Dominique Nussbaum

Blind Spectrum Sensing for Cognitive Radio Based on Model Selection

Cognitive radio devices will be able to seek and dynamically use frequency bands for network access. This will be done by autonomous detection of vacant sub-bands in the radio spectrum. In this paper, we propose a new method for blind detection of vacant sub-bands over the spectrum band. The proposed method exploits model selection tools like Akaike information criterion (AIC) and Akaike weights to sense holes in the spectrum band. Specifically, we assume that the noise of the radio spectrum band can still be adequately modeled using Gaussian distribution. We then compute and analyze Akaike weights in order to decide if the distribution of the received signal fits the noise distribution or not. Our theoretical result are validated using experimental measurements captured by Eurecom RF Agile Platform. Simulations show promising performance results of the proposed technique in terms of sensing vacant sub-bands in the spectrum.

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.

A series of trials in the UK as part of the Ofcom TV white spaces pilot

TV White Spaces technology is a means of allowing wireless devices to opportunistically use locally-available TV channels (TV White Spaces), enabled by a geolocation database. The geolocation database informs the device of which channels can be used at a given location, and in the UK/EU case, which transmission powers (EIRPs) can be used on each channel based on the technical characteristics of the device, given an assumed interference limit and protection margin at the edge of the primary service coverage area(s). The UK regulator, Ofcom, has initiated a large-scale Pilot of TV White Spaces technology and devices. The ICT-ACROPOLIS Network of Excellence, teaming up with the ICT-SOLDER project and others, is running an extensive series of trials under this effort. The purpose of these trials is to test a number of aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services., and the performances of the white spaces devices, among others. An additional key purpose is to undertake a number of research investigations such as into aggregation of TV White Space resources with conventional (licensed/unlicensed) resources, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper describes our trials, their intentions and characteristics, objectives, and some early observations.

Demo: OpenAirInterface: an open LTE network in a PC

LTE 4G cellular networks are gradually being adopted by all major operators in the world and are expected to rule the cellular landscape at least for the current decade. They will also form the starting point for further progress beyond the current generation of mobile cellular networks to chalk a path towards fifth generation mobile networks. The lack of open cellular ecosystem has limited applied research in this field within the boundaries of vendor and operator R&D groups. Furthermore, several new approaches and technologies are being considered as potential elements making up such a future mobile network, including cloudification of radio network, radio network programability and APIs following SDN principles, native support of machine-type communication, and massive MIMO. Research on these technologies requires realistic and flexible experimentation platforms that offer a wide range of experimentation modes from real-world experimentation to controlled and scalable evaluations while at the same time retaining backward compatibility with current generation systems. In this work, we present OpenAirInterface (OAI) as a suitably flexible platform towards open LTE ecosystem and playground [1]. We will demonstrate an example of the use of OAI to deploy a low-cost open LTE network using commodity hardware with standard LTE-compatible devices. We also show the reconfigurability features of the platform.

Some Initial Results and Observations from a Series of Trials within the Ofcom TV White Spaces Pilot

TV White Spaces (TVWS) technology allows wireless devices to opportunistically use locally-available TV channels enabled by a geolocation database. The UK regulator Ofcom has initiated a pilot of TVWS technology in the UK. This paper concerns a large- scale series of trials under that pilot. The purposes are to test aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white space devices, among others. An additional key purpose is to perform research investigations such as on aggregation of TVWS resources with conventional resources and also aggregation solely within TVWS, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper provides an update on the trials, giving an overview of their objectives and characteristics, some aspects that have been covered, and some early results and observations.

Open Platform for Prototyping of Advanced Software Defined Radio and Cognitive Radio Techniques

This paper presents the ANR project IDROMel, which aims at developing reconfigurable SDR (Software Defined Radio) and Cognitive Radio (CR) equipments. IDROMel is a 3 years project that started in 2005 and finishes in 2009. The main objective of IDROMel is to define, develop and validate a powerful SDR and CR platform combining very last technology progresses. The platform includes software parts (reconfigurable protocol stacks) and hardware parts (a base band board and a Radio Frequency Front end, RF). Both parts are presented in this paper.)

Broadband wireless channel measurements for high speed trains

We describe a channel sounding measurement campaign for cellular broadband wireless communications with high speed trains that was carried out in the context of the project CORRIDOR. The campaign combines MIMO and carrier aggregation to achieve very high throughputs. We compare two different scenarios, the first one reflects a cellular deployment, where the base station is about 1km away from the railway line. The second scenario corresponds to a railway deployed network, where the base station is located directly next the railway line. We present the general parameters of the measurement campaign and some results of Power Delay Profiles and Doppler Spectra and their evolution over time. Finally we present a simple channel model that captures the main effects observed in the measurements.

An all-IP software radio architecture under RTLinux

This paper presents an overview of software radio architectures for testing quality-of-service (QoS) aware IP data services over a typical third-generation radio interface. The testbed is implemented using a hard real-time micro-kernel known as RTLinux, running beneath the Linux operating system, for providing real-time end-to-end functionality. The testbed runs on a variety of Intel Pentium-based computing platforms including laptops and high-end servers. Layers 1 and 2 are compliant with the 3GPP specifications forTdd operation and layer 3 provides a direct interconnection with an IPv6 core network. The intent is to study the impact of an ip core network and QoS constraints on the physical and link layers as well as the co-design of physical layer configurations and IP layer networking.RésuméCet article présente un aperçu des architectures radio logicielles destinées aux tests de la qualité de service (Quality of Service: QoS) pour des services IP de transmission de données à travers des interfaces radio 3e génération. Le banc d’essai est réalisé en utilisant un micro-noyau temps réel comme RTLinux, qui tourne sous un système d’exploitation Linux, assurant ainsi des fonctionnalités temps réel de bout en bout. Le banc d’essai consiste en une plateforme comprenant des PC portables et des serveurs à base de processeurs Intel Pentium. Les couches 1 et 2 sont totalement compatibles avec les spécifications de la norme 3GPP pour le modeTdd. Quant à la couche 3, elle est conçue pour offrir une interconnexion directe avec des réseaux IPv6. Notre objectif étant d’étudier, aussi bien, l’impact des architectures ip et des contraintes de la qualité de service sur les couches physique et de liaison, que la conception conjointe des configurations de la couche physique et de la couche IP.

Demo: Closer to Cloud-RAN: RAN as a Service

Commoditization and virtualization of wireless networks are changing the economics of mobile networks to help network providers (e.g., MNO, MVNO) move from proprietary and bespoke hardware and software platforms toward an open, cost-effective, and flexible cellular ecosystem. In addition, rich and innovative local services can be efficiently created through cloudification by leveraging the existing infrastructure. In this work, we present RANaaS, which is a cloudified radio access network delivered as a service. RANaaS provides the service life-cycle of an on-demand, elastic, and pay as you go 3GPP RAN instantiated on top of the cloud infrastructure. We demonstrate an example of real-time cloudified LTE network deployment using the OpenAirInterface LTE implementation and OpenStack running on commodity hardware as well as the flexibility and performance of the platform developed.

Adaptive Complexity Equalization for the Downlink in WCDMA Systems

We consider the issue of terminal reconfigurability in the downlink of WCDMA. For the purpose of optimizing power consumption in mobile terminals, we propose an adaptive- complexity equalization algorithm, which adapts the equalization length to the environment. A simple approach in WCDMA systems consists of computing the equalizer coefficients in frequency domain, and carry out channel equalization in time domain. The equalizer can be easily computed in frequency domain from channel estimates, which are generally obtained through pilot symbols. In our work, we decouple the task of adaptive complexity equalization in two parallel operations: variable length equalization and equalization length control. We propose a practical scheme to reduce equalization complexity by prewindowing in frequency domain and performing IFFT of variable length. An element of length control monitors the equalizer coefficients, updating the equalizer length at each stage. Both simulation and experimental results in outdoor-to- indoor scenarios show good performance and significant power savings with respect to full length equalization.