Method for sending downlink control information, terminal device, and network device
Embodiments of this application provide a method for sending downlink control information, a terminal device, and a network device, and relate to the communications field, to resolve problems of low flexibility and low reliability of a system DCI configuration. The method includes: receiving DCI for scheduling downlink data to be transmitted as one codeword, wherein the DCI comprises a value of a set of values each indicating a corresponding quantity of layers of the one codeword and one or more antenna ports used for sending the one codeword, and wherein the set of values comprises: a first value indicating that the quantity of layers of the one codeword is 2, and a first antenna port and a second antenna port are used for sending the one codeword, and a second value indicating that the quantity of layers of the one codeword is 2 and a third antenna port and a fourth antenna port are used for sending the one codeword.
1. A method for receiving downlink control information (DCI), the method comprising:
receiving, by an apparatus, DCI for scheduling downlink data to be transmitted as one codeword on a downlink channel, wherein the DCI is represented by 6 bits and comprises a value selected from a set of values, wherein the set of values comprises:
a first value indicating that a precoding scheme for the downlink channel adopts a four-layer transmit diversity;
a second value to a seventeenth value, each indicating that the precoding scheme adopts a one-layer transmission and uses precoding matrices determined based on transmit precoding matrix indications (TPMIs) with values between 0 and 15;
an eighteenth value indicating that the precoding scheme adopts a one-layer transmission, and precoding reported by a latest precoding matrix indication (PMI) carried on a physical uplink shared channel (PUSCH) is used as a precoding matrix;
a nineteenth value to a thirty-fourth value indicating that the precoding scheme adopts a two-layer transmission and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a thirty-fifth value indicating that a precoding scheme adopts two-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix;
a thirty-sixth value to a fifty-first value indicating that a precoding scheme adopts a three-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a fifty-second value indicating that the precoding scheme adopts a three-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix; and
a fifty-third value to a sixtieth value indicating that the precoding scheme adopts a four-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15; and
determining, by the apparatus, the precoding matrix for the downlink data based on the DCI.
2. The method according to claim 1 , wherein the set of values further comprises:
a value indicating that a precoding scheme adopts a four-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix.
3. The method according to 1, further comprising:
receiving, by the apparatus, the downlink data.
4. A communications apparatus, comprising a memory and one or more processors, wherein the memory stores programming instructions for execution by the one or more processors, the programming instructions instruct the communications apparatus to perform operations comprising:
receiving, by an apparatus, DCI for scheduling downlink data to be transmitted as one codeword on a downlink channel, wherein the DCI is represented by 6 bits and comprises a value selected from a set of values, wherein the set of values comprises:
a first value indicating that a precoding scheme for the downlink channel adopts a four-layer transmit diversity;
a second value to a seventeenth value, each indicating that the precoding scheme adopts a one-layer transmission and uses precoding matrices determined based on transmit precoding matrix indications (TPMIs) with values between 0 and 15;
an eighteenth value indicating that the precoding scheme adopts a one-layer transmission, and precoding reported by a latest precoding matrix indication (PMI) carried on a physical uplink shared channel (PUSCH) is used as a precoding matrix;
a nineteenth value to a thirty-fourth value indicating that the precoding scheme adopts a two-layer transmission and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a thirty-fifth value indicating that a precoding scheme adopts two-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix;
a thirty-sixth value to a fifty-first value indicating that a precoding scheme adopts a three-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a fifty-second value indicating that the precoding scheme adopts a three-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix; and
a fifty-third value to a sixtieth value indicating that the precoding scheme adopts a four-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15; and
determining, by the apparatus, the precoding matrix for the downlink data based on the DCI.
5. The apparatus according to claim 4 , wherein the set of values further comprises:
a value indicating that a precoding scheme adopts a four-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix.
6. The communications apparatus according to 4, wherein the operations further comprising:
receiving the downlink data.
7. A method for sending downlink control information, comprising:
generating downlink control information (DCI) for scheduling downlink data to be transmitted on a downlink channel using one codeword, wherein the DCI is represented by 6 bits and comprises a value selected from a set of values, wherein the set of values comprises:
a first value indicating that a precoding scheme for the downlink channel adopts a four-layer transmit diversity;
a second value to a seventeenth value, each indicating that the precoding scheme adopts a one-layer transmission and uses precoding matrices determined based on transmit precoding matrix indications (TPMIs) with values between 0 and 15;
an eighteenth value indicating that the precoding scheme adopts a one-layer transmission, and precoding reported by a latest precoding matrix indication (PMI) carried on a physical uplink shared channel (PUSCH) is used as a precoding matrix;
a nineteenth value to a thirty-fourth value indicating that the precoding scheme adopts a two-layer transmission and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a thirty-fifth value indicating that a precoding scheme adopts two-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix;
a thirty-sixth value to a fifty-first value indicating that a precoding scheme adopts a three-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a fifty-second value indicating that the precoding scheme adopts a three-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix; and
a fifty-third value to a sixtieth value indicating that the precoding scheme adopts a four-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
determining, by the apparatus, the precoding matrix for the downlink data based on the DCI; and
sending the DCI to a communications apparatus.
8. The method according to claim 7 , wherein the set of values further comprises:
a value indicating that a precoding scheme adopts a four-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix.
9. The method according to 7, further comprising:
sending the downlink data to the communications apparatus.
10. A communications apparatus, comprising a memory and one or more processors, wherein the memory stores programming instructions for execution by the one or more processors, the programming instructions instruct the communications apparatus to perform operations comprising:
generating downlink control information (DCI) for scheduling downlink data to be transmitted on a downlink channel using one codeword, wherein the DCI is represented by 6 bits and comprises a value selected from a set of values, wherein the set of values comprises:
a first value indicating that a precoding scheme for the downlink channel adopts a four-layer transmit diversity;
a second value to a seventeenth value, each indicating that the precoding scheme adopts a one-layer transmission and uses precoding matrices determined based on transmit precoding matrix indications (TPMIs) with values between 0 and 15;
an eighteenth value indicating that the precoding scheme adopts a one-layer transmission, and precoding reported by a latest precoding matrix indication (PMI) carried on a physical uplink shared channel (PUSCH) is used as a precoding matrix;
a nineteenth value to a thirty-fourth value indicating that the precoding scheme adopts a two-layer transmission and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a thirty-fifth value indicating that a precoding scheme adopts two-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix;
a thirty-sixth value to a fifty-first value indicating that a precoding scheme adopts a three-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
a fifty-second value indicating that the precoding scheme adopts a three-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix; and
a fifty-third value to a sixtieth value indicating that the precoding scheme adopts a four-layer transmission, and uses precoding matrices determined based on TPMIs with values between 0 and 15;
determining the precoding matrix for the downlink data based on the DCI; and
sending the DCI to another communications apparatus.
11. The communications apparatus according to claim 10 , wherein the set of values further comprises:
a value indicating that a precoding scheme adopts a four-layer transmission, and precoding reported by the latest PMI carried on the PUSCH is used as the precoding matrix.
12. The communications apparatus according to claim 10 , wherein the operations further comprising:
sending the downlink data to the another communications apparatus.