A bus system comprising: a bus controller, bus terminals, and a two-wire bus, wherein the bus controller and each of the bus terminals are connected via the two-wire bus to constitute a network, the bus controller communicates with any of the bus terminals using Orthogonal Frequency Division Multiplexing, OFDM, technology, the bus terminals communicate with each other using OFDM technology, subcarriers occupied by each of the bus terminals do not interfere with each other, and a frame structure of a signal frame used during communication comprises a downlink system subframe, a downlink subframe, and an uplink subframe; the bus controller is configured to: transmit a downlink pilot signal in the downlink system subframe; transmit a broadcast message in the downlink subframe to instruct a bus terminal to be initialized; after reception of an access request transmitted by the bus terminal in the uplink subframe, allocate channel resource blocks for the bus terminal based upon service information in the access request; determine a transmission delay between the bus terminal and the bus controller based upon a difference between a reception time and a sending time of the access request; and transmit a result of allocating the channel resource blocks and the transmission delay between the bus terminal and the bus controller to the bus terminal in the downlink subframe; and the bus terminal is configured to: perform system synchronization and channel estimation, based upon the received downlink pilot signal; transmit the access request in the uplink subframe after reception of the broadcast message; transmit and receive service data based upon the received result of allocating the channel resource blocks; adjust a transmission delay of sending time for a signal to be transmitted to the bus controller according to the transmission delay between the bus terminal and the bus controller, so as to be synchronized with the system. a bus controller, bus terminals, and a two-wire bus, wherein the bus controller and each of the bus terminals are connected via the two-wire bus to constitute a network, the bus controller communicates with any of the bus terminals using Orthogonal Frequency Division Multiplexing, OFDM, technology, the bus terminals communicate with each other using OFDM technology, subcarriers occupied by each of the bus terminals do not interfere with each other, and a frame structure of a signal frame used during communication comprises a downlink system subframe, a downlink subframe, and an uplink subframe; the bus controller is configured to: transmit a downlink pilot signal in the downlink system subframe; transmit a broadcast message in the downlink subframe to instruct a bus terminal to be initialized; after reception of an access request transmitted by the bus terminal in the uplink subframe, allocate channel resource blocks for the bus terminal based upon service information in the access request; determine a transmission delay between the bus terminal and the bus controller based upon a difference between a reception time and a sending time of the access request; and transmit a result of allocating the channel resource blocks and the transmission delay between the bus terminal and the bus controller to the bus terminal in the downlink subframe; and the bus terminal is configured to: perform system synchronization and channel estimation, based upon the received downlink pilot signal; transmit the access request in the uplink subframe after reception of the broadcast message; transmit and receive service data based upon the received result of allocating the channel resource blocks; adjust a transmission delay of sending time for a signal to be transmitted to the bus controller according to the transmission delay between the bus terminal and the bus controller, so as to be synchronized with the system.