Long Term Evolution Networks Research Articles

Enhanced LAA for Unlicensed LTE Deployment Based on TXOP Contention

Licensed-assisted-access (LAA) has recently emerged as a heterogeneous network technology to help mitigate the scarcity of licensed spectrum by extending the long-term evolution (LTE) network to unlicensed spectrum. This work proposes an enhanced LAA (eLAA) as a practical technique by exploiting the inherent transmit opportunity (TXOP) reservation via the Clear-to-Send-to-Self (CTS-to-Self) frame in Enhanced Distributed Channel Access (EDCA) to seamlessly integrate eLAA transmission within existing WiFi protocol. Unlike other LAA proposals, our eLAA is non-intrusive to unlicensed WiFi users and beneficial to both eLAA and WiFi networks. To further improve throughput, we analyze and derive an optimized unlicensed resource allocation scheme before deriving several intrinsic properties. Our results demonstrate that tagging CTS-to-Self frames as a higher-priority access category can substantially improve eLAA throughput without seriously degrading the per-user WiFi throughput.

A compendious study of device-to-device communication underlaying cellular networks

Device-to-device (D2D) communication is recognised as an emerging technology used in the cellular networks with many advantages such as peer-to-peer (P2P) services, higher spectral efficiency, enhanced throughput and higher data transmission capacity for the fourth generation (4G) and beyond cellular networks. To attain the rising demands of the cellular users, there is always a need to enhance the network transmission capacity of cellular networks. In Long-Term Evolution (LTE) and LTE-Advanced (LTE-A) networks, the study of D2D communications is being interested in academia, industry person and standardisation bodies. In near future, there will be billions of connected user equipment. The next generation networks (NGNs) that to be heterogeneous in nature and demanding higher data rates, lesser delays, enhanced system transmission capacity and better throughput with large coverage. As accessible licensed spectrum assets are limited and for the survival of mobile network operators, it is required to facilitate users as per their rising demands. This survey paper explores the detailed literature of D2D communication for cellular network including their classification based on spectrum used, comparison with other short-distance wireless communication technologies, mobile data traffic growth prediction, advantage and disadvantages, applications and the open issues with work done so far.

Measurements and Analysis of Short-Term Fading Behavior in High-Speed Railway Communication Networks

This paper presents the analysis of short-term fading behavior in high-speed railway (HSR) communication networks, based on passive channel measurements. A long-term evolution (LTE)-based channel sounding system is used to measure the propagation characteristics in a dedicated HSR LTE network with multiple scenarios, such as rural, station, and suburban, and with the echo channel effect (ECE) caused by the same signaling from different remote radio units. The measurement data are partitioned into four cases, involving rural, rural with the ECE, station, and suburban, aiming to investigate the impact of two factors, e.g., the scenario and the ECE, on the propagation characteristics. Based on the processed data, the short-term fading behavior is characterized in terms of the fading severity and the time-frequency-space dispersion in the four cases. The distance-dependent models and statistical models of Ricean K-factor, delay spread, Doppler spread, and angular spread are proposed and compared with previous paper. The presented results will be useful in time-frequency-space channel modeling for future HSR mobile communication systems.

Improving the eNodeB Coverage of a Bad Spot Area by Using A Relay Node

The quality of LTE (Long Term Evolution) network in WR Supratman Street, Bandung is categorized as quite bad as shown by the average RSRP (Reference Signal Receive) and SINR (Signal to Interference Noise Ratio) values of -101.30 dBm and 2.43 dB, respectively. Both parameters are below the standard operator with the average RSRP and SINR standard values of -101.30 dBm and 2.43 dB, respectively. The previous field measurement indicated that the area belonged to a bad spot area caused by shadowing buildings. This study used the node scheme of decode and forward and physical mode of inband relay node with the aim of extending the eNodeB coverage. By applying this technique, the average RSRP value increased by 18% and the average SINR value increased by 53%. Based on the RF (Radio Frequency) parameters, the average RSRP value with samples below the -85 dBm standard improved by 81%, while the average SINR value with samples below 5 dB improved by 45%.

Neural embedded smart link generation scheme for heterogeneous network

The Long Term Evolution (LTE) network is a very much popular network in heterogeneous network. Heterogeneous networks provide maximum data rate by integrating various technologies and channels, based on appropriate network selection. For the sensible data transmission in the LTE network, noise plays an vital role as channel is a free space. The minimum noise channel selection is a decision of present and previous status of network channel. Proposed scheme develop neural network model, which will act as a smart link generation scheme for computing minimum noise channel path for sensible data transmission. Hence, proposed scheme will improve performance of the network. Result indicates that, proposed scheme improves throughput and system reliability. Proposed scheme is also reduces packet loss rate and energy consumption in contrast with conventional techniques.

Fair-QoS Broker Algorithm for Overload-State Downlink Resource Scheduling in LTE Networks

Efficiently scheduling various service classes while fulfilling performance targets is one of the main challenges in 3GPP Long-Term Evolution (LTE) communication systems. However, Quality of Service (QoS) and fairness provisioning for all different service classes are generally unstable due to insufficient radio resources, especially in heavily loaded states of the network, which leads to the deterioration of overall system performance. In this paper, we address these challenging issues by proposing a two-level downlink scheduling algorithm to deliver all traffic types while attempting to provide a compromise for the LTE performance targets. For the higher level of the algorithm, a coherent resource distribution approach is developed by applying a game theory model in a nested manner to provide per-class fairness. At the lower level, the greedy-knapsack algorithm is properly tailored to optimally allocate resources to the best potential bearers for QoS and throughput enhancement. The performance of the proposed algorithm was evaluated for normal and overload states of the network. The simulation results clearly demonstrate that the proposed scheduling algorithm, compared with the reference scheduling algorithms, provides the best tradeoff for fairness, throughput, and QoS performance in terms of packet loss rate and packet latency for different service classes.

Performance Optimization on Dynamic Adaptive Streaming over HTTP in Multi-User MIMO LTE Networks

Recent years have witnessed the emergence and ongoing proliferation of dynamic adaptive streaming over HTTP (DASH 1), which reuses web servers with HTTP communication instead of relying on RTSP/RTP/RTCP-based media server and promises to be capable of automatically tuning to bandwidth dynamics. Aware of its excellent performance, the third generation partnership project (3GPP) long term evolution (LTE) has adopted DASH (with specific codecs and operating modes) for use over mobile wireless networks in order to realize ubiquitous multimedia delivery. In a multi-user multiple-input-multiple-output (MU-MIMO) LTE system, spatial multiplexing gain can be achieved by making sure the transmitter to deliver distinct data streams to multiple receivers simultaneously, which provides the choices to opportunistically schedule the preferred receivers each time for a common time-frequency resource. In such a system, one of the major challenges to enhance DASH performance is to design an effective scheduler that can fully enjoy the benefit of spatial reuse as well as guaranteeing satisfactory video services for all users. To this end, in this paper, we propose a utility maximization framework (UMF) for DASH application delivered over MU-MIMO LTE downlinks. In particular, we characterize DASH performance by a combined utility function in terms of average video rate, playback buffer status, and battery energy state. Correspondingly, we develop a utility-based scheduler that selects multiple user equipments (UEs) to share each common network resource under the consideration of precoding-based MU-MIMO links in order to maximize system-wide DASH performance. We prove the NP-hardness of the scheduling problem and propose a priority search algorithm to provide time-efficient solution. We further incorporate novel rate adaptation on the application layer for the scheduled UEs to dynamically set the requested encoding bitrates to explore the balance between agile responsiveness and shifting smoothness. Extensive system-level simulations with realistic video trace validate the effectiveness of our framework in terms of rate adaptability, playback buffer depletion percentage, and battery energy saving.

Statistical validation of an LTE emulation tool using live video streaming over reliable transport protocols

Multimedia services such as Live Video-Streaming (LVS) or Video on Demand are the main drivers behind the notable traffic growth in cellular networks. This fact has attracted the interest of both academia and telcos in improving the end user’s quality of experience. For this reason, the development of test benches for conducting traffic studies in this type of telecommunication system is necessary and emulators are a good option to validate possible solutions without affecting the real systems. However, most works addressing the emulation of Long-Term Evolution (LTE) systems do not validate their outcomes with real environments and hence ignore critical parameters such as the impact of wireless propagation under different scenarios. Therefore, the goal of this paper is to validate an outdoor propagation model for LVS so that accurate studies of traffic characterization in LTE networks can be carried out using an emulation tool. The validation is done through a statistical analysis of variance (ANOVA) of Quality of Service metrics, comparing the results obtained in an LTE-emulated scenario with those obtained in a real LTE test bench. For this study, the LVS service runs on top of a reliable transport protocol. Specifically, we test the Real-Time Message Protocol and the MPEG Dynamic Adaptive Streaming over HTTP (DASH) protocol, both using TCP at the transport layer. According to the results, the propagation model that better matches the real environment under the considered conditions is the Nakagami-m propagation model with m = 5.

Performance Enhancement of Multi-Antenna Relay Link in LTE Het-Net

In this paper, the relay link performance for an Amplify and Forward (AF) multi-antenna relay based heterogeneous LTE (Long Term Evolution) network is enhanced with two novel techniques, the Golden codes and Error Vector Magnitude (EVM) based Constellation Combiner (ECC). The performance evaluation of the proposed co-operative LTE Het-Net is done in a real time indoor environment using Wireless open Access Research Platform (WARP). The proposed techniques for the LTE Het-Net are compared with traditional Alamouti Scheme with Maximal Ratio Combing (MRC). From the obtained results it is seen that the LTE network with proposed techniques gives a 12% improvement in EVM than the conventional LTE network.

QoE-Driven Joint Optimization of Segment Adaptation and Resource Allocation for DASH Clients Over LTE Networks

In this paper, we focus on a comprehensive dynamic adaptive streaming over HTTP (DASH) framework, which consists of video content analysis at the HTTP adaptive streaming server, joint optimization of segment switch and resource allocation at eNodeB, and playback information extraction at the client, to improve the quality of experience (QoE) of the DASH clients over long-term evolution networks. We explore the unique characteristics of each segment by establishing the size-time and size-distortion models based on the video packet information extracted from the encoder rather than modeling the entire video sequence by a fixed function. Video quality, stability, and playback continuity can be predicted and reflected by these constructed models. Considering the above three factors, we develop an accumulative QoE model by calculating and predicting the QoE factors of each segment. Then, the entire framework is formulated as a mixed-integer non-linear programming mathematical model to maximize the total QoE of the DASH clients, where decisions on resource allocation and video segment switch are jointly optimized in a semi-synchronous centralized mode. Resource allocation consists of resource block assignment and modulation and coding scheme selection rather than only determining the resource utilization percentage. To perform the optimization, we develop a low-complexity heuristic algorithm that decomposes the original problem into multiple subproblems. The simulation results show that our proposed algorithms can efficiently improve the QoE level compared with other existing algorithms.

LWA Rate Adaption by Enhanced Event-Triggered Reporting

Unlicensed spectrum has been utilized to open up additional capacity to support long-term evolution (LTE) service. LTE and wireless local area network (WLAN) Aggregation (LWA) is a perfect solution that satisfies this need. In 2017, Taiwan has deployed the first commercial LWA service. The deployed LWA network reuses and is nicely merged with the existing individual LTE and WLAN networks. To provide appropriate WLAN transmission bandwidth, the user equipment periodically measures the WLAN quality and reports the results to the eNB (the LTE base station). The eNB then decides if the transmission rate should be adapted. We investigate the performance of periodical reporting and then propose the enhanced event-triggered reporting to improve the performance of WLAN transmission rate adaption. We suggest how to select appropriate frequency to minimize the network traffic of periodical reporting. We also show that enhanced event-triggered reporting outperforms periodical reporting. Our solution utilizes the standard 3GPP protocols and does not modify the mobile phone's software.

A novel random access scheme for stationary machine‐type communication devices

The long term evolution (LTE) cellular network, primitively designed for human-to-human communications, is attracting more and more attention in machine-to-machine communication scenarios. However, when a massive number of machine-type communication (MTC) devices require access to the network simultaneously, the existing random access mechanism in LTE networks will inevitably suffer from severe congestion. In order to address this problem for stationary MTC devices, the authors propose a novel random access scheme. In the proposed scheme, an alleviating-collision based timing-advance selection (ACT A S) algorithm is designed where, aided by a special preamble placement method, the eNodeB (eNB) can estimate the number of contenders with different timing advance (T A ) indices. According to the estimated results, the eNB can choose the T A index to be contained in the random access response information. In addition, they further analyse the number of MTC devices which could successfully access the network in each random access slot. The simulation results prove the accuracy of the throughput analysis as well as the remarkable performance of the proposed random access scheme in terms of the number of required slots to serve all the devices.

OPTIMASI JARINGAN 4G LTE (LONG TERM EVOLUTION) PADA KOTA BALIKPAPAN

Long Term Evolution (LTE) merupakan teknologi generasi ke empat (4G) yang dikembangkan oleh 3rd Generation Partnership Project (3GPP). LTE mampu memberikan kecepatan downlink sampai dengan 100 Mbps dan uplink 50 Mbps. Penelitian ini mempunyai tujuan untuk melakukan perancangan jaringan 4G LTE pada wilayah kota Balikpapan dengan target khusus untuk mengetahui kualitas perancangan jaringan 4G LTE di kota Balikpapan melalui parameter best signal level, nilai C/ (N+I), throughput, RSRP dan BLER dari perancangan yang telah dilakukan. Metode penelitian dilakukan melaui survey ke lokasi site-site e Node yag diperlukan untuk memperoleh gambaran langsung kodisi sekitar e Node B dilanjutkan proses plotting 126 site-site e Node B di wilayah kota Balikpapan kemudian yang dilanjutkan dengan proses simulasi perancangan jaringan menggunakan software Atoll. Dari hasil simulasi ini dapat diketahui kualitas perancangan jaringan 4G LTE kota Balikpapan dengan nilai-nilai parameter yang diinginkan seperti best signal level sebesar -69,72 dBm, nilai C / (N+I) sebesar 5,08. Untuk perfomansi throughput sebesar 11.8034 kbps, sedangkan nilai RSRP sebesar -115, 88 dBm serta nilai BLER sebesar 0,03 .

Multicast Resource Allocation with Opportunistic Scheduling in LTE Networks

Long Term Evolution (LTE) and beyond networks offer high bitrates with low latencies which makes them the best choice to handle the growing demand on multicast mobile services such as video streaming, and news broadcasting. In Conventional Multicast Scheme (CMS), the gain of multicast is exploited by transmitting data to all users simultaneously using the rate of Worst Channel Gain (WCG), which wastes network resources. In this paper, to better balance the tradeoff between the multicast gain and multiuser diversity, we propose a mechanism to select a threshold to split users into two subgroups and exploits the Opportunistic Multicast Scheme (OMS) to transmit the data. Simulation results show that the proposed mechanism improves the multicast performance in terms of increased throughput, decreased delay and Packet Loss Ratio (PLR) compared to existing mechanisms from the literature.DOI: http://dx.doi.org/10.5755/j01.eie.24.5.21850

Wireless technologies and policies for connecting rural areas in emerging countries: a case study in rural Peru

PurposeThis paper aims to compare the costs of deploying different wireless terrestrial broadband technologies in the Andes and Amazon Regions of Peru. These areas are representatives of different and challenging geographic regions throughout the globe that currently are severely underserved or unserved for vital broadband services necessary to bridge the “Digital Divide”.Design/methodology/approachThe broadband technologies studied include Wi-Fi, Worldwide Interoperability for Microwave Access (WiMAX), long term evolution (LTE), TVWS and new stratospheric platforms (super-pressure balloons). This study conducts a technical analysis (design and simulation) of wireless broadband networks, and a bottom-up engineering cost analysis to estimate and compare the deployment and operating costs of the networks over a 10-year period. The analysis also identifies potential regulatory barriers to deployment associated with spectrum allocation licenses and overbooking requirements intended to improve quality of service.FindingsComparison of the capital and operating expenses of these options over a 10-year period finds that LTE and Wi-Fi can be the lowest cost alternatives, though significantly, stratospheric balloons have the lowest initial costs for the first few years and can factor as a low-cost broadband catalyst early in deployment. Finally, the lowest cost technology broadband roadmap for the 10-year period is presented, which includes using stratospheric balloons (carrying micro-LTE base stations) for the first years and deploying complementary terrestrial LTE networks for the rest of the 10-year period.Originality/valueThis study presents detailed technical and engineering cost analysis results of wireless access network deployments, including advanced wireless technologies and new unmanned aerial systems, to expand broadband services to rural areas in mountainous (Andes Region) and rainforest (Amazon Region) geographies to reduce the digital divide in emerging countries. Results aim to aid governments, regulators, internet service providers (incumbents and competitive) and content providers to assess current alternatives to expand broadband service in these rural areas.

Scheduling algorithm for the LTE downlink with F-OFDM using adaptive multifractal envelope process and minimum service curve

In this work, first we propose an adaptive algorithm to estimate the parameters of a multifractal model in the wavelet domain to describe network traffic flows. Further, we propose an envelope process for network traffic flows based on the adaptive estimation of the modeling parameters in order to guarantee quality of service (QoS) in LTE (Long Term Evolution) networks. The proposed envelope process is compared to the main traffic model based envelope processes known in the literature. In LTE networks, Adaptive Modulation and Coding (AMC) technique is used for adjusting the modulation order and code rate based on the user channel state information in order to achieve a Block Error Rate (BLER) lower than 10%. In this work, we investigate the use of F-OFDM multi-carrier modulation, which is one of the candidates for 5 G networks. To this end, simulations of the LTE downlink are carried out using OFDM (Orthogonal Frequency-Division Multiplexing) and F-OFDM (Filtered Orthogonal Frequency-Division Multiplexing) multi-carrier modulation with the objective of mapping the BLER as a function of SNR (Signal-to-Noise Ratio). We also propose an algorithm for allocating resources in the LTE downlink that makes use of the proposed multifractal modeling based adaptive envelope process. The proposed scheduling algorithm aims to improve some network parameters while guaranteeing a maximum delay to the user by considering the following information: backlog, channel condition and user traffic behavior. In order to estimate the maximum network delay, we propose an adaptive minimum service curve for the LTE network that can be used for admission control purposes. The performance of the proposed scheduling algorithm is compared to those of several scheduling schemes known in the literature through computational simulations of the LTE downlink.

Proposing packet-key based end-to-end security architecture for the post-LTE networks

Abstract This paper proposes the end-to-end security scheme with packet key mechanism to perform ciphering of user traffic between two User Equipments (UEs) attached to the different Long Term Evolution (LTE) networks. In LTE system, each UE derives its master key after a mutual authentication is performed between the UE and its local LTE network. In this paper, two end-to-end UEs use their own master keys to generate real-time packet keys where different packet keys are applied to encrypt packet stream data on a packet basis. Because the life cycle of the packet key is same as a packet period, the proposed security scheme significantly improves the security strength for end-to-end LTE users. This paper also analyzes the security strength of the proposed packet key system as well as the degree of latency for the session initialization, real-time packet encryption, and real-time packet decryption.

VANET–LTE based heterogeneous vehicular clustering for driving assistance and route planning applications

The Internet of vehicles incorporates multiple access networks and technologies to connect vehicles on roads. These vehicles usually require the use of individual long-term evolution (LTE) connections to send/receive data to/from a remote server to make smart decisions regarding route planning and driving. An increasing number of vehicles on the roads may not only overwhelm LTE network usage but also incur added cost. Clustering helps minimize LTE usage, but the high speed of vehicles renders connections unstable and unreliable not only among vehicles but also between vehicles and the LTE network. Moreover, non-cooperative behavior among vehicles within a cluster is a bottleneck in sharing costly data acquired from the Internet.To address these issues, we propose a novel destination- and interest-aware clustering (DIAC) mechanism. DIAC primarily incorporates a strategic game-theoretic algorithm and a self-location calculation algorithm. The former allows vehicles to participate/cooperate and enforces a fair-use policy among the cluster members (CMs), whereas the latter enables CMs to calculate their location coordinates in the absence of a global positioning system under an urban topography. DIAC strives to reduce the frequency of link failures not only among vehicles but also between each vehicle and the 3G/LTE network. The mechanism also considers vehicle mobility and LTE link quality and exploits common interests among vehicles in the cluster formation phase. The performance of the DIAC mechanism is validated through extensive simulations, whose results demonstrate that the performance of the proposed mechanism is superior to that of similar and existing approaches.

Network Quality Measurements of LTE Drones

Cellular-connected drones can provide beyond line-of sight control (BVLOS), low latency, real time communication, robust security, and wide range coverage. Cellular-connected drones have several key potential applications in enhanced LTE and 5G networks. The objective of the study is to evaluate field measurement data collected during drone flights in the KT Long-Term Evolution (LTE) networks in Seoul and Jeju, Korea. The multicopter drones are developed with LTE modem and LTE test smart phone for field measurements. The radio network quality between drones and LTE base transceiver stations (BTS) is evaluated by measuring downlink metrics such as the serving cell RSRP, RSRQ, SINR, modulation types of downlink, the downlink and uplink throughputs, and LTE PUSCH Tx Power on reference signal. In the existing LTE networks, field measurements show that there is no problem in C&C of BVLOS operations in the flight height up to 150m but the data rate requirements for video transmission does not meet at high flight altitudes.

Analytical Model for Estimating the Impact of Changing the Nominal Power Parameter in LTE

UpLink Power Control (ULPC) is a key radio resource management procedure in mobile networks. In this paper, an analytical model for estimating the impact of increasing the nominal power parameter in the ULPC algorithm for the Physical Uplink Shared CHannel (PUSCH) in Long Term Evolution (LTE) is presented. The aim of the model is to predict the effect of changing the nominal power parameter in a cell on the interference and Signal-to-Interference-plus-Noise Ratio (SINR) of that cell and its neighbors from network statistics. Model assessment is carried out by means of a field trial where the nominal power parameter is increased in some cells of a live LTE network. Results show that the proposed model achieves reasonable estimation accuracy, provided uplink traffic does not change significantly.