Method and system for mobile terminal to securely receive signal according to spread spectrum and despread spectrum, and storage medium and mobile terminal

A base station, comprising:

• a memory configured to store instructions;
• a processor configured to execute the instructions, which cause the processor to perform steps comprising:
• pre-configuring a first standard PN sequence and a second standard PN sequence, and when communication between the base station and a mobile station is established, allocating and transmitting a first start bit serial number of the first standard PN sequence and a second start bit serial number of the second standard PN sequence to the mobile terminal;
• based on the first start bit serial number of the first standard PN sequence, obtaining a first cyclic PN sequence, and based on the second start bit serial number of the second standard PN sequence, obtaining a second cyclic PN sequence;
• when transmitting information to the mobile terminal, randomly XORing corresponding digits of a low frequency digital sequence of information to be transmitted and the first cyclic PN sequence and the second cyclic PN sequence, to obtain a spread sequence, and transmitting the spread sequence out;
• and
• when receiving information from the mobile terminal,
• receiving a spread sequence transmitted by the mobile terminal, and XORing the spread sequence transmitted by the base station with the first cyclic PN sequence and the second cyclic PN sequence, to obtain a first sequence to be determined and a second sequence to be determined;
• and
• for each of the first sequence to be determined and the second sequence to be determined, determining whether the first sequence to be determined or the second sequence to be determined is a high frequency digital sequence, and if so, discarding the first sequence to be determined or the second sequence to be determined, and if not, determining that the first sequence to be determined or the second sequence to be determined is the information from the mobile terminal.

A non-transitory computer-readable medium with instructions stored thereon, that when executed by a processor in a mobile terminal, cause the processor to perform steps comprising:

• pre-configuring a first standard PN sequence and a second standard PN sequence, and when communication between the mobile terminal and a base station is established, receiving a first start bit serial number of the first standard PN sequence and a second start bit serial number of the second standard PN sequence from the base station;
• based on the first start bit serial number of the first standard PN sequence, obtaining a first cyclic PN sequence, and based on the second start bit serial number of the second standard PN sequence, obtaining a second cyclic PN sequence;
• when transmitting information to the base station, randomly XORing corresponding digits of a low frequency digital sequence of information to be transmitted and the first cyclic PN sequence and the second cyclic PN sequence, to obtain a spread sequence, and transmitting the spread sequence out;
• and
• when receiving information from the base station,
• receiving a spread sequence transmitted by the base station, and XORing the spread sequence transmitted by the base station with the first cyclic PN sequence and the second cyclic PN sequence, to obtain a first sequence to be determined and a second sequence to be determined;
• and
• for each of the first sequence to be determined and the second sequence to be determined, determining whether the first sequence to be determined or the second sequence to be determined is a high frequency digital sequence, and if so, discarding the first sequence to be determined or the second sequence to be determined, and if not, determining that the first sequence to be determined or the second sequence to be determined is the information from the base station.