Preconfigured uplink resources—configuration for TA validity in entire cell
Systems and methods for determining timing advance (TA) validity are disclosed. In some embodiments, systems and methods are disclosed herein in which a wireless device implicitly considers a TA to be valid in a full cell when no TA validation mechanisms are explicitly configured. In other embodiments, systems and methods are disclosed herein in which a timer serves a dual purpose. If the timer is set to infinity, a wireless device will always consider a TA to be valid within a given cell, and at the same time will disable other TA validation mechanisms. Otherwise, the wireless device will interpret the timer as indicating for how long the TA value that the wireless device possesses is considered to be valid. Benefits of the solutions described herein include reducing signaling bits in the configuration and avoiding the possibility of conflicting configurations.
1. A method performed by a wireless device of a cellular communications system to determine timing advance, TA, validity, the method comprising:
obtaining a TA for a cell of the cellular communications system;
determining that a configuration comprising signaling bits activating a TA validation mechanism of a predefined set of TA validation mechanisms has not been received from a network node; and
responsive to determining that the configuration activating the TA validation mechanism of the predefined set of validation mechanisms has not been received, determining that the TA is valid for an entirety of the cell, wherein the TA validation mechanism is one of a Time Alignment Timer for idle mode, serving cell Reference Signal Received Power (RSRP) or Narrowband RSRP (NSRP) changes.
2. The method of claim 1 , wherein the predefined set of TA validation mechanisms comprises one or more optional TA validation mechanisms.
3. The method of claim 1 , further comprising performing one or more uplink transmissions using the TA.
4. The method of claim 3 , wherein performing the one or more uplink transmissions using the TA comprises performing the one or more uplink transmissions on one or more preconfigured uplink resources.
5. A wireless device of a cellular communications system enabled to determine timing advance, TA, validity, the wireless device comprising processing circuitry coupled to a memory, the processing circuitry configured to:
obtain a TA for a cell of the cellular communications system;
determine that a configuration comprising signaling bits activating a TA validation mechanism of a predefined set of TA validation mechanisms has not been received from a network node; and
responsive to determining that the configuration activating the TA validation mechanism of the predefined set of TA validation mechanisms has not been received, determine that the TA is valid for an entirety of the cell, wherein the TA validation mechanism is one of a Time Alignment Timer for idle mode, serving cell Reference Signal Received Power (RSRP) or Narrowband RSRP (NSRP) changes.
6. The wireless device of claim 5 , wherein the predefined set of TA validation mechanisms comprises one or more optional TA validation mechanisms.
7. The wireless device of claim 5 , wherein the processing circuitry is further configured to cause the wireless device to perform one or more uplink transmissions using the TA.
8. The wireless device of claim 7 , wherein, in order to perform the one or more uplink transmissions using the TA, the processing circuitry is further configured to cause the wireless device to perform the one or more uplink transmissions on one or more preconfigured uplink resources.
9. A method performed by a wireless device of a cellular communications system to determine timing advance, TA, validity, the method comprising:
obtaining a TA for a cell;
receiving one or more configurations comprising signaling bits corresponding to one or more activations of TA validation mechanisms;
receiving a first timer;
determining that the first timer is set to infinity; and
responsive to determining that the first timer is set to infinity:
determining that the TA is valid for an entirety of the cell;
responsive to determining that the TA is valid for the entirety of the cell, disabling the one or more TA validation mechanisms; and
receiving a second timer;
determining that the second timer is not set to infinity; and
responsive to determining that the second timer is not set to infinity, interpreting the second timer as an indication of how long the TA is considered valid, wherein the TA validation mechanism is one of a Time Alignment Timer for idle mode, serving cell Reference Signal Received Power (RSRP) or Narrowband RSRP (NSRP) changes.
10. The method of claim 9 , wherein the one or more TA validation mechanisms comprises one or more optional TA validation mechanisms.
11. The method of claim 9 , wherein the first timer comprises a Preconfigured Uplink Resources, PUR, Time Alignment Timer.
12. The method of claim 9 further comprising, responsive to determining that the first timer is set to infinity, performing one or more uplink transmissions using the TA.
13. The method of claim 12 , wherein performing the one or more uplink transmissions using the TA comprises performing the one or more uplink transmissions using the TA on one or more PUR resources.
14. The method of claim 9 , further comprising, responsive to determining that the second timer is not set to infinity, performing one or more uplink transmissions using the TA while the second timer is running and the TA is valid as determined by a User Equipment, UE, using the one or more TA validation mechanisms.
15. The method of claim 14 , wherein performing the one or more uplink transmissions using the TA comprises performing the one or more uplink transmissions using the TA on one or more PUR resources.