Widely linear equalization for space-time block-coded transmission over fading ISI channels

Gerstacker, Wolfgang H.; Obernosterer, F.; Schober, Robert; Lehmann, A.; Lampe, A.; Gunreben, P.

doi:10.1109/vetecf.2002.1040340

Cited by 10 publications

(7 citation statements)

References 15 publications

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“…When all users are synchronized with the base station (BS) clock rate and all signals arrive within the CP and CS duration at the receive antennas, space-time combining according to (9) can be carried out per user, where only the users' allocated frequency samples are considered. However, CSI including misalignment information needs to be available at the BS.…”

Section: Timing Misalignment and Channel Estimationmentioning

confidence: 99%

“…Instead, using only the first transmit antenna is equivalent to have h 2,l = 0. In this case, the transmitted signal can still be recovered; however, according to (9), no transmit diversity gain is achieved. For example, users with cheap devices or very good channel conditions would not carry out the spacetime encoding but can still be correctly received by the BS.…”

Section: Timing Misalignment and Channel Estimationmentioning

confidence: 99%

“…With the application of TR-STC, the error floor due to multipath ISI is completely removed because space-time combining is performed in the signal domain rather than in the data domain. Also, the system complexity is kept low compared to more elaborate equalization techniques in the data domain [9].…”

Section: Introductionmentioning

confidence: 99%

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Multi-user time-reversal STC-GFDMA for future wireless networks

Matthé

Mendes

Gaspar

et al. 2015

J Wireless Com Network

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The challenges of future wireless networks imply that the physical layer of the next generation mobile communication system needs to be compatible with multiple-input multiple-output and allow a flexible multiple access scheme. Time-reversal space-time coding can be applied to a recent filtered multicarrier modulation scheme, named generalized frequency division multiplexing, to achieve a multiple-input multiple-output non-orthogonal multicarrier modulation with flexibility to address the requirements of future mobile networks. In this paper, the subcarriers of the physical layer block are shared between multiple users, allowing for an efficient and simple multiple access solution. A channel estimation technique that can simultaneously estimate channel frequency response and timing misalignment in generalized frequency division multiple access is described. The paper also shows that the knowledge of channel state information can improve the overall performance when used to schedule the subchannel distribution among the users. Symbol error rate performance analysis shows that the resources of the time-reversal space-time coding generalized frequency division multiple access block can be shared among users that have one or two transmit antennas simultaneously under frequency-selective time-variant channels.

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Section: Timing Misalignment and Channel Estimationmentioning

confidence: 99%

Section: Timing Misalignment and Channel Estimationmentioning

confidence: 99%

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Multi-user time-reversal STC-GFDMA for future wireless networks

Matthé

Mendes

Gaspar

et al. 2015

J Wireless Com Network

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“…One important aspect of this technique is the fact that it takes advantage of frequency diversity since signal spreading is performed purely in the frequency domain, making possible to use diversity combining based techniques for signal detection [3]. To also explore space and time diversity in order to help mitigate channel's frequency selective fading, STBC (Space-Time Block Codes) have been proposed [4]. One of the simplest schemes is the Alamouti space-time code [5] which does not require very complex decoders and can be integrated in the existing systems without needing much redesign.…”

Section: Introductionmentioning

confidence: 99%

Performance of extended space-time coding techniques for MIMO MC-CDMA systems

Bastos

Gameiro

2006

2006 First European Conference on Antennas and Propagation

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In this paper we consider a transmission system based on MC-CDMA, where signal spreading is performed entirely in the frequency domain. An extended spacetime coding technique, the Double Alamouti, is evaluated considering a MIMO channel. This assessment is made against standard Alamouti coding, for two different Tx/Rx antenna schemes (2x1 and 2x2). Numerical results, attained through system model simulations, are presented for performance evaluation under realistic scenarios considering some typical system impairments. These results show that in practical systems significant improvements can be achieved by using the Double Alamouti coding scheme.

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“…In [14], a low-complexity training-based adaptive WL receiver is discussed. WL equalization in the presence of the STBC scheme of [4] is the subject of [15]. Finally, in [16], the benefits of WL processing in frequency-selective fading channels are explored.…”

mentioning

confidence: 99%

An enhanced widely linear CDMA receiver with OQPSK modulation

Mirbagheri

Plataniotis

Pasupathy

2006

IEEE Trans. Commun.

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Abstract-This paper studies an enhanced widely linear (WL) receiver for direct-sequence code-division multiple-access (DS-CDMA) systems that employ aperiodic spreading sequences with offset quadrature phase-shift keying (OQPSK) modulation. The modulation scheme generates improper complex multiple-access interference (MAI) and necessitates the use of WL receivers. Focus is on bandlimited pulse shapes and the inherent cyclostationarity (CS) of the uncoded received signal. The enhanced WL receiver replaces the conventional chip-matched filter with new filters that exploit the CS of the received signal through frequency shifting. The proposed WL receiver is shown to outperform the classical strictly linear (SL) receiver when the interfering users are (quasi-)synchronous with respect to the user of interest. High-powered interfering users, that may exist to support high data rates, increase the performance improvement delivered by the WL receiver. Moreover, it is shown that MAI can become proper, either identically or asymptotically, when users are asynchronous and equally powered. This is despite the fact that individual interfering signals are improper. Numerical results demonstrate that the WL receiver can outperform the SL receiver by 1-3 dB under the examined scenarios with current CDMA standards settings. In asynchronous or quasi-synchronous transmission modes, performance gain of the WL receiver degrades unless the number of high-powered active users remains small. An example for implementation of the WL receiver is proposed and compared with that of the SL receiver when minimum-shift keying modulation, a special case of OQPSK, is used. The implementation is based on a fractionally spaced equalizer whose taps are updated by an adaptive algorithm. It is shown that the proposed structure is capable of delivering the maximum signal-to-noise ratio predicted by theory.Index Terms-Bandlimited pulses, code-division multiple-access (CDMA), cyclostationarity (CS), fractionally spaced equalizer (FSE), improper noise, linear/conjugate-linear (L/CL) filtering, minimum-shift keying (MSK), offset quadrature phase-shift keying (OQPSK), widely linear (WL) receiver.

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Widely linear equalization for space-time block-coded transmission over fading ISI channels

Cited by 10 publications

References 15 publications

Multi-user time-reversal STC-GFDMA for future wireless networks

Multi-user time-reversal STC-GFDMA for future wireless networks

Performance of extended space-time coding techniques for MIMO MC-CDMA systems

An enhanced widely linear CDMA receiver with OQPSK modulation

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