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    Wideband channel modeling for wireless avionics intra-communications
    (2025)
    Brüggmann, Jasper
    ;
    Reyes Torres, Oscar Mauricio
    ;
    Bauch, Gerhard
    ;
    Schappmann, Christian
    Wireless Avionics Intra-Communications (WAIC) has been proposed to partially replace costly wiring in future generations of aircraft. Besides the allocation of a frequency range and several performance figures, there is no standardized transmission scheme so far. For the design of suitable physical layer techniques, comprehensive models are required to perform realistic link-level simulations for the aircraft environment. We present a wideband channel model for in-cabin WAIC systems, that has been derived from channel measurements performed in an Airbus A321 cabin. The model is validated by comparing physically measured frame error rates to simulated error ratesusing the proposed model in an OFDM transmission based on IEEE 802.11a applied to the WAIC frequency band.
    Publicationtype: Conference Poster not in Proceedings
      51  38
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    Item type:Publication, Access status: with files ,
    On neural network data predistortion and constellation shaping for satellite channels
    (2025)
    Kopyto, David Jonas
    ;
    Bauch, Gerhard
    In communication over transparent satellite payloads, traveling wave-tube amplifier (TWTA) cause nonlinear distortion to the transmit signal. Together with filters involved in the transmission chain, the TWTA causes distorted decision regions (warping) and intersymbol interference (ISI) at the matched filter output. This nonlinear channel can be compensated by means of data predistortion. The remaining interference results can be interpreted as a channel and the transmit constellation can be optimized for the joint channel with influences from additive white Gaussian noise (AWGN) and phase noise. This work shows how constellation shaping and data predistortion can be designed using neural networks. Particularly, a novel data predistortion algorithm based on a recurrent neural network (RNN) which accounts for the ISI is presented. For constellation shaping, different constrained optimization techniques are presented, including quadrant-symmetric optimization, spiral constellations and amplitude and phase-shift keying (APSK) constellations. All constellations are shaped by implementing the communication chain as an autoencoder, which is trained on a channel with the abovementioned impairments, which occur in satellite links. Resulting constellations are presented together with data predistortion, bit error rate (BER) and information rates.
    Publicationtype: Conference Poster not in Proceedings
      36  27