Services In Cellular Networks Research Articles

Delay Analysis in Full-Duplex Heterogeneous Cellular Networks

Heterogeneous networks (HetNets) as a combination of macro cells and small cells are used to increase the cellular network's capacity, and present a perfect solution for high-speed communications. Increasing area spectrum efficiency and capacity of HetNets largely depends on the high speed of backhaul links. One effective way that is currently utilized in HetNets is the use of full-duplex (FD) technology that potentially doubles the spectral efficiency without the need for additional spectrum. On the other hand, one of the most critical network design requirements is delay, which is a key representation of the quality of service in modern cellular networks. In this paper, by utilizing tools from the stochastic geometry, we analyze the local delay for downlink channel, which is typically defined as the mean number of required time slots for a successful communication. Given imperfect self-interference cancellation in practical FD communications, we utilize duplex mode (half-duplex (HD) or FD) for each user based on the distance from its serving base station. Further, we aim to investigate the energy efficiency for both duplexing modes, i.e., HD and FD, by considering local delay. We conduct extensive simulations to validate system performance in terms of local delay versus different system key parameters.

The role of caching in next generation cellular networks: A survey and research outlook

AbstractMobile applications and social networks tend to enhance the needs for high‐quality content access. To address the expeditious growing demand for data services in 5G cellular networks, it is important to develop distribution techniques and an efficient content caching, aiming to significantly reduce redundant data transmission and, thus, improve the efficiency of the networks. In modern communication systems, caching has emerged as a vital tool for reducing peak data rates. It is anticipated that energy harvesting and self‐powered small base stations are the fundamental part of next‐generation cellular networks. However, uncertainties in energy are the main reason to adopt energy efficient power control schemes to reduce SBS energy consumption and ensure the quality of services for users. Using the edge cooperative caching such as energy efficient design can also be achievable, which reduces the usage of the capacity limited SBSs backhaul and the energy consumption. To support the huge power demand of cellular network, renewable energy harvesting technologies can be leveraged. In addition to this, power supply to the infrastructures is the main challenge to the mobile network operators (MNOs) especially in terms of economic optimum, sustainability, and green energy in developing countries for the growth of cellular networks. Renewable energy–based solutions for MNOs not only reduce the overall carbon dioxide emissions but also provide numerous profits.

Spectrum allocation by wave based adaptive differential evolution algorithm

Resource allocation is very important in mobile communication. This paper studies the assignment of spectrum in cellular networks operated on orthogonal frequency division multiple access (OFDMA) system. Both network utility and fairness among all linked users are taken to measure quality of service in cellular networks. The problem is expressed as a maximization optimization model. Wave based adaptive differential evolution (WADE) algorithm is proposed to for spectrum allocation. The WADE algorithm adapts algorithmic parameters in wave propagation manner to accelerate convergence process of the algorithm. Simulation results show that WADE is more efficient than other compared algorithms. Moreover, it is effective to allocate spectrum resources in OFDMA-based cellular networks.

Implementation of RF Band-Pass Filter on UMTS Systems to Improve Quality of Service

A large number of cellular operators in an area causes high interference effects. One indicator is the problem with received total wideband power (RTWP) found in a universal mobile telecommunication system (UMTS). High RTWP is one of the causes of a decrease in the quality of service (QoS) in cellular communication networks. To solve this problem, an RF band-pass filter device can be implemented on a UMTS system, where RF band-pass filters have been designed and tested in previous studies. In this research, the RF band-pass filter was installed between the BTS node and bottom jumper. After implementing it, QoS measurements with the Huawei M2000 application and Drive Test were carried out. The QoS analysis included RTWP, Circuit-Switched access rate, Packet-Switched access rate, and Received Signal Code Power (RSCP) value. The results show that the RTWP value decreases, while the CS access rate, PS access rate, and RSCP value increase. These results indicate that QoS on the UMTS increases.

Iterative greedy user clustering algorithm for D2D–relay in vehicular communication systems

Device-to-device (D2D) communications help in improving the performance of wireless services in cellular networks via enabling cooperation among mobile users. Further, compared to traditional pairwise cooperation, cluster-wise cooperation can achieve even higher spectral and power efficiency. D2D clustering certainly can be a great supporting technology for the future of intelligent transportation. In this study, the authors investigate the D2D–relay clustering network in the vehicular scenario and propose a new clustering scheme named iterative greedy user clustering (IGUC). By exploiting those vehicles with better channel state, system resources can be saved. Here, they mainly focus on the question which is by applying D2D–relay clustering among vehicles, how much bandwidth could be saved in the uplink. This problem is mathematically formulated into a non-linear binary programming problem with the goal being minimum spectrum usage. Due to the NP-hardness, the low-complexity suboptimal algorithm IGUC is introduced to tackle it. Simulation results show that compared to the non-cooperative uplink system, IGUC saves a considerable proportion of the spectrum. Furthermore, clusters in denser and further areas tend to produce a higher gain. Influence of the fast time-varying characteristic of vehicular wireless channels is also investigated, upon which an adaptive switch mechanism is proposed to further facilitate IGUC.

Interference-Aware Channel Assignment Algorithm in D2D overlaying Cellular Networks

Device-to-Device (D2D) communications can provide proximity based services in the future 5G cellular networks. It allows short range communication in a limited area with the advantages of power saving, high data rate and traffic offloading. However, D2D communications may reuse the licensed channels with cellular communications and potentially result in critical interferences to nearby devices. To control the interference and improve network throughput in overlaid D2D cellular networks, a novel channel assignment approach is proposed in this paper. First, we characterize the performance of devices by using Poisson point process model. Then, we convert the throughput maximization problem into an optimal spectrum allocation problem with signal to interference plus noise ratio constraints and solve it, i.e., assigning appropriate fractions of channels to cellular communications and D2D communications. In order to mitigate the interferences between D2D devices, a cluster-based multi-channel assignment algorithm is proposed. The algorithm first cluster D2D communications into clusters to reduce the problem scale. After that, a multi-channel assignment algorithm is proposed to mitigate critical interferences among nearby devices for each D2D cluster individually. The simulation analysis conforms that the proposed algorithm can greatly increase system throughput.

A Device Performance and Data Analytics Concept for Smartphones’ IoT Services and Machine-Type Communication in Cellular Networks

With the advancement of new technologies, the number of connected devices, the amount of data generated, and the need to build an intelligently connected network of things to improve and enrich the human ecosystem open new doors to modifications and adaptations of current cellular network infrastructures. While more focus is given to low power wide area (LPWA) applications and devices, a significant challenge is the definition of Internet of Things (IoT) use cases and the value generation of applications on already existing IoT devices. Smartphones and related devices are currently manufactured with a wide range of smart sensors such as accelerometers, video sensors, compasses, gyros, proximity sensors, fingerprint sensors, temperature sensors, and biometric sensors used for various purposes. Many of these sensors can be automatically expanded to monitor a user’s daily activities (e.g., fitness workouts), locations, movements, and real-time body temperatures. Mobile network operators (MNOs) play a substantial role in providing IoT communications platforms, as they manage traffic flow in the network. In this paper, we discuss the global concept of IoT and machine-type communication (MTC), and we conduct device performance analytics based on data traffic collected from a cellular network. The experiment equips service providers with a model and framework to monitor device performance in a network.

An efficient bandwidth allocation scheme for hierarchical cellular networks with energy harvesting: an actor-critic approach

ABSTRACTIn this paper, we propose an efficient bandwidth allocation strategy for multiclass services in hierarchical cellular networks that consist of an operation controller, several small-cell base stations (SBSs), and a number of mobile users. Each SBS is equipped with a finite-capacity battery that is regularly recharged by a solar harvester. We aims to find the optimal bandwidth allocation policy in order to enhance the network performance in terms of user satisfaction and energy efficiency under energy harvesting and bandwidth sharing constraints. Since the arrivals of harvested energy and traffic requests are unknown due to users’ mobility and stochastic request generation, it is necessary to design a learning framework for the controller in order to predict these dynamics through interaction with the environment. For this purpose, we first formulate the resource allocation problem as the framework of a Markov decision process, and then, we employ an actor-critic algorithm to find the optimal policy under which the controller can effectively allocate the limited bandwidth to the SBSs for their data transmissions. We evaluate the performance of the proposed scheme through comprehensive simulations with different settings, and show that the proposed bandwidth allocation scheme can enhance the network’s performance in the long run.

Impact of Small Cells Overlapping on Mobility Management

The mobility management will be more complex and will have a great impact on the quality of service in the future cellular networks, as these networks will have to handle a huge number of user equipments (UEs) and their frequent hand offs due to very dense short-footage small cells. This paper presents a framework to model and derive the coverage of small cells, the cell sojourn time, and the hand off rate in multi-tier small cell networks. The distribution of the small cells around a reference UE’s path is studied by taking into consideration the overlaps among the small cells. Two types of hand off rates are introduced to estimate the load managed by different cells, where inter-frequency hand off rate and intra-frequency hand off rate represent the fraction of hand offs managed by the first tier and the other tiers, respectively. Our analysis shows that ignoring the overlaps among the small cells affects the accuracy of the results significantly. The simulation results validate the accuracy of the analytical results and also show the impact of different parameters, such as the small cell density, the number of tiers and the size of the small cells on the small cell sojourn time, the macro cell sojourn time, and the hand off rate.

Handoff in Various Mobile Network Technologies

Mobile cellular networks are an indispensable part of modern life, where the need for customer satisfaction in the use of many different services by consumers is constantly increasing. The requirements for higher transmission speed, lossless transmission, reliability, efficiency, low latency, mass connectivity, guarantee of high Quality of Service criteria are repeatedly increasing. All this requires the continuous development of the used technologies as well as the introduction of new generations of networks. Handover mechanism is extremely important in cellular network because of the cellular architecture employed to maximize spectrum utilization. To ensure the quality of service in wireless cellular networks, the report proposes the use of a Horizontal Handoff Priority Scheme. Simulation experiments have been carried out, the probability parameters of the scheme have been evaluated and the probabilities of losses occurrence have been classified as rare events. The proposed material are various algorithms and techniques for the implementation of Vertical and Horizontal Handoff in 3G, 4G and fifth-generation networks to provide the required QoS for mobile users with Ultra-High Definition.

Joint Base Station Clustering and Beamforming for Non-Orthogonal Multicast and Unicast Transmission With Backhaul Constraints

The demand for providing multicast services in cellular networks is continuously and fastly increasing. In this work, we propose a non-orthogonal transmission framework based on layered-division multiplexing (LDM) to support multicast and unicast services concurrently in cooperative multi-cell cellular networks with limited backhaul capacity. We adopt a two-layer LDM structure where the first layer is intended for multicast services, the second layer is for unicast services, and the two layers are superposed with different beamformers. Each user decodes the multicast message first, subtracts it, and then decodes its dedicated unicast message. We formulate a joint multicast and unicast beamforming problem with adaptive base station clustering that aims to maximize the weighted sum of the multicast rate and the unicast rate under per-BS power and backhaul constraints. To solve the problem, we first develop a branch-and-bound algorithm to find its global optimum. We then reformulate the problem as a sparse beamforming problem and propose a low-complexity algorithm based on convex-concave procedure. Simulation results demonstrate the significant superiority of the proposed LDM-based non-orthogonal scheme over orthogonal schemes in terms of the achievable multicast-unicast rate region.

RSRP difference elimination and motion state classification for fingerprint-based cellular network positioning system

In recent years, the widespread availability of wireless communication has stimulated research of positioning service for cellular networks. Based on the minimization of drive-test introduced in 3GPP R10, it not only can be used to collect radio measurements and associated location information for network performance assessment, but also be used to build radio map for the fingerprint-based cellular network positioning system. However, due to the UE diversity, reference signal receiving power (RSRP) difference seriously degrades the positioning performance. In addition, UE motion changes the fingerprint length, which leads to fingerprint misalignment. Therefore, in this paper we propose to use multi-dimensional scaling algorithm to eliminate UE RSRP difference. By analyzing the relative RSRP difference of each pair of UE, we can eliminate RSRP difference in both offline and online. We also use the pattern recognition theory to classify UE motion for fingerprint alignment. We separated RSRP into two groups according to the UE motion state. The two groups of fingerprints are classified separately in offline and online. We implemented the proposed method in a real urban area and evaluated its positioning performance. The experiment results indicated our method can achieve a better positioning performance in cellular network positioning system.

Network Coding Aided Collaborative Real-Time Scalable Video Transmission in D2D Communications

There has been an increasing demand for providing real-time video streaming services in the next-generation cellular networks. To improve the quality of such services without additional infrastructure, neighboring devices can recover missing packets by using network coding aided collaborative transmission via device-to-device (D2D) communication. However, most existing work in this area had not considered the issue of how to schedule such coding aided collaborative transmissions effectively for supporting real - time scalable video applications in such environment. In this paper, we study how to improve the quality of real-time scalable video services by efficiently scheduling coding aided collaborative transmissions. We first formulate the problem of optimal collaborative transmission scheduling that determines the optimal transmitting sequence and coding pattern at each transmitting device, which is shown to be NP-hard. To address this problem, we propose a new weight function for measuring the quality of a coding pattern by considering packet recovery gain and potential video decoding gain at receivers. Based on this new weight function, we propose a low complexity centralized algorithm using global state information and an efficient distributed mechanism supporting localized operations in dynamic environment. We deduce their computational complexities. Simulation results verify that the proposed solution outperforms the representative work in the literature.

ANALYSIS OF VOIP TRAFFIC SERVICE IN 4G LTE CELLULAR NETWORKS

Background: In these days, Voice over Internet Protocol (VoIP) technology is in great demand because one cannot bear delay in voice communication. To present the services of VoIP in Long Term Evolution (LTE) systems with appropriate services of quality, it is obligatory to investigate the effectiveness of such administrations and advance the system parameters. Objectives: To study and review 4G LTE cellular networks; to analyze the performance of VoIP throughput in 4G LTE cellular networks by incorporating voice codecs and to evaluate the VoIP latency, and jitter in 4G LTE cellular networks inside voice codecs. Methods / Analysis: The projected study highlighted the examination of VoIP traffic service in 4G LTE cellular networks, using three Quality of Service (QoS) parameters; throughput, latency, and jitter by contrasting the value with three promising voice codecs (G.711, G.729, and EVS). The metrics performance was measured using simulation tool NS2. After running TCL scripts for different network scenarios trace files are formed. These trace files are so large in size and occupy more memory space. The PERL scripts are used to extract these trace files. Results achieved from simulations have been plotted on graphs with the help of MS-Excel. Findings: The overall performance analysis of VoIP traffic carrier has been analyzed by way of comparing three different codecs (G.711, G.729, and EVS) in three different network scenarios based on three key performance indicators: Throughput, Latency, and Jitter by varying the network density and varying call load. Results achieved from simulations demonstrate how a number of performance metrics such as throughput, latency, and jitter are affected by change in factors like number of nodes, voice codecs, distance between BS and SS. With all these conclusions and considering the different scenarios under which the graphs have been plotted, Environmental Studies (EVS) codec is better than other codecs in terms of higher throughput, lower latency, and lower jitter over VoIP traffic in LTE networks by stabilizing the quality of service requisites for multimedia services. Novelty / Improvement: Earlier, the overall efficiency of VoIP changed into measured over the 3G systems. On the other hand, currently there is a need to suit the necessities for higher-speed data. Thus, new standards are intended to meet these prospects that led to the promising of LTE systems. In this study, LTE module is patched with NS2 that is not supported or included by default in NS2. Another novelty is the use of EVS voice codec that is launched as a result of 3GGP. EVS codec is compared with other voice codecs such as G.711, G.729. After all, it is suggested that EVS codec is better than other codecs when using multimedia services. Keywords: EVS, LTE, VoIP, G.711, G.729

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

QUEUEING MODEL FOR SOFT HANDOFF ANALYSIS IN CDMA BASED WIRELESS CELLULAR NETWORK

The most important feature of the mobile network is mobility. Good and continuous service in cellular mobile network can be achieved by using the procedure of handoff (or handover) from one cell to another. Soft handoff is very important feature of cellular Code Division Multiple Access (CDMA) system. In CDMA system a mobile stations (MSs) within a soft handoff region use multiple radio channels and receive their signals from multiple base stations simultaneously. In CDMA cellular system, all cells can also share the same frequency. During handoff procedure, the signaling and voice information from multiple base stations are combined at the mobile switching center (MSC). During the handoff procedure, voice and signaling information must be sent to multiple base stations and the mobile station must combine the results. Within the overlapping area (which is developed by the adjacent cells) of cells, a handset can connect to multiple base stations. In this research paper, a new soft handoff scheme for CDMA cellular network is proposed and investigated. Here we introduce the concept of overlap region between adjacent cells and develop an analytical model for soft handoff in CDMA system. In developed soft handoff model, the balking and reneging behaviors of handoff calls have also considered. Different performance measures of the soft handoff model have developed.

MOBILE PHONE REGULATION: THE EFFECTS OF PROHIBITING HANDSET BUNDLING IN FINLAND

Vertical restrictions have theoretically ambiguous efficiency effects. Marketplace evidence is, therefore, required to reveal the presence of anticompetitive foreclosure. The bundling of mobile phones with cellular network service offers one such market test. One EU member, Finland, prohibited tying arrangements for mobile service and mobile handsets in wireless broadband markets, and then cleanly ended this prohibition in April 2006. We compare the growth in Finnish third-generation (3G) uptake against other European markets using quarterly data from first quarter 2006 through fourth quarter 2012. An output effects model adjusting for market-specific factors suggests 3G penetration growth in Finland increased substantially following market reform.

Improved Quality of Service for Video, Data and Voice Integrated Wireless Cellular Networks through the Queue Dynamic Channel Reservation Scheme

Improved Quality of Service for Video, Data and Voice Integrated Wireless Cellular Networks through the Queue Dynamic Channel Reservation Scheme

Protecting Download Traffic from Upload Traffic over Asymmetric Wireless Links

Many varied mobile device networks have been developed with the advancement of communication and network technologies. Cellular data networks are currently the most widely used, and the number of cellular network subscriptions has increased steadily. Most recent wireless access technologies employ asymmetric uplinks and downlinks because mobile subscribers usually download contents from the Internet. Therefore, most cellular network service providers allocate more bandwidth to downlinks than uplinks for mobile subscribers. However, this asymmetry can have unexpected influence on network performance, particularly TCP performance. When the uplink interface is congested, TCP ACK packets are delayed by TCP data packets on the uplink, causing considerable TCP retransmissions on the downlink channel. Thus, downlink bandwidth cannot be fully utilized, which results in significantly degraded downlink throughput. To resolve this problem, this paper proposes a feedback scheme, network traffic chunk regulator (NCR). We analyzed the aforementioned problem through the empirical study, and we designed and implemented NCR based on the analysis. NCR adaptively controls TCP according to the degree of link usage asymmetry. We evaluate NCR performance through simulations and experiments with real devices. We verify that the proposed scheme allows the downlink traffic to not interfere with the aggressive uplink traffic. Thus, NCR increases total link utilization and aggregated throughput significantly, without imposing additional overhead on base or mobile stations.

A Novel D2D Communication Scheme for Location-Based OTT Service in Cellular Networks

A Novel D2D Communication Scheme for Location-Based OTT Service in Cellular Networks