Pilot signal strength adjusting method in mobile communication system

• US 6,539,206 B1
• Filed: 03/25/1999
• Issued: 03/25/2003
• Est. Priority Date: 03/26/1998
• Status: Expired due to Term

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: SK Hynix Inc.
• Inventors: Min, Seung-Hyun, Kang, Dae-Goo, Koo, Woo-Seok
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): CRAVER, CHARLES R
• Application Number:
  US09/276,299
• Time in Patent Office: 1,461 Days
• Field of Search: 455/422, 455/423, 455/424, 455/432, 455/434, 455/435, 455/525, 455/522, 455/450-453, 455/24, 455/70, 455/560, 455/561, 455/67.1, 455/245--24, 455/436-444, 370/331-334, 370/341
• US Class Current: 455/67.11
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/30 Connection release

Abstract

A pilot signal strength adjusting method in mobile communication systems, in which strength of pilot signals generating in CPTU installed in base stations is automatically adjusted according to sum of calls which are allocated to reference frequencies of the base stations so that hard hand off to different frequencies is performed smoothly between adjacent base stations, wherein when a mobile station uses service coverage area of a base station which is installed with CPTU Common Pilot Transmit Unit, or calls of mobile stations are concentrated on a reference frequency of the base station which is installed with the CPTU Common Pilot Transmit Unit, strength of pilot signal is adjusted by increasing and/or decreasing power of CPCA installed in the CPTU by using the sum of calls allocated to a reference frequency of a base station installed with the CPTU, predetermined threshold values of set-up calls, predetermined user-units and predetermined power up/down values, so that the base station may smoothly perform hard handoff between frequencies through optimization of cell radius by adjusting pilot signal strength of CPCA Common Pilot Control Assembly, thereby maintaining high quality of telephone conversation service.

Claims

1. A pilot signal strength adjusting method in a mobile communication system comprising the steps of:

checking total number of calls allocated to a current reference frequency of a base station which is installed with a CPTU Common Pilot Transmit Unit, or calls of mobile stations concentrated on a reference frequency of the base station which is installed with the CPTU Common Pilot Transmit Unit, and comparing the total number of calls to a predetermined threshold value of set-up calls when either a call set-up or a call release is requested by the mobile station;

adjusting strength of a pilot signal by increasing and/or decreasing power of a CPCA Common Pilot Control Assembly installed in the CPTU Common Pilot Transmit Unit; and

using a total number of calls which are located to reference frequencies of the base station so that hard handoff to different frequencies may be performed smoothly between adjacent base stations, if the call release is performed by the user unit basis.

2. The method according to claim 1, including increasing power of the CPCA Common Pilot Control Assembly by the subscribers unit if a total number of calls allocated to a current reference frequency is larger than the threshold value of the set-up calls, and the mobile station requests call set-up to the reference frequency of the base station.

3. The method according to claim 1, including decreasing the power of the CPCA Common Pilot Control Assembly by the user-unit if the total number of calls allocated to a current reference frequency is larger than the threshold value of the set-up calls, and the mobile station requests a call release from the reference frequency of the base station.

4. The method according to claim 1, returning the power of the CPCA Common Pilot Control Assembly to its initial set-up value unit when a total number of calls does not exceed the threshold value of the set-up calls.

5. The method according to claim 1, wherein the power up/down value is set up to a variable value in response to a change of the number of the users in a user-unit.

6. A pilot signal strength adjusting method in a mobile communication system, comprising:

(a) checking a total number of calls allocated to a current reference frequency of a base station;

(b) comparing the total number of calls allocated to the current reference frequency of the base station to a predetermined threshold value of set-up calls when a mobile station requests a call set-up or a call release using the reference frequency of the base station;

(c) if the total number of calls exceed the predetermined threshold value of set-up calls, determining whether the call set-up or the call release is performed by a user-unit;

(d) decrementing pilot signal strength by decreasing power of CPCA Common Pilot Control Assembly by a predetermined power up/down value if the call set-up is performed by the user-unit; and

(e) incrementing pilot signal strength by increasing power of the CPCA Common Pilot Control Assembly by the predetermined power up/down value if the call release performed by the user-unit basis.

7. The method according to claim 6, further comprising recovering the power of the CPCA to its predetermined initial value if the total number of calls allocated to the current reference frequency of the base station is not greater than the predetermined threshold value of set-up calls.

8. The method according to claim 6, further comprising repeating steps (a)-(d) if the call release is not performed by the user-unit basis in step (c).

9. The method according to claim 6, wherein the power up/down value in the steps (d) and (e) is set up to a variable value in response to a change of the number of the users in a user-unit.