Iterative Frequency-Domain Equalization for general constellations

Dinis, Rui; Montezuma, Paulo; Souto, Nuno; Silva, Joao

doi:10.1109/sarnof.2010.5469792

Cited by 55 publications

(37 citation statements)

References 10 publications

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“…In practice, g 0 = 0, since it is the center of mass of the constellation; moreover, several other g i can also be 0 [7] (e.g., for a 64-QAM constellation with Gray mappings we have only 6 nonzero g i coefficients: g 4 = 4, g 6 = 2, g 7 = 1, g 32 = 4j, g 48 = 2j and g 56 = j). If we denote M m the number of nonzero coefficients g i coefficients, then it is clear that a given constellation can be decomposed as the sum of N m ≤ M polar components.…”

Section: Transmitter Structurementioning

confidence: 99%

“…To allow highly efficient, strongly nonlinear power amplifiers, the variable envelope signals associated to large constellations is decomposed as the sum of several polar components [7], each one modulated as a serial OQPSK signal [8] with reduced envelope fluctuations that is amplified and transmitted by a separate antenna within a massive MIMO scheme. A pragmatic receiver for offset modulations [9], which is based on the IB-DFE concept (Iterative Block Decision Feedback Equalization) [10] is also considered.…”

Section: Introductionmentioning

confidence: 99%

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A multi-antenna technique for mm-wave communications with large constellations and strongly nonlinear amplifiers

Dinis

Montezuma

Bento

et al. 2015

2015 German Microwave Conference

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It is well-known that mm-wave (millimeter wave) communications have high potential for future wireless broadband systems. However, there are important challenges that need to be overcome when implementing those systems, both at the hardware level and due to the hostile propagation conditions. This is especially important for spectrally efficient communications based on large constellations, since the power requirements are higher, as well as the amplification difficulties, specially for large, dense constellations.In this paper we propose a multi-antenna transmitter combined with a frequency-domain receiver for broadband mm-wave systems based on large and dense constellations. Our transmitter is compatible with highly-efficient, low-cost, strongly nonlinear amplifiers, while allowing spacial multiplexing gains. 1

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Section: Transmitter Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A multi-antenna technique for mm-wave communications with large constellations and strongly nonlinear amplifiers

Dinis

Montezuma

Bento

et al. 2015

2015 German Microwave Conference

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“…For this purpose, we just need to employ the generalized IB-DFE design of references [29,30]. The hard decision associated to the symbol S k,n isŜ k;n ¼ sign…”

Section: Ib-dfe Sic Approachmentioning

confidence: 99%

“…For larger constellations, an estimate of the correlation coefficient can be computed as in [29,30]. For a given iteration and the detection of the kth UE, the iterative receiver equalizer is composed by coefficients F i ð Þ k;l and B i ð Þ k;l .…”

Section: Ib-dfe Sic Approachmentioning

confidence: 99%

Performance evaluation of IB-DFE-based strategies for SC-FDMA systems

Silva

Assunção

Dinis

et al. 2013

J Wireless Com Network

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The aim of this paper is to propose and evaluate multi-user iterative block decision feedback equalization (IB-DFE) schemes for the uplink of single-carrier frequency-division multiple access (SC-FDMA)-based systems. It is assumed that a set of single antenna users share the same physical channel to transmit its own information to the base station, which is equipped with an antenna array. Two space-frequency multi-user IB-DFE-based processing are considered: iterative successive interference cancellation and parallel interference cancellation. In the first approach, the equalizer vectors are computed by minimizing the mean square error (MSE) of each individual user, at each subcarrier. In the second one, the equalizer matrices are obtained by minimizing the overall MSE of all users at each subcarrier. For both cases, we propose a simple yet accurate analytical approach for obtaining the performance of the discussed receivers. The proposed schemes allow an efficient user separation, with a performance close to the one given by the matched filter bound for severely time-dispersive channels, with only a few iterations.

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“…As so, the use of offset signals such as OQPSK particularly suits LINC, since it is known that these can have much lower envelope fluctuations than non-offset signals. In fact, recently, new architectures have been proposed for 5G [7], [8] employing multi-layer massive antenna structures allowing for highly power and spectral efficient transmitters leverage on the the use of large constellations (e.g., 16-QAM or 64-QAM) that are decomposed as a sum of several OQPSK-type signals [9]; these OQPSK components can individually be efficiently amplified by using LINC and transmitted separately through different antennas. However, compact spectrum OQPSK signals (e.g., trough a square-root raised-cosine filtering with small roll-off) can possess significant envelope fluctuations which may impact on LINC combiner efficiency; in fact, OQPSK-type signals can only have constant envelope at the expense of bandwidths much wider than the minimum Nyquist band (e.g.…”

Section: Introductionmentioning

confidence: 99%

Boosting LINC systems combiners efficiency through ring-type magnitude modulation

Castanheira

Simioes

Gomes

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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Abstract-This paper proposes a transmitter structure that combines a ring-type magnitude modulation (RMM) technique with a linear amplification with nonlinear components (LINC) scheme for power and spectrally efficient transmission based on bandwidth limited OQPSK signals, for either a linear combiner (LC) or a Chireix combiner (CC). It shows that by controlling the transmitted signal's envelope through RMM, the range of the LINC decomposition angle is considerably decreased. This significantly improves LC's power efficiency, and substantially reduces CC's spectral leakage while maintaining its high amplification efficiency.

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Iterative Frequency-Domain Equalization for general constellations

Cited by 55 publications

References 10 publications

A multi-antenna technique for mm-wave communications with large constellations and strongly nonlinear amplifiers

A multi-antenna technique for mm-wave communications with large constellations and strongly nonlinear amplifiers

Performance evaluation of IB-DFE-based strategies for SC-FDMA systems

Boosting LINC systems combiners efficiency through ring-type magnitude modulation

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