Communication methods and devices for sidelink

A communication method for a sidelink (SL), comprising:

• sending, by a second terminal device, a first message to a first terminal device;
• receiving, by the second terminal device, first feedback information, which is sent by the first terminal device using a first transmission resource, wherein the first feedback information is feedback information in response to the first message, a time unit in which the first transmission resource is located is not used for transmitting data by the first terminal device to at least one third terminal device or the second terminal device, and the first terminal device, the second terminal device, and the at least one third terminal device belong to a first group, wherein identifier information of the first terminal device is used for the first terminal device to determine the first transmission resource from a first transmission resource set, wherein the identifier information comprises a member identifier of the first terminal device in the first group;
• and
• sending, by the second terminal device, index information to the first terminal device, wherein the index information is used to determine an index of the first transmission resource.