Propagation delay estimation in asynchronous direct-sequence code-division multiple access systems
1996 (English)In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 44, no 1, 84-93 p.Article in journal (Refereed) Published
In an asynchronous direct-sequence code-division multiple access CDS-CDMA) communication system, the parameter estimation problem, i.e., estimating the propagation delay, attenuation and phase shift of each user's transmitted signal, may be complicated by the so-called near-far problem. The near-far problem occurs when the amplitudes of the users' received signals are very dissimilar, as the case might be in many important applications, In particular, the standard method for estimating the propagation delays will fail in a near-far situation, Several new estimators, the maximum likelihood, an approximative maximum likelihood and a subspace-based estimator, are therefore proposed and are shown to be robust against the near-far problem, No knowledge of the transmitted bits is assumed, and the proposed estimators can thus be used for both acquisition and tracking. In addition, the Cramer-Rao bound is derived for the parameter estimation problem.
Place, publisher, year, edition, pages
1996. Vol. 44, no 1, 84-93 p.
Attenuation, Code standards, Delay estimation, Detectors, Direct-sequence code-division multiple access, Multiaccess communication, Parameter estimation, Phase estimation, Propagation delay, Sensor systems
IdentifiersURN: urn:nbn:se:kth:diva-60032DOI: 10.1109/26.476100ISI: A1996TQ87300015OAI: oai:DiVA.org:kth-60032DiVA: diva2:477137
NR 201408052012-01-122012-01-122012-02-14Bibliographically approved