Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2000-07-28
2004-03-02
Bocure, Tesfaldet (Department: 2631)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S150000
Reexamination Certificate
active
06700924
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a spread-spectrum data transmission apparatus comprising a data receiver for receiving data organized in symbols of duration T
s
and spread by means of a spreading code having period T
c
before a transmission channel is borrowed which channel has various broadcasting paths each producing delays, which receiver comprises:
a receiving circuit called Rake circuit formed by <<L>>branches for processing data relating to a path delay,
an estimation circuit for the received symbols.
The invention also relates to a method of processing data featuring a spectrum spreading.
BACKGROUND OF THE INVENTION
Such apparatus are well known and find many applications notably in the field of portable telephones. On this subject European patent EP 0-851 600 can be consulted. This known apparatus comprises a receiver, which combines signals delayed by one symbol period or more, with the aim to diminish the influence of interference which occurs in time periods that exceed this symbol period.
SUMMARY OF THE INVENTION
The present invention also proposes to eliminate the interference which occurs in periods which exceed various times this symbol period but by utilizing other methods.
For this purpose, such a receiver is characterized in that it further includes a long-duration interference canceling circuit which covers various T
s
.
These and other aspects of the invention are apparent from and will be elucidated, by way of non-limitative example, with reference to the embodiment(s) described hereinafter.
REFERENCES:
patent: 6009098 (1999-12-01), Asamizuya
patent: 6067292 (2000-05-01), Huang et al.
patent: 6272167 (2001-08-01), Ono
patent: 6414949 (2002-07-01), Boulanger et al.
patent: 6496534 (2002-12-01), Shimizu et al.
patent: 0851600 (1998-01-01), None
patent: WO9705709 (1997-02-01), None
Park et al., “Antenna Array using a Channel Estimation Technique in a DS/CDMA System with M-ary Orthogonal Modulation,” 2000 IEEE, pp. 759-763.*
Sawahashi et al., “Experiments on Pilot Symbol-Assisted Coherent Multistage Interference Canceller for DS-CDMA Mobile Radio,” 2002, IEEE Journal on Selected Areas in Communications, vol. 2, pp 433-449.*
Su II Kim et al., “Performance improvement of RAKE receiver for Multicode DS-CDMA System with Multistage Interference Cancellation Detectors,” 1999, IEEE TENCON, pp 573-576.*
BY R. PRICE & P.E. Green, Entitled: “A CcmmunicationTechnique For Mutipath Channels” Proceedings Of Ire, vol. 46, Mar. 1958, PP. 555-570.
Bocure Tesfaldet
Koninklijke Philips Electronics , N.V.
Schmitt Michael E.
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