Likelihood-based spectrum sensing of OFDM signals in the presence of Tx/Rx I/Q imbalance

ElSamadouny, Ahmed; Gomaa, Ahmad; Al-Dhahir, Naofal

doi:10.1109/glocom.2012.6503677

Cited by 17 publications

(11 citation statements)

References 11 publications

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“…Interestingly, in case of ϵ > 1, the TX IQI only system outperforms even the corresponding ideal RF front-end system. As can be drawn from (8) and (9), when ϵ > 1, for practical levels of IQI, it follows that |K t 1 | 2 > 1, and…”

Section: B Multi-carrier V2v Communication Systemmentioning

confidence: 98%

“…However, direct-conversion transceivers are typically sensitive to front-end related impairments, which are often inevitable due to components mismatch and manufacturing defects [7], [8] . An indicative example is the in-phase and quadrature (I/Q) imbalance (IQI) which corresponds to the amplitude and phase mismatch between the I and Q branches of a transceiver and ultimately leads to imperfect image rejection that incurs considerable performance degradation [3], [9], [10].…”

Section: Introductionmentioning

confidence: 99%

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Effects of RF Impairments in Communications Over Cascaded Fading Channels

Boulogeorgos

Sofotasios²,

Selim³

et al. 2016

IEEE Trans. Veh. Technol.

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Direct-conversion architectures can offer highly integrated low-cost hardware solutions to communication transceivers. However, it has been demonstrated that radio frequency (RF) impairments such as amplifier nonlinearities, phase noise and in-phase/quadrature-phase imbalances (IQI) can lead to a severe degradation in the performance of such systems. Motivated by this, the present work is devoted to the quantification and evaluation of the effects of RF IQI on wireless communications in the context of cascaded fading channels for both single-carrier and multi-carrier systems. To this end, closed form expressions are firstly derived for the outage probability (OP) over N *Nakagami−m channels for the cases of ideal transmitter (TX) and receiver (RX), ideal TX and IQI RX, IQI TX and ideal RX, and joint TX/RX IQI. The offered expressions along with several deduced corresponding special cases are subsequently employed in the context of vehicular-tovehicular (V2V) communications to justify their importance and practical usefulness in the context of emerging communication systems. We demonstrate that considering non-ideal RF frontends at the TX and/or RX, introduces non-negligible errors in the OP performance that can exceed 20% in several communication scenarios. We further demonstrate that the effects by cascaded multipath fading conditions are particularly detrimental, as they typically result in considerable performance losses of around or over an order of magnitude.

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Section: B Multi-carrier V2v Communication Systemmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Effects of RF Impairments in Communications Over Cascaded Fading Channels

Boulogeorgos

Sofotasios²,

Selim³

et al. 2016

IEEE Trans. Veh. Technol.

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“…In particular, the importance of improved front-end linearity and sensitivity was illustrated in [34] and [35], while the impacts of RF impairments in DCRs on single-channel energy and/or cyclostationary based sensing were discussed in [23] and [24]. Furthermore, in [36] the authors presented closed-form expressions for the detection and false alarm probabilities for the Neyman-Pearson detector, considering the spectrum sensing problem in single-channel orthogonal frequency division multiplexing (OFDM) CR RX, under the joint effect of transmitter and receiver IQI. On the other hand, multi-channel sensing under IQI was reported in [37], where a three-level hypothesis blind detector was introduced.…”

Section: Introductionmentioning

confidence: 99%

Energy Detection Spectrum Sensing Under RF Imperfections

Boulogeorgos

Chatzidiamantis

Karagiannidis

2016

IEEE Trans. Commun.

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Direct-conversion radio (DCR) receivers can offer highly integrated low-cost hardware solutions for spectrum sensing in cognitive radio (CR) systems. However, DCR receivers are susceptible to radio frequency (RF) impairments, such as in-phase and quadrature-phase imbalance, low-noise amplifier nonlinearities and phase noise, which limit the spectrum sensing capabilities. In this paper, we investigate the joint effects of RF impairments on energy detection based spectrum sensing for CR systems in multi-channel environments. In particular, we provide novel closed-form expressions for the evaluation of the detection and false alarm probabilities, assuming Rayleigh fading. Furthermore, we extend the analysis to the case of CR networks with cooperative sensing, where the secondary users suffer from different levels of RF imperfections, considering both scenarios of error free and imperfect reporting channel. Numerical and simulation results demonstrate the accuracy of the analysis as well as the detrimental effects of RF imperfections on the spectrum sensing performance, which bring significant losses in the spectrum utilization.

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“…As any other radio communication device, these transceivers also contain the RF front-end and analog-digital (A/D) interface. Several studies [11], [12], [13], have investigated the performance of spectrum sensing in shadow of RF impairments, e.g. in-phase and quadraturephase imbalance (IQI).…”

Section: Introductionmentioning

confidence: 99%

“…However, the effect of IQI in PUs in cooperative spectrum sensing has not been sufficiently studied. To the best of our knowledge, RF imperfections like IQI is considered in likelihood-based sensing [11], eigenvalue-based sensing [12] and in a three-level hypothesis blind spectrum sensing [13].…”

Section: Introductionmentioning

confidence: 99%

On the interaction between i/Q imbalance and cooperative cognitive radio spectrum sensing

Didekhani

Sadough

2015

2015 23rd Iranian Conference on Electrical Engineering

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In-phase and quadrature-phase imbalance (IQI) that is caused by direct-conversion transceivers is investigated in the context of cognitive radio (CR) systems based on energy detection. More precisely, in a cooperative CR sensing framework, we derive the optimal weighting vector for combining efficiently signals received at each CR terminal in the presence of IQI at the analog front-ends of both primary and secondary users. The deflection criterion is optimized so as to derive the linear coefficients used at the fusion center of the CR system. Numerical results are provided to analyze the effect of IQI on primary transmitter and secondary receiver.

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Likelihood-based spectrum sensing of OFDM signals in the presence of Tx/Rx I/Q imbalance

Cited by 17 publications

References 11 publications

Effects of RF Impairments in Communications Over Cascaded Fading Channels

Effects of RF Impairments in Communications Over Cascaded Fading Channels

Energy Detection Spectrum Sensing Under RF Imperfections

On the interaction between i/Q imbalance and cooperative cognitive radio spectrum sensing

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