Increasing User Capacity by Interference Avoidance and Intentional Asynchrony in CDMA Systems

Author

Hombs, Brandon ; Lehnert, James S.

Author_Institution

BAE Syst. Adv. Syst. & Technol., Merrimack

Volume

54

Issue

4

fYear

2008

fDate

4/1/2008 12:00:00 AM

Firstpage

1754

Lastpage

1760

Abstract

This correspondence examines the number of users that can be supported at a given signal-to-interference ratio in asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems. It is shown that for many chip waveforms the user capacity for asynchronous systems is larger than for optimally designed synchronous systems. The degree to which the user capacity improves by exploiting asynchrony is characterized by defining the effective dimension of the chip waveform. Finally, simulation results are shown to verify the analysis.

Keywords

code division multiple access; spread spectrum communication; DS-CDMA; asynchronous direct- sequence code-division multiple-access systems; chip waveform; interference avoidance; signal-to-interference ratio; user capacity; Analytical models; Eigenvalues and eigenfunctions; Interference; Iterative algorithms; Matched filters; Multiaccess communication; Power system modeling; Proposals; Signal analysis; Timing; Code-division multiple access (CDMA); interference avoidance; user capacity;

fLanguage

English

Journal_Title

Information Theory, IEEE Transactions on

Publisher

ieee

ISSN

0018-9448

Type

jour

DOI

10.1109/TIT.2008.917677

Filename

4475372