Interference Mitigation in MIMO Systems with Imperfect CSI using Beamforming based Precoding Algorithm

Abdelkader, Hadeer Ramadan; El-Mahdy, Ahmed

doi:10.1109/icenco49778.2020.9357382

Cited by 1 publication

(3 citation statements)

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“…The pilots originating from different towers would then be separated with the help of codes rather than frequency orthogonality. Interfering pilots are either suppressed or cancelled out altogether in such an allocation [25]- [27]. The 5G-NR standards [28], for example, define the demodulation reference signal (DM-RS) sequence with such a pilot-on-pilot allocation by using orthogonal cover codes (OCCs).…”

Section: A Literature Survey 1) Channel Estimation Schemesmentioning

confidence: 99%

“…The joint detector can be formulated while including the effect of residual CFO as LLR 0,λ,k " ln ¨P ´bλ pX 0 rksq " 1 ˇˇYDrks, C1 , H1 k P ´bλ pX 0 rksq " 0 ˇˇYDrks, C1 , H1 k ¯‚ . (25) where the notation b λ p.q denotes the λ th bit of the modulated symbol on the k th subcarrier. The probabilities in the numerator and denominator would be Gaussian, assuming that the residual ICI does not much distort the noise distribution.…”

Section: ) Frequency Offset Compensation For Joint Detectormentioning

confidence: 99%

“…Bayes Theorem is applied to the joint detector formulation described in (25). LLR 0,λ,k " ln ¨P ´YD rks ˇˇbλpX0rksq"1, C1 , H1 k ¯P pb λ pX 0 rksq"1q P ´YD rks ˇˇbλpX0rksq"0, C1 , H1 k ¯P pb λ pX 0 rksq"0q ‚ (53) Summation is done over all possibilities for which b λ pX 0 rksq"1 in the numerator and b λ pX 0 rksq"0 in the denominator,assuming equal prior probabilities for constellation points.…”

Section: Appendix D Offset Corrected Joint Detectormentioning

confidence: 99%

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Interference-Aware Accurate Signal Recovery in Sub-1 GHz UHF Band Reuse-1 Cellular OFDMA Downlinks

Giridhar

2022

IEEE Open J. Commun. Soc.

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Reuse-1 systems operating in the sub-1 GHz UHF band are limited by substantial co-channel interference (CCI). In such orthogonal frequency division multiple access (OFDMA) cellular systems, the inter-sector or inter-tower interference (ITI) makes accurate signal recovery quite challenging as sub-1 GHz bands only support single-input single-output (SISO) links. Interference-aware receiver algorithms are essential to mitigate the ITI in such low-frequency bands. Such algorithms enable ubiquitous mobile broadband access over the entire homeland, say with ą 95% geographical coverage with quality of service guarantees. One element of the interference-aware signal recovery is the least-squares-based joint channel estimation scheme that uses non-orthogonal pilot subcarriers. This estimator is then compared with a variant that uses orthogonal pilot subcarriers to bring out the advantage of this joint estimator. It is shown that the proposed joint estimator requires fewer pilots to be well-determined when compared to its under-determined orthogonal counterpart. Moreover, it is easy to implement and does not require any knowledge of channel statistics. This work also derives a compensation factor needed for the interference-aware detector in the presence of inter-carrier interference (ICI) originating from multiple transmitters. Simulation results show that the proposed joint channel estimator outperforms traditional estimators at moderate to high frequency selectivity. The proposed compensation factor to the joint detector is found to be essential for recovering the transmitted signal in the absence of phase-tracking pilots.

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Section: A Literature Survey 1) Channel Estimation Schemesmentioning

confidence: 99%

Section: ) Frequency Offset Compensation For Joint Detectormentioning

confidence: 99%

Section: Appendix D Offset Corrected Joint Detectormentioning

confidence: 99%

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