SPACE-TIME CHANNEL SOUNDING IN WIRELESS NETWORK

• US 20140369435A1
• Filed: 06/13/2013
• Published: 12/18/2014
• Est. Priority Date: 06/13/2013
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kneckt, Jarkko Lauri Sakari, Alanen, Olli, Huovinen, Toni
• Granted Patent: US 9,337,908 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0643 Feedback on request
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

A method, apparatus, and computer program for carrying out channel sounding are provided. Said method comprises: causing, by an apparatus, transmission of a request for space-time channel sounding to at least one unassociated access node; receiving, in the apparatus as a multi-antenna transmission and in response to said request, at least one message comprising space-time sounding information from at least one unassociated access node; determining, by the apparatus, at least one parameter describing space-time channel quality from the received space-time sounding information; and causing, by the apparatus, transmission of the at least one determined parameter to an associated access node or causing selection of an unassociated access node for further communication based at least partly on the determined at least one parameter.

Claims

1. A method comprising:

causing, by an apparatus, transmission of a request for space-time channel sounding to at least one unassociated access node;

receiving, in the apparatus as a multi-antenna transmission and in response to said request, at least one message comprising space-time sounding information from at least one unassociated access node;

determining, by the apparatus, at least one parameter describing space-time channel quality from the received space-time sounding information; and

causing, by the apparatus, transmission of the at least one determined parameter to an associated access node or causing selection of an unassociated access node for further communication based at least partly on the determined at least one parameter.

2. The method of claim 1, wherein the request for the space-time channel sounding comprises at least one of a probe request and a space-time channel sounding measurement indication.

3. The method of claim 1, wherein the apparatus is a terminal device associated to the associated access node.

4. The method of claim 1, further comprising receiving, from the at least one unassociated access node before the reception of the at least one message comprising the space-time sounding information, a response to said request via omnidirectional transmission, the response serving as a channel sounding announcement.

5. The method of claim 1, wherein the at least one message comprises a probe response or a message received after receiving a probe response.

6. The method of claim 1, wherein the at least one message comprises a null data packet frame.

7. The method of claim 1, wherein the request comprises a request to recommend an access node for an association, the method further comprising in the apparatus:

receiving a frame comprising an information element indicating an identifier of an unassociated access node recommended for association.

8. The method of claim 1, wherein the request comprises a notification that the apparatus will send a second message comprising space-time sounding information, the method further comprising in the apparatus:

causing transmission of the second message after the request.

9. The method of claim 8, wherein the second message is a null data packet.

10. The method of claim 1, wherein the at least one parameter comprises at least one of the following:

a rank of the space-time channel specifying a number or uncorrelated space-time streams between the apparatus and the at least one unassociated access node, a metric representing received signal strength for one or more space-time stream, an estimate representing deterioration of space-time channel quality.

11. An apparatus comprising:

at least one processor; and

at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to;

cause transmission of a request for space-time channel sounding to at least one unassociated access node;

receive, as a multi-antenna transmission and in response to said request, at least one message comprising space-time sounding information from at least one unassociated access node;

determine at least one parameter describing space-time channel quality from the received space-time sounding information; and

cause transmission of the at least one determined parameter to an associated access node or cause selection of an unassociated access node for further communication based at least partly on the determined at least one parameter.

12. The apparatus of claim 11, wherein the request for the space-time channel sounding comprises at least one of a probe request and a space-time channel sounding measurement indication.

13. The apparatus of claim 11, wherein the apparatus is a terminal device associated to the associated access node.

14. The apparatus of claim 11, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive, from the at least one unassociated access node before the reception of the at least one message comprising the space-time sounding information, a response to said request via omnidirectional transmission, the response serving as a channel sounding announcement.

15. The apparatus of claim 11, wherein the at least one message comprises a probe response or a message received after receiving a probe response.

16. The apparatus of claim 11, wherein the at least one message comprises a null data packet frame.

17. The apparatus of claim 11, wherein the request comprises a request to recommend an access node for an association, and wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive a frame comprising an information element indicating an identifier of an unassociated access node recommended for association.

18. The apparatus of claim 11, wherein the request comprises a notification that the apparatus will send a second message comprising space-time sounding information, and wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to cause transmission of the second message after the request.

19. The apparatus of claim 18, wherein the second message is a null data packet.

20. The apparatus of claim 11, wherein the at least one parameter comprises at least one of the following:

a rank of the space-time channel specifying a number or uncorrelated space-time streams between the apparatus and the at least one unassociated access node, a metric representing received signal strength for one or more space-time stream, an estimate representing deterioration of space-time channel quality.

21. The apparatus of claim 11, further comprising radio interface components providing the apparatus with radio communication capability.

22. A computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a computer process comprising:

causing transmission of a request for space-time channel sounding to at least one unassociated access node;

receiving, as a multi-antenna transmission and in response to said request, at least one message comprising space-time sounding information from at least one unassociated access node;

determining at least one parameter describing space-time channel quality from the received space-time sounding information; and

causing transmission of the at least one determined parameter to an associated access node or cause selection of an unassociated access node for further communication based at least partly on the determined at least one parameter.