METHODS AND NODES FOR RANDOM ACCESS

• US 20140112254A1
• Filed: 06/15/2012
• Published: 04/24/2014
• Est. Priority Date: 06/17/2011
• Status: Active Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lindoff, Bengt, Kazmi, Muhammad, Siomina, Iana
• Application Number:
  US14/124,047
• Publication Number:
  US 20140112254A1
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

The present invention relates to a method in a wireless device for performing a random access to a cell of a wireless network, and to corresponding methods in a radio network node and a positioning node, and the corresponding nodes. The method comprises receiving information from a radio network node comprised in the wireless network, wherein the received information indicates a first and a second random access transmission configuration. The method also comprises selecting one of the first and second random access transmission configurations, and transmitting a random access preamble in accordance with the selected random access transmission configuration.

Claims

1. A method in a wireless device for performing a random access to a cell of a wireless network, the method comprising:

receiving information from a radio network node comprised in the wireless network, wherein the received information indicates a first and a second random access transmission configuration,

selecting one of the first and second random access transmission configurations, and

transmitting a random access preamble in accordance with the selected random access transmission configuration.

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

monitoring to detect a random access response within a first time window when the first random access transmission configuration is selected, and

monitoring to detect the random access response within a second time window when the second random access transmission configuration is selected, wherein the second time window overlaps with at least one low-interference subframe associated with a neighbor cell.

3. The method according to claim 2, further comprising when the random access response is detected within the second time window:

receiving the random access response from the radio network node in at least one of said low interference subframe(s) within the second time window in response to the transmitted random access preamble.

4. The method according to claim 2, wherein the low interference subframe is a downlink almost blank subframe, a blank Multicast-Broadcast Single Frequency Network, MBSFN, subframe, or a subframe of a restricted measurement subframe pattern.

5. The method according to claim 2, further comprising:

receiving information from the radio network node, related to a configuration of the first and the second time window.

6. The method according to claim 1, wherein selecting one of the first and second random access transmission configurations comprises:

receiving a path loss threshold from the radio network node,

measuring a path loss in the cell,

comparing the measured path loss with the received path loss threshold,

selecting one of the first and second random access transmissions based on the comparison.

7. The method according to claim 1 wherein one of the first and second random access transmission configurations is selected based on a capability of the wireless device, and/or a capability of the radio network node, and/or at least one of the following received from the radio network node:

a signal measurement threshold for the cell;

information related to uplink interference for the cell;

an indication whether to use the first or the second random access transmission configuration.

8. The method according to claim 7 wherein the capability of the wireless device and the radio network node is a capability to support a random access procedure comprising:

transmission or reception of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or reception or transmission of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

9. The method according to claim 1, wherein the first random access transmission configuration comprises a first time-frequency resource configured for random access, and the second random access transmission configuration comprises a second time-frequency resource configured for random access, the second time-frequency resource overlapping with a low-interference time-frequency resource associated with the neighbor cell.

10. The method according to claim 9, wherein the low-interference time-frequency resource overlaps with an uplink almost blank subframe used in the neighbor cell.

11. The method according to claim 1, wherein the first random access transmission configuration comprises a first set of preambles configured for random access, and the second random access transmission configuration comprises a second set of preambles configured for random access.

12. The method according to claim 1 wherein the random access preamble is transmitted to the radio network node, or to a neighboring radio network node.

13. The method according to claim 1 further comprising transmitting information to the radio network node related to a capability of the wireless device to support a random access procedure comprising:

transmission of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or reception of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

14. The method according to claim 1, wherein the wireless device and the radio network node communicates via a radio network node serving the wireless device.

15. A method in a radio network node for enabling a wireless device to perform a random access to a cell of a wireless network, the method comprising:

transmitting information to the wireless device, wherein the transmitted information indicates a first and a second random access transmission configuration,

receiving a random access preamble in accordance with one of the first and second random access transmission configurations, and

determining whether the first or the second random access transmission configuration is used based on the received random access preamble.

16. The method according to claim 15, further comprising:

transmitting a random access response in response to the received random access preamble within a first time window, when it is determined that the first random access transmission configuration is used, and

transmitting a random access response in response to the received random access preamble within a second time window, when it is determined that the second random access transmission configuration is used, the second time window overlapping with at least one low-interference subframe associated with the neighbour cell.

17. The method according to claim 16, wherein the random access response is transmitted in a low-interference subframe within the second time window, when it is determined that the second random access transmission configuration is used.

18. The method according to claim 16, wherein the low interference subframe is a downlink almost blank subframe, a blank Multicast-Broadcast Single Frequency Network, MBSFN, subframe, or a subframe of a restricted measurement subframe pattern.

19. The method according to claim 16, further comprising:

transmitting information to the wireless device or to another network node, said information being related to a configuration of the first and the second time window.

20. The method according to claim 15, wherein the first random access transmission configuration comprises a first time-frequency resource configured for random access, and the second random access transmission configuration comprises a second time-frequency resource configured for random access, the second time-frequency resource overlapping with a low-interference time-frequency resource associated with a neighbor cell.

21. The method according to claim 20, wherein the low-interference time-frequency resource overlaps with an uplink almost blank subframe used in a cell.

22. The method according to claim 15, wherein the first random access transmission configuration comprises a first set of preambles configured for random access, and the second random access transmission configuration comprises a second set of preambles configured for random access.

23. The method according to claim 15, further comprising transmitting to the wireless device at least one of a signal measurement threshold for the cell, and information related to uplink interference for the cell.

24. The method according to claim 15, further comprising receiving information from a positioning node, said information indicating whether to use the first or the second random access transmission configuration when performing a positioning measurement, and forwarding the received information to the wireless device.

25. The method according to claim 15, further comprising:

receiving information from a positioning node, said information indicating whether to transmit a random access response within a first or a second time window, the second time window overlapping with at least one low-interference subframe associated with the neighbor cell,

transmitting the random access response in response to the received random access preamble according to the received information,

obtaining a positioning measurement result associated with the random access response, and

transmitting the positioning measurement result to the positioning node.

26. The method according to claim 15, further comprising receiving information related to a capability of the wireless device to support a random access procedure comprising transmission of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell and/or reception of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

27. The method according to claim 26, further comprising forwarding the received information related to the wireless device capability to a network node.

28. The method according to claim 15, further comprising transmitting information to a network node, said information relating to a capability of the radio network node to support a random access procedure comprising:

reception of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or transmission of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

29. The method according to claim 15, wherein the radio network node communicates with the wireless device via a radio network node serving the wireless device.

30. A method in a positioning node for requesting positioning measurements associated with a random access, wherein the positioning node is connected to a radio network node serving a cell to which a wireless device is performing the random access, the method comprising:

transmitting information to the radio network node, wherein the transmitted information indicates whether to use a first or a second random access transmission configuration when performing the positioning measurement, and

receiving a positioning measurement result from the radio network node.

31. The method according to claim 30, wherein the first random access transmission configuration comprises a first time-frequency resource configured for random access, and the second random access transmission configuration comprises a second time-frequency resource configured for random access, the second time-frequency resource overlapping with a low-interference time-frequency resource associated with a neighbor cell.

32. The method according to claim 31, wherein the low-interference time-frequency resource overlaps with an uplink almost blank subframe used in a neighbor cell.

33. The method according to claim 30, wherein the first random access transmission configuration comprises a first set of preambles configured for random access, and the second random access transmission configuration comprises a second set of preambles configured for random access.

34. The method according to claim 30, wherein the transmitted information further indicates whether to use a first or a second time window for a random access response when performing the positioning measurement, wherein the second time window overlaps with at least one low-interference subframe associated with the neighbor cell.

35. A wireless device configured to perform a random access to a cell of a wireless network, the wireless device comprising:

a receiver configured to receive information from a radio network node comprised in the wireless network, wherein the received information indicates a first and a second random access transmission configuration,

a processing circuit configured to select one of the first and second random access transmission configurations, and

a transmitter configured to transmit a random access preamble in accordance with the selected random access transmission configuration.

36. The wireless device according to claim 35, wherein the processing circuit is further configured to:

monitor to detect a random access response within a first time window when the first random access transmission configuration is selected, and

monitor to detect the random access response within a second time window when the second random access transmission configuration is selected, wherein the second time window overlaps with at least one low-interference subframe associated with a neighbor cell.

37. The wireless device according to claim 36, wherein the receiver is further configured to receive the random access response from the radio network node in at least one of said low interference subframe(s) within the second time window in response to the transmitted random access preamble, when the random access response is detected within the second time window.

38. The wireless device according to claim 36, wherein the receiver is further configured to:

receive information from the radio network node, related to a configuration of the first and the second time window.

39. The wireless device according to claim 35, wherein the processing circuit is configured to select one of the first and second random access transmission configurations based on a capability of the wireless device, and/or a capability of the radio network node, and/or at least one of the following received from the radio network node:

a signal measurement threshold for the cell;

information related to uplink interference for the cell;

an indication whether to use the first or the second random access transmission configuration.

40. The wireless device according to claim 35, wherein the receiver is configured to receive a path loss threshold from the radio network node, and the processing circuit is configured to select one of the first and second random access transmission configurations by being configured to:

measure a path loss in the cell,

compare the measured path loss with the received path loss threshold, and

select one of the first and second random access transmissions based on the comparison.

41. The wireless device according to claim 35, wherein the transmitter is further configured to transmit information to the radio network node related to a capability of the wireless device to support a random access procedure comprising:

transmission of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or reception of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

42. A radio network node configured to enable a wireless device to perform a random access to a cell of a wireless network, the radio network node comprising:

a transmitter configured to transmit information to the wireless device, wherein the transmitted information indicates a first and a second random access transmission configuration,

a receiver configured to receive a random access preamble in accordance with one of the first and second random access transmission configurations, and

a processing circuit configured to determine whether the first or the second random access transmission configuration is used, based on the received random access preamble.

43. The radio network node according to claim 42, wherein the transmitter is further configured to:

transmit a random access response in response to the received random access preamble within a first time window, when it is determined that the first random access transmission configuration is used, and

transmit a random access response in response to the received random access preamble within a second time window, when it is determined that the second random access transmission configuration is used, the second time window overlapping with at least one low-interference subframe associated with the neighbour cell.

44. The radio network node according to claim 43, wherein the transmitter is configured to transmit the random access response in a low-interference subframe within the second time window, when it is determined that the second random access transmission configuration is used.

45. The radio network node according to claim 43, wherein the transmitter is further configured to:

transmit information to the wireless device or to another network node, said information being related to a configuration of the first and the second time window.

46. The radio network node according to claim 42, wherein the transmitter is further configured to transmit to the wireless device at least one of a signal measurement threshold for the cell, and information related to uplink interference for the cell.

47. The radio network node according to claim 42, further comprising a communicating unit configured to receive information from a positioning node, said information indicating whether to use the first or the second random access transmission configuration when performing a positioning measurement, and wherein the transmitter is further configured to forward the received information to the wireless device.

48. The radio network node according to claim 42, further comprising:

a communicating unit configured to receive information from a positioning node, said information indicating whether to transmit a random access response within a first or a second time window, the second time window overlapping with at least one low-interference subframe associated with the neighbor cell,

wherein the transmitter is configured to transmit the random access response in response to the received random access preamble according to the received information, the processing circuit is configured to obtain a positioning measurement result associated with the random access response, and the communicating unit is configured to transmit the positioning measurement result to the positioning node.

49. The radio network node according to claim 42, wherein the receiver is further configured to receive information related to a capability of the wireless device to support a random access procedure comprising:

transmission of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or reception of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

50. The radio network node according to claim 42, further comprising a communicating unit configured to transmit information to a network node, said information relating to a capability of the radio network node to support a random access procedure comprising:

reception of random access on a channel overlapping with an uplink low interference time-frequency resource in a neighbor cell, and/or transmission of a random access response on a channel overlapping with a downlink low interference time-frequency resource in a neighbor cell.

51. A positioning node configured to request positioning measurements associated with a random access, wherein the positioning node is connectable to a radio network node serving a cell to which a wireless device is performing the random access, the positioning node comprising a communicating unit configured to:

transmit information to the radio network node, wherein the transmitted information indicates whether to use a first or a second random access transmission configuration when performing the positioning measurement, and

receive a positioning measurement result from the radio network node,

and the positioning node further comprising a processing circuit for handling the received result.

52. The positioning node according to claim 51, wherein the communicating unit is configured to transmit the information further indicating whether to use a first or a second time window for a random access response when performing the positioning measurement, wherein the second time window overlaps with at least one low-interference subframe associated with the neighbor cell.