Efficient Discrete Simulation of Coded Wireless Communication Systems

Author(s):  
Pedro J.A. Sebastião ◽  
Francisco A.B. Cercas ◽  
Adolfo V.T. Cartaxo

Simulation can be a valuable tool for wireless communication system’s (WCS) designers to assess the performance of its radio interface. It is common to use the Monte Carlo simulation method (MCSM), although this is quite time inefficient, especially when it involves forward error correction (FEC) with very low bit error ratio (BER). New techniques were developed to efficiently evaluate the performance of the new class of TCH (Tomlinson, Cercas, Hughes) codes in an additive white Gaussian noise (AWGN) channel, due to their potential range of applications. These techniques were previously applied using a satellite channel model developed by Lutz with very good results. In this chapter, we present a simulation method, named accelerated simulation method (ASM), that provides a high degree of efficiency and accuracy, namely for lower BER, where the application of methods like the MCSM is prohibitive, due to high computational and time requirements. The present work generalizes the application of the ASM to a WCS modelled as a stochastic discrete channel model, considering a real channel, where there are several random effects that result in random energy fluctuations of the received symbols. The performance of the coded WCS is assessed efficiently, with soft-decision (SD) and hard-decision (HD) decoding. We show that this new method already achieves a time efficiency of two or three orders of magnitude for SD and HD, considering a BER = 1x10-4 , when compared to MCSM. The presented performance results are compared with the MCSM, to check its accuracy.

2020 ◽  
Vol 23 (1) ◽  
pp. 159-171
Author(s):  
Ahmad Baheej

The multipath phenomenon is a major factor that is continually affected negatively the performance of wireless communication systems. Since the receiver gets different copies of the transmitted signal from various paths at different times. Consequently, destructive or constructive interference can occur. Therefore, the performance of wireless communication systems is poor in term of bit error rate. This phenomenon can be taken as an advantage if the multiple – input – multiple – output antenna systems are employed at both transmitter and receiver sides (antenna diversity) to improve the bit error rate performance. This paper focuses on the combination of multipath forward error correction diversity technique with vertical-Bell laboratories layered space-time coding. This will lead to enhance the bit error rate in wireless communication systems. The proposed system used Rayleigh and additive white Gaussian noise as two different channel models. The multipath forward error correction diversity technique treats the multipath propagated signals as unessential copies, to utilise them to enhance the bit error rate limitation in the multiple – input – multiple – output systems. The simulation results showed that the performance of the proposed system can be gradually improved by increasing the number of utilised multipath signals in the multipath forward error correction diversity technique


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Ahmed Nabih Zaki Rashed ◽  
A.H.M Shahariar Parvez ◽  
Bikash Kumar Paul ◽  
Kawsar Ahmed

AbstractThe study has outlined the different correction codes based optical wireless communication channel and security management in free space optics communication systems. The used codes that are namely forward error correction (FEC) code, Reed Solomon (RS) code, and Redundancy check (RC) code. The output power, maximum Q-parameter coefficient and minimum data error rates are estimated with these codes with variations of input signal power and propagation distances. The performance of optical wireless channel is enhanced with FEC code in compared to other proposed codes under the same operating conditions.


Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 400
Author(s):  
Bin Chen ◽  
Yi Lei ◽  
Gabriele Liga ◽  
Chigo Okonkwo ◽  
Alex Alvarado

Coded modulation (CM), a combination of forward error correction (FEC) and high order modulation formats, has become a key part of modern optical communication systems. Designing CM schemes with strict complexity requirements for optical communications (e.g., data center interconnects) is still challenging mainly because of the expected low latency, low overhead, and the stringent high data rate requirements. In this paper, we propose a CM scheme with bit-wise hard-decision FEC and geometric shaping. In particular, we propose to combine the recently introduced soft-aided bit-marking decoding algorithm for staircase codes (SCCs) with geometrically-shaped constellations. The main goal of this CM scheme is to jointly boost the coding gain and provide shaping gain, while keeping the complexity low. When compared to existing CM systems based on M-ary quadrature-amplitude modulation (MQAM, M = 64 , 128 , 256 ) and conventional decoding of SCCs, the proposed scheme shows improvements of up to 0 . 83 dB at a bit-error rate of 10 - 6 in the additive white Gaussian noise channel. For a nonlinear optical fiber system, simulation results show up to 24 % reach increase. In addition, the proposed CM scheme enables rate adaptivity in single-wavelength systems, offering six different data rates between 450 Gbit/s and 666 Gbit/s.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kai Zhang ◽  
Fangqi Zhang ◽  
Guoxin Zheng ◽  
Lei Cang

With the rapid development of high-mobility wireless communication systems, e.g., high-speed train (HST) and metro wireless communication systems, more and more attention has been paid to the wireless communication technology in tunnel-like scenarios. In this paper, we propose a three-dimensional (3D) nonstationary multiple-input multiple-output (MIMO) channel model with high-mobility wireless communication systems using leaky coaxial cable (LCX) inside a rectangular tunnel over the 1.8 GHz band. Taking into account single-bounce scattering under line-of-sight (LoS) and non-line-of-sight (NLoS) propagations condition, the analytical expressions of the channel impulse response (CIR) and temporal correlation function (T-CF) are derived. In the proposed channel model, it is assumed that a large number of scatterers are randomly distributed on the sidewall of the tunnel and the roof of the tunnel. We analyze the impact of various model parameters, including LCX spacing, time separation, movement velocity of Rx, and K-factor, on the T-CF of the MIMO channel model. For HST, the results of some further studies on the maximum speed of 360 km/h are given. By comparing the T-CF between the dipole MIMO system and the LCX-MIMO system, we can see that the performance of the LCX-MIMO system is better than that of the dipole MIMO system.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Jiangnan Xiao ◽  
Xu Dong ◽  
Bo Liu ◽  
Xingxing Feng ◽  
Chuang Zhao ◽  
...  

In this paper, we introduce the probabilistic shaping (PS) technique to the normal (3, 1) vector signal and simulate the generated PS (3, 1) photonic vector signal on an optical transmission system. The PS (3, 1) photonic vector signal is generated by a radio frequency (RF) signal at 12 GHz driving a Mach–Zehnder modulator- (MZM-) based optical carrier suppression (OCS) doubling, and the PS (3, 1) photonic vector signal is not precoding. The PS (3, 1) photonic vector signal and the normal (3, 1) photonic vector signal are used to transmit in 5 km, 10 km, and 20 km single-mode fibers (SMF), respectively. The simulation results demonstrate that the bit error ratio (BER) of the PS (3, 1) vector signal is less than the forward error correction (FEC) threshold of 3.8  ×  10−3, and the BER performance is better than that of the normal (3, 1) vector signal at 4 Gbit/s and 8 Gbit/s transmission rates.


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