Communication Control Method, Communication Control System and Its Control Program

• US 20090131094A1
• Filed: 06/09/2006
• Published: 05/21/2009
• Est. Priority Date: 06/17/2005
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Natsume, Kouhei
• Granted Patent: US 8,238,957 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo

Abstract

In a communication control method which realizes the quick and stable provision of a service by increasing efficiency in transmission power control, a target SIR setting part 18 controls downlink transmission power from a base station so that the T-SIR will be equal to the SIR measured in a known inner loop, by increasing a target signal interference ratio (T-SIR) by a first predetermined value when a reception field level of a common pilot channel before the establishment of synchronization of a dedicated control channel, which is provided by the quality measurement part 12, falls below a first threshold selected by a target quality setting part 14 depending on the reception quality of a DPDCH, and decreasing the target signal interference ratio (T-SIR) by a second predetermined value when the reception field level of the common pilot channel exceeds a second threshold selected by the target quality setting part 14 depending on the reception quality of the DPDCH.

Claims

1. A communication control method to control transmission power through a first wireless channel which connects between a first wireless communication apparatus and a second wireless communication apparatus, comprising:

establishing a second wireless channel which connects between said first wireless communication apparatus and said second wireless communication apparatus;

said second wireless communication apparatus receiving a signal sent from said first wireless communication apparatus via the second wireless channel; and

controlling signal transmission power through said first wireless channel according to said reception condition of the signal.

2. The communication control method according to claim 1, wherein said first wireless communication apparatus is a base station in a mobile communication network;

said second wireless communication apparatus is a mobile terminal which is connected with said base station via said first wireless channel and said second wireless channel;

said first wireless channel is a dedicated control channel; and

said second wireless channel is a common pilot channel.

3. The communication control method according to claim 2, wherein the reception condition of said signal from said common pilot channel is a reception field level, and wherein the control of transmission power through said dedicated control channel is performed by variably setting, within a measured signal interference ratio and a target signal interference ratio which are used to control transmission power for said dedicated control channel, said target signal interference ratio according to the reception field level of said common pilot channel before the establishment of synchronization of said dedicated control channel and a threshold determined based on the reception error rate of the dedicated physical data channel.

17. A control program, comprising causing a computer to execute the communication control method of claim 1.

4. A communication control system, comprising a first measurement unit to measure the signal interference ratio of a first wireless channel which is established with a base station;

a setting unit to set a target signal interference ratio required for communication via said first wireless channel; and

a control unit to control transmission power transmitted from said base station via said first wireless channel based on said signal interference ratio measured by said first measurement unit and said target signal interference ratio set by said setting unit;

wherein

a second measurement unit is provided to measure the reception condition of a signal through a second wireless channel which is established with a base station before said first wireless channel is established; and

said target signal interference ratio set by said setting unit is variably set according to the reception condition of said signal which is measured by said second measurement unit.

5. The communication control system according to claim 4, wherein said first wireless channel is a dedicated control channel;

said second wireless channel is a common pilot channel; and

the reception condition of said signal is a reception field level.

6. The communication control system according to claim 5, wherein said setting unit includes a threshold setting unit to output a first threshold which is set based on the reception field level of said common pilot channel and the measured reception quality value of the dedicated physical data channel;

and

if said reception field level falls below said first threshold, said target signal interference ratio is set to a value increased by a first predetermined value.

7. The communication control system according to claim 6, wherein said setting unit includes a message retransmission unit to retransmit a message if the reception quality is still insufficient after increasing said target signal interference ratio by the first predetermined value;

wherein

the first predetermined value is incremented by the predetermined value at every retransmission by said message retransmission unit, and said target signal interference ratio is set to said incremented value.

8. The communication control system according to claim 6, wherein said first threshold is selected as said measured reception quality value as of a measurement time for said reception field level when the measured reception quality value exceeds a tolerable reception quality value by 100%.

9. The communication control system according to claim 6, wherein said setting unit includes a threshold setting unit to output a second threshold higher than said first threshold which is set based on the reception field level of said common pilot channel and the measured reception quality value of the dedicated physical data channel;

and

if said reception field level exceeds said second threshold, said target signal interference ratio is set to a value decreased by a second predetermined value.

10. The communication control system according to claim 9, wherein said second threshold is selected as said measured reception quality value as of a measurement time for said reception field level when the measured reception quality value falls below a tolerable reception quality value by 100%.

11. The communication control system according to claim 8, wherein said measured reception quality value is a reception error rate.

12. The communication control system according to claim 4, wherein said setting unit sets said target signal interference ratio by increasing and/or decreasing said target signal interference ratio when the setting unit determines that communication quality is not sufficient.

13. The communication control system according to claim 7, wherein said setting unit sets said target signal interference ratio by increasing and/or decreasing said target signal interference ratio when the setting unit determines that battery usage exceeds a predetermined usage level.

14. The communication control system according to claim 4, wherein said setting unit sets said target signal interference ratio by increasing and/or decreasing said target signal interference ratio when the setting unit determines that the condition of wireless resources exceeds a predetermined condition of wireless resources.

15. The communication control system according to claim 4, wherein said setting unit sets said target signal interference ratio in such a manner that the start of setting control is suppressed according to the history of transmission power control.

16. The communication control system according to claim 4, wherein said setting unit sets said target signal interference ratio periodically or non-periodically according to battery usage on the mobile terminal or system capacity on the base station.

18. A control program, comprising causing a computer to control the communication control system of claim 4.