Method and apparatus for mobile radio velocity estimation
AssigneeMotorola, Inc.
InventorFouad C. Freiha
Life of this patent
Estimating the term…
Abstract
A mobile radio velocity estimation system (100) includes an autocorrelation block (106) that determines the autocorrelation of a received signal (104) using one lag (102). A power determination block (108) determines the power of the received signal (104) and a divider block (114) divides the autocorrelation (110) by the power (112). Using a Bessel function lookup table (116) and a multiplication by λ/τ block (118), an estimate (120) for the mobile radio's velocity can be calculated. A method for estimating the velocity of a mobile radio (500) is also discussed.
Claims9
A radio, comprising:
- a receiver for receiving a radio signal;
- and
- a velocity estimation block coupled to the receiver for estimating the velocity of the radio, the velocity estimation block including:
- an autocorrelation block coupled to the receiver for determining the
- autocorrelation of the received signal using a predetermined lag;
- a power block coupled to the receiver for determining the power of the received signal;
- and
- a Bessel lookup table coupled to the autocorrelation and power blocks for estimating the velocity of the radio;
- wherein the velocity estimation block estimates the velocity of the radio using the equation
- v
- =
- λ
-
- InverseJ
- 0
-
- (
- E
-
- [
- r
-
- (
- t
- )
-
- r
-
- (
- t
- -
- τ
- )
- ]
- E
-
- [
- r
-
- (
- t
- )
- 2
- ]
- )
- 2
-
- πτ
- ,
- where,
- E[r(t)r(t−τ)] Autocorrelation of the received signal,
- τ Lag associated with the correlation,
- E[r(t)2] Signal power,
- J0 Bessel function of order 0,
- v Velocity of the radio communication device,
- λ Wavelength of the signal;
- and
- Inverse J00 values found in the inverse Bessel function table.
A method for estimating the velocity of a radio communication device, comprising the steps of:
- receiving a signal at the radio communication device;
- computing the power of the received signal;
- computing the autocorrelation of the received signal using a single lag associated with the correlation;
- and
- using an inverse Bessel function table and the computed power and autocorrelation to provide an estimate of the velocity of the radio communication device;
- wherein the single lag and the inverse Bessel function table are stored in the radio communication device;
- and
- wherein the method is performed using a controller that uses the equation:
- v
- =
- λ
-
- InverseJ
- 0
-
- (
- E
-
- [
- r
-
- (
- t
- )
-
- r
-
- (
- t
- -
- τ
- )
- ]
- E
-
- [
- r
-
- (
- t
- )
- 2
- ]
- )
- 2
-
- πτ
- ,
- where,
- E[r(t)r(t−τ)] Autocorrelation of the received signal,
- τ Lag associated with the correlation,
- E[r(t)2] Signal power,
- J0 Bessel function of order 0,
- v Velocity of the radio communication device,
- λ Wavelength of the signal;
- and
- Inverse J00 values found in the inverse Bessel function table.
Dependencies are inferred from the claim text.