An information transmission method performed by a network device, the method comprising: • determining one or more physical hybrid automatic repeat request indicator channel PHICH resources of a first subframe, wherein the one or more physical hybrid automatic repeat request indicator channel PHICH resources indicate a quantity of orthogonal frequency division multiplexing OFDM symbols comprised in a second subframe on an unlicensed carrier (step 201), wherein the determining the one or more PHICH resources comprises: determining a number n _ u PHICH group of a PHICH group of the one or more PHICH resources according to a formula n _ u PHICH group = mod Cell _ ID, N PHICH group, n _ u PHICH group = mod F Cell _ ID, N PHICH group, or n _ u PHICH group = mod F Cell _ ID, Operator _ ID, N PHICH group; and determining a number n _ u PHICH seq of an orthogonal sequence in the PHICH group n _ u PHICH group of the one or more PHICH resources according to a formula n _ u PHICH seq = mod Cell _ ID, N PHICH seq, n _ u PHICH seq = mod F Cell _ ID, N PHICH seq, or n _ u PHICH seq = mod F Cell _ ID, Operator _ ID, N PHICH Seq, wherein mod() is a mod function, Cell_ID is a cell identity, F ( Cell_ID) is a function in which the cell identity is an independent variable, Operator _ ID is an operator identifier, F ( Cell _ ID, Operator _ ID) is a function in which the cell identity and the operator identifier are independent variables, N PHICH group is a quantity of PHICH groups, and N PHICH seq is a quantity of orthogonal sequences in each PHICH group; • sending the first subframe and the second subframe to a user equipment, wherein the second subframe is sent before the first subframe, the first subframe comprises M orthogonal frequency division multiplexing OFDM symbols, the second subframe comprises N OFDM symbols, M and N are positive integers, and M ≥ N (step 202). • determining one or more physical hybrid automatic repeat request indicator channel PHICH resources of a first subframe, wherein the one or more physical hybrid automatic repeat request indicator channel PHICH resources indicate a quantity of orthogonal frequency division multiplexing OFDM symbols comprised in a second subframe on an unlicensed carrier (step 201), wherein the determining the one or more PHICH resources comprises: determining a number n _ u PHICH group of a PHICH group of the one or more PHICH resources according to a formula n _ u PHICH group = mod Cell _ ID, N PHICH group, n _ u PHICH group = mod F Cell _ ID, N PHICH group, or n _ u PHICH group = mod F Cell _ ID, Operator _ ID, N PHICH group; and determining a number n _ u PHICH seq of an orthogonal sequence in the PHICH group n _ u PHICH group of the one or more PHICH resources according to a formula n _ u PHICH seq = mod Cell _ ID, N PHICH seq, n _ u PHICH seq = mod F Cell _ ID, N PHICH seq, or n _ u PHICH seq = mod F Cell _ ID, Operator _ ID, N PHICH Seq, wherein mod() is a mod function, Cell_ID is a cell identity, F ( Cell_ID) is a function in which the cell identity is an independent variable, Operator _ ID is an operator identifier, F ( Cell _ ID, Operator _ ID) is a function in which the cell identity and the operator identifier are independent variables, N PHICH group is a quantity of PHICH groups, and N PHICH seq is a quantity of orthogonal sequences in each PHICH group; determining a number n _ u PHICH group of a PHICH group of the one or more PHICH resources according to a formula n _ u PHICH group = mod Cell _ ID, N PHICH group, n _ u PHICH group = mod F Cell _ ID, N PHICH group, or n _ u PHICH group = mod F Cell _ ID, Operator _ ID, N PHICH group; and determining a number n _ u PHICH seq of an orthogonal sequence in the PHICH group n _ u PHICH group of the one or more PHICH resources according to a formula n _ u PHICH seq = mod Cell _ ID, N PHICH seq, n _ u PHICH seq = mod F Cell _ ID, N PHICH seq, or n _ u PHICH seq = mod F Cell _ ID, Operator _ ID, N PHICH Seq, wherein mod() is a mod function, Cell_ID is a cell identity, F ( Cell_ID) is a function in which the cell identity is an independent variable, Operator _ ID is an operator identifier, F ( Cell _ ID, Operator _ ID) is a function in which the cell identity and the operator identifier are independent variables, N PHICH group is a quantity of PHICH groups, and N PHICH seq is a quantity of orthogonal sequences in each PHICH group; • sending the first subframe and the second subframe to a user equipment, wherein the second subframe is sent before the first subframe, the first subframe comprises M orthogonal frequency division multiplexing OFDM symbols, the second subframe comprises N OFDM symbols, M and N are positive integers, and M ≥ N (step 202).