Flexible selection of timing advance control method for supplementary uplink connections

A method of operating a first base station in a wireless communication network that also includes a second base station, the method comprising:

• determining a first timing advance (TA) value usable to adjust a wireless communication device's transmission timing for an uplink (UL) connection with the first base station, wherein the UL connection is associated with a downlink (DL) connection between the wireless communication device and the first base station;
• receiving, from the second base station, a second TA value usable to adjust the wireless communication device's transmission timing for a supplementary UL (SUL) connection with the second base station, wherein the SUL connection is not associated with a DL connection between the wireless communication device and the second base station;
• and
• transmitting the first TA value and the second TA value to the wireless communication device via the DL connection.

A method of operating a wireless communication device in communication with first and second base stations in a wireless communication network, the method comprising:

• performing one or more transmissions on an uplink (UL) connection with the first base station, wherein the UL connection is associated with a downlink (DL) connection between the wireless communication device and the first base station;
• performing one or more transmissions on a supplementary UL (SUL) connection with the second base station, wherein the SUL connection is not associated with a DL connection between the wireless communication device and the second base station;
• and
• receiving, via the DL connection with the first base station, at least one timing advance (TA) value usable to adjust the wireless communication device's transmission timing for the UL connection and the SUL connection.

A method of operating a second base station in a wireless communication network that also includes a first base station, the method comprising:

• receiving one or more transmissions on a supplementary uplink (SUL) connection with a wireless communication device, wherein the SUL connection is:
• supplementary to an uplink (UL) connection between the first base station and the wireless communication device, and
• not associated with a DL connection with the wireless communication device;
• determining a second timing advance (TA) value usable to adjust the wireless communication device's transmission timing on the SUL connection;
• transmitting, to the first base station, the second TA value;
• and
• receiving, from the first base station, a message configuring the second base station to perform at least one corrective action with respect to the SUL connection.