Method and system for determining the time of arrival of a direct radio signal

• US 20070135054A1
• Filed: 12/13/2005
• Published: 06/14/2007
• Est. Priority Date: 12/13/2005
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Belcea, John
• Granted Patent: US 7,489,904 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0221 Receivers
• CPC Class Codes: H04B 17/364 Delay profiles

Abstract

A method and system for determining the time of arrival of a direct radio signal. The system including a receiver (210) for receiving a plurality of signals, wherein each of the plurality of received signals has an associated time of arrival. The system further including a processor (215) adapted to compute a impulse response function of a received signal; decompose an impulse response function comprising the time of arrival for each of the plurality of received signals; and identify a smallest time of arrival from the decomposed impulse response function.

Claims

1. A method for determining a time of arrival of a direct radio signal within a wireless communication network comprising the steps of:

decomposing an impulse response function, wherein the impulse response function comprises a time of arrival for each of a plurality of received signals; and

identifying a smallest time of arrival from the decomposed impulse response function.

2. A method for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 1, further comprising the steps of:

identifying the time of arrival of the strongest signal;

storing the time of arrival of the strongest signal;

eliminating the impulse response of the strongest signal from the impulse response of the received signal;

repeating the identifying, storing, and eliminating steps for a predetermined number of times; and

determining the time of arrival of the direct radio signal as the smallest value of the stored time of arrivals.

3. A method for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 2, wherein the decomposing step comprises the steps of:

using quadratic interpolation to identify a time of arrival associated with a peak in the impulse response function.

4. A method for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 3, wherein the decomposing step further comprises:

setting a set V of the impulse response function; and

computing V=V−

A(t, t_i)+V₀,

wherein t_i is the time of arrival associated with the peak in the impulse response.

5. A method for determining a time of arrival of a direct radio signal within a wireless communication network comprising the steps of:

collecting a predetermined number of values of an impulse response function, with the maximum value of the function being included in the set;

normalizing the data set of collected values and store the normalized values in vector V₀;

setting a set V=V₀;

initializing a vector T with very large values as the approximated time of arrival;

running a decomposition algorithm a predetermined number of times;

replacing the largest value of vector T with the time of arrival (t₀) resulting from the decomposition algorithm;

repeating the running and replacing steps for a predetermined number of times; and

identifying the smallest value of T as the earliest time of arrival.

6. A method for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 5, wherein the vector T is initialized to infinity.

7. A method for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 5, wherein the running the decomposition algorithm step comprises the steps of:

using quadratic interpolation to find the time of arrival (t_i) associated with the peak of the impulse response function for a set V; and

computing V=V−

A(t, t_i)+V₀.

8. A system for determining a time of arrival of a direct radio signal within a wireless communication network comprising:

a receiver for receiving a plurality of signals, wherein each of the plurality of received signals has an associated time of arrival; and

a processor adapted to;

compute a impulse response function of a received signal;

decompose an impulse response function comprising the time of arrival for each of the plurality of received signals; and

identify a smallest time of arrival from the decomposed impulse response function.

9. A system for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 8, further comprising:

a memory coupled to the processor for storing the identified smallest time of arrival,

wherein the processor is further adapted to;

identify the time of arrival of the strongest signal

store the identified time of arrival of the strongest signal,

eliminate a impulse response of the strongest signal from the impulse response of the received signal;

repeat the identifying, storing, and eliminating operations for a predetermined number of times; and

determine the time of arrival of the direct radio signal as the lowest value of the stored time of arrivals.

10. A system for determining a time of arrival of a direct radio signal within a wireless communication network comprising:

a receiver for receiving a plurality of signals, wherein each of the plurality of received signals has an associated time of arrival; and

a processor adapted to;

collect a predetermined number of values of an impulse response function, with the maximum value being part of the collected set;

normalize the data set of collected values and store the normalized values in vector V₀;

set a set V=V₀;

initialize a vector T as the time of arrival;

run the decomposition algorithm;

replace the largest value of T with the time of arrival (t₀) resulting from the decomposition algorithm;

repeat the running the decomposition algorithm and replacing operations for a predetermined number of times; and

identify the smallest value of T as the earliest time of arrival.

11. A system for determining a time of arrival of a direct radio signal within a wireless communication network as claimed in claim 10, wherein the decomposition algorithm comprises:

using quadratic interpolation to find the time of arrival (t_i) associated with the peak of the impulse response function for a set V; and

computing V=V−

A(t, t_i)+V₀.