Cell searcher and cell searching method
First Claim
1. A cell search apparatus, comprising:
- a first correlator that performs a correlation calculation of a first synchronization channel;
a peak detector that detects a first peak timing based on a result of the correlation calculation in said first correlator;
a second correlator that performs the correlation calculation of a second synchronization channel on a predetermined time interval;
a second synchronization channel identifier that compares results of the correlation calculation in said second correlator at a plurality of timings and identifies the second synchronization channel from the timings that give largest correlation calculation results; and
a timing controller that gives instruction to said second synchronization channel identifier on the plurality of timings to perform the correlation calculation.
1 Assignment
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Accused Products
Abstract
Peak detector 104 detects the first peak timing where the correlation value of the first synchronization channel is the greatest. SSCH identifier 108 identifies the second synchronization channels by adding the correlation values of the second synchronization channels at a number of timings, and detects the timing where the sum of the correlation values of the identified second synchronization channels is the largest as a second peak timing. Based on the first and second peak timings, timing controller 105 instructs SSCH identifier 108 on the timing to perform correlation calculation. Likewise, based on the first and second peak timings, frequency corrector 110 calculates the error in a frame time measured by a base station, and converts this into a frequency difference, and changes the frequency of an oscillator in RF receiver 102 in such a way that corrects the frequency difference. By this means second synchronization channels and mid-ambles are accurately identified even when a base station gives a different measurement of a frame time.
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Citations
8 Claims
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1. A cell search apparatus, comprising:
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a first correlator that performs a correlation calculation of a first synchronization channel;
a peak detector that detects a first peak timing based on a result of the correlation calculation in said first correlator;
a second correlator that performs the correlation calculation of a second synchronization channel on a predetermined time interval;
a second synchronization channel identifier that compares results of the correlation calculation in said second correlator at a plurality of timings and identifies the second synchronization channel from the timings that give largest correlation calculation results; and
a timing controller that gives instruction to said second synchronization channel identifier on the plurality of timings to perform the correlation calculation. - View Dependent Claims (2, 3, 4, 5)
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6. A wireless communication terminal apparatus comprising a cell search apparatus, said cell search apparatus comprising:
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a first correlator that performs a correlation calculation of a first synchronization channel;
a peak detector that detects a first peak timing based on a result of the correlation calculation in said first correlator;
a second correlator that performs the correlation calculation of a second synchronization channel on a predetermined time interval;
a second synchronization channel identifier that compares results of the correlation calculation in said second correlator at a plurality of timings and identifies the second synchronization channel from the timings that give largest correlation calculation results; and
a timing controller that gives instruction to said second synchronization channel identifier on the plurality of timings to perform the correlation calculation.
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7. A cell search method comprising:
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a first step, wherein a correlation calculation of a first synchronization channel is performed so as to detect a first peak timing that gives a largest correlation value as a slot timing;
a second step, wherein correlation calculations of all second synchronization channels are performed and a code group assigned to a cell where an apparatus implementing the method lies is identified, so as to detect a timing of a frame top; and
a third step, wherein the correlation calculation of a mid-amble belonging to the identified code group is performed, so as to identify the mid-amble and a scrambling code assigned to the cell where the apparatus lies, wherein, in the second step, results of the correlation calculations at a plurality of timings are compared so as to identify the second synchronization channels from those corresponding to the timings that give largest correlation calculation results.
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8. A cell search method, wherein the third step is performed such that a difference of a frame time relative to the frame time measured in a base station apparatus of a communication partner is calculated and converted to a frequency difference, and an oscillator frequency in such a way that said frequency difference is corrected.
Specification