Timing advance enhancements for cellular communications
A disclosed example method involves, when a device is operating in a stationary mode and before a need of the device to communicate data, determining whether a stored timing advance is valid. When the stored timing advance is not valid, a valid timing advance is determined before the need of the device to communicate the data.
1. A method comprising:
transmitting, from a network, an indication permitting devices to operate in a stationary mode; and
in response to transmitting the indication, receiving, from a device, a first message indicating an initial access by the device to transmit uplink data to the network, wherein the first message comprises uplink data transmitted from the device, and the device has not performed a random access transmission associated with the initial access prior to sending the first message, wherein the first message is transmitted from the device using a valid timing advance (TA) value stored at the device, and the TA value is determined to be valid based on whether a pre-determined time interval has elapsed since the TA value was stored or since the stored TA value has been used for a last successful data transfer.
2. The method of claim 1 , wherein determining that the stored TA value is valid further includes at least one of: determining whether a pre-determined number of attempts to access the network have failed using the stored TA value, or whether the device has a current location different from an original location where the stored TA value was determined for a previous data transfer.
3. The method of claim 1 , wherein the device performs a random access transmission over a contention-based RACH to determine a valid TA value in response to the device determining that the TA value stored at the device is invalid.
4. The method of claim 3 , wherein the device performs the random access transmission over the contention-based RACH using a zero TA value.
5. The method of claim 1 , wherein the TA value stored at the device is non-zero.
6. The method of claim 1 , wherein the indication permitting devices to operate in a stationary mode is transmitted in a broadcast message.
7. A network node, comprising:
a memory; and
at least one hardware processor communicatively coupled with the memory and configured to:
transmit, from the network node, an indication permitting devices to operate in a stationary mode; and
in response to transmitting the indication, receive, from a device, a first message indicating an initial access by the device to transmit uplink data to the network, wherein the first message comprises uplink data transmitted from the device, and the device has not performed a random access transmission associated with the initial access prior to sending the first message, wherein the first message is transmitted from the device using a valid timing advance (TA) value stored at the device, and the TA value is determined to be valid based on whether a pre-determined time interval has elapsed since the TA value was stored or since the stored TA value has been used for a last successful data transfer.
8. The device of claim 7 , wherein determining that the stored TA value is valid further includes at least one of: determining whether a pre-determined number of attempts to access the network node have failed using the stored TA value, or whether the device has a current location different from an original location where the stored TA value was determined for a previous data transfer.
9. The device of claim 7 , wherein the device performs a random access transmission over a contention-based RACH to determine a valid TA value in response to the device determining that the TA value stored at the device is invalid.
10. The device of claim 9 , wherein the device performs the random access transmission over the contention-based RACH using a zero TA value.
11. The device of claim 7 , wherein the TA value stored at the device is non-zero.
12. The device of claim 7 , wherein the indication permitting devices to operate in a stationary mode is transmitted in a broadcast message.
13. A non-transitory computer-readable medium containing instructions which, when executed, cause a network node to perform operations comprising:
transmitting, from the network node, an indication permitting devices to operate in a stationary mode; and
in response to transmitting the indication, receiving, from a device, a first message indicating an initial access by the device to transmit uplink data to the network, wherein the first message comprises uplink data transmitted from the device, and the device has not performed a random access transmission associated with the initial access prior to sending the first message, wherein the first message is transmitted from the device using a valid timing advance (TA) value stored at the device, and the TA value is determined to be valid based on whether a pre-determined time interval has elapsed since the TA value was stored or since the stored TA value has been used for a last successful data transfer.
14. The non-transitory computer-readable medium of claim 13 , wherein determining that the stored TA value is valid further includes at least one of: determining whether a pre-determined number of attempts to access the network node have failed using the stored TA value, or whether the device has a current location different from an original location where the stored TA value was determined for a previous data transfer.
15. The non-transitory computer-readable medium of claim 13 , wherein the device performs a random access transmission over a contention-based RACH to determine a valid TA value in response to the device determining that the TA value stored at the device is invalid.
16. The non-transitory computer-readable medium of claim 15 , wherein the device performs the random access transmission over the contention-based RACH using a zero TA value.
17. The non-transitory computer-readable medium of claim 13 , wherein the TA value stored at the device is non-zero.