Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
HYBRID RECONFIGURATION METHODS AND APPARATUS FOR TDD ADAPTATION
Document Type and Number:
WIPO Patent Application WO/2014/110692
Kind Code:
A1
Abstract:
Methods, systems, and devices are described for reconfiguring a user equipment (UE) to operate in a reconfigured TDD UL-DL configuration. An initial uplink- downlink (UL-DL) configuration for TDD communication may be provided for communication between a base station and a UE. One or more subframes within each frame transmitted using the initial UL-DL configuration may be identified as flexible subframes. The identification of flexible subframes may permit the identification of timing for HARQ transmissions that does not change when a reconfiguration takes place. A different UL-DL configuration may be transmitted to the UE, in which at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The different UL-DL configuration may be transmitted by; for example, a pseudo-uplink grant to the UE, which indicates that the UE is to reconfigure one or more flexible subframes from uplink to downlink transmission.

Inventors:
WEI CHAO (US)
WANG NENG (US)
FENG MINGHAI (US)
HOU JILEI (US)
Application Number:
PCT/CN2013/000050
Publication Date:
July 24, 2014
Filing Date:
January 17, 2013
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
QUALCOMM INC (US)
WEI CHAO (US)
WANG NENG (US)
FENG MINGHAI (US)
HOU JILEI (US)
International Classes:
H04W72/04
Domestic Patent References:
WO2012149673A12012-11-08
Foreign References:
CN102740477A2012-10-17
EP2498419A22012-09-12
CN102076031A2011-05-25
Attorney, Agent or Firm:
LEE AND LI - LEAVEN IPR AGENCY LTD. (Tower W1 Oriental Plaza,1 East Chang An Avenue,East, Beijing 8, CN)
Download PDF:
Claims:
CLAIMS

1. A method of wireless communication performed by a base station in time-division duplex (TDD) communication with a user equipment (UE), comprising:

determining art initial uplink-downlink (UL-DL) configuration for TDD communication with the UE;

identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes;

determining a different UL-DL configuration is to be used for TDD

communication with the UE, the different UL-DL configuration comprising at. least one Dexibie subframe that is to be changed from an uplink subframe to a downlink subframe; and transmitting a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe,

2. The method of claim 1, wherein the reconfiguration message comprises physical layer signaling to the UE.

3. The method of claim 1 , wherein the reconfiguration message comprises a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in a subsequent frame.

4. The method of claim 1 , wherein hybrid automatic retransmission request (HARQ) acknowledgment timing is unchanged between the initial UL-DL configuration and the different UL-DL configuration.

5. The method of claim 1, wherein the initial UL-DL configuration comprises a maximum number of uplink subframes within each frame.

6. The method of claim 5 , further comprising:

determining an uplink hybrid automatic retransmission request

(HARQ)acknowledgment position within the subframes based on the UL-DL configuration of the maximum number of uplink subframes. 7. The method of claim 5, wherein the maximum number of uplink subframes is transmitted in a system information block (SIB),

8. The method of claim 5, wherein, the ini tial UL-DL configuration further comprises a minimum number of uplink subirames within each frame. 9. The method of claim 8, further comprising:

determining a downlink HARQ acknowledgment position within the subirames based on UL-DL configuration of the minim am number of uplink subirames. 10. The method of claim 8, wherein the minimum number of uplink subirames are transmitted using a first bitmap identifying the minimum number of uplink subirames. 1. 1. The method of claim 8, wherein the minimum number of uplink subirames are transmitted using a configuration index thai identifies minimum uplink subirames in a semi-static set of different minimum uplink subirames. 12, The method of claim 10, wherein the maximum number of uplink subirames are transmitted using a second bitmap identifying the maximum number of uplink subirames. 13. The method of claim 12, wherein the at least one flexible subframe is determined based on the first and second bitmaps. 14. The method of claim 8, wherein the minimum number of uplink subfram.es are transmitted using radio resource control (RRC) signaling with the UB. 15, The method of claim 1, further comprising:

transmitting the initial UL-DL configuration to the IJE. 16. The method of claim 15, wherein the initial UL-DL configuration is transmitted in one system information block (SIB). 17. The method of claim 15, wherein the reconfiguration message comprises one or more of a radio resource control (RRC) message that identifies the flexible subi ames that are to be reconfigured. 18, The method of claim. L wherein, the flexible subfram.es are initially configured as uplink subframes. 1 . A method of wireless communication performed by a base station in time-division duplex (TDD) coimmmieation with a user equipment (UE), comprising:

txansmitting an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE; and

transmitting a pseudo-uplink grant to the UE to reconfigure the UL-DL configuration to a different UL-DL configuration. 20. The method of claim 19. wherein the pseudo-uplink grant comprises an invalid resource block allocation for at least one flexible subframe, 21 , The method of claim 20, wherein the invalid resource block allocation comprises a resource indication value (RIV) that exceeds a maximum value of an RIV for aa uplink grant. 22. The method of claim 1 , wherein the pseudo-uplink grant comprises a first pseudo-uplink grant for a first, of the flexible subframes, and wherein the method further comprise transmitting a second pseudo-uplink grant for a second of the flexible subframes. 23. A method of wireless communication performed by a user equipment (UE) in. lime-division duplex (TDD) communication with a base station, comprising:

receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station;

identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes; and

receiving a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe in the subsequent frame.

24. The method of claim 23, wherein receiving a reconfiguration message comprises receiving physical layer signaling at the UE.

3 25. The method of claim 23, wherein the reconfiguration message comprises a pseudo-uplink grant having an invalid resource block allocation for the at least

5 one flexible subframe.

1 26. The method of claim 25, wherein the invalid resource block allocation comprises a resource indication value (RiV) that exceeds a maximum value of an RIV for an

3 uplink grant.

J 27, The method of claim 25, wherein receiving the reconfiguration

2 message comprises receiving a second pseudo-uplink grant for a second of the flexible

3 subframes. 28. The method of claim 23, wherein HARQ acknowledgment timing is

5 unchanged between the initial UL-DL configuration and the reconfigured UL-DL

6 configuration.

1 29. The method of claim 23. wherein the initial UL-DL configuration

2 comprises a maximum number of uplink subframes within each frame.

1 30. The method of claim 29, further comprising;

2 determining an uplink HARQ acknowledgment position within the subframes

3 based on the UL-DL configuration of the maximum number of uplink subframes.

1. 3 1.. The method of claim 29, wherein the maximum number of uplink subframes is received in a system information block (SIB).

1 32. The method of claim 29, wherein the initial. UL-DL configuration

2 further comprises a minimum number of uplink subframes within each frame.

1 33, The method of claim 32, further comprising;

2 determining a downlink HARQ acknowledgment position within the

3 subframes based on the UL-DL confi uration of the minimum number of uplink subframes.

1 34, The method of claim 32, wherein the minimum number of uplink

subframes are received using a bitmap identifying the minimum number of uplink subframes. 35, The method of claim 32, wherein the mmimum number of uplink subframes are transmitted ositig a configuration index that identifies minimum uplink subframes in a semi-static set of different minimum uplink subframes. 36. The method of claim 23, further comprising:

receiving the initial UL-DL configuration from the base station. 37. The method of claim 36, wherein the initial UL-DL configuration is received in one system information block (SIB). 38, The method of claim 23, wherein the flexible subframes are initially configured as uplink subframes, 39, The method of claim 23, wherein the reconfiguration message

comprises one or .more of radio resource control ( RC) messaging that identifies the flexible subframes that are to be reconfigured. 40. A method of wireless communication performed by a user equipment (UE) in time-division duplex (TDD) communication with a base station, comprising:

receiving an initial uplink-downlink (UL-DL) configuration for TDD

communication with the base station; and

receiving a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration. 41 . The method of claim 40, wherein the pseudo-u link grant comprises an invalid resource block allocation for the at least one flexible subframe. 42. The method of claim 41 , wherein the invalid resource block allocation comprises a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant.

43. The method of claim 40, wherein the pseudo-uplink grant comprises a first pseudo-uplink grant for a first of the flexible subframes, and wherein the method further comprises receiving a second pseudo-uplink grant for a second of the flexible subframes. 44, A wireless communication base station apparatus in time-division duple (TDD) communication with a user equipment (UE), comprising;

at least one processor configured to:

determine an initial uplink-downlink (UL-DL) configuration for TDD communication with the UE;

identify one or more subiranies withi each frame transmitted using the initial UL-DL configuration as flexible subiranies;

determine a different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible sub rarae that is to be changed from an uplink subframe to a downlink subirame; and

transmit a reconfiguration message to the UE, indicating that the at. least one flexible subframe is to be changed from an uplink subirame to a downlink subframe; and

a memory coupled with the at least one processor. 45. The apparatus of claim 44, wherein the reconfiguration message comprises physical layer signaling to the UE, 46, The apparatus of claim 44, wherein the reconfiguration message comprises a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in the subsequent frame. 47. The apparatus of claim 44, wherein the processor is further configured to transmit the initial UL-DL configuration to the UE, 48. The apparatus of claim 47. wherein the initial UL-DL configuration is transmitted in one system information block (SIB), 49. The apparatus of c laim 47, wherein the reconfiguration message comprises one or more of radio resource control. (RRC) message that identifies the flexible subframes that are to be reconfigured. 50, A wireless communication base station apparatus in time-diviskm duple (TDD) communication with a user equipment (UE), comprising;

at least one processor configured to:

transmit an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE; and

transmit a pseudo-uplink grant to the UE to reconfigure the UL-DL configuration to a different UL-DL configuration; and

a memory coupled with the at least one processor. 51. The apparatus of claim 50, wherein the pseudo-uplink grant comprises an invalid resource block allocation for at least one flexible subframe. 52. The apparatus of claim 5 , wherein the in valid resource block allocation comprises a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant. 53. The apparatus of claim 50, wherein the pseudo-uplink grant comprises a first pseudo-uplink grant for a first of the flexible subframes, and wherein the at least one processor is further configured to transmit a second pseudo-uplink grant for a second of the flexible subframes, 54. A. wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex {TDD} uplink-downlink (UL-DL) configurations, comprising:

at least one processor configured to*

receive an initial uplmk-dowrdink (UL-DL) configuration for TDD communication with the base station;

identify one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes; and

receive a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe; and

a memory coupled with the at least one processor. 1 55, The apparat us of claim 54, wherein the reconfiguration message comprises physical layer signaling received at the UE. 56. The apparatus of claim 54, wherein the reconfiguration message comprises a pseudo-uplink grant having an invalid resource block allocation for the at least one flexible subirame.

1 57, The apparatus of claim 56, wherein the invalid resource block

allocation comprises a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant.

I. 58. The apparatus of claim 54, wherein the initial UL-DL configuration is received in a system information block (SIB).

1 59. The apparatus of claim 54, wherein the reconfiguration message

comprises one or more of radio resource control (RRC) messaging that identifies the flexible sub-frames that are to be reconfigured.

1 60. A wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations, comprising:

at. least, one processor configured to:

receive an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station; and

receive a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration; and

a memory coupled with the at least one processor.

3 61. The apparatus of claim 60, wherein the pseudo-uplink grant comprises an invalid resource block allocation for at least one flexible subirame.

I 62. The apparatus of claim 61 , wherein the invalid resource block

allocation comprises a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant.

63. The apparatus of claim 60, wherein the pseudo-uplink grant comprises a first pseudo-upfink grant for a first of the flexible subframes, and wherein the processor is further configured to receive a second pseudo-uplink gran t for a second of the flexible subframes, 64. A wireless communication base station apparatus in time-division duplex (TDD) communication with a user equipment (UE), comprising:

means for determining an initial uplink-downlink (UL-DL) configuration for TDD communication with the UE

means for identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes;

means for determining different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe; and

means for transmitting a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. 65, The apparatus of claim 64, wherein the reconfiguration message comprises physical layer signaling to the UE. 66, The apparatus of claim 64, wherein the reconfiguration message comprises a pseudo-uplink grant for the at ieast one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in a subsequent frame. 67. The apparatus of claim 64, wherein the initial UL-DL configuration is transmitted in a system information block (SIB). 68. The apparatus of c laim 64, wherein the reconfiguration message comprises one or more of radio resource control. (RRC) message that identifies the flexible subframes that are to be reconfigured. 69, A wireless communication base station apparatus in time-division duple (TDD) communication with a user equipment (UE), comprising;

means for transmitting an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE: and

means for transmitting a pseudo-uplink grant to the UE to reconfigure the UL- DL configuration to a different UL-DL configuration. 70, The apparatus of claim 69, wherein the pseudo-uplink grant comprises an invalid resource block allocation for the at least one flexible subframe. 7.1. A wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex (TDD) up! ink-down Sink (UL-DL) configurations, comprising;

means for receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with a base station;

means for identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes; and

means for receiving a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subtrame, 72, The apparatus of claim 71 , wherein the reconfiguration message comprises physical layer signaling received at the UE. 73. The apparatus of claim 71, wherein the reconfiguration message comprises a pseudo-uplink grant having an invalid resource block allocation for the at least. one flexible subirame. 74. A. wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations, comprising;

means for receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station; and

means for receiving a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration. 75, The apparatus of claim 74, wherein the pseudo-uplink grant comprises an invalid resource block allocatio for the at least one flexible subframe.

76. The apparatus of claim 75, wherein the invalid resource block

allocation comprises a resource indicatio value (RIV) that exceeds a maximum, value of an RIV for an uplink grant.

77. A computer program product for wireless communications by a base station configured for multiple concurrent time-division duplex (TDD) uplink-downlink (UL- DL) configurations, comprising:

a non-transitory computer-readable medium comprising code for:

determining an initial uplink-downlink (UL-DL) configuration for TDD communication with the UE;

identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes;

determining a different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe; and

transmitting a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe.

78. The computer program product of claim 77, wherein the reconfiguration message comprises physical layer signaling to the UE.

79. The computer program product, of claim 77, wherein the reconfiguration message comprises a pseudo-uplink grant for the at least, one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in the subsequent frame.

80. The computer program product of claim 77, wherein, the reconfiguration message comprises one or more of radio resource control (RRC) message that identifies the flexible subframes that are to be reconfigured. 1 , A computer program product for wireless communications by a base station configured for multiple concurrent time-division duplex (TDD) uplink-downlink (UL- DL) configurations, comprising:

a non-transitory computer-readable medium comprising code for:

transmitting an initial uplink-downlink ( UL-DL) configuration for TDD communication to the U E: and

transmitting a pseudo-uplink, grant to the UE to reconfigure the U L-DL configuration to a different UL-DL configuration.

82, The computer program product of claim 81 , wherein the pseudo-uplink grant comprises an invalid resource block allocation for at least one .flexible subframe . 83. A. computer program product for wireless communications by a user equipment (UE) configured to operate using one of multiple time-di vision duplex (TDD) uplink-downlink ("UL-DL) configurations, comprising:

a non-transitory computer-readable medium comprising code for:

receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with a base station;

identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes; and

eceiving a reconfiguration message indicating mat the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. 84. The computer program product of claim 83, wherein the reconfiguration message comprises a pseudo-uplink grant having an invalid resource block. allocation for the at least, one flexible subframe. 85, A computer program product for wireless communications by a user equipment (UE) configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations, comprising:

a non-transitory computer-readable medium comprising code for: receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station; and

receiving a pseudo-uplink grant to reconfigure the UL-DL

configuration to a different UL-DL configuration. 86. The computer program product of claim 85, wherein the pseudo-uplink grant comprises an invalid resource block allocation for at least one flexible subframe. 87, The computer program product of claim 85, wherein the invalid resource block allocation comprises a resource indication value (RI V) that exceeds a maximum value of an RIV for an uplink grant

Description:
HYBRID RECONFIGURATION METHODS AND APPARATUS FOR TDD

ADAPTATION

BACKGROUND

{00011 The following relaies generally to wireless communication, and more specifically to establishing wireless communications with base stations having preferred signal transmission configurations. Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power), Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDM.A) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems. Additionally, some systems may operate using time -division duplex (TDD), in which a single carrier frequency is used for both uplink and downlink

communications, and some systems may operate using frequency-division duplex (FDD), in which separate carrier frequencies are used for uplink and downlink communications.

10002] In systems that operate using TDD, different formats may be used in which uplink and downlink communications may be asymmetric. TDD formats include transmission of frames of data, each including a number of different subframes in which different subframes may be uplink or downl ink subframes. Reconfiguration of TDD formats may be

implemented based on data traffic patterns of the particular system, in order to provide additional uplink or downlink data capacity to users of the system.

SUMMARY

100 31 The described features generall relate to one or more improved systems, methods, and/or apparatuses for reconfiguring a user equipment (UE) t operate in a reconfigured TDD UL-DL configuration. An initial uplink-downlink (UL-DL) configuration for TDD

communication may be provided for communication between a base station and a UE. One or more subframes withi each frame transmitted using the initial UL-DL configuration may be identified as flexible subframes. The identification of flexible subframes may permit the identification of timing for HARQ transmissions that does not change when a econfiguration takes place. A different UL-DL configuration may be transmitted to the UE, in which at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The different UL-DL configuration may be transmitted by, for example, a pseiido- uplink grant to the UE or RRC signaling to the UE, which may indicate that the UE is to reconfigure one or more suhframes for uplink or downlink transmission.

(0004) In one aspect; a method of wireless communication performed by a base station in time-division duplex. (TDD) communication with a user equipment (UE) is provided. The method general ly includes determining an initial uplink-downlink (UL-DL) configuration for TDD communication with the UE, identifying one or more suhframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, determining a different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe, and transmitting a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message may include, for example, physical, layer signaling to the UE, and/or a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in subsequent frame, in some embodiments, hybrid automatic retransmission request (HARQ) acknowledgment timing i unchanged between the initial UL-DL configuration and the different UL-DL configuration, i some embodiments, the initial UL-DL configuration may include a maximum number of uplink suhframes within each frame,

10005] In some embodiments, the method may also include determining a uplink hybrid automatic retransmission request (HARQ Acknowledgment position within the subframes based on the UL-DL configuration of the maximum number of uplink subframes. The maximum number of uplink subframes may be transmitted, for example, in a system information block (SIB), The initial UL-DL configuration may also include a minimum number of uplink subframes within each frame. In some embodiments, the method may also include determining a downlink HARQ acknowledgment position within the subframes based on UL-DL configuration of the minimum number of uplink subframes. The minimum number of uplink subframes may be transmitted, for example, using a first, bitmap identifying the minimum number of uplink subframes or a configuration index that identifies minimum uplink subframes in a semi-static set. of di fferent minimum uplink subframes. The maximum number of uplink subframes may be transmitted using a second bitma identifying the maximum number of uplink subframes or using a second configuration index that identifies the maximum, number of subframes, in some embodiments, at least one flexible subframe is determined based, on the first and second bitmaps or first and second configuration indices, in some embodiments, the minimum number of upl ink subframes are transmitted using radio resource control (RRC) signaling with the UE.

{0006] In some embodiments, the method may further include transmitting the initial UL- DL configuration to the UE. The initial UL-DL configuration may be transmitted, for example, in one system information block (SI B). The reconfiguration message may include, for example, one or more of a radio resource control (RRC) message that, identifies the flexible subframes that are to be reconfigured. In some embodiments, the flexible subframes are initially configured, as uplink subframes,

{0007] In another aspect, a method of wireless communication performed by a base station in time-division duple (TDD) com unication with a user equipment (UE) is provided. The method generally includes transmitting an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE, and transmitting a pseudo-uplink grant, to the UE to reconfigure the UL-DL configuration to different UL-DL configuration. The pseudo-uplink grant may include, for example, an invalid resource block allocation for at least one flexible subframe. Such an invalid resource block allocation ma include a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant, for example. In some embodimeetns, a pseudo-uplink grant may include a first, pseudo-uplink grant for a first of the flexible subframes, and wherein the method further comprises transmitting a second pseudo- uplink grant for a second of the flexible subframes.

(0008) In another aspect, a method of wireless communication performed by a user equipment (UE) in time-division duplex (TDD) communication with a base station is provided. The method generally includes receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station, identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, and. receiving a reconfiguration message indicating that the at least one flexible subirame is to be changed from an uplink sub frame to a downlink subirame in the subsequent frame. The receiving a reconfiguration message may include, for example, receiving physical layer signaling at the UE. The reconfiguration message may include, for example, a pseudo-uplink grant having an invalid resource block allocatio for the at least one flexible subirame. Such an invalid resource block allocation may include, for example, a resource indication value (RIV) that exceeds a maximum value of an R1V for an uplink grant.

Receiving the reconfiguration message may include, in some embodiments, receiving a second pseudo-uplink grant for a second of the .flexible subframes.

10009] In some embodiments, HARQ acknowledgment timing may be unchanged between the initial ' UL-DL configuration and the reconfigured UL-DL configuration. In some embodiments, the initial UL-DL configuration may include a maximum number of upli nk, subframes within each frame. Determining an uplink HARQ acknowledgment position within the subframes may be based on the UL-DL con figuration of the maximum number of uplink subframes, in some embodiments. The maximum number of uplink subframes may be received, for example, in a system information block (SIB). The initial UL-DL configuration may also include a minimum number of uplink subframes within each frame. The method may further include, in some embodiments, determining a downlink HARQ acknowledgment position within the subframes based on the UL-DL configuration of the minimum number of uplink subframes. The minimum number of uplink, subframes may be received, for example, using a bitmap identifying the minimum number of uplink subframes, or using a

configuration index that identifies minimum uplink subframes in a semi-static set of different minimum uplink su frames.

|0010] In some embodiments, the method may further include receiving the initial UL-DL configuration from the base station. The initial UL-DL configuration may be received, for example, in one system information block. (SIB). The flexible subframes may initially be configured as uplink subframes, in some embodiments. The reconfiguration message may include one or more radio resource control (RRC) messages that identifies the flexible subframes that are to be reconfigured. 0011] In another aspect, a method of wireless communication performed by a user equipment (UE) in time-division duplex (TDD) communication with a base station is provided. The method generally includes receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station, and receiving a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration. The pseudo-uplink grant may include, for example, an invalid resource block allocation for the at least one flexible subframe. The invalid resource block allocation may include, for example, a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant, in some embodiments, the pseudo-uplink grant may include a first pseudo-uplink grant for a first of the flexible subfranies, and wherein the method may further include receiving a second pseudo-uplink, grant for a second of the flexible subframes.

1 012 j In another aspect, a wireless communication base station apparatus in time-division duplex (TDD) communication with a user equipment (UE) is provided. The apparatus generally includes at least one processor and a memory coupled with the processor. The processor may be configured to determine an initial uplink-downliiik (UL-DL) configuration for TDD communication with the UE, identify one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, determine a different UL-DL configuration is to be used for TDD communication with the UE, the different UL- DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe, and transmit a reconfiguration message t the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message may include physical layer signaling to the UE, and/or may include a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in the subsequent, frame. The reconfiguration message may include one or more of radio resource control (RRC) message that, identifies the flexible subframes that, are to be reconfigured, for example,

10013} In another aspect, a wireless communication base station apparatus in time-division duplex (TDD) communication with a user equipment (UE) is provided. The apparatus generally includes at least one processor and a memory coupled with the at least one processor. The processor may he configured to transmit an Initial uplink-downlink (UL-DL) configuration for TDD communication to the UE, and transmit a pseudo-uplink grant to the UE to reconfigure the UL-DL configuration to a different UL-DL configuration. The pseudo- uplink grant may include, for example an invalid resource block allocation for at least one flexible subframe, and the invalid resource block allocation may include a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant, in some embodiments.

(ΘΘ14) in another aspect, a wireless communication user equipment CUE) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The apparatus generally includes at least one processor and a memory coupled with the processor. The processor may be configured to receive an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station, identify one or more subirames within each frame transmitted using the initial UL- DL configuration as flexible subirames, and receive a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message ma include physical layer signaling received at the UE and/or may include a pseudo-upiink grant having an invalid resource block allocation for the at least one flexible subframe, for example. 0015] In another aspect, a wireless communication user equipment (U E) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The apparatus generally includes at least one processor and a memory coupled with the processor. The processor may be configured to receive an initial uplink-down! ink (UL-DL) configuration for TDD communication with the base station, and receive a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration. The pseudo-uplink grant may include an invalid resource block allocation for at least one flexible subframe, which may include a resource indication value (RIV) that exceeds a maximu value of an. RIV for an uplink grant, for example. The pseudo-uplink grant may include a first pseudo-uplink grant for a first of the flexible

subirames, and the processor may be further configured to receive a second pseudo-upiink grant, for a second of the flexible subframes, in some embodiments.

(0016} in another aspect, a wireless communication base station apparatus in time-division duplex (TDD) communication with a user equipment (UE). The apparatus generally includes means for determining an initial uplink-downlink (UL-DL) configuration for TDD

communication with the UE, means for identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, means for determining a different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe, and means for transmitting a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message may include, for example, physical layer signaling to the UE and/or a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in a subsequent frame. The initial UL-DL configuration may be transmitted in a system information block (SIB), for example. In some embodiments, the reconfiguration message may include one or more of radio resource control ( RC) message that identifies the flexible subframes that are to be reconfigured.

{0017} In another aspect, a wireless communication base station apparatus in time-division duplex (TDD) communication with a user equipment (UE) is provided. The apparatus generally includes means for transmitting an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE, and means for transmitting a pseudo-uplink grant to the UE to reconfigure the U L-DL configuration to a different UL-DL configuration. The pseudo- uplink grant may include an invalid resource block allocation for the at least one flexible subframe, for example,

{0018] In another aspect, wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The apparatus generally includes means for receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with a base station, means for identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, and means for .receiving a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message may include physical layer signaling received at the UE and/or a pseudo-uplink grant having an invalid resource block allocation for the at least one flexible subframe, for example.

10019] In another aspect, a wireless communication user equipment (UE) apparatus configured to operate using one of multiple time-division duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The apparatus generally includes means for receiving an initial uplink-downlink (UL-DL) co figuration for TDD communication with the base station, and means for receiving a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL configuration. The pseudo-uplink grant may include, for example, an invalid resource block allocation for the at least one flexible subfranie, which may include a resource indication value (RIV) thai exceeds a maximum value of an RIV for an uplink grant.

|0020| In another aspect, a computer program product for wireless communications by a base station configured for multiple concurrent time-division duplex (TDD) uplink -downlink (UL-DL) configurations is provided. The computer program product generally comprises a non-transitory computer-readable medium that includes code for determining an initial uplink-downlink (UL-DL) configuration for TDD communication with the UE, identifying one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes, determining a different UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subfranie that is to be changed from an uplink subfranie to a downlink subframe, and transmitting a reconfiguration message to the UE, indicating that the at least one flexible sub-frame is to be changed from an uplink subframe to a downlink subframe. The

reconfiguration message may include physical layer signaling to the UE and/or a pseudo- uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in. the subsequent frame, for example. In some

embodiments, the reconfiguration message may include one or more of radio resource control (RRC) message that identifies the flexible subframes that are to be reconfigured,

|βί)21] In another aspect, a computer program product for wireless communications by a base station configured for multiple concurrent time-division duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The computer program product generally comprises a non-transitory computer-readable medium that includes code for transmitting an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE, and transmitting a pseudo-uplink grant to the UE to reconfigure the UL-DL configuration to a different UL- DL configuration. The pseudo-uplink grant may include an invalid resource block allocation for at least one flexible subframe, for example.

(0022f in another aspect, a computer program product for wireless communications by a user equipmen (UE) configured to operate using one of multiple time-division duplex (TDD) upliMk-dowi ink (UL-DL) configurations is provided. The computer program product generally includes a non-transitory computer-readable medium that includes code for receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with a base station, identifying one or more subfraraes within eac frame transmitted using the initial UL-DL configuration as flexible subframes, and receiving a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe. The reconfiguration message may include a pseudo-uplink grant having an invalid resource block allocation for the at least one flexible subframe, for example, {0023 j In another aspect, a computer program product for wireless communications by a user equipment (UE) configured to operate using one of multiple time-di vision duplex (TDD) uplink-downlink (UL-DL) configurations is provided. The computer program product generall includes a non-transitory computer-readable medium that includes code for receiving an initial uplink-downlink (UL-DL) configuration for TDD communication with the base station, and receiving a pseudo-uplink grant to reconfigure the UL-DL configuration to a different UL-DL confi uration. The pseudo-uplink grant may include an invalid resource block allocation for at least one flexible subframe, and the invalid resource block allocation comprises a resource indication value f IV) that exceeds a maximum value of an R.1V for an uplink grant, for example.! 0024 j Further scope of the applicability of the

described methods and apparatuses will become apparent from the following detailed description, claims, and drawings. The detailed description and specific examples are given by way of illustration only, since various changes and modifications within the spirit and scope of the description will become apparen t to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

10025] A further understanding of the nature and advantages of the present invention may be realized by reference to the following drawings. In the appended figures, similar

components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components ha ving the same first reference label irrespect ive of the second reference label. [9926j ' FIG. 1 is a diagram illustrating an example of a wireless communications system in accordance with various embodiments;

{ΘΘ27) FIG. 2 is a table illustrating TDD Uplink-Downlink configurations in exemplary wireless communications system in accordance with various embodiments;

{0028 j FIG. 3 illustrates a {"ell Clustering Interference Mitigation environment with cells grouped according to cell clusters in accordance with various embodiments;

{0029} FIG. 4 shows a diagram of an exemplary TDD frames with associated minimum and maximum numbers of uplink subframes in accordance with various embodiments;

10036} FIG. 5 shows a block diagram of an example of a base station in accordance with various embodiments;

|0031 FIG. 6 shows an exemplary pseudo-uplink grant, associated downlink subframe, and HARQ acknowledgment resource, in accordance with various embodiments;

{9032] FIG. 7 shows another example of pseudo-uplink grants, associated downlink subframes, and associated HARQ acknowledgment resources in accordance with various embodiments;

{0033] FIG. 8 shows an example of uplink gran ts, associated uplink subframes, pseudo- uplink grant and associated downlink subframe, and associated acknowledgment resources in accordance with various embodiments;

100341 FIG. 9 shows another example of uplink grants, associated uplink subframes, pseudo-uplink grants and associated downlink subframes, and associated ackiiowiedgment resources in accordance with various embodiments; f 0035 J FIG, 10 shows a block diagram of an example of a user equipment in accordance with various embodiments;

{0036] FIG- 1 1 shows a block diagram of an example of a TDD reconfiguration module in accordance with various embodiments;

{0037] FIG. 12 is a block diagram of an example of a wireless communications system including a base station and a mobile device in accordance with various embodiments; {0038} ' FIG. 13 is a flowchart of a method for dynamic reconfiguration of TDD UL-DL configuration in accordance with various embodiments;

{0039} FIG. 14 is a flowchart of another method for dynamic reconfigurat ion of TDD UL- DL configuration in accordance with various embodiments;

{0040} FIG. 15 is a flowchart of another method for dynamic reconfiguration of TDD UL- DL configuration in accordance with various embodiments; and

{0041} FIG. 1 is a flowchart of another method for dynamic reconfiguration of TDD UL- DL configuration in accordance with various embodiments.

DETAILED DESCRIPTION

{0042} Various aspects of the disclosure provide for reconfiguring a user equipment (UE) to operate in a reconfigured TDD UL-DL configuration. An initial uplink-downlink (UL- DL) configuration for TDD communication may be provided for communication between a base station and a UE. One or more subfirames within each frame transmitted using the initial UL-DL configuration may be identified as flexible subframes. The identification of flexible subframes may permit the identification of timing for HARQ transmissions that does not change when a reconfiguration takes place. A different UL-DL configuration may be transmitted to the UE, in which at least one flexible sisbframe is to be changed from an uplink subframe to a downlink subtrame. The different UL-DL configuration may be transmitted by, for example, a pseudo-uplink grant to the UE, which indicates that the UE is to reconfigure one or more subframes for uplink or downlink transmission.

{0043} Techniques described herein may be used for various wireless communications systems such as cellular wireless systems, Peer-to-Peer wireless communications, wireless local access networks (WLANs), ad hoc networks, satellite communications systems, and other systems. The terms "system" and "network" are often used interchangeably. These wireless communications systems may employ a variety of radio communication

technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA

(OFDMA), Single-Carrier FDMA (SC-FDMA), and/or other radio technologies. Generally, wireless communications are conducted according to a standardized implementation of one or more radio communication technologies called a Radio Access Technology (RAT), A wireless communications system or network that implements a Radio Access Technology may be called a Radio Access Network (RAN), £0044] Examples of Radio Access Technologies employing CDMA techniques include CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CD A2000 covers IS-2000, 1S-95, and IS-856 standards, IS-2000 Releases 0 and A are commonly referred to as

CDMA2000 I X, IX, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 I EV- DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and oilier variants of CDMA. Examples of TDM A systems include various implementations of Global System for Mobile Communications (GSM), Examples of Radio Access

Technologies employing OFDM and/or OFDMA include Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.1 1 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802,20, Flash-OFDM, etc, UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GS M are described in documents from an organization named "3rd Generation Partnership .Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generatio Partnership Project 2" (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies . jOlMSJ Thus, the following description provides examples, and is not limiting of the scope, applicability, or configuration set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the spirit and scope of the disclosure. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to certain embodiments may be combined in other embodiments. {0046} Referring first to FIG. I , a diagram illustrates an example of a w ireless

communications system 100. The system 100 includes base stations (or cells) 105, communication devices 1 15, and a core network 130, The base stations 105 may communicate with the communication devices 1 15 under the control of a base station

controller (not shown), which may be part of the core network 130 or the base stations 105 in various embodiments. Base stations 105 may communicate control information and/or user data with the core network 130 through backhaul links 132, Backhaul links may be wired backhaul links (e.g., copper, fiber, etc) and/or wireless backhaul Sinks (e.g., microwave, etc.). in embodiments, the base stations 105 may communicate, either directly or indirectly, with each other over backhaul links 1 4, which may be wired or wireless communication links. The system 100 may support operation on multiple carriers (waveform signals of different frequencies). Multi-carrier transmitters can transmit modulated signals simultaneously on the multiple carriers. For example, each communication link 125 may be a multi-carrier signal modulated according to the various radio technologies described above. Each modulated signal may be sent on a different, carrier and may cany control information (e.g., reference signals, control channels, etc), overhead information, data, etc. 00471 The base stations 105 may w relessly communicate with the devices 1 15 via one or more base station antennas. Each of the base station 1.05 sites may provide communication coverage for a respective geographic area 1. 1.0. In some embodiments, base stations .105 may be referred to as a base transceiver station, a radio base station, an access point, a radio transceiver, a basic service set (BSS). an extended service set (ESS), a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The coverage area 1 10 for base station may be divided into sectors making up only a portion of the coverage area (not shown). The system 100 may include base stations 105 of different types (e.g., macro, micro, and/or pieo base stations). There may be overlapping coverage areas for different technologies. {00481 The wireless network 100 may support synchronous or asynchronous operation.

For synchronous operation, the eNBs may have similar frame timing, and transmissions from different eNBs ma be approximately aligned in time. For asynchronous operation, the eNBs may have different frame timing, and transmissions from different eNBs may not be aligned in time. I embodiments, some eNBs 105 may be synchronous while other eNBs may be asynchronous. {004 j The communication devices 1 15 are dispersed throughout the wireless network UK), and each device ma be stationary or mobile. A communication device 1 15 may also he referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a user equipment, a mobile client, a client, or some other suitable terminology. A communication device 1 15 may be cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop ( WLL) station, or the like. A communication device may be able to communicate with macro base stations, pico base stations, femto base stations, relay base stations, and the like.

£0050] The transmission Sinks 125 shown in network 100 may include uplink (UL) transmissions from a mobile device 1 15 to a base station 105, and/or downlink (DL)

transmissions, from a base station 105 to a mobile device 1 15, The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions, in embodiments, the transmission links 125 are TDD carriers carrying bidirectional traffic within traffic frames.

|θί)51 | In embodiments, the system. 100 is an LTE/LTE-A network. In LTE LTE-A

networks, the terms evolved Node B (eNB) and user equipment (UE) may be generally used to describe the base stations 105 and communication devices 1 15, respectively. The system .100 may be a Heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical egions. For example, each eNB 1.05 may provide

communication coverage for a macro cell a pico cell, a femto ceil, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A pico cell would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto ceil would also generall cover a relativel small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an

association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a pico cell may be referred to as a pico eNB. And, an eNB for a femto cell may be referred to as a femto eNB or a home eNB. An eNB may support one or multiple (e.g., two. three, four, and the Like) cells. |0052 j The communications system 100 according to an LTE/LTE-A network architecture ma be referred to as an Evolved Packet System (EPS) 100. The EPS 100 may include one or more UEs 1 15, an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), an Evolved Packet Core (EPC) 1.30 (e.g., core network J 30), a Home Subscriber Server (HSS), and an Operator's IP Services. The EPS may interconnect with other access networks using other Radio Access Technologies. For example, EPS 100 may interconnect with a UTRAN- based network, and/or a CDMA-based network via one or more Serving GPRS Support Nodes (SGSNs), To support mobility of UEs 1 15 and/or load balancing, EPS 100 may support handover of UEs 1 15 between a source eNB 105 and a target eNB 105. EPS 1.00 may support intra-RAT handover between eNBs 105 and/or base stations of the same RAT (e.g., other E-UTRAN networks), and rater-RAT handovers between eNBs and/or base stations of different RATs (e.g., E-UTRAN to CDMA, etc.). The EPS 100 may provide packet-switched services, however, as those skilled in the art will readily appreciate, the various concepts presented throughout this disclosure may be extended to networks providing circuit-switched services. {0053] The E-UTRAN may include the eNBs 1 5 and may provide user plane and control plane protocol terminations toward the UEs 1 15. The eNBs 1 5 may be connected to other eNBs 1.05 via an X2 interface (e.g., backhaul link. 134). The eNBs 105 may provide an access point to the EPC 1.30 for the UEs 1 15. The eNBs 05 may be connected by an SI interface (e.g., backhaul link 132) to the EPC 130. Logical nodes within EPC 130 may include one or more Mobility Management Entities (MMEs), one or more Serving Gateways, and one or more Packet Data Network (PDN) Gateways (not shown). Generally, the MME may provide bearer and connection management All user I P packets may be transferred through the Serving Gateway, which itself may be connected to the PDN Gateway. The PD Gateway may provide U ' E IP address allocation as well as other functions. The PDN

Gateway may be connected to IP networks and/or the operator ' s IP Services. These logical nodes may be implemented in separate physical nodes or one or more may be combined in a single physical node. The IP Networks/Operator's IP Services .may include the Internet, an intranet; an IP Multimedia Subsystem (IMS), and or a Packet-Switched (PS) Streaming Service (PSS). 054] The UEs 1 .15 may be configured to collaboratively communicate with multiple eNBs 105 through, for example, Multiple Input Multiple Output (MIMO), Coordinated

Multi-Point (CoMP), or other schemes. MIMO techniques use multiple antennas on the base stations and/or multiple antennas on the UE to take advantage of multipath environments to transmit multiple data streams. CoMP includes techniques for dynamic coordination of transmission and reception by a number of eNBs to improve overall transmission quality for UEs as well as increasing network and spectrum utilization. Generally, CoMP techniques utilize backhaul links 132 and/or 134 for communication between base stations 105 to coordinate control plane and user plane communications fo the UEs 1 15.

10055) The communication networks that may accommodate some of the various disclosed embodiments may be packet-based networks that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer .may be IP-based.. A. Radio Link. Control ( RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport, channels. The MAC layer may also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC ' ) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between the UE and the network used for the user plane data. At the Physical layer, the transport channels may be mapped to Physical channels.

|0056] LTE/LTE-A utilizes orthogonal frequency division multiple-access (OFDMA) on the downlink and single-carrier frequenc division multiple-access (SC-FDMA.) on the uplink. OFDMA and SC-FDMA partition the system bandwidth into multiple ( ) orthogonal subcarriers, which are also commonly referred to as tones, bins, or the like. Each subearrier may be modulated with data. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, K may be equal to 72, 180, 00, 600, 00, or 1.200 with a subcarrier spacing of 1.5 kilohertz (KHz) for a corresponding system bandwidth (with guardband) of 1.4, 3, 5, 10, 15, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into sub-bands. For example, a sub-band may cover 1.08 MHz, and there may be 1, 2, 4, 8 or 16 sub-bands, 057] Wireless network 100 may support operation on multiple carriers, which may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), a channel., etc. The terms "carrier," "CC," and "channel" may be used interchangeably herein. A carrier used for the downlink may be referred to as a downlink CC, and a carrier used for the uplink may be referred to as an uplink; CC, A UE may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation. An eNB may transmit data and control information on one or more downlink CCs to the UE. The UE may transmit data and control information on one or more uplink CCs to the eNB. jOOSS) The carriers may transmit, bidirectional communications FDD (e.g., paired spectrum resources), TDD (e.g., unpaired spectrum resources). Frame structures for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2) may be defined. Each frame structure may have a radio frame length Tf — 307200 * T s = 10 ms and may include two half-frames of length 153600 · T s — 5 ms each . Each half- rame may include five subframes of length 30720 T s - 1 ms.

10059] For TDD frame structures, each sub frame may carry UL or DL traffic, and special subframes ("S") may be used to switch between DL to UL, transmission. Allocation of UL and DL subframes within radio frames may be symmetric or asymmetric and may be reconfigured semi -statically (e.g., C messages via backhaul, etc.). Special subframes may carry some DL and/or UL traffic and may include a Guard Period (GP) between DL and UL traffic. Switching from UL to DL traffic ma be achieved by setting timing advance at the UEs without the use of Special subframes or a guard period between UL and DL subframes. UL-DL configurations with switch-point periodicity equal to the frame period (e.g., 10 ms) or half of the frame period (e.g., 5 ms) may be supported. For example, TDD frames may include one or more Special frames, and the period between Special frames may determine the TDD DL-to-UL switch-point periodicity for the frame. For LTE/LTE-A, seven different UL-DL configurations are defined that provide between 40% and 90% DL subframes as illustrated in table FIG. 2 at Table 200. As indicated in table 200, there are two switching periodicities, 5 ms and 10 ras. For configurations with 5 ms switching periodicities,, there are two special subframes per frame, and for configurations with 10 ms switching periodicities there is one special subframe per frame. Some of these configurations are symmetric, having the same number of uplink and downlink subframes, while some are asymmetric, having different numbers of uplink and downlink subframes. For example, UL-DL configuration 1 is symmetric, with four uplink and four downlink subframes, UL-DL configuration 5 favors downlink throughput, and UL-DL configuration 0 favors uplink throughput.

10060] The particular TDD UL/DL configuration that is used by a base station may be based on user requirements for the particular coverage area. For example, with reference again to FIG. 1 if a relatively large number of users in a coverage area .1 10 are receiving more data than they are transmitting, the UL-DL configuration for the associated base station 105 may be selected to favor downlink throughput. Similarly, if a relatively large number of users in a coverage are 110 are transmitting more data than they are receiving, the UL-DL configuration for the associated base station 105 may be selected to favor uplink throughput and the base station 105 may operate using UL-DL configuration 0. In some aspects, a base station 105 may be able to dynamically reconfigure TDD UL-DL configurations on a frame- by-frame basis. In such cases, UEs 1 .15 that are reconfigured may receive the reconfiguration message, and transmit receive subframes on subsequent TDD frames using the reconfigured UL-DL configuration. Such capabilities allow for relatively fast switching for the

reconfigured UEs 1 15 according to the instantaneous traffic situation, and may provide enhanced packet throughput between the UEs 115 and base station 105. A UE 1 15, for example, may be in communication with a base station 105 using an initial TD D UL-DL configuration. This initial TDD UL-DL configuration, however, may become unfavorable for efficient packet throughput at a later point in time. For example, the user may switch from receiving a relatively large amount of data to transmitting a relatively large amount of data. In such a situation, a ratio of uplink to downlink transmission data may have a

significant change, which may result a previously favorable UL-DL configuration becoming an unfavorable UL-DL configuration.

{0061 } FIG. 3 illustrates a Cell Clustering and interference Mitigation (COM)

environment 300 with eNBs grouped according to cell clusters. COM environment 200 may illustrate, for example, aspects of wireless communication system 100 illustrated in FIG. 1. Cell clusters can include one or more eNBs and eNBs within a cell cluster may be different types (e.g., macro eNB, pico eNB, femto eNB, and/or the like). As illustrated in the example of FIG. 3, CCIM environment 300 includes ceil clusters 320-a, 320-b, and 320-c. Cell cluster 320-a may include eNB 305-a and eNB 105~b, cell cluster 320-b may include eNB 105-c, and eel! cluster 320-c may include eNBs 105-d and 105-e. Cell clusters 320 may be staticall or serai-statieaiiy defined and each eNB 105 in a cluster 320 may be aware of the other eNBs 105 of i ts cluster. Cell clusters 320-a, 320-b. and/or 320-c may deploy TDD carriers and TDD UL-DL configuration within each cell cluster may be synchronized.

{0062] Traffic adaptation for synchronized TDD UL-DL configuration within a cell cluster ma be performed by coordination of TDD UL-DL reconfiguration between cells of the cluster. Semi-static (e.g., on the order of tens of frames) TDD UL-DL reconfiguration may be performed by exchange of control-plane messaging among eNBs (e.g., via S i and/or X2 interfaces, etc.). While semi-static TDD UL-DL reconfiguration may provide adequate performance under some conditions, when traffic conditions within the cluster change rapidly, semi-static TDD UL-DL reconfiguration may result in sub-optimal allocation of UL- to-DL subframes for TDD carriers used in the cluster. In some aspects, rapidly changing traffic conditions may be accommodated through allowing the UL-DL configuration for a particular IJE 1 15 may be reconfigured dynamically. Such dynamic reconfiguration may be transmitted to a UE 1 15 through signaling from the eNB 105, such as through control channel signaling, and apply to one or more subsequent TDD frames. Such reconfigurations may be accomplished according to "enhanced Interference Management and Traffic Adaptation" (elMTA), which may be implemented in some etworks.

{0063] in such networks, e!MTA compatible UEs may receive dynamic reconfiguration messages indicating that particular subframes within a TDD frame may be switched from an uplink to a downlink subframe. in some networks, the adaptation rate may be relatively fast, such as 10 ms, thus providing ability in some situations to change TDD UL-DL

configurations on a frame-by-frame basis. UEs that are capable of operating according to elMTA are referred to herein as non-legacy UEs, and UEs that are not capable of operating according to elMTA. are referred to herein as legacy UEs. In some situations, an eNB may be in communication with both legacy UEs and non- legacy UEs, and thus signaling between (he UEs and eNB mus be provided to allow the legacy UEs to operate properly while also allowing dynamic reconfiguration for non-legacy UEs as well as other related signaling, such as HARQ acknowledgements, to be carried out between the UEs and an eNB. To support legacy UEs, a downlink subtrame in an established TDD UL-DL configuration, such as indicated in System information Block 1 (SiB l), cannot be changed to an uplink subtrame, as such a change may result in a Radio Resource Management (RRM) measurement and/or periodic Channel State information (CSi) reporting problem. An eNB operating according to eJMTA may, however, modify scheduling information for legacy UEs and configure resources to certain uplink subframes in order to "blank" UL subframes that are reconfigured to be downlink subframes in non-legacy UEs, In some aspects, a signaling mechanism is provided to signal dynamic reconfiguration to one or more U Es.

10064} The timing for the transmission of HARQ infonnation in a TDD system is determined according to the particular TDD UL-DL. configuration. Various aspects pro vide that 11 ARQ times may be determined based on properties of various subframes within a TDD frame. For example, FIG. 4 illustrates a frame 400 in a TDD system. The frame 400 includes 10 subframes 405, that are designated as an uplink subf ame "U" a downlink subframe ** D", a special subframe "S" or a flexible subframe "U/D." In the example of FIG. 4, subframes 4, 7, and 8 are indicated as being flexible subframes. In this example, a

minimum numbe of uplink subframes 410 includes the subframes that are indicated as uplink subframes and cannot be reconfigured to be downlink subframes. A maximum number of subframes 415 includes the subframes that are indicated as uplink subframes according to the initial UL-DL configuration. Thus, in any given frame that is transmitted according to the TDD UL-DL configuration of this example may have uplink data in

subframes 2 and 3, and optionally in one or more of subframes 4, 7, or 8.

10065] In some examples, subframes 4, 7, and 8 are initially set to be uplink subframes through, for example, a system information block (SIB) message. Legacy UEs that receive this message will simply operate according to the defined TDD UL-DL configuration. Non- legacy UEs, may, in some examples, receive signaling that indicates the minimum number of uplink subframes 410 and the maximum number of uplink subframes 415. In some examples, the minimum uplink subframe* 41 identification and maximum uplink subframes 415 identification may be transmitted in bitmaps that are transmitted to the UE. In other examples, a set of semi-static TDD UL-DL. minimum and/or maximum uplink subframe identifications may be established, and a configuration index may be received at the UE through, for example, RRC signaling that identifies the minimum uplink subframes 410 and/or maximum uplink subframes 415. For example, eight semi-static identifications of minimum uplink subframes may be established, which may be identified by a three-bit configuration index, with the three-bit configuration index received at the UE to identify the minimum uplink subfxames. The UE may then identify the minimum and maximum uplink subframes, and also the flexible siibframes. In some embodiments, the maximum number of subframes 415 may be determined based on the TDD UL-DL configuration provided in the SIB message, and the minimum siibframes 410 may be determined based on a bitmap or configuration index transmitted to the UE in an RRC message. In other embodiments, the UE may receive an indication of a second TDD UL-DL configuration, which may be used to identify the minimum subframes 1.0. In any case, IIL subframes in set 4.15 but not in set 410, identified as flexible subframes, may be dynamically changed to downlink subframes for fast traffic adaptation, in some examples, the definition of the maximum and minimum uplink subframes can be based on hysteresis of uplink traffic toad during an upcoming time,

(0066) As mentioned above, non-legacy UEs may be dynamically reconfigured to operate according to different TDD UL-DL configurations. When reconfiguring a UE, both MARQ timelines and reconfiguration signaling transmitted to the UE are provided in various

examples. In some embodiments, uplink HA .Q processes and acknowledgment/negative acknowledgment (ACK/NACK) position are determined based on the configuration with maximum uplink subframe set. Thus, regardless of reconfiguration of one or more of the flexible subframes, the UE will be able to provide uplink HARQ information, in a consistent manner. Examples of uplink HARQ processes and ACK/NACK position will be described in more detail below, in some embodiments, downlink HARQ process and ACK/NACK positions are determined based on the TDD UL-DL configuration with the minimum uplink subframe set (i.e., the configuration having the maximum number of downlink subframes). Thus, regardless of reconfiguration of one or more of the flexible subframes, the UE will be able to provide downlink HARQ information in a consistent manner, hi such a manner, such embodiments provide consistent. HARQ timing for non-legacy UEs across different dynamic- reconfigurations. {0067j As also mentioned above, TDD UL-DL reconfiguration information is provided to non-legacy UEs to dynamically change uplink/downlink bandwidth between the base station and the UE. In some examples, signaling is provided to the UE through L I signaling from the base station to the UE. In some examples, the UE receives an uplink grant for uplink sub frame, with a pseudo-uplink grant provided for any flexible sub frames tha , are to be downlink subframes during a given frame. Such a pseudo-uplink grant, thus informs the UE of a change in the transmission direction for the particular subirame. Only a UE that receives the pseudo-uplink grant will 117 to detect the downlink grant in the corresponding flexible subirame, thus saving power as compared to a UE having to receive and attempt to decode flexible subframes. Thus, a base station may signal to enable or disable downlink

transmission in flexible subframes on a per-UE basis.

{0068] In some embodiments, a pseudo-uplink grant may be denoted by an invalid resource block allocation in Downlink Control Information (DC!) format. 0. According to the specifications for some communications systems, the number of bits for a resource indication value (Rl ' V) exceeds the possibilities ofRIVs. For example, in some versions of the E- UTRAN specifications, 13 bits are provided for the RIV, with a maximum number ofRIVs being defined to be 5049. These specifications describe that a UE is to discard an uplink resource allocation in such a format if consistent control information is ot detected. Thus, providing such a pseudo-uplink grant conforms with such specifications, and el TA capable UEs may use such an allocation as an indication to change the transmission direction on a flexible subirame associated with the resource. For example, with continued reference to FIG. 4, a RIV in a uplink grant associated with subirame 4 may be set to exceed the maximum RIV value. The non-legacy UE that, receives this RIV may then recognize that the subirame 4 is to be used for reception of a downlink transmission. Examples of pseudo- uplink grants and reconfiguration of associated subframes will be described in more detail below. f0069| In order to provide reconfiguration signaling and consistent HARQ resource allocation in ei TA systems, various aspects of the present disclosure provide for transmission of information related to the maximum and minimum number of uplink subframes that may be configured for TDD frames, as well as indications of particular subframes that are to be changed from uplink to downlink, or downlink to uplink. This allows -non-legacy UEs that are compatible with e!MTA to transmit information without collision with legacy UEs operating with the same eNB, FIG. 5 shows a block diagram of a communications system 500 thai may be configured for reconfiguration of TDD UL-DL configuration. This system 500 may be an example of aspects of the system 100 depicted in FIG. I , or system 300 of FIG, 3. System 500 may include a ba.se station 105-a. The base station 105- f may include a.menna(s) 545, a transceiver module 550, memory 570, and a processor module 560, which each may be in communication, directly or indirectly, with each other (e.g., over one or more buses 580). The transceiver module 550 may be configured to communicate bi-directionally, via the antemia(s) 545, with UE devices 1 15 -a, 11 -b. The transceiver module 550 (and/or oilier components of the base station 105-f) may also be configured to communicate bi-directionally with one or more networks, In some cases, the base station 105-f may communicate with the core network 130-a through network communications module 565. Base station 105-f may be an example of an eNodeB base station, a Home eNodeB base station, a NodeB base station, and/or a Home NodeB base station,

(0070} Base station 105-f may also communicate with other base stations 105, such as base station 105~m and base station 105-n. i n some cases, base station 105-f may communicate with other base stations such as 105-m and/or 105-n utilizing base station communication module 515. in some embodiments, base station communication module 15 may provide an X2 interface within an LTE wireless communication technology to provide communication between some of the base stations 105. In some embodiments, base station 105-f may communicate with other base stations through core network 130-a.

1 0711 The memory 570 ma include random access memory (RAM) and read-only memory (ROM). The memory 570 ma also store computer-readable, computer-executable software code 575 containing instructions that are configured to, when executed, cause the processor module 560 to perform various functions described herein (e.g., TDD UL-DL reconfiguration, HA Q operations, etc.). Alternatively, the software code 575 may not be directly executable by the processor module 560 but be configured to cause the processor, e.g., when compiled and executed, to perform functions described herein.

{1)072) The processor module 560 may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an application-specific , integrated circuit (ASIC), etc. The transceiver niodule(s) 550 may include a modem configured to modulate the packets and provide the modulated packets to the antenna(s) 545 for transmission, and to demodulate packets received from, the anteiina(s) 545. While some examples of the base station 105-f may include a single antenna 545, the base station 105-f may include multiple antennas 545 for multiple links which may support carrier aggregation. For example, one or more links may be used to support macro communications with UE devices 1 1 5-a, 1 15-b.

| 73| According to the architecture of FIG. 5, the base station 105-f may further include a commiHiications management module 540. The communications management module 540 may manage communications with other base stations 105. By way of example, the

communications management module 540 may be a component of the base station 105-f in communication with some or all of the other components of the base sta tion 105-f via a bus 580, Alternatively, functionality of the communications management module 540 may be implemented as a component of the transceiver module 550, as a computer program product, and/or as one or more controller elements of the processor module 560.

|00?4| In some embodiments, the transceiver module 550 in conjunction with antenna(s) 545, along with other possible components of base station 105-f, ma determine TDD UL- DL configurations for various UEs communicating with the base station 105-f, and also determine uplink resources for non-legacy UEs that may be reconfigured with different TDD UL-DL configurations. In some embodiments, base station 105-f includes a TDD UL-DL configuration selection module 520 that determines a TDD UL-DL configuration for UEs 15-a, 1 15-b, As discussed above, in some aspects different UEs 1 15-a, 1 15-b, may include legacy UEs and non-legacy UEs, and TDD UL-DL configuration module 520 may determine UL-DL configurations for both legacy and non-legacy UEs. In the embodiment of FIG, 5, UE 1 15-a may be a legacy UE, and UE 1 15-b may be a non-legacy UE. The TDD UL-DL configuration for legacy UE 1 15-a may be transmitted via SIB1 using TDD UL-DL

configuration transmission module 525, in conjunction with transceiver raodule(s) 550, Likewise, an initial TDD UL-DL configuration for non-legacy UE 1 15-b may be transmitted using S1B1 , using TDD UL-DL configuration transmission module 525 in conjunction with transceiver module(s) 550. TDD UL-DL configuration selection module 520 may also periodically determine that the default TDD UL-DL configuration for legacy UE 1 15-a is to be changed, in which case updated SIB! blocks may be transmitted using TDD UL-DL configuration transmission module 525, in conjunction with transceiver module(s) 550. The TDD UL-DL configuration module also, in some embodiments, may generate one or more messages that indicate the minimum number of uplink subframes and the maximum number of uplink subframes that may be configured for non-legacy UE 3 15-b. Such messages may be transmitted to the UEs 1 15 using the TDD UL-DL configuration transmission module 525. In some examples, an identification of the minimum uplink subframes may be provided through a bitmap transmitted to the UE in an RRC message, and the identification of the maximum set of uplink of subframes may be determined based on the T D UL-DL

configuration provided in the SIB message. In some examples, an identification of the minimum uplink subframes may be determined based on a second semi-static TDD UL-DL configuration transmitted to the UE in an RRC message. In some examples, the definition of the maximum and minimum uplink subframes can be based on hysteresis of uplink traffic load during an upcoming time.

{00751 At some point, traffic patterns may change such than an initial TDD UL-DL configuration is not optimal for one or more UEs 115-a and 1 15-b. In the case of non-legacy UE 1 15-b, UL-DL reconfiguration determination module 530 may determine that the UL-DL configuration for non-legacy UE 1 15-b is to be reconfigured to a different UL-DL

configuration. For example, changes in traffic between the base station 105-f and non-legacy UE 1 15-b may change such that additional, data is to be transmitted to non-legacy UE 1.15-b, in which case UL-DL reconfiguration determination module 530 may determine that non- legacy UE 1 15-b is to be reconfigured to operate according to a. different UL-DL

configuration. Reconfiguration information may be provided to UL-DL reconfiguration transmission module 535, which may transmit TDD UL-DL reconfiguration messages, m conjunction with transceiver niodule(s) 550, to the UE 1 15-b. In some embodiments, the UL- DL reconfiguration determination module 530 ma generate a pseudo-uplink grant that is to be transmitted to the UE 1 15-b to notify the UE 115-b that a particular subframe is to be changed from an uplink subframe to a downlink subframe. UL-DL reconfiguration transmission module 535 may transmit such a pseudo-uplink grant, in conjunction with transceiver module(s) 550, to the UE 1 15-b. As mentioned above, such a pseudo-uplink grant may be an invalid R.IV that is transmitted to the UE, which indicates to the UE that a particular subframe is to be changed from an uplink subframe to a downlink subframe. (0076j As mentioned above, a pseudo-uplink grant may be used in some embodiments to signal to a UE that a particular subframe is to be changed from an uplink subfrarae to an downl ink ' subframe. FIG, 6 illustrates an example 600 of such a pseudo-uplink message transmission to reconfigure a non-legacy UE to operate according to a different TDD UL-DL configuration than an initially configured TDD UL-DL configuration. In this embodiment, three frames are illustrated, namely frame n 605, frame n+ 1 610, and frame n ; 2 615, Initially, transmissions are conducted according to TDD UL-DL configuration 6. In this example, subfram.es 2 and 3 are identified as the minimum subframes in a subframe set 620. This identification may be accomplished, as mentioned above, through RRC signaling from a base station to a UE. Because the initial TDD UL-DL configuration is configuration 6, the UE can identify flexible subframes 625 as the difference between the minimum identified uplink sublxames and the uplink subframes associated with TDD UL-DL configuration 6, In some embodiments, it may be established that HARQ information in such a situation is to be transmitted from a UE to a base station during subframes 2 and 3, namely the subframes identified in the minimum set of subframes 620. Following the first frame 605, HARQ

ACK/NACK information for the downlink information m subframes identified as #1 , #2, and #3 is transmitted in subframe 2 of the second frame 610. HARQ ACK/NACK information for the downlink information in subframes identified as #4 and #5 is transmitted in the third subframe of the second frame 610, according to this example. Furthermore, downlink information in subframe identified as #5 may include a pseudo-uplink grant 635 associated with the first .flexible subframe 630 in the second frame 610. The UE will the know that subframe 630 is to be reconfigured as a downlink subframe. The HARQ ACK/NACK information for this downlink; subframe 630 is then transmitted In subf ame 2 of the third frame 15. Following the pseudo-uplink grant 635, no further pseudo-uplink grants are transmitted in this example, and thus the TDD UL-DL configuration for the third frame 615 returns to the initial TDD UL-DL configuration. In such a manner, the UE may be signaled to reconfigure uplink and downlink subframes, and also provide HARQ information in a consistent manner.

(0077} FIG. 7 illustrates another example 700 of such a pseudo-uplink message transmission to reconfigure a non-legacy UE to operate according to a different TDD UL-DL configuration than an initially configured TDD UL-DL configuration. In this embodiment, three frames are illustrated, namely frame n 705, frame n+1 710, and frame +2 715. Initially, transmissions are conducted according to TDD UL-DL configuration 6. in this example, as in the example of FIG. 6, subframes 2 and 3 are identi fied as the minimum subframes in a subframe set 720. This identification may be accomplished, as mentioned above, through RRC signaling from a base station to a UE. Because the initial TDD UL-DL configuration is configuration 6, the UE can identify flexible subframes 725 as the difference between the minimum identified uplink subframes and the uplink subframes associated with TDD UL-DL configuration 6. in some embodiments, it may be established that HARQ information in such a situation is to be transmitted from a UE to a base station during subframes 2 and 3, namely the subframes identified in the minimum set of subframes 720, Following the first frame 705, HARQ ACK/NACK information for the downlink information in subframes identified as #L #2 , and #3 is transmitted in subframe 2 of the second frame 710. HARQ ACK/NACK. information for the downlink information in subframes identified as #4 and #5 is transmitted in the third subframe of the second frame 710, according to this example. In this example, downlink information in subframe #5. #6, and #7 may include pseudo-uplink grants 735, 740, and 745 associated with each of the flexible subframes 730, 750, and 755 in the second frame 710. The UE will then know that subframes 730, 750, and 755 are to be reconfigured as downlink subframes. The HARQ ACK/NACK information for these downlink subframe 730, 750, and 755 is then transmitted in subframes 2 and 3 of the third frame 715. Following the pseudo-uplink grants 735, 740, and 745 no further pseudo- uplink grants are transmitted in this example, and thus the TDD UL-DL configuration for the third frame 715 returns to the initial TDD UL-DL configuration, in such a manner, the U E may be signaled to reconfigure uplink and downlink subframes, and also provide HARQ information in a consistent manner.

10078] With reference now to FIG. 8, an example 800 of uplink HARQ timing for TDD reconfiguration is described. In this embodiment, three frames are illustrated, namely frame n 80S, frame ti+1 81 , and frame W--2 815. initially, transmissions are conducted according to TDD UL-DL configuration 6. In this example, subframes 2 and 3 are identified as the minimum subframes in a subframe set 820. This identification may be accomplished, as mentioned above, through RRC signaling from a base station to a UE. Because the initial TDD UL-DL configuration is configuration 6, the UE can identify flexible subframes 825 as the difference between the minimum identified uplink subframes and the uplink subframes associated with TDD UL-DL configuration 6. In some embodiments, it may be established that uplink HARQ information, namel HARQ infonnatio used to confirm that transmissions from the UE are properly received, is transmitted in downlink information provided in either downlink subframes or special subframes. In the example of FIG. 8, the G indicates an uplink grant indication provided to the (IE, with grant information 835 in this example containing an invalid uplink grant. This indicates to the UE that the subframe 830 associated with the invalid uplink grant is to be reconfigured to be a downlink subi ame, rather than an uplink subirame. Uplink HARQ information, receipt of which is indicated with "P" in this example, is not received back at the UE for this subframe, due to the changed status of the subframe. Following the pseudo-uplink grant 835, no farther pseudo-uplink grants are transmitted in this example, and thus the TDD UL-DL configuration for the third frame 815 returns to the initial TDD UL-DL configuration. In such a manner, the UE may be signaled to reconfigure uplink and downlink subframes, and also provide/receive HARQ information in a consistent manner.

10079] With reference now to FIG. 9, another example 900 of uplink HARQ timing for TDD reconfiguration is described. In this embodiment, three frames are illustrated, namely frame n 905, frame n÷ 1 10, and frame n- -2 915. Initially, transmissions are conducted according to TDD UL-DL configuration 6. In this example, subframes 2 and 3 are identified as the minimum subframes in a subframe set 920. This identification may be accomplished, as mentioned above, through R C signaling from a base station to a UE. Because the initial TDD UL-DL configuration is configuration 6, the UE can identify flexible subframes 925 as the difference between the minimum identified uplink subframes and the uplink subframes associated with TDD UL-DL configuration 6. in some embodiments, it may be established that uplink HARQ information, namely HARQ information used, to confirm that

transmissions from the UE are properly received, is transmitted in downlink information provided in either downlink subframes or special subframes. In the example of FIG. 9, the G indicates an uplink grant indication provided to the UE, with grant information 935, 940, and 945 in this example containing an invalid uplink grants. This indicates to the UE that subframes 930, 950, and 955 associated with the invalid uplink grant are to be reconfigured to be downlink subframes, rather than uplink subframes. Uplink HARQ information, receipt of which is indicated with "P" in this example, is not recei ved back at the UE for the reconfigured subframes, due to the changed status of the subframe. Following the pseudo- uplink grants 935, 940, and 945 no further pseudo-uplink grants are transmitted in this example, and thus the TDD UL-DL configuration for the third frame 915 returns to the initial TDD UL-DL configuration. In such a maimer, the UE may be signaled to reconfigure upl nk and downlink subframes, and also provide/receive HARQ information m a consistent manner.

|0080| According to some examples, a base station may determine the TDD UL-DL configuration and reconfiguration associated with a UE, and also transmit information related to the minimum number of uplink subframes as well as reconfiguration messages that the UE is to use for communication with the base station. The UE will receive this information, switch to the new TDD UL-DL configuration as indicated by reconfiguration messages, and transmit Il ARQ information using identified uplink resources based on the minimum number of uplink subframes. With reference now to FIG, 10, an example wireless communication system 1000 that performs TDD UL/DL reconfigurations is depicted. System 1000 includes a UE 1 1.5-c that may communicate with base station 105-g to receive access to one or more wireless networks, and may be an example of aspects of the system 100 of FIG. 1, system 300 of FIG. 3, or system 500 of FIG, 5, UE 1 15-c may be an example of a user equipment 115 of FIGS. 1, 3, or 5. UE 1 15-c, includes one or more antenna(s) 1005 communicatively coupled to receiver module(s) 1010 and transmitter moduie(s) 1015, which are in turn communicatively coupled to a control module 1020. Control module 1020 includes one or more processor moduie(s) 1025. a memory 1030 thai may include software 1035, and a TDD reconfiguration module 1040. The software 1035 may be for execution by processor module 1025 and/or TDD reconfiguration module 1040. 0081 J The processor module(s) 1025 may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc. The memory 1030 may include random access memory (RAM) and read-only memory (ROM). The memory 1030 may store computer-readable, computer-executable software code 1035 containing instructions that are configured to, when executed (or when compiled and executed), cause the processor module 1025 and/or TDD reconfiguration module 1040 to perform various functions described herein (e.g., TDD UL-DL

reconfiguration, and transmission of HARQ information on identified uplink resources). The TDD reconfiguration module 1040 may be implemented as a part of the processor module(s) 1 25, or may be implemented using one or more separate CPUs or ASICs, for example. The transmitter module(s) J015 may transmit to base station I05-g (and/or other base stations) to establish communications with one or more wireless communications networks (e.g., E- UT AN, UT AN, etc.), as described above. The TDD reconfiguration module 1040 may be configured to receive TDD reconfiguration messages from base station 105-g and change a TDD UL-DL configuration based on the received messages, such as based on the receipt of pseudo-uplink grams for particular subfranies. The TDD reconfiguration module 1040 may also be configured to receive reconfigur tion messages for the identification of reconfigured subframes, such as provided in examples as described above. The receiver modii!e(s) 1010 may receive downlink transmissions from base station 1 5-g (and/or other base stations), such as described above. Downlink transmissions are received and processed at the user equipment 1 15-e. The components of UE 115-c may, individually or collectively, be implemented with one or more Application Specific Integrated Circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the UE 1 15-c.

|0082} FIG. I t illustrates an example of a TDD reconfiguration module 1040-a, which includes a TDD UL-DL configuration determination module 1105, a UL-DL reconfiguration determination module, 1 1 1 , a 1:1 ARQ ACK/NACK determination module 1 1 15, and a

HARQ ACK/NACK transmission module 1 120. The TDD UL-DL configuration

determinalion module 1 1 5 may recei e TDD UL-DL configuration information from a base station, and set the TDD UL-DL configuration according to the information. This

information may be received through a system information block (e.g., SI B 1 ), or may be received through one or more reconfiguration messages received from the base station in accordance with elMTA, for example. The TDD UL-DL configuration information may also include information related to a minimum set of sub.frames that are uplink subframes, which may be used to determine timing for providing HARQ ACK/NACK information. The UL- DL reconfiguration determination module 11 10 may receive reconfiguration messages, such as uplink resource grants and pseudo-uplink resource grants, and determine that one or more subfranies are to be reconfigured from uplink to downlink subframes, such as described above. HARQ ACK/N ACK determination module 1 1 15 may determine the appropriate ACK NACK message to transmit based on the successful or unsuccessful receipt of downlink data in the associated downlink subfranies. The HARQ ACK/NACK transmission module 1 120 ma receive the ACK/NACK information and the uplink resource information, and transmit the HARQ information on the identified uplink resource. The components of TDD reconfiguration module 1 140-a .may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the TDD reconfiguration module 1 140-a,

{0083} FIG. 12 is a block diagram of a system 1200 including a base station ! 05~h and a mobile device 1 15-d. This system 1200 may be an example of the system 100 of FIGS. 1, system 300 of FIG. 3, system 500 of FIG. 5, or system 1000 of FIG. 10. The base station 105-h may be equipped with antennas 1234-a through 1234-x, and the mobile device 1 15-d ma be equipped with antennas 1252-a through 1252-n. At the base station .1 S-h, a transmit processor 1220 may receive data from a data source.

11 ) 084] The transmit processor 1220 may process the data. The transmit processor 1220 may also generate reference symbols, and a cell-specific reference signal A transmit (TX) M1MO processor 1230 may perform spatial processing (e.g., precoding) on data symbols, control symbols, and/or reference symbols, if applicable, and may provide output symbol streams to the transmit modulators 1232-a through 1.232 -x. Each modulator 1232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 1232 may further process (e.g., convert t analog, amplify, filter, and upconvert) the output sample stream to obtai a downlink (DL) signal In one example, DL signals from modulators i232-a through 1232-x may be transmitted via the antennas 1234-a through 1234-x, respecti vely according to a particular TDD Uplink/Downlink configuration.

(0085J At the mobile device 1 15-d, the mobile device antennas 1252-a through 1.252-n may receive the DL signals according to the particular TDD Uplink/Downlink configuration from the base station 105-h and may provide the received signals to the demodulators 1254-a through 1254-n, respectively. Bach demodulator 1.254 may condition (e.g., filter, amplify downconvert, and digitize) a respecti e received signal to obtain input samples. Each demodulator .1254 may further process the input samples {e.g.. for OFD , etc, ) to obtain received symbols. A MIMO detector 1256 may obtain received symbols from all the demodulators 1254-a through 1254-n, pertonn MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 1258 may process (e.g.. demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the mobile device 1 15-d to a data output, and provide decoded control information to a processor J 280, or memory 1282, The processor 1280 may be coupled with a TDD reconfiguration module 1284 that may reconfigure the TDD UL-DL configuration of mobile device 1 15-d, such as described above. The processor 1280 may perform frame formatting according to a current TDD UL/DL configuration, and may thus flexibly configure the TDD UL/DL frame structure based on the current UL/DL configuration of the base station 105-h.

|βί)86] On the uplink (UL), at the mobile device J 15-d. a transmit processor 1264 may receive and process data from a data source. The transmit processor 1264 may also generate reference symbols for a reference signal. The symbols from the transmit processor 1264 ma be precoded by a transmit ΜΪΜΟ processor 1266 if applicable, further processed by the demodulators 1254-a through 1254-n (e.g., for SC-FDMA. etc.), and be transmitted to the base station 105-h in accordance with the transmission parameters received from the base station 105-h. At the base station 105-h, the UL signals from the mobile device 1 15-d may be received by the antennas .1234, processed by the demodulators 1232, detected by a MIMO detector 1236 if applicable, and further processed by a receive processor 1238. The receive processor 1238 may provide decoded data to a data output and to the processor 1240, A memory 1.242 may be coupled with the processor 1240, The processor 3240 may perform frame formatting according to a current TDD UL/DL configuration. A. TD UL/DL configuration module 1244 may, in some embodiments, configure or reconfigure the base station 105-h, or one or more carriers of the base station 105-h, to operate according to different TDD UL/DL configurations, and transmit information related to the reconfigured UL-DL configurations to mobile device 1 15-d, such as described above. Similarly as discussed above, system 1200 may support operation on multiple component carriers, each of which include waveform signals of different frequencies that are transmitted between base station 105-h and devices 1 15-d. Multiple component carriers may carry uplink and downlink transmissions between mobile device 1 15-d and base station 105-h, and base station 105-h may support operation on multi le component carriers that may each have different TDD configurations. In some embodiments, the TDD UL/DL configuration module 1244 may dynamically reconfigure the TDD UL/DL configuration of base station 105-h carriers according to real-time or near real-time communications through the base station 105-h. The components of the mobile device 1 15-d may, individually or collectively, be implemented with one or more Application Specific Integrated Circuits (ASICs) adapted to perform some or all of the appli cable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the system 1.200. Similarly, the components of the base station I05-h may, individually or collectively, be implemented with one or more Application Specific Integrated Circuits (ASICs) adapted to perform some or all of the applicable functions in ' hardware. Each of the noted components may be a means for performing one or more functions related, to operation of the system 1200.

|0O87j FIG. L illustrates a method 1300 that may be carried out by a base station a wireless communications system according to various embodiments. The method 1300 may, for example, be performed by a base station of FIG. 1. 3, 5, 1.0, or 1.2. or using any combination of the devices described for these figures. Initially, at block 1305. the base station determines an initial uplink-downlink (UL-DL) configuration for TDD

communication with the UE. For example, the UE may be a non-legacy UE thai may operate according to elMTA to be reconfigured to change TDD UL-DL configurations. The initial UL-DL configuration may be provided, for example, through system information blocks, for example. At block .131.0, the base station identifies one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes. Such an

identification may be transmitted using, for example, a bitmap or a second semi-static TDD UL-DL configuration that indicates the minimum uplink subframes that cannot be reconfigured from uplink to downlink subframes, with the flexible subframes determined based on the minimum uplink subframes and the uplink subframes associated with the initial UL-DL configuration. At block 1315, the base station determines a different. UL-DL configuration is to be used for TDD communication with the UE, the different UL-DL configuration comprising at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe. At block 1320, the base station transmits a reconfiguration message to the UE, indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe in the second frame. The reconfiguration message may be, for example, transmitted through physical layer (PHY) signaling to the UE, or may include a pseudo-uplink grant for the at least one flexible subframe that is to be changed from an uplink subframe to a downlink subframe in the second frame. In some examples, such as described above, HARQ acknowledgment timing is unchanged between the initial UL-DL configuration and the HARQ timing for the reconfigured UL-DL configuration and may be based on the configuration of the maximum number of uplink sub frames for uplink HARQ information and based on the minimum number of uplink subframes for downlink HARQ information. {0088) FIG. 14 illustrates another method 1400 that may be carried out by a base station a wireless communications system according to various embodiments. The method 1400 may, fo example, be performed b a base station of FIG. 1, 3, 5, 10, or 12, or using any combination of. the devices described for these figures, initially * at block 1405, the base station transmits an initial uplink-downlink (UL-DL) configuration for TDD communication to the UE. At block 1.410, the base station transmits a pseudo-uplink grant to the UE to reconfigure the UL-DL configuration to a different UL-DL configuration, in some examples, the pseudo-uplink grant comprises an invalid resource block allocation for at least one subframe of a TDD frame. Such an invalid resource block allocatio may include a resource indication value (RIV) that exceeds a maximum value of an RiV for an uplink grant in some examples, similarly as described above, the pseudo-uplink grant may include a first pseudo- uplink grant for a first of the flexible subframes of a TDD frame, and the base station may transmit a second pseudo-uplink grant for a second of the flexible subframes of the TDD frame. In such a manner, subframes in a TDD communication may be reconfigured dynamically, allowing for increased flexibility in uplink and downlink bandwidth with, the particular HE,

{0089} FIG. 15 illustrates a method 1500 that may be carried out by a user equipment in a wireless commnnications system according to various embodiments. The method. 1500 may, for example, be performed by a user equipment of FIG. I, 3, 5, 10, or 12, or using any combination of the devices described for these figures. Initially, at block 1505, the user equipment receives an initial uplink-downlink. (UL-DL) configuration for TDD

communication with the base station. Such an initial UL-DL configuration may include, such as described abo ve, a maximum number of uplink subframes within each frame and/or a minimum number of uplink subframes within each frame. In some examples, the UE may determine uplink HARQ acknowledgment position within the subframes based on the configuration of the maximum number of uplink subframes, with such H ARQ

acknowledgment timing being unchanged between initial and reconfigured UL-DL configurations. The maximum number of uplink subframes may be received in a SIB, and the minimum number of uplink subframes may be received in a bitmap identifying the minimum number of uplink subframes or determined from a second semi-static TDD UL-DL configuration through, for example, RRC signaling. At block 1510, the UE identifies one or more subframes within each frame transmitted using the initial UL-DL configuration as flexible subframes. The flexible subframes may be identified, for example, based on the minimum uplink subframes and the uplink subframes associated with the initial UL-DL. configuration. Finally, at block 1515, the UE receives a reconfiguration message indicating that the at least one flexible subframe is to be changed from an uplink subframe to a downlink subframe in the second frame. Such a reconfiguration message may be transmitted through physical layer (PHY ) signaling at the HE, and/or may be received through one or more pseudo-uplink grants having an invalid resource block allocation for the associated flexible subframe(s). In some examples, the invalid resource block allocation may be a RIV that exceeds a maximum value of an RIV for an uplink grant. . In such a manner, subframes in a TDD communication may be reconfigured dynamically, allowing for increased flexibility in uplink and downlink bandwidth for the UE.

|0090j FIG. 16 illustrates another method 1600 that may be carried out by a U E in a wireless communications system according to various embodiments. The method 1600 may, for example, be performed by a UE of FIG. 1. 3, 5, 10, or 12. or using any combination of the devices described for these figures. Initially, at block 1 05, the UE receives an initial uplink- downlink (UL-DL) configuration for TDD communication to the UE. At block 161.0, the UE receives a pseudo-uplink grant to the UE to reconfigure ihe UL-DL configuration to a different UL-DL configuration. In some examples, the pseudo-uplink grant comprises an invalid resource block allocation for at least one subframe of a TDD frame. Such an invalid resource block allocation may include a resource indication value (RIV) that exceeds a maximum value of an RIV for an uplink grant, in some examples, similarly as described above, the pseudo-uplink grant may include a first pseudo-uplink grant, tor a first of the flexible subframes of a TDD frame, and the base station may transmit a second pseudo- uplink grant for a second of the flexible subframes of the TDD frame, in such a manner, subframes in a TDD communication may be reconfigured dynamically, allowing for increased flexibility in uplink and downlink bandwidth with the particular UE. (00911 The detailed description set forth above in connection with the appended drawings describes exemplary embodiments and does not represent the only embodiments that may be implemented or tha are within the scope of the claims. The term "exemplary" used

throughout this description means "serving as an example, instance, or illustration/' and not ''preferred or "advantageous over other embodiments." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some

instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described embodiments.

(0092) Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

100931 The various illustrative blocks and modules described in connection with the disclosure herein maybe implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (PPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a

microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine, A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

(0094} The functions described herein may be implemented n hardware, software executed by a processor, firmware, or any combinatio thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of fractions are im Seme sited at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items prefaced by "at least one of indicates a disjunctive list such tha t, for example, a list of "at least one of A, B„ or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

{ΘΘ95} Computer-readable media includes both computer storage media and

communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEP OM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special- purpose computer, or a general-purpose or special -purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), o wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL. or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and b!u-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media, (0096) The previous description of the disclosure is provided to enable a person skilled in the art to raake or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein, may be applied to other variations without departing from the spirit or scope of the disclosure. Throughout this disclosure the term "example" or "exemplary" indicates an example or instance and does not imply or require any preference for the noted example. Thus, the disclosure is not to be iimited to the exampies and designs described herein but is to be accorded the widest scope consistent with the prmciples and novel features disclosed herein.

jO097j What is claimed is: