Interference Mitigation in Turbo-Coded OFDM Systems Using Robust LLRs

Kalyani, Sheetal; Giridhar, K.

doi:10.1109/icc.2008.127

Cited by 14 publications

(14 citation statements)

References 13 publications

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“…In this case, we can detect all superposed bands with high probability even if some of them are misdetected in Eq. (19). However, nonsuperposed bands also have a tendency to be detected as superposed bands.…”

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

“…When z(l) does not exceed |r th | 2 , l is detected as a non-superposed band in Eq. (19). However, when P if (l) exceeds 0.5, we discard the previous result and detect l as a superposed band.…”

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

“…The subcarrier corresponding to the red plot is misdetected as a non-superposed band in Eq. (19), because it is smaller than the threshold. Under the superposed band detection based on the superposition probabilities, we can fix the misdetection when the superposition probability of only the red plot is larger than 0.5 among all the plots smaller than the threshold.…”

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

“…Similarly, we detect l as a non-superposed band when P if (l) does not exceed 0.5, irrespective of the result in Eq. (19). Namely,…”

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

“…Since interference parameters are usually unknown to the receiver, robust LLR is proposed in [19], which weights two PDFs by a coefficient to take interferences into account. As robust LLR is tolerant toward variation of interference parameters, in [15,19], the interference power and the coefficient are set to 4 and 0.3, respectively, as constant values. However, there are some points to be mentioned.…”

Section: System Modelmentioning

confidence: 99%

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Suppression of multiple wideband interferences based on superposition probability

Kakizaki

Shibata

Ohtsuki

et al. 2016

J Wireless Com Network

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Superposed multicarrier transmission is one of the schemes that achieve efficient use of frequency resources. In the scheme, desired signals are interfered by other systems sharing the same frequency band, which causes unreliable LLR (log-likelihood ratio) setting and leads to degradation of the BER (bit error rate) performance. In many conventional schemes for OFDM (orthogonal frequency division multiplexing) systems, the interference power for each subcarrier is estimated independently. Otherwise, based on the assumption that interferences have the same average power, one interference power is estimated and applied to all subcarriers. However, when there exist multiple wideband interferences with different average power, it is better to detect each interference and estimate each power based on all subcarriers within each superposed band to make it accurate. In this paper, we propose a scheme to suppress multiple wideband interferences based on the probability with which each subcarrier is superposed, referred to as the superposition probability. In the proposed scheme, we derive the PDFs (probability density functions) of residual powers for superposed and non-superposed bands. Based on residual powers and their PDFs, we calculate the superposition probability for each subcarrier. Furthermore, we perform superposed band detection iteratively according to the probabilities and update each estimated interference power. Through simulations, we show that the detection rate of superposed bands is improved by iterating superposed band detection based on superposition probabilities. We also show that the proposed scheme achieves the better BER performance than that of conventional ones.

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Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

“…Similarly, we detect l as a non-superposed band when P if (l) does not exceed 0.5, irrespective of the result in Eq. (19). Namely,…”

Section: Iterative Superposed Band Detection Based On Superposition Pmentioning

confidence: 99%

Section: System Modelmentioning

confidence: 99%

See 3 more Smart Citations

Suppression of multiple wideband interferences based on superposition probability

Kakizaki

Shibata

Ohtsuki

et al. 2016

J Wireless Com Network

View full text Add to dashboard Cite

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A Novel Signal Detector in MIMO Systems Based on Complex Correntropy

et al. 2019

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In cellular systems, information signals must be transmitted at high rates and with high reliability. One of the possible solutions to meet such criteria is the use of systems with multiple transmitting and/or receiving antenna arranged in the form of a multiple-input, multiple-output (MIMO) system. However, signal processing techniques in MIMO systems are developed under the assumption of transmission on Gaussian channels, which may lead to the decrease of efficiency in non-Gaussian communication scenarios. In this context, the widespread use of MIMO systems in recent years has motivated the development of new processing techniques that can be employed in scenarios that also consider the presence of non-Gaussian noise in communication channels. This work proposes a novel signal detection technique for MIMO systems, which is called maximum correntropy detector (MCD), being adequate to environments characterized by Gaussian and non-Gaussian noise. The introduced approach is based on complex correntropy function and can be seen as a generalization of the maximum likelihood detector (MLD) concept. The MCD is evaluated on Gaussian and non-Gaussian channels, where superior performance is achieved when compared with the classic detectors, without significant increase of the computational complexity.

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