scholarly journals Impact of Uncertain Channel Estimation and Outdated Feedback on the Adaptive M-PSK Modulation

2014 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Mohamed L. Ammari ◽  
Francois Gagnon
Keyword(s):  
Channel Estimation ◽  
Estimation Error ◽  
Error Variance ◽  
Channel Estimation Error ◽  
Closed Form Expression ◽  
Modulation Scheme ◽  
Form Expression ◽  
Pilot Symbols ◽  
Modulation Techniques ◽  
Modulation Level

This paper investigates an adaptive M-ary phaseshiftkeying (M-PSK) modulation scheme over Rayleigh flatfading channels. The data rate is adapted according to thechannel state. At the receiver, the fading is estimated using pilot symbols. To cancel the channel impact, we correct the received signal by dividing it by the estimated value of the fading. So, we propose to adjust the modulation level by examining the statistics of the corrected signal. In contrast to the previous works on the adaptive M-PSK modulation techniques, our modulation switching protocol takes into account the channel estimation error variance. Moreover, we derive a new closed-form expression for the average bit error rate of the considered system.

scholarly journals Block-Type Pilot Arrangement with Alternating Polarity for ICI Mitigation in Mobile OFDM Systems

2013 ◽  
Vol 9 (3) ◽  
pp. 178 ◽  
Author(s):  
Titiek Suryani ◽  
Gamantyo Hendrantoro
Keyword(s):  
Channel Estimation ◽  
Doppler Shift ◽  
Channel Model ◽  
Estimation Error ◽  
Least Square ◽  
Channel Estimation Error ◽  
Piecewise Linear Approximation ◽  
Modulation Scheme ◽  
Block Type ◽  
Time Varying

Improvement on Inter Carrier Interference (ICI)mitigation techniques for OFDM caused by Doppler effectsthrough minimizing channel estimation error and decreasingchannel time varying rate is investigated. The performanceof pilot-aided channel estimation techniques depends on pilot placement and arrangement and also on the channel time varying rate. The block-type and comb-type pilot arrangements are studied through different numbers of guard bands, with or without the involvement of the Doppler shift compensation. The estimation of channel at mid-point of each OFDM symbol is derived from pilot frequencies based on the least square algorithm while the channel interpolation is done using piecewise linear approximation. For ICI mitigation technique we implement frequency domain zero forcing equalizer. We compare the performance of schemes with different pilot arrangementsand Doppler shift compensations by measuring bit error rate with QPSK as sub-channel modulation scheme and with mobileto-fixed of single ring scattering as channel model. The results are in favour of block-type pilot arrangements with alternating polarity and Doppler compensation of 0:55 times the maximum Doppler shift.

scholarly journals Visible Light Communication with Input-Dependent Noise: Channel Estimation, Optimal Receiver Design and Performance Analysis

2021 ◽  
Author(s):  
MAYSA YASEEN ◽  
Malek Alsmadi ◽  
Ayse E. Canbilen ◽  
salama Ikki
Keyword(s):  
Channel Estimation ◽  
Visible Light ◽  
Data Transmission ◽  
Estimation Error ◽  
Visible Light Communication ◽  
Least Square ◽  
Channel Estimation Error ◽  
Closed Form Expression ◽  
Optimal Receiver ◽  
Ber Performance

<div>In this paper, single-input single-output (SISO) visible light communication (VLC) subject to signal-dependent shot noise (SDSN) is investigated. We discuss both channel estimation and data transmission. In the former, we introduce least square (LS) and maximum likelihood (ML) estimators. Moreover, we derive the Cram´er–Rao lower bound (CRLB) of the channel estimation error. With regard to data transmission, we present optimal and sub-optimal receiver designs and discuss their bit error rate (BER) performance. In particular, a closed-form expression of the BER is derived for a sub-optimal receiver using the on-off-keying (OOK) modulation technique. An approximated expression is then derived for the optimal receiver. Our analysis shows that the CRLB performance does not have a linear relation with the SDSN, thermal noise, or the fading channel. On the other hand, the SDSN has a dramatic effect on the channel estimation error bound, and it can degrade the BER performance. Increased performance degradation can also be noticed due to the joint effects of the channel estimation error and SDSN.</div>

scholarly journals Secrecy capacity optimization artificial noise: the ergodic secrecy capacity lower bound and optimal power allocation

2020 ◽  
Author(s):  
Yebo Gu ◽  
Zhilu Wu ◽  
Zhendong Yin ◽  
Bowen Huang
Keyword(s):  
Lower Bound ◽  
Channel Estimation ◽  
Closed Form ◽  
Power Allocation ◽  
Estimation Error ◽  
Closed Form Expression ◽  
Artificial Noise ◽  
Secrecy Capacity ◽  
Capacity Optimization ◽  
Form Expression

Abstract The secure transmission problem of MIMO wireless system in fading channels is studied in this paper. We add a secrecy capacity optimization artificial noise(SCO-AN) to the transported signal for improving the security performance of the system. The closed-form expression of secrecy capacity's lower bound is obtained. Base on the closed-form expression of secrecy capacity's lower bound, We optimize the power allocation between the information-bearing signal and the SCO-AN. By calculating, the optimal ratio of power alloation betwenn the information-bearing signal and the SCO-AN is obtained. Through simulation, the results shows the secrecy capacity increases with more receiving antennas and less eavesdropping antennas.And more power should be allocated to the SCO-AN with the increase of the colluding eavedroppers.More over, we study the effect of channel estimation error on power allocation between information-bearing signal and SCO-AN and find that more power should be allocated to decrease eavesdroppers capacity if the channel estimation is not perfect.

scholarly journals Visible Light Communication with Input-Dependent Noise: Channel Estimation, Optimal Receiver Design and Performance Analysis

2021 ◽  
Author(s):  
MAYSA YASEEN ◽  
Malek Alsmadi ◽  
Ayse E. Canbilen ◽  
salama Ikki
Keyword(s):  
Channel Estimation ◽  
Visible Light ◽  
Data Transmission ◽  
Estimation Error ◽  
Visible Light Communication ◽  
Least Square ◽  
Channel Estimation Error ◽  
Closed Form Expression ◽  
Optimal Receiver ◽  
Ber Performance

<div>In this paper, single-input single-output (SISO) visible light communication (VLC) subject to signal-dependent shot noise (SDSN) is investigated. We discuss both channel estimation and data transmission. In the former, we introduce least square (LS) and maximum likelihood (ML) estimators. Moreover, we derive the Cram´er–Rao lower bound (CRLB) of the channel estimation error. With regard to data transmission, we present optimal and sub-optimal receiver designs and discuss their bit error rate (BER) performance. In particular, a closed-form expression of the BER is derived for a sub-optimal receiver using the on-off-keying (OOK) modulation technique. An approximated expression is then derived for the optimal receiver. Our analysis shows that the CRLB performance does not have a linear relation with the SDSN, thermal noise, or the fading channel. On the other hand, the SDSN has a dramatic effect on the channel estimation error bound, and it can degrade the BER performance. Increased performance degradation can also be noticed due to the joint effects of the channel estimation error and SDSN.</div>

Influence of Channel Estimation Error on MIMO Multiplexing Using Precoding in Downlink OFDM Radio Access

2009 ◽  
Vol E92-B (5) ◽  
pp. 1553-1562
Author(s):  
Takashi ISOGAI ◽  
Mamoru SAWAHASHI ◽  
Hidekazu TAOKA ◽  
Kenichi HIGUCHI
Keyword(s):  
Channel Estimation ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Radio Access
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