Reception device and reception method
View Patent ↗At noise component addition section 105 , a noise equivalent value equivalent in size to noise component is calculated using a constant which is dependent on a difference of spreading factors between a common pilot channel and packet channels, and at correlation matrix and correlation vector calculation section 106 , the noise equivalent value is added to diagonal elements of an autocorrelation matrix. At weight calculation section 107 , an optimal weight is calculated using the autocorrelation matrix whose diagonal elements have been added the noise equivalent value, and at adaptive equalization section 108 , equalization of reception signal is carried out. Thereby, noise enhancement produced in the packet channels after the equalization due to the difference between the spreading factor of the common pilot channel and the spreading factor of the packet channels can be reduced.
1. A reception apparatus for receiving a signal wherein a common pilot channel signal spread with a spreading code of a predetermined spreading factor and packet channel signals spread with a spreading code of a smaller spreading factor than the predetermined spreading factor are code-multiplexed, the reception apparatus comprising:
a despread section that despreads the received signal with the spreading code for the common pilot channel signal;
a noise equivalent value calculation section that calculates a value that is equivalent to a noise component in size using an input signal vector indicating a despreading result of the despread section and a constant which is dependent on a difference between the spreading factor of the common pilot channel signal and the spreading factor of the packet channel signals;
a correlation matrix and correlation vector calculation section that calculates an autocorrelation matrix of the input signal vector and a cross correlation vector between the input signal vector and a desired signal vector using the value equivalent to the noise component in size calculated by the noise equivalent value calculation section;
a weight calculation section that calculates a weight used for an equalization from the autocorrelation matrix and the cross correlation vector calculated by the correlation matrix and correlation vector calculator; and
an adaptive equalization section that equalizes waveform distortions of the received signal using the weight calculated by the weight calculation section.
2. The reception apparatus according to claim 1 , wherein the correlation matrix and correlation vector calculation section adds the noise equivalent value calculated by the noise equivalent value calculation section to diagonal elements of the autocorrelation matrix.
3. The reception apparatus according to claim 1 , further comprising:
a minimal component removing section that removes components of the input signal vector below the noise equivalent value calculated by the noise equivalent value calculation section, wherein the correlation matrix and correlation vector calculation section that calculates the autocorrelation matrix and the cross-correlation vector using the input signal vector from which predetermined components have been removed by the minimal component removing section.
4. The reception apparatus according to claim 1 , wherein the noise equivalent value calculation section multiplies a maximum value of the input signal vector by the constant which is dependent on the difference between the spreading factor of the common pilot channel signal and the spreading factor of the packet channel signals.
5. The reception apparatus according to claim 1 , further comprising:
an inter-cell interference ratio calculation section that calculates a ratio of a subject cell interference component to an other-cell interference component using a time average value of the input signal vector, wherein the noise equivalent value calculation section multiplies the ratio calculated by the inter-cell interference ratio calculation section by the constant which is dependent on the difference between the spreading factor of the common pilot channel signal and the spreading factor of the packet channel signals.
6. A reception method for receiving a signal wherein a common pilot channel signal spread with a spreading code of a given spreading factor and packet channel signals spread with a spreading code of a spreading factor smaller than the given spreading factor are code-multiplexed, the reception method comprising:
a despreading step for despreading the received signal with the spreading code for the common pilot channel signal;
a noise equivalent value calculation calculating step for calculating a value equivalent in size to a noise component using an input signal vector indicating a despreading result of the despreading step and a constant which is dependent on a difference between the spreading factor of the common pilot channel signal and the spreading factor of the packet channel signals;
a correlation matrix and correlation vector calculation step for calculating an autocorrelation matrix of the input signal vector and a cross-correlation vector between the input signal vector and a desired signal vector using the value equivalent in size to the noise component calculated by the noise equivalent value calculation step;
a weight calculation step for calculating a weight used for an equalization from the autocorrelation matrix and the cross-correlation vector calculated by the correlation matrix and correlation vector calculation step; and
an adaptive equalization step for equalizing waveform distortions of the received signal using the weight calculated by the weight calculation step.