U.S. patent application number 13/297941 was filed with the patent office on 2013-05-16 for system and method for increased bandwidth efficiency within microwave backhaul of a telecommunication system.
This patent application is currently assigned to METROPCS WIRELESS, INC.. The applicant listed for this patent is SOLYMAN ASHRAFI. Invention is credited to SOLYMAN ASHRAFI.
Application Number | 20130121330 13/297941 |
Document ID | / |
Family ID | 48146109 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130121330 |
Kind Code |
A1 |
ASHRAFI; SOLYMAN |
May 16, 2013 |
SYSTEM AND METHOD FOR INCREASED BANDWIDTH EFFICIENCY WITHIN
MICROWAVE BACKHAUL OF A TELECOMMUNICATION SYSTEM
Abstract
An apparatus for transmitting information in a wireless
communication system includes a first interface for receiving a
plurality of input data streams. Signal processing circuitry
transmits and receives the plurality of input data streams on at
least one frequency. Each of the plurality of input data streams on
the at least one frequency have a different orbital angular
momentum imparted thereto.
Inventors: |
ASHRAFI; SOLYMAN; (PLANO,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASHRAFI; SOLYMAN |
PLANO |
TX |
US |
|
|
Assignee: |
METROPCS WIRELESS, INC.
RICHARDSON
TX
|
Family ID: |
48146109 |
Appl. No.: |
13/297941 |
Filed: |
November 16, 2011 |
Current U.S.
Class: |
370/343 ;
370/310 |
Current CPC
Class: |
H04L 5/04 20130101; H04W
72/044 20130101; H04J 1/08 20130101 |
Class at
Publication: |
370/343 ;
370/310 |
International
Class: |
H04B 7/00 20060101
H04B007/00; H04J 1/08 20060101 H04J001/08 |
Claims
1. An apparatus for transmitting information in a wireless
communications system, comprising: a first interface for receiving
a plurality of input data streams; signal processing circuitry for
transmitting and receiving the plurality of input data streams on a
single RF frequency of a radio frequency channel, each of the
plurality of input data streams on the single RF frequency having a
different orbital angular momentum imparted thereto, wherein the
signal processing circuitry further comprises: first signal
processing circuitry for imparting the different orbital angular
momentum to each of the plurality of input data streams; a signal
combiner for combining at least a portion of the plurality of input
data streams having the different orbital angular momentum onto the
single RF frequency; and a transmitter for transmitting the single
RF frequency having the plurality of different orbital angular
momentums therein over the radio frequency channel; a second
interface for outputting the single frequency having the plurality
of input data streams each having the different orbital angular
momentum imparted thereto.
2. (canceled)
3. The apparatus of claim 1, wherein the first signal processing
circuitry generates a different current for each of the plurality
of input data streams for imparting the different orbital angular
momentum to an input data stream.
4. The apparatus of claim 1, wherein the signal processing
circuitry further comprises: a receiver for receiving the at least
one frequency having the plurality of different orbital angular
momentums therein over the radio frequency channel; signal
separator circuitry for separating each of the plurality of input
data streams having the different orbital angular momentum from the
received single frequency; and second signal processing circuitry
for removing the different orbital angular momentum from each of
the plurality of input data streams.
5. The apparatus of claim 1 further including a
modulator/demodulator for modulating and demodulating the input
data streams.
6. (canceled)
7. A wireless communications system for transmitting information
over a wireless backhaul of a telecommunications system,
comprising: first transceiver circuitry for transmitting a
plurality of frequencies over an RF communications link of the
wireless backhaul, wherein the first transceiver circuitry
transmits a plurality of data streams on each of the plurality of
frequencies, each of the plurality of data streams transmitted with
a unique orbital angular momentum associated therewith; second
transceiver circuitry for receiving the plurality of frequencies
over the RF communications link of the wireless backhaul, wherein
the second transceiver circuitry extracts from each of the
plurality of frequencies the plurality of data streams having the
unique orbital angular momentum associated therewith.
8. The wireless communications system of claim 7, wherein the first
transceiver circuitry further comprises: first signal processing
circuitry for generating the unique orbital angular momentum
associated with each of the plurality of data streams; a signal
combiner for combining each of the plurality of data streams having
the different orbital angular momentum onto at least one frequency;
and a transmitter for transmitting the at least one frequency
having the plurality of different orbital angular momentums therein
over the RF communications link of the wireless backhaul.
9. The apparatus of claim 8 wherein the first signal processing
circuitry generates a different current for each of the plurality
of input data streams for imparting the unique orbital angular
momentum to an input data stream.
10. The wireless communications system of claim 9, wherein the
second transceiver circuitry further includes: a receiver for
receiving the at least one frequency having the plurality of
different orbital angular momentums therein over the RF
communications link of the wireless backhaul; signal separator
circuitry for separating each of the plurality of data streams
having the unique orbital angular momentum associated therewith
from the received at least one frequency; and second signal
processing circuitry for removing the unique orbital angular
momentum from each of the plurality of input data streams.
11. The wireless communications system of claim 7 further including
a first antenna for transmitting the plurality of frequencies
having the plurality of input data streams, each of the plurality
of input data streams having the unique orbital angular momentum
therein responsive to information contained in the input data
stream.
12. The wireless communications system of claim 11 further
including a second antenna for receiving the plurality of
frequencies having the plurality of input data streams having the
unique orbital angular momentum therein.
13. A wireless communications link for carrying information between
a transmission point and a receiving point in a wireless backhaul
of a wireless communications system, comprising: a plurality of
frequencies interconnecting the transmission point and the
receiving point on an RF communications link; a plurality of data
streams combined together onto at least one of the plurality of
frequencies; and wherein each of the plurality of data streams on a
same frequency of the plurality of frequencies have a unique
orbital angular momentum associated therewith.
14. The wireless communications link of claim 13, wherein each of
the plurality of data streams have a unique current associated
therewith for generating the unique orbital angular momentum.
15. A method for transmitting data, comprising: receiving a
plurality of data streams; imparting a unique orbital angular
momentum to each of the plurality of data streams; combining at
least a portion of the plurality of data streams having the unique
orbital angular momentum applied thereto onto a single frequency of
an RF communications link; and transmitting the single frequency
including the portion of the of data streams having the unique
orbital angular momentum applied thereto over the RF communications
link.
16. The method of claim 15 wherein the step of imparting further
comprises: generating a unique current for each of the plurality of
data streams; and applying the generated unique current to each of
the plurality of data streams.
17. (canceled)
18. The method of claim 15 further comprising the step of receiving
the at least one frequency including the plurality of input data
streams having the unique orbital angular momentum associated
therewith over the RF communications link.
19. The method of claim 18, wherein the step of receiving further
comprises the steps of: receiving the at least one frequency
including the plurality of input data streams having a unique
orbital angular momentum over the RF communications link;
separating each of the plurality of input data streams having the
unique orbital angular momentum from the received at least one
frequency; and second signal processing circuitry for removing the
unique orbital angular momentum from each of the plurality of input
data streams.
Description
TECHNICAL FIELD
[0001] The present invention relates to the microwave/satellite
backhaul connections within a wireless telecommunication system,
and more particularly, to a method for increasing the bandwidth
within the microwave/satellite backhaul using multiple signals
having different orbital angular momentums transmitted upon a same
frequency.
BACKGROUND
[0002] Within wireless telecommunication systems, signals are
transmitted from the base stations, which are in direct
communications with the plurality of mobile devices within the
telecommunications system to various network provider components,
such as HLRs, MSC/VLR and base station controllers on conventional
2G & 3G networks and HSS, MME, CPG on new 4G networks. These
components are in some cases interconnected via a backhaul
connection that utilizes T1, Ethernet or variety of access methods
including microwave or satellite links for providing the
information between those components of the service provider's
network. All such mediums are bandwidth limited, but more so on
satellite or microwave links. These satellite or microwave links
are bandwidth limited, according to the number of radio frequencies
that are available within the connections. The ability to transmit
additional information on the available microwave or satellite
bandwidth without interfering with signals already being
transmitted over the connections would greatly benefit the service
providers by increasing their effective bandwidth without actually
requiring additional frequencies in order to boost the system
capacity.
SUMMARY
[0003] The present invention, as disclosed and described herein, in
one aspect thereof, comprises an apparatus for transmitting
information in a wireless communication system. A first interface
receives a plurality of input data streams. Signal processing
circuitry transmits and receives the plurality of input data
streams on at least one frequency. Each of the plurality of input
data streams on the at least one frequency have a different orbital
angular momentum imparted thereto. A second interface outputs the
at least one frequency having the plurality of input data streams
each having the different orbital angular momentum imparted
thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] For a more complete understanding, reference is now made to
the following description taken in conjunction with the
accompanying Drawings in which:
[0005] FIG. 1 is a block diagram of a wireless telecommunication
system;
[0006] FIG. 2 comprises a functional block diagram of the manner
for transmitting multiple data streams on a same frequency of an
antennae according to the present disclosure;
[0007] FIG. 3 illustrates the manner in which multiple data streams
may be processed to apply an orbital angular momentum to the
signal, enabling transmission of multiple signals on a single
frequency;
[0008] FIG. 4 illustrates the manner for receiving a single
frequency, including multiple data streams having different orbital
angular momentums within the single frequency to provide the
multiple data streams;
[0009] FIG. 5 illustrates how various signals having different
orbital angular momentums may be utilized on a single
frequency;
[0010] FIG. 6a illustrates a plane wave having spins applied
thereto;
[0011] FIG. 6b illustrates a signal having both spin and orbital
angular momentum applied thereto;
[0012] FIGS. 7a-7c illustrate how signals having different orbital
angular momentums may be used for generating differing signals on
the same frequency;
[0013] FIG. 7d illustrates the propagation of a pointing vector for
various Eigen modes;
[0014] FIG. 8 illustrates an antenna for providing signals with a
variable orbital angular momentum; and
[0015] FIG. 9 illustrates the spiral phase plate of the antenna
used for transmitting the signals according to the present
disclosure.
DETAILED DESCRIPTION
[0016] Referring now to the drawings, wherein like reference
numbers are used herein to designate like elements throughout, the
various views and embodiments of a system and method for increased
bandwidth efficiency within microwave backhaul of a
telecommunication system are illustrated and described, and other
possible embodiments are described. The figures are not necessarily
drawn to scale, and in some instances the drawings have been
exaggerated and/or simplified in places for illustrative purposes
only. One of ordinary skill in the art will appreciate the many
possible applications and variations based on the following
examples of possible embodiments.
[0017] Referring now to FIG. 1, there is illustrated the network in
which the below-described system may be used to provide the mobile
backhaul with increased bandwidth. The RF portion of this system,
including a cellular tower 102 and SIU 104, provides a means for
wireless communication devices to interface with the provider
network. The mobile backhaul section 106 provides for a connection
between the SIU 104 and a metro Ethernet 108. The connection
between the SIU 104 and metro Ethernet 108 may consist of a
microwave connection 110, copper wire connection 112 or fiber
connection 114. By utilizing the system, as described hereinbelow,
the bandwidth over the microwave connection 110 between the SIU 104
and metro Ethernet 108 may be increased. The metro Ethernet 108
connects signals over the mobile backhaul 106 to/from a T1
aggregate 116 and GE (Gigabit Ethernet) lines 118 to the CPG/E-AGG
(Combined serving and packet gateways/Aggregation router) 120. The
CPG/E-AGG 120 provides a connection to an IP core 122 for providing
IP communications.
[0018] Referring now to FIG. 2, there is illustrated a general
functional block diagram of the system of the present disclosure
wherein the inclusion of an orbital angular momentum "twist" to a
provided data stream may be used to transmit multiple data streams
upon the same frequency. This increases the bandwidth over a
microwave or satellite communications link within the backhaul
structure. Multiple data streams 202 are provided to the
transmission processing circuitry. Each of these data streams 202
comprises, for example, an end-to-end voice link connection
carrying a voice call or a packet connection transmitting
non-circuit switch packet data over a data connection. The multiple
data streams 202 are processed by the modulator/demodulator
circuitry 204. The modulator/demodulator 204 modulates the received
data stream 202 onto a radio frequency channel that is transmitted
over a microwave or satellite connection over the backhaul
communications links discussed previously with respect to FIG.
1.
[0019] The modulated data stream is provided to the OAM (Orbital
Angular Momentum) signal processing block 206. Each of the
modulated data streams from the modulator/demodulator 204 are
provided a different orbital angular momentum by the OAM signal
processing block 206 such that each of the modulated data streams
have a unique and different orbital angular momentum associated
therewith. Each of the modulated signals having an associated
orbital angular momentum are provided to an antenna 208 that
transmits each of the modulated data streams having a unique
orbital angular momentum on a same frequency. Each frequency having
a selected number of bandwidth slots B may have its data
transmission capability increased by a factor of the number of
degrees of orbital angular momentum L that are provided from the
OAM signal processing block 206. Thus, the antenna transmitting
signals at a single frequency could transmit B groups of
information. The antenna 208 and OAM signal processing block 206
may transmit L.times.B groups of information according to the
configuration described herein.
[0020] In the receiving mode, the antenna 208 will receive a
frequency, including multiple signals transmitted therein having
differing orbital angular momentum signals embedded therein. The
antenna 208 forwards these signals to the OAM (Orbital Angular
Momentum) signal processing block 206 which separate each of the
signals having different orbital angular momentums and provides the
separated signals to the modulator/demodulator circuitry 204. The
demodulation process then extracts the data stream 202 from the
modulated signal and provides it at the receiving end.
[0021] Referring now to FIG. 3, there is provided a more detailed
functional description of the OAM signal processing block 206. Each
of the input data streams are provided to OAM circuitry 302. Each
of the OAM circuitries 302 provides a different orbital angular
momentum to the received data stream. The different orbital angular
momentums are achieved by applying differing currents for the
generation of the signals that are being transmitted to create a
particular orbital angular momentum associated therewith. The
orbital angular momentum provided by each of the OAM circuitries
302 are unique to the data stream that is provided thereto. An
infinite number of orbital angular momentums may be attributed to
different input data streams generated many a different current.
Each of the separately-generated data streams are provided to a
signal combiner 304 which combines the signals onto the same
frequency for transmission from the transmitter 306.
[0022] Referring now also to FIG. 4, there is illustrated the
manner in which the OAM processing circuitry 206 may separate a
received backhaul signal into the multiple data streams. The
receiver 402 receives the combined OAM signals on the single
frequency and provides this information to a signal separator 404.
Signal separator 404 separates each of the signals having different
orbital angular momentums from the received frequency and provides
them to OAM de-twisting circuitry 406. The OAM de-twisting
circuitry 406 removes the associated OAM twist from each of the
associated signals and provides the received modulated data stream
for further processing.
[0023] FIG. 5 illustrates the manner in which a single frequency
having two quantized spin polarizations may provide an infinite
number of signals having various orbital angular momentums
associated therewith. The I-axis represents the various orbital
angular momentum states which may be applied to a particular signal
at a selected frequency. Omega (w) represents the various
frequencies to which the signals of differing orbital angular
momentum may be applied. The top grid 502 represents the
potentially available signals for a left-hand (negative) signal
polarization while the bottom grid 504 is for potentially available
signals having a right-hand (positive) polarization.
[0024] By applying different orbital angular momentum states to a
signal at a particular frequency, a potentially infinite number of
states may be provided at the frequency. Thus, the state at the
frequency .DELTA..omega. 506 in both the left-hand polarization
plane 502 and right-hand polarization plane 504 can provide an
infinite number of signals at different orbital angular momentum
states .DELTA.I. Blocks 508 and 510 represent a particular signal
having an orbital angular momentum .DELTA.I at a frequency
.DELTA..omega. in both the right-hand polarization plane 504 and
left-hand polarization plane 510, respectively. By changing to a
different orbital angular momentum within the same frequency
.DELTA..omega. 506, a different signal may also be transmitted.
Each angular momentum state corresponds to a different determined
current level for transmission from the antennae. By estimating the
equivalent currents for generating a particular angular momentum
within the radio domain and applying this current for transmission
of the signal the transmission of the signal may then be achieved
at a desired orbital angular momentum state.
[0025] Thus, the illustration of FIG. 5, illustrates two possible
angular momentums, the spin angular momentum and the orbital
angular momentum. The spin version is manifested within
polarizations of macroscopic electromagnetism and has only left and
right hand polarizations due to up and down spin directions.
However, the orbital angular momentum includes an infinite number
of states that are quantized. An antennae having independent
channels from 1=-3 to 1=+3 is illustrated at 514. However, the
paths are more than two and can theoretically be infinite through
the quantized orbital angular momentum levels.
[0026] Using the orbital angular momentum state of the transmitted
energy signals, physical information can be embedded within the
electromagnetic radiation transmitted by the signals. The
Maxwell-Heaviside equations can be represented as:
.gradient. E = .rho. 0 ##EQU00001## .gradient. .times. E = -
.differential. B .differential. t ##EQU00001.2## .gradient. B = 0
##EQU00001.3## .gradient. .times. B = 0 .mu. 0 .differential. E
.differential. t + .mu. 0 j ( t , x ) the ##EQU00001.4##
where .gradient. is the del operator, E is the electric field
intensity and B is the magnetic flux density. Using these
equations, we can derive 23 symmetries/conserve quantities from
Maxwell's original equations. However, there are only ten
well-known conserve quantities and only a few of these are
commercially used. Historically if Maxwell's equations where kept
in their original quaternion forms, it would have been easier to
see the symmetries/conserved quantities, but when they were
modified to their present vectorial form by Heaviside, it became
more difficult to see such inherent symmetries in Maxwell's
equations.
[0027] Maxwell's linear theory is of U(1) symmetry with Abelian
commutation relations. They can be extended to higher symmetry
group SU(2) form with non-Abelian commutation relations that
address global (non-local in space) properties. The Wu-Yang and
Harmuth interpretation of Maxwell's theory implicates the existence
of magnetic monopoles and magnetic charges. As far as the classical
fields are concerned, these theoretical constructs are
psedoparticle, or instanton. The interpretation of Maxwell's work
actually departs in a significant ways from Maxwell's original
intention. In Maxwell's original formulation, Faraday's
electrotonic states (the A.mu. field) was central making them
compatible with Yang-Mills theory (prior to Heaviside). The
mathematical dynamic entities called solitons can be either
classical or quantum, linear or non-linear and describe EM waves.
However, solitons are of SU(2) symmetry forms. In order for
conventional interpreted classical Maxwell's theory of U(1)
symmetry to describe such entities, the theory must be extended to
SU(2) forms.
[0028] Besides the half dozen physical phenomena (that cannot be
explained with conventional Maxwell's theory), the recently
formulated Harmuth Ansatz also address the incompleteness of
Maxwell's theory. Harmuth amended Maxwell's equations can be used
to calculate EM signal velocities provided that a magnetic current
density and magnetic charge are added which is consistent to
Yang-Mills filed equations. Therefore, with the correct geometry
and topology, the A.mu. potentials always have physical meaning
[0029] The conserved quantities and the electromagnetic field can
be represented according to the .epsilon..sub.0 conservation of
system energy and the conservation of system linear momentum. Time
symmetry, i.e. the conservation of system energy can be represented
using Poynting's theorem according to the equations:
H = i m i .gamma. i c 2 + 0 2 .intg. 3 x ( E 2 + c 2 B 2 )
##EQU00002## U mech t + U em t + s ' 2 x ' n ^ ' S = 0
##EQU00002.2##
[0030] The space symmetry, i.e., the conservation of system linear
momentum representing the electromagnetic Doppler shift can be
represented by the equations:
.rho. = i m i .gamma. i v i + 0 .intg. 3 x ( E .times. B )
##EQU00003## p mech t + p em t + s ' 2 x ' n ' ^ T = 0
##EQU00003.2##
[0031] The conservation of system center of energy is represented
by the equation:
R = 1 H i ( x i - x 0 ) m i .gamma. i c 2 + 0 2 H .intg. 3 x ( x -
x 0 ) ( E 2 + c 2 B 2 ) ##EQU00004##
Similarly, the conservation of system angular momentum, which gives
rise to the azimuthal Doppler shift is represented by the
equation:
J mech t + J em t + s ' 2 x ' n ' ^ M = 0 ##EQU00005##
[0032] For radiation beams in free space, the EM field angular
momentum J.sup.em can be separated into two parts:
J.sup.em=.epsilon..sub.0.intg..sub.V'd.sup.3x'(E.times.A)+.epsilon..sub.-
0.intg..sub.V'd.sup.3x'E.sub.i[x'-x.sub.0).times..gradient.]A.sub.i
[0033] For each singular Fourier mode in real valued
representation:
J em = - i 0 2 .omega. .intg. V ' d 3 x ' ( E * .times. E ) - i 0 2
.omega. .intg. V ' 3 x ' E i [ ( x ' - x 0 ) .times. .gradient. ] E
i ##EQU00006##
[0034] The first part is the EM spin angular momentum S.sup.em, its
classical manifestation is wave polarization. And the second part
is the EM orbital angular momentum L.sup.em its classical
manifestation is wave helicity. In general, both EM linear momentum
P.sup.em, and EM angular momentum J.sup.em=L.sup.em+S.sup.em are
radiated all the way to the far field.
[0035] By using Poynting theorem, the optical vorticity of the
signals may be determined according to the optical velocity
equation:
.differential. U .differential. t + .gradient. S = 0 ,
##EQU00007##
where S is the Poynting vector
S = 1 4 ( E .times. H * + E * .times. H ) , ##EQU00008##
and U is the energy density
U = 1 4 ( E 2 + .mu. 0 H 2 ) , ##EQU00009##
with E and H comprising the electric field and the magnetic field,
respectively, and .epsilon. and .mu..sub.0 being the permittivity
and the permeability of the medium, respectively. The optical
vorticity V may then be determined by the curl of the optical
velocity according to the equation:
V = .gradient. .times. v opt = .gradient. .times. ( E .times. H * +
E * .times. H E 2 + .mu. 0 H 2 ) ##EQU00010##
[0036] Referring now to FIGS. 6a and 6b, there is illustrated the
manner in which a signal and its associated Poynting vector vary in
a plane wave situation where only the spin vector is altered, and a
situation wherein the spin and orbital vectors are altered as
described herein. In the plane wave situation illustrated generally
at 602 when only the spin vectors are altered, the transmitted
signal may take one of three configurations. When the spin vectors
are in the same direction, a linear signal is provided as
illustrated generally at 604. In linear polarization, the vectors
for the signal are in the same direction and have a same magnitude.
Within a circular polarization 606, the signal vectors are at 90
degrees to each other but have the same magnitude. Within the
elliptical polarization 608, the signal vectors are at 90 degrees
to each other but have differing magnitudes. The Poynting vector
maintains in a constant direction for the signal configurations of
FIG. 6a. Referring now to FIG. 6b, when a unique orbital angular
momentum is applied to a signal, its Poynting vector S 610 will
spiral about the general direction of propagation of the signal.
This spiral may be varied in order to enable signals to be
transmitted on the same frequency as described herein.
[0037] FIGS. 7a-7c illustrate the differences in signals having
different helicity (i.e., orbital angular momentums). Each of the
spiralizing Poynting vectors associated with the signals 702, 704
and 706 provide a different-shaped signal. Signal 702 has an
orbital angular momentum of plus one, signal 704 has an orbital
angular momentum of plus three and signal 706 has an orbital
angular momentum of minus four. Each signal has a distinct angular
momentum and associated Poynting vector enabling the signal to be
distinguished from other signals within a same frequency. This
allows differing types of information to be transmitted on the same
frequency since these signals are separately detectable and do not
interfere with each other.
[0038] FIG. 7d illustrates the propagation of Poynting vectors for
various Eigen modes. Each of the rings 720 represent a different
Eigen mode or twist representing a different angular momentum for a
same frequency. Each of these rings 720 represents a different
orthogonal channel. Each of the Eigen modes has a Poynting vector
722 associated therewith.
[0039] An antenna that may provide signals at a same frequency
having different angular momentums is illustrated in FIG. 8. The
antenna 802 includes a dish 804 having a generally circular
perimeter. The antenna dish 804 forms a helical plate. The plate
comprises a helical surface rising from a lowest segment 806 to a
highest segment 808 that are separated by a distance D. The
thickness of the antenna increases from the line 806 to the line
808 as you travel around the circumference of the dish. The antenna
802 will transmit signals having a selected orbital angular
momentum wherein the amount of orbital angular momentum is
proportionate to the current used for generating the antenna signal
from the antenna.
[0040] Referring now to FIG. 9, there is illustrated the manner in
which the antenna of FIG. 8 imparts an angular momentum to the
signal transmitted therefrom. The spiral phase plate 902 of the
antenna has a refractive index of N. The thickness of the phase
plate H 904 is proportional to the azimuthal position given by
.THETA.906. The spiral phase plate 902 enables signals transmitted
from the phase of the antenna to have differing angular momentums
associated therewith dependent upon the current that is used for
generating a particular signal associated with a data stream. Thus,
each data stream will be generated using a different current and
the spiral phase plate 902 operating in conjunction with the
current level used to generate the data stream at a particular
frequency will impart a unique orbital angular momentum to the
transmitted signal. In this manner, multiple data streams
transmitted using multiple current levels from the same spiral
phase plate will enable a single frequency to include multiple data
streams therein each having a different, unique orbital angular
momentum.
[0041] It will be appreciated by those skilled in the art having
the benefit of this disclosure that this system and method for
increased bandwidth efficiency within microwave backhaul of a
telecommunication system provides for the transmission of multiple
signals with differing orbital angular momentums. It should be
understood that the drawings and detailed description herein are to
be regarded in an illustrative rather than a restrictive manner,
and are not intended to be limiting to the particular forms and
examples disclosed. On the contrary, included are any further
modifications, changes, rearrangements, substitutions,
alternatives, design choices, and embodiments apparent to those of
ordinary skill in the art, without departing from the spirit and
scope hereof, as defined by the following claims. Thus, it is
intended that the following claims be interpreted to embrace all
such further modifications, changes, rearrangements, substitutions,
alternatives, design choices, and embodiments.
* * * * *