Deployment Of Long Term Evolution Research Articles

Enhancing LTE Network Performance through Optimized Integrator Handover Algorithm

In the landscape of Long-Term Evolution (LTE) networks, handover algorithms play a pivotal role in maintaining uninterrupted service quality during user mobility. This study revisits the Integrator Handover Algorithm, initially analyzed in previous research, focusing on its optimization in response to the evolving challenges in modern LTE networks. We delve into identifying the inefficiencies of the current algorithm and propose enhancements aimed at improving handover success rates and minimizing latency. Our methodology encompasses a comprehensive literature review, empirical data analysis from contemporary LTE deployments, and a simulation-based approach for algorithm refinement. The outcome is an evolved Integrator Handover Algorithm that is better suited to the high traffic volumes and diverse user behaviors in current LTE network scenarios.

Heterogeneous SDN controller placement problem—The Wi-Fi and 4G LTE-U case

The widespread deployment of 5G wireless networks has brought about a radical change in the nature of mobile data consumption. It requires the deployment of Long Term Evolution to the unlicensed spectrum (LTE-U) to alleviate the shortage of available licensed spectrum while Wi-Fi is the most dominant radio access technology in the unlicensed spectrum. This has led to suggestions concerning the coexistence of multi radio access technologies such as Wi-Fi and LTE-U. Clearly, Software Defined Networks (SDN) can utilize the LTE-U radio bandwidth efficiently. The SDN paradigm decouples the network’s control logic from the underlying routers and switches, which promotes centralization of network control. The controller placement problem is crucial to SouthBound interface optimization and involves the location of the controllers, their number and the assignment function of switches to controllers. In this paper, a novel strategy is presented to address the wireless controller placement problem, which improves the throughput, link failure probability and the transparency on the SouthBound interface in cases where hybrid providers choose either LTE-U or Wi-Fi as link layer technologies. The problem of determining the placement of LTE-U and Wi-Fi based controllers is modeled and two heuristic solutions are proposed. Simulations show that the proposed algorithms provide a fast and efficient solution.

Market Competition Between LTE-U and WiFi

LTE-U is an extension of the Long Term Evolution (LTE) standard for operation in unlicensed spectrum. LTE-U differs from WiFi, the predominant technology used in unlicensed spectrum in that it utilizes a duty cycle mode for accessing the spectrum and allows for a more seamless integration with LTE deployments in licensed spectrum. There have been a number of technical studies on the co-existence of LTE-U and WiFi. In this paper, we instead investigate the impact of such a technology from an economic perspective. We consider a model where an incumbent service provider (SP) deploys a duty cycle-based technology like LTE-U in an unlicensed band along with operating in a licensed band and competes with one or more entrants that only operate in the unlicensed band using a different technology like WiFi. We characterize the impact of a technology like LTE-U on the market outcome and show that the welfare impacts are subtle, depending in part on the amount of unlicensed spectrum and number of entrants. The difference in spectral efficiency between LTE and WiFi also plays a role in the competition. Finally, we investigate the impact of the duty cycle and the portion of unlicensed spectrum used by the technology.

A 4G LTE Evolved packet Core Planning and Deployment in Freetown Sierra Leone

Wireless broadband subscribers have tripled in the past two decades in the world. It subsequently adds more burden on the network traffic, thereby pressuring the current 2G / 3G wireless network infrastructural development in Freetown, Sierra Leone. The existing 2G / 3G network infrastructures in Freetown offer limited resources for download and upload speed of 12.54Mbps and 2.59Mbps, respectively, to active subscribers. The exponential increase in the country’s population has adverse effects on the subscriber’s database. Therefore, a considerable task is faced by the country’s telecommunication network infrastructures to devise an improvement and efficient technologies to augment the current system to handle the numerous issues. Three active private mobile network operators (X, Y, & Z) and one Government-owned operator (W) exist in the country. The only operator that runs across the country is operator X, and it has the highest number of subscribers. The country has just rollout it Long Term Evolution (LTE) by the private MNOs.
 The research is to encourage the Sierra Leone National Telecommunication Commission (NATCOM), a telecommunication regulatory body, to mandate all MNOs in the country to roll out the 4G LTE core network infrastructure in Freetown. ARIMA model is used to analyze the throughputs (kbps) prediction to ascertain 4G LTE rollout using the Python programming language is an effective alternative. Statistical data from operator X for ten years for Freetown municipality from January 2010 - November 2019 was collected. The research concludes that 4G LTE deployment or upgrade was necessary for the Freetown municipality.

Towards Fair and Efficient Spectrum Sharing Between LTE and WiFi in Unlicensed Bands: Fairness-Constrained Throughput Maximization

The deployment of Long Term Evolution (LTE) networks in unlicensed spectrum is a promising solution to overcome the scarcity of licensed spectrum. Yet it has been widely observed that severe unfairness and performance degradation would occur when LTE coexists with WiFi, the incumbent user of unlicensed bands, without proper adjustment. Fair and efficient coexistence of these two networks thus becomes crucial. It, nevertheless, remains largely unknown how to optimize the total throughput of the LTE and WiFi networks under fairness constraints. To address the above open issue, this paper considers that a WiFi network coexists with an LTE network using the Category 3 or Category 4 Listen-Before-Talk (LBT) mechanism, and aims to characterize the maximum total throughput of the LTE and WiFi networks under two fairness constraints including throughput fairness and 3GPP fairness. The analysis shows that the maximum total throughput is independent of which LBT mechanism the LTE network adopts, and can be improved as the mean successful transmission time of the LTE network increases. Explicit expressions of the optimal initial backoff window sizes to achieve the maximum total throughput under both throughput fairness and 3GPP fairness are also derived, which shed important light on the practical network design. It is found that the initial backoff window size of the LTE network should be enlarged as the mean successful transmission time of the LTE network increases, indicating that for fair and efficient coexistence with a WiFi network, the LTE network needs to access the unlicensed channel infrequently with large packets. To facilitate implementation in practice, distributed schemes are further proposed, with which WiFi and LTE can optimally adjust the backoff window sizes based on their own observation and estimation without the need of coordination between these two networks.

Wi-Fi and LTE-LAA coexistence problems, challenges and features in 5GHz unlicensed bandwidth

The demand for high data rate and stable Quality of Service (QoS) from cellular networks’ subscribers is a huge challenge for cellular operators. To overcome this issue (providing high data rate and stable QoS) it requires more bandwidth. The lack of licensed bandwidth and also its high cost make it hard for operators to overcome this issue. To find a fair solution and expand the capacity of cellular networks, operators started deployment of Long Term Evolution (LTE) in unlicensed bandwidth, exactly utilizing 5GHz unlicensed bandwidth in small cell scenarios. The extension of LTE to the 5GHz unlicensed bandwidth where it is already in used by Wi-Fi will create huge coexistence problems between Wi-Fi and LTE. It results from that Wi-Fi and LTE have different channel access mechanisms. This paper presents the channel access mechanisms of Wi-Fi and LTE-Licensed Assisted Access (LTE-LAA), coexistence problems, challenges, privileges, coexistence features of LTE and Wi-Fi and Finally, we conducted the simulation for LAA based on Listen Before Talk (LBT) mechanism and Wi-Fi to find that how LAA with LBT mechanism is friendly to the Wi-Fi networks when they share the same bandwidth. The simulation results illustrate that LAA based on LBT channel access mechanism by alone cannot bring a fair coexistence between these two technologies, it needs further improvement.

Ergodic capacity analysis and transmission power optimization in D2D underlaying cellular communication

In this paper, we consider a non-cooperative deployment of Long Term Evolution (LTE) and Device-to-Device (D2D) links, for which we derive approximations for Signal-to-Interference and Noise Ratio (SINR) distributions plus ergodic capacity expressions. We show that the capacities of D2D and cellular LTE systems w.r.t. their transmitted power ratios are concave and convex, respectively. We then propose two optimization approaches for the power allocation mechanism. In the particular case of major interference links, the convex concave procedure (CCCP) is proposed to obtain the optimal power ratio that satisfies the target quality of service. In an environment with multiple D2D links, we firstly generalize the CCCP approach and propose a resource association and power allocation algorithm. We then propose a lower complexity optimization approach that exploits the spatial statistics and correlation of the D2D and cellular links based on the Kriging interpolator to estimate the SINR distributions at each location. Finally, we present analytical and numerical results that demonstrate the effectiveness of the introduced algorithms, and we show that there exists an optimal power ratio that satisfies the transmission constraints in both D2D and cellular systems.

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.

Spatial and Time Domain Model for LAA/Wi-Fi Coexistence

In Release 13 of the 3rd Generation Partnership Project standard, the deployment of long-term evolution (LTE)/ LTE-advanced to the unlicensed spectrum called licensed-assisted access (LAA) was introduced to satisfy the high demand of traffic data with a new type of services mostly multimedia streams. The unlicensed spectrum is a shared resource between different radio access terminals such as Wi-Fi and radar system, and listen before talk (LBT) in LTE side makes this coexistence possible. In this letter, we propose a new framework to model and evaluate the performance of LAA/Wi-Fi coexistence based on marked Poisson point process (MPPP) and Markov chain model. The proposed model captures the back-off procedure in the spatial and time domain to provide a more realistic analysis of the channel busy probability and the signal to interference plus noise ratio coverage probability. Numerical results show the validity of the proposed model with the overestimation of the LAA and Wi-Fi nodes density in MPPP model.

MIMO HetNet IEEE 802.11p–LTE deployment in a vehicular urban environment

Intelligent Transportation Systems (ITS) are receiving significant interest due to a wide variety of applications such as road safety, traffic efficiency and infotainment. To satisfy the diverse vehicular application requirements, this paper presents a detailed comparative performance simulation study over IEEE 802.11p, LTE and the proposed Heterogeneous (HetNet) IEEE 802.11p–LTE network for urban environments. Therefore, a hybrid handover algorithm is proposed, combining the IEEE 802.11p-based multihop clustering and the Long-Term Evolution (LTE) networks, with the goal of achieving a high data packet delivery ratio (PDR) and low delay. The COST-231 Walfisch–Ikegami propagation model is evaluated, incorporating 3D antenna radiation patterns measured in an Anechoic Chamber. The performance evaluation analysis is validated through VEINS–OMNeT++ network simulator over several performance metrics such as Throughput, Packet Delivery Ratio, End-to-End Delay and SNIR Lost Packets for a variety of vehicle density and vehicle speed under both SISO and MIMO open loop 2×2 Spatial Multiplexing (SM) scheme antenna techniques respectively. The results indicate that the HetNet 802.11p–LTE network is the most prominent solution in urban environments outperforming both IEEE 802.11p and LTE in terms of delay, reliability, and scalability, whereas LTE offers acceptable performance for sparse network topologies.

Sharing of Unlicensed Spectrum by Strategic Operators

Facing the challenge of meeting ever-increasing demand for wireless data, the industry is striving to exploit large swaths of unlicensed spectrum, which supports open access. Major standards bodies are currently considering a proposal to retool and deploy long term evolution (LTE) technologies in unlicensed bands. This paper studies the fundamental question of how the unlicensed spectrum can be shared by strategic operators to mitigate suffering from the tragedy of the commons. A class of general utility functions is considered. The spectrum sharing problem is formulated as a repeated game over a sequence of time slots. It is first shown that a simple static sharing scheme allows a given set of operators to reach a subgame perfect Nash equilibrium for mutually beneficial sharing. The question of how many operators will choose to enter the market is also addressed by studying an entry game. A sharing scheme, which allows dynamic spectrum borrowing and lending between operators, is then proposed to address time-varying traffic and proved to achieve perfect Bayesian equilibrium. Numerical results show that the proposed dynamic sharing scheme outperforms static sharing, which in turn achieves much higher revenue than uncoordinated full-spectrum sharing. Implications of the results for the standardization and deployment of LTE in unlicensed bands (LTE-U) are also discussed.

Simulated performance of TCP, SCTP, DCCP and UDP protocols over 4G network

Forth Generation (4G) network support for wide geographical locations proves its use as a more advanced wireless technology. The Long-Term Evolution (LTE) is a 4G mobile communications standard set by International Communication Union (ITU), specifically ITU Radio communication Sector (ITU-R). At the moment, video traffic and telecommunications grow under the expansion of LTE, which is considered as the actual motivating access technology of 4G network. Throughout the deployment of LTE, various transport protocols are advised and broadly experimented, for instance, TCP, SCTP, DCCP and UDP that may execute differently on 4G networks subject to the network scenarios and parameter settings. Even though the deployment of LTE is swiftly enhanced, there is a lack of performance evaluation of its protocols. Hence, a widespread scrutiny is required for the evaluation of the operation of numerous protocols for high-end applications such as multimedia. Adopting these applications with flexible quality of service constraints with improved usage of resources is a challenging task. In this paper, the output results of different transport protocols for multimedia streaming applications, e.g., video, through extensive simulations are analyzed. The performance of an MPEG-4 video streaming is evaluated using NS-3. The performance metrics used are delay, jitter, throughput, and packet loss. These metrics are evaluated at the base station via TCP, SCTP, DCCP and UDP protocols over the 4G-LTE technology. The obtained results show that the DCCP performs the best in throughput improvement with the minimization of delay and jitter as compared to UDP, TCP, and SCTP.

Guest Editorial: LTE in Unlicensed Spectrum

The articles in this special section focus on the deployment of Long Term Evolution in unlicensed spectrum. These articles cover various design issues such as network architecture, protocol development, network coexistence, unlicensed spectrum access, and practical implementation. Fifth generation (5G) cellular networks will face a rigorous challenge in the ever increasing data rate requirement. To meet such anticipated data growth demand, the industry and academia have developed many cutting edge techniques to improve spectrum utilization. However, the scarcity of spectral resources is still a fundamental bottleneck for network capacity enhancement. Recently, the rich available bandwidth on the 5.8 GHz unlicensed national information infrastructure (U-NII) spectrum has stimulated substantial interest from cellular operators to use the unlicensed spectrum for LTE. In 2015, the LTE-Unlicensed (LTE-U) Forum formally launched the LTE-U specification, and the Third Generation Partnership Project (3GPP) has pushed the standardization of licensed assisted access (LAA)into its Releases 13 and 14. However, the LTE-U technology is still in its infancy, and there are lots of challenges that need to be solved, such as network coexistence among different radio access technologies, unlicensed spectrum sharing and access, and quality of service (QoS) provision on unlicensed spectrum. This Feature Topic aims to provide a comprehensive overview of this appealing technology, harmonizing recent results and key challenges, as well as highlighting future important directions.

Radar interference into LTE base stations in the 3.5 GHz band

We study the interference from a rotating shipborne radar system that spectrally and spatially coexists with a Long Term Evolution (LTE) cellular communications network in the 3.5 GHz band to investigate the feasibility of LTE deployment in the United States coastal metropolitan cities in that band. First, we simulate the radar systems with realistic operational parameters. Furthermore, we leverage a detailed 3GPP-compliant LTE simulation with a sophisticated air interface modeling and investigate sensitivity of LTE to radar interference in macro cell, outdoor small cell, and indoor small cell scenarios. We simulate the propagation conditions between the radar and LTE system by adopting the Free Space Path Loss and Irregular Terrain Model commonly leveraged by National Telecommunications and Information Administration (NTIA), to account for propagation, diffraction, and troposcatter losses that the radar pulses undergo before they reach the LTE system. As a performance metric, we evaluate the throughput of the LTE system in the uplink direction for various distances between the radar and the cellular system. Our simulation results indicate an LTE link will remain operational even in severe interference conditions. In fact, the LTE system as close as 100 km away from the radar undergoes less than 10% throughput loss from the LTE total throughput, and the throughput loss is less than 30% when the radar is only 50 km away from the LTE.

UsICIC—A Proactive Small Cell Interference Mitigation Strategy for Improving Spectral Efficiency of LTE Networks in the Unlicensed Spectrum

The deployment of long term evolution (LTE) in the unlicensed spectrum (LTE-U) has been gaining significant industry momentum in recent months. The US 5-GHz Unlicensed National Information Infrastructure (UNII) bands that are currently under consideration for LTE deployment in the unlicensed spectrum contain only a limited number of 20 MHZ channels. Thus, in a dense multi-operator deployment scenario, one or more LTE-U small cells have to coexist and share the same 20 MHz unlicensed channel with each other and with the incumbent Wi-Fi. In this paper, we present the scenario and demonstrate that in the absence of an explicit interference mitigation mechanism, there will be a significant degradation in the overall LTE-U system performance for LTE-U cochannel coexistence in countries that do not mandate listen-before-talk (LBT) requirements. We then present the unlicensed spectrum intercell interference co-ordination (usICIC) mechanism as a time-domain multiplexing technique for interference mitigation for the sharing of an unlicensed channel by multioperator LTE-U small cells. Through extensive simulation results, we also demonstrate that our proposed usICIC mechanism will result in 40% or more improvement in overall LTE-U system performance.

Effect on System Performance due to Upgradation of 2G/3G System to LTE

In the current environment of burgeoning demand for mobile broadband, Long Term Evolution (LTE) is the most preferred wireless technology for the mobile operators. Considering the legacy multi-technology networks, operators need to strategically work upon maximizing their revenue while minimizing their cost and satisfying the subscriber’s requirements as well. Operators have a choice between 2 network strategies- LTE overlay and single radio access network (SRAN). A survey carried out proved SRAN to be the optimum LTE deployment strategy considering the total cost of ownership (TCO). This paper discusses the effect on the system performance due to the up gradation of network from second generation (2G) to third generation (3G) to long term evolution (LTE) systems using Nokia Siemens Network Flexi multi-radio base stations. Measurements of RSRP (Reference Signal Received Power), SINR (Signal to Interference plus Noise Ratio) and throughput were carried out by a drive test within 2Km of the deployed site area which indicated that all the 3 parameters were affected as the user equipment moved away from the site area and towards the cell edges. This problem can be addressed by deployment of low power relay nodes, one of the promising techniques, for increasing the coverage of LTE advanced networks (the future of LTE systems).

Throughput and Fairness Analysis of Wi-Fi and LTE-U in Unlicensed Band

Shortage of available licensed spectrum is a major barrier to the development of 5G networks. The deployment of long term evolution (LTE) in unlicensed spectrum (LTE-U) is a promising solution to overcome such a barrier. However, the interaction between LTE-U and Wi-Fi in unlicensed spectrum has not been well understood. In this paper, we use stochastic geometry to develop a framework for a multi-radio access technologies (multi-RAT) heterogeneous network, which consists of an LTE-U tier and a Wi-Fi tier. To reduce the intra- and inter-RAT interference, LTE-U employs an ALOHA-like random access scheme and Wi-Fi performs carrier sensing and energy detection before transmission. We derive the coverage probability and spatial throughput of Wi-Fi and LTE-U networks, and perform the asymptotic analysis when the density of Wi-Fi and LTE-U nodes approach infinity. Based on our analysis, we investigate the effect of network parameters on the coverage probability and spatial throughput of these networks. Furthermore, in order to achieve weighted max-min fairness, we optimize the retention probability of LTE-U nodes to maximize the minimum weighted spatial throughput of Wi-Fi and LTE-U networks.

Overview of LTE Spectrum Sharing Technologies

Long-Term Evolution (LTE) communication systems feature advanced frequency reuse and interference coordination techniques providing faster and more secured mobile services. However, the network capacity in licensed spectrum is still behind market demands. Dynamic spectrum access or spectrum sharing in other frequently vacant or unlicensed frequency bands is considered an effective means to boost system throughput. Different from operations in licensed spectrum with exclusive access, LTE deployment needs to take into account the distinct regulations on channel access to each shared frequency band, in order to avoid interference to incumbent users, and to maintain fair play with peer operators in heterogeneous networks. This paper presents an overview on LTE spectrum sharing technologies on three popular spectrums, including the TV white-space channels, the frequently unused service-dedicated 3.5-GHz citizens broadband radio service spectrums, and the 5-GHz unlicensed bands. Existing spectrum usage in these frequency bands is analyzed, and the proposed methodologies on compliant operations are discussed for the reference of potential solutions to more efficient spectrum sharing mechanisms in the next generation mobile networks.

Isolation between three antennas at 700 MHz: for handheld terminals

To address the antenna design challenges posed by many frequency bands, introduced with long-term evolution deployment, this study proposes the use of separate transmit (Tx) and receive (Rx) narrow-band antennas. In addition, a diversity Rx (Dx) antenna is needed for multiple-input multiple-output performance. Although the isolation between two antennas at low frequencies (700 MHz) is crucial for the successful implementation of 4G in handheld terminals, it becomes more challenging when considering isolation among three antennas (one Tx and two Rx antennas) at low frequencies. Hence, a method that improves the isolation between the ports of one Tx and two Rx antennas is presented here.

Evaluation of Long Term Evolution Cellular Network Performance when Transmitting Multi-view Video Content

The Long Term Evolution (LTE) cellular technology provides higher data rates than its predecessor technologies. This advancement paves the way for more data services, including improved multimedia services. Three-dimensional (3D) video transmission is one such service that can benefit from LTE deployment. For a positive uptake of 3D video transmission, the network must provide a good Quality of Service (QoS). In this paper the authors evaluate the LTE network's performance when transmitting Multi-view Video Coding (MVC) using simulcast and inter-view prediction coding. Furthermore, the authors evaluate the system using both the H.264/AVC (Advanced Video Coding) and the more recent High Efficiency Video Coding (HEVC) and their MVC extensions. Results show that, in an urban environment, LTE can accommodate a maximum of 93 users per cell, with adequate QoS, when transmitting 3D HEVC video at Common Intermediate Format (CIF) resolution. Moreover, cross-layer techniques can be used to reduce the QoS degradation as the user moves away from the eNodeB by transmitting lower resolution video.