Broadband VHF Aeronautical Communications System Based on MC-CDMA

Background

Air/ground communications are critical for achieving an ATM system that is capable of meeting air traffic demands in the future. Today’s narrowband VHF technologies are using the VHF spectrum allocated for aeronautical safety communications in a highly inefficient manner. Spectrum efficiency could be improved by using broadband communications. The B-VHF project will investigate the feasibility of broadband multi-carrier (MC) technology combined with CDMA (Code Division Multiple Access) for VHF aeronautical communications.

Project objectives

The high-level goal of the B-VHF project is to prove the feasibility of the broadband MC-CDMA technology and demonstrate the benefits of this technology to the aeronautical community.

Additionally, the project will demonstrate that the B-VHF system has the capability to support an increased number of users within the same VHF spectrum while providing higher aggregate channel throughput than the sum of legacy systems occupying the same spectrum.

MC-CDMA technology can be easily adapted to various user needs and usage scenarios, providing various types of communications services to users’ applications with different service attributes and quality of service expectations.

The preferred B-VHF deployment concept anticipates that the new system would be initially operated in parallel with the legacy narrowband VHF systems in a given area (overlay concept), virtually using the same part of the VHF spectrum without inter-system interference and without requiring additional spectral resources.

The following two figures depict the current situation in the VHF COM band and the resulting VHF band occupancy, reflecting the co-existence of the B-VHF system with the legacy VHF systems.

Description of the work

Th tasks required to achieve these objectives are encapsulated into four separate Work Packages:

Work Package 0 Project Management and Quality Assurance: comprises activities that are essential to all Work Packages. It covers all management activities within the consortium and in particular the liaison with the European Commission.

Work Package 1 B-VHF System Aspects: produces high-level requirements for the B-VHF system, describes the reference aeronautical environment used in simulations of the B-VHF system, as well as the B-VHF Operational Concept. Work Package 1 will be closed after producing the B-VHF Deployment Scenario document. It will address technological, operational and institutional issues of the B-VHF initial deployment, transition and operational usage.

Work Package 2 VHF Band Compatibility Aspects: addresses the theoretical and practical assessment of probably the most critical aspect of the future B-VHF broadband system: its capability to be installed and operated, ‘interweaved’ with a number of legacy narrowband systems, sharing the same part of the VHF spectrum, but remaining robust against interference coming from such legacy narrowband VHF systems.

Work Package 3 B-VHF Design and Evaluation: covers B-VHF system detailed design tasks, starting with developing the model of the broadband VHF channel and proceeding with the development of the software representing the physical B-VHF layer, DLL (Dynamic Link Library) layer, higher protocol layers and representative aeronautical applications for the subsequent performance simulations.

Work Package 4 B-VHF Test bed: covers the base band implementation and evaluation of a test bed for both the forward and reverse B-VHF link. The implementation is restricted to the physical layer, which is the most critical part in the B-VHF system.

Expected results

The B-VHF system is expected to provide additional communications capacity by re-using the existing VHF COM spectrum, but without interference from legacy narrowband systems. The transition aspects shall be substantially easier than for any other known alternative. Spectrally efficient broadband B-VHF technology will provide capacity and performance for today’s and future operational services and remove today’s argument that the aeronautical spectrum is used in a very inefficient way.

The following two figures depict the current situation in the VHF COM band and the resulting VHF band occupancy, reflecting the co-existence of the B-VHF system with the legacy VHF systems.