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Joint timing and channel estimation for bandlimited long-code-based MC-DS-CDMA: A low-complexity near-optimal algorithm and the CRLB

Joint timing and channel estimation for bandlimited long-code-based MC-DS-CDMA: A low-complexity near-optimal algorithm and the CRLB
Joint timing and channel estimation for bandlimited long-code-based MC-DS-CDMA: A low-complexity near-optimal algorithm and the CRLB
Abstract—Joint Timing and Channel Estimation (JTCE) for band limited long-code-aided Multi-Carrier Direct-Sequence Code Division Multiple Access (MC-DS-CDMA) systems is investigated. We establish the optimal multiuser timing and channel estimates for the uplink MC-DS-CDMA receiver by minimizing a weighted least squares cost function with respect to K independent parameters, where K is the number of active users. A guided random search procedure known as Repeated Weighted Boosting Search (RWBS) is invoked for numerically solving this challenging multivariate optimization problem, and thereby for producing near-optimal timing and channel estimates. The Cram´ r-RaoLower Bound (CRLB) for the JTCE problem of interest is derived to benchmark the performance of the proposed RWBS based estimator. Quantitatively, for the scenario of K = 10 users, Eb /N0 ? 3 dB where Eb is the energy per bit and N0 the single-sided noise power spectral density, and for a near-far ratio of 10 dB, the RWBS based estimator using an observation window of 20 symbols is shown to approach the CRLB at a complexity 10 orders of magnitude lower in comparison to its full maximum likelihood search based counterpart. The proposed algorithm does not require the transmission of known pilots, yet it is capable of handling time-variant channel states.
1998-2011
Wang, Shuai
f2fa510e-d1de-415f-84e4-0f143946243a
Chen, Sheng
9310a111-f79a-48b8-98c7-383ca93cbb80
Wang, Aihua
5a3bdd79-ac01-49d6-ad40-d69bf1536e89
An, Jianping
a1f62ccd-2574-4fa5-be1c-22a2b35c6cf4
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Wang, Shuai
f2fa510e-d1de-415f-84e4-0f143946243a
Chen, Sheng
9310a111-f79a-48b8-98c7-383ca93cbb80
Wang, Aihua
5a3bdd79-ac01-49d6-ad40-d69bf1536e89
An, Jianping
a1f62ccd-2574-4fa5-be1c-22a2b35c6cf4
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1

Wang, Shuai, Chen, Sheng, Wang, Aihua, An, Jianping and Hanzo, Lajos (2013) Joint timing and channel estimation for bandlimited long-code-based MC-DS-CDMA: A low-complexity near-optimal algorithm and the CRLB. IEEE Transactions on Communications, 61 (5), 1998-2011.

Record type: Article

Abstract

Abstract—Joint Timing and Channel Estimation (JTCE) for band limited long-code-aided Multi-Carrier Direct-Sequence Code Division Multiple Access (MC-DS-CDMA) systems is investigated. We establish the optimal multiuser timing and channel estimates for the uplink MC-DS-CDMA receiver by minimizing a weighted least squares cost function with respect to K independent parameters, where K is the number of active users. A guided random search procedure known as Repeated Weighted Boosting Search (RWBS) is invoked for numerically solving this challenging multivariate optimization problem, and thereby for producing near-optimal timing and channel estimates. The Cram´ r-RaoLower Bound (CRLB) for the JTCE problem of interest is derived to benchmark the performance of the proposed RWBS based estimator. Quantitatively, for the scenario of K = 10 users, Eb /N0 ? 3 dB where Eb is the energy per bit and N0 the single-sided noise power spectral density, and for a near-far ratio of 10 dB, the RWBS based estimator using an observation window of 20 symbols is shown to approach the CRLB at a complexity 10 orders of magnitude lower in comparison to its full maximum likelihood search based counterpart. The proposed algorithm does not require the transmission of known pilots, yet it is capable of handling time-variant channel states.

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Published date: May 2013
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 348806
URI: http://eprints.soton.ac.uk/id/eprint/348806
PURE UUID: 861795f1-bbc7-4bd5-ac92-324063676fa8
ORCID for Lajos Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

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Date deposited: 19 Feb 2013 15:38
Last modified: 07 Aug 2019 00:53

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