scholarly journals Coherent Detection of Non-Orthogonal Spectrally Efficient Multicarrier Signals Using a Decision Feedback Algorithm

2021 ◽  
Vol 24 (5) ◽  
pp. 22-35
Author(s):  
S. B. Makarov ◽  
S. V. Zavjalov ◽  
D. C. Nguyen ◽  
A. S. Ovsyannikova
Keyword(s):  
Mobile Communications ◽  
Mutual Influence ◽  
Detection Algorithm ◽  
Coherent Detection ◽  
Decision Feedback ◽  
Interchannel Interference ◽  
Spectrally Efficient ◽  
Energy Gains ◽  
Feedback Algorithm ◽  
Error Probabilities

Introduction. Spectrally efficient frequency division multiplexing (SEFDM) is a promising technology for improving spectral efficiency. Since SEFDM signals transmitted on subcarriers are not orthogonal, interchannel interference occurs due to the mutual influence of signals transmitted on adjacent subcarriers. Algorithms for receiving SEFDM signals can be distinguished into element-by-element coherent detection and maximum-likelihood sequence estimation (MLSE). The former method, although being simpler, is characterized by a low bit error rate performance. The latter method, although providing for a higher energy efficiency, is more complicated and does not allow high absolute message rates.Aim. To consider a trade-off solution to the problem of coherent detection of SEFDM signals under the condition of significant interchannel interference, namely, the use of an iterative algorithm of element-by-element processing with decision feedback at each subcarrier frequency.Materials and methods. Analytical expressions for the operation of a demodulator solver were derived. A simulation model for transmission of SEFDM signals was built in the MatLab environment, including element-by-element detection with decision feedback.Results. The simulation results confirmed the efficiency of the proposed algorithm. For error probabilities p =102…103, the energy gains reach values from 0.2 to 7.5 dB for different values of the non-orthogonal subcarrier spacing. At the same time, the efficiency of the detection algorithm with decision feedback turns out to be significantly lower than that when using the detection algorithm MLSE.Conclusion. The proposed detection algorithm can be used in future generations of mobile communications, which require high transmission rates. By reducing the computational complexity of the algorithm, it is possible to provide for a lower power consumption of mobile devices.

scholarly journals Analytical Performance Evaluation of Massive MIMO Techniques for SC-FDE Modulations

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 533
Author(s):  
Daniel Fernandes ◽  
Francisco Cercas ◽  
Rui Dinis
Keyword(s):  
Mobile Communications ◽  
Massive Mimo ◽  
Matched Filter ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Correlation Factor ◽  
Decision Feedback ◽  
Future Generations ◽  
Ongoing Research ◽  
Single Carrier

In the Fifth Generation of telecommunications networks (5G), it is possible to use massive Multiple Input Multiple Output (MIMO) systems, which require efficient receivers capable of reaching good performance values. MIMO systems can also be extended to massive MIMO (mMIMO) systems, while maintaining their, sometimes exceptional, performance. However, we must be aware that this implies an increase in the receiver complexity. Therefore, the use of mMIMO in 5G and future generations of mobile receivers will only be feasible if they use very efficient algorithms, so as to maintain their excellent performance, while coping with increasing and critical user demands. Having this in mind, this paper presents and compares three types of receivers used in MIMO systems, for further use with mMIMO systems, which use Single-Carrier with Frequency-Domain Equalization (SC-FDE), Iterative Block Decision Feedback Equalization (IB-DFE) and Maximum Ratio Combining (MRC) techniques. This paper presents and compares the theoretical and simulated performance values for these receivers in terms of their Bit Error Rate (BER) and correlation factor. While one of the receivers studied in this paper achieves a BER performance nearly matching the Matched Filter Bound (MFB), the other receivers (IB-DFE and MRC) are more than 1 dB away from MFB. The results obtained in this paper can help the development of ongoing research involving hybrid analog/digital receivers for 5G and future generations of mobile communications.

Accelerometer Sensor Based Fall Sensing for Elderly

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Anas Mohd Noor ◽  
Hafizudin Zainudin ◽  
Normaheran Hanafi ◽  
Siti Aishah Baharuddin ◽  
Mohamad Aliff Abdul Rahim
Keyword(s):  
Mobile Communications ◽  
Signal Transmission ◽  
Cost Effective ◽  
Fall Detection ◽  
Detection Algorithm ◽  
Prototype System ◽  
Accelerometer Sensor ◽  
Wireless Signal ◽  
Overall Performance ◽  
Key Parameter

Fall can be recognized as an abnormal or action of losing an upright motion which will cause people especially elderly to suffer from pain and more seriously can affect one’s health. Being able to detect fall is key parameter to decrease the risk of severe injury to the seniors. There are such existing fall detection products on the market to assist elderly so that immediate response could be taken. However, due to complexity system, high cost and employing outside technology, these products initiate limitations such as maintenance and system enhancement. In this project, a fall detection device and system is developed using local technology, simple and cost effective. The prototype system consist of accelerometer sensing circuit, microcontroller with wireless signal transmission, Global System for Mobile Communications (GSM) notification alert for mobile phone and graphical user interface (GUI) to obtain real-time monitoring. The simple fall detection algorithm is developed to ensure false detection could be minimized. The overall performance of the developed device and system is proven reliable and practical. 

An H.264/AVC Error Detection Algorithm Based on Syntax Analysis

2011 ◽  
pp. 215-234
Author(s):  
Luca Superiori ◽  
Olivia Nemethova ◽  
Markus Rupp
Keyword(s):  
Performance Evaluation ◽  
Error Detection ◽  
Detection Algorithm ◽  
Video Sequences ◽  
Video Streams ◽  
Syntax Analysis ◽  
Standard Methods ◽  
Free Data ◽  
Error Probabilities ◽  
Low Rate

In this chapter, we present the possibility of detecting errors in H.264/AVC encoded video streams. Standard methods usually discard the damaged received packet. Since they can still contain valid information, the localization of the corrupted information elements prevents discarding of the error-free data. The proposed error detection method exploits the set of entropy coded words as well as range and significance of the H.264/AVC information elements. The performance evaluation of the presented technique is performed for various bit error probabilities. The results are compared to the typical packet discard approach. Particular focus is given on low-rate video sequences.

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