In space communications, traditional error correction/detection techniques deliver to the upper layers of the communication stack only the data units for which integrity can be guaranteed. The uncorrectable data units are then “lost”, and the upper layers have typically to face data units erasures. Hence, the packet erasure channel (PEC) is the most proper channel model from the point of view of the upper layers. Automatic repeat/retransmission query (ARQ) is the “traditional” solution implemented at the upper layers in order to face data units erasures. However, ARQ is not always possible for space or satellite communications. In such situations, forward error correction (FEC) must be used. Nowadays new techniques for FEC are available also for application at the upper layers. Long erasure correcting (LEC) codes represent a new and very promising proposal for packet erasure FEC. They are able to overcome the complexity limitations of other types of codes, while preserving very good erasure correction capability. They are currently under investigation within the CCSDS (Consultative Committee for Space Data Systems) long erasure codes Bird of Feather (LEC-BOF), where a leading role has been so far played by ESA/ESOC and NASA-JPL. In this paper, the activity of the LEC-BOF is be illustrated. More in detail, the basic ideas behind LEC codes are presented, as well as the possible codes structures, the encoding and decoding rules, some theoretical properties. Some numerical results are presented, showing the performance of LEC codes on both memory-less and burst erasure channel.
Long erasure correcting codes: the new frontier for zero loss in space applications?
PAOLINI, ENRICO;CHIANI, MARCO;
2006
Abstract
In space communications, traditional error correction/detection techniques deliver to the upper layers of the communication stack only the data units for which integrity can be guaranteed. The uncorrectable data units are then “lost”, and the upper layers have typically to face data units erasures. Hence, the packet erasure channel (PEC) is the most proper channel model from the point of view of the upper layers. Automatic repeat/retransmission query (ARQ) is the “traditional” solution implemented at the upper layers in order to face data units erasures. However, ARQ is not always possible for space or satellite communications. In such situations, forward error correction (FEC) must be used. Nowadays new techniques for FEC are available also for application at the upper layers. Long erasure correcting (LEC) codes represent a new and very promising proposal for packet erasure FEC. They are able to overcome the complexity limitations of other types of codes, while preserving very good erasure correction capability. They are currently under investigation within the CCSDS (Consultative Committee for Space Data Systems) long erasure codes Bird of Feather (LEC-BOF), where a leading role has been so far played by ESA/ESOC and NASA-JPL. In this paper, the activity of the LEC-BOF is be illustrated. More in detail, the basic ideas behind LEC codes are presented, as well as the possible codes structures, the encoding and decoding rules, some theoretical properties. Some numerical results are presented, showing the performance of LEC codes on both memory-less and burst erasure channel.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
