Method of searching reverse traffic channels in a CDMA mobile radio communication system

• US 6,226,282 B1
• Filed: 12/23/1998
• Issued: 05/01/2001
• Est. Priority Date: 12/27/1997
• Status: Expired due to Term

• Current Assignee: Hyundai Syscomm, Inc. (Hyundai Motor Group)
• Original Assignee: SK Hynix Inc.
• Inventors: Chung, Chae-Hun
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Nguyen, Phuongchau Ba
• Application Number:
  US09/220,229
• Time in Patent Office: 860 Days
• Field of Search: 370/335, 370/320, 370/342, 370/350, 370/503, 375/140, 375/141, 375/145, 375/149, 375/142
• US Class Current: 370/335
• 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: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method of searching reverse traffic channels in a code division multiple access (CDMA) mobile radio communication system for allowing for acquisition of reverse traffic channels without increase or decrease of size of a search window for traffic channels, the method comprising the steps of: storing an offset by a propagation delay after acquiring a reverse access channel; determining whether or not a pseudonoise (PN) random delay is employed for the reverse access channel and, when the PN random delay is used, calculating the PN random delay using a hash function with a factor of an electronic serial number (ESN) transmitted from a mobile station; computing the stored offset and the PN random delay and setting a new offset to a result of the computing; setting a center of a search window for searching the reverse traffic channel to the new offset and establishing the search window; and searching a reverse traffic channel preamble with the established search window.

Claims

1. A method of searching reverse traffic channels in a code division multiple access (CDMA) mobile radio communication system acquiring an offset by a propagation delay after acquiring a reverse access channel, calculating a PN random delay using a hash function with a factor of an electronic serial number (ESN), and setting a search window for searching the reverse traffic channel, the method comprising the steps of:

computing said acquired offset and said PN random delay and setting a new offset to a result of the computing; and

determining a center of said search window as a delayed time point by the new set offset from the time of a base station system for searching said reverse traffic channel to thereby set said search window.

2. The method according to claim 1, wherein said new offset is set to a result value of subtracting said calculated PN random delay from said acquired offset.

3. A method of searching reverse traffic channels in a code division multiple access (CDMA) mobile radio communication system, by acquiring and storing an offset by a propagation delay after acquiring a reverse access channel, setting a center of a search window to said offset, and determining whether or not a pseudonoise (PN) random delay is applied to said reverse access channel;

and when it is determined that said PN random delay is applied to the reverse access channel, calculating said PN random delay using a hash function with a factor of an electronic serial number (ESN) transmitted from a mobile station;

the method comprising steps of;

establishing a size of the search window to a value equal to or greater than a predetermined number times said calculated PN random delay; and

searching a reverse traffic channel preamble with said established search window, and determining a center of said search window as a delayed time point by the new set offset from the time of a base station system for searching said reverse traffic channel to thereby set said established search window.

4. The method according to claim 3, wherein said predetermined number is two.