Downlink signaling for adaptation of an uplink-downlink configuration in TDD communication systems

1. A method comprising:

transmitting, by an eNodeB (eNB) to a User Equipment (UE), a signal indicating a configuration of a period for the UE to receive one or more Physical Downlink Control CHannels (PDCCHs) in respective one or more Transmission Time Intervals (TTIs), each of the one or more PDCCHs conveying a same Downlink Control Information (DCI) format, the DCI format comprising at least one field indicating a first Time Division Duplexing (TDD) UpLink-DownLink (UL-DL) configuration in a first cell for DL data receptions or UL data transmissions from the UE, wherein a TDD UL-DL configuration includes ten TTIs each having a respective serial index from 0 to 9; and

transmitting, by the eNB to the UE, at least one PDCCH of the one or more PDCCHs, the at least one PDCCH configured to be used by the UE to decode a respective DCI format in a second cell;

wherein the period is a multiple of ten TTIs; and

wherein the one or more TTIs are in a last ten TTIs of the period.

2. The method of claim 1 , further comprising:

transmitting, by the eNB to the UE, a signal indicating a second TDD UL-DL configuration; and

transmitting, by the eNB to the UE, a signal indicating the one or more TTIs;

wherein all of the one or more TTIs support DL transmissions in the second TDD UL-DL configuration.

3. The method of claim 2 , wherein the one or more TTIs comprise a subset of {TTI#0, TTI#1, TTI#5, TTI#6} in the following table:

DL-to-UL

TDD UL-DL

Switch-

Config-

point

TTI number

uration

periodicity

0

1

2

3

4

5

6

7

8

9

0

5 ms

D

S

U

U

U

D

S

U

U

U

1

5 ms

D

S

U

U

D

D

S

U

U

D

2

5 ms

D

S

U

D

D

D

S

U

D

D

3

10 ms 

D

S

U

U

U

D

D

D

D

D

4

10 ms 

D

S

U

U

D

D

D

D

D

D

5

10 ms 

D

S

U

D

D

D

D

D

D

D

6

5 ms

D

S

U

U

U

D

S

U

U

D.

4. The method of claim 2 , wherein:

the UE receives each PDCCH and decodes the respective DCI format at least until the UE detects a valid DCI format, and

if the field in a detected DCI format indicates that a TTI in the first TDD UL-DL configuration supports UL transmissions and the TTI with the same serial index in the second TDD UL-DL configuration does not support UL transmissions, the DCI format is considered to be invalid.

5. The method of claim 1 , wherein the second cell uses Frequency Division Duplexing (FDD) and the eNB configures the one or more TTIs from all of the last ten TTIs or from eight predetermined TTIs of the last ten TTIs.

6. The method of claim 1 , further comprising:

transmitting, by the eNB to the UE, a signal indicating a second TDD UL-DL configuration;

transmitting, by the eNB to the UE, a first PDCCH conveying a first DCI format scheduling a data transmission to the UE in a first TTI; and

determining, by the eNB, acknowledgement information received in a second TTI of the second cell, wherein:

the second cell uses Frequency Division Duplexing (FDD),

the acknowledgement information includes acknowledgement information corresponding to data transmission in the first cell, including no data transmission, if the first TTI is a TTI that supports DL data transmission for the second TDD UL-DL configuration, and

the acknowledgement information does not include acknowledgement information corresponding to data transmission in the first cell if the first TTI is not a TTI that supports DL data transmission for the second TDD UL-DL configuration.

7. The method of claim 1 , wherein:

the DCI format comprises one or more fields indicating respective one or more TDD UL-DL configurations for DL data receptions or UL data transmissions from the UE in respective one or more cells; and

for each of the one or more cells, the eNB transmits to the UE a signal indicating a position for the respective field in the DCI format.

8. The method of claim 1 , further comprising:

transmitting to the UE a signal indicating a bitmap with six binary elements having a one-to-one mapping with {TTI#3, TTI#4, TTI#6, TTI#7, TTI#8, TTI#9} from the ten TTIs of a TDD UL-DL configuration,

wherein if a TTI from {TTI#3, TTI#4, TTI#6, TTI#7, TTI#8, TTI#9} supports UL transmission from the UE in the first TDD UL-DL configuration, the respective binary element indicates whether the UE applies a first Power Control (PC) process or a second PC process for an UL transmission.

9. An apparatus comprising an eNodeB (eNB), the eNB comprising:

a transmitter configured to communicate with a User Equipment (UE); and

a controller configured to:

initiate transmission to the UE of a signal indicating a configuration of a period for the UE to receive one or more Physical Downlink Control CHannels (PDCCHs) in respective one or more Transmission Time Intervals (TTIs), each of the one or more PDCCHs conveying a same Downlink Control Information (DCI) format, the DCI format comprising at least one field indicating a first Time Division Duplexing (TDD) UpLink-DownLink (UL-DL) configuration in a first cell for DL data receptions or UL data transmissions from the UE, wherein a TDD UL-DL configuration includes ten TTIs each having a respective serial index from 0 to 9; and

initiate transmission to the UE of at least one PDCCH of the one or more PDCCHs, the at least one PDCCH configured to be used by the UE to decode a respective DCI format in a second cell;

wherein the period is a multiple of ten TTIs; and

wherein the one or more TTIs are in a last ten TTIs of the period.

10. The apparatus of claim 9 , wherein the controller is further configured to:

initiate transmission to the UE of a signal indicating a second TDD UL-DL configuration; and

initiate transmission to the UE of a signal indicating the one or more TTIs; and

wherein all of the one or more TTIs support DL transmissions in the second TDD UL-DL configuration.

11. The apparatus of claim 10 , wherein the one or more TTIs comprise a subset of {TTI#0, TTI#1, TTI#5, TTI#6} in the following table:

DL-to-UL

TDD UL-DL

Switch-

Config-

point

TTI number

uration

periodicity

0

1

2

3

4

5

6

7

8

9

0

5 ms

D

S

U

U

U

D

S

U

U

U

1

5 ms

D

S

U

U

D

D

S

U

U

D

2

5 ms

D

S

U

D

D

D

S

U

D

D

3

10 ms 

D

S

U

U

U

D

D

D

D

D

4

10 ms 

D

S

U

U

D

D

D

D

D

D

5

10 ms 

D

S

U

D

D

D

D

D

D

D

6

5 ms

D

S

U

U

U

D

S

U

U

D.

12. The apparatus of claim 9 , wherein the controller is further configured to:

initiate transmission to the UE of a signal indicating a bitmap with six binary elements having a one-to-one mapping with {TTI#3, TTI#4, TTI#6, TTI#7, TTI#8, TTI#9} from the ten TTIs of a TDD UL-DL configuration,

wherein if a TTI from {TTI#3, TTI#4, TTI#6, TTI#7, TTI#8, TTI#9} supports UL transmission from the UE in the first TDD UL-DL configuration, the respective binary element indicates whether the UE applies a first Power Control (PC) process or a second PC process for an UL transmission.

13. The apparatus of claim 9 , wherein, when the second cell uses Frequency Division Duplexing (FDD), the eNB is operable to configure the one or more TTIs from all of the last ten TTIs or from eight predetermined TTIs of the last ten TTIs.

14. The apparatus of claim 9 , wherein:

the DCI format comprises one or more fields indicating respective one or more TDD UL-DL configurations for DL data receptions or UL data transmissions from the UE in respective one or more cells; and

for each of the one or more cells, the controller is configured to initiate transmission to the UE of a signal indicating a position for the respective field in the DCI format.

15. An apparatus comprising a User Equipment (UE), the UE comprising:

a receiver configured to:

receive, from an eNodeB (eNB), a signal indicating a configuration of a period to receive one or more Physical Downlink Control CHannels (PDCCHs) in respective one or more Transmission Time Intervals (TTIs), each of the one or more PDCCHs conveying a same Downlink Control Information (DCI) format, the DCI format comprising at least one field indicating a first Time Division Duplexing (TDD) UpLink-DownLink (UL-DL) configuration in a first cell for DL data receptions or UL data transmissions, wherein a TDD UL-DL configuration includes ten TTIs each having a respective serial index from 0 to 9; and

receive, from the eNB, at least one PDCCH of the one or more PDCCHs; and

a decoder configured to decode the DCI format conveyed by the at least one PDCCH in a second cell;

wherein the period is a multiple of ten TTIs; and

wherein the one or more TTIs are in a last ten TTIs of the period.

16. The apparatus of claim 15 , wherein the receiver is further configured to:

receive from the eNB a signal indicating a second TDD UL-DL configuration; and

receive from the eNB a signal indicating the one or more TTIs;

wherein all of the one or more TTIs support DL transmissions in the second TDD UL-DL configuration.

17. The apparatus of claim 16 , wherein the one or more TTIs comprise a subset of {TTI#0, TTI#1, TTI#5, TTI#6} in the following table:

DL-to-UL

TDD UL-DL

Switch-

Config-

point

TTI number

uration

periodicity

0

1

2

3

4

5

6

7

8

9

0

5 ms

D

S

U

U

U

D

S

U

U

U

1

5 ms

D

S

U

U

D

D

S

U

U

D

2

5 ms

D

S

U

D

D

D

S

U

D

D

3

10 ms 

D

S

U

U

U

D

D

D

D

D

4

10 ms 

D

S

U

U

D

D

D

D

D

D

5

10 ms 

D

S

U

D

D

D

D

D

D

D

6

5 ms

D

S

U

U

U

D

S

U

U

D.

18. The apparatus of claim 16 , wherein:

the receiver is further configured to receive signaling for multiple PDCCHs,

the decoder is further configured to decode the DCI format conveyed by each of the multiple PDCCHs at least until a valid DCI format is detected, and

if the field in a detected DCI format indicates that a TTI in the first TDD UL-DL configuration supports UL transmissions and the TTI with the same serial index in the second TDD UL-DL configuration does not support UL transmissions, the DCI format is considered to be invalid.

19. The apparatus of claim 15 , wherein:

the DCI format comprises one or more fields indicating respective one or more TDD UL-DL configurations for DL data receptions or UL data transmissions from the UE in respective one or more cells; and

for each of the one or more cells, the UE is configured to receive a signal indicating a position for the respective field in the DCI format.