scholarly journals Dynamic Spatial Diversity Combiner pada Kanal Fading

2019 ◽  
Vol 7 (3) ◽  
pp. 466
Author(s):  
DWI ARYANTA ◽  
RIENZY PRATAMA LONDONG ALLO
Keyword(s):  
Spatial Diversity ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Signal Quality ◽  
Diversity Combining ◽  
Matlab Simulation ◽  
Equal Gain Combining ◽  
Performance Simulation ◽  
Improved Performance ◽  
Bpsk Modulation

ABSTRAKKanal transmisi radio berkontribusi pada terjadinya efek fading yang dapat berpengaruh pada terjadinya penurunan kualitas sinyal pada penerima. Salah satu solusi yang digunakan untuk menekan efek fading adalah penggunaan Spatial Diversity di sisi penerima. Pada penelitian ini digunakan suatu teknik Dynamic Spatial Diversity Combining yang memadukan Selection Combining, Equal Gain Combining, dan Maximal Ratio Combining untuk mendapatkan kinerja combiner yang lebih efektif dan efisien. Simulasi dilakukan dengan menggunakan modulasi BPSK pada beberapa jenis kanal yaitu Rayleigh, Rician, Nakagami-m, Weibull, dan Suzuki. Hasil simulasi MATLAB menunjukkan bahwa secara umum kanal yang mendapatkan perbaikan kinerja penerimaan, dimana nilai terendah sebesar 2 dB terjadi pada kanal Suzuki dan tertinggi sebesar 4 dB pada kanal Weibull.Kata kunci: fading, spatial diversity, rayleigh, rician, weibull, nakagami, suzuki. ABSTRACTRadio transmission channels contribute to the occurrence of fading effects that can affect the decrease in signal quality at the receiver. One solution that is used to suppress fading effects is the use of Spatial Diversity on the receiving side. In this research, a Dynamic Spatial Diversity Combining technique is used which combines Selection Combining, Equal Gain Combining, and Maximal Ratio Combining to get a more effective and efficient combiner performance. Simulation is done using BPSK modulation on several types of canals, namely Rayleigh, Rician, Nakagamim, Weibull, and Suzuki. The MATLAB simulation results show that in general canals that get improved performance, where the lowest value of 2 dB occurs on the Suzuki channel and the highest is 4 dB on the Weibull canal.Keywords: fading, spatial diversity, rayleigh, rician, weibull, nakagami, suzuki.

Image Transmission Analysis Using MIMO-OFDM Systems

2021 ◽  
pp. 157-174
Author(s):  
Akanksha Sharma ◽  
Lavish Kansal ◽  
Gurjot Singh Gaba ◽  
Mohamed Mounir
Keyword(s):  
Image Quality ◽  
Image Transmission ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Diversity Combining ◽  
Ofdm Systems ◽  
Image File ◽  
Modulation Techniques ◽  
Mimo Ofdm ◽  
Diversity Scheme

This chapter demonstrates various ways for transmitting an image file using MIMO-OFDM systems which have anti-error ability to reduce BER. Furthermore, various diversity combining techniques like maximal ratio combining (MRC), selection combining (SC) are incorporated along with transmitting diversity scheme (i.e., beamforming). Different modulation techniques (viz. QPSK, 16-PSK, and 64-PSK) are used and evaluated in terms of BER vs. SNR considering different combination of transmitters and receivers. Lastly, results showed that in the transmission course, BER is considerably reduced and the image quality is found much better in comparison to other schemes.

MIMO Modes in LTE

2019 ◽  
Vol 15 (2) ◽  
pp. 1-22
Author(s):  
Saurabh Dixit ◽  
Himanshu Katiyar ◽  
Arun Kumar Singh
Keyword(s):  
Multiple Input Multiple Output ◽  
Spatial Diversity ◽  
Spatial Multiplexing ◽  
Maximal Ratio Combining ◽  
Fourth Generation ◽  
Selection Combining ◽  
Single Input Single Output ◽  
Single Output ◽  
Input Multiple Output ◽  
Single Input

The multiple input multiple output (MIMO) technology is a key technology for fourth generation (4G) and beyond wireless communications. The MIMO exploits the space diversity to improve performance as well as augment its capacity. Long term evolution (LTE), the dominant 4G standard, operates in diverse MIMO modes, including spatial multiplexing, spatial diversity, and beamforming techniques to combine the advantages of spatial diversity and spatial multiplexing. This article discusses the various modes in LTE and analyses the performance of the single input single output (SISO) and the single input multiple output (SIMO) modes with selection combining (SC) and maximal ratio combining (MRC) at the receiver end. multiplexing (OFDM) is the multiple. The analysis was done on different values of power decay factor and the different number of channel taps. The performance of MIMO configurations for varying power delay profiles and resolvable paths has been analyzed. It is inferred that the higher number of resolvable paths and a low scattering propagating environment augments the performance.

scholarly journals On Secrecy Outage Probability for Downlink NOMA Systems With Relay-Antenna Selection

2021 ◽  
Author(s):  
Shu Xu ◽  
Chen Liu ◽  
Hong Wang ◽  
Mujun Qian ◽  
Wenfeng Sun
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Antenna Selection ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Secrecy Outage Probability ◽  
Channel State ◽  
Secrecy Outage ◽  
Secure Transmission ◽  
Theoretical Results

Abstract Secure transmission is essential for future non-orthogonal multiple access (NOMA) system. This paper investigates relay-antenna selection (RAS) to enhance physical-layer security (PLS) of cooperative NOMA system in the presence of an eavesdropper, where multiple antennas are deployed at the relays, the users, and the eavesdropper. In order to reduce expense on radio frequency (RF) chains, selection combining (SC) is employed at both the relays and the users, whilst the eavesdropper employs either maximal-ratio combining (MRC) or selection combining (SC) to process the received signals. Under the condition that the channel state information (CSI) of the eavesdropping channel is available or unavailable, two e↵ective relay-antenna selection schemes are proposed. Additionally, the closed-form expressions of secrecy outage probability (SOP) are derived for the proposed relay-antenna selection schemes. In order to gain more deep insights on the derived results, the asymptotic performance of the derived SOP is analyzed. In simulations, it is demonstrated that the theoretical results match well with the simulation results and the SOP of the proposed schemes is less than that of the conventional orthogonal multiple access (OMA) scheme obviously.

Bit Error Rate Performance Analysis of Hybrid Subcarrier Intensity Modulation-Based FSO with Spatial Diversity in Various Weather Conditions

2019 ◽  
Vol 40 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Rajat Kumar Giri ◽  
Bijayananda Patnaik
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Weather Conditions ◽  
Spatial Diversity ◽  
Intensity Modulation ◽  
Free Space Optical ◽  
Diversity Techniques ◽  
Link Distance ◽  
Simulation Results ◽  
Improved Performance

Abstract In this paper, we study the performance improvement of free space optical (FSO) communication system with spatial diversity techniques employing hybrid pulse position modulation-binary phase shift keying-subcarrier intensity modulation (PPM-BPSK-SIM). The involvement of multiple photo-detectors in diversity based FSO systems offers an effective way to overcome scntillation. In this paper, we have simulated the bit error rate (BER) with respect to different parameters like average SNR, link distance at various weather conditions. The simulation results are verified in Matlab environment with the mathematical analysis. The simulation results show that higher order single input multiple output (SIMO) system achieves better BER performance and hybrid PPM-BPSK-SIM has significant improved performance than the common modulation schemes like PPM, BPSK-SIM.

scholarly journals Reduced-Complexity Radio Architectures for Enhanced Receive Selection Combining in Multiuser Diversity Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Elpiniki P. Tsakalaki ◽  
Osama N. Alrabadi ◽  
Constantinos B. Papadias ◽  
Ramjee Prasad
Keyword(s):  
Antenna Selection ◽  
Low Cost ◽  
Spatial Diversity ◽  
Antenna System ◽  
Multiuser Diversity ◽  
Selection Combining ◽  
User Terminal ◽  
Receive Diversity ◽  
Diversity Systems ◽  
System Properties

Although antenna selection is a simple and efficient technique for enhancing the downlink performance of multiuser diversity systems, the large antenna interelement spacing required for achieving spatial diversity is prohibitive for user terminals due to size restrictions. In order to allay this problem, we propose miniaturized switched beam receiver designs assisted by low-cost passive reflectors. Unlike conventional spatial receive diversity systems, the proposed angular diversity architectures occupy a small volume whereas the antenna system properties are optimized by controlling the strong reactive fields present at small dimensions. The systems are designed for maximum antenna efficiency and low interbeam correlation, thus yieldingNpractically uncorrelated receive diversity branches. The simulation results show that the proposed enhanced diversity combining systems improve the average throughput of a multiuser network outperforming classical antenna selection especially for small user populations and compact user terminal size.

scholarly journals A Combinatorial Approach to Evaluation of Reliability of the Receiver Output for BPSK Modulation with Spatial Diversity

10.37236/1028 ◽  
2006 ◽  
Vol 13 (1) ◽  
Author(s):  
S. Bliudze ◽  
D. Krob
Keyword(s):  
Symmetric Functions ◽  
Natural Extension ◽  
Schur Functions ◽  
Digital Signal ◽  
Spatial Diversity ◽  
Phase Shift Keying ◽  
Soft Demodulation ◽  
Shift Keying ◽  
Binary Phase Shift Keying ◽  
Bpsk Modulation

In the context of soft demodulation of a digital signal modulated with Binary Phase Shift Keying (BPSK) technique and in presence of spatial diversity, we show how the theory of symmetric functions can be used to compute the probability that the log-likelihood of a recieved bit is less than a given threshold $\varepsilon$. We show how such computation can be reduced to computing the probability that $U-V < \varepsilon$ (denoted $P(U-V < \varepsilon)$) where $U$ and $V$ are two real random variables such that $U=\sum_{i=1}^N |u_i|^2$ and $V=\sum_{i=1}^N |v_i|^2$ where the $u_i$'s and $v_i$'s are independent centered complex Gaussian variables with variances ${\Bbb E}[\,|u_i|^2\,]=\chi_i$ and ${\Bbb E}[\,|v_i|^2\,]=\delta_i$. We give two expressions in terms of symmetric functions over the alphabets $\Delta=(\delta_1,\dots,\delta_N)$ and $X=(\chi_1,\dots,\chi_N)$ for the first $2N-1$ coefficients of the Taylor expansion of $P(U-V < \varepsilon)$ in terms of $\varepsilon$. The first one is a quotient of multi-Schur functions involving two alphabets derived from alphabets $\Delta$ and $X$, which allows us to give an efficient algorithm for the computation of these coefficients. The second expression involves a certain sum of pairs of Schur functions $s_\lambda(\Delta)$ and $s_\mu(X)$ where $\lambda$ and $\mu$ are complementary shapes inside a $N\times N$ rectangle. We show that such a sum has a natural combinatorial interpretation in terms of what we call square tabloids with ribbons and that there is a natural extension of the Knuth correspondence that associates a (0,1)-matrix to each square tabloid with ribbon. We then show that we can completely characterise the (0,1)-matrices that arise from square tabloids with ribbons under this correspondence.

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