Methods and Apparatuses for Handling Reference Signals in a Cellular Network

• US 20130039285A1
• Filed: 12/22/2011
• Published: 02/14/2013
• Est. Priority Date: 08/12/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sorrentino, Stefano
• Granted Patent: US 8,750,230 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04W 72/51 based on terminal or device properties

Abstract

Methods and apparatuses for enabling a configured demodulation reference signal to be transmitted from a User Equipment, UE, (202) when served by a base station (200) in a cellular network. The base station sends (2:3) at least one configuration parameter to the UE, which indicates a UE-specific base sequence and/or a UE-specific cyclic shift hopping pattern assigned (2:2) to the UE. The UE then uses the configuration parameters to generate (2:4) and transmit (2:5) the demodulation reference signal based on the UE-specific base sequence and UE-specific cyclic shift hopping pattern. Thereby, orthogonality can be achieved between the transmitted demodulation reference signal and any demodulation reference signals transmitted by other UEs, by using separate UE-specific base sequences and/or UE-specific cyclic shift hopping patterns.

Claims

1-30. -30. (canceled)

31. A method in a base station for enabling a user equipment to transmit a configured demodulation reference signal when being served by the base station, the method comprising:

assigning at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern to the user equipment, and

sending at least one configuration parameter to the user equipment, said configuration parameters indicating the assigned at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern, to enable the user equipment to use said configuration parameters to generate and transmit the demodulation reference signal based on the at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern.

32. The method according to claim 31, wherein said at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern substitutes at least one of a default cell-specific base sequence and a default cell-specific cyclic shift hopping pattern configured in the user equipment.

33. The method according to claim 31, wherein said at least one configuration parameter comprises at least one of a UE-specific base sequence parameter Δ

_SS,UE which the user equipment can use for determining said UE-specific base sequence and a UE-specific cyclic shift hopping parameter Δ

_CS,UE which the user equipment can use for determining said UE-specific cyclic shift hopping pattern.

34. The method according to claim 33, wherein the UE-specific base sequence is defined by a modified sequence shift pattern f_SS,UE^PUSCH for a PUSCH channel and the UE-specific cyclic shift hopping pattern is defined by a modified cyclic shift random generator initialization parameter c_initi,UE, and wherein said modified sequence shift pattern f_SS,UE^PUSCH can be determined based on the UE-specific base sequence parameter Δ

_SS,UE, and said modified cyclic shift random generator initialization parameter c_initi,UE can be determined based on the UE-specific cyclic shift hopping parameter Δ

_CS,UE.

35. The method according to claim 34, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS+Δ

_SS,UE)mod 30, and

f_SS,UE+floor(N_ID^cell/30)*2⁵+(f_SS^PUSCH+Δ

_CS,UE)mod 30,

where Δ

_SS is a predefined cell-specific parameter, f_SS^PUSCH is a default sequence shift pattern for a PUSCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

36. The method according to claim 34, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)* 2⁵+Δ

_CS,UE,

where f_SS^PUCCH is a default sequence shift pattern for a PUCCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

37. The method according to claim 31, wherein Multiple-Input-Multiple Output, MIMO, is employed for receiving at least two data stream layers from the user equipment, and at least one of said UE-specific base sequence and said UE-specific cyclic shift hopping pattern is assigned to each of the at least two data stream layers.

38. The method according to claim 31, wherein the at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern are assigned to a group of user equipments connected to the base station.

39. A base station adapted to enable a user equipment to transmit a configured demodulation reference signal when being served by the base station, the base station comprising:

a configuration circuit adapted to assign at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern to the user equipment, and

a transceiver circuit adapted to send at least one configuration parameter to the user equipment, said configuration parameters indicating the assigned at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern, to enable the user equipment to use said configuration parameters to generate and transmit the demodulation reference signal based on the at least one of said UE-specific base sequence and UE-specific cyclic shift hopping pattern.

40. The base station according to claim 39, wherein said at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern substitutes at least one of a default cell-specific base sequence and a default cell-specific cyclic shift hopping pattern configured in the user equipment.

41. The base station according to claim 39, wherein said at least one configuration parameter comprises at least one of a UE-specific base sequence parameter Δ

_SS,UE which the user equipment can use for determining said UE-specific base sequence and a UE-specific cyclic shift hopping parameter Δ

_CS,UE which the user equipment can use for determining said UE-specific cyclic shift hopping pattern.

42. The base station according to claim 41, wherein the UE-specific base sequence is defined by a modified sequence shift pattern f_SS,UE^PUSCH for a PUSCH channel and the UE-specific cyclic shift hopping pattern is defined by a modified cyclic shift random generator initialization parameter c_initi,UE, and wherein said modified sequence shift pattern f_SS,UE^PUSCH can be determined based on the UE-specific base sequence parameter Δ

_SS,UE and said modified cyclic shift random generator initialization parameter c_initi,UE can be determined based on the UE-specific cyclic shift hopping parameter Δ

_CS,UE.

43. The base station according to claim 42, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+(f_SS^PUSCHΔ

_CS,UE)mod 30,

where Δ

_SS is a predefined cell-specific parameter, f_SS^PUSCH is a default sequence shift pattern for a PUSCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

44. The base station according to claim 42, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+Δ

_CS,UE,

where f_SS^PUCCH is a default sequence shift pattern for a PUCCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

45. The base station according to claim 39, wherein Multiple-Input-Multiple Output, MIMO, is employed for receiving at least two data stream layers from the user equipment, and at least one of said UE-specific base sequence and said UE-specific cyclic shift hopping pattern is assigned to each of the at least two data stream layers.

46. The base station according to claim 39, wherein the at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern are assigned to a group of user equipments connected to the base station.

47. A method in a user equipment for creating a demodulation reference signal for transmission when being served by a base station, the method comprising:

receiving at least one configuration parameter from the base station, said configuration parameters indicating at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern,

generating the demodulation reference signal based on the at least one of the UE-specific base sequence and the UE-specific cyclic shift hopping pattern, and

transmitting the generated demodulation reference signal.

48. The method according to claim 47, wherein said at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern substitutes at least one of a default cell-specific base sequence and a default cell-specific cyclic shift hopping pattern configured in the UE.

49. The method according to claim 47, wherein said at least one configuration parameter comprises at least one of a UE-specific base sequence parameter Δ

_SS,UE which is used for determining said UE-specific base sequence and a UE-specific cyclic shift hopping parameter Δ

_CS,UE which is used for determining said UE-specific cyclic shift hopping pattern.

50. The method according to claim 49, wherein the UE-specific base sequence is defined by a modified sequence shift pattern f_SS,UE^PUSCH for a PUSCH channel and the UE-specific cyclic shift hopping pattern is defined by a modified cyclic shift random generator initialization parameter c_initi,UE, and wherein said modified sequence shift pattern f_SS,UE^PUSCH is determined based on the UE-specific base sequence parameter Δ

_SS,UE, and said modified cyclic shift random generator initialization parameter c_initi,UE is determined based on the UE-specific cyclic shift hopping parameter Δ

_CS,UE.

51. The method according to claim 50, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+(f_SS^PUSCH+Δ

_CS,UE)mod 30,

where Δ

_SS is a predefined cell-specific parameter, f_SS^PUSCH is a default sequence shift pattern for a PUSCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

52. The method according to claim 50, wherein the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE are determined as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+Δ

_CS,UE,

where f_SS^PUCCH is a default sequence shift pattern for a PUCCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

53. The method according to claim 47, wherein Multiple-Input-Multiple Output, MIMO, is employed for sending at least two data stream layers to the base station, and at least one of said UE-specific base sequence and said UE-specific cyclic shift hopping pattern has been assigned to each of the at least two data stream layers.

54. A user equipment adapted to create a demodulation reference signal for transmission when being served by a base station, the user equipment comprising:

a transceiver circuit adapted to receive at least one configuration parameter from the base station, said configuration parameters indicating at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern, and

a control circuit adapted to generate the demodulation reference signal according to the at least one of the UE-specific base sequence and the UE-specific cyclic shift hopping pattern,

wherein the transceiver circuit is further adapted to transmit the generated demodulation reference signal.

55. The user equipment according to claim 54, wherein said at least one of a UE-specific base sequence and a UE-specific cyclic shift hopping pattern substitutes at least one of a default cell-specific base sequence and a default cell-specific cyclic shift hopping pattern configured in the user equipment.

56. The user equipment according to claim 54, wherein said at least one configuration parameter comprises at least one of a UE-specific base sequence parameter Δ

_SS,UE which is used for determining said UE-specific base sequence and a UE-specific cyclic shift hopping parameter Δ

_CS,UE which is used for determining said UE-specific cyclic shift hopping pattern.

57. The user equipment according to claim 56, wherein the UE-specific base sequence is defined by a modified sequence shift pattern f_SS,UE^PUSCH for a PUSCH channel and the UE-specific cyclic shift hopping pattern is defined by a modified cyclic shift random generator initialization parameter c_initi,UE, and wherein the control circuit is further adapted to determine said modified sequence shift pattern f_SS,UE^PUSCH based on the UE-specific base sequence parameter Δ

_SS,UE, and to determine said modified cyclic shift random generator initialization parameter c_initi,UE based on the UE-specific cyclic shift hopping parameter Δ

_SS,UE.

58. The user equipment according to claim 57, wherein the control circuit is further adapted to determine the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+(f_SS^PUSCH+Δ

_CS,UE)mod 30,

where Δ

_SS is a predefined cell-specific parameter, f_SS^PUSCH is a default sequence shift pattern for a PUSCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_CS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

59. The user equipment according to claim 57, wherein the control circuit is further adapted to determine the modified sequence shift pattern f_SS,UE^PUSCH and the modified cyclic shift random generator initialization parameter c_initi,UE as:

f_SS,UE^PUSCH=(f_SS^PUCCH+Δ

_SS,UE)mod 30, and

c_initi,UE=floor(N_ID^cell/30)*2⁵+Δ

_CS,UE,

where f_SS^PUCCH is a default sequence shift pattern for a PUCCH channel, 30 is the number of available base sequences, each of the configuration parameters Δ

_SS,UE and Δ

_SS,UE has a range of 0 . . . 29, and N_ID^cell is the cell ID for a cell N.

60. The user equipment according to claim 54, wherein Multiple-Input-Multiple Output, MIMO, is employed for sending at least two data stream layers to the base station, and at least one of said UE-specific base sequence and said UE-specific cyclic shift hopping pattern has been assigned to each of the at least two data stream layers.