U.S. patent application number 17/509161 was filed with the patent office on 2022-02-10 for pointing algorithm for endpoint nodes.
The applicant listed for this patent is Starry, Inc.. Invention is credited to Joseph Thaddeus Lipowski.
Application Number | 20220045422 17/509161 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-10 |
United States Patent
Application |
20220045422 |
Kind Code |
A1 |
Lipowski; Joseph Thaddeus |
February 10, 2022 |
Pointing Algorithm for Endpoint Nodes
Abstract
A terrestrial high frequency data communication system and
method for implementing a pointing algorithm for endpoint nodes are
described. The system includes an aggregation node and one or more
endpoint nodes. In one example, a pointing direction for an
endpoint node is determined based on a number of packet error rate
(PER) measurements associated with a high frequency data
communication link between the endpoint node and an aggregation
node. Preferably, the endpoint node includes a steerable antenna
module that includes one or more antennas. The steerable antenna
module is configured to receive an azimuth value and an elevation
value determined based on PER measurements associated with the high
frequency data communication link, and to steer its one or more
antennas based on the azimuth value and the elevation value to
point to the aggregation node.
Inventors: |
Lipowski; Joseph Thaddeus;
(Norwell, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Starry, Inc. |
Boston |
MA |
US |
|
|
Appl. No.: |
17/509161 |
Filed: |
October 25, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15984713 |
May 21, 2018 |
11205842 |
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17509161 |
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62508539 |
May 19, 2017 |
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International
Class: |
H01Q 3/22 20060101
H01Q003/22; H04L 1/00 20060101 H04L001/00; H04B 7/0408 20060101
H04B007/0408; H04B 7/06 20060101 H04B007/06; H04B 7/08 20060101
H04B007/08 |
Claims
1. A high frequency data communication system, the system
comprising: an aggregation node; and at least one endpoint node
configured to communicate with the aggregation node via a high
frequency data communication link, wherein the endpoint node
includes a steerable antenna module that includes one or more
antennas, and wherein the steerable antenna module is configured
to: receive an azimuth value and an elevation value determined
based on packet error rate (PER) measurements associated with the
high frequency data communication link; and steer its one or more
antennas based on the azimuth value and the elevation value to
point to the aggregation node.
2. The system of claim 1, wherein the PER measurements are
performed for different azimuth and elevation values.
3. The system of claim 1, wherein the endpoint node and the
aggregation node communicate in a spectral band of 10 gigahertz
(GHz) to 300 GHz.
4. The system of claim 1, wherein the endpoint node and the
aggregation node communicate in a spectral band of 20 GHz to 60
GHz.
5. The system of claim 1, wherein the aggregation node comprises a
phased array antenna system that divides an area of coverage into
multiple subsectors.
6. The system of claim 5, wherein the phased array antenna system
includes at least one receive phased array antenna for receiving
information from the endpoint node.
7. The system of claim 5, wherein the phased array antenna system
includes at least one transmit phased array antenna for
transmitting information to the endpoint node.
8. The system of claim 1, wherein the one or more antennas of the
steerable antenna module are one or more patch array antennas.
9. The system of claim 1, wherein the one or more antennas of the
steerable antenna module are one or more parabolic dish antennas.
Description
RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. patent application
Ser. No. 15/984,713, filed on May 21, 2018, which claims the
benefit under 35 USC 119(e) of U.S. Provisional Application No.
62/508,539 filed on May 19, 2017, which are incorporated herein by
reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] In some areas, internet service providers (ISPs) use fixed
wireless network access technology to deliver network connectivity
to subscribers' premises. The ISPs transmit and receive data to and
from endpoint nodes at the subscribers' premises as radio waves via
transmission towers. This has been typically used in rural areas
where other networks, such as cable and optical fiber networks, are
not available.
[0003] Typically, interference from various entities and the noise
generated by these entities can negatively impact the
channel/signal quality of the wireless links between the ISPs and
the endpoint nodes.
SUMMARY OF THE INVENTION
[0004] In order to mitigate unwanted signal interference, an
improved pointing mechanism for the endpoint nodes is provided. The
pointing mechanism allows each endpoint node to accurately point to
an aggregation node, typically maintained by an ISP, to set up a
high quality data communication link with the aggregation node.
[0005] In particular, the proposed systems described herein utilize
terrestrial high frequency wireless data communication networks.
These networks typically operate in the 10 GHz to 300 GHz band for
communications between aggregation nodes and one or more high
frequency endpoint nodes such as fixed subscriber nodes and/or
multi-dwelling unit nodes, usually in star-topology networks.
[0006] Additionally, the technology of the proposed system also has
application to mobile and semi-mobile applications and
point-to-point links. This spectral band encompasses millimeter
wavelengths (mm-wave) that are traditionally described as covering
the 30 GHz to 300 GHz frequency band, and also extends to lower
frequencies to 10 GHz, for example.
[0007] In general, according to one aspect, the invention features
a high frequency data communications system such as a terrestrial
Extra High Frequency (EHF) data communication system operating in
the 10 GHz to 300 GHz band. The system comprises an aggregation
node and at least one endpoint node configured to communicate with
the aggregation node via a high frequency communications link. The
endpoint node includes a steerable antenna module that includes one
or more antennas. The steerable antenna module is configured to
receive an azimuth value and an elevation value determined based on
packet error rate (PER) measurements associated with the high
frequency data communication link, and to steer one or more of its
antennas based on the azimuth value and the elevation value to
point to the aggregation node.
[0008] Typically, the PER measurements are performed for different
azimuth and elevation values.
[0009] In one implementation, the aggregation node includes a
phased array antenna system that divides an area of coverage into
multiple subsectors. For this purpose, in one example, the phased
array antenna system includes at least one receive phased array
antenna for receiving information from the endpoint node. In
another example, the phased array antenna system includes at least
one transmit phased array antenna for transmitting information to
the endpoint node.
[0010] In examples, the one or more antennas of the steerable
antenna module can be one or more patch array antennas, or can be
one or more parabolic dish antennas.
[0011] In general, according to another aspect, the invention
features a method for determining a pointing direction for an
endpoint node in a terrestrial extra high frequency data
communication system. This method comprises determining a pointing
direction based on packet error rate (PER) measurements associated
with a high frequency data communication link between the endpoint
node and an aggregation node, and steering one or more antennas of
the endpoint node to point to the aggregation node according to the
pointing direction.
[0012] Preferably, determining the pointing direction comprises
determining azimuth and elevation values to be used for steering
the one or more antennas.
[0013] The method also comprises selecting a modulation and coding
scheme (MCS) level, measuring a PER at the MCS level, and adjusting
the pointing direction when the PER is greater than or equal to a
threshold value.
[0014] In one example, the method selecting the MCS level based on
a received signal strength indicator (RSSI) value and noise.
[0015] Typically, adjusting the pointing direction comprises
testing the PER at different azimuth values, and selecting a
particular azimuth value with a lowest PER. Adjusting the pointing
direction might also include testing the PER at the particular
azimuth value and different elevation values, and selecting a
particular elevation value with a lowest PER.
[0016] In another example, the method performs a tracking operation
when the PER is less than the threshold value. Typically,
performing the tracking operation comprises determining a tracked
azimuth value and a tracked elevation value based on packets
received over a period of time.
[0017] In general, according to yet another aspect, the invention
features an endpoint node that communicates with an aggregation
node via high frequency data communication links. The endpoint node
comprises a controller configured to determine a pointing direction
based on measurement of packet error rate (PER) at different
azimuth and elevation values, and a steerable antenna module
configured to steer one or more antennas based on the pointing
direction.
[0018] Preferably, the steerable antenna module includes a motor
unit that mechanically steers the one or more antennas. In
examples, the different azimuth values comprise an initial azimuth
value +/-1 beamwidth, and the different elevation values comprise
an initial azimuth value +/-1 beamwidth.
[0019] In examples, the controller might be further configured to
select a particular azimuth value of the different azimuth values
with a lowest PER, and to select a particular elevation value of
the different elevation values with a lowest PER.
[0020] Additionally, the steerable antenna module includes a
communication module that includes the one or more antennas. In one
example, the one or more antennas are integrated patch array
antennas with transceivers.
[0021] The above and other features of the invention including
various novel details of construction and combinations of parts,
and other advantages, will now be more particularly described with
reference to the accompanying drawings and pointed out in the
claims. It will be understood that the particular method and device
embodying the invention are shown by way of illustration and not as
a limitation of the invention. The principles and features of this
invention may be employed in various and numerous embodiments
without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In the accompanying drawings, reference characters refer to
the same parts throughout the different views. The drawings are not
necessarily to scale; emphasis has instead been placed upon
illustrating the principles of the invention. Of the drawings:
[0023] FIG. 1 is a block diagram showing an exemplary deployment of
an aggregation node and endpoint nodes in a terrestrial high
frequency communication system;
[0024] FIG. 2 is a perspective view of an endpoint node installed
at a subscriber's premise;
[0025] FIG. 3 is a perspective view with housing components of the
endpoint node shown in phantom;
[0026] FIG. 4 is a block diagram that shows components of the
endpoint node; and
[0027] FIGS. 5A-5C are flowcharts illustrating a pointing algorithm
for determining a pointing direction for the endpoint node, where
the flowchart of FIG. 5B provides detail for the flowchart of FIG.
5A, and where the flowchart of FIG. 5C provides detail for both the
flowcharts of FIG. 5A and FIG. 5B.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which illustrative
embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art.
[0029] As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items.
Further, the singular forms and the articles "a", "an" and "the"
are intended to include the plural forms as well, unless expressly
stated otherwise. It will be further understood that the terms:
includes, comprises, including and/or comprising, when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
Further, it will be understood that when an element, including
component or subsystem, is referred to and/or shown as being
connected or coupled to another element, it can be directly
connected or coupled to the other element or intervening elements
may be present.
[0030] A terrestrial high frequency communication system 100
illustrated in FIG. 1 shows an aggregation node (AN) 102 and a
plurality of high frequency network endpoint nodes (EN) 104, e.g.,
104-1, 104-2, . . . , and 104-n.
[0031] The aggregation node 102 utilizes a phased array antenna
system 103 to communicate with the endpoint nodes 104-1-104-n. The
antenna system 103 preferably covers an azimuthal arc of between
about 45 degrees and 180 degrees. Often, an azimuthal arc of about
120 degrees is used.
[0032] The operation of the phased array antenna system 103 then
divides the antenna's area of coverage into multiple subsectors S1,
S2, . . . , Sn. In the illustrated example, subsectors S1 through
S4 are distributed in an azimuthal fan, with the subsectors
adjoining one another. There are at least two subsectors; with some
embodiments having four, eight or more subsectors. As a result, in
typical implementations, each subsector S covers an azimuthal arc
of between possibly 8 degrees and 60 degrees. Currently, the
subsector azimuthal arc is between about 10 degrees and 25
degrees.
[0033] The phased array antenna system 103 forms transmit and
receive beams B1-Bn that correspond to each of the subsectors. In
this way, the aggregation node 102 reduces interference between
endpoint nodes, conserves power on the downlinks and reduces
transmit power requirements by the endpoint nodes on the uplinks.
Four exemplary transmit/receive beams B1 through B4 that correspond
to sectors S1 through S4, respectively, are shown.
[0034] The endpoint nodes EN 104 are distributed within and thereby
associated with different subsectors. For example, subscriber
endpoint nodes EN 104-1, 104-2, and 104-3 are associated with
subsector S1, subscriber endpoint nodes EN 104-4, 104-5, and 104-6
are associated with subsector S2, subscriber endpoint nodes EN
104-7 and 104-8 are associated with subsector S3, and subscriber
endpoint nodes EN 104-9 to 104-n are associated with subsector
S4.
[0035] In some embodiments, the phased array antenna system 103
produces a number of beams for the subscriber node/group of
subscriber nodes in each subsector S1, S2, Sn. The phased array
antenna system 103 typically includes one or more transmit phased
array antennas T for transmitting data streams to the endpoint
nodes 104 and one or more receive phased array antennas R for
receiving data streams from the endpoint nodes 104.
[0036] Each endpoint node 104 communicates with the aggregation
node 102 by means of an electronic assembly or system that provides
a wireless ISP (internet service provider) handoff at the premises
where the endpoint node 104 is installed. The endpoint node 104 is
a residential or business fixed wireless endpoint that communicates
with the aggregation node 102 via a terrestrial high frequency
network (i.e., using high frequency communication links/radios). In
some embodiments, the high frequency network operates between 10
and 300 GHz, or more commonly between about 20 and 60 GHz. In order
to receive the beams B1-Bn from the aggregation node 102, one or
more patch array antennas included in the electronic assembly at
the endpoint node 104 are steered to point at the aggregation node
102.
[0037] Locally each endpoint node 104, in a typical residential
implementation, communicates with a modem/router or access point
over possibly a WiFi tunnel (in the 2.4 or 5 GHz bands or the WiGig
tri-band in the 2.4, 5 and 60 GHz bands, or IEEE 802.11ac/IEEE
802.11ad-2012) or via a wired connection (e.g., 1000BASE-T). This
modem/router or access point then maintains the local area network
at the subscriber's premises.
[0038] In other cases, the endpoint node 104 itself maintains the
wired and/or wireless LAN at the premises. It provides typical
functions associated with LAN routers, such as Network Address
Translation (NAT), guest networks, Parental Controls and other
Access Restrictions, VPN Server and Client Support, Port Forwarding
and UPnP, and DHCP (Dynamic Host Configuration Protocol) server
that automatically assigns IP addresses to network devices on the
LAN.
[0039] According to a preferred embodiment, the aggregation node
102 includes multiple WiFi chipsets a, b, c n. These WiFi chipsets
are commercially available systems or assemblies of one or more
chips that implement the IEEE 802.11 standard as an access point.
These chipsets are capable of maintaining multiple downlink or
downlink and uplink spatial streams such as provided by the IEEE
802.11n or 802.11ac or 802.11ax versions and follow-on versions of
the standard. Each of these WiFi chipsets produce WiFi signals,
which are signals that have been encoded according to the IEEE
802.11 standard. These WiFi signals are then upconverted and
transmitted to the endpoint nodes 104. In turn, the endpoint nodes
transmit high frequency signals back, which signals are
downconverted to WiFi signals at the conventional frequencies such
as 2.4 or 5 GHz.
[0040] These WiFi chipsets are allocated to their own (e.g. one or
more) subsectors. Further, their WiFi signals are also preferably
up and down converted to different carrier frequencies to minimize
inter-chipset interference. Thus, for example, WiFi chipset "a"
might communicate with endpoint nodes in subsectors S1 and S2 at
frequency F1, whereas WiFi chipset "b" might communicate with nodes
in subsectors S3 and S4 at frequency F2.
[0041] FIG. 2 shows an example of an endpoint node 104
mounted/installed at a window 200 of a subscriber's premises, such
as a residence. The view of the figure is from the inside of the
residence. A lower sash 232 of a double hung window 200 is
shown.
[0042] The endpoint node 104 has an outdoor unit (ODU) 210 coupled
to an indoor unit (IDU) 220 by a bridge unit 230. This exemplary
endpoint node 104 is mounted in a manner similar to that of a
window air-conditioning unit. Specifically, with reference to the
illustrated double hung window 200, the subscriber node 104 is
placed on a windowsill 219 of the window 200. Then, a bottom rail
215 of the lower sash 232 is closed against a sealing member 208.
In particular, the bottom rail 215 of the lower sash 232 of the
window 200 clamps the sealing member 208 against the window's sill
219. This leaves the IDU 220 on the inside of the subscriber's
premises and the ODU 210 exposed on the outside of the subscriber's
premises (i.e., outside the window 200). The bridge unit 230
extends through the sealing member 208 and mechanically supports
both the ODU 210 and the IDU 220 on the windowsill 219. The bridge
unit 230 provides structural support for the assembly, as well as
acts as a conduit for electrical cables between the ODU 210 and the
IDU 220.
[0043] In other embodiments, the IDU 220 and ODU 210 are connected
by one or more cables, such as ribbon cables that extend under the
closed window 200, but are otherwise physically separated, and can
be detached from each other.
[0044] The ODU 210 is configured for high frequency communications
with the aggregation node 102, and the IDU 220 is configured for
WiFi communications (or wired connections or communications over
another unlicensed band) with one or more devices inside the
subscriber's premise. In some embodiments, the IDU 220 can
communicate with a router access point or directly with one or more
user devices at the subscriber's premise. The bridge unit 230
includes one or more interconnection cables for coupling the ODU
202 with the IDU 204, and a DC power module, e.g., one that can be
powered by a wall outlet.
[0045] On the other hand, in still other embodiments, the endpoint
nodes 104 are not separated into IDU 220, ODU 210, and bridge units
230. Instead, in one case, all of the necessary electronics are
contained within a single housing that is installed on an outer
wall or window of the premises. In one specific example, the
electronics of the ODU 210 and IDU 220 are contained in a
weatherproof case, which then magnetically mounts to the glass or
glazing of a window.
[0046] In other examples, the IDU 220 is located inside the
subscriber's premises on the interior side of an outer wall or near
an outer wall of the premises. The ODU 210 is located on an
exterior side of the outer wall. For example, in some
implementations, a hole is drilled through the outer wall such as
in the attic of the premises. In other examples, a hole is drilled
through the roof of the residence. Then, the ODU 210 is mounted on
the outside. The IDU 220 is mounted on an adjacent interior surface
of the roof or wall, such as mounted between rafters or studs.
[0047] FIG. 3 is a diagram of the endpoint node 102, in which the
enclosure components of the endpoint node 104 are shown in phantom
relative to window 200. The view of the figure is from the outside
of the residence, and the bottom sash 232 of the window 200 is
partially open. The ODU 210 is placed upon/mounted to an outside
portion of the windowsill 219.
[0048] The IDU 220 is coupled to the ODU 210 via the bridge unit
230 that projects through the sealing member 208. The IDU 220
includes a local wireless and/or wired module 310 that maintains a
wireless or wired local area network for the subscriber's premises.
In this case, the local wireless module 310 directly transmits and
receives information with network devices at the subscriber's
premise. In other cases, the local wireless module 310 transmits
and receives information with a local wireless access point/router
that then maintains the wireless local area network.
[0049] The ODU 210 includes an extremely high frequency (EHF)
communication module 320 (referred to hereinafter as an EHF module
320) that has one or more integrated patch array antennas with
transceivers, in one example. The EHF module 320 transmits and
receives information in high frequency signals to and from the
aggregation node 102. A servo controlled motor unit 322 supports
and mechanically steers the EHF module 320 (i.e., steers the patch
array antennas of the EHF module 320). A weather hardened enclosure
(referred to as a "Radome") 324 is designed for weather and UV
protection (i.e., to protect the EHF module 320 and motor unit 322
from weather conditions) but is transparent to the high
frequencies. In some embodiments, a heater (not shown) is also
installed within the enclosure 324. In some embodiments, the
combination of the EHF module 320 and the servo controlled motor
unit 322 can be referred to as a steerable antenna module 325.
[0050] The servo controlled motor unit 322 preferably includes a
2-axis pan-tilt mount or gimbal that is controlled by one or more
motors. The pan-tilt mount is used to rotate the EHF module 320 so
that the integrated patch array antenna can be accurately aligned
for communicating with the aggregation node 102. Specifically, the
motor unit 322 rotates the EHF module 320 around the vertical axis
or in an azimuth direction and further tips the EHF module 320
around a horizontal axis or in the elevation direction. This
movement allows the integrated patch array antenna(s) of the EHF
module 320 to be pointed at the phased array antenna system 103 of
the aggregation node 102.
[0051] This movement of the EHF module 320 also allows a dynamic
repositioning of the network without requiring site visits by
installers. For example, in the case of a failure of a particular
aggregation node 102 or the addition of a new aggregation node 102
to the overall local terrestrial network system (e.g., system 100),
the EHF module 320 will automatically re-point to a
secondary/backup/new aggregation node 102. Additionally, in the
case of a site that is served by multiple aggregation nodes 102, a
separate path may be extended facilitating redundancy and enabling
multi-path network coding to extend at the IP packet level.
[0052] In some embodiments, the motors (e.g., stepper motors) of
the motor unit 322 are controlled by a controller unit on the IDU
220. In one example, the motor unit 322 is capable of moving the
EHF module 320 to enable a 75 degree rotation or more in the
azimuth direction and a +25 degree rotation or more in the
elevation direction.
[0053] In some embodiments, the one or more antennas of the
steerable antenna module 325 may be parabolic dish antennas with or
without subreflectors, or one or more patch array antennas.
[0054] FIG. 4 is a block diagram of the endpoint node 104 showing
its components or modules. The components span across portions of
the endpoint node 104 including the IDU 220, bridge unit 230 and
ODU 210. The IDU 220 contains electronic circuits, primarily on two
printed circuit board assemblies (PCBAs) referred to as a WiFi
modem module 404 and a coupling module 402. The ODU 210 includes
the EHF module 320 and the servo controlled motor unit 322.
[0055] According to some embodiments, the WiFi modem module 404 is
a printed circuit board assembly, which includes: 1) a 802.11ac
4.times.4 radio chipset for the internet (referred to herein as
internet WiFi chipset 410), 2) a 802.11ac n.times.n chipset, such
as, (3.times.3) radio chip set (referred to herein as local WiFi
chipset or local wireless module 310) for establishing a wireless
data connection to a wireless router or access point via WiFi
antennas 416 on the IDU 220, and 3) and a Bluetooth low energy
(BLE) radio (not otherwise shown) for system configuration.
Preferably, the modem module 404 also includes one or more wired
and or optical network jacks such as optical fiber connectors or
RJ-45 jacks.
[0056] In one embodiment, off-the-shelf printed circuit board
assemblies (PCBAs) are used for the WiFi modem module 404 e.g.,
AP148 with 2 radio PCIe (Peripheral Component Interconnect Express)
modules. In some embodiments, the local WiFi chipset/local wireless
module 310 is mounted directly on the main PCB without
interconnections through inter-board connectors. In some
embodiments, a QCA9980 PCIe card that has a .about.5 GHz operating
frequency is used for the internet WiFi chipset 410.
[0057] Coupling module 402 couples the internet WiFi chipset 410
with the EHF module 320. In some embodiments, WiFi signals from the
internet WiFi chipset 410 are communicated to the EHF module 320
via the coupling module 402. The EHF module 320 receives the WiFi
signals from the coupling module 402, upconverts the WiFi
frequencies to high frequencies, and communicates with the
aggregation node 102 at the high frequencies. Similarly, the EHF
module 220 receives high frequency signals from the aggregation
node 102, downconverts the high frequency signals to WiFi signals,
and provides the WiFi signals to the coupling module 402 that in
turn provides the WiFi signals to the internet WiFi chipset 410.
The ODU 210 contains circuitries for the high frequency antennas,
frequency conversion, amplifiers, and LNBs (low noise block down
converters) on the EHF module 320. The LNB is a combination of
low-noise amplifier, frequency mixer, local oscillator and
intermediate frequency amplifier. RF signals, Tx/Rx control
signals, and serial signals are exchanged between the modem module
404 and the coupling module 402.
[0058] The IDU 220 includes a controller 425 that controls various
functions of the EHF module 320 and gimbal functions of the motor
unit 322. In some embodiments, the EHF module 320 measures the
signal strength/power associated with the high frequency signals
received from the aggregation node 102. This measurement is
referred to as a received signal strength indicator (RSSI) value
associated with the received high frequency signals. The EHF module
320 uses the RSSI value to determine an initial pointing direction
for the integrated patch array antennas(s) of the EHF module 320.
The initial pointing direction is communicated to the controller
425 via the coupling module 402. The controller 425 causes the
motor unit 322 to move the EHF module 320 (i.e., steer the
integrated patch array antenna(s)) in an azimuth and/or elevation
direction according to the initial pointing direction. In some
embodiments, packet error rate measurements are performed at the
initial pointing direction. These measurements are used to
determine a refined pointing direction. The controller 425 then
steers the integrated patch array antenna(s) according to the
refined pointing direction via the motor unit 322. The refined
pointing direction allows the antenna(s) to be steered such that
the signal quality of the link formed between the aggregation node
102 and the endpoint node 104 is enhanced.
[0059] Extending through the bridge unit 230 are cables supporting
two or more transmit connections TX and cables supporting two or
more receive connections RX, electrical connections for control and
status signals, power to the EHF module 320, and a motor control
harness between the controller 425 and the motor unit 322.
[0060] In some implementations, the radio on the modem module 404
has a TX Enable control signal that is asserted while the radio is
transmitting. The coupling module 402 buffers this signal, and
passes it along to the EHF module 320. In one embodiment, the radio
on the modem module 404 also has a RX Enable control signal that is
used to control the RX path of the SPDT (single pole double throw)
switch between the radio and its antenna. The coupling module 402
buffers this signal and passes it along to the EHF module 320. In
some implementations, T/R switches connect the unidirectional
transmission lines on the coupling module 402 to the bi-directional
transmission lines used on the modem module 404.
[0061] Further details regarding the high frequency system 100,
components of the aggregation node 102 and the endpoint node 104
and their deployment are described in detail in U.S. application
Ser. No. 15/418,256 filed on Jan. 27, 2017, entitled "Star Topology
Fixed Wireless Access Network", which is incorporated herein by
reference in its entirety.
[0062] FIGS. 5A-5C are flowcharts illustrating a pointing algorithm
for determining a pointing direction for the endpoint node 104 (in
particular, the EHF module 320 of the endpoint node 104). In some
embodiments, the modem module 404, controller 425, and the EHF
module 320, in collaboration, perform the various steps of FIGS.
5A-5C.
[0063] The pointing algorithm starts at step 502 in FIG. 5A. At
step 504, the EHF module 320 coarsely points towards the
aggregation node 102 using a compass heading. In some embodiments,
the controller 425 receives the coarse pointing direction from a
compass and points the EHF module 320 according to the coarse
pointing direction via the motor unit 322. In some embodiments, the
coarse pointing direction includes a coarse azimuth direction and a
coarse elevation direction.
[0064] At step 506, RSSI and noise measurements are performed at
the EHF module 320 while the EHF module 320 points in the coarse
pointing direction. In some embodiments, RSSI and noise values are
measured for high frequency signals received from the aggregation
node 102. The RSSI and noise values indicate channel conditions
associated with the high frequency data communication link between
the endpoint node 104 and the aggregation node 102. At steps 508
and 510, an Az-El grid (including the coarse azimuth and coarse
elevation directions) is adjusted and the corresponding RSSI values
at the adjusted azimuth and elevation directions are measured at
the EHF module 320. The adjusted Az-El grid values and the
corresponding RSSI values are added to a table maintained at the
EHF module 320.
[0065] At step 512, of the entries in the table, an Az-El grid with
the maximum RSSI value is selected. The selected azimuth and
elevation directions are communicated by the EHF module 320 to the
controller 425 via the coupling module 402. The controller 425
causes the motor unit 322 to move the EHF module 320 according to
the selected azimuth and elevation directions. These selected
azimuth and elevation directions are collectively referred to as
the initial pointing direction for the EHF module 320.
[0066] At step 514, a modulation and coding scheme (MCS) level or
index is selected based on the RSSI and noise measurements
associated with the initial pointing direction. In some
embodiments, the MCS level is selected from a set of MCS levels
supported by the 802.11ac standard. Each MCS level in the set
indicates at least a modulation type and a coding rate that can be
used for the high frequency data link.
[0067] At step 516, the modem module 404 in collaboration with or
independently of the controller 425, tests the packet error rate or
ratio (PER) at the selected MCS level. PER is defined as the number
of incorrectly received data packets divided by the total number of
received packets. When the calculated PER is greater than or equal
to a threshold value, a determination is made that the initial
pointing direction needs to be adjusted, which initiates a fine
adjustment operation at step 520. On the other hand, when the
calculated PER is less than the threshold value, a determination is
made that a tracking operation needs to be performed, which
initiates the tracking algorithm at step 560. The threshold value
is typically about 2.about.5%. The MCS level is chosen so that at
that level of Carrier to Noise Ratio, the result should be nearly
zero packet errors. If there are many more packet errors, then it
means that while Carrier to Noise Ratio is adequate, a more optimal
antenna alignment may find an alignment with less multipath
scattering and reflective obstructions and thus a more optimal
receiving condition may result.
[0068] FIG. 5B illustrates the steps of the fine adjustment
operation 520 in FIG. 5A.
[0069] At step 522, the initial azimuth value (associated with the
initial pointing direction) is permuted by +1 and -1 beamwidth. At
step 524, the PER measurements are performed at the target azimuth
MCS level (i.e., PER measurements associated with the permuted
azimuth values and the selected MCS level are performed). At step
526, a determination is made regarding which of the three PER
measurements (i.e., PER measurements associated with initial
unpermuted azimuth value, initial azimuth value +1 beamwidth, and
initial azimuth value -1 beamwidth) is lowest or about the same as
the maximum RSSI value. When the PER is lowest at initial azimuth
value +1 beamwidth, the azimuth value is set to an adjusted value
of initial azimuth value +1 beamwidth, at step 528. When the PER is
lowest at initial azimuth value -1 beamwidth, the azimuth value is
set to an adjusted value of initial azimuth value -1 beamwidth, at
step 530. When the PER is about equal or the lowest at the
unpermuted initial azimuth value, the azimuth value need not be
adjusted, and the method transitions to step 532. Upon completion
of steps 528 and 530, the method also transitions to step 532.
[0070] At step 532, PER measurements associated with unpermuted and
permuted elevation values are performed. With the azimuth value set
to one of the unpermuted initial azimuth, the initial azimuth value
+1 beamwidth, or initial azimuth value -1 beamwidth (as determined
at steps 528, 530, or 532), a first PER measurement is associated
with the unpermuted initial elevation value (i.e., initial
elevation value +/-0 beamwidth), a second PER measurement is
associated with the initial elevation value +1 beamwidth, and the
third PER measurement is associated with the initial elevation
value -1 beamwidth.
[0071] At step 534, a determination is made regarding which of the
three PER measurements (i.e., PER measurements associated with
unpermuted initial elevation value, initial elevation value +1
beamwidth, and initial elevation value -1 beamwidth) is lowest or
about the same as the maximum RSSI value. When the PER is lowest at
initial elevation value +1 beamwidth, the elevation value is set to
an adjusted value of initial elevation value +1 beamwidth, at step
536. When the PER is lowest at initial elevation value -1
beamwidth, the elevation value is set to an adjusted value of
initial elevation value -1 beamwidth, at step 538. When the PER is
about equal or the lowest at the unpermuted initial elevation
value, the elevation value need not be adjusted, and the method
transitions to step 540. Upon completion of steps 538 and 536, the
method also transitions to step 540.
[0072] At step 540, a determination is made regarding whether the
calculated PER is less than the threshold value. When the
calculated PER is less than the threshold value, a tracking
operation is commenced at step 560. In some embodiments, the fine
adjustment operation is performed/repeated until the calculated PER
is determined to be less than the threshold value.
[0073] On the other hand, when the calculated PER is greater than
or equal to the threshold value, a trial counter is incremented at
step 542. At step 544, a determination is made regarding whether a
number of trials has exceeded a predefined number. When the number
of trials has not exceeded the predefined number, the fine
adjustment operation is repeated starting at step 522.
[0074] When the number of trials has exceeded the predefined
number, the MCS level is decremented at step 546 and the algorithm
returns to step 516 in FIG. 5A, indicated by encircled reference
numeral A. Here, the modem module 404 in collaboration with or
independently of the controller 425, tests the PER at the
decremented MCS level. Either the fine adjustment operation or the
tracking operation can be commenced (at steps 520 and 560
respectively) based on whether the PER is greater than, equal to,
or less than the threshold value.
[0075] In some embodiments, the controller 425 causes the motor
unit 322 to move the EHF module 320 according to the finely
adjusted azimuth and elevation directions determined based on the
fine adjustment operation 520.
[0076] As a result, in one example, adjusting the pointing
direction of the endpoint node 104 includes testing the PER at
different azimuth values, and selecting a particular azimuth value
with a lowest PER. In another example, adjusting the pointing
direction includes testing the PER at the particular azimuth value
and different elevation values, and selecting a particular
elevation value with a lowest PER. For this purpose, the controller
425 is configured to select a particular azimuth value of the
different azimuth values with a lowest PER, and/or to select a
particular elevation value of the different elevation values with a
lowest PER.
[0077] FIG. 5C illustrates the steps of the tracking
algorithm/operation 560 in FIGS. 5A and 5B.
[0078] At step 562, an MCS level is automatically selected. The
current azimuth and elevation values are set as base azimuth and
base elevation values, at step 564. At step 566, a base histogram
of received packets and MCS levels is formed over a period of time
T (for the current/base azimuth value). At step 568, the
current/base azimuth value is dithered/adjusted by +0.1 beamwidth.
At step 570, a first adjusted histogram of received packets and MCS
levels is formed over the period of time T (for the adjusted
azimuth value from step 568).
[0079] At step 572, a determination is made regarding whether the
first adjusted histogram is approximately the same as the base
histogram. When the first adjusted histogram is not the same as the
base histogram, the adjusted azimuth value is set as the base
azimuth value (the elevation value set at step 564 remains the
same) and the steps 566-570 are repeated. At step 574, when the
first adjusted histogram is the same as the base histogram, the
base azimuth value is dithered by -0.1 beamwidth. At step 576, a
second adjusted histogram of received packets and MCS levels is
formed over the period of time T (for the adjusted azimuth value
from step 574).
[0080] At step 578, a determination is made regarding whether the
second adjusted histogram is approximately the same as the base
histogram. When the second adjusted histogram is not the same as
the base histogram, the adjusted azimuth value is set as the base
azimuth value at step 564, and steps 566-570 are repeated.
[0081] When the second adjusted histogram is the same as the base
histogram, the adjusted azimuth value is set as the base azimuth
value at step 580. At this point, adjustments to the azimuth value,
if needed, have been made while the elevation value remains the
same as the base elevation value set at step 564. At step 582, a
third adjusted histogram of received packets and MCS levels is
formed over the period of time T (for the azimuth and elevation
values from step 580). At step 584, the elevation value is
dithered/adjusted by +0.1 beamwidth. At step 586, a fourth adjusted
histogram of received packets and MCS levels is formed over the
period of time T (for the adjusted elevation value from step
584).
[0082] At step 588, a determination is made regarding whether the
fourth adjusted histogram is approximately the same as the base
histogram. When the fourth adjusted histogram is not the same as
the base histogram, the adjusted elevation value is set as the base
elevation value (the azimuth value set at step 580 remains the
same) and the steps 582-586 are repeated. At step 590, when the
fourth adjusted histogram is the same as the base histogram, the
elevation value is dithered by -0.1 beamwidth. At step 592, a fifth
adjusted histogram of received packets and MCS levels is formed
over the period of time T (for the adjusted elevation value from
step 590).
[0083] At step 594, a determination is made regarding whether the
fifth adjusted histogram is approximately the same as the base
histogram. When the fifth adjusted histogram is not the same as the
base histogram, the adjusted elevation value is set as the base
elevation value at step 580, and the steps following step 580 are
repeated. On the other hand, when the fifth adjusted histogram is
the same the base histogram, the adjusted elevation value is set as
the base elevation value at step 564, and the steps following step
564 are repeated. This is indicated by encircled reference B.
[0084] In some embodiments, the tracking operation 560 (including
adjustment of azimuth and elevation directions) is performed until
the aggregation node 102 is accurately tracked by the endpoint node
104. In other words, the various steps of the tracking operation
provide a tracked azimuth and tracked elevation value for the
endpoint node 104. In some embodiments, the controller 425 causes
the motor unit 322 to move the EHF module 320 according to the
tracked azimuth and elevation directions.
[0085] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
* * * * *