APPARATUS FOR CONTROLLING MODULATION AND CODING SCHEME DEPENDING ON COMMUNICATION SPEED

• US 20140321292A1
• Filed: 03/24/2014
• Published: 10/30/2014
• Est. Priority Date: 04/24/2013
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: YOKOYAMA, Hitoshi
• Granted Patent: US 9,642,092 B2
• Time in Patent Office: Days
• US Class Current: 370/242
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/262 taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A base station performs wireless communication with a first apparatus, and performs wired communication with a second apparatus. When a first communication speed corresponding to a wireless quality of the wireless communication is higher than a second communication speed of the wired communication, the base station changes a currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed.

Claims

1. A base station that performs wireless communication with a first apparatus and that performs wired communication with a second apparatus, the base station comprising:

a control unit configured to change, when a first communication speed corresponding to a wireless quality of the wireless communication is higher than a second communication speed of the wired communication, a currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed.

2. The base station of claim 1, further comprising

an error rate measurement unit configured to measure a wireless error rate, wherein

the control unit is configured to determine, when the wireless error rate is lower than or equal to a certain percentage, whether the first communication speed is higher than the second communication speed, and change, when the first communication speed is higher than the second communication speed, the currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed.

3. The base station of claim 2, wherein

the control unit is configured to reduce, after changing the currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed, a transmit power of a wireless signal of the wireless communication.

4. The base station of claim 3, wherein

the control unit is configured to reduce the transmit power of the wireless signal while maintaining the wireless error rate of wireless communication performed at the reduced transmit power, lower than or equal to the certain percentage.

5. The base station of claim 4, wherein

the control unit is configured:

to reduce the transmit power of the wireless signal in units of a certain amount of power;

to increase, when the wireless error rate of the wireless communication performed at the reduced transmit power has exceeded the certain percentage, the reduced transmit power of the wireless signal by the certain amount of power; and

to perform wireless communication at the increased transmit power.

6. The base station of claim 3, wherein

the control unit is configured to reduce the transmit power of the wireless signal while maintaining a third communication speed higher than the second communication speed, the third communication speed being obtained by correcting the first communication speed based on the wireless error rate.

7. The base station of claim 6, wherein

the control unit is configured:

to reduce the transmit power of the wireless signal in units of certain amounts of power;

to increase, when the third communication speed obtained based on the wireless error rate measured at the reduced transmit power has become lower than or equal to the second communication speed, the reduced transmit power of the wireless signal by the certain amount of power; and

to perform the wireless communication at the increased transmit power.

8. The base station of claim 1, further comprising

a memory configured to store information that associates the wireless quality with a communication speed, wherein

the control unit is configured to select, from the information, a communication speed associated with the wireless quality, and determine the selected communication speed as the first communication speed.

9. The base station of claim 8, wherein

the information further associates the wireless quality, the communication speed, and the modulation and coding scheme, in association with one another;

and

the control unit is configured to change the currently set modulation and coding scheme to a modulation and coding scheme associated with a communication speed that is closest to the second communication speed.

10. A communication system comprising:

a first apparatus provided with a wireless communication function;

a second apparatus provided with a wired communication function; and

a base station configured;

to perform wireless communication with the first apparatus, and

to perform wired communication with the second apparatus, wherein

the base station includes a control unit configured to change, when a first communication speed corresponding to a wireless quality of the wireless communication is higher than a second communication speed of the wired communication, a currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed.

11. A communication method executed by a base station that performs wireless communication with a first apparatus and that performs wired communication with a second apparatus, the communication method comprising:

changing, by the base station, when a first communication speed corresponding to a wireless quality of the wireless communication is higher than a second communication speed of the wired communication, a currently set modulation and coding scheme to a modulation and coding scheme corresponding to the second communication speed.