Ultra-wideband Concepts for Ad-hoc Networks

Rezultaty

The design, manufacturing and test of a set of 16 UWB transmitters (pulse generators) was also completed under the UCAN project scope. They were developed in order to evaluate the interference of UWB devices over other communication and control systems. This development was out of scope of the initial planning an purposes of the UCAN project for T31, but due to the interest and relevance of the UWB co-existence topics, specially when related to the agreement on a UWB regulation and standard, partners involved in T31 decided to develop these transmitters and be able to perform some tests and co-existence trials.

A demonstration platform, composed of two RF components (TX and RX), an ART board (embedding a Power PC and Altera FPGA), and a Nallatech board (embedding a Xilinx FPGA), has been implemented. It is capable of point-to-point communication with up to 12.5 Mbps data throughput. The RF is based on the Impulse Radio Ultra-Wide Band (IR-UWB) technology. The modulation is based on pulse position (M-PPM). The platform provides also ranging services, with a ranging precision of +/- 15 cm in line-of-sight (LOS) conditions. A channel coder/decoder based on convolutional encoder and Viterbi decoder is implemented. A basic medium access control (MAC) function has been implemented as well.

In this first document on the channel measurements and modelling, all the tasks, procedures and results related to this topic are presented. The content of this report is organised as follows: - Measurement Set-up: This section includes a whole description of the channel sounding campaigns carried out by the consortium members. Not only the employed components and specifications (distances and frequencies) are covered, but also the block diagram and calibration procedures are explained. - Measurement Environment: The presentation of the different scenarios where the measurement campaigns were performed is covered in this section. Maps containing the transmitter location and the different receiver ones, within the labs, corridors, halls and the rest of the scenarios are included. Besides, the process followed to study the spatial variations (grid), is also analysed. - Post-Processing: Apart from an introduction to the special requirements of the UWB signal treatment, the results of the channel characterization, both time and frequency domain, are included. Moreover, the specific post-processing for the employed scenarios (threshold, FFT considerations, etc.) and several explanatory figures are added. - Channel Model approach: A complete description of the LOS and NLOS channel models is the core of this section. These channel models elections are justified and their building process analysis is included. - Channel Model Results: Finally, the evaluation of the accuracy achieved by these models is presented, through the comparison between parameters extracted from the models realisations and those obtained during the measurement campaigns.

Rezultaty

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