초록 ▼

Users or subscribers of a spread spectrum synchronous communications system provide signals to the central station or base unit of that system, and receive signals therefrom. Proper synchronization among those users (and their signals) is needed to ensure proper operation of the system. To ensure pr

Users or subscribers of a spread spectrum synchronous communications system provide signals to the central station or base unit of that system, and receive signals therefrom. Proper synchronization among those users (and their signals) is needed to ensure proper operation of the system. To ensure proper synchronization among those users, the signal produced by each user is checked for presence and amount of any offset error. This is accomplished by using three despreaders for the signal for each user. For one such user, each such despreader for that user receives the spreading code for that user. However, the spreading code as received by any one such despreader is time-delayed with respect to the spreading code as received by the other two despreaders. Each such despreader receives the spreading code with a different amount of delay imposed on that spreading code. The outputs of the three despreaders are digitally combined (e.g. compared), or compared, to produce the offset estimate for that user. To reduce noise effects, the offset estimate is averaged over a predetermined time duration; alternatively, such averaging can be performed on the outputs of the despreaders, or at some intermediate processing step. The offset estimate is sent to the user, to be used to correct synchronization of that user. Offset estimates that are too small to be useful are squelched and are not so sent to the user, to reduce channel usage and thereby save bandwidth.

대표청구항 ▼

[ What is claimed is:] [1.]1. Apparatus for determining an offset of a spread spectrum signal spread with a pseudonoise code, comprising:a pseudonoise code generator for generating the pseudonoise code;delay means, receiving the pseudonoise code from said pseudonoise code generator, for generating a

[ What is claimed is:] [1.]1. Apparatus for determining an offset of a spread spectrum signal spread with a pseudonoise code, comprising:a pseudonoise code generator for generating the pseudonoise code;delay means, receiving the pseudonoise code from said pseudonoise code generator, for generating a first plurality of delayed pseudonoise codes each delayed by a different amount;a first despreading means receiving the spread spectrum signal and receiving the pseudonoise code from said pseudonoise code generator, for producing a first despread signal;a first plurality of despreading means, each of said first plurality of despreading means receiving the spread spectrum signal and receiving a respective one of said first plurality of delayed pseudonoise codes for producing a first plurality of despread signals; anda processor, receiving the first despread signal and the first plurality of despread signals, for combining the despread signals to produce an offset signal.