Software-defined Cognitive Radio Research Articles

Energy-aware spectrum coordination with intelligent frequency-hopping for software defined networks

Software-defined Cognitive radio (CR) networking is considered a promising communication paradigm that can deliver huge spectrum opportunities for enabling massive deployment for wireless Internet-of-Things (IoT) applications and services. An important challenge in this domain is how to provide effective energy-efficient distributed spectrum coordination mechanisms (known as Spectrum Rendezvous), through which the CR IoT users can opportunistically coordinate their transmissions over the idle licensed frequency channels without relying on the existence of a dedicated common control channel (CCC). This paper proposes a novel frequency hopping (FH) distributed rendezvous mechanism for CR-capable IoT (CR-IoT) networks using grid-based quorum systems, referred to as adaptive grid-based quorum channel-hopping scheme. The proposed quorum-based scheme divides the time into equidistant cycle segments, referred to as quorum-based FH intervals. Each quorum interval consists of equal-duration beaconing intervals, each associated with a licensed channel. According to the proposed algorithm, each CR-IoT device randomly selects awake-sleep schedules based on the adopted quorum system structure. Any two devices can exchange their control information over the assigned channels of their common awake beaconing intervals. The proposed algorithm provides probabilistic guarantees on the successful rendezvous (RDV) between any two CR-IoT users within a single quorum-based FH interval (cycle) and dynamically adjusts the adopted QS structure based on the time-varying traffic load in the CR-IoT network such that the RDV probability and the expected average time to rendezvous improve with the least possible energy consumption. Compared to reference design schemes, the simulation results demonstrate that the proposed algorithm significantly increases the RDV probability, reduces the average rendezvous time, and reduces the energy consumption per successful RDV.

SDN‐enabled Cognitive Radio Network Architecture

In this study, a new network architecture based on the software-defined networking (SDN) approach is proposed for cognitive radio networks (CRNs). The proposed network architecture [software-defined cognitive radio (SDCR)] assumes the responsibilities of network resource management for CRNs and provides a dynamic spectrum management mechanism with an SDN controller. In this way, the dependency of network users on base stations is reduced in dynamic cognitive radio environments, and network performance is improved by delegating some of the management responsibilities to the controller. The performance analysis of the SDCR is carried out through the RIVERBED MODELER simulation software. End-to-end delays and packet loss rates for the primary network are investigated by selecting different offered loads for secondary users. In addition, for the equal and different packet sizes, primary network and SDCR throughput are examined and network performance is improved by using channel bonding technique. The results indicate that the SDCR outperforms the traditional CRN architecture, in terms of the throughput, and the proposed architecture can provide effective performance. Bit error rate parameter is investigated in the study and the energy consumption parameter of the SDCR is also compared with the cognitive radio wireless network.

MEMS-based RF channel selection for true software-defined cognitive radio and low-power sensor communications

An evaluation of the potential for MEMS technologies to realize the RF front-end frequency gating spectrum analyzer function needed by true software-defined cognitive radios and ultra-low-power autonomous sensor network radios is presented. Here, RF channel selection, as opposed to band selection that removes all interferers, even those in band, and passes only the desired channel, is key to substantial potential increases in call volume with simultaneous reductions in power consumption. The relevant MEMS technologies most conducive to RF channel- selecting front-ends include vibrating micromechanical resonators that exhibit record on-chip Qs at gigahertz frequencies; resonant switches that provide extremely efficient switched-mode power gain for both transmit and receive paths; medium-scale integrated micromechanical circuits that implement on/off switchable filter-amplifier banks; and fabrication technologies that integrate MEMS together with foundry CMOS transistors in a fully monolithic low-capacitance single-chip process. The many issues that make realization of RF channel selection a truly challenging proposition include resonator drift stability, mechanical circuit complexity, repeatability and fabrication tolerances, and the need for resonators at gigahertz frequencies with simultaneous high Ω (>30,000) and low impedance (e.g., 50 W for conventional systems). Some perspective on which resonator technologies might best achieve these simultaneous attributes is provided.

ESSAY - Spectrum Synergy: Policy Opportunities to Promote Communications and Information Flow in Wireless Networks

Abstract Will consumers and democracy benefit or lose from future mobile policy? In this essay that introduces the “Spectrum for Democracy” special issue of Journal of Information Policy, Dr. Riley argues that the key question is whether national and international policy will facilitate or frustrate the opportunities that wireless presents. To address the biggest challenges, he advocates emphasis on “Super Wi-Fi,” increased competition, spectrum standardization, interoperable architectures, mobile broadband universal service, and resistance to state censorship. In the long-term, Riley says, spectrum management should move away from the current model to a completely opportunistic, software-defined cognitive radio technology.

ESSAY - Spectrum Synergy: Policy Opportunities to Promote Communications and Information Flow in Wireless Networks

Abstract Will consumers and democracy benefit or lose from future mobile policy? In this essay that introduces the “Spectrum for Democracy” special issue of Journal of Information Policy, Dr. Riley argues that the key question is whether national and international policy will facilitate or frustrate the opportunities that wireless presents. To address the biggest challenges, he advocates emphasis on “Super Wi-Fi,” increased competition, spectrum standardization, interoperable architectures, mobile broadband universal service, and resistance to state censorship. In the long-term, Riley says, spectrum management should move away from the current model to a completely opportunistic, software-defined cognitive radio technology.

OPPORTUNISTIC APPROACH TO EXPLOIT WIRELESS SPECTRUM BY USE OF COGNITIVE RADIO

Cognitive radio (CR) technology is envisaged to solve the problems in wireless networks resulting from the limited available spectrum and the inefficiency in the spectrum usage by exploiting the existing wireless spectrum opportunistically. In this paper, intrinsic properties and research on software defined cognitive radio (SDCR) are presented. Firstly brief introduction of Cognitive Radio is given along with its architecture. Then spectrum management of Cognitive Radio ad hoc networks (CRAHNs) and their main features like spectrum sensing, spectrum decision, spectrum selection and spectrum mobility are defined. At the end, Software Defined Cognitive Radio (SDCR), its hardware and software platform, along with research topics on SDCR are defined