English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A fundamental problem in cognitive radio systems is that the cognitive radiois ignorant of the primary channel state and the interference it inflicts onthe primary license holder. In this paper we assume that the primarytransmitter sends packets across an erasure channel and the primary receiveremploys ACK/NAK feedback (ARQ) to retransmit erased packets. The cognitiveradio can eavesdrop on the primary's ARQs. Assuming the primary channel statesfollow a Markov chain, this feedback gives the cognitive radio an indication ofthe primary link quality. Based on the ACK/NACK received, we devise optimaltransmission strategies for the cognitive radio so as to maximize a weightedsum of primary and secondary throughput. The actual weight used during networkoperation is determined by the degree of protection afforded to the primarylink. We study a two-state model where we characterize a scheme that spans theboundary of the primary-secondary rate region. Moreover, we study a three-statemodel where we derive the optimal strategy using dynamic programming. We alsoshow via simulations that our optimal strategies achieve gains over the simplegreedy algorithm for a range of primary channel parameters.

Cognitive Radio Transmission Strategies for Primary Erasure Channels