Wireless base station apparatus and wireless communication control method

• US 20050250540A1
• Filed: 04/27/2005
• Published: 11/10/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Usuda, Masafumi, Hanaki, Akihito, Ishii, Hiroyuki, Imamura, Yoshimasa
• Granted Patent: US 7,444,169 B2
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/20 using signal quality detector
• 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 72/542 using measured or perceived quality
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A wireless base station apparatus (100) used in a wireless communications system includes a statistical processing unit (140) that performs statistical processing on downlink radio quality information reported from a wireless communications terminal device; a radio quality information offsetting unit (160) that adjusts the statistically processed downlink radio quality information based on a downlink transmission confirmation (ACK/NACK/DTX) message transmitted from the wireless communications terminal device and a required downlink quality; a transport format determination unit (170) that determines a downlink transport format based on the statistically processed radio quality information or the offset-adjusted radio quality information; and a transmitting unit (111) that transmits a downlink channel with the determined downlink transport format.

Claims

1. A wireless base station apparatus used in a wireless communications system to communicate with a wireless communications terminal device, comprising:

a statistical processing unit configured to perform statistical processing on downlink radio quality information reported from the wireless communications terminal device;

a transport format determination unit configured to determine a downlink transport format based on the statistically processed radio quality information; and

a transmitting unit configured to transmit a downlink channel with the determined downlink transport format.

2. The wireless base station apparatus of claim 1, further comprising:

a radio environment estimation unit configured to estimate fluctuation in the propagation environment between the wireless base station apparatus and the wireless communications terminal device;

wherein the statistical processing unit is configured to average the downlink radio quality information for a prescribed period of time determined based on the fluctuation estimation result, and the transport format determination unit is configured to determine the downlink transport format based on the averaged downlink radio quality information.

3. The wireless base station apparatus of claim 2, further comprising:

a radio quality information offsetting unit configured to adjust the averaged downlink radio quality information based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality;

wherein the transport format determination unit is configured to determine the downlink transport format based on the offset-adjusted radio quality information.

4. The wireless base station apparatus of claim 3, wherein at least one of ON/OFF operation of the radio quality information offsetting unit, the required downlink quality, and an offset adjustment step size used in the radio quality information offsetting unit is controlled according to the fluctuation estimation result.

5. The wireless base station apparatus of claim 2, wherein the radio environment estimation unit estimates uplink fading frequency as the fluctuation in the propagation environment.

6. The wireless base station apparatus of claim 2, wherein the radio environment estimation unit estimates a moving velocity of the wireless communications terminal device as the fluctuation in the propagation environment.

7. The wireless base station apparatus of claim 2, wherein the radio environment estimation unit estimates the fluctuation in the radio environment based on time correlation among uplink channel estimation results.

8. A wireless base station apparatus configured to perform wireless communication with a wireless communications terminal device, comprising:

a radio quality information offsetting unit configured to adjust downlink radio quality information reported from the wireless communications terminal device, based on a downlink transmission confirmation message transmitted from the wireless communication terminal and a required downlink quality;

a transport format determination unit configured to determine a downlink transport format based on the offset-adjusted radio quality information; and

a transmitting unit configured to transmit a downlink channel with the determined downlink transport format.

9. The wireless base station apparatus of claim 8, further comprising:

a radio environment estimation unit configured to estimate fluctuation in the propagation environment between the wireless base station apparatus and the wireless communications terminal device;

wherein at least one of ON/OFF operation of the radio quality information offsetting unit, the required downlink quality, and an offset adjustment step size used in the radio quality information offsetting unit is controlled according to the fluctuation estimation result.

10. The wireless base station apparatus of claim 9, wherein the radio environment estimation unit estimates uplink fading frequency as the fluctuation in the propagation environment.

11. The wireless base station apparatus of claim 9, wherein the radio environment estimation unit estimates a moving velocity of the wireless communications terminal device as the fluctuation in the propagation environment.

12. The wireless base station apparatus of claim 9, wherein the radio environment estimation unit estimates the fluctuation in the radio environment based on time correlation among uplink channel estimation results.

13. A wireless base station apparatus used in a wireless communications system comprising:

a statistical processing unit that performs statistical processing on downlink radio quality information reported from a wireless communications terminal device;

a radio quality information offsetting unit that adjusts the statistically processed downlink radio quality information based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality;

a transport format determination unit that determines a downlink transport format based on the statistically processed radio quality information or the offset-adjusted radio quality information; and

a transmitting unit that transmits a downlink channel with the determined downlink transport format.

15. The wireless communication control method of claim 13, further comprising the steps of:

performing offset adjustment on the downlink radio quality information reported from the wireless communication terminal device, based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality;

wherein the determination step includes determining the downlink transport format based on the offset-adjusted radio quality information.

14. A wireless communication control method comprising the steps of:

averaging downlink radio quality information reported from a wireless communication terminal device;

determining a downlink transport format based on the averaged radio quality information; and

transmitting a downlink channel in the determined downlink transport format.