Filters

Settings

Now showing1 - 4 of 4
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Pulse shaping for satellite systems with time packing: An eigenfilter design
    (2015)
    Delamotte, Thomas
    ;
    Bauch, Gerhard
    Spectrum efficiency is becoming a major issue in satellite communications due to the dramatically increasing data rates requirements and the competition with terrestrial networks. The time packing strategy, by allowing to optimally exploit the available bandwidth without resorting to higher-order constellations, is a promising solution that has gained interest in the last years. The provided spectral efficiency improvement is obtained by accepting intersymbol interference (ISI) and the use of Nyquist pulse shaping filters is not required anymore for such systems. New filters, better complying with other design constraints can thus be considered. In this work, an eigenfilter design is proposed for the pulse shaping filters used in satellite systems with time packing. This design especially aim at limiting the envelope fluctuations of the transmit signals to offer better robustness against the distortions induced by highly nonlinear power amplifiers.
    Publicationtype: Conference Paper
      60
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Enhancing the LT component of raptor codes for inactivation decoding
    (2015-02)
    Lázaro Blasco, Francisco
    ;
    Liva, Gianluigi
    ;
    Bauch, Gerhard
    Based on recent results on the performance of LT codes under inactivation decoding, we show how to design the LT component of a Raptor code aiming at minimizing the decoding complexity under inactivation decoding. We provide a LT code design which has a lower decoding complexity compared to standardized Raptor codes while having exactly the same average encoding complexity and a similar probability of decoding failure. The proposed LT code would allow to increase the decoding throughput of raptor codes.
    Publicationtype: Conference Paper
      55
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Optimization of variable edge degree distributions to compensate the differential penalty by LDPC turbo decoding
    (2015)
    Pflüger, Doris
    ;
    Bauch, Gerhard
    Differential modulation is often applied in fiber optical communications in order to compensate for cycle slips. However, differential modulation causes a performance degradation compared to coherent detection, called the differential penalty. We consider a low density parity check (LDPC) coded system and include the differential modulation in the optimization of the LDPC code with the intention of overcoming the differential penalty. In this paper special attention is paid on the optimization of the variable edge degree distribution of the LDPC code. In this case the optimization problem is non linear. Therefore we derive substitute linear optimization problems that allow to determine upper and lower bounds of the maximal achievable rate. The corresponding degree distributions are determined explicitly. We explain why this method works well in the differential case but fails in the coherent case. In the differential case these new bounds allow to conclude for which parameters the differential penalty can be overcome. We show in particular that this is possible for high rates.
    Publicationtype: Conference Paper
      61
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Efficient maximum likelihood detection with imperfect channel state information for interference-limited MIMO systems
    (IEEE, 2015)
    Zhou, Guangxia
    ;
    Xu, Wen
    ;
    Bauch, Gerhard
    Advanced interference-aware detectors are being studied for 3GPP LTE-A to mitigate interference in multi-cell networks. In practical applications, imperfect channel estimates over noisy channels are inevitable. Ignoring them leads to severe performance degradation. The aim of this paper is to investigate a method for an interference-aware maximum likelihood detector to mitigate the impact of channel estimation errors. Simulation results for typical 3GPP LTE/LTE-A show the new method can provide flexibility and ability to deal with the channel estimation errors and to achieve a better trade-off between complexity (e.g., in terms of operations) and performance (e.g., in terms of error rate) in interference-limited scenarios. The proposed low-complexity CEN-ML sphere detector can have a gain of more than 5dB than the other investigated detectors for 16-QAM at a target coded block error rate of 0.01.
    Publicationtype: Conference Paper
      36