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

In this paper, we consider a cognitive radio (CR) system consisting of aprimary user (PU) and a pair of secondary user transmitter (SUtx) and secondaryuser receiver (SUrx). The SUtx is equipped with a reconfigurable antenna (RA)which divides the angular space into M sectors. The RA chooses one sector amongM sectors for its data transmission to SUrx. The SUtx first senses the channeland monitors the activity of PU for a duration of T_{sen} seconds. We refer tothis period as channel sensing phase. Depending on the outcome of this phase,SUtx stays in this phase or enters the next phase, which we refer to astransmission phase. The transmission phase itself consists of two phases:channel training phase followed by data transmission phase. During the formerphase, SUtx sends pilot symbols to enable channel training and estimation atSUrx. The SUrx selects the best beam (sector) for data transmission and feedsback the index of the selected beam as well as its corresponding channel gain.We also derive the probability of determining the true beam and take intoaccount this probability in our system design. During the latter phase, SUtxsends data symbols to SUrx over the selected beam with constant power {\Phi} ifthe gain corresponding to the selected beam is bigger than the threshold{\zeta}. We find the optimal channel sensing duration T_{sen}, the optimalpower level {\Phi} and a optimal threshold {\zeta}, such that the ergodiccapacity of CR system is maximized, subject to average interference and powerconstraints. In addition, we derive closed form expressions for outage andsymbol error probabilities of our CR system.

On the Spectrum Sensing, Beam Selection and Power Allocation in Cognitive Radio Networks Using Reconfigurable Antennas