Radio Network Node User Equipment and Methods Therein

• US 20120314664A1
• Filed: 12/07/2011
• Published: 12/13/2012
• Est. Priority Date: 12/13/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bergman, Johan, Hultell, Johan, Larsson, Erik, Johansson, Niklas A.
• Granted Patent: US 9,241,348 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Embodiments herein relate to a method in a user equipment (10) for requesting access to a radio communications network (1), which user equipment (10) comprises at least two transmit antenna ports. The user equipment (10) obtains one or more random access preambles to be used to access the radio communications network. The user equipment (10) transmits; in case of obtaining one random access preamble, the one random access preamble over the at least two transmit antenna ports. In case of obtaining more than one random access preambles, the user equipment (10) transmits each random access preamble over a separate antenna port out of the at least two transmit antenna ports.

Claims

1-28. -28. (canceled)

29. A method in a user equipment for requesting access to a radio communications network, the user equipment comprising at least two transmit antenna ports, the method comprising:

obtaining one or more random access preambles to be used to access the radio communications network; and

transmitting the one or more random access preambles over the at least two transmit antenna ports by;

transmitting, in the case of obtaining only one random access preamble, the one random access preamble over the at least two transmit antenna ports; and

transmitting, in the case of obtaining more than one random access preambles, each random access preamble over a separate antenna port of the at least two transmit antenna ports.

30. A method according to claim 29, wherein transmitting the one or more access preambles comprises sequentially transmitting the one or more random access preambles over the at least two transmit antenna ports.

31. A method according to claim 30, wherein transmitting the one or more access preambles further comprises:

completing a first random access procedure over a first transmit antenna port out of the at least two transmit antenna ports; and

thereafter, initiating a second random access procedure over a second transmit antenna port out of the at least two transmit antenna ports.

32. A method according to claim 29, wherein transmitting the one or more access preambles comprises simultaneously transmitting the one or more random access preambles over the at least two antenna ports.

33. A method according to claim 29, wherein the one or more random access preambles comprise random access preambles defined in Third Generation Partnership Project TS 25.213 v:

9.2.0 section 4.3.3.

34. A method according to claim 29, wherein obtaining the one or more access preambles comprises selecting a first random access preamble and selecting a second random access preamble orthogonal to the first random access preamble.

35. A method according to claim 29, wherein each transmit antenna port of the at least two transmit antenna ports corresponds to an individual transmit antenna.

36. A method in a radio network node for enabling a user equipment within a radio communications network to request access to the radio communications network, the method comprising:

scanning for a first random access preamble and a second random access preamble from the user equipment;

detecting at least one random access preamble out of the first random access preamble and the second random access preamble; and

transmitting, to the user equipment, an acknowledgement of the at least one random access preamble.

37. A method according to claim 36, wherein transmitting the acknowledgement comprises transmitting the acknowledgement on an acquisition indicator channel.

38. A method according to claim 36, further comprising determining that the user equipment comprises at least two transmit antenna ports based on the detected at least one random access preamble.

39. A method according to claim 36:

wherein detecting at least one random access preamble comprises detecting both the first random access preamble and the second random access preamble; and

wherein transmitting the acknowledgement comprises transmitting separate acknowledgements of the detected first and second random access preambles in separate transmissions.

40. A method according to claim 36:

wherein detecting at least one random access preamble comprises detecting both the first random access preamble and the second random access preamble;

the method further comprising evaluating the detected first and second random access preambles based on a received power of the first and second random access preambles;

wherein transmitting the acknowledgement comprises transmitting feedback information indicating which antenna weights to associate with one of the first and second random access preambles.

41. A method according to claim 40, wherein transmitting the acknowledgement comprises transmitting the acknowledgement only for the random access preamble for which antenna weights are to be used.

42. A method according to claim 40, wherein transmitting the acknowledgement comprises transmitting at least one acknowledgement of the detected first and second random access preambles and transmitting a separate transmission indicating which antenna weights to associate with one of the first and second random access preambles.

43. A user equipment for requesting access to a radio communications network, the user equipment comprising:

at least two transmit antenna ports;

an obtaining circuit configured to obtain one or more random access preambles to be used to access the radio communications network; and

a transmitter configured to transmit the one or more random access preambles over the at least tow transmit antenna ports by;

transmitting, in the case where the obtaining circuit obtains only one random access preamble, the one random access preamble over the at least two transmit antenna ports; and

transmitting, in the case where the obtaining circuit obtains more than one random access preamble, each random access preamble over a separate antenna port of the at least two transmit antenna ports.

44. A user equipment according to claim 43, wherein the transmitter is further configured to sequentially transmit the one or more random access preambles over the at least two transmit antenna ports.

45. A user equipment according to claim 44, wherein the transmitter is further configured to:

complete a first random access procedure over a first transmit antenna port out of the at least two transmit antenna ports; and

thereafter, to initiate a second random access procedure over a second transmit antenna port out of the at least two transmit antenna ports.

46. A user equipment according to claim 43, wherein the transmitter is further configured to simultaneously transmit the one or more random access preambles over the at least two antenna ports.

47. A user equipment according to claim 43, wherein the one or more random access preambles comprise random access preambles defined in Third Generation Partnership Project TS 25.213 v:

9.2.0 section 4.3.3.

48. A user equipment according to claim 43, wherein the obtaining circuit is configured to obtain the one or more random access preambles by selecting a first random access preamble and selecting a second random access preamble orthogonal to the first random access preamble.

49. A user equipment according to claim 43, wherein each transmit antenna port of the at least two transmit antenna ports corresponds to an individual transmit antenna comprised in the user equipment.

50. A radio network node for enabling a user equipment within a radio communications network to request access to the radio communications network, the radio network node comprising:

a scanning circuit configured to scan for a first random access preamble and a second random access preamble from the user equipment;

a detecting circuit configured to detect at least one random access preamble out of the first random access preamble and the second random access preamble; and

a transmitter configured to transmit to the user equipment an acknowledgement of the at least one random access preamble.

51. A radio network node according to claim 50, wherein the transmitter is configured to transmit the acknowledgement on an acquisition indicator channel.

52. A radio network node according to claim 50, further comprising a determining circuit configured to determine that the user equipment comprises at least two transmit antenna ports based on the detected at least one random access preamble.

53. A radio network node according to claim 50:

wherein the detecting circuit is configured to detect both the first random access preamble and the second random access preamble; and

wherein the transmitter is configured to transmit separate acknowledgements of the detected two random access preambles in separate transmissions.

54. A radio network node according to claim 50:

wherein the detecting circuit is configured to detect both the first random access preamble and the second random access preamble;

wherein the radio network node further comprises an evaluating circuit configured to evaluate the detected first and second random access preambles based on a received power of the first and second random access preambles;

wherein the transmitter is configured to transmit feedback information to the user equipment indicating which antenna weights to associate with one of the first and second random access preambles.

55. A radio network node according to claim 54, wherein the transmitter is configured to transmit the acknowledgement only for the random access preamble for which antenna weights are to be used.

56. A radio network node according to claim 54:

wherein the transmitter is configured to transmit at least one acknowledgement of the detected first and second random access preambles; and

wherein the transmitter is further configured to transmit a separate transmission indicating which antenna weights to associate with one of the first and second random access preambles.