Channel equalization with staggered modulation formats

López-Valcarce, Roberto

doi:10.1109/icdsp.2002.1028204

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…This is a desirable feature when non-linear amplifiers are used (efficient amplification) since it prevents side lobes regeneration and reduces interchannel interference. The minimum sampling rate required for staggered modulation formats determines a certain complexity which can not be reduced on expense of performance [4]. The equalizers for OQPSK or GMSK that were considered were based on sampling the signal in the bit rate, i.e.…”

Section: Introductionmentioning

confidence: 99%

A Reduced complexity equalizer for OQPSK

Raphaeli

Suissa

2008

2008 3rd International Symposium on Communications, Control and Signal Processing

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In this paper a reduced complexity equalizer for Offset-QPSK (OQPSK), GMSK, or any other staggered modulation formats is presented. It is known that for OQPSK, due to the relative time offset of the in-phase and quadrature components, the received signal must be sampled at twice the baud rate of its corresponding non-staggered signal. This doubles the number of equalizer coefficients required, relative to QPSK, where using a symbol-spaced equalizer is an option. In this work it is shown that it is possible to implement an equalizer, for OQPSK, with about half the complexity normally required for the linear equalizer or for the feed forward filter in Decision Feedback Equalizer. By this, an option for a symbol-spaced equalizer for OQPSK is actually introduced for the first time. Both MMSE and DFE are treated in this work. We test the sensitivity to timing and propose a novel matched filter approximation that avoids the need of timing compensation.978-1-4244-1688-2/08/$25.00 c 2008 IEEE

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Section: Introductionmentioning

confidence: 99%

A Reduced complexity equalizer for OQPSK

Raphaeli

Suissa

2008

2008 3rd International Symposium on Communications, Control and Signal Processing

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A Reduced Complexity Equalizer for OQPSK

Raphaeli

2010

IEEE Trans. Commun.

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SC-FDE for Offset Modulations: An Efficient Transmission Technique for Broadband Wireless Systems

Luzio

Dinis

Montezuma

2012

IEEE Trans. Commun.

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It is widely accepted that SC-FDE (Single-Carrier with Frequency-Domain Equalization) is an excellent candidate for broadband wireless systems, especially when an efficient power amplification is intended. If grossly nonlinear power amplifiers are employed, conventional QPSK (Quaternary Phase Shift Keying) or QAM (Quadrature Amplitude Modulation) modulations should be replaced by offset modulations such as OQPSK (Offset QPSK) and OQAM (Offset QAM). In fact, offset signals have much lower dynamic range than non-offset signals, with OQPSK signals being able to have an almost constant envelope. This paper considers frequency-domain receiver design for OQPSK and OQAM schemes. It is shown that FDE (Frequency Domain Equalization) designed for non-offset modulations are not suitable for offset modulations due to the residual IQI (Inphase/Quadrature Interference), i.e. the interference between in-phase (I) and quadrature (Q) components at the sampling instants. Therefore, we propose several FDE designs where there is no IQI in the sampling instants as well as iterative FDE receivers with IQI cancellation. Our receivers have excellent performance, with the linear designs significantly outperforming linear FDE for non-offset modulations and the iterative designs with performance close to the MFB (Matched Filter Bound).

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Channel equalization with staggered modulation formats

Cited by 3 publications

References 8 publications

A Reduced complexity equalizer for OQPSK

A Reduced complexity equalizer for OQPSK

A Reduced Complexity Equalizer for OQPSK

SC-FDE for Offset Modulations: An Efficient Transmission Technique for Broadband Wireless Systems

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