Methods and arrangements in a telecommunication system for configuring transmission of sounding reference signals

Patent metadata

Field	Value
Publication number	US-9565696-B2
Application number	US-201213370649-A
Country	US
Kind code	B2
Filing date	Feb 10, 2012
Priority date	Feb 22, 2010
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The present invention relates to methods and apparatus for providing a more flexible configuration of sounding reference signal, SRS, transmission. This is achieved by dynamically triggering a mobile terminal to transmit SRS. Thus, embodiments of the invention include a method implemented by a base station in a communications network that semi-statically configures some uplink symbols for periodic SRS transmission and other uplink symbols for aperiodic SRS transmission. The method includes dynamically determining whether an uplink symbol that has been semi-statically configured for aperiodic SRS transmission is to be used by a given mobile terminal at a given time for SRS transmission. The method then further includes signaling a terminal-specific instruction that indicates said determination to the given mobile terminal.

First claim

What is claimed is:

1. A method implemented by a base station in a communications network that semi-statically configures a first plurality of uplink symbols for periodic sounding reference signal, SRS, transmission and a second plurality of uplink symbols, distinct from the first plurality of uplink symbols, for aperiodic SRS transmission, the method comprising:
broadcasting a cell-specific instruction to a plurality of mobile terminals in a cell served by the base station, the cell-specific instruction indicating that an uplink symbol has been semi-statically configured for aperiodic SRS transmission over multiple subsequent subframes;
dynamically determining that a first mobile terminal of the plurality of mobile terminals is to use the uplink symbol for SRS transmission in a given one of the multiple subsequent subframes at least partly based on whether or not the uplink symbol is to be used for data transmission; and
in response to the dynamically determining, signaling a first terminal-specific instruction that is distinct from the cell-specific instruction to the first mobile terminal, the first terminal-specific instruction indicating that the first mobile terminal is to use the uplink symbol for SRS transmission in the given subframe.

2. The method of claim 1 , wherein said signaling comprises signaling the first terminal-specific instruction as downlink control information carried by a physical downlink control channel.

3. The method of claim 1 , wherein the first terminal-specific instruction is at least partially dynamically signaled in an uplink grant.

4. The method of claim 1 , wherein the first terminal-specific instruction is transmitted to the first mobile terminal at a first layer of a communications protocol stack used by the base station and the cell-specific instruction is broadcast to the mobile terminals in the cell at a second layer of said protocol stack, the first layer being lower in the protocol stack than the second layer.

5. The method of claim 1 :
wherein the uplink symbol, due to having been semi-statically configured for aperiodic SRS transmission over the multiple subsequent subframes, is restricted to being used within each of the multiple subsequent subframes to one of:
being used for SRS transmission; and
being left blank.

6. The method of claim 1 , further comprising:
in response to the dynamic determining, signaling a second terminal-specific instruction, distinct from the cell-specific instruction and first terminal-specific instruction, to a second mobile terminal of the plurality of mobile terminals, the second terminal-specific instruction indicating that the second mobile terminal is to leave the uplink symbol blank in the given subframe;
wherein the second mobile terminal is distinct from the first mobile terminal.

7. A method implemented by a mobile terminal in a communications network that semi-statically configures a first plurality of uplink symbols for periodic sounding reference signal, SRS, transmission and a second plurality of uplink symbols, distinct from the first plurality of uplink symbols, for aperiodic SRS transmission, the method comprising:
receiving a cell-specific instruction indicating that an uplink symbol has been semi-statically configured for aperiodic SRS transmission over multiple subsequent subframes;
receiving a terminal-specific instruction, distinct from the cell-specific instruction, that indicates whether the uplink symbol is to be used by the mobile terminal for SRS transmission and not for data transmission in a given one of the multiple subsequent subframes;
determining, based on the received terminal-specific and cell-specific instructions, whether to use the uplink symbol for SRS transmission in the given subframe; and
in the given subframe, dynamically transmitting SRS in the uplink symbol in dependence on the result of said determination.

8. The method of claim 7 :
wherein the terminal-specific instruction indicates one of:
that the uplink symbol is to be used by the mobile terminal for SRS transmission in the given subframe;
that the uplink symbol is to be left blank by the mobile terminal in the given subframe to facilitate use of the uplink symbol for SRS transmission by another mobile terminal in the given subframe; and

wherein the determining, based on the received terminal-specific and cell-specific instructions, whether to use the uplink symbol for SRS transmission in the given subframe comprises determining one of:
to use the uplink symbol for SRS transmission in the given subframe;
to leave the uplink symbol blank in the given subframe.

9. The method of claim 7 , wherein said receiving comprises receiving the terminal-specific instruction as downlink control information carried by a physical downlink control channel.

10. The method of claim 7 , wherein the terminal-specific instruction is at least partially dynamically received in an uplink grant.

11. The method of claim 7 :
wherein the mobile terminal is served by one of a plurality of cells in the communications network;
wherein the cell-specific instruction has been broadcast to at least one other mobile terminal served by said cell and indicates to the at least one other mobile terminal that the uplink symbol has been semi-statically configured for aperiodic SRS transmission over the multiple subsequent subframes.

12. The method of claim 7 , wherein the terminal-specific instruction is received at a first layer of a communications protocol stack used by the mobile terminal and the cell-specific instruction is received at a second layer of said protocol stack, the first layer being lower in the protocol stack than the second layer.

13. The method of claim 7 :
wherein the uplink symbol, due to having been semi-statically configured for aperiodic SRS transmission over the multiple subsequent subframes, is restricted to being used within each of the multiple subsequent subframes to one of:
being used for SRS transmission; and
being left blank;

wherein determining, based on the received terminal-specific and cell-specific instructions, whether to use the uplink symbol of the given subframe for SRS transmission comprises determining that the mobile terminal is to do one of:
use the uplink symbol of the given subframe for SRS transmission; and
leave the uplink symbol of the given subframe blank.

14. A base station for use in a communications network that semi-statically configures a first plurality of uplink symbols for periodic sounding reference signal, SRS, transmission and a second plurality of uplink symbols, distinct from the first plurality of uplink symbols, for aperiodic SRS transmission, the base station comprising:
a processor configured to dynamically determine that a first mobile terminal of a plurality of mobile terminals is to use an uplink symbol for SRS transmission in a given one of multiple subsequent subframes at least partly based on whether or not the uplink symbol is to be used for data transmission; and
a transmitter configured to:
broadcast a cell-specific instruction to the plurality of mobile terminals in a cell served by the base station, the cell-specific instruction indicating that the uplink symbol has been semi-statically configured for aperiodic SRS transmission over the multiple subsequent subframes;
in response to the processor dynamically determining, signal a first terminal-specific instruction that is distinct from the cell-specific instruction to the first mobile terminal, the first terminal-specific instruction indicating that the first mobile terminal is to use the uplink symbol for SRS transmission in the given subframe

Assignees

• Behravan Ali
• Astely David
• Jöngren George
• ERICSSON TELEFON AB L M (publ)

Inventors

• Behravan Ali
• Astely David
• Jöngren George

Classifications

• H04W74/006

  in the downlink, i.e. towards the terminal · CPC title

• H04L5/0092

  Indication of how the channel is divided · CPC title

• H04L25/0224

  using sounding signals · CPC title

• H04L5/005

  of common pilots, i.e. pilots destined for multiple users or terminals · CPC title

• H04L5/0094

  Indication of how sub-channels of the path are allocated · CPC title