On Interference in Uplink SDMA SC-FDE system

Siddiqui, Fariha; Danilo-Lemoine, F.; Falconer, D.D.

doi:10.1109/cnsr.2007.45

Cited by 6 publications

(7 citation statements)

References 13 publications

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“…Two orthogonal training schemes, namely, Time Multiplexed Training (TMT) and Frequency Multiplexed Training (TMT), have been used in [18] to estimate the channel of IFDMA for uplink SDMA. It is shown in [18] that as long as the orthogonality of the training sequence is maintained, either using time or frequency multiplexing scheme does not bring impact in the performance in time-varying channel.…”

Section: A Training Sequencementioning

confidence: 99%

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On combining SDMA and B-IFDMA: Multi-user detection and channel estimation

Amah

Frank

Klein

2010

2010 International ITG Workshop on Smart Antennas (WSA)

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In this paper, we combine two different multiple access, namely, Space Division Multiple Access (SDMA) and Block-Interleaved Division Multiple Access (B-IFDMA), for uplink transmission, and we name the combined multiple access SD/B-IFDMA. Since SDMA suffers from multiple access interference (MAI) and B-IFDMA from intersymbol interference (ISI), a multi-user detector that can counteract both MAI and ISI is needed for SD/B-IFDMA. We propose three low complexity linear multi-user detectors for SD/B-IFDMA, namely, Zero Forcing (ZF), Minimum Mean Square Error (MMSE) and Non-Iterative Constrained Least Squares (NICLS). The NICLS is a heuristic multi-user detector that tries to improve the performance of ZF without the necessity of having to estimate the noise variance. Additionally, we also address the channel estimation procedure for SD/B-IFDMA by applying orthogonal time multiplexing training and using Chu sequence as the training sequence. Two estimators are considered for channel estimation for SD/B-IFDMA, namely, frequency domain Least Squares (LS) and time domain low complexity Maximum Likelihood (lcML). From bit error performance, it is shown that the MMSE multiuser detector performs best followed by NICLS and ZF. For performance assessment of the channel estimators, ZF multiuser detection is used. It is shown that the lcML outperforms LS with the penalty of having higher computational complexity.Index Terms-hybrid multiple access; multi-carrier and multiuser MIMO; multi-user detection; channel estimation.

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Section: A Training Sequencementioning

confidence: 99%

“…It is shown in [18] that as long as the orthogonality of the training sequence is maintained, either using time or frequency multiplexing scheme does not bring impact in the performance in time-varying channel.…”

Section: A Training Sequencementioning

confidence: 99%

On combining SDMA and B-IFDMA: Multi-user detection and channel estimation

Amah

Frank

Klein

2010

2010 International ITG Workshop on Smart Antennas (WSA)

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“…In the latter case, users' pilots interfere with one another, and the receiver's channel estimates may suffer from residual interference. Orthogonal pilots were compared with non-orthogonal pilots in [6] and for fixed pilot overhead, were found superior in performance and simplicity. In this work, in order to keep pilot overhead reasonable, we allow the pilots of the OCIs to overlap with the pilots of the ICUs, while ICUs have non-overlapping (orthogonal) pilots.…”

Section: Introductionmentioning

confidence: 99%

“…Pilot Aided channel estimation followed by a 2x1D Wiener interpolation [5] is usually employed. In SC-FDE, these pilots could be multiplexed in either time or in frequency [6], [7]. Uplink pilot signals from different users may be transmitted orthogonally or nonorthogonally.…”

Section: Introductionmentioning

confidence: 99%

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PIC Assisted IBDFE Based Iterative Spatial Channel Estimation with Intra and Inter-Cell Interference in SC-FDE System

Siddiqui

Danilo-Lemoine

Falconer

2007

2007 IEEE 66th Vehicular Technology Conference

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In this paper, the issue of channel estimation in Single Carrier Frequency Domain Equalization (SC-FDE) 1 uplink Space Division Multiple Access (SDMA) systems in the presence of intra and inter-cell interference is addressed. It is shown that in such an interference-prone system, a combination of orthogonal pilots, spatial processing and Iterative Channel Estimation (ICE) is effective. Adaptive Iterative Block Soft Decision based Feedback Equalizer (IBDFE) with Parallel Interference Cancellation (PIC) assisted Decision FeedbackIterative Channel Estimation is employed. It is shown that such a combination is a promising way to suppress uplink inter-user interference.

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