Information indication method and apparatus
This disclosure discloses an information indication method and an apparatus, to resolve a problem that indication precision of an uplink precoding matrix is low. The method includes: receiving a downlink reference signal sent by a network device on a first transmission resource; performing channel estimation based on the downlink reference signal, to obtain a downlink equivalent channel corresponding to the first transmission resource; and determining, based on the downlink equivalent channel, to-be-indicated information corresponding to a terminal device, where the to-be-indicated information indicates an uplink precoding matrix used when a first terminal device sends uplink data on the first transmission resource. The downlink equivalent channel is obtained by performing channel estimation based on the downlink reference signal.
1 . An information obtaining method, comprising:
receiving, through M antennas, one or more downlink reference signals sent by a network device;
performing channel estimation based on a downlink reference signal of the one or more downlink reference signals, to obtain a downlink equivalent channel corresponding to a first transmission resource, wherein the downlink reference signal is received through a first antenna of the M antennas and carried on the first transmission resource, and the first antenna is for uplink sending; and
determining, based on the downlink equivalent channel, to-be-indicated information corresponding to a terminal device, the to-be-indicated information indicating an uplink precoding matrix used when the terminal device sends uplink data on the first transmission resource.
2 . The method according to claim 1 , wherein the downlink reference signal is obtained by the network device based on a downlink precoding matrix associated with the to-be-indicated information corresponding to the terminal device.
3 . The method according to claim 1 , wherein determining, based on the downlink equivalent channel, the to-be-indicated information corresponding to the terminal device comprises:
using the downlink equivalent channel on which normalization processing has been performed as the to-be-indicated information corresponding to the terminal device.
4 . The method according to claim 1 , the method further comprising:
receiving downlink control information (DCI) from the network device, wherein the DCI indicates N antenna ports on which the network device sends the downlink reference signal, and an uplink transmission rank, the DCI being associated with the N antenna ports, and N being an integer greater than 0; and
performing the channel estimation based on the downlink reference signal comprises:
performing channel estimation on the downlink reference signal that is from first n antenna ports of the N antenna ports and that is carried on the first transmission resource, wherein n is the uplink transmission rank.
5 . The method according to claim 4 , wherein the downlink reference signal sent on the N antenna ports is for determining the uplink precoding matrix.
6 . An apparatus, comprising:
a processor, and
one or more memories coupled to the processor and configured to store programming instructions that, when executed by the processor, cause the apparatus to perform operations comprising:
receiving, through M antennas, one or more downlink reference signals sent by a network device; and
performing channel estimation, based on a downlink reference signal of the one or more downlink reference signals, to obtain a downlink equivalent channel corresponding to a first transmission resource, wherein the downlink reference signal is received through a first antenna of the M antennas and carried on the first transmission resource, and the first antenna is for uplink sending;
determining, based on the downlink equivalent channel, to-be-indicated information corresponding to a terminal device, the to-be-indicated information indicating an uplink precoding matrix used when the terminal device sends uplink data on the first transmission resource.
7 . The apparatus according to claim 6 , wherein the downlink reference signal is obtained by the network device based on a downlink precoding matrix associated with the to-be-indicated information corresponding to the terminal device.
8 . The apparatus according to claim 6 , wherein when determining, based on the downlink equivalent channel, the to-be-indicated information corresponding to the terminal device, the operations comprise:
using the downlink equivalent channel on which normalization processing has been performed as the to-be-indicated information corresponding to the terminal device.
9 . The apparatus according to claim 6 , wherein the operations further comprise:
receiving downlink control information (DCI) from the network device, wherein the DCI indicates N antenna ports on which the network device sends the downlink reference signal, and an uplink transmission rank, the DCI being associated with the N antenna ports, and N being an integer greater than 0; and
when performing channel estimation based on the downlink reference signal, the operations comprise:
performing channel estimation on the downlink reference signal that is from first n antenna ports of the N antenna ports and that is carried on the first transmission resource, wherein n is the uplink transmission rank.
10 . The apparatus according to claim 9 , wherein the downlink reference signal sent on the N antenna ports is for determining the uplink precoding matrix.
11 . The apparatus according to claim 6 , wherein the apparatus is the terminal device; or
the apparatus is a chip or chip system.
12 . An apparatus, comprising:
a processor, and
one or more memories coupled to the processor and configured to store programming instructions that, when executed by the processor, cause the apparatus to perform operations comprising:
receiving uplink reference signals sent by a plurality of terminal devices comprising a first terminal device;
determining, based on the uplink reference signals sent by the plurality of terminal devices, to-be-indicated information corresponding to the first terminal device;
generating a downlink reference signal based on the to-be-indicated information, the to-be-indicated information indicating an uplink precoding matrix of a first terminal device; and
sending the downlink reference signal to the first terminal device on a first transmission resource.
13 . The apparatus according to claim 12 , wherein generating the downlink reference signal based on the to-be-indicated information comprises:
determining a downlink precoding matrix based on the to-be-indicated information corresponding to the first terminal device;
generating the downlink reference signal in accordance with the downlink precoding matrix.
14 . The apparatus according to claim 13 , wherein if a network device uses a same antenna port to send downlink reference signals to K terminal devices on the first transmission resource, and the K terminal devices comprise the first terminal device, the operations comprise:
obtaining downlink channel responses of the K terminal devices and to-be-indicated information corresponding to the respective K terminal devices;
determining the downlink precoding matrix based on a first matrix and a second matrix, wherein the first matrix comprises the downlink channel responses of the K terminal devices, and the second matrix comprises the to-be-indicated information corresponding to the respective K terminal devices.
15 . The apparatus according to claim 12 , wherein the operations further comprise:
sending downlink control information (DCI) to the first terminal device, wherein the DCI indicates N antenna ports on which the network device sends the downlink reference signal, and an uplink transmission rank, the DCI being associated with the N antenna ports, and N being an integer greater than 0; and
when sending the downlink reference signal to the first terminal device on the first transmission resource, the operations comprise:
sending the downlink reference signal to the first terminal device on the first transmission resource through the N antenna ports.
16 . The apparatus according to claim 12 , wherein a frequency-domain granularity of the to-be-indicated information corresponding to the first terminal device is related to a resource size of the first transmission resource.
17 . The apparatus according to claim 12 , wherein the apparatus is the network device; or
the apparatus is a chip or chip system.