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The urban environment creates many unique
difficulties for modern military operations. Communications become
limited and unreliable due to multi-path reflections from walls, and
electromagnetic masking by thick concrete and steel structures. These
effects cause degradation in the Quality Of Service (QOS) for both
voice and data networks, even at very short ranges. In addition to
multi-path effects, multiple networks and large numbers of wireless
devices operating over a wide frequency spectrum and in a confined
area, cause severe interference. GPS coverage is often limited to open
areas, resulting in lack of coordination between forces and
insufficient situational awareness, especially for operations in
densely populated areas.
Furthermore, since urban guerillas are usually "non-uniformed,” and
often operate with non-combatants as human shields, hostile actions
can occur anywhere, from any direction, and without warning. Serious
incidents can develop due to mutual suspicion and poor communications,
causing loss of innocent lives. Controlling troops in such an
environment requires extraordinary command skills, and constant
situational awareness even for experienced combat leaders, and
especially at the junior tactical command levels, for operations
ranging from routine patrols and road-blocks to non-tactical movements
and supply convoys. Without reliable communications, though, even the
best leader will find that controlling urban operations is extremely
difficult
In support of urban operations, Command, Control, and Communications
(C3) can involve the use of many different systems, from satellite
links, wireless networks, and data-links to short-range, low power
communicators. Broadband wireless networks provide the framework for
net-enabled operations, allowing dissemination of a
Common Operations
Picture (COP) among all participating forces. Combat Net Radio (CNR)
sets, now increasingly integrated into current combat vehicles,
already support integrated voice and data communications, facilitating
direct links to databases and automatic reporting to battalion,
brigade and division levels.
Maintaining effective Command and Control in urban combat requires the
use of efficient and effective networks supporting all combatants
throughout the area, regardless of their location. These capabilities
are not easily provided because electromagnetic propagation is
severely degraded in such cluttered terrain, frequently limiting
communications to short range, or even line of sight. Communications
between neighboring forces, sometimes even on parallel roads, can be
limited and sporadically scattered. Significant improvement in
coverage can be gained by operating relay stations from airborne
platforms or on high ground. Maturing aerostat technology, including
miniature, man-portable systems, has established these simple and
reliable platforms as effective providers of communications relay
services. An aerostat is more reliable than a UAV, especially under
adverse weather conditions when a UAV cannot operate. Anchored to the
ground, an aerostat maintains its position for long periods without
requiring human control or support.
Ground combat communications networks are usually operated in the VHF
frequency band. This frequency band is relatively narrow and military
radio networks do not use the available bandwidth as efficiently as
current commercial systems. Consequent lack of available frequencies
can limit the use of radio relays to overcome masking and
interference.
One solution to the problem is the use of Commercial Off The Shelf
(COTS) based communications systems. Unlike legacy military radios or
even the newer frequency hoppers which require dedicated frequency
resources for each network, COTS systems dynamically share a wide
frequency band for optimal use of scarce resources. Employing the
TETRA,
TETRAPOL, or APCO-25 commercial standards, COTS systems are
designed to provide deployable, reliable, and secure communications
even under peak loads.
Mobile subscriber networks, such as the TETRA based emergency
communications network fielded by Motorola Communications, provide
automatic relaying of communications and data. Emergency
communications networks utilize ad-hoc communications to establish
bypasses between two points when direct communications are not
possible. The network automatically establishes paths through other
elements to regain the flow of information between all points and the
central command post.
Modern military networks are following a similar pattern. These
include relatively simple wireless networks utilizing
"wi-fi"
protocols, as well as advanced mesh networks, which utilize advanced
methods designed specifically to cope with the adverse effects of
urban terrain. Operating multiple high capacity links supporting video
transmissions and control of remote systems requires the fielding of
special data-links. Relying on industry standards, such as the
commercial COFDM protocol, which was originally developed to support
mass distribution of digital broadcasts; modern data-links are
designed to deliver compressed video and command signals with very low
latency and high quality.
At the lower tactical level, Personal Role Radio communicators (PRR)
are used to link squad members. Only Special Operations forces
previously used this type of communication system. The use of such
communicators enables more effective control of all personnel due to
constant reporting and tracking of troops and automatic transmission
of emergency calls (by pressing the "panic button"). These devices
enable the flow of information to and from the dismounted unit without
dependence on a vehicular platform for Command and Control. PRRs can
interface with weapon sights, hand held computers, and navigation
equipment to form an integrated combat suite for the warfighter. While
PRRs are very effective when operations are conducted in open areas,
their coverage and range degrades dramatically in confined spaces.
Most systems can only work through one or two floors or walls,
therefore limiting communications when operating inside buildings, or
subterranean passages.
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