Portable and Low Cost Channel Sounding Platform for VHF / UHF IoT Propagation Research

Abstract

This paper presents work into realising a cost-effective and portable platform to support Internet of Things (IoT) propagation research at VHF and UHF. The sounding receiver uses a low cost RTL-SDR, Raspberry Pi and touchscreen. The platform runs dedicated channel sounding DSP algorithms written in Python. The resulting platform is a portable and convenient propagation measurement tool, covering 27MHz to 1.7GHz. Initial results from a city measurement campaign at 71MHz and 869.525MHz are presented, showing channel response and interference.

Design and field trial measurement results for a portable and low‐cost very‐high‐frequency/ultra‐high‐frequency channel sounder platform for Internet of things propagation research

“…The RX data from the RTL-SDR is partitioned into segments of length 2N: rx_sequence_2N[1..2N], which facilitates robust detection of at least one strong correlation peak, regardless of time offset in the captured RX data, compared with the TX PRBS. The overall captured RX data file is then processed in 16 such segments, each of length 2N samples, using the following pseudo-algorithm [6]:…”

“…To assist in the capture of IoT VHF and ultra-high-frequency (UHF) propagation information, a low-cost, portable and frequency-agile system has been created and is described in this paper. The system consists of a fixed transmitter (TX) and a pedestrian portable channel sounding receiver (CSR) [6]. The CSR allows near real-time capture and display of the channel response in operational environments such as urban canyons or remote rural locations.…”