Timing advance and processing capabilities in a reduced latency system
A method and apparatus are described herein for handling reduced available processing time in systems configured to reduce latency such as systems using configurable transmission time intervals (TTIs) or short TTIs (sTTIs) and a processing capability (PC). A wireless transmit/receive unit (WTRU) may be configured to use a PC. The WTRU may receive a TTI configuration. The WTRU may determine the PC of the WTRU. The PC may be determined based on at least one of the TTI configuration and a processing criteria. The WTRU may then transmit a report of the determined PC. The report may be transmitted to and eNB. The PC may be a timeline, and the timeline may be reported as a number of time units, wherein a time unit is at least one of a symbol, a TTI, a time sample, and a set of time samples.
1. A method for use in a wireless transmit/receive unit (WTRU) for using a processing capability (PC), the method comprising:
receiving transmission time interval (TTI) configuration information;
transmitting a WTRU capabilities message, including information indicating the PC of the WTRU, wherein the PC is associated with a minimum processing time and a maximum timing advance (TA) value, wherein the maximum TA value is associated with the minimum processing time, and wherein the minimum processing time is represented as a number of time units;
receiving a TA value, wherein the TA value is less than or equal to the maximum TA value; and
transmitting user data using a TTI length and the TA value, wherein the TTI length is based on the received TTI configuration information.
2. The method of claim 1 , wherein a time unit is at least one of a symbol, a TTI, a time sample, and a set of time samples.
3. The method of claim 1 , wherein the TTI configuration information indicates at least a number of symbols for the TTI length.
4. The method of claim 1 , wherein the TTI configuration information indicates at least a number of timeslots for the TTI length.
5. The method of claim 1 , wherein the TTI configuration information indicates at least a subcarrier spacing for the TTI length.
6. The method of claim 1 , wherein the information indicating the PC is transmitted as part of a set of information indicating PCs.
7. The method of claim 1 , wherein the number of time units is a number between a first time unit and a second time unit, wherein user data is transmitted during the first time unit.
8. The method of claim 7 , wherein hybrid-automatic repeat requests (HARQ) feedback is received during the second time unit.
9. A wireless transmit/receive unit (WTRU) configured to use a processing capability (PC), the WTRU comprising:
a receiver configured to receive transmission time interval (TTI) configuration information;
a transmitter configured to transmit a WTRU capabilities message, including information indicating the PC of the WTRU, wherein the PC is associated with a minimum processing time and a maximum timing advance (TA) value, wherein the maximum TA value is associated with the minimum processing time, and wherein the minimum processing time is represented as a number of time units;
the receiver configured to receive a TA value, wherein the TA value is less than or equal to the maximum TA value; and
the transmitter configured to transmit user data using a TTI length and the TA value, wherein the TTI length is based on the received TTI configuration information.
10. The WTRU of claim 9 , wherein a time unit is at least one of a symbol, a TTI, a time sample, and a set of time samples.
11. The WTRU of claim 9 , wherein the TTI configuration information indicates at least a number of symbols for the TTI length.
12. The WTRU of claim 9 , wherein the TTI configuration information indicates at least a number of timeslots for the TTI length.
13. The WTRU of claim 9 , wherein the TTI configuration information indicates at least a subcarrier spacing for the TTI length.
14. The WTRU of claim 9 , wherein the information indicating the PC is transmitted as part of a set of information indicating PCs.
15. The WTRU of claim 9 , wherein the number of time units is a number between a first time unit and a second time unit, wherein user data is transmitted during the first time unit.
16. The WTRU of claim 15 , wherein hybrid-automatic repeat requests (HARQ) feedback is received during the second time unit.
17. A method for use in a base station for using a processing capability (PC), the method comprising:
transmitting a transmission time interval (TTI) configuration information;
receiving a wireless transmit/receive unit (WTRU) capabilities message including determined information indicating the PC of a WTRU, wherein the PC is associated with a minimum processing time and a maximum timing advance (TA) value, wherein the maximum TA value is associated with the minimum processing time, and wherein the minimum processing time is represented as a number of time units;
transmitting a TA value, wherein the TA value is less than or equal to the maximum TA value; and
receiving user data using a TTI length and the TA value, wherein the TTI length is based on the transmitted TTI configuration information.
18. The method of claim 17 , wherein a time unit is at least one of a symbol, a TTI, a time sample, and a set of time samples.
19. The method of claim 17 , the TTI configuration information indicates at least one of a number of symbols, a number of timeslots and a subcarrier spacing for the TTI length.
20. The method of claim 17 , wherein the information indicating the PC is received as part of a set of information indicating PCs.
21. The method of claim 17 , wherein the number of time units is a number between a first time unit and a second time unit, wherein user data is received during the first time unit.
22. The method of claim 21 , wherein hybrid-automatic repeat requests (HARQ) feedback is transmitted during the second time unit.