The JTRS Program: Software-Defined Radios as a Software Product Line
Eric Koski and Charles Linn
Harris Corporation, RF Communications Division
Eric.Koski@harris.com, Charles.Linn@harris.com
Abstract
The Joint Tactical Radio System (JTRS) program of
the US Department of Defense is an ambitious multi-
year initiative aimed at developing a new family of
highly capable software programmable radio systems
designed around a common Software Communications
Architecture (SCA). The procurement and
development approaches of the JTRS initiative make it
an interesting application of a software product line
strategy. In this paper, we
Provide an overview of the JTRS program, its key
technologies, and its development and procurement
strategies
Highlight the aspects of the JTRS program that
make it a clear instance of a software product line
Analyze the degrees of success with which product
line concepts have been applied within the JTRS
initiative, and highlight some ongoing challenges
Discuss the significance of the JTRS initiative for
the Software Product Lines community.
1. Introduction
The Joint Tactical Radio System (JTRS) program of
the US Department of Defense is an ambitious multi-
year initiative aimed at developing a new family of
highly capable software programmable radio systems
designed around a common Software Communications
Architecture (SCA). JTRS radios are envisioned to be
highly modular, scaleable, upgradeable, network-
capable, and interoperable with existing ‘legacy’ radio
systems. Use of the common SCA-defined architecture
is intended to ensure that waveforms can be easily
ported from one radio type to another, radios of
multiple types are fully interoperable, and common
software can be effectively reused from one radio type
to another. JTRS radio systems are being procured in
four ‘cluster’ procurements with a combined potential
value of multiple billions of dollars, with additional
procurements forthcoming. (Defined JTRS Program
funding was $5.9 billion as of August 2003 [16]. Total
procurement cost has been estimated at $15.6 billion
for JTRS Cluster 1 and $8.7 billion for JTRS Cluster 5
[17].) The radio types being procured span a
continuum from large multi-channel shipboard and
airborne radio systems to ‘Small Form Fit’ (SFF)
radios for embedding into sensors and smart munitions.
The procurement and development approaches of
the JTRS initiative make it an interesting application of
a software product line strategy. An unprecedented
feature of the JTRS initiative is that it applies such a
strategy to almost an entire industry, spanning a large
number of individual corporate suppliers.
2. JTRS background
The JTRS mission is to procure an entire new
generation of software programmable radios designed
around a common, open software architecture, and
replacing all US military radio systems operating from
2 MHz to 2 GHz (and beyond). Over past years, the
individual military services have amassed a collection
of over 25 to 30 types of radio systems, operating 40
different communications waveforms across a range of
frequency bands. Each platform was manufacturer
proprietary, and users often experienced
interoperability problems between radios from different
vendors. As newer, network-centric waveforms
became needed to fulfill the seamless networking goals
of Joint Vision 2020 [11], the US military was faced
with the prospect of multiple, parallel procurements
from multiple platform vendors. Furthermore, none of
the existing radio platforms were suited in hardware or
processing capability to implement these new
waveforms. When logistical support was also
considered (something that easily exceeds the cost of
the platforms themselves), it became clear that
deploying new waveforms onto these multiple
platforms would be prohibitively expensive.
To succeed required a different approach,
involving the development and validation of a new,
standardized architecture, and acquisition of a new
family of radios together with a set of communications
waveforms to run on those radios. This approach
required the formal separation of the platform hardware
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