This application relates to the field of wireless communications, and in particular, to a communication method, an apparatus, and a system in a wireless communications system. In the method, a network device and a terminal device determine M resource element group bundles in a control resource set. The network device sends a control channel on resources corresponding to the M resource element group bundles. The terminal device detects the control channel on the resources corresponding to the M resource element group bundles, where M is greater than or equal to 1. The control resource set includes B resource element group resource element group bundles. By using the method, resource configuration efficiency in a communications system is improved.