Method and arrangement in a wireless communications system

• US 8,724,543 B2
• Filed: 10/18/2007
• Issued: 05/13/2014
• Est. Priority Date: 01/12/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Jngren, George, Gransson, Bo
• Primary Examiner(s): BLANTON, JOHN D
• Application Number:
  US12/522,851
• Publication Number:
  US 20100039990A1
• Time in Patent Office: 2,399 Days
• Field of Search: None
• US Class Current: 370/328
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0482 Adaptive codebooks
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0658 Feedback reduction
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0028 Formatting

Abstract

A method for assisting the adaptation of a signal from a first node (100) to a second node (120) is provided. The first node communicates with the second node in a wireless communication system (110) over a radio link (130). The second node is configured to comprise a codebook, which codebook comprises a set of possible information alternatives used for assisting the adaptation of a signal from the first node to the second node. The second node may select an information alternative from a codebook and send it to the first node to assist the first node how to adapt the signal. The first node is arranged to know a number of subsets, each subset comprising a part of possible information alternatives. The method comprises the steps of sending a configuration request to the second node to restrict the selection of information alternatives to one of the subsets; receiving an information alternative from the second node, which is selected among the at least one subsets configured according to the configuration request.

Claims

1. A method in a base station for adapting a signal to be sent over a radio link from the base station to a User Equipment (UE) in a wireless communication system, wherein the UE is configured to use a codebook comprising a set of possible information alternatives for use by the base station in adapting the signal, and the base station is configured to know a number of subsets of the set of possible information alternatives, each subset comprising a part or all of the codebook, said method comprising:

sending a message to the UE comprising a configuration request that restricts selection of information alternatives in the UE to at least one of the subsets, wherein the configuration request specifies which at least one of the subsets the selection should be restricted to; and

receiving an information alternative from the UE, which information alternative is selected from among the at least one of the subsets according to the configuration request.

2. The method of claim 1, further comprising determining which at least one of the subsets to use for restricting information alternative selection by the UE.

3. The method of claim 2, wherein said determining is based on at least one of a deployment scenario and a reliability analysis, in the base station of the UE reporting to the base station.

4. The method of claim 2, wherein the step of determining is performed by searching for a subset by trying different subsets and selecting the one which maximizes a performance metric.

5. The method of claim 1, wherein the configuration request comprises a bit map where each bit corresponds to a certain information alternative.

6. The method of claim 1, wherein the configuration request comprises a bit map and wherein the value of each bit in the bit map indicates whether to include or exclude a corresponding information alternative in the at least one of the subsets.

7. The method of claim 1, wherein said receiving the information alternative includes receiving the information alternative according to a specific signaling format that comprises certain bits that signal the information alternative.

8. The method of claim 1, wherein the codebook comprises one or several precoders, or comprises one or several precoders and one or several transmission ranks, or combinations thereof.

9. The method of claim 1, wherein the codebook comprises precoder matrices, transmission ranks, modulation choices, transport block sizes, powers and/or channelization codes.

10. The method of claim 1, wherein said receiving the information alternative comprises receiving the information according to a specific signaling format that may be used also for receiving an information alternative selected from at least one other subset that is of a different size than the at least one of the subsets.

11. A method in a User Equipment (UE) for assisting a base station in the adaptation of a signal to be sent over a radio link from the base station to the UE in a wireless communication system, wherein the UE is configured to use a codebook comprising a set of possible information alternatives for use by the base station in adapting the signal, and the base station is configured to know a number of subsets of the set of possible information alternatives, each subset comprising a part or all of the codebook, said method comprising:

receiving a message from the base station comprising a configuration request that restricts selection of information alternatives in the UE to at least one of the subsets, wherein the configuration request specifies which at least one of the subsets the selection should be restricted to;

selecting an information alternative from among the at least one of the subsets specified by the configuration request; and

sending the selected information alternative to the base station.

12. The method of claim 11, wherein the codebook comprises one or several precoders, or comprises one or several precoders and one or several transmission ranks, or combinations thereof, and wherein said selecting an information alternative comprises selecting an element in the subset that optimizes a performance metric.

13. The method of claim 11, wherein the codebook comprises a precoder, or comprises a precoder and a transmission rank.

14. The method of claim 11, wherein the codebook comprises precoder matrices, transmission ranks, modulation choices, transport block sizes, powers and/or channelization codes.

15. The method of claim 11, wherein said sending comprises sending the selected information alternative to the base station using a specific signaling format wherein certain bits signal the information alternative.

16. The method of claim 11, wherein said sending comprises sending the selected information alternative to the base station using a specific signaling format that may be used also for sending an information alternative selected from at least one other subset that is of a different size than the at least one of the subsets.

17. A base station in a wireless communication system that is configured to communicate over a radio link with a User Equipment (UE) in the wireless communication system, wherein the UE is configured to use a codebook comprising a set of possible information alternatives for use by the base station in adapting a signal to be sent from the base station to the UE over the radio link, and wherein the base station is configured to know a number of subsets of the set of possible information alternatives, each subset comprising a part or all of the codebook, said base station comprising:

a sending unit configured to send a message to the UE, the message comprising a configuration request that restricts selection of information alternatives in the UE to at least one of the subsets, wherein the configuration request is configured to specify which at least one of the subsets the selection should be restricted to; and

a receiving unit configured to receive an information alternative from the UE that was selected by the UE from among the at least one of the subsets, as specified by the configuration request.

18. The base station of claim 17, wherein the receiving unit is configured to receive the information alternative according to a specific signaling format, which may be used also for receiving an information alternative selected from at least one other subset that is of a different size than the at least one of the subsets.

19. A User Equipment (UE) in a wireless communication system, the UE configured to communicate with a base station in the wireless communication system over a radio link, wherein the UE uses a codebook comprising a set of possible information alternatives for use by the base station in adapting a signal to be sent from the base station to the UE over the radio link, and wherein the base station is configured to know a number of subsets of the set of possible information alternatives, each subset comprising a part or all of the codebook, said UE comprising:

a receiving unit configured to receive a message from the base station, the message comprising a configuration request that restricts selection of information alternatives in the UE to at least one of the subsets, wherein the configuration request is configured to specify which at least one of the subsets the selection should be restricted to;

a processor circuit executing the functions of;

a configuration unit configured to configure the selection according to the received configuration request;

a selection unit configured to select an information alternative among the configured at least one subsets; and

a sending unit configured to send the selected information alternative to the base station.

20. The UE of claim 19, wherein the processor circuit is configured to execute the sending unit to send the selected information alternative to the base station using a specific signaling format that may be used also for sending an information alternative selected from at least one other subset that is of a different size than the at least one of the subsets.

21. A method, performed at a transmitting node, of adapting a signal to be sent over a radio link from the transmitting node to a receiving node in a wireless communication system, wherein the receiving node is configured to select information alternatives from a codebook comprising a set of possible information alternatives for use by the transmitting node in adapting the signal to be sent over the radio link to the receiving node, the method comprising:

sending a message to the receiving node comprising a configuration request that restricts the selection of information alternatives by the receiving node to one or more subsets of the set of possible information alternatives known to the transmitting node, wherein the configuration request specifies the one or more subsets of the set of possible information alternatives that the selection should be restricted to; and

receiving an information alternative from the receiving node, wherein the information alternative is selected by the receiving node from the one or more subsets of the set of possible information alternatives.

22. The method of claim 21, wherein the configuration request comprises a bit map and wherein the value of each bit in the bit map indicates whether to include or exclude a corresponding information alternative in the one or more subsets specified in the configuration request.

23. The method of claim 21, wherein the configuration request comprises a bit map, and wherein each bit in the bit map corresponds to a given information alternative.

24. The method of claim 21, wherein receiving the information alternative comprises receiving the information alternative according to a specific signaling format, and wherein the specific signaling format may be used also for receiving an information alternative selected from at least one other subset of the set of possible information alternatives having a size that is different than a size of said one or more subsets.

25. A method, performed at a receiving node, of assisting a transmitting node to adapt a signal to be sent over a radio link from the transmitting node to the receiving node in a wireless communication system, wherein the receiving node is configured to select information alternatives from a codebook comprising a set of possible information alternatives for use by the transmitting node in adapting the signal to be sent over the radio link, the method comprising:

receiving a message from the transmitting node comprising a configuration request that restricts the selection of information alternatives by the receiving node to one or more subsets of the set of possible information alternatives known to the transmitting node, wherein the configuration request specifies the one or more subsets of the set of possible information alternatives that the selection should be restricted to;

selecting an information alternative from the one or more subsets indicated by the configuration request; and

sending the selected information alternative to the transmitting node.

26. The method of claim 25, wherein sending the selected information alternative comprises sending the selected information alternative according to a specific signaling format, and wherein the specific signaling format may be used also for sending an information alternative selected from at least one other subset having a size that is different than a size of the one or more subsets indicated by the configuration request.

27. A transmitting node configured to communicate with a receiving node over a radio link in a wireless communication system, wherein the receiving node is configured to make a selection of information alternatives from a codebook comprising a set of possible information alternatives for use by the transmitting node in adapting a signal to be sent over the radio link to the receiving node, the transmitting node comprising:

a sending unit configured to send a message to the receiving node comprising a configuration request that restricts the selection of information alternatives by the receiving node to one or more subsets of the set of possible information alternatives known to the transmitting node, wherein the configuration request is configured to specify the one or more subsets of the set of possible information alternatives that the selection should be restricted to; and

a receiving unit configured to receive an information alternative from the receiving node, wherein the information alternative is selected by the receiving node from the one or more subsets of the set of possible information alternatives.

28. The transmitting node of claim 27, wherein the configuration request is configured to comprise a bit map and wherein the value of each bit in the bit map indicates whether to include or exclude a corresponding information alternative in the one or more subsets specified in the configuration request.

29. The transmitting node of claim 27, wherein the configuration request is configured to comprise a bit map, and wherein each bit in the bit map corresponds to a given information alternative.

30. The transmitting node of claim 27, wherein the receiving unit is configured to receive the information alternative according to a specific signaling format, and wherein the specific signaling format may be used also for receiving an information alternative selected from at least one other subset having a size that is different than a size of said one or more subsets.

31. A receiving node configured to communicate with a transmitting node over a radio link in a wireless communication system, wherein the receiving node is configured to make a selection of information alternatives from a codebook comprising a set of possible information alternatives for use by the transmitting node in adapting a signal to be sent over the radio link, the receiving node comprising:

a receiving unit configured to receive a message from the transmitting node comprising a configuration request that restricts the selection of information alternatives by the receiving node to one or more subsets of the set of possible information alternatives known to the transmitting node, wherein the configuration request is configured to specify the one or more subsets of the set of possible information alternatives that the selection should be restricted to;

a processor circuit configured to execute the functions of a selection unit to select an information alternative from the one or more subsets indicated by the configuration request; and

a sending unit configured to send the selected information alternative to the transmitting node.

32. The receiving node of claim 31, wherein the processor circuit is configured to execute the sending unit to send the selected information alternative according to a specific signaling format, and wherein the specific signaling format may be used also for sending an information alternative selected from at least one other subset having a size that is different than a size of the one or more subsets indicated by the configuration request.