Wireless base station apparatus and wireless communication control method

• US 7,444,169 B2
• Filed: 04/27/2005
• Issued: 10/28/2008
• 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
• Primary Examiner(s): D AGOSTA, STEPHEN M
• Application Number:
  US11/115,319
• Publication Number:
  US 20050250540A1
• Time in Patent Office: 1,280 Days
• Field of Search: 455/63.1, 455/67.13, 455/62, 455/501, 455/504, 455/505, 455/561, 455/562.1, 455/506, 455/450, 455/454, 370/317, 370/322, 370/329, 370/341
• 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 a plurality of downlink radio quality information indicators reported from the wireless communications terminal device, said statistical processing including averaging said plurality of downlink radio quality information indicators over one of a first predetermined period of time and a second predetermined period of time, the one of the first and second predetermined periods of time selected for said averaging based on an estimated fading frequency determined from radio environment conditions;

a transport format determination unit configured to determine a downlink transport format based on the averaged plurality of downlink radio quality information indicators; 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 quality information offsetting unit configured to adjust the averaged plurality of downlink radio quality information indicators based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality to create offset-adjusting radio quality information,

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

3. The wireless base station apparatus of claim 2, 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 a fluctuation estimation result.

4. The wireless base station apparatus of claim 1, further comprising a radio environment estimation unit configured to estimate a fluctuation in a propagation environment between the wireless base station apparatus and the wireless communications terminal device and estimate a moving velocity of the wireless communications terminal device as the fluctuation in the propagation environment.

5. The wireless base station apparatus of claim 1, further comprising a radio environment estimation unit configured to estimate a fluctuation in a propagation environment between the wireless base station apparatus and the wireless communications terminal device based on time correlation among uplink channel estimation results.

6. 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, to create offset-adjusted radio quality information;

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

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

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

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.

7. The wireless base station apparatus of claim 6, wherein the radio environment estimation unit estimates uplink fading frequency as the fluctuation in the propagation environment.

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

9. The wireless base station apparatus of claim 6, wherein the radio environment estimation unit estimates the fluctuation in the radio environment based on time correlation among uplink channel estimation results.

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

a statistical processing unit configured to perform statistical processing on a plurality of downlink radio quality information indicators reported from a wireless communications terminal device, said statistical processing including averaging said plurality of downlink radio quality information indicators over one of a first predetermined period of time and a second predetermined period of time, the one of the first and second predetermined periods of time selected for said averaging based on an estimated fading frequency determined from radio environment conditions;

a radio quality information offsetting unit configured to adjust the averaged plurality of downlink radio quality information indicators based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality such that a block error rate becomes a target level and to create offset-adjusting radio quality information,

a transport format determination unit configured to determine a downlink transport format based on at least one of the averaged plurality of downlink radio quality information indicators and the offset-adjusted radio quality information; and

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

11. A wireless communication control method used in a wireless communications system, said method comprising the steps of:

determining an estimated fading frequency from radio environment conditions;

selecting one of a first predetermined period of time and a second predetermined period of time based on the estimated fading frequency determined from the radio environment conditions;

performing, in a statistical processing unit, statistical processing on a plurality of downlink radio quality information indicators reported from a wireless communications terminal device, said statistical processing including averaging the plurality of downlink radio quality information indicators reported from the wireless communication terminal device over the selected one of the first predetermined period of time and the second predetermined period of time;

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

transmitting a downlink channel in the determined downlink transport format.

12. The wireless communication control method of claim 11, further comprising the step of:

performing offset adjustment on the plurality of downlink radio quality information indicators reported from the wireless communication terminal device such that a block error rate becomes a target level, based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality, to create offset-adjusted radio quality information,

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

13. A method for communicating between a wireless base station communications apparatus and a wireless communications terminal device, comprising:

adjusting 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, such that a block error rate becomes a target level and to create offset-adjusted radio quality information;

determining a downlink transport format based on the offset-adjusted radio quality information;

transmitting a downlink channel with the determined downlink transport format; and

estimating a fluctuation in a propagation environment between the wireless base station apparatus and the wireless communications terminal device to produce a fluctuation estimation result,

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

14. A method for communicating between a wireless base station communications apparatus and a wireless communications terminal device, comprising:

averaging in the wireless base station communications apparatus a plurality of downlink radio quality information indicators reported from the wireless communications terminal device over one of a first predetermined period of time and a second predetermined period of time, the one of the first and second predetermined periods of time selected for said averaging based on an estimated fading frequency determined from radio environment conditions;

offset-adjusting the averaged plurality of downlink radio quality information indicators based on a downlink transmission confirmation message transmitted from the wireless communications terminal device and a required downlink quality, such that a block error rate becomes a target level and to create offset-adjusted radio quality information;

determining a downlink transport format based on at least one of the averaged plurality of radio quality information indicators and the offset-adjusted radio quality information; and

transmitting a downlink channel with the determined downlink transport format.