Dynamical time division duplex uplink and downlink configuration in a communications network

1. A user equipment (UE) operable to dynamically change an uplink/downlink (UL/DL) configuration in a communications network, the UE comprising one or more processors and memory configured to:

request a radio resource control (RRC) connection with an enhanced node B (eNode B);

communicate, to the eNode B, a UE Capability Information information element (IE) to indicate an enhanced interference mitigation and traffic adaptation (eIMTA) capability of the UE to support an eIMTA time duplex domain (TDD) UL/DL reconfiguration functionality;

receive, at the UE, eIMTA configuration information within a RRCConnectionSetup message or a RRCConnectionReconfiguration message, wherein the RRCConnectionSetup message or the RRCConnectionReconfiguration message includes an eIMTA Radio-Network Temporary Identifier (RNTI) and an UL/DL configuration indicator field index within an UL/DL reconfiguration physical downlink control channel (PDCCH) associated with a serving cell; and

decode, at the UE, the UL/DL reconfiguration PDCCH with a cyclic redundancy check (CRC) scrambled by the eIMTA-RNTI.

2. The UE of claim 1 , wherein the RRCConnectionSetup message or the RRCConnectionReconfiguration message includes:

a 2-bit or 3-bit UL/DL configuration indicator field index within the UL/DL reconfiguration PDCCH.

3. The UE of claim 1 , wherein the one or more processors and memory are further configured to:

determine UL/DL configuration information from a decoded UL/DL reconfiguration PDCCH based on the assigned indicator field index.

4. The UE of claim 1 , wherein the one or more processors and memory are further configured to monitor one common search space (CSS) on a Primary Cell (PCell) to receive the UL/DL reconfiguration PDCCH with CRC scrambled by the eIMTA-RNTI assigned for the UE.

5. The UE of claim 1 , wherein the one or more processors and memory are further configured to monitor one common search space (CSS) on a Primary Cell (PCell) to receive the UL/DL reconfiguration PDCCHs with CRCs scrambled by multiple different eIMTA-RNTIs separately, wherein each eIMTA-RNTI has a one-to-one mapping with a serving cell index.

6. The UE of claim 1 , wherein the one or more processors and memory are further configured to monitor a common search space (CSS) on each eIMTA-enabled serving cell to receive the UL/DL reconfiguration PDCCHs with CRC scrambled by one eIMTA-RNTI assigned for the UE.

7. The UE of claim 6 , wherein the one or more processors and memory are further configured to monitor a UE-group-common search space on a PDCCH on a Primary Cell (PCell) or each eIMTA-enabled serving cell to receive the UL/DL reconfiguration PDCCHs with CRC scrambled by different eIMTA-RNTIs assigned for the UE for each serving cell, wherein the control channel elements (CCEs) corresponding to PDCCH candidate m of the UE-group-common search space S k (L) are determined using:

L{(Y k +m′)mod └N CCE,k /L┘}+i,

where aggregation level Lε{1,2,4,8} is defined by a set of PDCCH candidates and, Y k is determined using:

Y k =( A·Y k−1 )mod D

where Y −1 =n RNTI ≠0, A=39827, D=65537 and k=└n s /2┘, n s is a slot number within a radio frame, and the RNTI value used for n RNTI is the eIMTA-RNTI assigned for UL/DL reconfiguration PDCCH transmission.

8. The UE of claim 7 , wherein m′=m when the monitoring UE is not configured with a carrier indicator field.

9. The UE of claim 7 , wherein

m′=m+M (L) ·n CI , where n CI is a carrier indicator field value,

m=0, . . . , M (L) −1, M (L) is a number of PDCCH candidates to monitor in a UE specific search space for aggregation level L, N CCE,k is a total number of CCEs in a control region of subframe k, and i=0, . . . , L−1 is a CCE index within a aggregation level L.

10. The UE of claim 3 , wherein the one or more processors and memeory are further configured to monitor the UE-group-common search space on an enhanced PDCCH (EPDCCH) on a PCell only when cross-carrier scheduling is configured or on each eIMTA-enabled serving cell when cross-carrier scheduling is not configured, to receive the UL/DL reconfiguration PDCCHs with CRC scrambled by multiple different eIMTA-RNTIs assigned for the UE, wherein enhanced control channel elements (ECCEs) corresponding to EPDCCH candidate m of a search space ES k (L) are given by:

L

⁢

{

(

Y

p

,

k

+

⌊

m

·

N

ECCE

,

p

,

k

L

·

M

p

(

L

)

⌋

+

b

)

⁢

mod

⁢

⌊

N

ECCE

,

p

,

k

/

L

⌋

}

+

i

,

Where Y p,k is defined below and i=0, . . . , L−1,

Y p,k =( A·Y p,k−1 )mod D

where aggregation level Lε{1,2,4,8,16,32} is defined by a set of EPDCCH candidates, Y p,k is variable ‘Y’ value in EPDCCH-physical resource block-set P of subframe k, and, m=0, 1, . . . M p (L) −1 is an ECCE index number within aggregation level L, N ECCE,p,k is a number of ECCEs in EPDCCH-PRB-set p of subframe k, M p (L) is a number of EPDCCH candidates to monitor at aggregation level L in EPDCCH-PRB-set P for a serving cell on which the EPDCCH is monitored, b=n CI if the UE is configured with a carrier indicator field for the serving cell on which EPDCCH is monitored, otherwise b=0; and n CI is the carrier indicator field value.

11. The UE of claim 1 , wherein the UL/DL reconfiguration PDCCH includes N TDD UL/DL Configuration Indicator (TCI) fields, where N is configured by the eNode B within an RRC signaling message for each eIMTA capable UE or N is determined using

N

=

⌊

L

format

⁢

⁢

Y

-

R

others

M

⌋

,

wherein L format Y is a payload size of an existing downlink control information (DCI) format Y before CRC attachment, R others ≧0 is a number of information bits used for selected functionalities, M is payload size for each UL/DL configuration indicator within UL/DL reconfiguration PDCCH, and format Y is mapped onto a common search space.

12. The UE of claim 11 , wherein the selected functionalities include Transmit Power Control (TPC) commands for physical uplink shared channel (PUSCH) transmission on flexible subframes.

13. The UE of claim 11 , wherein zero-padding information bits are appended to TDD UL/DL configuration indicator fields until a UL/DL reconfiguration PDCCH size is equal to a format Y size mapped onto the common search space.

14. An enhanced node B (eNode B) operable to dynamically change a time duplex domain (TDD) uplink/downlink (UL/DL) configuration in a communications network, the eNode B comprising one or more processors and memory configured to:

establish a radio resource control connection with a user equipment (UE);

receive, from the UE, a UE Capability Information information element (IE) to indicate an enhanced interference mitigation and traffic adaptation (eIMTA) capability of the UE;

determine support of eIMTA functionality by the UE based on the UE Capability Information IE; and

configure radio resource control (RRC) parameters for performing an eIMTA UL/DL reconfiguration of the UE, wherein the RRC parameters include an eIMTA Radio-Network Temporary Identifier (RNTI) and an UL/DL configuration indicator field index within an UL/DL reconfiguration physical downlink control channel (PDCCH) associated with a serving cell, and the UE is configured to decode the UL/DL reconfiguration PDCCH with a cyclic redundancy check (CRC) scrambled by the eIMTA-RNTI.

15. The eNode B of claim 14 , wherein the one or more processors and memory are further configured to communicate, to the UE, eIMTA parameters associated with a secondary cell (SCell) of the eNode B.

16. The eNode B of claim 14 , wherein the RRC parameters include an eIMTA radio network temporary identity (RNTI) of the UE and an indicator index.

17. A method for dynamically changing an uplink /downlink (UL/DL) ratio in a communications network, comprising:

requesting a radio resource control (RRC) connection with an enhanced node B (eNode B);

communicating, to the eNode B, a user equipment (UE) Capability Information message to indicate an enhanced interference mitigation and traffic adaptation (eIMTA) capability of the UE to support an eIMTA time duplex domain (TDD) UL/DL reconfiguration functionality; and

receiving, at the UE, eIMTA configuration information within a RRCConnectionSetup message or a RRCConnectionReconfiguration message, wherein the RRCConnectionSetup message or the RRCConnectionReconfiguration message includes an eIMTA Radio-Network Temporary Identifier (RNTI) and an UL/DL configuration indicator field index within an UL/DL reconfiguration physical downlink control channel (PDCCH) associated with a serving cell.

18. The method of claim 17 , wherein the RRCConnectionSetup message or the RRCConnectionReconfiguration message includes:

a 2-bit or 3-bit UL/DL configuration indicator field index within the UL/DL reconfiguration PDCCH.

19. The method of claim 17 , wherein a UL/DL reconfiguration physical downlink control channel (PDCCH) includes N TCI fields, where N is configured by the eNode B within an RRC signaling message for each eIMTA capable UE or N is determined using

N

=

⌊

L

format

⁢

⁢

Y

-

R

others

M

⌋

,

wherein is a L format y is a payload size of an existing downlink control information (DCI) format Y before CRC attachment, R others ≧0 is a number of information bits used for selected functionalities, M is a size of a target cell identifier (TCI) code word within the UL/DL reconfiguration PDCCH, and format Y is mapped onto a common search space.

20. The method of claim 19 , wherein the existing DCI format Y mapped onto the common search space is a DCI format 1 C.

21. The method of claim 19 , wherein the existing DCI format Y mapped onto the common search space is a DCI format 0/1A/3/3A.

22. The method of claim 19 , wherein the TCI code word size of M is 3 bits and each TCI code word is a different UL/DL configuration.

23. The method of claim 19 , wherein the UL/DL reconfiguration PDCCH mapped onto the common search space is configured to enable independent UL/DL configurations for each serving cell in a single carrier scenario, a coordinated multiple point (CoMP) scenario 3 , a CoMP scenario 4 , a carrier aggregation (CA) scenario, and a combination of a CA and CoMP scenario.

24. The method of claim 17 , further comprising:

receiving, at the UE, eIMTA configuration parameters and an indicator index associated with a secondary cell (SCell) of the UE; and

determining a UL/DL configuration for the SCell based on a received indicator index within a received UL/DL reconfiguration PDCCH.

25. The method of claim 19 , wherein a UL/DL configuration indicator field within a UL/DL reconfiguration PDCCH is 2 bits or 3 bits.

26. The method of claim 19 , further comprising:

transmitting the DCI format on all system information block 1 (SIB 1) DL subframes; and

determining, at a discontinuous reception (DRX) UE, an UL/DL configuration when the DRX UE is in a flexible subframe.