Wireless transmission precoding
Embodiments of the present disclosure describe systems and methods for precoding wireless transmissions. Various embodiments may precode rank-one or rank-two wireless transmissions onto four antennas. Various embodiments may precode wireless transmissions using a precoding matrix selected from a group of matrices, wherein different groups of matrices differ in total angular region, number of beams, or angular distance between beams. Other embodiments may be described and/or claimed.
1. An apparatus for precoding wireless transmissions on four antennas, comprising:
one or more computing processors;
selection logic to be operated by the one or more computing processors to select, based on an indicator from a user equipment, a precoding matrix from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
precoding logic to be operated by the one or more computing processors to precode a rank-one wireless transmission in accordance with the selected precoding matrix; and
four antennas to transmit the precoded rank-one wireless transmission.
2. The apparatus of claim 1 , further comprising:
a touch screen display.
3. The apparatus of claim 1 , wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.
4. The apparatus of claim 1 , further comprising:
reception logic to receive the indicator from the user equipment, wherein the indicator specifies a particular precoding matrix to be selected by the selection logic.
5. The apparatus of claim 4 , further comprising:
one or more antennas, coupled with the reception logic, to receive the indicator from the user equipment.
6. One or more computer readable media having instructions thereon which, when executed by one or more processing devices of an apparatus, cause the apparatus to:
select, based on an indicator from a user equipment, a precoding matrix from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
and
precode a rank-one wireless transmission in accordance with the selected precoding matrix; and
transmit the precoded rank-one wireless transmission.
7. The one or more computer readable media of claim 6 , wherein the one or more processing devices are included in a System on Chip.
8. The one or more computer readable media of claim 6 ,
wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.
9. The one or more computer readable media of claim 6 , further having instructions thereon which, when executed by the one or more processing devices of the apparatus, cause the apparatus to:
receive the indicator from the user equipment, wherein the indicator specifies a particular precoding matrix to be selected by the apparatus.
10. The one or more computer readable media of claim 6 , wherein the one or more computer readable media comprises a non-volatile memory.
11. An apparatus for indicating a selected precoding matrix, comprising:
one or more computing processors;
selection logic to be operated by the one or more computing processors to select a precoding matrix, for precoding a rank-one wireless transmission on four antennas, from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
and
indicator logic to be operated by the one or more computing processors to provide an indicator of the selected precoding matrix for wireless transmission to an access node; and
transmission logic to wirelessly transmit the indicator to the access node.
12. The apparatus of claim 11 ,
wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.
13. The apparatus of claim 12 , further comprising:
one or more antennas to wirelessly transmit the indicator to the access node.
14. The apparatus of claim 11 , further comprising a global positioning system device.
15. One or more computer readable media having instructions thereon which, when executed by one or more processing devices of an apparatus, cause the apparatus to:
select a precoding matrix, for precoding a rank-one wireless transmission on four antennas, from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
and
provide an indicator of the selected precoding matrix for wireless transmission to an access node; and
wirelessly transmit the indicator to the access node.
16. The one or more computer readable media of claim 15 , wherein the one or more computer readable media comprises a non-volatile memory.
17. The one or more computer readable media of claim 15 ,
wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.
18. A method for precoding wireless transmissions on four antennas, comprising:
selecting, by a computing device based on an indicator from a user equipment, a precoding matrix from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
and
precoding, by the computing device, a rank-one wireless transmission in accordance with the selected precoding matrix; and
transmitting, by the computing device, the precoded rank-one wireless transmission.
19. The method of claim 18 ,
wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.
20. The method of claim 18 , further comprising:
receiving, by the computing device, the indicator from the user equipment, wherein the indicator specifies a particular precoding matrix to be selected by the computing device.
21. The method of claim 18 , wherein the computing device comprises an evolved NodeB(eNB).
22. A method for enabling wireless transmissions on four antennas, comprising:
selecting, by a computing device, a precoding matrix, for precoding a rank-one wireless transmission on four antennas, from a set of matrices, wherein the set of matrices are calculated by using elements of
{
[
Y
i
q
0
2
i
Y
i
]
,
[
Y
i
j
q
0
2
i
Y
i
]
,
[
Y
i
-
q
0
2
i
Y
i
]
,
[
Y
i
-
j
q
0
2
i
Y
i
]
}
,
for
i
=
0
,
1
,
2
,
3
;
q 0 =e j2π/32 , Y i =e i for i=0,1,2,3, where e i is a 4×1 vector with all zero entries except a unity at the i-th entry;
and
providing, by the computing device, an indicator of the selected precoding matrix for wireless transmission to an access node; and
wirelessly transmitting, by the computing device, the indicator to the access node.
23. The method of claim 22 , wherein the computing device is a user equipment.
24. The method of claim 22 ,
wherein the precoding matrix is selected from the set of matrices representable as
W k,0
W k,8
W k,16
W k,24
W k+8,2
W k+8,10
W k+8,18
W k+8,26
W k+16,4
W k+16,12
W k+16,20
W k+16,28
W k+24,6
W k+24,14
W k+24,22
W k+24,30
where
W
m
,
n
=
1
2
[
v
m
φ
n
v
m
]
,
φ
n
=
e
j
2
π
n
/
32
,
v
m
=
[
1
q
0
m
]
,
q
0
=
e
j
2
π
/
32
,
and
k
=
0
,
1
,
…
,
15.