A Sub-Space Method to Detect Multiple Wireless Microphone Signals in TV Band White Space

TL;DR

This paper introduces a two-stage sub-space algorithm designed to reliably detect multiple low-power wireless microphone signals in TV white space, addressing challenges in spectrum sensing for dynamic access.

Contribution

The paper presents a novel sub-space based method specifically tailored for detecting multiple low-power WM signals in TV bands, improving sensing robustness.

Findings

Effective detection of WM signals at -100 to -105 dBm

Algorithm successfully distinguishes WM signals from interference

Experimental validation with real WM signals

Abstract

The main hurdle in the realization of dynamic spectrum access (DSA) systems from physical layer perspective is the reliable sensing of low power licensed users. One such scenario shows up in the unlicensed use of TV bands where the TV Band Devices (TVBDs) are required to sense extremely low power wireless microphones (WMs). The lack of technical standard among various wireless manufacturers and the resemblance of certain WM signals to narrow-band interference signals, such as spurious emissions, further aggravate the problem. Due to these uncertainties, it is extremely difficult to abstract the features of WM signals and hence develop robust sensing algorithms. To partly counter these challenges, we develop a two-stage sub-space algorithm that detects multiple narrow-band analog frequency-modulated signals generated by WMs. The performance of the algorithm is verified by using experimentally captured low power WM signals with received power ranging from -100 to -105 dBm. The problem of differentiating between the WM and other narrow-band signals is left as a future work.