Granted Patent B2

US 8,792,369 · App. 13/098,810 · Granted Jul 29, 2014

Abstract

Claims (63)

1. A method, comprising:

performing at least one uplink direction delay spread measurement of a radio resource transmitted by a mobile node;

selecting, at a base station, an uplink direction cyclic prefix length for at least one uplink radio resource based on the at least one uplink direction delay spread measurement;

indicating the selected uplink direction cyclic prefix length to the mobile node;

receiving an uplink direction signal from the mobile node with the uplink direction cyclic prefix length selected; and

activating use of mobile node specific cycle prefixes in response to detecting that a traffic distribution between mobile nodes supporting mobile node specific cycle prefixes and mobile nodes not supporting mobile node specific cyclic prefixes exceeds a predefined threshold.

2. The method according to claim 1 , the method further comprising:

removing at least one cyclic prefix from the uplink signal received to obtain at least one useful uplink symbol.

3. The method according to claim 1 , the method further comprising:

receiving, at the base station, an indication whether the mobile node supports mobile node specific cyclic prefixes.

4. The method according to claim 1 , the method further comprising:

selecting a downlink direction cyclic prefix length for at least one downlink radio resource;

forming a downlink direction cyclic prefix of the downlink direction cyclic prefix length selected from a useful downlink symbol;

adding the downlink direction cyclic prefix in front of the useful downlink symbol; and

transmitting a signal comprising the downlink direction cyclic prefix and the useful downlink symbol to the mobile node.

5. The method according to claim 1 , the method further comprising:

transmitting a radio resource to the mobile node to enable the measuring of a downlink direction delay spread at the mobile node.

6. The method according to claim 5 , the method further comprising:

receiving from the mobile node an indication of the downlink direction delay spread measured by the mobile node; and

selecting a downlink direction cyclic prefix length based on the downlink direction delay spread.

7. The method according to claim 5 , the method further comprising:

receiving from the mobile node an indication of a downlink direction cyclic prefix length.

8. The method according to claim 6 , the method further comprising:

indicating the downlink direction cyclic prefix length selected to the mobile node.

9. The method according to claim 1 , the method further comprising:

detecting at the base station a change in antenna configuration; and

activating measuring of the delay spread in response to the change in antenna configuration.

10. The method according to claim 1 , where the base station is a central unit of a coordinated multipoint transmission and reception base station set.

11. A base station, comprising:

at least one radio frequency circuit configured to perform at least one uplink direction delay spread measurement of a radio resource transmitted by a mobile node and to receive an uplink direction signal from the mobile node with an uplink direction cyclic prefix length selected; and

at least one processor configured to:

select the uplink direction cyclic prefix length for at least one uplink radio resource based on the at least one uplink direction delay spread measurement and to indicate the uplink direction cyclic prefix length selected to the mobile node, and

activating use of mobile node specific cycle prefixes in response to detecting that a traffic distribution between mobile nodes supporting mobile node specific cycle prefixes and mobile nodes not supporting mobile node specific cyclic prefixes exceeds a predefined threshold.

12. A system, comprising:

a first base station receiver configured to measure a first uplink direction delay spread of a radio resource transmitted from a mobile node, to report the first uplink direction delay spread to a base station node, and to receive an uplink direction signal from the mobile node with the uplink direction cyclic prefix length selected;

a second base station receiver configured to measure a second uplink direction delay spread of a radio resource transmitted from a mobile node, to report the second uplink direction delay spread to a base station node, and to receive an uplink direction signal from the mobile node with the uplink direction cyclic prefix length selected; and

a base station node configured to:

select a maximum uplink direction delay spread among the first uplink direction delay spread and the second uplink direction delay spread, to select an uplink direction cyclic prefix length for at least one uplink radio resource based on the maximum uplink direction delay spread and to indicate the uplink direction cyclic prefix length selected to the mobile node, and

activating use of mobile node specific cycle prefixes in response to detecting that a traffic distribution between mobile nodes supporting mobile node specific cycle prefixes and mobile nodes not supporting mobile node specific cyclic prefixes exceeds a predefined threshold.

13. A computer readable memory storing a computer program comprising code adapted to cause the following when executed on a data-processing system:

performing at least one uplink direction delay spread measurement of a radio resource transmitted by a mobile node;

selecting, at a base station, an uplink direction cyclic prefix length for at least one uplink radio resource based on the at least one uplink direction delay spread measurement;

indicating the selected uplink direction cyclic prefix length to the mobile node;

receiving an uplink direction signal from the mobile node with the uplink direction cyclic prefix length selected; and

activating use of mobile node specific cycle prefixes in response to detecting that a traffic distribution between mobile nodes supporting mobile node specific cycle prefixes and mobile nodes not supporting mobile node specific cyclic prefixes exceeds a predefined threshold.

14. The computer readable memory according to claim 13 , wherein the computer program is further adapted to cause:

removing at least one cyclic prefix from the uplink signal received to obtain at least one useful uplink symbol.

15. The computer readable memory according to claim 13 , wherein the computer program is further adapted to cause:

receiving, at the base station, an indication whether the mobile node supports mobile node specific cyclic prefixes.

16. The computer readable memory according to claim 13 , wherein the computer program is further adapted to cause:

selecting a downlink direction cyclic prefix length for at least one downlink radio resource;

forming a downlink direction cyclic prefix of the downlink direction cyclic prefix length selected from a useful downlink symbol;

adding the downlink direction cyclic prefix in front of the useful downlink symbol; and

transmitting a signal comprising the downlink direction cyclic prefix and the useful downlink symbol to the mobile node.

17. The computer readable memory according to claim 13 , wherein the computer program is further adapted to cause:

transmitting a radio resource to the mobile node to enable the measuring of a downlink direction delay spread at the mobile node.

18. The computer readable memory according to claim 17 , wherein the computer program is further adapted to cause:

receiving from the mobile node an indication of the downlink direction delay spread measured by the mobile node; and

selecting a downlink direction cyclic prefix length based on the downlink direction delay spread.

19. The computer readable memory according to claim 17 , wherein the computer program is further adapted to cause:

receiving from the mobile node an indication of a downlink direction cyclic prefix length.

20. The computer readable memory according to claim 18 , wherein the computer program is further adapted to cause:

indicating the downlink direction cyclic prefix length selected to the mobile node.

Assignments (10)