International airline passenger travel increased by 7.4% over the last year, largely supported by significant economical growth in China (http://www2.bombardier.com This number reflects how today’s worldwide economy grows more and more connected, with airline travel being a perfect representation of global inter-dependence. It drives competition, forcing airlines to reduce their costs of operation. Raising oil prices have also been a major challenge. Airlines are looking at ways to reduce their expenses by focusing on fuel-efficient solutions. Fuel-efficiency also has a positive impact on the environmental footprint of airplanes, hence the recent push for ‘Green Airplanes’ innovations. The AVIO-505 project from the Consortium for Research and Innovation in Aerospace in Québec (CRIAQ) is a perfect example on how industry and universities can partner together to address challenging problems.

Overview of avionics technologies to be implemented in SDR

Focusing on wireless communication and positioning equipment, the CRIAQ’s AVIO-505 project leverages Software-Defined Radio (SDR) technology to create a highly integrated and reconfigurable solution for aircraft manufacturers. The initial goal is to integrate four main avionic technologies:

 DME (Distance Measuring Equipment)
 Mode S Transponder
 ADS-B (Automatic Dependent Surveillance – Broadcast)
 WBR (Wide Band Radio)

Avionics protocols such as DME, Mode S, and ADS-B are narrowband protocols, mostly serving for identification and location, and carry very little information. On the other hand, WBR carries much more information (50 MHz bandwidth or more) and requires very stringent hardware characteristics. The overall effect on plane weight from each system is quite significant, hence the benefit of an integrated SDR approach.

The advantages of SDR in avionics

With SDR technology, a single piece of avionics hardware can function as DME, Mode S, ADS-B, or WBR. The WBR function could be shut down during takeoff to ensure a focus on location and identification, whereas DME, Mode S, and ADS-B functions could be enabled temporarily depending on the context of the flight. For example, if the plane goes over an ocean, DME and could be disabled as it is an air-ground protocol. Adopting an SDR approach for avionics will not only reduce plane weight. It will also:

 Reduce the number of coax cables and antennas
 Reduce the overall number of parts, which means improved reliability and a globally safer system
 Reduce the power consumption by eliminating ‘idle’ state equipment
 Reduce the integration time required to develop new equipment

The challenges of implementing SDR on airplanes

Although the main challenge of this SDR project consists of implementing the avionic functional modules purely in software, it is important to keep in mind that it is the integrated value of the system that matters most. As with any SDR project, all the individual components already exist commercially. This means that nay resulting system will have to undergo strict certification tests such as RTCA DO 160 (Environmental Conditions and Test Procedures for Airborne Equipment (http:/ The mechanical integration to the overall airplane equipment is also an important challenge. For example, the antenna required by an SDR system must be limited in size if it is to be integrated on smaller airplanes. For larger airplanes (500 passengers or more), which have enough space, the challenge is to ensure that the total bandwidth required by the WBR equipment can sustain internet access for each passenger.


We have seen that applying the SDR concept to the aerospace industry holds great promises and is likely to become a key technology for sustaining growth. As is often the case, the challenges behind this project reflect the level of benefits brought on by this innovative approach. For this application, the CRIAQ provides a perfect context for development, as it brings on board companies and university experts with various expertise, all aiming at finding a workable solution. Nutaq is proud to be part of CRIAQ AVIO-505 project ‘Software Defined Radio for Highly Integrated System Architecture’.