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US 2001/0043644 A1Published application
Method of despreading a spread spectrum signal
AssigneeKoninklijke Philips Electronics N.V.
InventorsSaul R. Dooley, Andrew T. Yule
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AssigneeKoninklijke Philips Electronics N.V.
InventorsSaul R. Dooley, Andrew T. Yule
Estimating the term…
A method of despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message is disclosed. The method comprises the steps of providing data message information relating to the timing of an epoch of at least one data bit; and performing a correlation of the target signal and a replica signal containing corresponding PRN code sequences using the data message information to minimise degradation of the correlation caused by variations in the PRN code sequences in the target signal attributable to modulation by the data message. The correlation may be timed so as to substantially avoid continuous correlation over an epoch of a data bit. Alternatively, the data message information may further comprise bit information wherein the correlation is modified as a function of the data message information. In particular, where data bit modulation of the PRN code sequences in the target signal is the same as or equivalent to exclusive-or modulation, the polarity of PRN code sequences in the replica signal may be selectively reversed.
A method of despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message comprising the steps of:
A method according to any of the preceding claims wherein pseudorandom noise (PRN) code sequences of the target spread spectrum signal are modulated by a data message, at least part of which is cyclically repeated, and wherein at least some of the data bit information is predicted based on a previous data message.
A method according to any of the preceding claims wherein the target signal is a GPS signal and is received by a mobile unit;
A method of despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message as hereinbefore described with reference to the accompanying figures.
A mobile unit comprising a receiver for receiving a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message, and a signal containing data message information relating to the timing of an epoch of at least one data bit;
A mobile unit according to claim 37 wherein the data message information relating to the timing of an epoch of at least one data bit of the target signal is derived from the timing of an epoch of at least one data bit of the reference signal.
A mobile unit for despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message as hereinbefore described with reference to the accompanying figures.
A base station comprising a receiver for receiving from a mobile unit a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message received by the mobile unit, means for providing data message information;
A base station for despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message as hereinbefore described with reference to the accompanying figures.
A combination of a mobile unit and a base station for despreading a target spread spectrum signal containing pseudorandom noise (PRN) code sequences modulated by a data message as hereinbefore described with reference to the accompanying figures.
Dependencies are inferred from the claim text.