Precoding for the sparsely spread MC-CDMA downlink with discrete-alphabet inputs

Min Li, Chunshan Liu, Stephen V. Hanly

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Sparse signatures have been proposed for the code-division multiple-access (CDMA) uplink to reduce multiuser detection complexity, but they have not yet been fully exploited for its downlink counterpart. In this paper, we propose multicarrier CDMA (MC-CDMA) downlink communication whereby regular sparse signatures are deployed in the frequency domain. Taking the symbol detection point of view, we formulate a problem appropriate for the downlink with discrete alphabets as inputs. The solution to the problem provides a power-efficient precoding algorithm for the base station (BS), subject to minimum symbol error probability (SEP) requirements at the mobile stations (MSs). In the algorithm, signature sparsity is shown to be crucial for reducing precoding complexity. Numerical results confirm system-load-dependent power reduction gain from the proposed precoding over the zero-forcing (ZF) precoding and the regularized ZF (RZF) precoding with optimized regularization parameter under the same SEP targets. For a fixed system load, it is also demonstrated that sparse MC-CDMA with a proper choice of sparsity level attains almost the same power efficiency and link throughput as that of dense MC-CDMA yet with reduced precoding complexity due to the sparse signatures.
LanguageEnglish
Pages1116-1129
Number of pages14
JournalIEEE Transactions on Vehicular Technology
Volume66
Issue number2
DOIs
Publication statusPublished - 2017

Fingerprint

Multicarrier
Precoding
Code Division multiple Access
Code division multiple access
Signature
Symbol Error Probability
Zero-forcing
Sparsity
Multiuser detection
Base stations
Multiuser Detection
Throughput
Regularization Parameter
Uplink
Frequency Domain
Communication
Numerical Results
Target
Dependent
Requirements

Keywords

  • code-division multiple access (CDMA)
  • discrete alphabets
  • multicarrier CDMA (MC-CDMA)
  • power efficiency
  • precoding
  • sparse signature
  • symbol error probability (SEP)

Cite this

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title = "Precoding for the sparsely spread MC-CDMA downlink with discrete-alphabet inputs",
abstract = "Sparse signatures have been proposed for the code-division multiple-access (CDMA) uplink to reduce multiuser detection complexity, but they have not yet been fully exploited for its downlink counterpart. In this paper, we propose multicarrier CDMA (MC-CDMA) downlink communication whereby regular sparse signatures are deployed in the frequency domain. Taking the symbol detection point of view, we formulate a problem appropriate for the downlink with discrete alphabets as inputs. The solution to the problem provides a power-efficient precoding algorithm for the base station (BS), subject to minimum symbol error probability (SEP) requirements at the mobile stations (MSs). In the algorithm, signature sparsity is shown to be crucial for reducing precoding complexity. Numerical results confirm system-load-dependent power reduction gain from the proposed precoding over the zero-forcing (ZF) precoding and the regularized ZF (RZF) precoding with optimized regularization parameter under the same SEP targets. For a fixed system load, it is also demonstrated that sparse MC-CDMA with a proper choice of sparsity level attains almost the same power efficiency and link throughput as that of dense MC-CDMA yet with reduced precoding complexity due to the sparse signatures.",
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Precoding for the sparsely spread MC-CDMA downlink with discrete-alphabet inputs. / Li, Min; Liu, Chunshan; Hanly, Stephen V.

In: IEEE Transactions on Vehicular Technology, Vol. 66, No. 2, 2017, p. 1116-1129.

Research output: Contribution to journalArticleResearchpeer-review

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