B-VHF 'fills' the spectrum gaps Broadband VHF
Air transport has been identified as a dominant factor for sustainable economic growth of the European Union. The "Vision 2020" clearly points out the cornerstones of a future air transport system as recommended by the Advisory Council for ATM Research in Europe (ACARE). Hereby the A/G communication will be a key element and meet the need of alternative communications systems indicated by the Eurocontrol’s Communications Strategy. The B-VHF project aims at identifying MC-CDMA as the still missing European approach for the future ATM VHF communication system that supports Single European Sky and the Free Flight concept.
The main objectives of the project are to proof
Thereby, it will be demonstrated that, compared to legacy solutions, the B-VHF system has the capability to support an increased number of users within the same VHF spectrum and also provides higher aggregate channel throughput than the sum of legacy systems occupying the same spectrum.
Technical Approach
The target transmission technique for a future broadband VHF link is called Multi-Carrier Code Division Multiple Access (MC-CDMA) that in turn is based on Orthogonal Frequency Division Multiplexing (OFDM). OFDM uses not just one single carrier to transmit a signal of desired bandwidth B, but several individual so-called subcarriers. These subcarriers are orthogonal to each other and therefore cause no IntersubCarrier Interference (ICI).
MC-CDMA is a technique that is applied on top of OFDM. In the standard OFDM system it can happen that one subcarrier is completely faded and the transmitted information in this sub-carrier cannot be reconstructed in the receiver. In an MC-CDMA system the information is spread over several subcarriers. Even if one of the subcarriers in a spreading group is faded, it is in the most cases possible to recover the transmitted information.
Dedicated subcarriers in the MC-CDMA spectrum (e.g. known carriers of legacy narrowband systems) can be left unoccupied. This opens the possibility to run the MC-CDMA system in parallel with the current narrowband systems. The MC-CDMA sub-carriers would just fill the gaps between the narrowband carriers, providing additional communications capacity within the part of existing VHF COM spectrum without interfering with legacy narrowband systems.
funded by
The 6. EU's Framework Programme for Research and Development
Project Website
http://www.b-vhf.org
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