Method and apparatus for performing search acquisition in a multi-carrier communication system

• US 6,466,606 B1
• Filed: 12/22/1999
• Issued: 10/15/2002
• Est. Priority Date: 12/22/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jou, Yu-Cheun
• Primary Examiner(s): CORRIELUS, JEAN B
• Application Number:
  US09/470,224
• Time in Patent Office: 1,028 Days
• Field of Search: 375/130, 375/136, 375/140, 375/142, 375/143, 375/144, 375/147, 375/148, 375/150, 375/152, 375/367, 375/366, 375/368, 375/365, 375/260, 370/342, 370/500, 370/503, 370/491, 370/515
• US Class Current: 375/130
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/70775 Multi-dwell schemes, i.e. multiple accumulation times
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70707 Efficiency-related aspects
• CPC Class Codes: H04L 5/026 using code division
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

A method and apparatus to search for a traffic channel in a multi-carrier spread spectrum communication network. In this first embodiment, all three pilot signals are transmitted with equal power from the base station. The remote station can noncoherently combine the received energy of all three-pilots on a time hypothesis. This will reduce the value of M (the noncoherent accumulation time) by a factor of three. Thus the mean acquisition time is shortened by a factor of three with the same probability of detection and false alarm as a signal carrier (1×) system, if each pilot is equivalent to a 1× pilot in power. Note that the number of operations (i.e., complexity) is the same as that for a 1× system, but the time elapsed is shortened by a factor of 3.

Claims

1. A method to reduce search time for acquiring multiple carriers, comprising:

using sequentially smaller search windows to identify a first carrier, wherein the sequentially smaller search windows is a sequence of narrowly defined search windows; and

using the smallest of the sequentially smaller search windows used to identify the first carrier is used to identify other carriers in the multiple carriers in a multi-carrier communications network.

2. The method as recited in claim 1, further comprising:

determining a quality metric for the other carriers based upon a signal quality metric determined for the first carrier.

3. The method as recited in claim 1, wherein a narrowly defined search window comprises a subset of a plurality of periodic binary (PN) sequences contained in each search window of the sequentially smaller search windows.

4. The method in accordance with claim, 1, wherein if using the smallest of the sequentially smaller search windows fails to identify a second carrier of the other carriers in the multiple carriers, using a sequentially larger search window that was used in identifying the first carrier to identify the second carrier.

5. A method to reduce search time for acquiring multiple carriers, comprising:

(a) receiving a signal associated with a first carrier;

(b) demodulating the signal to provide signal metrics;

(c) determining whether or not the signal metrics are defined within the boundaries of a search window;

(d) if the signal metrics are defined within the search window, further demodulating the signal to provide additional signal metrics, the additional signal metrics used to determine whether or not the signal is defined within the boundaries of a smaller window; and

(e) if the signal is accessible by a designated user, using the smaller window to search for other signals associated with related carriers in the multiple carrier and accessible by the designated user.

6. The method in accordance with claim 5, further comprising:

if the signal metrics are not defined within the window, repeating the steps (a)-(c) with a different received signal.

7. The method in accordance with claim 5, further comprising the steps of:

reporting a received signal quality metric for the first carrier, the signal quality metric communicated from the user to a transmission station; and

determining a quality metric for the other related carriers based upon the signal quality metric for the first carrier.

8. The method in accordance with claim 5, wherein the search window is for duration of a plurality of periodic binary (PN) sequences, and the smaller window is for duration of a subset of the PN sequences contained in the search window.

9. An apparatus for reducing search time for acquiring multiple carriers, comprising:

means for using sequentially smaller search windows to identify a first carrier, wherein the sequentially smaller search windows is a sequence of narrowly defined search windows;

means for using the smallest of the sequentially smaller search windows used to identify the first carrier is used to identify other carriers in the multiple carriers in a multi-carrier communications network.

10. The apparatus as recited in claim 9, further comprising:

means for determining a quality metric for the other carriers based upon a signal quality metric determined for the first carrier.

11. The apparatus as recited in claim 9, wherein a narrowly defined search window comprises a subset of a plurality of periodic binary (PN) sequences contained in each search window of the sequentially smaller search windows.

12. The apparatus in accordance with claim 9, wherein if using the smallest of the sequentially smaller search windows fails to identify a second carrier of the other carriers in the multiple carriers, using a sequentially larger search window that was used in identifying the first carrier to identify the second carrier.

13. An apparatus for reducing search time for acquiring multiple carriers, comprising:

(a) means for receiving a signal associated with a first carrier;

(b) means for demodulating the signal to provide signal metrics;

(c) means for determining whether or not the signal metrics are defined within the boundaries of a search window;

(d) means for, if the signal metrics are defined within the search window, further demodulating the signal to provide additional signal metrics, the additional signal metrics used to determine whether or not the signal is defined within the boundaries of a smaller window; and

(e) means for, if the signal is accessible by a designated user, using the smaller window to search for other signals associated with related carriers in the multiple carrier and accessible by the designated user.

14. The apparatus in accordance with claim 13, further comprising:

means for, if the signal metrics are not defined within the window, repeating the operations (a)-(c) with a different received signal.

15. The apparatus in accordance with claim 13, further comprising of:

means for reporting a received signal quality metric for the first carrier, the signal quality metric communicated from the user to a transmission station; and

means for determining a quality metric for the other related carriers based upon the signal quality metric for the first carrier.

16. The apparatus as recited in claim 13, wherein the search window is for duration of a plurality of periodic binary (PN) sequences, and the smaller window is for duration of a subset of the PN sequences contained in the search window.