Initial acquisition and frame synchronization in spread spectrum communication system
AssigneeSamsung Electronics Co., Ltd.
InventorHi-Chan Moon
Life of this patent
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Abstract
A device for rapidly performing initial acquisition and frame synchronization of a received signal for a receiver in a CDMA communication system. To this end, the base station multiplies a spreading sequence for a pilot channel by a synchronization pattern which maintains a pattern of inverting its sign in order to delineate the boundaries of the short sequence periods. A mobile station initially calculates the spreading sequence of the short period and the correlation value to perform initial acquisition, and despreads N-chip duration around a boundary of the one short spreading sequence period to detect the multiplied pattern, thereby acquiring synchronization of a data frame.
Claims10
A device for receiving a channel signal for a mobile station in a code division multiple access (CDMA) communication system which includes a first chip rate being multiple times a second chip rate, a first frame with a duration of a spreading sequence having the second chip rate and a second frame whose frame length is multiple times a length of the first frame, in order to receive a spread signal using a spreading code having the first chip rate, which inverts its sign at every other first frame duration, the device comprising:
- a despreader for despreading the spread signal with a spreading sequence having the first chip rate;
- an orthogonal demodulator for orthogonally demodulating a pilot channel signal from the despread signal;
- a decider for examining the pilot channel signal to determine whether the pilot channel signal has varied in sign, and upon detection of variation in sign of the pilot channel signal, deciding a boundary of the first frame;
- and
- a sync channel receiver for determining a boundary of the first frame for the sync channel according to an output of the decider and detecting sync bits for predetermined positions of the first frame to acquire synchronization of the second frame.
A device for receiving a channel signal for a mobile station in a code division multiple access (CDMA) communication system which includes a first chip rate being multiple times a second chip rate, a first frame with a duration of a spreading sequence having the second chip rate and a second frame whose frame length is multiple times a length of the first frame, in order to receive a spread signal using a spreading code having the first chip rate, which inverts its sign every other first frame duration, the device comprising:
- a despreader for despreading the spread signal with a spreading sequence having the first chip rate;
- an orthogonal demodulator for orthogonally demodulating a pilot channel signal from the despread signal;
- a decider for examining the pilot channel signal to determine whether the pilot channel signal has varied in sign, and upon detection of variation in sign of the pilot channel signal, deciding a boundary of the second frame;
- and
- a sync channel receiver for determining a boundary of the second frame for the sync channel according to an output of the decider to detect synchronization of the second frame.
A method for receiving a channel signal for a mobile station in a CDMA communication system which includes a first chip rate being multiple times a second chip rate, a first frame with a duration of a spreading sequence having the second chip rate and a second frame whose frame length is multiple times a length of the first frame, in order to receive a spread signal using a spreading code having the first chip rate, which inverts its sign every other first frame duration, the method comprising the steps of:
- despreading the spread signal with a spreading sequence having the first chip rate;
- orthogonally demodulating a pilot channel signal from the despread signal;
- examining the pilot channel signal to determine whether the pilot channel signal has varied in sign, and upon detection of variation in sign of the pilot channel signal, deciding a boundary of the first frame;
- and
- determining a boundary of the first frame for the sync channel according to the decision result and detecting sync bits for predetermined positions of the first frame to acquire sync of the second frame.
A method for receiving a channel signal for a mobile station in a CDMA communication system which includes a first chip rate being multiple times a second chip rate, a first frame with a duration of a spreading sequence having the second chip rate and a second frame whose frame length is multiple times a length of the first frame, in order to receive a spread signal using a spreading code having the first chip rate, which inverts its sign every other first frame duration, the method comprising the steps of:
- despreading the spread signal with a spreading sequence having the first chip rate;
- orthogonally demodulating a pilot channel signal from the despread signal;
- examining the pilot channel signal to determine whether the pilot channel signal has varied in sign, and upon detection of variation in sign of the pilot channel signal, deciding a boundary of the second frame;
- and
- determining a boundary of the second frame for the sync channel according to the decision result to detect sync of the second frame.
Dependencies are inferred from the claim text.