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In this work, we examine cognitive radio networks, where secondary users may act as relays for messages sent by the primary user, hence offering performance improvement of primary transmissions, while at the same time obtaining more…

Information Theory · Computer Science 2019-08-29 Athanasios Papadopoulos , Nestor D. Chatzidiamantis , Leonidas Georgiadis

In Cognitive Radio (CR) networks, multiple secondary network users (SUs) attempt to communicate over wide potential spectrum without causing significant interference to the Primary Users (PUs). A spectrum sensing algorithm is a critical…

Networking and Internet Architecture · Computer Science 2013-04-04 Yuan Lu , Alexandra Duel-Hallen

We investigate the coexistence of underlay spectrum sharing in cell-free massive multiple-input multiple-output (MIMO) systems. A primary system with geographically distributed primary access points (P-APs) serves a multitude of primary…

Information Theory · Computer Science 2021-04-21 Diluka Loku Galappaththige , Gayan Amarasuriya Aruma Baduge

In this paper, we study and analyze fundamental throughput and delay tradeoffs in cooperative multiple access for cognitive radio systems. We focus on the class of randomized cooperative policies, whereby the secondary user (SU) serves…

Networking and Internet Architecture · Computer Science 2014-04-25 Mahmoud Ashour , Amr A. El-Sherif , Tamer ElBatt , Amr Mohamed

This paper addresses the problem of resource allocation for systems in which a primary and a secondary link share the available spectrum by an underlay or overlay approach. After observing that such a scenario models both cognitive radio…

Information Theory · Computer Science 2016-12-21 Alessio Zappone , Bho Matthiesen , Eduard A. Jorswieck

Coexistence by means of shared access is a cognitive radio application. The secondary user models the slotted primary users channel access as a Markov process. The model parameters, i.e, the state transition probabilities (alpha,beta) help…

Information Theory · Computer Science 2014-02-21 Ankit Kaushik , Friedrich K. Jondral

Dynamic spectrum access allows the unlicensed wireless users (secondary users) to dynamically access the licensed bands from legacy spectrum holders (primary users) either on an opportunistic or a cooperative basis. In this paper, we focus…

Networking and Internet Architecture · Computer Science 2015-12-04 Nima Namvar , Fatemeh Afghah

Powerful spectrum handover schemes enable cognitive radios (CRs) to use transmission opportunities in primary users' channels appropriately. In this paper, we consider the cognitive access of primary channels by a secondary user. We…

Performance · Computer Science 2012-01-04 Hossein Shokri-Ghadikolaei , Mohammad Mozaffari , Masoumeh Nasiri-Kenari

We consider power control in cognitive radio networks where secondary users identify and exploit instantaneous and local spectrum opportunities without causing unacceptable interference to primary users. We qualitatively characterize the…

Networking and Internet Architecture · Computer Science 2009-03-17 Wei Ren , Qing Zhao , Ananthram Swami

In this paper, an underlay cognitive radio network that consists of an arbitrary number of secondary users (SU) is considered, in which the primary user (PU) employs Type-I Hybrid Automatic Repeat Request (HARQ). Exploiting the redundancy…

Information Theory · Computer Science 2015-06-23 Roghayeh Joda , Michele Zorzi

In this paper, we investigate the maximum throughput of a saturated rechargeable secondary user (SU) sharing the spectrum with a primary user (PU). The SU harvests energy packets (tokens) from the environment with a certain harvesting rate.…

Information Theory · Computer Science 2014-07-10 Ahmed El Shafie , Tamer Khattab , H. Vincent Poor

In this paper, we present a framework for distributively optimizing the transmission strategies of secondary users in an ad hoc cognitive radio network. In particular, the proposed approach allows secondary users to set their transmit…

Networking and Internet Architecture · Computer Science 2016-02-05 Orestis Georgiou , Mohammud Z. Bocus , Shanshan Wang

In this paper, we investigate a time-slotted cognitive setting with buffered primary and secondary users. In order to alleviate the negative effects of misdetection and false alarm probabilities, a novel design of spectrum access mechanism…

Information Theory · Computer Science 2013-03-26 Ahmed El Shafie

We consider the problem of spectrum sharing in a cognitive radio system consisting of a primary user and a secondary user. The primary user and the secondary user work in a non-cooperative manner. Specifically, the primary user is assumed…

Information Theory · Computer Science 2018-05-08 Xingjian Li , Jun Fang , Wen Cheng , Huiping Duan , Zhi Chen , Hongbin Li

In this work, a new transmission scheme, signal space cognitive cooperation, is introduced by applying the idea of signal space diversity in an underlay spectrum sharing decode-and-forward multi-relay cooperative network. In the proposed…

Signal Processing · Electrical Eng. & Systems 2019-01-11 Eylem Erdogan , Ali Afana , Hamza U. Sokun , Salama Ikki , Lutfiye Durak-Ata , Halim Yanikomeroglu

This paper provides a survey of the state-of-the-art information theoretic analysis for overlay multi-user (more than two pairs) cognitive networks and reports new capacity results. In an overlay scenario, cognitive / secondary users share…

Information Theory · Computer Science 2015-10-26 Diana Maamari , Daniela Tuninetti , Natasha Devroye

We consider the problem of Spectrum Sensing in Cognitive Radio Systems. We have developed a distributed algorithm that the Secondary users can run to sense the channel cooperatively. It is based on sequential detection algorithms which…

Information Theory · Computer Science 2008-09-19 Vinod Sharma , ArunKumar Jayaprakasam

This paper proposes a new cooperative protocol which involves cooperation between primary and secondary users. We consider a cognitive setting with one primary user and multiple secondary users. The time resource is partitioned into…

Networking and Internet Architecture · Computer Science 2014-07-03 Ahmed El Shafie , Tamer Khattab

Due to ever increasing usage of wireless devices and data hungry applications, it has become necessary to improve the spectral efficiency of existing wireless networks. One way of improving spectral efficiency is to share the spectrum…

Signal Processing · Electrical Eng. & Systems 2019-05-14 Shailesh Chaudhari

This letter studies a time-slotted multiple-access system with a primary user (PU) and a secondary user (SU) sharing the same channel resource. We propose a novel secondary access protocol which alleviates sensing errors and detects the…

Networking and Internet Architecture · Computer Science 2016-11-01 Ahmed El Shafie