Technique for providing multiple Radio Access Network connectivity to terminal device

A method of providing multiple connectivity to a terminal device via at least a first Radio Access Network (RAN) entity and a second RAN entity, wherein the first RAN entity serves as a control plane anchor, the method comprising:

• setting up, at the second RAN entity and in response to being triggered by the first RAN entity, a split bearer on a user plane;
• setting up a flow control transmitter entity for a flow control link between a Packet Data Convergence Protocol (PDCP) entity of the second RAN entity and a Radio Link Control (RLC) entity of the first RAN entity,
• wherein the split bearer comprises at least:
• a first bearer leg from the second RAN entity to the terminal device without going through the first RAN entity;
• and
• a second bearer leg from the second RAN entity via the first RAN entity to the terminal device.

A Radio Access Network (RAN) entity for a system capable of providing multiple connectivity to a terminal device via at least a first RAN entity and a second RAN entity, wherein the first RAN entity serves as a control plane anchor, the RAN entity being the first RAN entity and comprising:

• processing circuitry;
• memory containing instructions executable by the processing circuitry whereby the RAN entity is operative to:
• evaluate whether to set up a split bearer at the first RAN entity or at the second RAN entity;
• and
• decide to set up the split bearer at the second RAN entity;
• trigger the second RAN entity to set up the split bearer on a user plane;
• trigger setup of the split bearer at the terminal device;
• and
• trigger setup of a flow control receiver entity for a flow control link between a Radio Link Control (RLC) entity of the first RAN entity and a Packet Data Convergence Protocol (PDCP) entity of the second RAN entity,
• wherein the split bearer comprises at least:
• a first bearer leg from the second RAN entity via the first RAN entity to the terminal device;
• and
• a second bearer leg from the second RAN entity to the terminal device without going through the first RAN entity.

A Radio Access Network (RAN) entity for a system capable of providing multiple connectivity to a terminal device via at least a first RAN entity and a second RAN entity, wherein the first RAN entity serves as control plane anchor, the RAN entity being the second RAN entity and comprising:

• processing circuitry;
• memory containing instructions executable by the processing circuitry whereby the RAN entity is operative to:
• set up, at the second RAN entity and in response to being triggered by the first RAN entity, a split bearer on a user plane;
• set up a flow control transmitter entity for a flow control link between a Packet Data Convergence Protocol (PDCP) entity of the second RAN entity and a Radio Link Control (RLC) entity of the first RAN entity,
• wherein the split bearer comprises at least:
• a first bearer leg from the second RAN entity to the terminal device without going through the first RAN entity;
• and
• a second bearer leg from the second RAN entity via the first RAN entity to the terminal device.