L-DACS1 physical layer laboratory demonstrator

Abstract

In this paper, an L-DACS1 physical layer laboratory demonstrator is presented which has been implemented recently in FPGA technology by the German Aerospace Center (DLR). The main goal of this lab demonstrator is to perform first compatibility measurements between L-DACS1 and legacy L-band systems where interference from L-DACS1 towards the legacy systems as well as interference from the legacy systems onto the L-DACS1 receiver is considered. The lab demonstrator is already implemented up to the first intermediate frequency at 10.7 MHz. The radio frontend for up-/down-conversion to/from the Lband is scheduled to be delivered in May this year. First compatibility tests are planned to take place in the labs of the German ATC authority DFS this summer. Using real hardware equipment, these tests will give valuable insight into the L-band coexistence issue and possible deployment scenarios.

L-DACS1 laboratory demonstrator development and compatibility measurement set-up

“…In the following, the measurement results for the transmitter spectral mask and the overall transmission chain for the IF loop are reported as already presented in [2]. In addition, preliminary results obtained for the RF loop are presented based on the experimental RF frontend set-up.…”

“…Both the transmitter and receiver implementation is described in detail in [2] and summarized in the following two subsections.…”

“…The generated signals have to be sent back to the AVST interface firmware, which for the Tx has to be configured to transmit data to the D/A board. To accomplish these tasks, functional blocks are connected via AVST into a processing chain [2]. As a consequence, arbitrary sequences of L-DACS1 frames -FL and RL -can be realized by this transmitter implementation.…”

“…The demonstrator is implemented in FPGA technology [2] and comprises a complete implementation of the physical layer of the L-DACS1 transmitter, including adaptive coding and modulation as well as the complete framing structure for forward and reverse link. The receiver of the L-DACS1 demonstrator is implemented only partly in hardware.…”

OFDM based data link for the DLR research aircraft ATRA

“…The system is partly based on the L-DACS1 demonstrator developed by the DLR [5]. The section starts with an overview of the demonstrator's hardware and software components.…”