System and method for synchronizing acquisition for a code modulated communication system
AssigneeEricsson Inc.
InventorsEssam Sourour, Gregory E. Bottomley, Rajaram Ramesh
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Abstract
A system and method for a synchronizing acquisition of a transmitted signal with a local code in a code modulated communication system. The local code is comprised of a replica of the transmitted code. Samples of the transmitted code are correlated with the local code and resulting periodic output samples having indexes are compared with a threshold. Selected indexes of the samples exceeding the threshold are stored and verified for synchronization. Stored correlation indexes which exceed the threshold are combined, and a responder achieves synchronization between transmitted signal and the local code.
Claims29
A system for synchronizing acquisition of a transmitted signal with a local code in a code modulated communication system having a transmitted signal and a local code which is a replica of the code of the transmitted signal, comprising;
- a correlator for producing a correlation index reproducing a correlation index representative of the extent of correlation during each one of a plurality of search periods;
- a history register memory with a plurality of registers for a current set of correlation indexes and a plurality of registers for a previous set of correlation indexes for storing the correlation indexes produced during each of the plurality of successive search periods;
- a stored correlation index combiner for combining the stored correlation indexes from the history register memory which exceed a preselected threshold;
- and
- a responder for responding to the combined indexes to achieve synchronization between the transmitted signal and the local code.
A method for synchronizing acquisition of a transmitted signal with a local code in a code modulated communication system in which the local code is a replica of the code of the transmitted signal, comprising the steps of:
- producing a correlation index representative of the extent of correlation during each one of a plurality of search periods;
- storing the correlation indexes produced during each of the plurality of successive search periods in a history register memory with a plurality of registers for a current set of correlation indexes and a plurality of registers for a previous set of correlation indexes;
- combining via a stored correlation index combiner the stored correlation indexes from the history register memory which exceed a preselected threshold;
- and
- responding the combined indexes to achieve synchronization between the transmitted signal and the local code.
A method of acquisition for acquiring synchronizing of a received transmitted signal with a local signal in a modulated communication system, the method comprising the steps of:
- correlating first outputted samples of the received signal and the local signal;
- establishing a first search threshold;
- comparing the correlated first outputted samples to the first search threshold;
- storing a selected number of samples first correlated that exceed the first threshold in a first history register memory;
- establishing a verification threshold;
- recorrelating the samples stored in the first history register memory;
- comparing the recorrelated samples in the first history register memory to the verification threshold;
- and
- establishing synchronization for the recorrelated stored samples corresponding to the first outputted samples which exceed the verification threshold a selected number of times.
A system of acquisition for acquiring synchronizing of a received transmitted signal with a local signal in a modulated communication system, comprising:
- means for correlating first outputted samples of the received signal and the local signal;
- means for establishing a first search threshold;
- means for comparing the correlated first outputted samples to the first search threshold;
- and
- means for storing a selected number of samples first correlated that exceed the first threshold in a first history register memory.
Dependencies are inferred from the claim text.