Time-Domain Wireless Channel Sounding Using Software Defined Radio

In this work we present low cost time-domain wireless channel sounding using software defined radio (SDR). We performed SDR based time-domain wireless indoor channel sounding using random sequences. We used three random sequences for channel measurements because of their excellent auto-correlation and cross-correlation properties. More specifically PN code sequence, Gold code sequence, and Zadoff-Chu sequences are used. The channel measurements are performed in indoor laboratory environment at two locations at RF frequency of 5.2 GHz and 5.8 GHz respectively. Channel measurements are performed by transmitting sequences with software defined radio in indoor laboratory environment.

I. Introduction

Channel measurements and characterization is popular domain for characterization of different wireless channels. Traditionally, this is done with the help of network analyzer and customized channel sounders which are not only costly but bulky and difficult to deploy in certain type of radio environment. Alternative to this is software defined radio based channel sounding. SDR based channel sounding has huge advantage over traditional channel sounders as it is reprogrammable, light-weight, cost-effective and scalable solution for channel measurements and characterization. SDR based channel sounders can be deployed in difficult radio environment where the weight and size of traditional channel sounders become big problem. For example air-to-air radio channel measurements in unmanned aerial vehicles (UAV) communication. SDR based channel measurement campaigns have been carried out in different radio environments. Previously GNU Radio, MATLAB/Simulink and LabView are used for SDR based development. SDR based channel sounding using GNU radio is detailed in [1] and SDR channel sounding using GNU radio in industrial environment is presented in [2]. SDR based channel sounding can also be extended to MIMO channel measurement [3]. It is suitable platform for testing and implementation of wireless communication systems and part of such complete end-to-end implementations. OFDM based channel sounding using SDR is presented in [4]. Different techniques for SDR based wireless channel sounding for rapid radio propagation measurement is discussed in [5]. Previously, we reviewed SDR platforms for BER measurements [6] and measured BER performance of QPSK receiver using USRP X310 in anechoic chamber under different noise levels [7]. Rest of the paper is organized in the following sections. Section II includes channel characterization discussion and relevant channel characterization parameters. Section III details time-domain channel sounding using software defined radio. It reviews channel sounding sequences and measurement trade-offs. Section IV contains experimental setup. Section V is about measurements. Conclusion and future aspects are presented in Section VI.