Data transmission method and terminal

A method, comprising:

• receiving, by a second terminal, a first correspondence from a wireless access device that serves the second terminal or a core network device that serves the second terminal, wherein the first correspondence is between a plurality of D2D bearers usable to communicate between the second terminal and a first terminal and a plurality of quality of service (QoS) flows, and each QoS flow of the plurality of QoS flow corresponds to one D2D bearer of the plurality of D2D bearers, and in the correspondence one downlink D2D bearer uniquely corresponds to at least two QoS flows;
• sending, by the second terminal, the first correspondence to the first terminal;
• receiving, by the second terminal, a first uplink data packet sent by the first terminal using a first uplink device-to-device (D2D) bearer, wherein the plurality of D2D bearers comprises the first uplink D2D bearer, and the first uplink D2D bearer corresponds to a first uplink QoS flow required by the first uplink data packet in the first correspondence;
• querying a second correspondence based on the first uplink QoS flow required by the first uplink data packet, to identify an uplink radio bearer corresponding to the first uplink QoS flow;
• and
• sending, by the second terminal based on the second correspondence, a second uplink data packet to a wireless access device serving the second terminal, wherein the second correspondence comprises a correspondence between the first uplink QoS flow required by the first uplink data packet and an uplink radio bearer corresponding to the first QoS flow, and the second uplink data packet comprises a part or all of the first uplink data packet.

A second terminal, comprising:

• a processor;
• and
• a non-transitory memory having instructions that are executable by the processor, wherein the instructions comprise instructions for:
• receiving first information, wherein the first information comprises a correspondence between a plurality of downlink quality of service flows (QoS flows) and a plurality of downlink device-to-device (D2D) bearers, wherein the plurality of D2D bearers are usable to communicate between the second terminal and a first terminal, each QoS flow of the plurality of downlink QoS flows corresponds to a downlink D2D bearer of the plurality of downlink D2D bearers, and the first information is received by the second terminal from a wireless access device that serves the second terminal or a core network device that serves the second terminal;
• obtaining a downlink data packet carried on a first downlink QoS flow, wherein the downlink data packet carries an identification of the first downlink QoS flow;
• selecting a first downlink D2D bearer for the first downlink QoS flow by querying the received correspondence using the identification of the first downlink QoS flow, wherein the first downlink D2D bearer is comprised in the plurality of downlink D2D bearers and the first downlink QoS flow is comprised in the plurality of downlink QoS flows;
• and
• sending, to a first terminal, the downlink data packet on the first downlink D2D bearer corresponding to the first downlink QoS flow;
• and
• wherein in the correspondence one downlink D2D bearer uniquely corresponds to at least two QoS flows.

A second terminal, comprising:

• a processor;
• and
• a non-transitory memory having instructions stored thereon that are executable by the processor, wherein the instructions comprise instructions for:
• receiving a first correspondence from a wireless access device that serves the second terminal or a core network device that serves the second terminal, wherein the first correspondence is between a plurality of D2D bearers usable to communicate between the second terminal and a first terminal and a plurality of quality of service (QoS) flows, and each QoS flow of the plurality of QoS flow corresponds to one D2D bearer of the plurality of D2D bearers, and in the first correspondence one downlink D2D bearer uniquely corresponds to at least two QoS flows;
• sending, by the second terminal, the first correspondence to the first terminal;
• receiving a first uplink data packet sent by the first terminal using a first uplink device-to-device (D2D) bearer, wherein the plurality of D2D bearers comprises the first uplink D2D bearer, and the first uplink D2D bearer corresponds to a first uplink QoS flow required by the first uplink data packet in the first correspondence;
• querying a second correspondence based on the first uplink QoS flow required by the first uplink data packet, to identify an uplink radio bearer corresponding to the first uplink QoS flow;
• and
• sending, based on the second correspondence, a second uplink data packet to a wireless access device serving the second terminal, wherein the second uplink data packet comprises a part or all of the first uplink data packet, and the second correspondence comprises a correspondence between the first uplink QoS flow required by the first uplink data packet and an uplink radio bearer corresponding to the first uplink QoS flow.