Method and system for providing an estimate of the signal strength of a received signal

• US 6,201,954 B1
• Filed: 03/25/1998
• Issued: 03/13/2001
• Est. Priority Date: 03/25/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Soliman, Samir S.
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US09/048,454
• Time in Patent Office: 1,084 Days
• Field of Search: 455/226.1, 455/226.2, 455/226.3, 455/226.4, 455/227, 455/524, 455/525, 455/442, 370/332
• US Class Current: 455/226.2
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 52/04 TPC

Abstract

The signal strength of a received signal in a communication system is estimated by the measured signal strength of a desired signal which is transmitted from a source device to a destination device. The energy of the desired signal and the energy of the noise are measured or computed. The measured signal strength can be computed by dividing the energy of the desired signal with the energy of the noise. The signal strength of the desired signal can be estimated as the maximum likelihood estimate of the actual signal strength α. The signal strength of the desired signal can also be estimated based on the expected value of the energy of the desired signal. The signal strength of the desired signal can further be estimated based on the expected value of the energy of the desired signal and accounting for a predetermined bias.

Claims

1. A method for providing an estimate of a received signal strength, the method comprising:

receiving a signal, the received signal comprising a desired signal;

measuring an energy of the desired signal to provide a measured energy, the measuring further comprising first integrating the desired signal over a first predetermined interval to provide an averaged energy, and second integrating the averaged energy over a second predetermined interval to provide the measured energy; and

estimating a signal strength of the desired signal in accordance with the measured energy, wherein the estimated signal strength is indicative of the received signal strength.

2. The method of claim 1 wherein the second integrating is performed non-coherently.

3. A method for providing an estimate of a received signal strength, the method comprising:

receiving a signal, the received signal comprising a desired signal;

measuring an energy of the desired signal to provide a measured energy; and

estimating a signal strength of the desired signal in accordance with the measured energy, wherein the estimated signal strength is indicative of the received signal strength, and wherein the estimating comprises computing a maximum likelihood estimate of an actual signal strength based on the measured energy, and wherein the signal strength is based on the maximum likelihood estimate.

4. The method of claim 3 wherein the computing is performed with a translation up table.

5. A signal strength estimator for providing an estimate of a signal strength of a received signal in a communication system, comprising:

a receiver for providing a received signal, the received signal comprising a desired signal;

a signal processor connected to the receiver for receiving the received signal and providing the desired signal;

an energy calculator connected to the signal processor for receiving the desired signal and providing the measured energy, the energy calculator comprising a first integrator for receiving the desired signal and integrating the desired signal over a first predetermined interval to provide an averaged energy, and a second integrator connected to the first integrator for receiving the averaged energy and integrating over a second predetermined interval to provide a measured energy; and

a signal strength estimator connected to the energy calculator for receiving the measured energy and providing an estimate of a signal strength of the desired signal based on the measured energy, wherein the signal strength is indicative of the signal strength of the received signal.

6. The signal strength estimator of claim 5 wherein the second integrator is a non-coherent integrator.

7. A signal strength estimator for providing an estimate of a signal strength of a received signal in a communication system, comprising:

a receiver for providing a received signal, the received signal comprising a desired signal;

a signal processor connected to the receiver for receiving the received signal and providing the desired signal;

an energy calculator connected to the signal processor for receiving the desired signal and providing the measured energy; and

a signal strength estimator connected to the energy calculator for receiving the measured energy and providing an estimate of a signal strength of the desired signal based on the measured energy, wherein the signal strength is indicative of the signal strength of the received signal, the signal strength estimator comprising means for computing a maximum likelihood estimate of an actual signal strength based on the measured energy, wherein the signal strength is based on the maximum likelihood estimate.

8. The signal strength estimator of claim 7 wherein the means for computing is a translation up table.

9. In a communication system capable of providing transmissions from at least one base station to at least one subscriber station, a method for measuring link signal strength, the method comprising:

transmitting a desired signal from at least one base station to a subscriber station;

receiving the desired signal at the subscriber station to provide a measured energy; and

estimating a signal strength of the received desired signal based on the measured energy, the estimating comprising computing a maximum likelihood estimate of an actual signal strength based on the measured energy, wherein the signal strength is based on the maximum likelihood estimate.

10. The method of claim 9 wherein the computing is performed with a translation up table.

11. In a communication system capable of providing soft handoff transmissions from at least one base station to at least one subscriber station, a method for selecting the soft handoff transmissions, the method comprising:

transmitting a desired signal from at least one base station to a subscriber station;

first receiving the desired signal at the subscriber station to provide a measured energy;

estimating a signal strength of the received desired signal based on the measured energy, the estimating comprising computing a maximum likelihood estimate of an actual signal strength based on the measured energy, wherein the signal strength is based on the maximum likelihood estimate;

sending the estimated signal strength of the received signal to the at least one base station; and

second receiving the estimated signal strength of the received signal,

wherein the soft handoff transmissions are selected based on the received estimated signal strength.