Apparatus for orthogonal 16-QPSK modulated transmission
An apparatus, method and article of manufacture comprise a transceiver coupled to a phased array of antenna elements that are configured into pluralities of antenna elements to generate N modes of orthogonal radio waves where N is equal to or greater than 2. The coupling is via a plurality of 16-quadrature phase shift key (16-QPSK) modulators, each which is coupled to a respective one of the pluralities of antenna elements to modulate data onto a respective one of the N modes of orthogonal radio waves, to cause each of the N modes to operate as an independent data channel. For the case of N=2 modes, two 16-QPSK modulators generate independent 16-QPSK constellations, one for the first of the two modes and one for the second of the two modes, such that two 16-QPSK constellations are independent of each other, are orthogonal, and are on the same frequency.
1. An apparatus comprising:
a phased array of antenna elements configured into pluralities of antenna elements, the pluralities of antenna elements configured to generate N modes of orthogonal orbital angular momentum (OAM) radio waves where N is equal to or greater than 2; and
a plurality of quadrature phase shift key (QPSK) modulators, each of the plurality of QPSK modulators configured to receive data bits as input and coupled to a respective one of the pluralities of antenna elements to modulate QPSK symbols onto a respective one of the N modes of orthogonal OAM radio waves,
wherein each of the N modes of orthogonal OAM radio waves operates as an independent data channel,
wherein the apparatus is configured to transmit the modulated orthogonal OAM radio waves, each on a respective one of the pluralities of antenna elements,
wherein N=2 and a first of the QPSK modulators provides a first QPSK constellation for a first mode, and a second of the QPSK modulators provides a second QPSK constellation for a second mode,
wherein the first QPSK constellation and the second QPSK constellation are independent of each other, and
wherein the first QPSK constellation and the second QPSK constellation are orthogonal and are on the same frequency.
2. The apparatus of claim 1 wherein all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from respective constellation centers of the first QPSK constellation and the second QPSK constellation, all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from adjacent neighboring constellation points of the first QPSK constellation and the second QPSK constellation, and there is only one constellation symbol per constellation quadrate.
3. The apparatus of claim 1 wherein the first mode is mode M 0 and the second mode is mode M 1 , and both the first QPSK modulator and the second QPSK modulator are 16-QPSK modulators that operate on vectors:
ϕ
1
(
t
)
=
2
E
s
T
s
cos
(
wt
)
ϕ
2
(
t
)
=
2
E
s
T
s
sin
(
wt
)
and the waveform equation is:
S
(
t
)
=
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
0
+
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
1
where:
ϕ m (t) are QPSK basisvectors, where m is 1 or 2;
w is an angular frequency;
ψ M 0 is mode 0 two dimensional vector space;
ψ M 1 is mode 1 two dimensional vector space;
Es is symbol energy;
Ts is symbol period;
n is a quadrant number for respective ones of the first QPSK modulator and the second QPSK modulator, where n=1, 2, 3, 4; and
t is an independent variable representing a temporal quantity.
4. The apparatus of claim 1 wherein each of the plurality of QPSK modulators are 16-QPSK modulators and each of the 16-QPSK modulators receives two independent bits as input per time period.
5. The apparatus of claim 1 further comprising an antenna interface board configured to couple each QPSK modulator to a respective one of the pluralities of antenna elements, the antenna interface board comprising a respective plurality of phase shifters that provide phase shift to respective antenna elements of the respective one of the pluralities of antenna elements according to the equations:
d
ϕ
=
M
2
Π
N
e
ϕ
i
=
N
i
[
M
2
Π
N
e
]
where:
N e is the number of array elements and N e is at least 1 plus the mode number M;
M is the mode number and is an integer between [−(N e −1) and (N e −1)];
mode 0 is a conventional plane wave;
ϕ i is the phase shift for the i th antenna element; and
dϕ is the phase shift for the antenna element adjacent to the ith antenna element.
6. A method comprising:
activating an apparatus that comprises a plurality of quadrature phase shift key modulators coupled to a phased array of antenna elements configured into pluralities of antenna elements, the pluralities of antenna elements coupled to a plurality of phase shifters for generating N modes of orthogonal orbital angular momentum (OAM) radio waves where N is equal to or greater than 2; and
modulating QPSK symbols onto each of the N modes of orthogonal OAM radio waves by respective ones of the plurality of QPSK modulators, each of the respective ones of the plurality of QPSK modulators being coupled to a respective one of the pluralities of antenna elements to modulate the QPSK symbols onto a respective one of the N modes of orthogonal OAM radio waves,
wherein each of the N modes of orthogonal OAM radio waves operates as an independent data channel,
wherein the apparatus is configured to transmit the modulated orthogonal OAM radio waves, each on a respective one of the pluralities of antenna elements,
wherein N=2 and a first of the QPSK modulators provides a first QPSK constellation for a first mode, and a second of the QPSK modulators provides a second QPSK constellation for a second mode,
wherein the first QPSK constellation and the second QPSK constellation are independent of each other, and
wherein the first QPSK constellation and the second QPSK constellation are orthogonal and are on the same frequency.
7. The method of claim 6 wherein all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from respective constellation centers of the first QPSK constellation and the second QPSK constellation, all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from adjacent neighboring constellation points of the first QPSK constellation and the second QPSK constellation, and there is only one constellation symbol per constellation quadrate.
8. The method of claim 6 wherein the first mode is mode M 0 and the second mode is mode M 1 , and the QPSK modulators are 16-QPSK modulators that operate on vectors:
ϕ
1
(
t
)
=
2
E
s
T
s
cos
(
wt
)
ϕ
2
(
t
)
=
2
E
s
T
s
sin
(
wt
)
and the waveform equation is:
S
(
t
)
=
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
0
+
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
1
where:
ϕ m (t) are QPSK basis vectors, where m is 1 or 2;
w is an angular frequency;
ψ M 0 is mode 0 two dimensional vector space;
ψ M 1 is mode 1 two dimensional vector space;
Es is symbol energy;
Ts is symbol period;
n is a quadrant number for respective ones of the first QPSK modulator and the second QPSK modulator, where n=1, 2, 3, 4; and
t is an independent variable representing a temporal quantity.
9. The method of claim 6 wherein each of the plurality of QPSK modulators are 16-QPSK modulators and each of the 16-QPSK modulators receives two independent data bits as input per time period.
10. The method of claim 6 further comprising configuring an antenna interface board to couple each QPSK modulator to a respective one of the pluralities of antenna elements, the antenna interface board comprising the plurality of phase shifters for providing phase shift to respective antenna elements of the respective one of the pluralities of antenna elements according to the equations:
d
ϕ
=
M
2
Π
N
e
ϕ
i
=
N
i
[
M
2
Π
N
e
]
where:
N e is the number of array elements and N e is at least 1 plus the mode number M;
M is the mode number and is an integer between [−(N e −1) and (N e −1)];
mode 0 is a conventional plane wave;
ϕ i is the phase shift for the i th antenna element; and
dϕ is the phase shift for the antenna element adjacent to the ith antenna element.
11. One or more computer-readable hardware storage device having stored therein a set of instructions which, when executed by one or more processors of a computer, causes the computer to execute operations comprising:
activating an apparatus that comprises a plurality of quadrature phase shift key QPSK modulators coupled to a phased array of antenna elements configured into pluralities of antenna elements, each of the pluralities of antenna elements coupled to a plurality of phase shifters for generating N modes of orthogonal orbital angular momentum (OAM) radio waves where N is equal to or greater than 2; and
modulating QPSK symbols onto each of the N modes of orthogonal OAM radio waves by respective ones of the plurality of QPSK modulators, each of the respective ones of the plurality of QPSK modulators being coupled to a respective one of the pluralities of antenna elements to modulate the QPSK symbols onto a respective one of the N modes of orthogonal OAM radio waves,
wherein each of the N modes of orthogonal OAM radio waves operates as an independent data channel,
wherein the apparatus is configured to transmit the modulated orthogonal OAM radio waves, each on a respective one of the pluralities of antenna elements,
wherein N=2 and a first of the QPSK modulators provides a first QPSK constellation for a first mode, and a second of the QPSK modulators provides a second QPSK constellation for a second mode,
wherein the first QPSK constellation and the second QPSK constellation are independent of each other, and
wherein the first QPSK constellation and the second QPSK constellation are orthogonal and are on the same frequency.
12. The one or more computer-readable hardware storage device of claim 11 wherein all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from respective constellation centers of the first QPSK constellation and the second QPSK constellation, all constellation points of the first QPSK constellation and the second QPSK constellation are equidistant from adjacent neighboring constellation points of the first QPSK constellation and the second QPSK constellation, and there is only one constellation symbol per constellation quadrate.
13. The one or more computer-readable hardware storage device of claim 11 wherein the first mode is mode M 0 and the second mode is mode M 1 , and the QPSK modulators are 16-QPSK modulators that operate on vectors:
ϕ
1
(
t
)
=
2
E
s
T
s
cos
(
wt
)
ϕ
2
(
t
)
=
2
E
s
T
s
sin
(
wt
)
and the waveform equation is:
S
(
t
)
=
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
0
+
(
2
E
s
T
s
cos
(
wt
+
(
2
n
-
1
)
π
4
)
ψ
M
1
where:
ϕ m (t) are QPSK basis vectors, where m is 1 or 2;
w is an angular frequency;
ψ M 0 is mode 0 two dimensional vector space;
ψ M1 is mode 1 two dimensional vector space;
Es is symbol energy;
Ts is symbol period;
n is a quadrant number for respective ones of the first QPSK modulator and the second QPSK modulator, where n=1, 2, 3, 4; and
t is an independent variable representing a temporal quantity.
14. The one or more computer-readable hardware storage device of claim 11 wherein each of the plurality of QPSK modulators are 16-QPSK modulators and each of the 16-QPSK modulators receives two independent data bits as input per time period.
15. The one or more computer-readable hardware storage device of claim 11 , the operations further comprising configuring an antenna interface board to couple each QPSK modulator to a respective one of the pluralities of antenna elements, the antenna interface board comprising the plurality of phase shifters to provide phase shift to respective antenna elements of the respective one of the pluralities of antenna elements according to the equations:
dϕ=M 2Π/ N _ e
ϕ_ i=N _ i[M 2Π/ N _ e]
where:
Ne is the number of array elements and Ne is at least 1 plus the mode number M;
M is the mode number and is an integer between [−(N e −1) and (N e −1)];
mode 0 is a conventional plane wave;
ϕ_i is the phase shift for the i th antenna element; and
dϕ is the phase shift for the antenna element adjacent to the i th antenna element.