Method and Apparatus for Generating Codebooks and Associated
Data in a Network Device
Field of the Invention
The invention is related to wireless communication, particularly, to a
method and apparatus for generating data in the network device.
Background of the Invention
In practice, the cross-polarized linear array (CLA) is one kind of
antenna configuration. The polarization of the antenna means the direction of
intensity of the electrical field when the antenna is radiating. Such electrical
wave is referred to as a vertical polarized wave when the direction of intensity
of the electrical field is perpendicular to the ground; Such electrical wave is
referred to as a horizontal polarized wave when the direction of intensity of the
electrical field is parallel to the ground. The cross-polarized antenna is a
bi-polarized antenna.
In FDD systems, the transmitter of a mobile network device obtains the
channel information via quantization and limited feedback from each user. A
codebook based on Channel Status Indicator (CSI) quantization is widely used
in LTE and LTE-A systems. In recent 3GPP RANI meetings, the
cross-polarized linear array is determined to have the highest priority, and
accordingly, the codebook of multiple antennas including the 4Tx codebook
needs to be enhanced for performance improvement.
Summary of the Invention
For a MIMO system with n (n is an even number) transmission antennas
in a CLA configuration, the antennas may be divided into two sub-groups, i.e.,
two groups of different polarization antennas, where the first group of
polarization antennas is on the same polarization direction, and the secondgroup of polarization antennas is on the other polarization direction. For the
first group of polarization antennas, the array response shows the form of a
DFT vector. However, due to the existence of cross-polarization discrimination
(XPD), the CLA channel does not appear a constant modulus property as a
uniform linear array (ULA) channel. This means that there are amplitude and
phase differences between the two antenna sub-groups.
Based on the research and analysis above, inventors of the invention
realized that the polarization property of the cross-polarized linear antenna
array is not considered thoroughly in existing methods of the codebook
generation, that is, there is not only a relative phase offset, but also a relative
amplitude difference between different polarization antennas, thus there may
be a large error for the channel information feedback, which affects the system
performance. For the cross-polarized linear antenna array, when the mobile
equipment feeds back to the base station, the precoding matrix determined by
the base station may reflect downlink channel information more accurately if
the polarization property of the cross-polarized linear antenna array can be
considered thoroughly in the transmitted codeword, thereby improving the
system performance effectively.
Based on the concern above, in terms of the characteristic of CLA
configuration, it is proposed a method for generating a codebook for the
communication network in an embodiment of the invention, the
communication network being configured with a cross-polarized linear
antenna array, the cross-polarized linear antenna array comprising
cross-polarized first and second groups of antennas, the method comprising the
steps of: (a) generating a first row sub-matrix corresponding to the first group
of antennas respectively for respective ranks; wherein the respective ranks
corresponds to codebooks to be generated; (b) generating a second row
sub-matrix corresponding to the second group of antennas respectively for the
respective ranks based on an amount of the phase adjustment of the second
group of antennas with respect to the first group of antennas; and (c) generating
a second codebook in accordance with the first row sub-matrix and the secondrow sub-matrix.
By utilizing the codebook generated via the method above, it is
proposed a method for using the codebook as described above to generate data
in the network device in an embodiment of the invention, the network device
comprising a cross-polarized linear antenna array, the cross-polarized linear
antenna array comprising cross-polarized first and second groups of antennas,
the method comprising the steps of: A. receiving first codebook information
from a user equipment; B. determining a first codebook and a first codeword
therein in accordance with the first codebook information; C. generating a first
data in accordance with the first codeword, wherein the first codeword
corresponds to a first matrix, and the first and second row sub-matrices of the
first matrix correspond to the first group of antennas and the second group of
antennas respectively; with respect to the first row sub-matrix, the second row
sub-matrix reflects an amount of the phase adjustment of the second group of
antennas with respect to the first group of antennas; and the respective column
vectors of the first matrix are orthogonal.
It should be noted that the first group of antennas corresponds to the
first polarization direction, and the second group of antennas corresponds to
the second polarization direction, and the first polarization direction and the
second polarization direction is in a cross configuration. The first row
sub-matrix and the second row sub-matrix correspond to the first and the
second groups of antennas respectively, the first row sub-matrix and the second
row sub-matrix is respectively a row sub-matrix of the first matrix above, and
"the first" and "the second" do not indicate the positions where they are located
in the first matrix.
In addition, in accordance with an embodiment of the invention, it is
also proposed an apparatus for generating data in the network device, the
network device comprising a cross-polarized linear antenna array, the
cross-polarized linear antenna array comprising cross-polarized first and
second groups of antennas, the apparatus comprising: (a) a codebook
information receiving unit for receiving first codebook information from a userequipment; (b) a codebook codeword determination unit for determining a first
codebook and a first codeword therein in accordance with the first codebook
information; (c) a data generation unit for generating a first data in accordance
with the first codeword, wherein the first codeword corresponds to a first
matrix, and the first and second row sub-matrices of the first matrix correspond
to the first group of antennas and the second group of antennas respectively;
with respect to the first row sub-matrix, the second row sub-matrix reflects an
amount of the phase adjustment of the second group of antennas with respect to
the first group of antennas; and the respective column vectors of the first
matrix are orthogonal.
In accordance with an embodiment of the invention, it is also proposed
an apparatus for generating a codebook for the communication network, the
communication network being configured with a cross-polarized linear
antenna array, the cross-polarized linear antenna array comprising
cross-polarized first and second groups of antennas, the apparatus comprising:
(A) a first row sub-matrix generation unit for generating a first row sub-matrix
corresponding to the first group of antennas respectively for respective ranks;
(B) a second row sub-matrix generation unit for generating a second row
sub-matrix corresponding to the second group of antennas respectively for the
respective ranks based on an amount of the phase adjustment of the second
group of antennas with respect to the first group of antennas; and (C) a second
codebook generation unit for generating a second codebook in accordance with
the first row sub-matrix and the second row sub-matrix.
The method and apparatus of the embodiment of the invention reflect
the polarization property of the cross-polarized linear antenna array thoroughly,
the adjustments of the phase offset and the amplitude difference between
different polarization antennas are included in the procedure in which the data
to be transmitted is generated in some embodiments, so the feedback error of
the channel information is reduced greatly, and the system performance is
improved. The generation of the downlink-related data by the base station
reflects the downlink channel information more accurately.The aspects of the invention will be clearer through the specific
embodiments hereinbelow.
Brief Description of Drawings
The above and other features of the invention will be more clear
through reading the detailed description to the non-limiting embodiments in
conjunction with the reference to the drawings:
FIG. 1 is a flowchart of the method for generating data in a network
device in accordance with an embodiment of the invention;
FIG. 2 is a flowchart of the method for generating a codebook for the
communication network in accordance with an embodiment of the invention;
FIG. 3 is a functional block diagram of an apparatus for generating data
in the network device in accordance with the embodiment of an aspect of the
invention; and
FIG. 4 is a functional block diagram of an apparatus for generating a
codebook for the communication network in accordance with an embodiment
of an aspect of the invention.
In the drawings, like or similar reference numbers represent like or
similar components.
Detailed Description of Embodiments
It is assumed that a network device in the communication network is
configured with a cross-polarized linear antenna array. The cross-polarized
linear antenna array comprises first and second groups of antennas, the first
group of antennas corresponds to the first polarization direction, and the
second group of antennas corresponds to the second polarization direction, and
the first polarization direction and the second polarization direction are in
cross configuration. The first group of antennas above comprises the antennas
Al, A2, An; and the second group of antennas comprises the antennas Bl,
B2, Bn, wherein the antenna Al, A2, An are cross-polarized with the
antennas Bl, B2, Bn respectively.FIG. 2 is a flowchart of the method for generating a codebook for the
communication network in accordance with an embodiment of the invention.
By studying the characteristics of the cross-polarized antennas above and the
signals of the channels corresponding thereto, in the embodiment above, a
method of generation of the codebook proposed for the antenna configuration
of the communication network above comprises a step of the generation of the
first row sub-matrix S21, a step of the generation of the second row sub-matrix
S22, and a step of the generation of the second codebook S23.
In the step S21, for the respective ranks corresponding to the respective
codebooks to be generated, the first row sub-matrices corresponding to the first
group of antennas are generated respectively. For example, the specific form of
the first row sub-matrix may be the 1
st
to r
th columns of the matrix as shown in
the equation below if the rank of the codebook to be generated is r:
o v Vl-a 2v„ v 2N Vl-a 2v 2N
av Vl-a 2v
— —
N, N, N, N,
In the step S22, for the respective ranks, the second row sub-matrices
corresponding to the second group of antennas are generated respectively
based on the amount of the phase adjustment of the second group of antennas
with respect to the first group of antennas. For example, the second row
sub-matrix may be generated to be the 1
st
to r
th columns of the matrix as shown
in the equation below if the rank of the codebook to be generated is r:
Ν,
In the first row sub-matrix and the second row sub-matrix above,
indicates the amount of the phase adjustment above; r indicates the rank of the
codebook to be generated, r = ' '
N ; and " , for example, may be shown as
the equation below:where N indicates the number of the DFT beams of the first group of
antennas or the second group of antennas, and N' indicates the number of the
antennas configured by the network device.
In the step S23, in accordance with the first row sub-matrix and the
second row sub-matrix above, the second codebook is generated, for example,
if the rank of the codebook to be generated is r, then by combining the first row
sub-matrix and the second row sub-matrix above, the matrix corresponding to
the codewords of the second codebook may be shown as the 1
st
to r
th columns
of the equation below:
v„ Vl-a „ av N Vl-a v N
av Vl-a v
( 1) ( 1)
Ν, Ν, Ν, 2 Ν, 2
Vl-aV v - e
n Vl- Ν
-α ν 2Ν
l- Ν Ν
- e Ν Ν (— -1) ( -- 1)
Ν, Ν, Ν, 2 Ν, 2
It should be noted that the number of the columns of the matrix is only
illustrative, and the actual number of the columns of the matrix of the second
codebook in the above equation is the same as that of the rank of the second
codebook to be generated.
It is should also be noted that the amount of the amplitude adjustment of
the first group of antennas with respect to the second group of antennas or the
second group of antennas with respect to the first group of antennas is indicated
by using in a preferred manner in the embodiment herein, where 0 .
However, those skilled in the art should be appreciated that the second row
sub-matrix corresponding to the second group of antennas may also be
generated in terms of the respective ranks only based on the amount of the
phase adjustment of the second group of antennas with respect to the first
group of antennas or the amount of the phase adjustment of the first group of
antennas with respect to the second group of antennas in the step S22 of someembodiments of the invention. For example, optionally, if = 1/^, then the
codebook as described above is generated as a constant modulus matrix,
wherein the amount of the amplitude adjustment of the first group of antennas
with respect to the second group of antennas above is not reflected any more.
In addition, in the embodiment above, in accordance with the difference
of application scenarios, in the procedure of the generation of the codebook,
and may be caused to have different value space, such that the generated
codebooks have different volume. Generally, the preferred value may be a
value greater than 2 or 4, for example, for a procedure of the generation of the
scribed above, let =24 , i°-2' °
6' °
8'
9 , and
, then the volume of the generated codebook is 8.
Meanwhile, as a preferred implementation, in the method of the
embodiment above, for several second matrices corresponding to the
codewords of the second codebook, the setting of therein causes the
respective column vectors of the generated second matrix have the
characteristics of orthogonality and nesting. Of course, the setting of is not
limited to the form of the column vector above, and preferably, the
matrix/vector form which makes the respective column vectors of the
generated the second matrix orthogonal in the embodiment of the invention
above may be used in the invention.
Moreover, in the method of the embodiment above, a step of the
normalization of the matrix above may also be included. For example, the
matrix corresponding to the second codebook is further divided by , in order
to obtain the matrix form below, and the sub-matrix comprised of the 1
st
to
r
th columns of the matrix below is to be the codeword of the second
codebook, if the rank of the codebook to be generated is r:In the n in the equation above, in the case where the rank is 1, i.e.,
r=l as above, the codeword thereof is readily to be understood. While in the
method of the generation of the codebook, for the codeword in the case where
there is a high rank (r>l), the codebook as described above is generated based
on several beams which are orthogonal with each other by the method. Since
v v _L v
n therein has a DFT form, it is readily to derive that " ¾ when
n —n = K
, if the integer κ ≠ Because has a characteristic of
orthogonality and nesting, then the generated codebook also has the
characteristic above.
Moreover, in the method of the embodiment above, preferably, the step
S21 of the generation of the first row sub-matrix therein may further comprise
a step of the generation of the first row sub-matrix corresponding to the first
group of antennas by the DFT vector form in terms of the respective ranks. The
step S22 of the generation of the second row sub-matrix may further comprise
a step of the generation of the second row sub-matrix corresponding to the
second group of antennas on the basis of the DFT vector form in terms of the
respective rank respectively, based on the amount of the phase adjustment and
the amount of the amplitude adjustment of the second group of antennas with
respect to the first group of antennas as above. Next, in the step S23, a
preferred second codebook is generated in accordance with the generated first
and second row sub-matrices as above.
Using the method for generating the codebook for the communication
network above, a series of codebooks may be obtained, and at least part of
those codebooks have at least one characteristic as below due to the applicationof the method of the embodiment of the invention:
(1) In version 10, a plurality of cross-polarized antenna codebook has
large volume;
(2) The first and second row sub-matrices in the codeword of the
codebook above have the form of DFT vector respectively;
(3) There is certain amplitude adjustment and/or phase adjustment
between the first and second row sub-matrices of each codeword of the
codebook. Only certain phase adjustment is presented between the first and
second row sub-matrices of each codeword of the generated codebook, if the
codebook needs to maintain characteristics of constant modulus.
(4) The codebook has characteristics of orthogonality and nesting,
which is an advantageous characteristic in the engineering application.
The codebook generated by the method above may be used to generate
the associated data, such as a precoding matrix, etc., even further generate at
least one data stream transmitted by a transmission antenna of the eNB.
FIG. 1 is a flowchart of the method for generating data in a network
device in accordance with an embodiment of the invention. The description of
the application scenario of the generation of the associated data by using the
codebook is made in some embodiments of the invention in conjunction with
FIG. 1 hereinbelow. The method as shown in FIG. 1 comprises the step Sl l of
the receiving of the first codebook information, the step S12 of the
determination of the first codebook and the codeword, and the step SI 3 of the
generation of data.
In step Sll, the eNB receives the first codebook information from the
user equipment.
In step SI , the eNB determines the first codebook and the first
codeword therein in accordance with the first codebook information.
In step SI 3, the first data is generated in accordance with the first
codeword. The first data is, for example, a precoding matrix, which then may
be used to combine with data to be transmitted so as to generate data streamsthat can be transmitted to a downlink channel through the antenna subsequently.
The further usage of the first data is readily understood by those skilled in the
art, and will be omitted herein.
Wherein the first codeword corresponds to the first matrix, the first and
second row sub-matrices of the first matrix corresponds to the first and second
groups of antennas respectively; With respect to the first row sub-matrix, the
second row sub-matrix reflects the amount of the phase adjustment of the
second group of antennas with respect to the first group of antennas; and the
respective column vectors of the first matrix are orthogonal. For example, the
first matrix above may be a sub-matrix comprised of the 1
st
to r
th columns of the
matrix as shown in the equation below if the rank of the codebook to be
generated is r:
ocv, ocv OCV
«+ —-1)
2 2
The second row sub-matrix may also be a sub-matrix comprised of the
I
s
to r columns of the matrix below:
where in the first row sub-matrix and the second row sub-matrix above,
indicates the amount of the phase adjustment above; r indicates the rank of the
r = 1 2 • • • N V
codebook to be generated, ' ' ' ; and " , for example, may be shown
as the equation below:
where Ν indicates the number of the DFT beams of the first group of
antennas or the second group of antennas, and N' indicates the number of theantennas configured by the network device.
Thereby, if the rank of the codebook to be generated is r, the sub-matrix
of the 1
st
to r
th columns of the matrix below that is combined by the first and
second row sub-matrices above may be taken as the first matrix corresponding
to the first codeword for the generation of the associated data by the eNB:
Optionally, the matrix above may be set to be nested for the advantage
of the engineering application.
Again, as the first matrix corresponding to the first codeword, the
number of the columns of the matrix above is equal to the rank indication from
the user equipment.
In the embodiment above, the first codebook information may comprise
a rank indication and a codeword indication. The first matrix may be a matrix
normalized in accordance with the rank indication, for example, the first matrix
may be a matrix that is generated by dividing the matrix as shown in the
equation above by .
Take an example that the eNB is configured with 4 antennas, i.e., the
first group of antennas comprises the antenna Al and A2, and has the first
polarization direction; while the second group of antennas comprises the
antenna Bl and B2, and has the second polarization direction. Wherein the
antenna Al is cross-polarized with the antenna Bl , and the antenna Al is
cross-polarized with the antenna B2,
y
Let be a DFT vector with N points, which represents the phase
relationship between the antenna elements on the same polarization direction
1
1 e
N n = 0,l, N - l
Corresponding to 4 cases where the rank r
,4 Q s m a c
corresponding to the respective codewords of the codebook above may be thesub-matrices comprised of the column, the to the 2 columns, the I
s
to
the 3
rd columns, and the 1
st
to the 4
th columns of the matrix as shown in the
equation below respectively:
= 0,l, ---,N - l
Where and indicate the adjustments of amplitude and phase
between the two sub-groups. Since has the characteristics of orthogonality
and nesting, then the codebook and the matrix thereof also have the
characteristics of orthogonality and nesting, which is beneficial for the practice
application.
1
= - =
It is set that , if " above has a constant modulus, such that the
matrix of the codebook corresponding to rank 4 may be shown as the equation
below:
For the matrices of the codebook corresponding to rank r = , then
the 1
st
, 2
nd
, and 3
rd columns of
n in the equation above may be taken.
Although the description of some embodiments of the invention is made
by the application scenario of the eNB configured with 4 transmission antennas
in the communication network herein, those skilled in the art will be
appreciated that the specific number of the antennas is not a limitation to the
invention.
In another embodiment of the invention, the step S12 may further
comprise steps of the determination of the first codebook in accordance with
the rank indication, and the determination of the first codeword from the first
codebook in accordance with the codeword indication.
Furthermore, optionally, the first and second row sub-matrices in the
embodiment above may be in the DFT vector form, wherein with respect to the
first row sub-matrix, the second row sub-matrix both reflects the amount of theamplitude adjustment of the second group of antennas with respect to the first
group of antennas and the amount of the phase adjustment therebetween.
In the experiment conducted in accordance with the embodiment above,
the system experiment is performed over a 19 site cells (57 pentagon sectors).
The parameters and conditions of the experiment are shown in table 1.
Table 1 experiment parameters and premisesDownlink Synchronous HARQ, maximum 4 transmissions
HARQ
Control Fixed 0.3063 (as agreed in ITU evaluation)
channel and
reference
signal
overhead
Test 300 frames
configuration
The comparison of system performance between the proposed
codebook in some embodiments of the invention and the Rel-10 codebook is
shown in table 2.
Table 2 experiment resultGain of 28.7% 23.7%
proposed
over Rel-10
The result of the experiment illustrates that the proposed codebook in
the embodiments of the invention exceeds the Rel-10 codebook in
consideration of MU-MIMO and CoMP (scenario 2) modes, which improves
the gains of average cell spectral efficiency and cell edge user spectral
efficiency by 24%-29% and 14%-24% respectively.
FIG. 3 is a functional block diagram of an apparatus 100 for generating
data in the network device in accordance with the embodiment of an aspect of
the invention. The apparatus 100 may be disposed in the eNB, and comprises a
codebook information receiving unit 101, a codebook codeword determination
unit 102, and a data generation unit 103.
The codebook information receiving unit 101 is for receiving first
codebook information from a user equipment.
The codebook codeword determination unit 102 is for determining a
first codebook and a first codeword therein in accordance with the first
codebook information.
The data generation unit 103 is for generating a first data in accordance
with the first codeword.
Wherein the first codeword corresponds to the first matrix, the first and
second row sub-matrices of the first matrix corresponds to the first and second
groups of antennas respectively; with respect to the first row sub-matrix, the
second row sub-matrix reflects an amount of the phase adjustment of the
second group of antennas with respect to the first group of antennas; and the
respective column vectors of the first matrix are orthogonal.
Optionally, the first and second row sub-matrices above are in the DFT
vector forms, and with respect to the first row sub-matrix, the second row
sub-matrix expresses both the amount of the phase adjustment of the second
group of antennas with respect to the first group of antennas, and the amount ofthe amplitude adjustment of the second group of antennas with respect to the
first group of antennas, in order to be adaptive for different channel conditions.
FIG. 4 is a functional block diagram of an apparatus 200 for generating
the codebook for the communication network in accordance with an
embodiment of an aspect of the invention. The apparatus 200 may be disposed
in eNB, or disposed in other devices. After the codebook is generated, the
codebook is delivered to the eNB or the user equipment that needs to use it. The
apparatus 200 comprises a first row sub-matrix generation unit 201, a second
codebook generation unit 202, and a second row sub-matrix generation unit
203.
The first row sub-matrix generation unit 201 is for generating a first row
sub-matrix corresponding to the first group of antennas respectively for the
respective ranks.
The second row sub-matrix generation unit 202 is for generating a
second row sub-matrix corresponding to the second group of antennas
respectively for the respective ranks based on an amount of the phase
adjustment of the second group of antennas with respect to the first group of
antennas.
The second codebook generation unit 203 is for generating a second
codebook in accordance with the first row sub-matrix and the second row
sub-matrix.
Optionally, the second codebook above is a matrix, and there is
orthogonality between the respective column vectors in the matrix, and
preferably, the second codebook may also be configured to be nested.
For the skilled in the art, it is apparent that the invention is not limited to
the details of the above illustration embodiment, and the invention can be
implemented by other specific implementations without departing from the
spirit or elementary feature of the invention. Therefore, despite of any point,
the embodiments should be construed to be illustrative, and not limitation, and
any reference number in the claims should not be considered as the limitation
to the claim involved. Moreover, obviously, the terms "comprise" and"comprising" are not exclusion of other elements or steps, and the terms "a",
"an" and "the" are not exclusion of "plural" such elements. A plurality of
elements recited in the products claims may also be implemented through
software or hardware by an element. The terms "first" and "second" and so on
are used to indicate the names, and not to indicate any certain order.CLAIMS
1. A method for generating data in a network device, the network device
comprising a cross-polarized linear antenna array, the cross-polarized linear
antenna array comprising cross-polarized first and second groups of antennas,
the method comprising the steps of:
A. receiving first codebook information from a user equipment;
B. determining a first codebook and a first codeword therein in accordance
with the first codebook information;
C. generating a first data in accordance with the first codeword;
wherein the first codeword corresponds to a first matrix, and the first and
second row sub-matrices of the first matrix correspond to the first group of
antennas and the second group of antennas respectively; with respect to the
first row sub-matrix, the second row sub-matrix reflects an amount of the phase
adjustment of the second group of antennas with respect to the first group of
antennas; and the respective column vectors of the first matrix are orthogonal.
2. The method in accordance with claim 1, wherein the first codebook is set
to be nested.
3. The method in accordance with claim 1 or 2, wherein the first codebook
information comprises a rank indication and a codeword indication; the first
matrix is a matrix normalized in accordance with the rank indication.
4. The method in accordance with claim 3, wherein step B further
comprises the steps of:
determining the first codebook in accordance with the rank indication;
determining the first codeword from the first codebook in accordance with
the codeword indication.
5. The method in accordance with claim 1 or 2, wherein the first and second
row sub-matrices have DFT vector forms, and with respect to the first row
sub-matrix, the second row sub-matrix reflects an amount of the amplitude
adjustment and the amount of the phase adjustment of the second group of
antennas with respect to the first group of antennas.6. The method in accordance with claim 5, wherein the first matrix is the
l~r columns of a matrix as shown in the equation below,
where indicates the amount of the amplitude adjustment, < a < l • θ
indicates the amount of the phase adjustment; r indicates the rank indication,
r - l,2,- --,N t
.
an j
\n
-
a
q a
on below,
v.
11 e
N
• • •
N , n = 0,1,•••, N - l
, where Ν indicates the
number of DFT beams of the first group of antennas or the second group of
antennas, and N indicates the number of antennas configured by the network
device.
7. The method in accordance with claim 6, wherein =1/^ , and the size
of the first codebook is greater than 2 bits.
8. A method for generating a codebook for a communication network, the
communication network being configured with a cross-polarized linear
antenna array, the cross-polarized linear antenna array comprising
cross-polarized first and second groups of antennas, the method comprising the
steps of:
generating a first row sub-matrix corresponding to the first group of
antennas respectively for respective ranks; wherein the respective ranks
corresponds to codebooks to be generated;
generating a second row sub-matrix corresponding to the second group of
antennas respectively for the respective ranks based on an amount of the phase
adjustment of the second group of antennas with respect to the first group of
antennas;
generating a second codebook in accordance with the first and second rowsub-matrices.
9. The method in accordance with claim 8, wherein the second codebook is
a second matrix, the respective column vectors of the second matrix are
orthogonal, and the second codebook is set to be nested.
10. The method in accordance with claim 8 or 9, wherein the method
further comprises a step of normalizing the second matrix.
11. The method in accordance with claim 8 or 9, wherein the step of
generation of the first row sub-matrix further comprises the steps of:
generating the first row sub-matrix corresponding to the first group of
antennas with a DFT vector form for the respective ranks respectively;
wherein the step of the generation of the second row sub-matrix further
comprises the steps of:
generating the second row sub-matrix corresponding to the second group of
antennas on the basis of the DFT vector form for the respective ranks
respectively, based on the amount of the phase adjustment and an amount of the
amplitude adjustment of the second group of antennas with respect to the first
group of antennas.
12. An apparatus for generating data in a network device, the network
device comprising a cross-polarized linear antenna array, the cross-polarized
linear antenna array comprising cross-polarized first and second groups of
antennas, the apparatus comprising:
a codebook information receiving unit for receiving first codebook
information from a user equipment;
a codebook codeword determination unit for determining a first codebook
and a first codeword therein in accordance with the first codebook information;
a data generation unit for generating a first data in accordance with the first
codeword;
wherein the first codeword corresponds to a first matrix, and the first and
second row sub-matrices of the first matrix correspond to the first group of
antennas and the second group of antennas respectively; with respect to the
first row sub-matrix, the second row sub-matrix reflects an amount of the phaseadjustment of the second group of antennas with respect to the first group of
antennas; and the respective column vectors of the first matrix are orthogonal.
13. The apparatus in accordance with claim 12, wherein the first and second
row sub-matrices have DFT vector forms, and with respect to the first row
sub-matrix, the second row sub-matrix reflects the amount of the amplitude
adjustment and the amount of the phase adjustment of the second group of
antennas with respect to the first group of antennas.
14. An apparatus for generating a codebook for a communication network,
the communication network being configured with a cross-polarized linear
antenna array, the cross-polarized linear antenna array comprising
cross-polarized first and second groups of antennas, the apparatus comprising:
a first row sub-matrix generation unit for generating a first row sub-matrix
corresponding to the first group of antennas respectively for respective ranks;
a second row sub-matrix generation unit for generating a second row
sub-matrix corresponding to the second group of antennas respectively for the
respective ranks based on an amount of the phase adjustment of the second
group of antennas with respect to the first group of antennas;
a second codebook generation unit for generating a second codebook in
accordance with the first and second row sub-matrices.
15. The apparatus in accordance with claim 14, wherein the second
codebook is a second matrix, the respective column vectors of the second
matrix are orthogonal, and the second codebook is set to be nested.