I/Q Imbalance in Multiple Beamforming {OFDM} Transceivers: SINR Analysis and Digital Baseband Compensation

Özdemir, Özgür; Hamila, Ridha; Al-Dhahir, Naofal

doi:10.1109/tcomm.2013.021913.120321

Cited by 37 publications

(34 citation statements)

References 20 publications

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“…For example, approximate SINR analysis for OFDM systems under high mobility is reported in [1]. For multiple-antenna OFDM systems, approximate SINR analysis for MIMO spatial multiplexing, space-time coded OFDM systems, and MIMO beamforming can be found in [2], [3], and [4], respectively.…”

Section: Introductionmentioning

confidence: 99%

Exact SINR analysis of OFDM systems under joint Tx/RX I/Q imbalance

Özdemir

Hamila

Al-Dhahir³

2013

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC)

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The direct-conversion architecture used for Orthogonal Frequency Division Multiplexing (OFDM) systems suffers from intercarrier interference (ICI) between image subcarriers in each OFDM symbol due to I/Q imbalance between the inphase (I) and quadrature (Q) branches at the transmit and receive sides. One of the widely-used metrics to evaluate the performance degradation due to I/Q imbalance is the signal to interference plus noise ratio (SINR). The instantaneous subcarrier SINR can be represented as a ratio conditioned on a particular channel realization and the exact SINR is evaluated by averaging over the channel realizations. In the literature, it is common to approximate the SINR by taking the average of the numerator and denominator separately although the two are not independent. In this paper, we calculate the exact SINR under the assumption that each pair of interfering subcarriers experiences uncorrelated channel realizations. We show that the SINR grows as the logarithm of the input SNR when the receiver has I/Q imbalance. On the other hand, under transmit-only I/Q imbalance, there is an SINR ceiling for large input SNR. Therefore, transmitter side I/Q imbalance is more harmful, in terms of average SINR, than receiver-only I/Q imbalance. We also show that, the approximate SINR expression, commonly used in the literature, is not accurate for large input SNR values, except for the case of transmit-only I/Q imbalance.

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Section: Introductionmentioning

confidence: 99%

Exact SINR analysis of OFDM systems under joint Tx/RX I/Q imbalance

Özdemir

Hamila

Al-Dhahir³

2013

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC)

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“…The signal leakage naturally makes the signal separation in the RX more difficult and consequently the overall system performance is also deteriorated, as shown in Section IV. The signal distortion, where each subcarrier signal is mixed with the signals at the image subcarrier, guides us towards joint post-processing of mirror-subcarriers [6]- [8]. When defining the augmented received signal as …”

Section: Tx+rx I/q Imbalances Becomesmentioning

confidence: 99%

Precoded massive MU-MIMO uplink transmission under transceiver I/Q imbalance

Hakkarainen

Werner

Dandekar

et al. 2014

2014 IEEE Globecom Workshops (GC Wkshps)

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In massive multiple-input multiple-output (MIMO) systems, combined with digital array processing, the amount of the associated radio frequency (RF) front-ends is inevitably high. This paper addresses how imperfections in these RF front-ends affect the overall system performance in precoded massive multiuser MIMO (MU-MIMO) uplink transmission. In particular, we focus on transceiver in-phase/quadrature (I/Q) imbalances and their mitigation with RF-aware spatial processing. We first derive the essential distortion and interference models for OFDMAbased massive MU-MIMO uplink system under I/Q imbalances, and then propose augmented spatial post-processing to be carried out in the uplink receiver (RX) for mitigating the harmful effects efficiently. Numerical examples show that the augmented spatial RX processing clearly outperforms the conventional linear processing, and thus provides significant performance improvements with practical low-cost RF front-ends.Index Terms-antenna arrays, in-phase/quadrature (I/Q) imbalance, interference suppression, massive multi-user multipleinput multiple-output (MU-MIMO), orthogonal frequencydivision multiple access (OFDMA)

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“…where the ratio κ |B| 2 / |A| 2 is referred to as the joint image-leakage ratio of the considered relaying system [9], [12], [13]. Note that for the case of perfect I/Q matching at the relay node, we have A = 1, B = 0 and κ = 0.…”

Section: B End-to-end Snrmentioning

confidence: 99%

I/Q imbalance in two-way AF relaying: Power allocation and performance analysis

Matthaiou

Svensson

2014

2014 IEEE International Conference on Communications (ICC)

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We investigate the performance of dual-hop twoway amplify-and-forward (AF) relaying in the presence of inphase and quadrature-phase imbalance (IQI) at the relay node. In particular, the effective signal-to-interference-plus-noise ratio (SINR) at both sources is derived. These SINRs are used to design an instantaneous power allocation scheme, which maximizes the minimum SINR of the two sources under a total transmit power constraint. The solution to this optimization problem is analytically determined and used to evaluate the outage probability (OP) of the considered two-way AF relaying system. Both analytical and numerical results show that IQI can create fundamental performance limits on two-way relaying, which cannot be avoided by simply improving the channel conditions.

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I/Q Imbalance in Multiple Beamforming {OFDM} Transceivers: SINR Analysis and Digital Baseband Compensation

Cited by 37 publications

References 20 publications

Exact SINR analysis of OFDM systems under joint Tx/RX I/Q imbalance

Exact SINR analysis of OFDM systems under joint Tx/RX I/Q imbalance

Precoded massive MU-MIMO uplink transmission under transceiver I/Q imbalance

I/Q imbalance in two-way AF relaying: Power allocation and performance analysis

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