Throughput Of Cellular Networks Research Articles

Reconfigurable intelligent surface passive beamforming enhancement using unsupervised learning

<p><span lang="EN-US">Reconfigurable intelligent surfaces (RIS) is a wireless technology that has the potential to improve cellular communication systems significantly. This paper considers enhancing the RIS beamforming in a RIS-aided multiuser multi-input multi-output (MIMO) system to enhance user throughput in cellular networks. The study offers an unsupervised/deep neural network (U/DNN) that simultaneously optimizes the intelligent surface beamforming with less complexity to overcome the non-convex sum-rate problem difficulty. The numerical outcomes comparing the suggested approach to the near-optimal iterative semi-definite programming strategy indicate that the proposed method retains most performance (more than 95% of optimal throughput value when the number of antennas is 4 and RIS’s elements are 30) while drastically reducing system computing complexity.</span></p>

D2D Assisted Cellular Networks in Licensed and Unlicensed Spectrum: Matching-Iteration-Based Joint User Access and Resource Allocation

Device-to-Device (D2D) communications, which enable direct communication between nearby user devices over the licensed spectrum, have been considered a key technique to improve spectral efficiency and system throughput in cellular networks (CNs). However, the limited spectrum resources cannot be sufficient to support more cellular users (CUs) and D2D users to meet the growth of the traffic data in future wireless networks. Therefore, Long-Term Evolution-Unlicensed (LTE-U) and D2D-Unlicensed (D2D-U) technologies have been proposed to further enhance system capacity by extending the CUs and D2D users on the unlicensed spectrum for communications. In this paper, we consider an LTE network where the CUs and D2D users are allowed to share the unlicensed spectrum with Wi-Fi users. To maximize the sum rate of all users while guaranteeing each user’s quality of service (QoS), we jointly consider user access and resource allocation. To tackle the formulated problem, we propose a matching-iteration-based joint user access and resource allocation algorithm. Simulation results show that the proposed algorithm can significantly improve system throughput compared to the other benchmark algorithms.

Joint channel allocation and power control based on PSO for cellular networks with D2D communications

Introducing D2D communications into wireless cellular networks is viewed as a potential method to relieve the increasing traffic in the base stations. However, the cellular users will suffer from high interference without efficient interference management scheme. In this paper, we study two joint channel allocation and power control problems with different constraints, and propose a joint channel allocation and power control scheme based on Particle Swarm Optimization (PSO) to efficiently manage interference and improve the network throughput. The proposed scheme deals with continuous powers and discrete channels simultaneously. By carefully designing the fitness values for the two problems, the algorithm avoids trapping into infeasible solutions. Numerous simulations show that the proposed algorithm could improve the network throughput in cellular networks with D2D communications, and the algorithm outperforms the compared non-joint interference management algorithm in terms of D2D throughput, cellular throughput, and further the overall network throughput.

Linear Multi-hop Amplify-and-Forward (AF) Cooperative Relay Channels

Cooperative relaying of channels between base station and user equipment emerged as a great technique to enhance the reliability and throughput of cellular networks. The relay nodes normally exploit amplify-and-forward (AF) scheme to relay the connection. Although there have been many previous works on cooperative issues, none of them have considered the fundamental trade-off between the communication reliability and transmission rate. Instead of considering the performance evaluated separately on the achievable rate or the error probability, the RCEE provide insight into fundamental trade-off between the transmission rate and the communication reliability in cooperative relay channels. It has been shown that multi-hop relay nodes are necessary to compensate the decreasing SNR over the distance. As a trade-off, the communication reliability in terms of RCEE is decreasing over the increase of multi-hop relay nodes with low SNR for a given data rate. Therefore, the optimization for the number of hops is preferable in the cooperative relay channels.Cooperative relaying of channels between base station and user equipment emerged as a great technique to enhance the reliability and throughput of cellular networks. The relay nodes normally exploit amplify-and-forward (AF) scheme to relay the connection. Although there have been many previous works on cooperative issues, none of them have considered the fundamental trade-off between the communication reliability and transmission rate. Instead of considering the performance evaluated separately on the achievable rate or the error probability, the RCEE provide insight into fundamental trade-off between the transmission rate and the communication reliability in cooperative relay channels. It has been shown that multi-hop relay nodes are necessary to compensate the decreasing SNR over the distance. As a trade-off, the communication reliability in terms of RCEE is decreasing over the increase of multi-hop relay nodes with low SNR for a given data rate. Therefore, the optimization for the number of hops is preferable in the cooperative relay channels.

A New Multicast Scheduling Scheme for Cellular Networks

In this paper, adaptive user selection for opportunistic multicast scheduling (A-OMS) is proposed to improve cellular network throughput. Unlike previous solutions, the number of users selected in each transmission time interval (TTI) is not considered to be a constant. A statistical approximation of the system throughput matrix is employed to choose the number of users in each TTI. This matrix is constructed once before transmission begins, so the computational complexity is low. An optimization problem is formulated to obtain the optimal user time allocations. Both an exhaustive search and a suboptimal heuristic search are considered. Results are presented which show that the proposed approach provides better performance than existing schemes.

A two-stage game theoretic approach for self-organizing networks

Growth of network access technologies in the mobile environment has raised several new issues due to the interference between the available access. Thanks to the currently used access methods such as the orthogonal frequency division multiple access in mobile networks and the long term evolution-advanced systems, the intra-cell interferences are avoided and the quality of service has increased. Nevertheless, the diversity and multiplicity of base stations in the network have left behind a major problem of inter-cell interferences. In this paper, we focus on the optimization of the total throughput of cellular networks using fractional frequency reuse and allowing each mobile user to individually choose its serving base station. We derive analytically the utilities related to the network manager and mobile users and develop a Stackelberg game to obtain the equilibrium. We propose a distributed algorithm that allows the base stations, using a light collaboration, to achieve an efficient utilization of the frequencies, with the optic of maximizing the total system utility. This algorithm is based on stochastic gradient descent which requires some information to be exchanged between neighboring base stations. At user association level, we propose an iterative distributed algorithm based on automata learning algorithm. Both algorithms allow the system to converge to the Stackelberg equilibrium. Furthermore, simulation results carried out based on a realistic network setting show promising results in terms of global utility and convergence issues. In this setting, we include scenarios with a varying number of users and address the problem of robustness and scalability of the proposed approach.

A New Adaptive Small-Cell Architecture

Small cells are an emerging approach to improving hotspots throughput in cellular networks. Unfortunately, they cannot be deployed in a large scale under current cellular architectures, because of a severe interference problem and inefficient use of spectrum. We propose a new small-cell architecture which reconfigures topologies and frequency bands, adapting to changing traffic demands and interference-mitigating requirements. The new architecture consists of distributed small-cell nodes (SCN) and co-located baseband units (BBU), and adaptively switches the connections between the SCNs and BBUs. The BBUs can even be shared among multiple SCNs that use different frequency bands. Our architecture requires fewer BBUs, and the spectrum and energy utilization is significantly more efficient compared with current architectures. Simulations show that the new architecture is able to increase the spectrum utilization by 23.5%, and improve the network satisfaction regarding traffic demands by 144.2% for small cells covering 0.5 km2. Our architecture can also reduce the investment and energy consumption of the BBUs by up to 40%.

Optimal modulation and coding scheme selection in cellular networks with hybrid-ARQ error control

We propose an optimal modulation and coding scheme (MCS) selection criterion for maximizing user throughput in cellular networks. The proposed criterion adopts both the Chase combining and incremental redundancy based hybrid automatic repeat request (HARQ) mechanisms and it selects an MCS level that maximizes the expected throughput which is estimated by considering both the number of transmissions and successful decoding probability in HARQ operation. We also prove that the conventional MCS selection rule is not optimized with mathematical analysis. Through link-level and system-level simulations, we show that the proposed MCS selection criterion yields higher average cell throughput than the conventional MCS selection schemes for slowly varying channels.

MuPAC: A new multi-power architecture for capacity enhancement in cellular networks

We have considered the problem of providing greater throughput in cellular networks. We propose a novel packet data cellular architecture, the Multi-Power Architecture for Cellular networks (MuPAC), based on multi-hop relaying with multiple channels. MuPAC has the unique capability of providing a coarse grained frequency reuse factor that contributes to its enhanced throughput. MuPAC utilizes multi-hop wireless relaying in the presence of the infrastructure nodes such as base station (BS) in order to provide a very high network capacity. Multiple data channels each of which is designated to operate at a different transmission power are used in order to provide a coarse grained frequency reuse factor. MuPAC also includes solutions to problems faced in multi-hop networks: performance degradation at high mobility, partitions, etc. MuPAC provides increased throughput compared to existing schemes such as the current day cellular systems which can be classified as single-hop cellular network (SCN), and the recently proposed multi-hop cellular network (MCN). We provide an analytical treatment of MuPAC to support its superiority over SCN and MCN. We also show using extensive simulations, that MuPAC performs well over a range of node densities, under high mobility, varying traffic generation characteristics and also improves fairness across a cell.

RT-MuPAC: A new multi-power architecture for voice cellular networks

We have considered the problem of providing greater throughput in cellular networks. We propose a novel cellular architecture, RT-MuPAC, that supports greater throughput compared to conventional cellular architectures. RT-MuPAC (Real-time Multi-power Architecture for Cellular Networks) is based on two fundamental features not present in today’s cellular networks: usage of multiple hops and power control (power control is used only in a limited way to reduce interference and save battery energy for the mobile nodes in today’s cellular networks). These features, we believe, will become increasingly important in next generation cellular systems as heterogeneous networks will operate in synergy. We also provide an analytical treatment of RT-MuPAC to support its superior performance. We show using detailed simulations that RT-MuPAC is indeed a significant improvement over conventional networks. We also discuss possible enhancements to the basic architecture in order to counter specific issues. RT-MuPAC can evolve from the existing infrastructure and offer advantages to both the service provider and the users. RT-MuPAC also serves as a proof of concept for the use of multi-hop architectures in cellular networks.

Optimizing the radio resource utilization of multiaccess systems with a traffic-transmission quality adaptive packet scheduling

In this paper we state a general framework for radio resource allocation based on a matrix which highlights the trade-offs of complexity and efficiency. This framework is outlined for the systematic definition of scheduling algorithms that are jointly adaptive to traffic and to transmission quality in order to improve the radio resource utilization and the achievable throughput of cellular networks for the support of best-effort traffic. We consider the application of the matrix concept to both time division and code division multiple access, the latter scheme also bringing about mutual interference among competing users. Then we propose a scheduling algorithm for wireless systems, called channel adaptive open scheduling (CHAOS). The CHAOS performance in terms of throughput and delay is extensively compared with those resulting from a load adaptive channel independent scheduling (CIS). A major result of this work is the quantitative assessment of the performance advantage allowed by jointly accounting for traffic congestion and transmission quality. Moreover the main implementation issues related to the proposed algorithms are investigated.