US 2011/0032974 A1Published application

Carrier frequency synchronization detection circuit and correlation calculator

AssigneePanasonic Corporation

InventorShingo Karino

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Abstract

A correlation calculator and carrier frequency synchronization detection circuit are provided that enable a code phase, carrier frequency, and carrier frequency phase match to be detected even if a carrier frequency is greatly displaced. A correlation value calculation section (130) has n storage elements (501 through 507) that store a spread code, n-integral-multiple first delay elements (401 through 414) that perform sequential shifting by delaying an I component baseband signal by a fixed time interval, and n-integral-multiple first multipliers (701 through 714) that respectively perform multiplication between sequentially shifted I component baseband signals and the storage elements (501 through 507). The same kind of configuration as in the case of an above I component baseband signal is also provided for a Q component baseband signal.

Claims9

Dependent claims

A carrier frequency synchronization detection circuit comprising:

a code generation section that generates a spread code for performing despreading processing in synchronization with a received signal on which spreading processing has been executed;
a mixing section that removes a carrier frequency component from a received signal;
a correlation value calculation section that calculates a correlation value between a received signal from which a carrier frequency component has been removed by said mixing section and a spread code generated by said code generation section and a plurality of correlation intermediate values of a predetermined correlation length;
a correlation value averaging section that averages correlation values output from said correlation value calculation section, on a regular basis, over a plurality of periods;
a maximum sorting section that selects a maximum correlation value from among averaged correlation values;
a code phase selection section that determines spread code sequence generation timing based on a correlation value selected by said maximum sorting section;
a correlation intermediate value monitoring section that outputs a carrier frequency correction value and carrier phase correction value from a correlation intermediate value output from said correlation value calculation section;
and
a carrier frequency generation section that outputs a carrier frequency to said mixing section based on the carrier frequency correction value and carrier phase correction value output from said correlation intermediate value monitoring section.

6 more elements

A correlation calculator for performing correlation of a spread code with a complex baseband signal composed of in-phase component and quadrature component baseband signals spread by a spread code of n chips (where n is an arbitrary natural number of 2 or above) per symbol, the correlation calculator comprising:

n storage elements that store a spread code;
n-integral-multiple first delay elements that perform sequential shifting by delaying an in-phase component baseband signal by a fixed time interval, and n-integral-multiple first multipliers that respectively perform multiplication between in-phase component baseband signals sequentially shifted by first delay elements and said storage elements;
and
n-integral-multiple second delay elements that perform sequential shifting by delaying a quadrature component baseband signal by a fixed time interval, and n-integral-multiple second multipliers that respectively perform multiplication between quadrature component baseband signals sequentially shifted by second delay elements and said storage elements, wherein:
a result of performing integration of outputs from first through (1×k)′th first multipliers among n-integral-multiple first multipliers is taken as a correlation first in-phase intermediate value, a result of performing integration of outputs from first through (2×k)′th first multipliers is taken as a correlation second in-phase intermediate value, and output as correlation m′th in-phase intermediate results is performed thereafter sequentially;
and
a result of performing integration of outputs from first through (1×k)′th second multipliers among n-integral-multiple second multipliers is taken as a correlation first quadrature intermediate value, a result of performing integration of outputs from first through (2×k)′th second multipliers is taken as a correlation second quadrature intermediate value, and output as correlation m′th quadrature intermediate results is performed thereafter sequentially.

4 more elements

Dependencies are inferred from the claim text.