Call acceptance control method for CDMA mobile radio communication system and mobile station device

• US 6,801,515 B1
• Filed: 08/27/1998
• Issued: 10/05/2004
• Est. Priority Date: 12/27/1996
• Status: Expired due to Fees

• Current Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Inventors: Sato, Takaaki, Watanabe, Yasuyuki, Ishikawa, Yoshihiro
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): TRAN, PHUC H
• Application Number:
  US09/125,784
• Time in Patent Office: 2,231 Days
• Field of Search: 370/328, 370/331, 370/332, 370/333, 370/335, 370/342, 370/230, 370/329, 370/252, 455/437, 455/436, 455/432, 455/445, 455/450, 455/452.2
• US Class Current: 370/342
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A call admission control method and a mobile station device for a CDMA mobile communication system which is capable of not damaging a communication quality of a mobile station in communication even under a situation of large traffic, suppressing a possibility for degrading a communication qualities of mobile stations in communication with surrounding base stations sufficiently low, and improving efficiency without increasing the control signal traffic. A radio base station device measures an uplink interference amount and broadcasts it to a mobile station, and the mobile station acquires the uplink interference amount that is broadcast from the base station, calculates a required receiving level at the base station that is expected in a case where it is admitted to a connection target base station according to said acquired uplink interference amount, and judges that admission of the mobile station is refused in a case where it is judged that a prescribed communication quality cannot be satisfied according this calculated required receiving level and the uplink interference amount.

Claims

1. A call admission control method for a CDMA mobile communication that controls admission of calls for a frequency bandwidth shared by a plurality of mobile stations which carry out communications with radio base stations by a code division multiple access, the call admission control method for a CDMA mobile communication system characterized in that:

a radio base station broadcasts a call admission information, without request from the mobile station, indicating a state of own station regarding admission of a new call using a broadcast channel,

a mobile station acquires from a connection target information which is broad cast from a connection target radio base station through the broadcast channel, and judges admission permission/refusal of said mobile station according to this acquired call admission information, and

said mobile station carries out a call processing operation with respect to said radio base station when it is judged that admission is permitted, and the mobile station terminates the call processing operation when it is judged that admission is refused.

2. The call admission control method for a CDMA mobile communication system as described in claim 1, characterized in that the mobile station acquires the call admission information at respective radio base stations which are broadcast from surrounding radio base stations of the connection target radio base station through broadcast channels transmitted by respective radio base stations, and uses these acquired call admission information in judging admission permission/refusal of said mobile station.

3. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the call admission information indicates either permission or refusal regarding admission of a new call at own radio base station.

4. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the radio base station measures an uplink interference amount at own base station, and the call admission information is formed at least by said measured uplink interference amount and a prescribed threshold.

5. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the radio base station measures an uplink interference amount at own base station and calculates a remaining capacity at own base station according to this measured uplink interference amount, and the call admission information indicates at least this calculated remaining capacity.

6. The call admission control method for a CDMA mobile communication system as described in claim 1, characterized in that the radio base station measures an uplink interference amount at own base station, and the call admission information is formed at least by said measured uplink interference amount at own base station, and

the mobile station calculates a required receiving level at the radio base station that is expected in a case where it is admitted to the connection target radio base station, according to the interference amount acquired from the broadcast channel, and judges that admission of said mobile station is refused in a case where it is judged that own station cannot satisfy a required communication quality, according to said acquired uplink interference amount and said calculated required receiving level.

7. The call admission control method for a CDMA mobile communication system as described in claim 6, characterized in that the mobile station estimates an uplink interference amount after said mobile station is admitted, from the uplink interference amount at the base station and the required receiving level that is expected in a case where said mobile station is admitted, and judges that admission of said mobile station is refused in a case where this estimated uplink interference amount after admission exceeds a prescribed threshold.

8. The call admission control method for a CDMA mobile communication system as described in claim 6 or 7, characterized in that the radio base station measures an uplink interference amount at own base station, and the call admission information is formed at least by said measured uplink interference amount at own base station, and

the mobile station calculates an interference amount to be given to surrounding base stations that is expected in a case where said mobile station is admitted to the connection target radio base station, according to a required receiving level at the connection target radio base station that is expected in a case where it is admitted to the connection target radio base station, estimates an uplink interference amount at surrounding base stations after said mobile station is admitted to the connection target radio base station, from said acquired uplink interference amount at surrounding base stations, and said calculated interference amount to be given to surrounding base stations, and judges that admission of said mobile station is refused when this estimated uplink interference amount at surrounding base stations exceeds a prescribed threshold.

9. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the radio base station measures a transmission power of own base station, and the call admission information is formed at least by said measured transmission power value of the radio base station and a prescribed threshold.

10. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the radio base station measures a transmission power of own base station and calculates a remaining capacity at own base station according to said measured transmission power value of the radio base station, and the call admission information indicates at least this calculated remaining capacity.

11. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the call admission information is formed at least by a number of spread codes currently used within own radio base station or a number of hardware resources currently used within own radio base station, and a threshold corresponding to them.

12. The call admission control method for a CDMA mobile communication system as described in claim 1 or 2, characterized in that the radio base station calculates a remaining capacity at own base station according to a number of spread codes currently used within own radio-base station or a number of hardware resources currently used within own radio base station, and the call admission information indicates at least this calculated remaining capacity.

13. A mobile station device in a CDMA mobile communication system for controlling admission of calls for a frequency bandwidth shared by a plurality of mobile stations which carry out communications with radio base stations by a code division multiple access, the mobile station device for a CDMA mobile communication system characterized by having:

acquisition means for acquiring a call admission information indicating a state regarding admission of a new call at a radio base station which is broadcast from a connection target radio base station through a broadcast channel without request from the mobile station,

judging means for judging admission permission/refusal of said mobile station according to this acquired call admission information, and

call processing terminating means for carrying out a call processing operation at said mobile station with respect to said radio base station when it is judged that admission is permitted, and for terminating the call processing operation when it is judged that admission is refused.

14. The mobile station device for a CDMA mobile communication system as described in claim 13, characterized in that the acquisition means also acquires the call admission information at respective radio base stations which are broadcast from surrounding base stations of the connection target radio base stations through broadcast channels transmitted by respective base stations.

15. The mobile station device for a CDMA mobile communication system as described in claim 13, characterized in that the acquisition means acquires an uplink interference amount from the call admission information which is broadcast from the connection target radio base station, and

the judging means calculates a required receiving level at the radio base station that is expected in a case where it is admitted to the connection target radio base station, according to the interference amount acquired from the broadcast channel, and judges that admission of said mobile station is refused in a case where it is judged that own station cannot satisfy a required communication quality, according to said acquired uplink interference amount and said calculated required receiving level.

16. The mobile station device for a CDMA mobile communication system as described in claim 15, characterized in that the judging unit estimates an uplink interference amount after said mobile station is admitted, from the uplink interference amount at the base station and the required receiving level that is expected in a case where the mobile station is admitted, and judges that admission of said mobile station is refused in a case where this estimated uplink interference amount after admission exceeds a prescribed threshold.

17. The mobile station device for a CDMA mobile communication system as described in claim 15 or 16, characterized in that the acquisition means acquires an uplink interference amount at the base station from the call admission information that is broadcast through the broadcast channel, and

the judging unit calculates an interference amount to be given to surrounding base stations that is expected in a case where said mobile station is admitted to the connection target radio base station, according to a required receiving level at the connection target radio base station that is expected in a case where it is admitted to the connection target radio base station, estimates an uplink interference amount at surrounding base stations after said mobile station is admitted to the connection target radio base station, from said acquired uplink interference amount at surrounding base stations, and said calculated interference amount to be given to surrounding base stations, and judges that admission of said mobile station is refused when this estimated uplink interference amount at surrounding base stations exceeds a prescribed threshold.