Wireless communication system for multi-hop connection, source station, radio station and pilot signal used therein

• US 20030165127A1
• Filed: 03/03/2003
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Yoshino, Hitoshi, Otsu, Toru, Takeda, Shinji, Fujiwara, Atsushi
• Granted Patent: US 7,352,729 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 40/16 based on interference
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A destination station 3 in a wireless communication system for a multi-hop connection selects a transmission path having a minimum total of required transmission power values of respective stations on the transmission path among candidates of the transmission path from a source station 1 to the destination station 3 and transmits a pilot signal to the source station 1 and a relay station 2, the pilot signal including identification information about the respective stations on the selected transmission path and required transmission power values thereof. Thus, the source station 1 and the relay station 2, which have received this pilot signal, can determine the transmission path having the minimum total of the required transmission power values by use of the identification information included in the received pilot signal.

Claims

1. A wireless communication system for a multi-hop connection, which performs signal transmission between a source station, plurality of relay stations and a destination station,

the source station comprising:

a transmission unit configured to transmit a pilot signal including identification information of the source station,

the relay station comprising;

a reception unit configured to receive a pilot signal;

a required transmission power total calculation unit configured to specify a transmission path from the source station to the relay station by use of information included in the received pilot signal and calculate a total of required transmission power values of respective stations on the transmission path;

a selection unit configured to select a transmission path having a minimum total of the required transmission power values among candidates of the specified transmission path; and

a transmission unit configured to transmit a pilot signal including identification information about respective stations on the selected transmission path and required transmission power values thereof, and the destination station comprising;

a reception unit configured to receive a pilot signal;

a required transmission power total calculation unit configured to specify a transmission path from the source station to the destination station by use of information included in the received pilot signal and calculate a total of required transmission power values of respective stations on the transmission path;

a selection unit configured to select a transmission path having a minimum total of the required transmission power values among candidates of the specified transmission path; and

a transmission unit configured to transmit a pilot signal including identification information about respective stations on the selected transmission path and required transmission power values thereof.

2. The wireless communication system for a multi-hop connection of claim 1, wherein

the transmission units transmit a pilot signal at a transmission power prescribed in respective transmission power values, respectively,

the reception units have a received SIR measurement unit configured to measure a received SIR obtained when receiving the pilot signal,

the required transmission power total calculation units have

a power value calculation sub-unit configured to calculate a required transmission power value in an immediately preceding station, from which the pilot signal is transmitted, by use of at least one of a transmission power value of the immediately preceding station, the measured received SIR and a desired received SIR, and

a total calculation sub-unit configured to calculate a total of required transmission power values of respective stations on the transmission path by use of required transmission power values included in a received pilot signal and the required transmission power value calculated for the pilot signal by the power value calculation sub-unit.

3. The wireless communication system for a multi-hop connection of claims 1 or 2, wherein

the reception units receive a pilot signal for a fixed period of time,

the selection units select a transmission path having a minimum total of required transmission power values among candidates of the transmission path for the pilot signal received in this fixed period of time.

4. A source station performing signal transmission with at least one of a relay station and a destination station,

the source station comprising:

a pilot signal generation unit configured to generate a pilot signal including identification information and transmission power values of the source station; and

a transmission unit configured to transmit the pilot signal by use of a power prescribed in the transmission power values.

5. A radio station performing signal transmission with at least one of a source station, a relay station and a destination station,

the radio station comprising:

a reception unit configured to receive a pilot signal;

a required transmission power total calculation unit configured to specify a transmission path from the source station to the relay station by use of information included in the received pilot signal and calculate a total of required transmission power values of respective stations on the transmission path;

a selection unit configured to select a transmission path having a minimum total of the required transmission power values among candidates of the specified transmission path; and

a transmission unit configured to transmit a pilot signal including identification information about respective stations on the selected transmission path and required transmission power values thereof.

6. The radio station of claim 5, further comprising a received SIR measurement unit configured to measure a received SIR obtained when receiving the pilot signal,

the transmission unit transmits a pilot signal at a transmission power prescribed in a transmission power value,

the required transmission power total calculation unit has a power value calculation sub-unit configured to calculate a required transmission power value in an immediately preceding station, from which the pilot signal is transmitted, by use of at least one of a transmission power value of the immediately preceding station, the measured received SIR and a desired received SIR and

a total calculation sub-unit configured to calculate a total of required transmission power values of respective stations on the transmission path by use of required transmission power values included in a received pilot signal and the required transmission power value calculated for the pilot signal by the power value calculation sub-unit.

7. The radio station of claim 6, wherein the power value calculation sub-unit uses a transmission power value included in the received pilot signal.

8. The radio station of claim 7, wherein

the transmission unit transmits a pilot signal including a transmission power value of the radio station.

9. The radio station of claim 6, wherein the power calculation sub-unit uses previously stored transmission power values for other stations.

10. The radio station of claim 5, wherein

the selection unit has

a storage sub-unit configured to store identification information and required transmission power values and

a comparison sub-unit configured to compare a total of required transmission power values calculated for a received pilot signal by the required transmission power total calculation unit of the relay station to a total of the required transmission power values stored in the storage sub-unit, and if the total of the required transmission power values calculated for the pilot signal is smaller, update the identification information and the required transmission power values, which are stored in the storage sub-unit, by use of identification information about respective stations on a transmission path of the pilot signal and required transmission power values thereof.

11. The radio station of any one of claims 5 to 10, wherein

the reception unit receives a pilot signal for a fixed period of time and

the selection unit selects a transmission path having a minimum total of required transmission power values among candidates of the transmission path for the pilot signal received in this fixed period of time.

12. A pilot signal used in a wireless communication system for a multi-hop connection, the system performing signal transmission between a source station, a plurality of relay stations and a destination station, the pilot signal comprising:

identification information about the respective stations on the transmission path of the pilot signal and required transmission power values thereof in order to enable selection of a transmission path having a minimum total of required transmission power values of respective stations.

13. A wireless communication method for a multi-hop connection, which performs signal transmission between a source station, plurality of relay stations and a destination station,

when receiving the pilot signal from the source station directly, the relay station

measures a received SIR of the pilot signal,

calculates a required transmission power value of the source station by use of at least one of a transmission power value of the source station, the measured received SIR and a desired received SIR,

generates a pilot signal including identification information and the required transmission power values of the source station, and

transmits the pilot signal by use of a power prescribed in the transmission power values of the relay station.

14. A wireless communication method for a multi-hop connection, which performs signal transmission between a source station, plurality of relay stations and a destination station,

when receiving the pilot signal from the other relay station, the relay station

measures a received SIR of the pilot signal,

calculates a required transmission power value of the source station by use of at least a transmission power value of the source station,the measured received SIR and a desired received SIR,

specifies a transmission path from the source station to the relay station by use of information included in the received pilot signal,

calculates a total of required transmission power values of respective stations on the transmission path by use of required transmission power values included in a received pilot signal and the required transmission power value calculated for the pilot signal,

selects a transmission path having a minimum total of the required transmission power values among candidates of the specified transmission path,

generates a pilot signal including identification information and the required transmission power values of the source station, and

transmits the pilot signal by use of a power prescribed in the transmission power values of the relay station.

15. A wireless communication method for a multi-hop connection, which performs signal transmission between a source station, plurality of relay stations and a destination station, the destination station

measures a received SIR of the pilot signal,

calculates a required transmission power value in an immediately preceding station, from which the pilot signal is transmitted, by use of a transmission power value of the immediately preceding station, at least one of the measured received SIR and a desired received SIR,

specifies a transmission path from the source station to the destination station by use of information included in the received pilot signal,

calculates a total of required transmission power values of respective stations on the transmission path by use of required transmission power values included in a received pilot signal and the required transmission power value calculated for the pilot signal,

selects a transmission path having a minimum total of the required transmission power values among candidates of the specified transmission path,

transmits a pilot signal including identification information about respective stations on the selected transmission path and required transmission power values thereof.