A constrained minimum mean square error code tracking loop for synchronous DS-CDMA systems

A constrained minimum mean square error code tracking loop (CMMSE-CTL) is proposed in this paper for synchronous direct sequence code division multiple access (DS-CDMA) systems in a multiuser environment. By introducing assistant weighted despreading signals into the local reference signals of the l...

Full description

Saved in:
Bibliographic Details
Published in:International journal of electronics and communications 2010-06, Vol.64 (6), p.558-569
Main Authors: Wu, Y.T., Leung, S.H., Wong, W.K., Zhu, Y.S.
Format: Article
Language:English
Subjects:
Code tracking
Constraints
Delay lock loop
DS-CDMA
Errors
Least mean squares algorithm
Mean square values
Multiple access interference (MAI)
Reference signals
Synchronization
Synchronous
Tracking
Tracking errors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A constrained minimum mean square error code tracking loop (CMMSE-CTL) is proposed in this paper for synchronous direct sequence code division multiple access (DS-CDMA) systems in a multiuser environment. By introducing assistant weighted despreading signals into the local reference signals of the loop, we exploit the resultant extra degrees of freedom to improve the tracking performance under multiuser environment. The derived mean square tracking error is taken as the cost function and minimized with respect to the weight parameters, under the constraints which ensure an odd-symmetric bias-free S -curve with enhanced tracking range. Simulations based on Gold codes compare the S -curve, root-mean-square (rms) tracking error, mean-time-to-lose-lock (MTLL) performance of CMMSE-CTL and the traditional modified code tracking loop (T-MCTL). It is shown that CMMSE-CTL outperforms T-MCTL greatly in that it provides unbiased stable code tracking with reduced mean square tracking error, an enhanced tracking range, and near–far resistance.
ISSN:1434-8411
1618-0399
DOI:10.1016/j.aeue.2009.03.011