiple output (MIMO) technology in heterogeneous networks (HetNets). The proposed scheme, named PA based interference alignment and coordinated beamforming (PA-IA-CB), consists of two stages. The first stage applies two steps of IA-CB; one step for canceling the inter-cluster and the co-tier interference among small cells, whereas the other step deals with the inter-cluster interference within the macro cell. In the second stage, the cross-tier interference is proposed to be managed by properly handling the allocated power to the macro base station (MBS) and the small base stations (SBSs). The PA problem is modeled as a non-cooperative game between the MBS and the SBS with the aim of increasing the system sum rate. Simulation results verify the efficiency of the proposed technique in terms of total system sum rate and outage probability compared to the conventional schemes.

Interference reduction in long‐term evolution‐advanced by frequency and power domains

Mobile communication systems are growing steadily. In addition, users require better quality of service and large coverage offering a high quality of signal. To meet these challenges, a new concept named heterogeneous network (Het‐Net) has been adopted. The Het‐Net is a network deploying different types of cells (from a macro shape up to femto ones). Operators look to improve the performance of their networks and to remedy the problem of areas with low coverage. However, the coexistence of these different cell models causes interference at the downlink which can affect offered signal's quality. This interference results therefore performance degradation. Therefore, a novel intercell interference mitigation scheme, based on frequency and power domain, is proposed in order to reduce interference in Het‐Net long‐term evolution‐advanced. In frequency domain, the macrocell has to allocate a frequency band by using fractional frequency reuse scheme and the femtocells choose subbands that are not used in the macrocell sector to reduce interference. On the other hand, the small cells transmitted powers are controlled for limiting the interference imposed by it on the other users in the cell area. Simulation results show that the proposed scheme enhances the signal to interference plus noise ratio of macro and femto users and the overall throughput in the network.

Energy Efficiency of Multiple Antenna Cellular Networks Considering a Realistic Power Consumption Model

We analyze the area energy efficiency (AEE) of a cellular network employing spatial multiplexing (SM), maximal ratio transmission and transmit antenna selection (TAS) schemes. Moreover, we consider a realistic power consumption model for small base stations (BSs), which includes the power consumed by the backhaul as well as different interference attenuation levels. Our goal is to maximize the AEE by deploying the optimal number of BSs given some requirements, such as demanded network capacity, amount of interference and employed MIMO scheme. Results show that TAS performs better in terms of AEE when the interference is not fully canceled and for no interference cancellation when the demand for system capacity is lower, while SM becomes more energy efficient when the demanded capacity is higher. Additionally, when the capacity demand and the area to be covered are fixed, we show that although achieving the highest AEE, TAS also demands more small BSs than SM. The system performance in terms of AEE is shown to be strongly dependent on the amount of interference, which in turn depends on the employed interference-mitigation scheme and on the power consumption model.

Coverage analysis of ultra-dense heterogeneous cellular networks with interference management

Deploying ultra-dense small base stations (SBSs) in the coverage umbrella of a macro base station (MBS) requires proactive users offloading form MBS to SBSs to achieve maximum performance gain in heterogeneous cellular networks. However, it degrades the signal-to-interference-plus-noise ratio (SINR) of the offloaded users due to strong interference received from MBS. To improve users’ SINR, an efficient interference mitigation scheme is required to be used in conjunction with users offloading. Soft frequency reuse (SFR) is an attractive and spectrally efficient interference mitigation scheme that allocates available bandwidth among all cell users associated with $$k{\text{BS}}$$, where $$k\in ({\text{M}},{\text{S}})$$. To address the problem of interference, we use the SFR scheme together with power control factor $$(\beta )$$ to transmit at different power levels for interior and edge regions of $$k{\text{BS}}$$, i.e., $$r^i_{k} \,{\text{and}}\, r^e_{k}$$, respectively. We further consider uniform and nonuniform SBS distribution in the premises of MBS and analyse the effect of the SFR scheme on the proposed model with the help of Stochastic geometry. Mathematical expressions for coverage probabilities are derived and validated through simulations. Numerical results show that the proposed model achieves better coverage probability due to reduced interference. Moreover, nonuniform SBS distribution together with the SFR scheme further improves the performance gain of the proposed model.

Interference Analysis of PLC Convergence System

In this paper, we propose a convergence system with visible light communication (VLC) and powerline communication (PLC) for home network. Also, we analyze the performance of interference mitigation scheme for the proposed system model. The proposed system is able to offer multimedia services with high speed in indoor wireless environment. Interference scenario is suggested to demonstrate the proposed system. And the scenario analyzed by applying minimum mean square error (MMSE) and zero-forcing (ZF) schemes to reduce the interference. From simulation results, we confirm that interference has a significant effect on the proposed system performance and the applied detectors are highly effective for interference mitigation.

Stable Wireless Network Control Under Service Constraints

We consider the design of wireless queueing network control policies with particular focus on combining stability with additional application-dependent requirements. Thereby, we consequently pursue a cost function based approach that provides the flexibility to incorporate constraints and requirements of particular services or applications. As typical examples of such requirements, we consider the reduction of buffer underflows in case of streaming traffic, and energy efficiency in networks of battery powered nodes. Compared with the classical throughput optimal control problem, such requirements significantly complicate the control problem. We provide easily verifiable theoretical conditions for stability, and, additionally, compare various candidate cost functions applied to wireless networks with streaming media traffic. Moreover, we demonstrate how the framework can be applied to the problem of energy efficient routing, and we demonstrate the application of our framework in cross-layer control problems for wireless multihop networks, using an advanced power control scheme for interference mitigation, based on successive convex approximation. In all scenarios, the performance of our control framework is evaluated using extensive numerical simulations.

Fractional Frequency Reuse Scheme for Device to Device Communication Underlaying Cellular on Wireless Multimedia Sensor Networks.

Wireless multimedia sensor networks (WMSNs) have been improved with the increase of multimedia data. In WMSNs, a centralization problem can occur because of large-size multimedia data. It is necessary to consider device-to-device (D2D) communication. We focus on D2D WMSN based on cellular networks. Sensors in the D2D WMSN can non-orthogonally use a cellular link, which is a wireless communication channel between a sensor and an aggregator, and a D2D link, which is the channel between sensors. As a result, it has more complex interference environments than an ordinary system. Therefore, it is a key factor to manage the varying inter-cell interference effectively for throughput improvement. We propose an interference mitigation scheme that can be applied to D2D WMSN. In the proposed scheme, a cell is separated into six zones and orthogonal frequency is allocated to each zone for cellular links. The frequencies allocated to cellular links are reused by D2D links of neighboring zones. The simulation results show that the throughput of the proposed scheme increases two times compared to a static frequency allocation scheme.

Neural network-based path loss model for cellular mobile networks at 800 and 1800 MHz bands

Cellular radio communication systems have become essential for data/voice/video/multimedia applications. The performance of cellular communication radio systems is assessed by considering the design specifications of frequency planning, channel assignment and interference mitigation strategies among others. Frequency planning is the most important component to improve capacity or quality of cellular radio systems. Large-scale path loss values between the base station and mobile stations are the key regulating factors that limit the performance of cellular systems, especially in urban/vegetation region. There is a necessity to develop a suitable path loss prediction model for predicting path loss values based on received signal strength measurements. In this paper, an ANN-based path loss model was used for macro cell measurement data obtained in the Vijayawada urban region, India. The Multi-Layer Perceptron (MLP) neural network model was considered. The prediction results indicate that the ANN model outperformed the Auto Regressive Moving Average (ARMA) and COST-231-WImodels. The outcome of this research work will be immensely useful for improving coverage and ensuring better frequency planning of cellular radio systems.

Investigation on Interference Mitigation Schemes for Next Generation Cellular Communications

The fanciful quick development and exponential increment of advanced mobile phones the remote info activity request is additional within the returning years. That forces reexamining current remote cell arranges thanks to the shortage of the accessible vary. 2 noteworthy difficulties for advancing future Evolution (LTE) systems area unit to accomplish improved cell scope and framework limit contrasted and broadband Code Division Multiple Access (WCDMA) framework. Powerful use of radio assets and thick vary use is at the middle to realize these objectives. Be that because it might, thick repeat use might increment between cell electric resistance, that so extraordinarily restricts the limit of shoppers within the framework. Between cell obstruction will limit general framework execution as so much as output and preternatural productivity, significantly for the shoppers set at the cell edge region. later on, cautious administration of between cell obstructions finishes up vital to boost LTE framework execution. during this paper, obstruction alleviation plans for LTE downlink systems area unit investigated. The eNB and also the Mobile-Femto as each provide similar assets and transfer speed. This has created AN electric resistance issue from the downlink signs of every alternative to their UEs. this examination has adjusted a adept repeat use conspire that worked powerfully finished separation and accomplished increased outcomes within the flag quality and output of Macro and Mobile-Femto UE once contrasted with past electric resistance administration plans e.g. Partial Frequency use factor1 (NoFFR-3) and uncomplete Frequency use factor3 (FFR-3). Keywords: The fanciful quick development and exponential increment of advanced mobile phones the remote info activity request is additional within the returning years. That forces reexamining current remote cell arranges thanks to the shortage of the accessible vary. 2 noteworthy difficulties for advancing future Evolution (LTE) systems area unit to accomplish improved cell scope and framework limit contrasted and broadband Code Division Multiple Access (WCDMA) framework. Powerful use of radio assets and thick vary use is at the middle to realize these objectives. Be that because it might, thick repeat use might increment between cell electric resistance, that so extraordinarily restricts the limit of shoppers within the framework. Between cell obstruction will limit general framework execution as so much as output and preternatural productivity, significantly for the shoppers set at the cell edge region. later on, cautious administration of between cell obstructions finishes up vital to boost LTE framework execution. during this paper, obstruction alleviation plans for LTE downlink systems area unit investigated. The eNB and also the Mobile-Femto as each provide similar assets and transfer speed. This has created AN electric resistance issue from the downlink signs of every alternative to their UEs. this examination has adjusted a adept repeat use conspire that worked powerfully finished separation and accomplished increased outcomes within the flag quality and output of Macro and Mobile-Femto UE once contrasted with past electric resistance administration plans e.g. Partial Frequency use factor1 (NoFFR-3) and uncomplete Frequency use factor3 (FFR-3).

Statistical Analysis and Optimization of a Fifth-Percentile User Rate Constrained Design for FFR/SFR-Aided OFDMA-Based Cellular Networks

Interference mitigation strategies are deemed to play a key role in the context of the next generation (B4G/5G) of multicellular networks based on orthogonal frequency division multiple access. Fractional and soft frequency reuse (FFR, SFR) constitute two powerful mechanisms for intercell interference coordination that have been already adopted by emerging cellular deployments as an efficient way to improve the throughput performance perceived by cell-edge users. This paper presents a novel optimal fifth-percentile user rate constrained design for FFR/SFR-based networks that, by appropriately dimensioning the center and edge regions of the cell, rightly splitting the available bandwidth among these two areas while assigning the corresponding transmit power, allows a tradeoff between cell throughput performance and fairness to be established. To this end, both the cumulative distribution function of the user throughput and the average spectral efficiency of the system are derived assuming the use of the ubiquitous proportional fair scheduling policy. The mathematical framework is then used to obtain numerical results showing that the novel proposed design clearly outperforms previous schemes in terms of throughput fairness control due to a more rational compromise between average cell throughput and cell-edge ICIC.

An Efficient Inter-Cell Interference Mitigation Scheme for Proximity Service in Cellular Networks

An Efficient Inter-Cell Interference Mitigation Scheme for Proximity Service in Cellular Networks

Joint virtual edge-clustering and spectrum allocation scheme for uplink interference mitigation in C-RAN

Fractional Frequency Reuse (FFR) and Coordinated MultiPoint (CoMP) processing are two of the conventional methods to mitigate the Inter-Cell Interference (ICI) and to improve the average Signal-to-Interference-plus-Noise Ratio (SINR). However, FFR is associated with low system spectral efficiency and CoMP does not take any action to mitigate the inter-cluster interference. In this article, we study the challenges and problems of the current interference management techniques and explain why the clustering and spectrum allocation must be studied jointly. Then, in the context of Cloud Radio Access Network (C-RAN), we propose a joint virtual clustering and spectrum allocation scheme, called Cloud-CFFR, to address such problems. With respect to both FFR and CoMP, Cloud-CFFR decreases the complexity, delay, and ICI while increasing the system spectral efficiency. Since the system performance in cell-edge regions relies on the cooperation of different Virtual Base Stations (VBSs), there is no service interruption in handling handovers; moreover, in order to address the unanticipated change in capacity demand, a flexible spectrum management technique is proposed which dynamically changes the subband boundaries based on the number of active users in the clusters. Simulation results confirm the validity of our analysis and show the benefits of this novel uplink solution compared to the traditional schemes.

Interference Alignment Assisted by D2D Communication for the Downlink of MIMO Heterogeneous Networks

To cope with the conflict between the increasing data traffic demands and scarcity of available spectrum resources in wireless networks, multi-tier heterogeneous networks within the same spectrum have been considered to be deployed to provide higher network capacity. However, the spectrum-coexist leads to serious interference. This paper investigates a novel interference alignment (IA) scheme assisted by device-to-device (D2D) communication (DaIA) under a multiple-input multiple-output Gaussian interference broadcast channel heterogeneous scenario. We focus on a hotspot area of communication within the macro cell coverage in which there are two small cells. There is already existing IA algorithm for the case that macro cell base station (BS) has two users. In this paper, we consider different setting that macro cell BS can serve more users. First, as an important aspect of IA, the feasibility conditions for the considered scenario are presented. It acts as a guideline to design the IA scheme. Then the DaIA scheme is proposed to efficiently manage the co-tier interference and inter-tier interference with the reduced channel state information (CSI). Specifically, the proposed DaIA scheme jointly designs precoders and receive filters in closed-form in which the paired users can directly interact with the CSI of interfering channels to design their receiving filters by exploiting D2D communication. Thus the total amount of effective CSI feedback acquired at the BS is greatly reduced. Moreover, we analyze the achievable degrees of freedom of the proposed DaIA scheme. Finally, for the small cells, the precoders and receive filters are further optimized to maximize their achievable rate by combining the water-filling algorithm and the singular value decomposition of the equivalent channel matrix. The simulation results indicate that the proposed DaIA scheme outperforms the conventional interference mitigation schemes.