Communication method, apparatus, and system

Abstract

This application relates to the field of wireless communications, and in particular, to a communication method, an apparatus, and a system in a wireless communications system. In the method, a terminal device detects a physical downlink control channel PDCCH sent by a network device, the PDCCH carries indication information, and the indication information is used to indicate a type of system information; the terminal device determines, based on the indication information, a physical resource carrying the system information; and the terminal device receives the system information on the physical resource. Based on this method, a network device can flexibly indicate a type of system information that needs to be sent.

What is claimed is: 
     
         1 . A method, comprising:
 sending, by a network device, a physical downlink control channel (PDCCH) carrying downlink control information (DCI), wherein the DCI comprises indication information, and the indication information indicates that a type of system information is either system information block type1 (SIB1) or a system information (SI) message, wherein the SI message carries system information blocks (SIBs) other than SIB1; and   sending, by the network device, the system information and a demodulation reference signal (DMRS) of the system information, wherein the frequency domain reference point of the DMRS is one of at least two frequency domain reference points that are used to determine DMRSs for the SIB1 and the SI message, and the frequency domain reference point used to determine the DMRS of the SIB1 and the frequency domain reference point used to determine the DMRS of the SI message are different.   
     
     
         2 . The method according to  claim 1 , wherein
 a cyclic redundancy code (CRC) comprised in the DCI is scrambled by a system information-radio network temporary identifier (SI-RNTI).   
     
     
         3 . The method according to  claim 1 , wherein
 the indication information is one bit carried in the DCI.   
     
     
         4 . The method according to  claim 3 , wherein
 when the one bit is a first value, the downlink control information indicates that the type of the system information is SIB1; or   when the one bit is a second value, the downlink control information indicates the type of the system information is SI message.   
     
     
         5 . The method according to  claim 1 , wherein
 at least one of a time domain resource and frequency domain resource of the PDCCH is indicated by information carried in a synchronization/broadcast channel block.   
     
     
         6 . A method, comprising:
 obtaining, by a terminal device, downlink control information (DCI) by detecting a physical downlink control channel (PDCCH) carrying the DCI, wherein the downlink control information comprises indication information, and the indication information indicates that a type of system information is either system information block type1 (SIB1) or a system information (SI) message, wherein the SI message carries system information blocks (SIBs) other than SIB1;   determining, by the terminal device according to the DCI, a physical resource carrying the system information;   obtaining, by the terminal device according to a frequency domain reference point, a demodulation reference signal (DMRS) for the physical resource, wherein the frequency domain reference point is one of at least two frequency domain reference points that are used to determine DMRSs for the SIB1 and the SI message, and the frequency domain reference points that are used to obtain DMRSs are different for the SIB1 and the SI message; and   obtaining, by the terminal device based on the DMRS, the system information on the physical resource.   
     
     
         7 . The method according to  claim 6 , wherein
 a cyclic redundancy code (CRC) comprised in the DCI is scrambled by a system information-radio network temporary identifier (SI-RNTI).   
     
     
         8 . The method according to  claim 6 , wherein
 the indication information is one bit carried in the DCI.   
     
     
         9 . The method according to  claim 8 , wherein
 when the one bit is a first value, the downlink control information indicates that the type of the system information is SIB1; or   when the one bit is a second value, the downlink control information indicates the type of the system information is SI message.   
     
     
         10 . The method according to  claim 6 , wherein
 at least one of a time domain resource and frequency domain resource of the PDCCH is indicated by information carried in a synchronization/broadcast channel block.   
     
     
         11 . An apparatus, comprising at least one processor and a memory, where the memory stores a computer program for execution by the at least one processor, wherein the computer program, when executed, cause the apparatus to perform operations comprising:
 sending a physical downlink control channel (PDCCH) carrying downlink control information (DCI), wherein the DCI comprises indication information, and the indication information indicates that a type of system information is either system information block type1 (SIB1) or a system information (SI) message, wherein the SI message carries system information blocks (SIBs) other than SIB1; and   sending the system information and a demodulation reference signal (DMRS) of the system information, wherein the frequency domain reference point of the DMRS is one of at least two frequency domain reference points that are used to determine DMRSs for the SIB1 and the SI message, and the frequency domain reference point used to determine the DMRS of the SIB1 and the frequency domain reference point used to determine the DMRS of the SI message are different.   
     
     
         12 . The apparatus according to  claim 11 , wherein
 a cyclic redundancy code (CRC) comprised in the DCI is scrambled by a system information-radio network temporary identifier (SI-RNTI).   
     
     
         13 . The apparatus according to  claim 11 , wherein
 the indication information is one bit carried in the DCI.   
     
     
         14 . The apparatus according to  claim 13 , wherein
 when the one bit is a first value, the downlink control information indicates that the type of the system information is SIB1; or   when the one bit is a second value, the downlink control information indicates the type of the system information is SI message.   
     
     
         15 . The apparatus according to  claim 11 , wherein at least one of a time domain resource and frequency domain resource of the PDCCH is indicated by information carried in a synchronization/broadcast channel block. 
     
     
         16 . An apparatus, comprising at least one processor and a memory, where the memory stores a computer program for execution by the at least one processor, wherein the computer program, when executed, cause the apparatus to perform operations comprising:
 obtaining downlink control information (DCI) by detecting a physical downlink control channel (PDCCH) carrying the DCI, wherein the downlink control information comprises indication information, and the indication information indicates that a type of system information is either system information block type1 (SIB1) or a system information (SI) message, wherein the SI message carries system information blocks (SIBs) other than SIB1;   determining, according to the DCI, a physical resource carrying the system information;   obtaining, according to a frequency domain reference point, a demodulation reference signal (DMRS) for the physical resource, wherein the frequency domain reference point is one of at least two frequency domain reference points that are used to determine DMRSs for the SIB1 and the SI message, and the frequency domain reference points that are used to obtain DMRSs are different for the SIB1 and the SI message; and   obtaining, based on the DMRS, the system information on the physical resource.   
     
     
         17 . The apparatus according to  claim 16 , wherein
 a cyclic redundancy code (CRC) comprised in the DCI is scrambled by a system information-radio network temporary identifier (SI-RNTI).   
     
     
         18 . The apparatus according to  claim 16 , wherein
 the indication information is one bit carried in the DCI.   
     
     
         19 . The apparatus according to  claim 18 , wherein
 when the one bit is a first value, the downlink control information indicates that the type of the system information is SIB1; or   when the one bit is a second value, the downlink control information indicates the type of the system information is SI message.   
     
     
         20 . The apparatus according to  claim 16 , wherein at least one of a time domain resource and frequency domain resource of the PDCCH is indicated by information carried in a synchronization/broadcast channel block.