For example, the candidate control channel 1 in the search space set 1 includes {CCE 2, CCE 3}, the candidate control channel 2 in the search space set 2 includes {CCE 2, CCE 3}, and the search space set 1 and the search space set 2 are associated with a same control-resource set. Because both the candidate control channel 1 and the candidate control channel 2 include {CCE 2, CCE 3}, resources of the candidate control channel 1 and the candidate control channel 2 overlap.
Optionally, if a plurality of candidate control channels in different search space sets associated with a same control-resource set include a same start CCE, resources of the plurality of candidate control channels including the same CCE overlap.
For example, the candidate control channel 1 in the search space set 1 includes {CCE 4, CCE 5, CCE 6, CCE 7}, the candidate control channel 2 in the search space set 2 includes {CCE 4, CCE 5}, and the search space set 1 and the search space set 2 are associated with a same control-resource set. Because both start CCEs of the candidate control channel 1 and the candidate control channel 2 are the CCE 4, resources of the candidate control channel 1 and the candidate control channel 2 overlap.
S202: The terminal device detects only at least one first candidate control channel in the at least two candidate control channels.
Optionally, a quantity of the at least one first candidate control channel is less than a quantity of the at least two candidate control channels.