Rate Adaptation for Incremental Redundancy Secure HARQ

Zeina Mheich (1) , Maël Le Treust (2) , Florence Alberge (1) , Pierre Duhamel (1)

1 L2S - Laboratoire des signaux et systèmes
2 ICI

This paper studies secure communication based on incremental redundancy (INR) secure hybrid automatic retrans-mission request (HARQ) protocol over block-fading wiretap channels. The transmitter has no instantaneous channel state information (CSI) available from either main channel or the eavesdropper channel, hence the coding rates cannot be adapted to instantaneous channel conditions. We investigate the outage performance for two schemes of INR secure HARQ protocols: case 1) when there exists two reliable multi-bit feedback channels from both legitimate receiver and eavesdropper to the transmitter carrying a function of outdated CSI, case 2) when there is a multi-bit feedback channel only from legitimate receiver. In both cases, we demonstrate that using the information carried via multi-bit feedback channels, the transmitter can adapt the coding rates in order to achieve a better secrecy throughput using a smaller number of transmissions comparing to the ACK/NACK feedback channel model. For some parameters, our rate adaptation protocol achieves a strictly positive secrecy throughput whereas it is equal to zero for the protocol with ACK/NACK feedback. We show that for some set of parameters, the loss of secrecy throughput between case 1 and case 2 is very small compared to the gain provided by both protocols.

Mots clés: secrete communications; feedback; HARQ; wiretap channel

Domaines: Traitement du signal et de l'image [eess.SP]; Théorie de l'information [cs.IT]; Réseaux et télécommunications [cs.NI]

Zeina Mheich, Maël Le Treust, Florence Alberge, Pierre Duhamel. Rate Adaptation for Incremental Redundancy Secure HARQ. IEEE Transactions on Communications, 2016, 64 (2), pp.765-777. ⟨10.1109/TCOMM.2015.2514284⟩. ⟨hal-01273989⟩