Signal transmission based on downlink control information

1. A method for transmitting signal, wherein the method comprising:

receiving, by a terminal device, downlink control information (DCI) from a network device, wherein the DCI includes a signaled precoding matrix index, wherein the signaled precoding matrix index is an index renumbered from a corresponding index in a first index set, and the signaled precoding matrix index is different from the corresponding index, at least one index in the first index set is greater than a quantity of the first index set, the signaled precoding matrix index is less than the quantity of the first index set, the signaled precoding matrix index is used to determine a precoding matrix for transmitting data by the terminal device, each index in the first index set corresponds to a precoding matrix in a first precoding matrix set, a second precoding matrix set comprises a plurality of precoding matrix sets including the first precoding matrix set, and the first precoding matrix set is a proper subset of the second precoding matrix set; and

transmitting, by the terminal device, the data according to the signaled precoding matrix index.

2. The method according to claim 1 , wherein before the receiving, by a terminal device, DCI from a network device, the method further comprises:

receiving, by the terminal device, information of the first precoding matrix set from the network device, wherein the information of the first precoding matrix set indicates the first precoding matrix set.

3. The method according to claim 2 , wherein information of the first precoding matrix set is included in a higher layer signaling message from the network device.

4. The method according to claim 1 , wherein the first precoding matrix set is determined according to coherent information of transmit antenna ports of the terminal device.

5. An apparatus for transmitting signal, comprising:

a receiver, configured to receive downlink control information (DCI) from a network device, wherein the DCI includes a signaled precoding matrix index, wherein the signaled precoding matrix index is an index renumbered from a corresponding index in a first index set, and the signaled precoding matrix index is different from the corresponding index, at least one index in the first index set is greater than a quantity of the first index set, the signaled precoding matrix index is less than the quantity of the first index set, the signaled precoding matrix index is used to determine a precoding matrix for transmitting data by the apparatus, each index in the first index set corresponds to a precoding matrix in a first precoding matrix set, a second precoding matrix set comprises a plurality of precoding matrix sets including the first precoding matrix set and the first precoding matrix set is a proper subset of the second precoding matrix set; and

a transmitter, configured to transmit the data according to the signaled precoding matrix index.

6. The apparatus according to claim 5 , wherein:

the receiver is configured to receive information of the first precoding matrix set from the network device, wherein the information of the first precoding matrix set indicates the first precoding matrix set.

7. The apparatus according to claim 6 , wherein information of the first precoding matrix set is included in a higher layer signaling message from the network device.

8. The apparatus according to claim 5 , wherein the first precoding matrix set is determined according to coherent information of transmit antenna ports of the apparatus.

9. A method for receiving signal, wherein the method comprising:

determining, by a network device, a signaled precoding matrix index, wherein the signaled precoding matrix index is an index renumbered from a corresponding index in a first index set, and the signaled precoding matrix index is different from the corresponding index, at least one index in the first index set is greater than a quantity of the first index set, the signaled precoding matrix index is less than the quantity of the first index set, the signaled precoding matrix index is used to determine a precoding matrix for transmitting data by a terminal device, each index in the first index set corresponds to a precoding matrix in a first precoding matrix set, a second precoding matrix set comprises a plurality of precoding matrix sets including the first precoding matrix set, the first precoding matrix set is a proper subset of the second precoding matrix set;

transmitting, by the network device, downlink control information (DCI) to the terminal device, wherein the DCI includes the signaled precoding matrix index; and

receiving, by the network device, the data transmitted by the terminal device according to the signaled precoding matrix index.

10. The method according to claim 9 , wherein before the determining, by a network device, a precoding matrix index in a first index set, the method further comprises:

configuring, by the network device, information of the first precoding matrix set, wherein the information of the first precoding matrix set indicates the first precoding matrix set; and

transmitting, by the network device, the information of the first precoding matrix set to the terminal device.

11. The method according to claim 10 , wherein information of the first precoding matrix set is included in a higher layer signaling message sent by the network device.

12. The method according to claim 9 , wherein the first precoding matrix set is determined according to coherent information of transmit antenna ports of the terminal device.