Method and apparatus for signal acquisition and power control

• US 6,169,731 B1
• Filed: 03/10/1998
• Issued: 01/02/2001
• Est. Priority Date: 03/10/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Garg, Sanjeev, Stewart, Kenneth A.
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): TON, ANTHONY T
• Application Number:
  US09/037,676
• Time in Patent Office: 1,029 Days
• Field of Search: 370/332, 370/335, 370/252, 370/337, 370/465, 370/342, 370/441, 370/442, 370/320, 370/331, 370/333, 370/334, 375/130, 375/139, 375/225, 375/140, 455/277.2, 455/115, 455/442, 455/69, 455/516, 455/517, 455/524, 455/525
• US Class Current: 370/332
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A call setup process (200) has a fast and robust preamble signal acquisition and acknowledgement procedure (400). The procedure (400) is a multistage search technique for first identifying with high probability the preamble signal and for verifying signal acquisition. The procedure (400) further includes power control (408/426/428) and rate determination (430) capability for enhanced call setup processing.

Claims

1. A method of controlling a transmit power of a remote communication unit operating in a wireless communication system, the wireless communication system including at least one base communication station, the method comprising:

transmitting from the remote communication unit a preamble message;

receiving at the base communication station the preamble message;

evaluating the content of the received preamble message and generating a quality metric, wherein the quality metric comprises one of a group consisting of a search statistic and a bit error rate; and

adjusting the transmit power of the remote communication unit based upon the quality metric.

2. The method of claim 1, wherein the preamble message comprises a frame of data, and the step of evaluating the content of the preamble message comprises comparing a received frame content with an anticipated frame content.

3. The method of claim 2, wherein the frame of data includes a frame type, and wherein the step of evaluating the content of the preamble message further comprises determining the frame type.

4. The method of claim 1, wherein the wireless communication system comprises a communication system in accordance with one of a group consisting of:

a code division multiple access communication system, a time division multiple access communication system, an analog cellular communication system.

5. A method for processing a communication request in a communication system comprising:

receiving at a base station a communication request signal from a communication unit operating in the communication system;

searching the communication request signal for multipath components;

verifying the existence of the multipath components;

recovering information from the multipath components;

comparing the recovered information to predetermined communication request information; and

sending an acknowledgment signal from the base station to the communication unit when the recovered information corresponds to the predetermined communication request information with a predetermined certainty.

6. The method of claim 5, wherein the step of searching the communication request signal for multipath components comprises generating a search statistic corresponding to each of a plurality of spaced delays.

7. The method of claim 6, wherein the step of generating a search statistic comprises integrating, over a number of Walsh symbols, the energy of a zeroth Fast Hadamard Transform output despread at a pseudonoise offset associated with each of the spaced delays.

8. The method of claim 7, wherein the number of Walsh symbols is the range of 2 and 5 Walsh symbols.

9. The method of claim 6, wherein the step of generating a search statistic comprises generating over a specific period the energy of a pilot signal associated with the communication request signal.

10. The method of claim 9, wherein the pilot signal comprises a prior known sequence.

11. The method of claim 6, comprising the step of ranking the plurality of spaced delays according to a value of the search statistic.

12. The method of claim 6, wherein the step of receiving at a base station a communication request signal comprises receiving at a pair of antennas at the base station a communication request signal.

13. The method of claim 12, wherein the step of generating a statistic corresponding to each of a plurality of spaced delays comprises generating a statistic corresponding to each of a plurality of delays at each of the pair of antennas.

14. The method of claim 13, wherein the step of generating a statistic comprises integrating, over a number of Walsh symbols, the energy of a zeroth Fast Hadamard Transform output despread at a pseudonoise offset associated with each of the spaced delays.

15. The method of claim 14, comprising the step of ranking the plurality of spaced delays according to a value of the search statistic.

16. The method of claim 15, wherein the step of ranking the plurality of spaced delays comprises summing, for corresponding pseudonoise offsets, search statistics for spaced delays at each of the pair of antennas.