Performance Of Long Term Evolution System Research Articles

LTE Modulation and Coding Schemes for 6G Networks

Background: Long Term Evolution (LTE) is the fourth generation (4G) mobile communication technology developed by the 3rd Generation Partnership Project (3GPP). In comparison to previous generations of cellular systems, LTE incorporates several innovative technologies. These innovative technologies are used to increase spectrum efficiency and data speeds, as envisioned by designers Methods: This study provides a comprehensive investigation of orthogonal frequency division multiple access and Single carrier frequency division multiple access transmission model and investigate physical layer performance of LTE system using MATLAB – Simulink Environment. Results: By providing spectrum flexibility, the SC-FDMA-OFDMA 16 QAM with AWGN Channel Transmission model achieves a higher outcome and has a packet loss rate of 0%. The numerical evaluation is used to illustrate the trade-off between loss of capacity in the time and frequency domains. Conclusion: SC-FDMA has a lower multipath propagation rate and peak to average power ratio than OFDM; therefore, multipath must be eliminated to make it more efficient. The final section of this study contains a full description of the techniques required in simulating a simple communication model.

Indoor propagation models for emulated LTE networks

The growth in mobile network data traffic is even more noticeable in networks compatible with the Long-Term Evolution (LTE) standard. As such, both academia and industry seek mechanisms aimed at improving new communications systems, therefore, new test benches are required. The emulators are candidates to validate the proposals without affecting the real central systems. However, many papers that seek to address LTE emulation ignore the not-so-insignificant effect of wireless media propagation features. In this work, a characterization of the main propagation models used by typical emulation systems has been carried out. The network simulator three tool using indoor propagation models, has compared the outcomes achieved compared with the results obtained in a real test bench. Since most mobile data in the coming years is forecast to be mobile video traffic, this study focuses on a live video streaming service, considering both real-time message protocol and real-time streaming protocol transmission protocols. From the results, we demonstrate that only one of the propagation models under study is able to equate with a real LTE system performance. Thereby, the emulation system under this specific setup is well suited to conducting performance tests of LTE networks supporting video streaming services in indoor scenarios.

RS Codes for Downlink LTE System over LTE-MIMO Channel

Nowdays, different applications require a modern generation of mobile communication systems; long term evolution (LTE) is a candidate to achieve this purpose. One important challenge in wireless communications, including LTE systems, is the suitable techniques of controlling errors that degrade system performance in transmission systems over multipath fading channels. Different forward Error correction (FEC) techniqes are required to improve the robustness of transmission channels. In this paper, Reed-Solomon (RS) codes were used with a downlink LTE system over a LTE-MIMO channel. This research contributes by combining RS codes that have low decoding complexity (by using hard decision decoding) with a LTE-MIMO channel to improve downlink LTE system performance. The results show that using RS codes clearly improves LTE system performance and thus decreases Bit Error Rates (BER) more than convolutional and turbo codes which have high decoding complexity. Lastly, the results show also extra improvements of downlink LTE system performance by increasing the number of antennas of the LTE-MIMO channel.

Downlink LTE System Performance Improvement by Using BCH Codes over LTE-MIMO Channel

Long-term Evolution (LTE) has potential feasibility to implement high-speed data transmission. This technology is essential for accommodating the rising utilization of data and voice service. Nonetheless, the main problem is the deteriorated performance of wireless communication systems following the elevation in bit error rate (BER) owing to multipath fading environments. Therefore, using channel coding is essential to reduce BER, which leads to enhancement of system performance of digital communication systems. Previous studies have reported utilization of channel codes including turbo and convolutional codes in LTE systems for attaining error control system. As such, the key challenge of selecting category of coding method is the trade-off between elevating decoding complexity and enhancing system performance. Hence, the study herein proposed Bose and Chaudhuri (BCH) codes as channel coding for downlink LTE system over MIMO channel. This is aimed to attain an adaptive error control with low complexity compared to turbo and convolutional codes. The findings indicated that BCH codes had reduced BER compared to turbo and convolutional codes in both quadrature phase-shift keying (QPSK) modulation schemes and binary phase-shift keying (BPSK) with regard to the downlink LTE system performance. The suggested method had approximately 4dB coding gain at 1X10-1 against both of convolutional and turbo codes in BPSK. While, for QPSK, the proposed method had approximately 5dB and 6dB compared to turbo and convolutional codes, respectively. Nonetheless, enhanced performance of the suggested system was observed through reducing BER of the received data by adding the number of antennas in MIMO channel.

Optimisation of LTE system with open- and closed-loop spatial multiplexing transmission modes

ABSTRACTIn this paper, an optimised Long-Term Evolution (LTE) system model using advanced modulation schemes and equalisation techniques is presented. This new approach of optimising the LTE system performance enables us to achieve a Bit Error Rate (BER) of 10−3 and in some cases it goes to an optimum value of 10−4. This achievement is quite unique as compared to the work that has been reported in the past. The crux about the whole work is that all the results have been obtained within the same bandwidth range, i.e. 10 MHz and hence provides a very cost-effective solution for the real-time applications where increased bandwidth requirement is a big constraint.

A New Downlink Scheduling Algorithm Proposed for Real Time Traffic in LTE System

Abstract The Third Generation Partnership Project (3GPP) has developed a new cellular standard based packet switching allowing high data rate, 100 Mbps in Downlink and 50 Mbps in Uplink, and having the flexibility to be used in different bandwidths ranging from 1.4 MHz up to 20 MHz, this standard is termed LTE (Long Term Evolution). Radio Resource Management (RRM) procedure is one of the key design roles for improving LTE system performance, Packet scheduling is one of the RRM mechanisms and it is responsible for radio resources allocation, However, Scheduling algorithms are not defined in 3GPP specifications. Therefore, it gets a track interests for researchers. In this paper we proposed a new LTE scheduling algorithm and we compared its performances with other well known algorithms such as Proportional Fairness (PF), Modified Largest Weighted Delay First (MLWDF), and Exponential Proportional Fairness (EXPPF) in downlink direction. The simulation results shows that the proposed scheduler satisfies the quality of service (QoS) requirements of the real-time traffic in terms of packet loss ratio (PLR), average throughput and packet delay. This paper also discusses the key issues of scheduling algorithms to be considered in future traffic requirements.

System level simulation platform for Cognitive LTE

The third Generation Partnership Project (3GPP) Long-Term Evolution (LTE) is becoming the first truly global wireless communication standard. LTE system is expected to have an ability to sense the wireless environment. To evaluate the performance of cognitive LTE network, the design of system level simulation platform is proposed. This platform realizes relevant spectrum sensing algorithm and dynamic spectrum allocation strategy. The architecture of this simulation platform is introduced. Based on LTE system level simulator, cognitive radio function is implemented and five modules are developed, including spectrum sensing module, spectrum allocation module, spectrum switching module, link adaptation module, link---system interface module. Class diagram of the simulation platform is also given in this paper. Simulation flow chart introduces the working mechanism in detail. Finally network performance of cognitive LTE system, including average throughput, average spectral efficiency, detection probability, false alarm probability, miss alarm probability, is evaluated using this platform.

Performance Evaluation of Different Coding and Modulation Scheme in LTE Using Different Bandwidth and Correlation Levels

Performance of present-generation wireless communication, long term evolution (LTE) is greatly affected by bit error rate (BER). So, objective of this paper is to present a quantitative performance comparison of different modulation techniques based on parameters, BER at different level of signal to noise ratio (SNR) and utilized bandwidth by using different level of correlation in multiple input multiple output (MIMO). The comparative analysis has been done by considering LTE support bandwidths of 1.4, 3, 5, 10, 15 and 20 MHz. This LTE based simulation work for urban areas in a fast moving environment is performed on the basis of different antenna arrays like 2 × 2 and 4 × 4. Comparative evaluation in form of graphical results shows that BER is relatively very low at low level correlation of MIMO and LTE system performance based on the parameter BER is better at 10 MHz bandwidth.

Interference Management in Lte Downlink Networks

Two major challenges for evolving LTE (Long Term Evolution) networks are to achieve enhanced system capacity and cell coverage compared with WCDMA (Wideband Code Division Multiple Access) system. Effective utilization of radio resources as well as dense spectrum reuse are at the core to attain these targets. However, dense frequency reuse may increase inter-cell interference, which in turn severely limits the capacity of users in the system. Inter-cell interference can restrict overall system performance in terms of throughput and spectral efficiency, especially for the users located at the cell edge area. Hence, careful management of inter-cell interferences becomes crucial to improve LTE system performance. In this paper, interference mitigation schemes for LTE downlink networks are investigated.

An Adaptive Threshold Feedback Compression Scheme Based on Channel Quality Indicator (CQI) in Long Term Evolution (LTE) System

Channel quality indicator (CQI) feedback in long-term evolution (LTE) system is an essential technique in describing the instantaneous channel state information. The CQI calculations highly depend on the accuracy of the channel estimation process in order to assign appropriate modulation and coding scheme. However, one of the critical issues affecting the LTE system performance is obtaining the CQI for each transmission period which will inevitably cost many resources. Therefore, an appropriate method for reducing CQI feedback overhead along with accurate channel estimation technique is required to manage the allocated resources and obtains significant improvements in system performance. In this paper, an adaptive threshold feedback compression scheme based on CQI scheme is proposed to obtain better system performance in terms of system throughput and error rate in LTE system. This proposed adaptive scheme dynamically adapts its threshold level to the signal to noise ratio variations, thus increasing the throughput and reducing the CQI feedback overhead. Results show that the proposed CQI based adaptive threshold feedback compression scheme enhances the tradeoff between system throughput and block error rate.

An Optimal Standard-Compliant MIMO Scheduler for LTE Downlink

Frequency domain packet scheduling (FDPS) problem is one of the crucial elements in the 3rd generation partnership project (3GPP) long term evolution (LTE) system, which has a tremendous impact on the LTE system performance. However, optimal resource allocation through FDPS is a complicated and challenging task when multiple input and multiple output (MIMO)-orthogonal frequency division multiple access (OFDMA) technology is adopted. In this paper, we propose a new FDPS scheme for the 3GPP LTE downlink channels that optimally assigns time-frequency resources to users based on the proportional fairness metric. The proposed scheme jointly considers multiple system constraints imposed by the 3GPP LTE standard that arise in the MIMO mode selection and modulation and coding scheme (MCS) selection. Such scheduling problem is considered to be among the most difficult optimization problems. Our major contribution in this paper is that we model the FDPS problem as a unique binary linear programming problem and prove that the problem is totally unimodular. With the total unimodularity property, we are able to solve the complicated FDPS problem using efficient linear programming problem solvers. Simulation results show that our proposed scheme outperforms the existing state-of-the-art MIMO proportional fair scheduling algorithms used in the FDPS problem.

Effect of Bandwidth Scalability on System Performance in the Downlink LTE Systems

Long Term Evolution (LTE) system employs Orthogonal Frequency Division Multiple Access (OFDMA) in downlink in order to support network deployment using various system bandwidth configurations i.e., 1.4MHz, 3MHZ, 5MHz, 10MHz, 15MHz and 20MHz. The bandwidth scalability enables operator to access multiple channels to achieve higher peak data rates. Also, the bandwidth scalability allows operators to deploy LTE network with the existing spectrum or newly licensed band. Therefore the study on performance of LTE system with different bandwidth configuration becomes vital. Hence in this paper, an attempt has been made to study and compare the performance of LTE system with different spectrum configuration i.e., 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz for Constant Bit Rate (CBR) traffic scenario in the downlink. The performance metrics considered for simulation studies are aggregate bytes received, average throughput, average delay and average jitter. Keywords- LTE, OFDMA, downlink, bandwidth scalability, aggregate bytes received, avearge throughput, avearge delay, average jitter

Looking at LTE in Practice: A Performance Analysis of the LTE System Based on Field Test Results

This article introduces a practical performance analysis of the long-term evolution (LTE) cellular system based on field test results from a commercially deployed Third-Generation Partnership Project's (3GPP?s) Release 8 LTE network in Band-3 (i.e., 1,800 MHz, sometimes termed LTE1,800 MHz) with 20-MHz channel bandwidth. The presented analysis demonstrates the downlink (DL) and uplink (UL) throughputs in mobility conditions in addition to other aspects of the LTE system such as link budget, cell coverage, spectral efficiency, and handover performance. LTE's key features such as multiple-input, multiple-output (MIMO) and higher-order modulation [i.e., 64 quadrature amplitude modulation (QAM)] are assessed in different radio frequency (RF) conditions. A comparison is presented between LTE and 3GPP Release 8 evolution of high-speed packet access (HSPA+) with a dual-cell high-speed DL packet access (DC-HSDPA) feature based on the universal mobile telecommunications system (UMTS) 2,100-MHz commercial network with 10-MHz bandwidth (i.e., 2x5-MHz adjacent carriers). The presented LTE network performance analysis and the comparison with the HSPA+ network can be used to benchmark the LTE system performance and evaluate the gains and merits of deploying the LTE network. It has been demonstrated that the LTE system outperforms the HSPA+ system in terms of spectrum efficiency, 64-QAM utilization, cell coverage, and handover delay. The LTE system offers a 34% improvement in spectrum efficiency, 40% 64-QAM utilization versus 7.4% for the HSPA+ system, and a 60% reduction in data interruption time during handover.

Simulating LTE Cellular Systems: An Open-Source Framework

Long-term evolution (LTE) represents an emerging and promising technology for providing broadband ubiquitous Internet access. For this reason, several research groups are trying to optimize its performance. Unfortunately, at present, to the best of our knowledge, no open-source simulation platforms, which the scientific community can use to evaluate the performance of the entire LTE system, are freely available. The lack of a common reference simulator does not help the work of researchers and poses limitations on the comparison of results claimed by different research groups. To bridge this gap, herein, the open-source framework LTE-Sim is presented to provide a complete performance verification of LTE networks. LTE-Sim has been conceived to simulate uplink and downlink scheduling strategies in multicell/multiuser environments, taking into account user mobility, radio resource optimization, frequency reuse techniques, the adaptive modulation and coding module, and other aspects that are very relevant to the industrial and scientific communities. The effectiveness of the proposed simulator has been tested and verified considering 1) the software scalability test, which analyzes both memory and simulation time requirements; and 2) the performance evaluation of a realistic LTE network providing a comparison among well-known scheduling strategies.