SIMULATIONS
PSI defines
a simulation as one or more tasks
running on a computer, typically taking in files, interactive inputs, and
real-time channel feeds. Simulations
produce graphical or literal data outputs to interactive screens, files or
real-time channels. Using GSS,
simulations can be run multiple times automatically for parametric or
sensitivity analysis, or under the GSS optimization facility. Models
are built to represent entities that are incorporated into a simulation. Models must contain sufficient detail so
that, when a simulation is run, the measures of performance or effectiveness
produced are sufficiently accurate to meet validity requirements on the
results.
Listed below is a sampling of simulations that PSI has provided to clients over the past fifteen years. Since most of PSI's clients are engaged in communications technology, this list is somewhat limited to communications simulations. Prior to this listing is a description of network connectivity simulations and capacity simulations. Simulations built over the past five years contain combined connectivity and capacity models working together. As simulations get large, or when simulations are required to play with other simulations, then users can use the GSS distributed simulation environment to run multiple simulations over a network of distributed platforms.
NETWORK CONNECTIVITY
SIMULATIONS
Network
connectivity can be determined for wired and wireless transmission systems
based on models for backbone and access nodes as well as individual mobile
subscribers. This covers multichannel
links including antennas, interference, mobile telephones and their dynamic
movement on rough terrain and in foliage.
These simulations can be used to assess the connectivity of a complete network. This provides for simulation of a large
nodal system with highly directional antennas and multiple dynamic interference
sources to allow detailed analysis of network connectivity, vulnerability, and
susceptibility. Nodes can be on
helicopters, fast moving aircraft, and satellites with orbital equations
describing the motion and position at intervals specified by the user so that
changing connectivity can be used to assess adaptive network management
algorithms dynamically.
NETWORK CAPACITY
SIMULATIONS
Network
capacity can be determined at all levels of resolution by simulations based on
GSS models for backbone and access nodes, aggregated subscriber facilities,
detailed voice subscribers, and client-host data system traffic. These simulations are designed to
incorporate specific instrumentation models to analyze the capacity of an
active network under realistic stress conditions including dynamic link error
rates generated from the connectivity models, and equipment downtime. Detailed models of all protocol layers and
routing algorithms are also incorporated in these models. These include adaptive algorithms for
flooding, contention access, TDMA, CDMA, FDMA, as well as other standard
routing methods.
COMBINED SIMULATIONS
As
requirements for simulations grow, and multiple equipments and systems must be
represented to provide more realistic overall assessments of complex scenarios,
it becomes necessary to bring models of many systems together into a single
simulation. These systems can represent
intelligence systems, EW systems, weapon systems, logistic systems, and command
and control systems, as well as the combination of connectivity and
capacity. GSS has prevailed as the
ideal framework for these large scale simulations, with models at varying
resolutions and large numbers of moving platforms to insure validity of
results.
DISTRIBUTED
SIMULATIONS
As the need
for combined simulations grow, the interaction of multiple simulations running
together becomes a desired solution approach.
This allows the area experts to focus on the problem they are trained to
solve, as long as the inputs from sources that feed their environment are
included. Most often, the interaction
between these different systems affects the outcome of one or both, and must be
accounted for as the scenario unfolds.
Data coherency and time synchronization become the problems to solve,
and these are automatically solved with GSS.