Artificial frequency selective channel for covert cyclic delay diversity orthogonal frequency division multiplexing transmission

2014 ◽  
Vol 8 (9) ◽  
pp. 1707-1716 ◽  
Author(s):  
Songlin Sun ◽  
Bo Rong ◽  
Yi Qian
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Cyclic Delay Diversity ◽  
Selective Channel ◽  
Frequency Selective ◽  
Delay Diversity

Multiple-Input-Single-Output Based a Novel Pilot-Aided Channel Estimation for Cyclic Delay Diversity Orthogonal Frequency Division Multiplexing Frameworks

2019 ◽  
Vol 16 (2) ◽  
pp. 697-701
Author(s):  
D. Jagadeesan ◽  
K. Palani ◽  
G. Asha
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Low Complexity ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Cyclic Delay Diversity ◽  
Single Output ◽  
Estimation Scheme ◽  
Significant Performance ◽  
Delay Diversity

A low-complexity standard transmit diversity scheme for coded orthogonal frequency division multiplexing (OFDM) frameworks is cyclic delay diversity (CDD). As the cyclic delay esteem expands the diversity effect also increases. However, the channel estimation turns out to be more troublesome because of increased frequency selectivity as the increased cyclic delay value. In this paper we discussed about dissimilar channel estimation schemes and to conclude we proposed a novel pilot-aided channel estimation scheme for CDD to estimate the channel in an enhanced way. Our scheme estimates each channel separately and achieves significant performance improvement.

scholarly journals Practical Evaluations of SEFDM: Timing Offset and Multipath Impairments

2018 ◽  
pp. 2-9
Author(s):  
Tongyang Xu ◽  
Hedaia Ghannam ◽  
Izzat Darwazeh
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Additive White Gaussian Noise ◽  
Joint Effect ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Timing Offset ◽  
Channel Conditions ◽  
Selective Channel ◽  
Frequency Selective ◽  
The Cost

The non-orthogonal signal waveform spectrally efficient frequency division multiplexing (SEFDM) improves spectral efficiency at the cost of self-created inter carrier interference (ICI). As the orthogonal property, similar to orthogonal frequency division multiplexing (OFDM), no longer exists, the robustness of SEFDM in realistic wireless environments might be weakened. This work aims to evaluate the sensitivity of SEFDM to practical channel distortions using a professional experiment testbed. First, timing offset is studied in a bypass channel to locate the imperfection of the testbed and its impact on SEFDM signals. Then, the joint effect of a multipath frequency selective channel and additive white Gaussian noise (AWGN) is investigated in the testbed. Through practical experiments, we demonstrate the performance of SEFDM in realistic radio frequency (RF) environments and verify two compensation methods for SEFDM. Our results show first frequency-domain compensation works well in frequency non-selective channel conditions while time-domain compensation method is suitable for frequency selective channel conditions. This work paves the way for the application of SEFDM in different channel scenarios.

The Diversity Gains of Amplify-and-Forward Relay System with Frequency Selective Channels

2014 ◽  
Vol 644-650 ◽  
pp. 4297-4302
Author(s):  
Y.H. Ding ◽  
R.J. Tian ◽  
K. Xue ◽  
Y. Tian ◽  
X.C. Wang ◽  
...  
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Amplify And Forward ◽  
Relay System ◽  
Relay Systems ◽  
Frequency Selective ◽  
Multiple Relay ◽  
Frequency Selective Channels ◽  
Diversity Gains

The diversity gains of amplify-and-forward (AF) relay system with frequency selective channels are discussed. The orthogonal frequency division multiplexing (OFDM) is applied to overcome the inter-symbol interference. The diversity gains are presented for single and multiple relay systems with detailed derivations.

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