Asynchronous CDMA under single-carrier block transmissionarchitectures and signal models

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Single-carrier (SC) block transmission with frequency-domain equalization (FDE) is an efficient scheme that avoids complex time-domain equalization in multipath channels. There are also several systems that are proposed that apply SC-FDE in code-division multiple access (CDMA). However, the present CDMA systems with FDE may not be suitable for asynchronous users for lack of a signal model that can suitably express the despread signal in the frequency domain. In this paper, we first propose circularly sliding (CS) despreading that can attain preliminary separation of interference among asynchronous users. Then, we derive a signal model that represents spreading, channel effect, and despreading as a series of circular convolutions. This signal model helps to derive a new FD minimum mean-square error (MMSE) equalization algorithm for SC block transmission asynchronous CDMA. We further extend the signal model by including equalization as another circular convolution. The extended signal model indicates several equivalent architectures of the receiver. For these architectures, despreading and equalization can be implemented in either the time or frequency domain, and the order is exchangeable. Based on the proposed signal model, we also derive a RAKE combiner that can be implemented in the frequency domain. Our architectures and signal model can be applied for further development of multiuser-detection algorithms.

Original languageEnglish
Article number5282553
Pages (from-to)980-986
Number of pages7
JournalIEEE Transactions on Vehicular Technology
Volume59
Issue number2
DOIs
Publication statusPublished - 2010 Feb 1

Fingerprint

Code Division multiple Access
Code division multiple access
Equalization
Frequency-domain Equalization
Frequency Domain
Convolution
Model
Time Domain
Multiuser detection
Multipath Channels
Multipath propagation
Multiuser Detection
Minimum Mean Square Error
Mean square error
Receiver
Express
Interference
Series
Architecture

All Science Journal Classification (ASJC) codes

  • Automotive Engineering
  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Applied Mathematics

Cite this

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Asynchronous CDMA under single-carrier block transmissionarchitectures and signal models. / Chang, Ming Xian.

In: IEEE Transactions on Vehicular Technology, Vol. 59, No. 2, 5282553, 01.02.2010, p. 980-986.

Research output: Contribution to journalArticle

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