A method includes obtaining, by a first terminal device, second uplink data of a second terminal device, performing, by the first terminal device, joint coding processing on first uplink data of the first terminal device and on the second uplink data, where the performing the joint coding processing generates jointly coded data that is based on the first uplink data and the second uplink data, and transmitting, by the first terminal device, the first uplink data and the jointly coded data to a network device, where the first uplink data is transmitted to the network device separately from the jointly coded data. The first uplink data may be transmitted on a first transmission resource, and the jointly coded data to the network device may be transmitted on a second transmission resource different from the first transmission resource.