METHODS AND DEVICES FOR SPATIAL CODING

• US 20110164697A1
• Filed: 09/12/2008
• Published: 07/07/2011
• Est. Priority Date: 09/12/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kazmi, Muhammad, Liao, Jingyi
• Granted Patent: US 8,717,947 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04L 1/0625 Transmitter arrangements

Abstract

Embodiments of the invention relates to a method in a controller node for distributing code text of a joint spatial coding in a communications network. The communications network comprises at least two communication nodes each comprising at least one transmit antenna. The method comprises to joint spatial code (12, S11) a symbol resulting in at least a first code text and a second code text. Then, the method comprises to group (T4, S12) the transmit antennas in the communications network into at least a first transmit antenna group and a second transmit antenna group based on the location of coverage area of the transmit antennas. Finally, the method comprises to distribute (T6) the first code text to the first transmit antenna group and the second code text to the second transmit antenna group. The invention is particularly useful for transmission in Multimedia Broadcast Single Frequency Network (MBSFN) comprising of communication nodes equipped with unequal number of transmit antennas. Embodiments also relates to a controller node, a second communication node, a user equipment and methods therein.

Claims

1. A method in a controller node for distributing code text of a joint spatial coding in a communications network comprising at least two communication nodes each comprising at least one transmit antenna comprising:

joint spatial coding (T2, S11) a symbol resulting in at least a first code text and a second code text,

grouping (T4, S12) the transmit antennas in the communications network into at least a first transmit antenna group and a second transmit antenna group based on a location of coverage area of the transmit antennas, and

distributing (T6) the first code text to the first transmit antenna group and the second code text to the second transmit antenna group.

2. A method according to claim 1, wherein the grouping (T4, S12) is based on the location of coverage area of the transmit antennas so that the distribution of the different code texts is arranged to distribute the code texts to user equipments in a way that a user equipment within the communications network receives both the code texts.

3. A method according to claim 1, wherein the grouping (T4, S12) is arranged so that the first code text and the second code text are distributed to transmit antennas in alternating sites.

4. A method according to claim 1, wherein at least two communication nodes in the communications network comprise a unequal number of transmit antennas.

5. A method according to claim 1, wherein regrouping (T10, S13) of the transmit antennas comprises receiving (T8) feedback from a user equipment indicating selected transmit antenna group which is then used to regroup the transmit antennas.

6. A method according to claim 5, wherein the regrouping (T10, S13) is based on statistics of feedback from a plurality of user equipments.

7. A method according to claim 1, wherein the grouping (T4, S12) is also based on predetermined capacity of the nodes, stored within the controller node.

8. A method according to claim 1, wherein the location of the coverage area of every node in the communications network is retrieved (T1) during initial setup of the controller node, updated periodically, and/or when a new node is added to the communications network.

9. A method according to claim 1, wherein the communications network comprises a Multimedia Broadcast Single Frequency Network and/or the joint spatial coding comprises Space Time Block Coding, Per Antenna Rate control or the like.

10. A controller node (10) arranged, in a communications network comprising at least two communication nodes each comprising at least one transmit antenna, to distribute code texts of a joint spatial coding to the nodes, wherein the controller node (10) comprises a control unit (101) arranged to joint spatial code a symbol into at least a first code text and a second code text and to group the transmit antennas in the communications network into at least a first transmit antenna group and a second transmit antenna group based on a location of coverage area of the transmit antennas, and a network interface (109) configured to distribute the first code text to the first transmit antenna group and the second code text to the second transmit antenna group.

11. A controller node (10) according to claim 10, wherein the control unit (101) is arranged to group the transmit antennas based on the location of coverage area of the transmit antennas so that the distribution of the different code texts is arranged in a way such that a user equipment within the communications network receives both the code texts.

12. A controller node (10) according to claim 10, wherein at least two communication nodes in the communications network comprise a unequal number of transmit antennas.

13. A controller node (10) according to claim 10, wherein the network interface (109) is further arranged to receive feedback from a user equipment, the feedback comprises data of a selected transmit antenna group and the control unit (101) is arranged to use the feedback to regroup the transmit antennas in the communications network.

14. A controller node (10) according to claim 13, wherein the control unit (101) is arranged to regroup the transmit antennas in the communications network based on statistics of feedback from a plurality of user equipments.

15. A controller node (10) according to claim 10, wherein the control unit (101) is arranged to group the transmit antennas based also on predetermined capacity of the nodes, stored in a memory (107) within the controller node.

16. A controller node (10) according to claim 10, wherein the controller node is arranged to retrieve location of the coverage of the transmit antennas in the communications network during initial setup of the controller node, during periodically updating, and/or when a new node is added to the communications network.

17. A controller node (10) according to claim 10, wherein the communications network comprises a Multimedia Broadcast Single Frequency Network, and/or the joint spatial coding comprises Space Time Block Coding, Per Antenna Rate control and/or the like.

18. A controller node (10) according to claim 10, wherein the control unit (101) is arranged to group the transmit antennas so that the first code text and the second code text are distributed to transmit antennas in alternating sites.

19. A controller node (10) according to claim 10, comprising a base station, base station controller, eNodeB, or/and a combination thereof.

20. A method in a second communication node within a communications network comprising at least two communication nodes each comprising at least one transmit antenna, the method comprises the steps of:

receiving (V2) from a controller node a first code text of a joint spatial coding based on a location of coverage area of the transmit antennas, and

distributing (V6) the first code text to a user equipment within a cell of a first transmit antenna of the second communication node.

21. A method according to claim 20, further comprising the step of setting up (V4) the second communication node in an operational state to apply the first code text to a transmission of data on a radio channel from the first transmit antenna within the cell of the first transmit antenna and transmitting the data.

22. A method according to claim 20, further comprising the step of receiving (V8) feedback from a user equipment regarding the first code text wherein the feedback indicates a selection of the first code text, and

forwarding (V10) the feedback to the controller node of the communications network.

23. A second communication node (20) arranged, in a communications network comprising at least two communication nodes each comprising at least one transmit antenna, to set up operational setting of joint spatial coding within the communications network, comprising a network interface (209) arranged to receive from a controller node a first code text of a joint spatial coding based on a location of coverage of the transmit antennas, and a control unit (201) arranged to distribute through a first transmitting arrangement (210) the first code text to a user equipment within a cell of the first transmitting arrangement (210).

24. A second communication node (20) according to claim 23, wherein the control unit (201) is further arranged to apply the first code text to a transmission of data on a radio channel from the first transmitting arrangement (210) within the cell of the first transmitting arrangement (210) and to transmit the data over the first transmitting arrangement (210).

25. A second communication node (20) according to claim 23, further comprising a receiving arrangement (210) configured to receive feedback from a user equipment regarding the first code text wherein the feedback indicates a selection of the first code text and the control unit (201) is arranged to forward the feedback to the controller node in the network over the network interface (209).

26. A second communication node (20) according to claim 23, wherein the second communication node comprises a base station, and/or the like.

27. A method in a user equipment within a communications network comprising at least two communication nodes each comprising at least one transmit antenna for selecting an operational setup using a code text of a joint spatial coding comprising the steps of:

receiving (R2) a first signal with a first code text from a second communication node,

receiving (R4) a second signal with a second code text from a third communication node,

evaluating (R6) the first and second signal,

selecting (R8) code text based on the evaluation, and

transmitting (R10) feedback to the second communication node indicating the selection.

28. A method according to claim 27, wherein the step of selecting code text is based on evaluating the first and second signals to determine a preferred precoding weighting vector, and/or its associated codebook index.

29. A user equipment (40) arranged, in a communications network comprising at least two communication nodes each comprising at least one transmit antenna, to select an operational setup using a code text of a joint spatial coding, the user equipment comprises a receiving arrangement (403) configured to receive a first signal with a first code text from a second communication node and a second signal with a second code text from a third communication node, a control unit (401) arranged to evaluate the signals and based on the evaluation to select code text and to create feedback data indicating the selection, and a transmitting arrangement (405) configured to transmit the feedback data to the second communication node.

30. A user equipment (40) according to claim 29, wherein the control unit (401) is arranged to select the code text based on the evaluation to find a preferred precoding weighting vector, and/or its associated codebook index.