Channel assignment method for multi-FA CDMA cellular systems

• US 6,999,772 B2
• Filed: 06/03/2003
• Issued: 02/14/2006
• Est. Priority Date: 02/24/1998
• Status: Expired due to Fees

• Current Assignee: SK Telecom Co., Ltd.
• Original Assignee: SK Telecom Co., Ltd.
• Inventors: Oh, Se Hyun, Lee, Seong Jae, Lee, Youl No, Jang, Gab Seok, Song, Bong Yong, Kim, Jeong Chul
• Primary Examiner(s): MEHRPOUR, NAGHMEH
• Application Number:
  US10/452,633
• Publication Number:
  US 20030193917A1
• Time in Patent Office: 987 Days
• Field of Search: 370/441, 370320-335, 370/319, 370/450, 370341-349, 370/469, 455/451, 455/452.1, 455/452.2, 455/62, 455/63.1, 455/450, 455/445, 455/453
• US Class Current: 455/450
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for assigning a channel in multi-FA CDMA mobile communication system according to the received power prevents communication quality of a FA from being inferior to that of the others by managing the interference level of the FA. The method comprises the steps of: comparing a first threshold value with received power when the base station receives a new call request; assigning a traffic channel in a first FA of the request, if the received power is less than the first threshold value, and searching a second FA of which received power is least, if not; comparing a second threshold value with the received power of the second FA; and assigning a traffic channel in the second FA if the received power is less than the second threshold value, and rejecting the request, if not.

Claims

1. A channel assignment method for multi-FA (Frequency Assignment) CDMA cellular systems in which a base station communicates a plurality of mobile stations, said method comprising the steps of:

comparing a first threshold value with a cell loading factor of a first FA when the base station receives a new call request in said first FA;

assigning a first traffic channel in the first FA, if the cell loading factor of said first FA is less than the first threshold value, otherwise searching for a second FA of which the cell loading factor is minimum;

comparing a second threshold value with the cell loading factor of the second FA; and

assigning a second traffic channel in the second FA, if the cell loading factor of the second FA is less than the second threshold value, otherwise rejecting the request;

wherein the cell loading factor of each of the first and second FAs is determined by the following equation;

cell loading factor=1−

thermal noise power/received power.

2. The method as claimed in claim 1, further comprising the step of assigning a traffic channel in the first FA of the request, if there is an available channel in the first FA when the base station receives a handoff call request.

3. A channel assignment method for use in a multi-FA (Frequency Assignment) CDMA cellular system in which a base station communicates a plurality of mobile stations, said method comprising the steps of:

a. receiving, at said base station, a new call request from a mobile station in a first FA;

b. determining a cell loading factor at said base station in said first FA;

c. comparing a first threshold value with the cell loading factor in said first FA;

d. d.i. if the cell loading factor in said first FA is less than the first threshold value, assigning a first traffic channel in said first FA to said mobile station in response to said new call request;

d.ii. if the cell loading factor in said first FA is not less than the first threshold value,

d.ii.1. determining cell loading factors at said base station in FAs other than said first FA;

d.ii.2. among said other FAs, determining the FA having the lowest cell loading factor as a second FA;

d.ii.3. comparing a second threshold value with the cell loading factor in said second FA;

d.ii.4. if the cell loading factor in said second FA is less than the second threshold value, assigning a second traffic channel in said second FA to said mobile station in response to said new call request;

otherwise, rejecting said new call request;

wherein the cell loading factor in each of the FAs is determined by the following equation;

cell loading factor=1−

thermal noise power/received power.

4. The method of claim 3, further comprising the step of assigning a traffic channel in the first FA of the request, if there is an available channel when the base station receives a handoff call request.