Peter Van Wesemael

A 5mm 2 40nm LP CMOS 0.1-to-3GHz multistandard transceiver

The trend in wireless communication where terminals give their users ubiquitous access to a multitude of services drives the development of Software-Defined Radio (SDR) in deeply scaled CMOS. This is enhanced with the advent of LTE, a standard that is inherently so flexible that an SDR is its most economical implementation. This work presents an answer to that need with the development of a complete transceiver with RF, baseband and data converter circuits in 40nm LP CMOS.

Digital and Analog Solution for Low-Power Multi-Band Sensing

Since the introduction of Opportunistic Spectrum Access as a new communication paradigm, research has focused on the introduction of improved techniques for spectrum sensing, establishing both theoretical foundations and building experimental prototypes proving the feasibility of spectrum sensing. None of the existing demonstrations however focused on the practical design constraints that have to be considered when using those techniques in low-power and low-cost hand held devices. The goal of this demo is to show the feasibility of spectrum sensing using reconfigurable analog and digital building blocks that have been designed to meet power, cost and area constraints of future opportunistic access devices that can access and sense a broad range of frequency bands. While the analog and digital building blocks have been designed for a broad range of sensing scenarios, focus in this demo will be on analog and digital multi-band sensing.

An integrated reconfigurable engine for multi-purpose sensing up to 6 GHz

We demonstrate a reconfigurable engine for multipurpose spectrum sensing within the cost and power constraints of mobile devices. The analog part builds up on the Scaldio reconfigurable analog front-end [1]. The digital part is an innovative Digital Front-end for Sensing capable of performing a range of sensing algorithms [3], which has now been fully implemented as a chip. The goal of this demo is the first demonstration of the digital chip, integrated with an analog front-end, enabling real-time validation of the sensing engine. The setup is validated for DVB-T and LTE, two important candidates for future DySPAN networks, as well as for very fast spectrum sweeping. This is the first integrated low power solution that can achieve such a very fast spectrum sweeping, thanks to the integration of two innovative components.

REM-enabled opportunistic LTE in the TV band

In this demonstration paper we describe a prototype of an LTE system deployment that opportunistically exploits the spectral white spaces in the upper UHF TV bands, intelligently guided in its spectum access by a radio environment map (REM). The architecture is modular in the sense that interfaces are generic and minimal. In the proposed demo we will illustrate how information of primary transmitters and other secondary transmitters as well as estimates of the radio field strength over frequency, time and space can be made available and exploited by a secondary TDD-LTE base station to make judicious decisions on its spectral occupation.

Experimental assessment of tradeoffs among spectrumsensing platforms

This paper reports experimental results comparing the performance of four platforms employed in spectrum sensing and dynamic spectrum access research: a sensing engine developed at imec and built around a prototype RFIC; the Universal Software Radio Peripheral (USRP) with the Iris software defined radio (SDR) solution; the TelosB sensor network platform; and the Wi-Spy low cost spectrum sensor solution targeted at the ISM band. We use experimental data to derive the receiver operating characteristics (ROC) of each of the four platforms. We observe that for low signal powers, narrow bandwidth signals, high shadowing, or stringent probability of false alarm (PFA) requirements tradeoffs among the platforms tested are most pronounced, whereas for high signal powers, large bandwidths, stable environments, and more flexible PFA requirements less expensive, commercial-off-the-shelf equipment performs sufficiently well.

Versatile Spectrum Sensing on Mobile Devices

Spectrum sensing is a key aspect in the realization of opportunistic radios, which will allow a significantly more efficient usage of the scarce spectrum resources. This paper presents a solution to upgrade mobile devices with spectrum sensing capabilities. A versatile digital component is proposed to meet a wide variety of use cases, at low cost and low power overhead. Complementary reconfigurable analog front-ends make the radio ready for upgrading wireless connectivity thanks to availability of information on spectrum occupancy.

Two days of European spectrum: Preliminary analysis of concurrent spectrum use in seven European sites in GSM and ISM bands

We report initial results from 48 hour spectrum occupancy measurement campaign that was done in time-correlated fashion in seven different European locations. We give a description of the measurement campaign and provide results from our preliminary analysis of overall duty cycle in the frequency range 110-3000 MHz. The paper particularly focuses on traffic and duty cycle patterns in GSM 900 and GSM 1800 bands. For the sake of completeness, we also discuss ISMband utilization in two of our measurement sites. We show that spectrum utilization is generally low, but that variance between frequency bands and locations is significant, which means that any statistical claims on occupancy statistics need to be done carefully before regulatory claims are made.

Performance evaluation of sensing solutions for LTE and DVB-T

Since the introduction of the Opportunistic Spectrum Access paradigm, focus has been on the development of sensing algorithms. Many of those techniques have been verified only through simulations. A small set of the techniques has been verified using off-the-shelf hardware, with limited capabilities, and spectrum analyzers with very good performance, however not realistic for low-power handheld solutions. In this paper, we propose sensing functionality for sensing of LTE and DVB-T signals. This functionality is then verified using a prototype RF front-end that is a realistic candidate for future Software Defined Radio (SDR) handheld solutions. The performance achieved with this front-end is also compared with the spectrum analyzer performance, for the same functionality. We conclude that the prototype achieves a sensing performance within 12dB of the performance achieved by the test equipment when using simple energy detection functionality. In the case of feature based sensing both systems achieve similar performance. In terms of sensitivity, the considered DVB-T sensing functionality achieves the target detection performance up to −102dBm with the sensing prototype over a bandwidth of 8 MHz and averaging 9 OFDM symbols.

Spectrum sensing for cognitive wireless applications inside aircraft cabins

Wireless intra-aircraft communication is expected to be the enabler for more flexible avionic systems and the reduction of weight and cost in system installations. An alternative to the usage of a dedicated frequency band for wireless intra-aircraft avionics could be the usage of a virtually unregulated ISM band. Cognitive radio techniques could be used to increase system robustness in the likely case of interferences in this kind of frequency bands. A cognitive wireless cabin management system is discussed as a use-case for the validation of this approach. Using the mobile cognitive radio testbed of the FP7 project CREW, spectrum sensing experiments are carried out in a realistic aircraft cabin environment as a baseline for the development of suitable cognitive protocols and to record interference scenarios for the further system design.

Performance evaluation of single-chip spectrum sensing platform for portable spectrum measurements

We present results from the comparison of measurements between dedicated embedded spectrum sensing chip targeting low-cost and low-power applications and a high-end spectrum analyzer. We use different signal types, including actual spectrum usage measured simultaneously with the two devices. We analyze the typical problems such devices suffer from. Finally we also study how to estimate the spectrum sensing results once the device type is taken into account.