Velocity estimation apparatus and method using level crossing rate

A velocity estimator using a level crossing rate, comprising:

• a down-sampler for down-sampling a signal received from a mobile terminal according to a predetermined down-sampling factor M;
• a power calculator for calculating power values of the down-sampled signal;
• an interpolator for interpolating the power values according to a predetermined interpolation ratio L;
• a root mean square calculator for calculating a root mean square value using an output of the interpolator, wherein the root mean square value becomes a level crossing threshold;
• a level crossing counter for counting the level crossing frequency representing how many times the output of the interpolator crosses the level crossing threshold for a predetermined time period;
• and
• a velocity calculator for calculating a velocity estimation value of the mobile terminal using the level crossing frequency.

A velocity estimation method using a level crossing rate, comprising the steps of:

• calculating power values of a signal down-sampled with a signal received from a mobile terminal;
• interpolating the power values according to a predetermined interpolation ratio;
• calculating a root mean square value using the interpolated values, wherein the root mean square value becomes a level crossing threshold;
• counting a level crossing frequency representing how many times the interpolated values cross the level crossing threshold for a predetermined time period;
• and
• calculating a velocity estimation value of the mobile terminal using the level crossing frequency.