Semi-static and dynamic TDD configuration for 5G-NR
TDD configuration may be dynamically and/or semi-statically signaled to user equipment devices by a base station. Semi-static TDD configuration may include: an initial portion for downlink transmission; a flexible portion; and a terminal portion for uplink transmission. TDD structure of the flexible portion may be determined later by transmission of dynamic physical layer configuration information such as downlink control information (DCI) and/or slot format indicator (SFI). (The SFI may be included in a group common PDCCH of a slot.) The downlink portion and/or the uplink portion may include subsets whose nominal transmit direction is subject to override by transmission of dynamic physical layer configuration information.
1. An apparatus configured for implementation in a user equipment device, the apparatus comprising:
one or more processing elements, wherein the one or more processing elements are configured to:
receive TDD configuration information, wherein the TDD configuration information includes parameters that define a semi-static TDD configuration for a frame structure, wherein the parameters include:
a frame length specifying a duration of the frame structure;
a first length specifying a duration of a downlink portion of the frame structure, wherein the downlink portion occupies an initial position within the frame structure, wherein said first length is specified by the semi-static TDD configuration in terms of slots and symbols,
wherein a slot is a specified number of symbols in length; and
a second length specifying a duration of an uplink portion of the frame structure, wherein the uplink portion occupies a terminal position within the frame structure, wherein said second length is specified by the semi-static TDD configuration in terms of slots and symbols;
wherein an intermediate portion of the frame structure occurs after the downlink portion and before the uplink portion, wherein the intermediate portion includes a number of flexible symbols useable for an uplink or downlink direction, wherein a respective direction for each respective symbol of the number of flexible symbols is not determined by the TDD configuration information; and
in response to receiving the TDD configuration information, perform TDD operations including:
receiving downlink data according to the TDD configuration information; and
transmitting uplink data according to the TDD configuration information.
2. The apparatus of claim 1 , wherein the one or more processing elements are further configured to:
receive one or more physical layer signals that dynamically determine a TDD structure of the intermediate portion; and
perform TDD operation over the intermediate portion based on the dynamically determined TDD structure.
3. The apparatus of claim 1 , wherein the one or more processing elements are further configured to:
perform TDD operation for each frame in a sequence of frames based on the semi-static TDD configuration, wherein, for each of the frames of the sequence, a TDD structure of the intermediate portion of the frame is determined by corresponding dynamic configuration information provided in one or more slots of the frame.
4. The apparatus of claim 1 ,
wherein the downlink portion includes an initial subportion and a following subportion;
wherein the initial subportion is configured for downlink transfer with no possibility of dynamic override to different TDD status;
wherein the following subportion is configured for downlink transfer with possibility of dynamic override to different TDD status.
5. The apparatus of claim 1 , wherein the TDD configuration information is received from a first base station that operates on a first frequency channel, wherein the one or more processing elements are further configured to:
apply a time shift to slots of a current radio frame, wherein the time shift depends on an indicator of a TDD configuration being used by a second base station that operates on a second frequency channel that is frequency adjacent to the first frequency channel, wherein, after the time shift, a current semi-static TDD configuration of radio frame conforms to a TDD configuration of 3GPP LTE.
6. The apparatus of claim 1 , wherein said flexible symbols are in a transition slot;
wherein symbols of the transition slot that are neither part of the uplink portion nor the downlink portion are gap symbols.
7. The apparatus of claim 6 , wherein the symbols of the downlink portion and the symbols of the uplink portion are configured to achieve agreement with a TDD configuration of 3GPP LTE.
8. The apparatus of claim 1 , wherein the TDD configuration information does not conflict with transmission direction indicated by dynamic downlink control information (DCI).
9. The apparatus of claim 1 , wherein the TDD configuration information further indicates cancellation of one or more periodic transmissions configured by RRC.
10. The apparatus of claim 1 , wherein the one or more processing elements are further configured to:
receive downlink control information (DCI) useable to determine a dynamic TDD structure for at least a portion of a slot, wherein the dynamic TDD structure overrides the semi-static TDD configuration of the intermediate portion without possibility of overriding the uplink and downlink portions of the frame structure specified by the TDD configuration information.
11. A method for operating a user equipment device, the method comprising:
receiving, by a radio of the user equipment device, TDD configuration information, wherein the TDD configuration information includes parameters that define a semi-static TDD configuration for a frame structure, wherein the parameters include:
a frame length specifying a duration of the frame structure;
a first length specifying a duration of a downlink portion of the frame structure, wherein the downlink portion occupies an initial position within the frame structure, wherein said first length is specified by the semi-static TDD configuration in terms of whole slots and symbols, wherein a slot is a specified number of symbols in length; and
a second length specifying a duration of an uplink portion of the frame structure, wherein the uplink portion occupies a terminal position within the frame structure, wherein said second length is specified by the semi-static TDD configuration in terms of whole slots and symbols;
wherein an intermediate portion of the frame structure occurs after the downlink portion and before the uplink portion, wherein the intermediate portion includes a number of flexible symbols useable for an uplink or downlink direction, wherein a respective direction for each respective symbol of the number of flexible symbols is not determined by the TDD configuration information; and
in response to receiving the TDD configuration information, perform TDD operations including:
receiving, by the radio, downlink data according to the TDD configuration information; and
transmitting, by the radio, uplink data according to the TDD configuration information.
12. The method of claim 11 , further comprising:
receiving one or more physical layer signals that dynamically determine a TDD structure of the intermediate portion; and
performing TDD operation over the intermediate portion based on the dynamically determined TDD structure.
13. The method of claim 11 , the method further comprising:
performing TDD operation for each frame in a sequence of frames based on the semi-static TDD configuration, wherein, for each of the frames of the sequence, a TDD structure of the intermediate portion of the frame is determined by corresponding dynamic configuration information provided in one or more slots of the frame.
14. The method of claim 11 ,
wherein the downlink portion includes an initial subportion and a following subportion;
wherein the initial subportion is configured for downlink transfer with no possibility of dynamic override to different TDD status;
wherein the following subportion is configured for downlink transfer with possibility of dynamic override to different TDD status.
15. A user equipment device (UE), comprising:
a radio;
one or more processing elements coupled to the radio, wherein the one or more processing elements are configured to:
receive, by the radio of the user equipment device, TDD configuration information, wherein the TDD configuration information includes parameters that define a semi-static TDD configuration for a frame structure, wherein the parameters include:
a frame length specifying a duration of the frame structure;
a first length specifying a duration of a downlink portion of the frame structure, wherein the downlink portion occupies an initial position within the frame structure, wherein said first length is specified by the semi-static TDD configuration in terms of slots and symbols,
wherein a slot is a specified number of symbols in length; and
a second length specifying a duration of an uplink portion of the frame structure, wherein the uplink portion occupies a terminal position within the frame structure, wherein said second length is specified by the semi-static TDD configuration in terms of slots and symbols;
wherein an intermediate portion of the frame structure occurs after the downlink portion and before the uplink portion, wherein the intermediate portion includes a number of flexible symbols useable for an uplink or downlink direction, wherein a respective direction for each respective symbol of the number of flexible symbols is not determined by the TDD configuration information; and
in response to receiving the TDD configuration information, perform TDD operations including:
receiving, by the radio, downlink data according to the TDD configuration information; and
transmitting, by the radio, uplink data according to the TDD configuration information.
16. The UE of claim 15 , wherein the user equipment device receives the TDD configuration information from a first base station that operates on a first frequency channel, wherein the one or more processing elements are further configured to:
apply a time shift to slots of a current radio frame, wherein the time shift depends on an indicator of a TDD configuration being used by a second base station that operates on a second frequency channel that is frequency adjacent to the first frequency channel, wherein, after the time shift, a current semi-static TDD configuration of radio frame conforms to a TDD configuration of 3GPP LTE.
17. The UE of claim 15 , wherein said flexible symbols are in a transition slot;
wherein symbols of the transition slot that are neither part of the uplink portion nor the downlink portion are gap symbols;
wherein the symbols of the downlink portion and the symbols of the uplink portion are configured to achieve agreement with a TDD configuration of 3GPP LTE.
18. The UE of claim 15 , wherein the TDD configuration information does not conflict with transmission direction indicated by dynamic downlink control information (DCI).
19. The UE of claim 15 , wherein the TDD configuration information further indicates cancellation of one or more periodic RRC transmissions.
20. The UE of claim 15 , wherein the one or more processing elements are further configured to:
receive downlink control information (DCI) useable to determine a dynamic TDD structure for at least a portion of a slot, wherein the dynamic TDD structure overrides the semi-static TDD configuration of the intermediate portion without possibility of overriding the uplink and downlink portions of the frame structure specified by the TDD configuration information.