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Focus: Toward SDR Standardization
by Carlo Zammeriello, EDA Software Defined Radio Principal Officer, and Andrea Lorelli, ETSI TC RRS Technical Officer

Software Defined Radio (SDR) is a well-established concept in the military domain where the radio is no longer the physical manufacturing of a single waveform but becomes a computer host onto which different waveforms can be loaded. The military have been studying SDR for a long time and has adopted the Software Communication Architecture (SCA) as the “de-facto” standard upon which different solutions can be developed.

SDRGrph1 SCA is published by the Joint Program Executive Office (JPEO, under the umbrella of the US Department of Defence - DoD) of the Joint Tactical Radio System (JTRS). This architecture has been developed to assist in the development of SDR communication systems and captures the benefits of most recent technology advances to greatly enhance the interoperability of communication systems and reduce development and deployment costs. Together with the SCA architecture (v 2.2.2 now evolving to the so-called “SCA Next”), the JPEO has also published a number of APIs (Application Programming Interfaces), to allow software components to communicate with each other, but some have a restricted access (basically security and crypto APIs).

On this side of the ocean two programs are currently working on the same topic.

ESSOR (European Secure Software Radio Program) is a program realized as a joint effort between six nations: Finland, France, Italy, Poland, Spain and Sweden and managed by OCCAR (Organization for Joint Armament Cooperation). ESSOR is based on the (public) SCA architecture (SCA 2.2.2 and JTRS 1.0.3 APIs) and aims at developing an architecture of Software Defined Radio (SDR) for military purposes and a military High Data Rate Waveform (HDR WF) compliant with such an architecture.

SVFuA is the German national program aiming at developing an architecture of SDR to be used by the Bundeswehr, the German Federal Armed Forces. Also, in this case the starting point is the public SCA architecture (SCA 2.2.2 and JTRS 1.0.3 APIs). With respect to the ESSOR program, Germany doesn’t currently have any national military High Data Rate Waveform (HDR WF) initiatives, but rely on another program, COALWNW (Coalition Wideband Networking Waveform), to satisfy their operational requirements.

sdrFig1 The COALWNW objective is to realize a wideband, networking High Data Rate Waveform (similar to the one under development in ESSOR) to pass secure voice, video, and data among Coalition Partners. Partners of this program are: the United States, the United Kingdom, France, Italy, Germany, Australia, Sweden, Finland and Spain.

The coexistence of a U.S. program (JTRS) and two European programs (ESSOR and SVFuA) for the SCA-based SDR architecture plus one transatlantic program for an HDR waveform translates into two risks that need to be managed: duplication of effort; and the loss of interoperability, both at the European level and transatlantic level.

Software Defined Radio is a key issue in the European Defence Agency’s agenda as it is seen as a means to maximize interoperability amongst coalition forces. The approach favored by EDA is to push for an “international SDR standard”. In November 2009, with the help of the Finnish armed forces, the EDA organized a conference in Helsinki to address this topic.

sdrFig2 The conference brought together international key stake-holders and speakers from EDA, ESSOR, U.S. JPEO, NATO, the European Telecommunications Standards Institute (ETSI) and the Wireless Innovations Forum (WINNF).

The main achievements of the conference was the initial consensus on the principle to approach standardization with what was then known as the “three basket model” and that ETSI, together with the Wireless Innovation Forum, were possible candidates for the custodianship of some international SDR standards. All this, then, depended on final agreements with the involved governmental stakeholders. The model sees SDR architecture standardization falling into three different baskets.

The first basket is related to market driven technologies that are available to everyone, where the Governmental Stakeholder Group, i.e., contributing nations, would control the content and release of defence related product specifications in order to guarantee compatibility with non-public API specifications as well as backward compatibility.

The second basket includes more sensitive issues, such as security and crypto APIs, where the governments, as trusted partners, would remain in charge of custodianship.

sdrFig3 There may also be need for a third basket which deals specifically with Nation sensitive information.

Since the first time the three basket model was presented, many discussions were started on how to make it happen. One point of common agreement is that it would be beneficial for the military SDR community to transfer control of the standardization activities to a Standard Developing Organization (SDO), at least for that part of the standard not containing sensitive information (and so not restricted). Some advantages of such an approach would be the following:

• Avoiding duplication of work and divergences, which could hamper interoperability
• The reduction of costs
• The fostering of harmonization and help with speeding up the convergence process

During the workshop on SDR and Cognitive Radio (CR) standardization that took place on the November 17 and 18, 2011, in Ispra (organized by the Joint Research Centre—JRC—and co-hosted by the Directorate General Enterprise and Industry—DG ENTR—and EDA), ETSI, in cooperation with the EDA and the JRC, presented a model aiming at reaching a European standard in the short/medium term and a converged standard allowing transatlantic interoperability in the mid/long term (i.e., between Europe and the U.S.), which is of paramount importance for joint operations. It is important to remark that this mode, as of this writing,

xicomtech_ad_MSM0312 Has not been endorsed yet by EU stakeholders, but all are showing great interest
Is perfectly aligned with the objectives of the EU government standardization strategies (mainly ESSOR);

Foresees since the beginning, the presence of both WINNF and the U.S. government and industries (if available to participate).

Is also aligned with the three basket model as it involves an officially recognized European Standard Organization (ETSI) for all those standardization activities not requiring any restriction, which corresponds to basket one of the three basket model.

The ETSI-EDA Model
The model is based on the assumption that, while a “transatlantic” SDR standard for a military application is certainly the ultimate aim, in the short term at least, a U.S. program and a European program will continue to exist separately. This is also due to the fact the U.S. program is more advanced than the European ones (ESSOR and SFVuA) and, therefore, a convergence and harmonization can best take place in the medium/long term.

The model takes into account these considerations and allows for a seamless transition within the same standardization body from “regional standards” to an “international standard” without hampering, in the short term, the developments of existing programs. It is assumed here that the European standardization activities will take place in a dedicated Working Group (WG5) of the Technical Committee Reconfigurable Radio System (TC RRS).

TC RRS is responsible within ETSI for SDR and CR standardization and, therefore, is the natural host for SDR standardization for military applications. Two options are possible...

• In the first case, TC RRS will host the standardization activities related to a European standard
• In the second case, an ideal model is drawn where the two short-term regional standards are developed in the same committee,
i.e., ETSI TC RRS. In both cases interoperability, i.e., a converged standard for joint operations, is considered essential for the mid/long term achievement

The Model For The EC Standard
The starting point is the ongoing regional European programs, i.e., ESSOR and SVFuA. A set of interoperability specifications (to be developed in cooperation with the U.S.) would speed up the “migration” towards a converged standard, which is supposed to take place in the medium/long term.

The WINNF, with its technical expertise in SCA, could provide support to the standard development and help coordinate the technical and market requirements with respect to the U.S. program. This will assure a gradual convergence towards the “international standard”, which remains the final target for the mid/long term. The Interoperability Specifications produced are therefore expected to provide the baselines for such a convergence.

The Model For The Converged Standard
The following section describes the model for achieving an international standard in the mid/long term. Although ETSI has had preliminary discussions with the U.S. on this topic and a positive feedback has been received, the final model to be applied has not yet been agreed.

As shown in Figure 2, in the short term it is envisaged to have two different regional standards as well as a set of interoperability specifications for instance, under the form of ETSI Technical Specifications and/or feasibility studies (ETSI Technical Reports) that would “complement” the regional standard themselves. It is assumed that the starting points are the ongoing regional programs, i.e.:

• ESSOR/SVFuA for the “regional standard 1”, i.e. for the European Standard
• JTRS specification for the “regional standard 2”,
i.e. for the U.S. Standard

The set of inter-operability specifications complementing the regional standards would speed up the “migration” towards a converged standard, which is supposed to take place in the medium/long term.

The two regional standards would be developed independently of each other in the same committee without forgetting the interoperability element which is essential for the development of a single standard in the mid/long term. In this regard, it is clearly an advantage to have all these activities within the same committee as it will optimize resources (some stakeholders might be interested in participating actively in the development of both regional standards).

At the same time, the WINNF, with its technical expertise in SCA, would provide support to the standard development and would help in the coordination of technical and market requirements. In Figure 2, it is assumed that these activities will take place in a single Working Group (WG5) but it would be also possible to create two separate Working Groups for the two regional standards (WG5 and WG6). In this case, the two working groups are supposed to coordinate their activities in order to minimize the duplication of work and maximize interoperability in the short term. The model is shown in Figure 3.

This article has presented the EDA-ETSI model for starting military SDR standardization in the most efficient way. ETSI is an officially recognized European Standard Organization (ESO) and a Global Standard Producer (GSP) and can thus offer a single “forum” where standardization activities can start and evolve in the medium/long term towards a true transatlantic and globally recognized standard.