Spreading code estimating apparatus and spreading code estimating method
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorSatoshi Imaizumi
Life of this patent
Estimating the term…
Abstract
A preliminary selection averaging section 105 averages a small number of correlation values, a candidate code selecting section 106 selects some spreading codes, each having a high average correlation value, as candidates of a real spreading code, an actual selection averaging section 107 performs the averaging the correlation values of the respective candidate codes by use of the number of correlation values necessary for sufficiently restraining noise, and a maximum value detecting section 108 estimates a spreading code, having a maximum correlation value, as a real spreading code. Thereby, time for an initial synchronization can be reduced without decreasing the accuracy of the spreading code estimation.
Claims11
A spreading code estimating apparatus comprising:
- a correlation value computing system that computes a correlation value between a receiving signal and a replica code;
- a first averaging system that averages L correlation values for each replica code so as to compute a first correlation value;
- a preliminary selecting system that selects a replica code as a candidate based on said first correlation value,
- a second averaging system that averages N, where N>L, correlation values for each replica code selected in said preliminary selecting system so as to compute a second correlation value;
- and
- an actual selecting system that estimates a spreading code by which the receiving signal is multiplied based on said second correlation value.
A spreading code estimating method comprising:
- computing a correlation value between a receiving signal and each of all replica codes stored;
- computing a first correlation value by averaging L correlation values for each replica code;
- selecting a spreading code as a candidate based on said first correlation value;
- computing a correlation value between the receiving signal and the selected replica code;
- computing a second correlation value by averaging N, where N>L, correlation values for each selected replica code;
- and
- estimating a spreading code by which the receiving signal is multiplied based on said second correlation value.
A mobile station apparatus having a spreading code estimating apparatus, said spreading code estimating apparatus comprising:
- a correlation value computing system that computes a correlation value between a receiving signal and a replica code;
- a first averaging system that averages L correlation values for each replica code so as to compute a first correlation value;
- a preliminary selecting system that selects a replica code as a candidate based on said first correlation value;
- a second averaging system that averages N, where N>L, correlation values for each replica code selected in said preliminary selecting system so as to compute a second correlation value;
- and
- an actual selecting system that estimates a spreading code by which the receiving signal is multiplied based on said second correlation value.
A base station apparatus having a spreading code estimating apparatus, said spreading code estimating apparatus comprising:
- a correlation value computing system that computes a correlation value between a receiving signal and a replica code;
- a first averaging system that averages L correlation values for each replica code so as to compute a first correlation value;
- a preliminary selecting system that selects a replica code as a candidate based on said first correlation value;
- a second averaging system that averages N, where N>L, correlation values for each replica code selected in said preliminary selecting means so as to compute a second correlation value;
- and
- an actual selecting system that estimates a spreading code by which the receiving signal is multiplied based on said second correlation value.
Dependencies are inferred from the claim text.