Communication system, communication apparatus, communication method and computer program product

• US 9,001,793 B2
• Filed: 08/10/2010
• Issued: 04/07/2015
• Est. Priority Date: 08/26/2009
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Takano, Hiroaki
• Primary Examiner(s): Beyen, Zewdu A
• Application Number:
  US13/390,612
• Publication Number:
  US 20120176927A1
• Time in Patent Office: 1,701 Days
• Field of Search: 370/329, 370/330, 370/331, 370/332, 370/341
• US Class Current: 370/332
• CPC Class Codes: H04B 7/15507 Relay station based processing for cell extension or control of coverage area, network planning with network coordinated processing with regard to cell extension H04W16/26; network topologies using dedicated repeater stations H04W84/047; terminal devices adapted for relaying to or from an other terminal H04W88/04
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

A relay node (or relay station) assists in providing asymmetric communications with a mobile station. When resources are less than ideal for providing a direct uplink or downlink with the mobile station to a first base station, the relay station is employed to provide an uplink or downlink to a second base station. The mobile station may still maintain a direct downlink/uplink to the first base station when adequate resources are present. To assist in resource coordination the first and second base stations share scheduling information for the mobile station. This approach allows a second base station to server as a surrogate base station for a first base station, when inadequate resources are available for a direct uplink or downlink to the mobile station. The relay node makes it possible for the mobile station to maintain the uplink (or downlink) with the second base station, while remaining assigned to the first base station.

Claims

1. A mobile communication system comprising:

a first base station that services a first coverage area and establishes a first link with a mobile station within said first coverage area, said first link being one of an uplink and a downlink; and

a second base station that services a second coverage area and establishes a second link with said mobile station via a relay node within said second coverage area, said second link being an other of said uplink and said downlink, wherein

said first base station determines whether a communication quality of said first link between said mobile station and said first base station is below a predetermined level,

said first base station transmits a first instruction to said mobile station when said communication quality of said first link is below said predetermined level and said first link is an uplink, said first instruction to disconnect said first link with first said base station, establish an uplink with said second base station and maintain said second link with said second base station, said second link being a downlink, and

said first base station transmits a second instruction to said mobile station when said communication quality of said first link is below said predetermined level and said first link is a downlink, said second instruction to disconnect said first link with said first base station, establish a downlink with said second base station and maintain said second link with said second base station, said second link being an uplink.

2. The mobile communication system of claim 1, wherein said first coverage area includes

an inner region where wireless resources are dedicated for use by said first base station, and

an outer region where said wireless resources are shared by said first base station and said second base station.

3. The mobile communication system of claim 1, wherein said mobile station communicates with said first base station via said first link and communicates with said second base station via said second link by using Coordination Multiple Point transmission and reception (CoMP).

4. The mobile communication system of claim 1, wherein

said first base station adjusts said predetermined level to account for a communication quality of said second link between said mobile station and said second base station, and

said first base station maintains said first link when the communication quality of said second link is lower than said communication quality of said first link and said communication quality of said first link is equal to or greater than said predetermined level.

5. The mobile communication system of claim 1, wherein said first base station schedules wireless resources, said wireless resources including intercell interference coordination using fractional frequency repetition that combines one-cell frequency repetition and multi-cell frequency repetition.

6. The mobile communication system of claim 1, wherein

said first base station determines a relative location of said mobile station according to at least one of signal strength, GPS reception and signal delay, and

said first base station and said second base station coordinate scheduling of wireless resources for a mobile station located in said first coverage area.

7. A mobile station for use in a wireless communications system having a first base station that services a first coverage area and a second base station that services a second coverage area, said mobile station comprising:

a controller;

a scheduling information storage device that is accessible to said controller and stores information including a scheduling table indicating wireless resources for communication with the first base station and the second base station; and

a transmitter, wherein

when said mobile station is within said first coverage area, said controller controls said transmitter to establish a first link with said first base station, said first link being one of an uplink and a downlink, and establish a second link with said second base station via a relay node within said second coverage area, said second link being an other of said uplink and said downlink,

when a communication quality of said first link is below a predetermined level and when said first link is an uplink, said transmitter receives a first instruction from said first base station, the first instruction to disconnect said first link from said first base station, establish an uplink with said second base station and maintain said second link with said second base station, said second link being a downlink, and

when a communication quality of said first link is below a predetermined level and said second link is a downlink, said transmitter receives a second instruction from said first base station, the second instruction to disconnect said first link from said first base station, establish a downlink with said second base station and maintain said second link with said second base station, said second link being an uplink.

8. The mobile station of claim 7, wherein the first coverage area includes

an inner region where said wireless resources are dedicated for use by said first base station, and

an outer region where said wireless resources are shared between said first base station and said second base station, wherein

said mobile station includes a GPS receiver that informs said first base station of a position of said mobile station.

9. The mobile station of claim 7, wherein said mobile station communicates with said first base station via said first link and communicates with said second base station via said second link by using Coordination Multiple Point transmission and reception (CoMP).

10. The mobile station of claim 7, wherein said controller maintains said first link with said first base station when said communication quality of said second link is lower than said communication quality of said first link and said communication quality of said first link equal to or greater than said predetermined level.

11. The mobile station of claim 7, wherein said information in the scheduling information storage device includes scheduling information based on fractional frequency repetition that combines one-cell frequency repetition and multi-cell frequency repetition.

12. A base station for a wireless mobile communication system, said base station comprising:

a transmitter that provides wireless coverage over a first coverage area and establishes a link with a mobile station within said first coverage area, said link being one of an uplink and a downlink, and said first coverage area abutting a second coverage area provided by a second base station; and

a relay mode decision circuit that

determines, when said mobile station is within said first coverage area, whether a communication quality of said link between said mobile station and said base station is below said predetermined level,

controls the transmitter to transmit a first instruction to said mobile station when said communication quality of said link is below said predetermined level and said link is an uplink, said first instruction to disconnect said link with said base station, establish an uplink with said second base station and maintain a second link between said mobile station and said second base station, said second link being a downlink, and

controls the transmitter to transmit a second instruction to said mobile station when said communication quality of said first link is below said predetermined level and said first link is a downlink, said first instruction to disconnect said first link with said base station, establish a downlink with said second base station and maintain said second link between said mobile station and said second base station, said second link being an uplink.

13. The base station of claim 12, wherein said first coverage area includes

an inner region where wireless resources are dedicated for use by said base station, and

an outer region where said wireless resources are shared between said base station and said second base station.

14. The base station of claim 12, wherein said mobile station communicates with said base station via said link and communicates with said second base station via said second link by using Coordination Multiple Point transmission and reception (CoMP).

15. The base station of claim 12, wherein said relay mode decision circuit adjusts said predetermined level to account for a communication quality of said second link between said mobile station and said second base station, and

said transmitter maintains said link when the communication quality of said second link is lower than said communication quality of said link and said communication quality of said link is equal to or greater than said predetermined level.

16. The base station of claim 15, wherein said relay mode decision circuit determines a relative location of said mobile station according to at least one of signal strength, GPS reception and signal delay, and

said relay mode decision circuit controls said transmitter to coordinate scheduling of wireless resources for the mobile station in said first coverage area with the second base station.

17. A method for conducting wireless communications in a mobile communication system, comprising:

establishing, by a first base station that services a first coverage area, a first link with a mobile station within said first coverage area, said first link being one of an uplink and a downlink;

establishing, by a second base station that services a second coverage area, a second link with said mobile station via a relay node within said second coverage area, said second link being an other of said uplink and said downlink;

determining, by said first base station, whether a communication quality of the first link is below a predetermined threshold;

transmitting, by said first base station, a first instruction to said mobile station when said communication quality of said first link is below said predetermined level and said first link is an uplink, said first instruction to disconnect said first link with first said base station, establish an uplink with said second base station and maintain said second link with said second base station, said second link being a downlink; and

transmitting, by said first base station, a second instruction to said mobile station when said communication quality of said first link is below said predetermined level and said first link is a downlink, said second instruction to disconnect said first link with said first base station, establish a downlink with said second base station and maintain said second link with said second base station, said second link being an uplink.

18. The communication method of claim 17, wherein Coordination Multiple Point transmission and reception (CoMP) is used to establish the second link with the mobile station.

19. The communication method of claim 17, wherein said first coverage area includes

an inner region where wireless resources are dedicated for use by said first base station, and

an outer region where said wireless resources are shared by said first base station and said second base station.

20. The communication method of claim 17, further comprising:

adjusting, by said first base station, said predetermined level to account for a communication quality of said second link between said mobile station and said second base station; and

maintaining, by said first base station, said first link when the communication quality of said second link is lower than said communication quality of said first link and said communication quality of said first link is equal to or greater than said predetermined level.