In another possible manner, the serial number of the first transmission unit included in the k-th control resource subset is k+r*K, the value of k is 0 to K?1, and the value of r is 0 to R?1. Taking K=4, N=4, and R=3 as an example, the serial numbers of the CCEs included in the control resource subset 0 are 0, 4, and 8; the serial numbers of the CCEs included in the control resource subset 1 are 1, 5, and 9; the serial numbers of the CCEs included in the control resource subset 2 are 2, 6, and 10; the serial numbers of the CCEs included in the control resource subset 3 are 3, 7, and 11, that is, the CCEs are interleaved and mapped on the subbands. As shown in FIG. 9, the REG groups in each control resource subset are numbered. Optionally, the serial numbers of the REG groups included in CCE0 are 0, 3 and 6, the serial numbers of the REG groups included in CCE1 are 9, 12 and 15, the serial numbers of the REG groups included in CCE2 are 18, 21 and 24, the serial numbers of the REG groups included in CCE3 are 27, 30 and 33, the serial numbers of the REG groups included in CCE4 are 1, 4 and 7, the serial numbers of the REG groups included in CCE5 are 10, 13 and 16, and the serial numbers of the REG groups included in CCE6 are 19, 22 and 25, the serial numbers of the REG groups included in CCE7 are 28, 31 and 34, the serial numbers of the REG groups included in CCE8 are 2, 5 and 8, the serial numbers of REG groups included in CCE9 are 11, 14 and 17, and the serial numbers of the REG groups included in CCE10 are 20, 23 and 26, and the serial numbers of the REG groups included in CCE11 are 29, 32 and 35. It is assumed that a PDCCH is mapped to 8 CCEs, for example, the PDCCH is mapped to the first two CCEs of each control resource subset, then the serial numbers of the CCEs occupied by the PDCCH are 0, 1, 2, 3, 4, 5, 6, 7, and optionally, the mapping sequence of the PDCCH is as shown in FIG. 9. That is, when the PDCCH is mapped to CCEs, the first CCE in each control resource subset is occupied first, and then the second CCE in each control resource subset is occupied. Optionally, the mapping sequence of the PDCCH may also be another sequence, for example, the sequence of the serial numbers of the CCEs occupied by the PDCCH is 0, 4, 1, 5, 2, 6, 3, 7, or, for example, the sequence of the serial numbers of the REG groups included in the CCEs occupied by the PDCCH is 0, 1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 16, 18, 19, 21, 22, 24, 25, 27, 28, 30, 31, 33, 34.