Double-stream beamforming method and device
Disclosed are a double-stream beamforming method and device, which relate to communication technology. The method comprises: first, according to a DOA angle, determining an array response vector; then according to the array response vector, in accordance with the number of each group of transmission antennae of a base station, distributing parameters to generate two groups of coefficients, and according to the two groups of coefficients, conducting beamforming on the antennae. There is no need to conduct characteristic value decomposition to obtain a characteristic vector, thereby reducing the double-stream beamforming complexity.
1. A method of dual-stream beamforming, comprising:
determining Direction Of Arrival (DOA) angles of antennas;
determining array response vectors from the DOA angles;
generating two sets of coefficients from the array response vectors by allocating parameters according to the numbers of respective sets of transmit antennas of a base station; and
performing beamforming respectively for two sets of antennas by the two sets of coefficients;
wherein the determining the DOA angles of the antennas comprises:
performing uplink channel estimation using an uplink pilot of a full bandwidth or a preset sub-band to determine a channel matrix;
determining a channel related matrix from the channel matrix; and
determining the DOA angles of the antennas from the channel related matrix.
2. The method of claim 1 , wherein the determining the array response vectors from the DOA angles comprises:
determining the array response vectors as V=e j2π[0:N t −1]d sin θ DOA , wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
3. The method of claim 2 , wherein the generating the two sets of coefficients from the array response vectors by allocating the parameters according to the numbers of respective sets of transmit antennas of the base station comprises:
determining the dimensionality of the two sets of coefficients to be the same as the dimensionality of the array response vectors;
determining parameters of a first half of the first set of coefficients to be the same as parameters of a first half of the conjugated array response vectors and determining parameters of a second half of the first set of coefficients to be zero; and
determining parameters of a second half of the second set of coefficients to be the same as the parameters of the first half of the conjugated array response vectors and determining parameters of a first half of the second set of coefficients to be zero.
4. The method of claim 1 , wherein the determining the array response vectors from the DOA angles comprises:
determining the array response vectors as V=e −j2π[0:N t −1]d sin θ DOA , wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
5. The method of claim 4 , wherein the generating the two sets of coefficients from the array response vectors by allocating the parameters according to the numbers of respective sets of transmit antennas of the base station comprises:
determining the dimensionality of the two sets of coefficients to be the same as the dimensionality of the array response vectors;
determining parameters of a first half of the first set of coefficients to be the same as parameters of a first half of the array response vectors and determining parameters of a second half of the first set of coefficients to be zero; and
determining parameters of a second half of the second set of coefficients to be the same as the parameters of the first half of the array response vectors and determining parameters of a first half of the second set of coefficients to be zero.
6. The method of claim 1 , wherein the determining the array response vectors from the DOA angles comprises:
determining the array response vectors as V=e −j2π[0:N t /2−1]d sin θ DOA , wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
7. The method of claim 6 , wherein the generating the two sets of coefficients from the array response vectors by allocating the parameters according to the numbers of respective sets of transmit antennas of the base station comprises:
determining the dimensionality of the two sets of coefficients to be twice the dimensionality of the array response vectors;
determining parameters of a first half of the first set of coefficients to be the same as parameters of the array response vectors and determining parameters of a second half of the first set of coefficients to be zero; and
determining parameters of a second half of the second set of coefficients to be the same as the parameters of the array response vectors and determining parameters of a first half of the second set of coefficients to be zero.
8. The method of claim 1 , wherein the performing beamforming respectively for two sets of antennas by the two sets of coefficients comprises:
normalizing in amplitude the two sets of coefficients;
determining weight coefficients of the antennas as the product of the normalized coefficients and √{square root over (P)}, wherein P represents limited power of the antennas; and
performing beamforming for the two sets of antennas by the weight coefficients of the antennas.
9. The method of claim 1 , wherein the performing beamforming respectively for two sets of antennas by the two sets of coefficients comprises:
selecting codebooks at a preset beamforming granularity to multiply respectively with the two sets of coefficients to derive two sets of intermediate weight coefficients;
determining the highest power M of the respective antennas from the two sets of intermediate weight coefficients;
determining weight coefficients of the antennas as the products of the two respective sets of intermediate weight coefficients and √{square root over (P/M)}, where P represents limited power of the antennas; and
performing beamforming for the two sets of antennas by the weight coefficients of the antennas.
10. An apparatus for dual-stream beamforming, comprising:
an angle determination unit is configured to determine Direction Of Arrival (DOA) angles of antennas;
a vector determination unit is configured to determine array response vectors from the DOA angles;
a coefficient determination unit is configured to generate two sets of coefficients from the array response vectors by allocating parameters according to the numbers of respective sets of transmit antennas of a base station; and
a beamforming unit is configured to perform beamforming respectively for two sets of antennas by the two sets of coefficients;
wherein the angle determination unit is further configured:
to perform uplink channel estimation using an uplink pilot of a full bandwidth or a preset sub-band to determine a channel matrix;
to determine a channel related matrix from the channel matrix; and
to determine the DOA angles of the antennas from the channel related matrix.
11. The apparatus of claim 10 , wherein the vector determination unit is further configured:
to determine the array response vectors as V=e j2π[0:N t −1]d sin θ DOA ,wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
12. The apparatus of claim 11 , wherein the coefficient determination unit is further configured:
to determine the dimensionality of the two sets of coefficients to be the same as the dimensionality of the array response vectors;
to determine parameters of a first half of the first set of coefficients to be the same as parameters of a first half of the conjugated array response vectors and to determine parameters of a second half of the first set of coefficients to be zero; and
to determine parameters of a second half of the second set of coefficients to be the same as the parameters of the first half of the conjugated array response vectors and to determine parameters of a first half of the second set of coefficients to be zero.
13. The apparatus of claim 10 , wherein the vector determination unit is further configured:
to determine the array response vectors as V=e −j2π[0:N t −1]d sin θ DOA , wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
14. The apparatus of claim 13 , wherein the coefficient determination unit is further configured:
to determine the dimensionality of the two sets of coefficients to be the same as the dimensionality of the array response vectors;
to determine parameters of a first half of the first set of coefficients to be the same as parameters of a first half of the array response vectors and to determine parameters of a second half of the first set of coefficients to be zero; and
to determine parameters of a second half of the second set of coefficients to be the same as the parameters of the first half of the array response vectors and to determine parameters of a first half of the second set of coefficients to be zero.
15. The apparatus of claim 10 , wherein the vector determination unit is further configured:
to determine the array response vectors as V=e −j2π[0:N t /2−1]d sin θ DOA , wherein N t represents the number of transmit antennas of the base station, and d represents the spacing between the antennas of the base station.
16. The apparatus of claim 15 , wherein the coefficient determination unit is further configured:
to determine the dimensionality of the two sets of coefficients to be twice the dimensionality of the array response vectors;
to determine parameters of a first half of the first set of coefficients to be the same as parameters of the array response vectors and to determine parameters of a second half of the first set of coefficients to be zero; and
to determine parameters of a second half of the second set of coefficients to be the same as the parameters of the array response vectors and to determine parameters of a first half of the second set of coefficients to be zero.
17. The apparatus of claim 10 , wherein the beamforming unit is further configured:
to normalize in amplitude the two sets of coefficients;
to determine weight coefficients of the antennas as the product of the normalized coefficients and √{square root over (P)}, wherein P represents limited power of the antennas; and
to perform beamforming for the two sets of antennas by the weight coefficients of the antennas.
18. The apparatus of claim 10 , wherein the beamforming unit is further configured:
to select codebooks at a preset beamforming granularity to multiply respectively with the two sets of coefficients to derive two sets of intermediate weight coefficients;
to determine the highest power M of the respective antennas from the two sets of intermediate weight coefficients;
to determine weight coefficients of the antennas as the products of the two respective sets of intermediate weight coefficients and √{square root over (P/M)}, wherein P represents limited power of the antennas; and
to perform beamforming for the two sets of antennas by the weight coefficients of the antennas.