Modified Iterative Sphere Decoding Algorithm in LTE System

2013 ◽  
Vol 765-767 ◽  
pp. 611-614
Author(s):  
Qin Zhu ◽  
Xiao Wen Li
Keyword(s):  
Channel Equalization ◽  
Detection Algorithm ◽  
Qr Decomposition ◽  
Sphere Decoding ◽  
Decoding Algorithm ◽  
Algorithm Performance ◽  
Awgn Channel ◽  
Term Evolution ◽  
Simulation Results

In the long-term evolution (LTE) system, channel equalization makes compensation to restore the original signal, the paper puts forward iteration sphere decoding algorithm which combines traditional sphere decoding and the improved QR based on the conventional QR decomposition detection algorithm. It can effectively reduce the system complexity. At the same time, in QPSK and 16QAM, the simulation results show that the improved QR iterative sphere decoding algorithm performance is better with higher SNR in AWGN channel.

Study of FCLSD Algorithm Performance Based on LTE System

2012 ◽  
Vol 195-196 ◽  
pp. 96-103
Author(s):  
Ke Wen Liu ◽  
Quan Liu
Keyword(s):  
High Performance ◽  
Hardware Implementation ◽  
Low Complexity ◽  
Detection Algorithm ◽  
Sphere Decoding ◽  
Mimo Detection ◽  
Decoding Algorithm ◽  
Algorithm Performance ◽  
Simulation Results ◽  
Ber Performance

Soft-output complex list sphere decoding algorithm is a low-complexity MIMO detection algorithm and its BER performance approximates that of Maximum-Likelihood. However, it has a problem of not fixed complexity, and which make it very difficult to implement. To resolve this and try best to retain the advantages of the algorithm, a modified algorithmfixed complex list sphere decoding algorithm was proposed. Based on LTE TDD system, this paper studies the performance of the FCLSD algorithm. The simulation results show that: the BER performance of the FCLSD algorithm is close to that of the CLSD algorithm. However, when the number of antennas and modulation order increasing, the FCLSD algorithm is non-constrained of spherical radius and has fixed complexity. In addition, hardware implementation of the FCLSD algorithm could be carried out by parallel processing, thereby greatly reducing the algorithm complexity. So it is a high-performance algorithm of great potential.

scholarly journals 3G Long Term Evolution Baseband Processing with Application-Specific Processors

2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
Perttu Salmela ◽  
Juho Antikainen ◽  
Teemu Pitkänen ◽  
Olli Silvén ◽  
Jarmo Takala
Keyword(s):  
Software Defined Radio ◽  
High Capacity ◽  
Long Term Evolution ◽  
Sphere Decoding ◽  
Interprocessor Communication ◽  
Term Evolution ◽  
Data Rates ◽  
Universal Mobile Telecommunications System ◽  
Application Specific

Data rates in the upcoming 3G long term evolution (LTE) standard will be manifold when compared to the current universal mobile telecommunications system. Implementing receivers conforming with the high-capacity transmission techniques is challenging due to the complexity and computational requirements of algorithms. In this study, the software defined radio (SDR) is targeted and the four essential baseband functions of the 3G LTE receiver, namely, list sphere decoding, fast Fourier transform, QR decomposition, and turbo decoding, are addressed and the functions are implemented as application specific processors (ASPs). As a result, the design space that describes the essential computational challenges of 3G LTE receivers is clarified and estimates of area, power, and interprocessor communication buffer requirements are presented.

scholarly journals An Adaptive Measurement Report Period and Handoff Threshold Scheme Based on SINR Variation in LTE-A Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jenhui Chen ◽  
Ching-Yang Sheng
Keyword(s):  
Decision Making ◽  
Reference Signal ◽  
Critical Parameters ◽  
Threshold Scheme ◽  
Term Evolution ◽  
Ping Pong ◽  
Adaptive Measurement ◽  
Simulation Results ◽  
Unnecessary Handoff

This paper deals with the problem of triggering handoff procedure at an appropriate point of time to reduce the ping-pong effect problem in the long-term evolution advanced (LTE-A) network. In the meantime, we also have studied a dynamic handoff threshold scheme, named adaptive measurement report period and handoff threshold (AMPHT), based on the user equipment’s (UE’s) reference signal received quality (RSRQ) variation and the moving velocity of UE. AMPHT reduces the probability of unnecessarily premature handoff decision making and also avoids the problem of handoff failure due to too late handoff decision making when the moving velocity of UE is high. AMPHT is achieved by two critical parameters: (1) a dynamic RSRQ threshold for handoff making; (2) a dynamic interval of time for the UE’s RSRQ reporting. The performance of AMPHT is validated by comparing numerical experiments (MATLAB tool) with simulation results (the ns-3 LENA module). Our experiments show that AMPHT reduces the premature handoff probability by 34% at most in a low moving velocity and reduces the handoff failure probability by 25% in a high moving velocity. Additionally, AMPHT can reduce a large number of unnecessary handoff overheads and can be easily implemented because it uses the original control messages of 3GPP E-UTRA.

An Improved Construction for Yielding Nonbinary LDPC Codes

2014 ◽  
Vol 556-562 ◽  
pp. 6307-6310
Author(s):  
Li Sheng Zhang ◽  
Zhi Peng Huang ◽  
Fan Xin Zeng
Keyword(s):  
Belief Propagation ◽  
Ldpc Codes ◽  
Construction Method ◽  
Decoding Algorithm ◽  
Construction Methods ◽  
Awgn Channel ◽  
Simulation Results ◽  
Nonbinary Ldpc Codes

In this paper, we investigate construction methods for producing nonbinary LDPC codes, and a family of nonbinary LDPC codes over is presented and its properties are derived. Compared to the second method presented by Ref. [5], simulation results show that the proposed LDPC codes perform well over the AWGN channel under belief propagation decoding algorithm and have an almost same BER curve as the ones in Ref. [5]. However, the resultant construction method is simpler than the latter’s.

scholarly journals Co-Channel Interference Suppression for LTE Passive Radar Based on Spatial Feature Cognition

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 117
Author(s):  
Haitao Wang ◽  
Xiaoyong Lyu ◽  
Kefei Liao
Keyword(s):  
Interference Suppression ◽  
Reference Signal ◽  
Spatial Spectrum ◽  
Base Station ◽  
Base Stations ◽  
Passive Radar ◽  
Term Evolution ◽  
Reference Signals ◽  
Simulation Results

Passive radars based on long-term evolution (LTE) signals suffer from sever interferences. The interferences are not only from the base station used as the illuminator of opportunity (BS-IoO), but also from the other co-channel base stations (CCBS) working at the same frequency with the BS-IoO. Because the reference signals of the co-channel interferences are difficult to obtain, cancellation performance degrades seriously when traditional interference suppression methods are applied in LTE-based passive radar. This paper proposes a cascaded cancellation method based on the spatial spectrum cognition of interference. It consists of several cancellation loops. In each loop, the spatial spectrum of strong interferences is first recognized by using the cyclostationary characteristic of LTE signal and the compressed sensing technique. A clean reference signal of each interference is then reconstructed according to the spatial spectrum previously obtained. With the reference signal, the interferences are cancelled. At the end of each loop, the energy of the interference residual is estimated. If the interference residual is still strong, then the cancellation loop continues; otherwise it terminates. The proposed method can get good cancellation performance with a small-sized antenna array. Theoretical and simulation results demonstrate the effectiveness of the proposed method.

Research on Uplink Channel Estimation Method in TD-LTE System

2011 ◽  
Vol 135-136 ◽  
pp. 847-851
Author(s):  
Cui Zhen Sun ◽  
Zhao Hua Zeng
Keyword(s):  
Channel Estimation ◽  
Estimation Method ◽  
Data Rate ◽  
Pilot Signal ◽  
High Data ◽  
System A ◽  
Term Evolution ◽  
Simulation Results ◽  
Evolution Scheme

LTE is a long term evolution scheme of 3GPP, as a using extensively communication standards, it has higher data rate and higher quality. Channel estimation plays a quite important role in the LTE system which requires the high data rate and quality. In the article, based on the analysis of the LS and MMSE algorithms of the LTE system, a advised algorithm is adopted. The pilot signal is processed before the channel estimation by reducing noise in time domain. The simulation results demonstrate that the advised algorithm is a preferable choice in estimation performance, simultaneously; the advised has obviously reduced the algorithm complexity.

scholarly journals Fuzzy Logic Based Coverage and Cost Effective Placement of Serving Nodes for 4G and Beyond Cellular Networks

2017 ◽  
Vol 2017 ◽  
pp. 1-25 ◽  
Author(s):  
Arthi Murugadass ◽  
Arulmozhivarman Pachiyappan
Keyword(s):  
Site Selection ◽  
Unit Area ◽  
Cost Effective ◽  
Base Stations ◽  
Term Evolution ◽  
Transmission Quality ◽  
Simulation Results ◽  
Coverage Holes

The densification of serving nodes is one of the potential solutions to maximize the spectral efficiency per unit area. This is preposterous on account of conventional base stations (BS) for which site procurement is costly. Long term evolution-advanced (LTE-A) defines the idea of heterogeneous networks (HetNets), where BSs with different coverage and capacity are utilized to guarantee the quality of service (QoS) requirements of the clients. To maximize the transmission quality of the clients in the coverage holes, LTE-A also defines multihop relay (MHR) networks, where the relay stations (RSs) are also placed along with the BSs. Unfortunately, the placement approaches for HetNet and MHR serving nodes are not standardized. In this work, two different approaches like site selection with maximum service coverage (SSMSC) and site selection with minimum placement cost (SSMPC) are proposed, which identifies the required number of serving nodes, their types, and the placement locations to maximize the coverage and to maintain the placement cost (PC) within the limits of the total placement budget. The simulation results demonstrate that the proposed approaches are computationally less complex and offer enhanced performance in terms of aggregate PC, coverage, and power proportion compared to the other conventional approaches.

scholarly journals A Countermeasure against Smart Jamming Attacks on LTE Synchronization Signals

2020 ◽  
pp. 626-632
Author(s):  
Mert Eygi ◽  
◽  
Gunes Karabulut Kurt
Keyword(s):  
Wireless Communication ◽  
Communication Technology ◽  
Energy Efficient ◽  
Specific Region ◽  
Jamming Attacks ◽  
Jamming Attack ◽  
Term Evolution ◽  
Physical Channel ◽  
Simulation Results

Long-Term Evolution (LTE) is one of the most frequently used wireless communication technology. As every wireless network, LTE is vulnerable to physical layer (PHY) jamming attacks due to the broadcast nature of channels. Since the jammer attacks are getting smarter and energy efficient, they can target a specific region or physical channel instead of entire band. Targeting the physical LTE downlink Synchronization Signals (SS) could be the most dangerous objective. In this paper, we investigate LTE PHY jamming attack against only primary and secondary synchronization signals. Jammer detection is performed by using Neyman-Pearson theorem. Then, a countermeasure method is proposed. Simulation results show that the proposed countermeasure can achieve lower pollution and better correct cell id performances during smart jamming attack against SS.

scholarly journals Enhanced ABSF Algorithm with a Relay Function in LTE Heterogeneous Networks

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1343
Author(s):  
Lehung Nguyen ◽  
Sungoh Kwon
Keyword(s):  
User Satisfaction ◽  
Base Stations ◽  
System Throughput ◽  
Intercell Interference ◽  
Scheduling Policy ◽  
The Third ◽  
Term Evolution ◽  
Simulation Results ◽  
Almost Blank Subframe

In this study, we enhance the almost blank subframe (ABSF) algorithm in a Long Term Evolution (LTE) heterogeneous network (HetNet) by providing a relay function. The ABSF is a technique proposed by the Third Generation Partnership Project to reduce interference in a HetNet. Despite the fact that the ABSF effectively mitigates intercell interference, it has two major disadvantages. First, the ABSF algorithm alters the scheduling policy of macro base stations. Second, it degrades the capacity of users served by femto base stations. Our proposed enhanced algorithm applies a relay function to assist victim macro user equipment (VMUE), and it reduces the side effects caused by the ABSF algorithm. Taking resource allocation and power control into account, the relay function assists VMUE in such a way that interference with other users is minimized. Via simulation results, the proposed algorithm exhibits improvements of 18% and 8% for system throughput and user satisfaction, respectively, in comparison with the conventional ABSF.

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