Ultra reliable communication via opportunistic ARQ transmission in cognitive networks

Abstract

This paper presents a novel opportunistic spectrum sharing scheme that applies ARQ protocol to achieve ultra reliability in the finite blocklength regime. A primary user shares its licensed spectrum to a secondary user, where both communicate to the same base station. The base station applies ARQ with the secondary user, which possess a limited number of trials to transmit each packet. We resort to the interweave model in which the secondary user senses the primary user activity and accesses the channel with access probabilities which depend on the primary user arrival rate and the number of available trials. We characterize the secondary user access probabilities and transmit power in order to achieve target error constraints for both users. Furthermore, we analyze the primary user performance in terms of outage probability and delay. The results show that our proposed scheme outperforms the open loop and non-opportunistic scenarios in terms of secondary user transmit power saving and primary user reliability.

Availability-Reliability-Stability Trade-Offs in Ultra-Reliable Energy-Harvesting Cognitive Radio IoT Networks

“…Specifically, the FA application was time-synchronized to the cellular network, and collocating nodes were exploited to prevent interference. Opportunistic transmission for UR interweave CR networks has been analyzed in [20]. To achieve UR communication, an automatic-repeat-request (ARQ) scheme has been adopted for secondary users (SUs).…”

“…Ultra-reliable IoT networks have become one of the most promising paradigms in many future applications; for instance, in IIoT [6]- [9]. To achieve UR communications, several techniques have been proposed in the literature; such as, ARQ-based protocols [20], [45], power control strategies to mitigate interference power [21], [46], [47], relay-based techniques [48], [49], and diversity transmissions [50]- [52]. However, from an implementation perspective, although each approach has its own pros and cons, diversity transmission is the simplest to implement in UR networks, or even modify an existing network operation/configuration to an ultra-reliable one, as it requires no changes to the hardware or framing.…”