| 主权项 |
1. A method for communication mode switching, comprising:
acquiring state information of a device-to-device link between a first user equipment (UE) and a second UE; and implementing a switching between a first communication mode and a second communication mode according to the state information of the device-to-device link between the first UE and the second UE, wherein the first UE and the second UE perform device-to-device communication under the first communication mode, and the first UE communicates with the second UE via a base station under the second communication mode; wherein the state information of the device-to-device link comprises a link quality parameter or a distance parameter, and wherein the implementing the switching between the first communication mode and the second communication mode according to the state information of the device-to-device link between the first UE and the second UE, comprises one of the following: switching from the first communication mode to the second communication mode, when the link quality parameter between the first UE and the second UE is less than a first preset threshold, or the distance parameter between the first UE and the second UE is greater than a second preset threshold; and switching from the second communication mode to the first communication mode, when the link quality parameter between the first UE and the second UE is greater than a third preset threshold, or the distance parameter between the first UE and the second UE is less than a fourth preset threshold, wherein, in a case of switching from the first communication mode to the second communication mode, the method further comprises: receiving, by the base station, packet data convergence protocol (PDCP) service data unit (SDU) data from the first UE, wherein the PDCP SDU data has been transmitted by the first UE to the second UE but no acknowledged feedback has been received or a not-acknowledged feedback has been received; receiving, by the base station, from the first UE, SDU data without a PDCP sequence number, a termination identifier packet and a first sequence number corresponding to the SDU data without the PDCP sequence number; numbering, by the base station, the SDU data without the PDCP sequence number until the termination identifier packet, according to the sequence number; transmitting, by the base station, the PDCP SDU data and the numbered SDU data to the second UE; and, wherein, in a case of switching from the second communication mode to the first communication mode, the method further comprises: transmitting, by the base station, PDCP SDU data to the first UE, wherein the PDCP SDU data has been transmitted by the base station to the second UE but no acknowledged feedback has been received or a not-acknowledged feedback has been received; transmitting, by the base station, to the first UE, SDU data without a PDCP sequence number, a termination identifier packet and a first sequence number corresponding to the SDU data without the PDCP sequence number, and the first UE numbers the SDU data without the PDCP sequence number until the termination identifier packet, according to the sequence number. |
