AC Summer 08 WIN-T Online - United States Army Signal Center of ...

Initial NCW Radio
Implementation (MPM-1000
modem plus two different OTM
antennas, one for POP and TCN
and one for SNE).
platforms as well, maximizing
frequency reuse for this tier. This
frequency reuse is automated, with
no user involvement required and is
dynamic to support OTM operation.
c. Demand Assigned User
Data. The HNW assigns timeslots
based on user demand. More
timeslots for that link are assigned
when demand increases at a specific
node. When demand decreases at a
specific node, less timeslots are used
for that link, leaving these timeslots
to be used by other nodes. This
demand assignment feature allows
bandwidth sharing across the
network, optimizes network
throughput, and minimizes spectrum
required.
d. Variable Bandwidths.
HNW networks can be set up in
scarce spectrum environments. It
includes selectable channel bandwidths
of 3.125, 6.25, 12.5, 25 and 50
MHz. This allows connectivity and
throughput for an entire tactical
deployment even with limited
spectrum availability.
e. Self-forming and Selfhealing
Network. The HNW
supports mobile ad hoc networking
by automatically discovering and
tracking moving nodes. The HNW
differs from many ad hoc networking
waveforms in that it is designed
to operate with an antenna that
supports narrow beam directional
functionality. To support this form
of ad hoc networking, the HNW
includes a Time Division Duplex
TDMA protocol that schedules
access to the communications
channel. The TDD TDMA not only
controls the time at which a link
between nodes has access to the
communications channel, but also
controls the direction over which
that link operates. This allows mesh
connectivity to many other nodes
simultaneously and supports a
robust network. A robust network
allows user bits to travel to the
intended network location using the
least number of links. This minimizes
spectrum use.
SATCOM waveform
The Network-Centric Waveform
provides OTM and ATH
satellite communications between
users in a full-mesh multi-frequency
time-division multiple access
network. The NCW SATCOM link
provides range extension for the
WIN-T WAN backbone network
through the use of various
MILSATCOM and commercial
transponded satellites. The WIN-T
NCW network leverages C/X/Ku/
Ka bands ATH and Ku/Ka bands
on-the-move. NCW includes
integrated transmission security that
covers both signaling and user
traffic.
NCW uses a network scheduler.
This automatically calculates
optimum connectivity between all
network member terminals in a
mixed network supporting both
OTM and ATH communications.
NCW supports mesh connectivity
between users while OTM, and does
not require a large aperture hub for
operation. Any terminal can act as
network controller, and devolution
to alternate controllers is automatic.
NCW includes very powerful,
dynamic features to maximize
satellite transponder resources. The
features contributing to the efficiency
of NCW are described below.
a. Dynamic Throughput.
Member terminals measure performance
in real time and provide this
measure back to the network controller.
This information is used to
determine the modulation and
coding mode the terminal will use.
This provides automated dynamic
throughput adjustment based on
link conditions, allowing the use of
the available link margin to support
additional throughput. This means
that the link continues to work at
reduced throughput when traditional
satellite communications links
would break.
b. Demand Assigned. The
TDMA structure of the waveform is
used to assign timeslots to terminals.
Only a limited number of timeslots
are assigned to a specific terminal,
when little or no throughput is
required. This leaves timeslots
available for other terminals.
When additional throughput is
required, additional timeslots are
assigned. This allows for the sharing
of transponder resources across the
network, which optimizes throughput
and minimizes the number of
satellite transponders that are
required for a given deployment.
Scheduled virtual connections also
provide data to the intended node,
minimizing double hops experienced
in legacy networks and
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