SLS-CS_12-05 Some results on NGU coding schemes SLS-CS_12-05 UnivPM-UniBO_NGU_Input.v2 SLS-CS_12-05 Some results on NGU coding schemes Marco Baldi1, Marco Chiani2, Franco Chiaraluce1, Enrico Paolini2 1 Università Politecnica delle Marche, Ancona, Italy {m.baldi, f.chiaraluce}@univpm.it 2 Università di Bologna, Bologna, Italy {marco.chiani, e.paolini}@unibo.it

(128, 64) NASA binary LDPC code

Max Iterations vs Performance

Comparison with non-binary codes

(256, 128) NASA binary LDPC code

Max Iterations vs Performance

Comparison with non-binary codes

(512, 256) NASA binary LDPC code

Max Iterations vs Performance

Binary VS non-binary codes Short non-binary LDPC codes outperform their binary counterparts by 1 dB or more This appears to be independent of the maximum number of iterations allowed for decoding a received frame The convergence speed (in terms of used iterations) of binary and non-binary codes is comparable The parity-check matrices of the non-binary codes which have been used as a reference are the same used in: L. Costantini, B. Matuz, G. Liva, E. Paolini, M. Chiani, «Non-binary protograph low-density parity-check codes for space communications,» Int. J. of Satellite Communications and Networking, Vol. 30, No. 2, pp. 43–51, 2012

Comments on TC Randomization It has already been observed [Alvarez2006] that, when used at high data-rates, the CCSDS standard TM randomizer incurs spurious problems The problem is mainly due to Only Idle Data (OID) Frames, which are typically filled by zero bits before randomization Depending on the mission requirements, some solutions have been studied to ensure suitable randomization of high rate data [Garello2009] [Alvarez2006] O. Alvarez and G. Lesthievent, “Pseudo-Random Codes for High Data Rate Telemetry: Analysis and New Proposal”, presented at CCSDS RF & Modulation & Channel Coding Working Groups, Rome, Italy, 12 June 2006. [Garello2009] R. Garello, M. Baldi, F. Chiaraluce, “Randomizer for High Data Rates”, European Space Agency Contract Report, March 2009, ESOC Contract No. 20959/07/D/MRP.

Comments on TC Randomization (2) At the Earth's surface, the power flux density (PFD) produced by spacecraft emissions must not exceed prefixed values, fixed by ITU and ECSS These limits are those of interest for high data rate TM links Concerning NGU links, transmission occurs from Earth to a spacecraft, or between two spacecrafts What are the requirements to be considered for spurious frequencies (PFD masks, synchronization issues…)? Idle frames in asynchronous uplink services?