Architectures for Cognitive Radio Testbeds and Demonstrators – An Overview

Wireless communication standards are developed at an ever-increasing rate of pace, and significant amounts of effort is put into research for new communication methods and concepts. On the physical layer, such topics include MIMO, cooperative communication, and error control coding, whereas research on the medium access layer includes link control, network topology, and cognitive radio. At the same time, implementations are moving from traditional fixed hardware architectures towards software, allowing more efficient development. Today, field-programmable gate arrays (FPGAs) and regular desktop computers are fast enough to handle complete baseband processing chains, and there are several platforms, both open-source and commercial, providing such solutions. The aims of this paper is to give an overview of five of the available platforms and their characteristics, and compare the features and performance measures of the different systems

Architecture of a programmable system-on-chip platform for flexible radio processing

The emergence of multiple radio access technologies (RATs) and their continuous evolution, is driving the need for programmable radio processing. Programmable radio devices with run-time flexibility and resource virtualization features will not only enable faster time-to-market, longer lifetime of devices, and universal connectivity, but also act as building blocks for advanced wireless technologies of adaptive and cognitive radios. These requirements have forced a shift from the traditional ASIC approach. However, most existing flexible solutions are based on either fully software-defined or software-controlled approaches that lack the power efficiency, performance and determinism (for real-time constraints) needed for wireless processing. In this thesis, we propose a programmable multi-processor system-on-chip (SoC) platform architecture based on a novel Virtual Flow Pipelining (VFP) framework that aims at striking a balance between flexibility (as provided by SDR) and performance (as provided by ASICs). The key highlights of this concept are a simple task-level programming model for provisioning protocol flows, and the use of dedicated hardware-based OS-like support for controlling their run-time execution. We present the evolution of a clustering-based organization for the SoC with distributed-shared controllers. Clustering along with an inherent architectural support for message passing provides a balance between scalability and hardware overhead. Shared controllers with a pipelined microarchitecture and a separate interconnect for control messaging are designed for low hardware complexity and high performance. The proposed architecture is evaluated by creating a bit- and cycle-accurate model in synthesizable register-transfer-level (RTL). It has been built into a virtual platform for 802.11a transmitter, which has successfully executed single and multiple flows for rates of 6, 12 and 24 Mbps. This thesis also presents a characterization and analysis of the architecture to provide key implications such as control overhead for different task sizes, its impact on cluster size etc.M.S.Includes bibliographical referencesby Onkar Sarod