Solution to beam squint for wideband communications
Embodiments of the present disclosure relate to hybrid beamforming. A plurality of time delay elements is used to perform analog beamforming. Each time delay element is configured to apply the same time delay at different frequencies. The plurality of time delay elements is coupled to at least one RF chain to receive signals. Each antenna in an antenna array is configured to be selectively connected to one of the plurality of time delay elements based on a target configuration of a connection between the plurality of time delay elements and the antenna array. In operation, the target configuration is determined based on time delay information concerning the plurality of time delay elements and channel information concerning a physical channel over which the signals are to be transmitted.
1. An apparatus comprising:
at least one processor; and
at least one memory including computer program codes;
the at least one memory and the computer program codes are configured to, with the at least one processor, cause the apparatus to:
obtain time delay information concerning a plurality of time delay elements, a time delay element of the plurality of time delay elements configured to apply a same time delay at a plurality of frequencies;
determine target precoding information for the plurality of frequencies based on channel information concerning a physical channel, signals at the plurality of frequencies are to be transmitted over the physical channel;
determine a target configuration of a connection between the plurality of time delay elements and an antenna array based on the time delay information and the target precoding information, the target configuration indicating a time delay element to which an antenna in the antenna array is to be connected.
2. The apparatus of claim 1 , wherein the apparatus caused to determine the target configuration comprises the apparatus caused to:
determine a digital precoding matrix for the plurality of frequencies based on the target precoding information, the time delay information and a first configuration of the connection;
determine a second configuration of the connection based on the digital precoding matrix, the target precoding information, and the time delay information;
update the digital precoding matrix based on the second configuration, the target precoding information and the time delay information; and
in accordance with a determination that a difference between the updated digital precoding matrix and the digital precoding matrix is below a threshold, determine the second configuration as the target configuration.
3. The apparatus of claim 2 , wherein the apparatus caused to determine the second configuration comprises the apparatus caused to:
determine, for a given antenna in the antenna array, a target function based on the time delay information, the digital precoding matrix, and a portion of the target precoding information corresponding to the given antenna; and
determine, from the plurality of time delay elements, a target time delay element for the given antenna by minimizing the target function.
4. The apparatus of claim 2 , wherein the apparatus is further caused to:
generate the first configuration of the connection by randomly selecting a time delay element from the plurality of time delay elements for each antenna in the antenna array.
5. The apparatus of claim 1 , wherein the apparatus is further caused to:
cause a switching circuit to connect the antenna in the antenna array to the indicated time delay element.
6. A device comprising:
a plurality of time delay elements coupled to at least one radio frequency chain, a time delay element of the plurality of time delay elements being configured to apply a same time delay to signals at a plurality of frequencies received from the at least one radio frequency chain; and
an antenna array, an antenna in the antenna array being configured to be selectively connected to a time delay element of the plurality of time delay elements based on a target configuration of a connection between the plurality of time delay elements and the antenna array.
7. The device of claim 6 , wherein the plurality of time delay elements comprises a plurality groups of time delay elements and each group of the plurality group of time delay elements is coupled one of the at least one radio frequency chain.
8. The device of claim 7 , wherein each group of the plurality groups of time delay elements has the same number of time delay elements.
9. The device of claim 7 , wherein time delays applied by time delay elements in the same group of time delay elements are different from each other.
10. The device of claim 6 , further comprising:
a switching circuit coupled between the plurality of time delay elements and the antenna array and configured to connect the antenna in the antenna array to the time delay element based on the target configuration.
11. The device of claim 6 , wherein the time delay applied by the time delay element of the plurality of time delay elements is fixed during operation of the device.
12. The device of claim 6 , wherein the device comprises a network device.
13. A method comprising:
obtaining time delay information concerning a plurality of time delay elements, a time delay element of the plurality of time delay elements configured to apply a same time delay at a plurality of frequencies;
determining target precoding information for the plurality of frequencies based on channel information concerning a physical channel, signals at the plurality of frequencies are to be transmitted over the physical channel;
determining a target configuration of a connection between the plurality of time delay elements and an antenna array based on the time delay information and the target precoding information, the target configuration indicating a time delay element to which an antenna in the antenna array is to be connected.
14. The method of claim 13 , wherein determining the target configuration comprises:
determining a digital precoding matrix for the plurality of frequencies based on the target precoding information, the time delay information and a first configuration of the connection;
determining a second configuration of the connection based on the digital precoding matrix, the target precoding information, and the time delay information;
updating the digital precoding matrix based on the second configuration, the target precoding information and the time delay information; and
in accordance with a determination that a difference between the updated digital precoding matrix and the digital precoding matrix is below a threshold, determining the second configuration as the target configuration.
15. The method of claim 14 , wherein determining the second configuration comprises:
determining, for a given antenna in the antenna array, a target function based on the time delay information, the digital precoding matrix, and a portion of the target precoding information corresponding to the given antenna; and
determining, from the plurality of time delay elements, a target time delay element for the given antenna by minimizing the target function.
16. The method of claim 14 , further comprising:
generating the first configuration of the connection by randomly selecting a time delay element from the plurality of time delay elements for each antenna in the antenna array.
17. The method of claim 13 , further comprising:
causing a switching circuit to connect the antenna in the antenna array to the indicated time delay element.