Communication devices for multiple group communications
A base station for communicating with multiple groups of wireless communication devices is described. The base station includes a processor and executable instructions stored in memory that is in electronic communication with the processor. The base station determines a number of wireless communication devices. The base station also splits the number of wireless communication devices into groups. The base station further determines a precoding matrix for each group. The base station additionally transmits a beamformed signal to each group using the precoding matrix for each group.
1. A base station for communicating with multiple groups of wireless communication devices, comprising:
a processor;
memory in electronic communication with the processor;
instructions stored in the memory, the instructions being executable to:
determine a number of wireless communication devices;
split the number of wireless communication devices into groups;
determine a precoding matrix for each group, wherein determining the precoding matrix for each group comprises determining a complement group channel, determining a complement group channel null space, and determining a precoding matrix for a current group based on a client channel and the complement group channel null space for each wireless communication device; and
transmit a beamformed signal to each group using the precoding matrix for each group.
2. The base station of claim 1 , wherein determining the precoding matrix for each group is performed for beamforming an omnidirectional part of a preamble.
3. The base station of claim 1 , wherein the instructions are further executable to receive channel information.
4. The base station of claim 1 , wherein determining the precoding matrix for each group further comprises:
determining a group channel for the current group; and
determining the client channel for each wireless communication device in the current group.
5. The base station of claim 4 , wherein determining the complement group channel null space is accomplished according to an equation [U′,S′,V′]=svd(H′ k ), wherein H′ k is the complement group channel, U′ includes left singular vectors of H′ k , S′ are singular values of H′ k , V′ includes right singular vectors of H′ k , svd( )is a singular value decomposition function and the complement group channel null space V n comprises the last N tx −(N rxt −N rxk ) columns of V′, wherein N tx is a number of base station transmitters, N rxt is a total number of wireless communication device receivers and N rxk is a total number of receivers in a group k.
6. The base station of claim 4 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m , S m , V m ]=svd(H mk V n ) and W k (:, m)=V m (:,1)S -1 m (1,1) , wherein H mk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, W k is the precoding matrix for a group k and m is an index number.
7. The base station of claim 4 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m , S m , V m ]=svd(H mk V n ), Z(:, (m−1)N ssmk +1:m*N ssmk )=V m (:, 1:N ssmk )S m (1:N ssmk , 1:N ssmk ) and
W
km
=
(
ZZ
H
+
(
1
SNR
k
)
I
)
-
1
Z
,
wherein H mk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, N ssmk is a number of spatial streams of a wireless communication device m in a group k, Z is a matrix comprising selected eigenmodes, superscript H denotes a conjugate transpose, I is an identity matrix, SNR k is an estimate of average signal-to-noise ratio (SNR) in downlink for the group k and W km is the precoding matrix.
8. The base station of claim 4 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m , S m , V m ]=svd(H mk V n ), D m =V m (:, 1N ssmk )S m (1:N ssmk ,1:N ssmk), Z=[D 1 D m−1 D m=1 D N ck ] H , [U mz ,S mz , V mz ]=svd(Z), [U,S,V]=svd(D H m V mz (:, N ssk −N ssmk =1:N ssk )) and
W
km
=
V
mz
(
:
,
N
ssk
-
N
ssmk
)
V
(
(
I
N
ssmk
SNR
k
)
+
S
)
-
1
,
wherein H mk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, N ssmk is a number of spatial streams of a wireless communication device m in a group k, D m is a steering vector for the wireless communication device m, Z is a matrix of steering vectors to all wireless communication devices in the group k H besides the wireless communication device m, superscript H denotes a conjugate transpose, N ck is a number of wireless communication devices in the group k, U mz includes left singular vectors of Z, S mz are singular values of Z, V mz includes right singular vectors of Z, U includes left singular vectors of D m H V mz (:, N ssk −N ssmk +1:N ssk ), S are singular values of D m H V mz (:,N ssk −N ssmk +1:N ssk ), V includes right singular vectors of D m H V mz (N ssk −N ssmk +1:N ssk ), N ssk is a number of spatial streams for the group k, I N ssmk is an identity matrix with N ssmk rows and columns, SNR k is an estimate of average signal-to-noise ratio (SNR) in downlink for the group k and W km is the precoding matrix.
9. The base station of claim 4 , wherein determining the precoding matrix for the current group is accomplished by setting H ck to V″ c (:, 1:N ssck ) H , wherein H ck is a channel for a wireless communication device c in a group k, V″ c is a beamforming matrix for the wireless communication device c, N ssck is a number of spatial streams for the wireless communication device c in the group k and superscript H denotes a conjugate transpose.
10. The base station of claim 4 , wherein determining the precoding matrix for the current group is accomplished by setting H ck to S″ c (1:N ssck ,1:N ssck )V″ c (:, 1: N ssck ) H , wherein H ck is a channel for a wireless communication device c in a group k, V″ c is a beamforming matrix for the wireless communication device c, S″ c are singular values for the wireless communication device c, N ssck is a number of spatial streams for the wireless communication device c in the group k and superscript H denotes a conjugate transpose.
11. The base station of claim 1 , wherein the precoding matrix for the current group is applied to a first part of a preamble, and wherein the instructions are further executable to determine a second precoding matrix for the current group that is applied to a second part of the preamble.
12. A method for communicating with multiple groups of wireless communication devices by a base station, comprising:
determining a number of wireless communication devices;
splitting the number of wireless communication devices into groups;
determining a precoding matrix for each group, wherein determining the precoding matrix for each group comprises determining a complement group channel, determining a complement group channel null space, and determining a precoding matrix for a current group based on a client channel and the complement group channel null space for each wireless communication device; and
transmitting a beamformed signal to each group using the precoding matrix for each group.
13. The method of claim 12 , wherein determining the precoding matrix for each group is performed for beamforming an omnidirectional part of a preamble.
14. The method of claim 12 , further comprising receiving channel information.
15. The method of claim 12 , wherein determining the precoding matrix for each group further comprises:
determining a group channel for the current group; and
determining the client channel for each wireless communication device in the current group.
16. The method of claim 15 , wherein determining the complement group channel null space is accomplished according to an equation [U′,S′,V′]=svd(H′ k ), wherein H′ k is the complement group channel, U′ includes left singular vectors of H′ k , S′ are singular values of H′ k , V′ includes right singular vectors of H′ k , svd( )is a singular value decomposition function and the complement group channel null space V n comprises the last N tx −(N rxt −N rxk ) columns of V′, wherein N txk is a number of base station transmitters, N rxt is a total number of wireless communication device receivers and N rxk is a total number of receivers in a group k.
17. The method of claim 15 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m ,S m ,V m ]=svd(H mk V n ) and W k (:, m)=V m (:,1)S m −1 (1,1), wherein H mk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, W k is the precoding matrix for a group k and m is an index number.
18. The method of claim 15 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m , S m , V m ]=svd(H mk V n ), Z(:, (m−1)N ssmk +1:m*N ssmk )=V m (:, 1:N ssmk )S m (1:N ssmk , 1: N ssmk ) and
W
km
=
(
ZZ
H
+
(
1
SNR
k
)
I
)
-
1
Z
,
wherein H mk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, N ssmk is a number of spatial streams of a wireless communication H device m in a group k, Z is a matrix comprising selected eigenmodes, superscript H denotes a conjugate transpose, I is an identity matrix, SNR k is an estimate of average signal-to-noise ratio (SNR) in downlink for the group k and W km is the precoding matrix.
19. The method of claim 15 , wherein determining the precoding matrix for the current group is accomplished according to equations [U m ,S m ,V m ]=svd(H mk V n ), D m =V m (:,1:N ssmk )S m (1:N ssmk ,1:N ssmk ), Z=[D 1 D m−1 D m+1 D N ck ] H , [U mz , S mz , V mz ]=svd(Z), [U,S,V]=svd(D m V H V mz (:, N ssk −N ssmk +1:N ssk )) and
W
km
=
V
mz
(
:
,
N
ssk
-
N
ssmk
)
V
(
(
I
N
ssmk
SNR
k
)
+
S
)
-
1
,
wherein H mkk is the client channel, V n is the complement group channel null space, U m includes left singular vectors of H mk V n , S m are singular values of H mk V n , V m includes right singular vectors of H mk V n , svd( )is a singular value decomposition function, N ssmk is a number of spatial streams of a wireless communication device m in a group k, D m is a steering vector for the wireless communication device m, Z is a matrix of steering vectors to all wireless communication devices in the group k besides the wireless communication device m, superscript denotes a conjugate transpose, N ck is a number of wireless communication devices in the group k, U mz includes left singular vectors of Z, S mz are singular values of Z, V mz includes right singular vectors of Z, U includes left singular vectors of D m H V mz (:,N ssk −N ssmk +1:N ssk ), S are singular values of D m H V mz (:,N ssk −N ssmk +1:N ssk ), V includes right singular vectors of D m H V mz (:,N ssk −N ssmk +1:N ssk ), N ssk is a number of spatial streams for the group k, I N ssmk is an identity matrix with N ssmk rows and columns, SNR k is an estimate of average signal-to-noise ratio (SNR) in downlink for the group k and W km is the precoding matrix.
20. The method of claim 12 , wherein the precoding matrix for the current group is applied to a first part of a preamble, and wherein the method further comprises determining a second precoding matrix for the current group that is applied to a second part of the preamble.
21. The method of claim 12 , further comprising:
sending multiple channel state information requests using at least one common antenna for different channel state information requests to a same wireless communication device;
receiving multiple channel state information messages from the same wireless communication device; and
combining the multiple channel state information messages.
22. The method of claim 15 , wherein determining the precoding matrix for the current group is accomplished by setting H ck to V″ c (:,1:N ssck ) H , wherein H ck is a channel for a wireless communication device c in a group k, V″ c is a beamforming matrix for the wireless communication device c, N ssck is a number of spatial streams for the wireless communication device c in the group k and superscript H denotes a conjugate transpose.
23. The method of claim 15 , wherein determining the precoding matrix for the current group is accomplished by setting H ck to S″ c (1:N ssck ,1:N ssck )V″ c (:,1:N ssck ) H , wherein H ck is a channel for a wireless communication device c in a group k, V″ c is a beamforming matrix for the wireless communication device c, S″ c are singular values for the wireless communication device c, N ssck is a number of spatial streams for the wireless communication device c in the group k and superscript H denotes a conjugate transpose.
24. A computer-program product for communicating with multiple groups of wireless communication devices, comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:
code for causing a base station to determine a number of wireless communication devices;
code for causing the base station to split the number of wireless communication devices into groups;
code for causing the base station to determine a precoding matrix for each group, wherein determining the precoding matrix for each group comprises determining a complement group channel, determining a complement group channel null space, and determining a precoding matrix for a current group based on a client channel and the complement group channel null space for each wireless communication device; and
code for causing the base station to transmit a beamformed signal to each group using the precoding matrix for each group.
25. The computer-program product of claim 24 , wherein determining the precoding matrix for each group is performed for beamforming an omnidirectional part of a preamble.
26. The computer-program product of claim 24 , wherein determining the precoding matrix for each group further comprises:
determining a group channel for the current group; and
determining the client channel for each wireless communication device in the current group.
27. The computer-program product of claim 24 , the instructions further comprising:
code for causing the base station to send multiple channel state information requests using at least one common antenna for different channel state information requests to a same wireless communication device;
code for causing the base station to receive multiple channel state information messages from the same wireless communication device; and
code for causing the base station to combine the multiple channel state information messages.
28. An apparatus for communicating with multiple groups of wireless communication devices, comprising:
means for determining a number of wireless communication devices;
means for splitting the number of wireless communication devices into groups;
means for determining a precoding matrix for each group, wherein the means for determining the precoding matrix for each group comprises means for determining a complement group channel, means for determining a complement group channel null space, and means for determining a precoding matrix for a current group based on a client channel and the complement group channel null space for each wireless communication device; and
means for transmitting a beamformed signal to each group using the precoding matrix for each group.
29. The apparatus of claim 28 , wherein determining the precoding matrix for each group is performed for beamforming an omnidirectional part of a preamble.
30. The apparatus of claim 28 , wherein the means for determining the precoding matrix for each group further comprises:
means for determining a group channel for the current group; and
means for determining the client channel for each wireless communication device in the current group.
31. The apparatus of claim 28 , further comprising:
means for sending multiple channel state information requests using at least one common antenna for different channel state information requests to a same wireless communication device;
means for receiving multiple channel state information messages from the same wireless communication device; and
means for combining the multiple channel state information messages.
32. A method for communicating in a system with a base station and multiple groups of wireless communication devices, comprising:
determining a number of wireless communication devices;
splitting the number of wireless communication devices into groups;
determining a precoding matrix for each group, wherein determining the precoding matrix for each group comprises determining a complement group channel, determining a complement group channel null space, and determining a precoding matrix for a current group based on a client channel and the complement group channel null space for each wireless communication device;
transmitting a beamformed signal to each group using the precoding matrix for each group;
receiving a group signal, wherein the group signal includes information for two or more wireless communication devices; and
recovering data for a wireless communication device from the group signal using spatial filtering.