Introduction

Scientific and technological objectives

The main objective of UCELLS project is to study and to demonstrate the Cellular UWB capabilities employing a spectrum monitoring system based on a high performance ADC in order to efficiently enable coexistence and compatibility of UWB-based wireless communications with existing and future mobile and fixed wireless systems.

UCELLS pushes towards a scenario of application of UWB systems/devices in cellular-like operation. Figure 1showsthe Cellular-UWB concept envisaged in UCELLS. In this figure it is shown a set of UWB transceivers inside the UWB Access Node coverage area. The transceiver operational parameters (transmitter power, UWB channel, etc.) are assigned by the central node (UWB access point) shown in the Figure 1.

Figure 1: Cellular UWB functionalities and management by several UWB access nodes

UCELLS project will develop a Cellular–UWB architecture incorporating channel management and power-flow control strategies. This architecture comprises a Radio-over-Fibre infrastructure to interconnect a number of monitoring nodes to a control point which comprise Photonic-ADC and digital procesing capabilities to undertake interference evaluation algorithms. On this platform, it will be also implemented a UWB power-flow control technique for the cellular service feasibility demonstration.

The UWB access node requires the development of an UWB spectrum monitoring platform and distributed radio-over-fibre (RoF) remote antennas, comprising a set of monitoring nodes located at specific points in the UWB coverage area (building, facility, etc.) connected to a central node by an inexpensive fibre infrastructure. This platform enables the real-time monitoring of the whole UWB band and beyond in order to enable spectral measurement of the UWB power interfering over other licensed and unlicensed services operating at lower frequencies (eg. GSM, PCS), at the same frequency range (e.g. 802.11) or emerging technologies targeted to operate at higher frequencies (e. g. WiMAX).

This architecture implements interference-monitoring algorithms to guarantee no-interference of the UWB terminals inside the coverage area over other wireless services. The monitoring algorithm will be a signal processing development addressing the impulsive nature of UWB based on time/frequency analysis techniques on the data collected by the Ph-ADC where deployed.

A 3D UWB interference model and estimation algorithm is incorporated in the architecture. The algorithm relies on the spectral power levels gathered by the UWB sensor in the coverage area. The algorithm is based on UWB propagation models available in the literature and could take advantage of the impulsive nature of UWB which allows precise location features to be included in a cost-effective way.

The Cellular-UWB architecture requires a power-flow control and channel management strategy in a simple way. The most straight forward implementation is based on sending power control commands to the UWB terminals within the coverage area to adjust their EIRP. Enhanced UWB terminals supporting power-flow control and channel management strategy will be developed inside the consortium, as a technological breakthrough.

All the key technologies required in UCELLS approach will be developed by the consortium based mainly on COTS with few internal developments.