1. A method for transmitting a dedicated pilot, comprising the steps of: configuring a dedicated pilot with an orthogonal sequence over a resource for transmission of the dedicated pilot according to a preset mapping rule; and transmitting the dedicated pilot in a Code Division Multiplexing, CDM, mode or in a hybrid CDM and Frequency Division Multiplexing, FDM, mode, wherein adjacent sub-carriers, corresponding to the same port, for transmission of the dedicated pilot have their orthogonal sequences selected from different sets of orthogonal sequences; for a system at a transmission rank of 1 to 4, two adjacent sub-carriers, corresponding to the same port, for transmission of the dedicated pilot have their orthogonal sequences selected from different sets of orthogonal sequences; for a system at a transmission rank of 5 to 8, two adjacent sub-carriers, corresponding to the same port, for transmission of the dedicated pilot have their orthogonal sequences selected from different sets of orthogonal sequences; wherein for a system at the transmission rank of 1 to 4, two adjacent sub-carriers, corresponding to the same port, for transmission of the dedicated pilot have their orthogonal sequences selected from different sets of orthogonal sequences in a frequency order within a system bandwidth; for a system at the transmission rank of 5 to 8, two adjacent sub-carriers, corresponding to the same port, for transmission of the dedicated pilot have their orthogonal sequences selected from different sets of orthogonal sequences in a frequency order within a system bandwidth.