Mobile communication congestion control system

• US 5,454,026 A
• Filed: 04/06/1993
• Issued: 09/26/1995
• Est. Priority Date: 04/07/1992
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Tanaka, Shoji
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): OEHLING, GEORGE J
• Application Number:
  US08/043,346
• Time in Patent Office: 903 Days
• Field of Search: 379/58, 379/59, 379/60, 455/33.1, 455/33.2, 455/54.1, 455/54.2, 455/56.1
• US Class Current: 455/437
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A mobile communication system contains a mobile switching center connected to a plurality of base stations constituting a radio service zone and a plurality of mobile stations. The mobile switching center monitors the usage of a traffic channel for each radio service zone and has a usage threshold value for each radio service zone, and informs those to the mobile station via the base station. The busy mobile station compares the traffic channel usage information and the usage threshold value information and the radio zone communicated. When the traffic channel usage is greater than the usage threshold value, the mobile station selects a hand-over radio zone destination based on the received signal strength and quality, and the traffic channel usage information and the usage threshold value information of the adjacent zone, and then transmits a hand-over request designating the hand-over radio zone destination to the mobile switching center.

Claims

1. A mobile communication congestion control system comprising:

information transmitting means located in a mobile switching center connected to respective base stations of a plurality of radio zones constituting a service area, the information transmitting means transmitting through said base stations traffic channel usage information and usage threshold value information for each of said plurality of radio zones to busy and idle mobile stations located in said plurality of radio zones;

each said mobile station including;

information receiving means for receiving from said information transmitting means the traffic channel usage information and the usage threshold value information of a first radio zone in which said mobile station is located and of adjacent radio zones;

comparing means for comparing the traffic channel usage information and the usage threshold value information of the first radio zone to monitor a congestion state of the first radio zone;

level monitoring means for measuring and monitoring a level of a received signal strength in a control channel from each of said adjacent radio zones; and

selecting and transmitting means for;

(a) selecting one of the adjacent radio zones as a second radio zone to which said mobile station is to be handed-over based on;

(A) the level of the received signal strength in the control channel from the second radio zone being not less than a predetermined hand-over level, and

(B) the traffic channel usage of the second radio zone being less than the usage threshold value of the second radio zone, and

(b) transmitting a hand-over request designating the second radio zone as a hand-over destination to said mobile switching center when the traffic channel usage of the first radio zone is not less than the usage threshold value of the first radio zone,

wherein said selecting and transmitting means selects, as the hand-over destination, one of the adjacent radio zones in which the level of the received signal strength is highest and the traffic channel usage thereof is less than the associated usage threshold value, and

when there are a plurality of adjacent radio zones having the same highest level of the received signal strength, said selecting and transmitting means selects, as the hand-over destination, one of the adjacent radio zones having a largest difference obtained by subtracting the traffic channel usage thereof from the associated usage threshold value.

2. A system according to claim 1, wherein said information transmitting means transmits at least the traffic channel usage information and the usage threshold value information of the plurality of radio zones to said mobile stations at every predetermined period of time.

3. A system according to claim 1, wherein said information transmitting means comprises traffic monitor means for measuring and monitoring a mobile station traffic for every radio zone, memory means for storing the usage threshold value information, and control means for transmitting the traffic channel usage information and the usage threshold value information of each radio zone to said mobile station through said base stations in accordance with outputs from said traffic monitor means and said memory means.

4. A system according to claim 1, wherein said selecting and transmitting means selects one of the adjacent radio zones, as the hand-over destination, on the basis of the level of the received signal strength and a level of a received signal quality.

5. A system according to claim 1, wherein the level monitoring means further monitors a level of the received signal strength in a communicating channel of the first radio zone, and said selecting and transmitting means selects one of the adjacent radio zones when the level of the received signal strength of said one of the adjacent radio zones is not less than the predetermined hand-over level and higher than that of the first radio zone.

6. A mobile communication congestion control system comprising:

information transmitting means located in a mobile switching center connected to respective base stations of a plurality of radio zones constituting a service area, the information transmitting means transmitting traffic channel image information and usage threshold value information for each radio zone to busy and idle mobile stations located in said plurality of radio zones;

each said mobile station including;

information receiving means for receiving from said information transmitting means the traffic channel usage information and the usage threshold value information of a first radio zone in which said mobile station is located and of adjacent radio zones;

level monitoring means for measuring and monitoring levels of received signal strengths in a communicating channel of the first radio zone, and in a control channel from each of the adjacent radio zones;

comparing means for comparing the traffic channel usage information and the usage value information of the first radio zone to monitor a congestion state of the first radio zone; and

selecting and transmitting means for selecting one of the adjacent radio zones as a second radio zone to which said mobile station is to be handed-over and for transmitting a hand-over request for designating the second radio zone as a hand-over destination to said mobile switching center when the traffic channel usage of the first radio zone is not less than the usage threshold value of the first radio zone, and the level of the received signal strength from the second radio zone is not less than a predetermined hand-over level and higher than that of the first radio zone,

wherein said selecting and transmitting means selects, as the hand-over destination, one of the adjacent radio zones in which the level of the received signal strength is highest and the traffic channel usage thereof is less than the associated usage threshold value, and

wherein said are plurality of adjacent radio zones having the same highest level of the received signal strength, said selecting and transmitting means selects, as the hand-over destination, one of the adjacent radio zones having a largest difference obtained by subtracting the traffic channel usage thereof from the associated usage threshold value.