Propagation at millimetric frequencies (30-300 GHz) is highly dependent on tropospheric phenomena such as rain, clouds, fog, and atmospheric gases; all of which combine to cause signal absorption, dispersion and scattering. The need to accurately characterise the signal propagation channel in both time and frequency is essential for cost effective system design.

Knowledge of the channel is also required to minimise interference, determine network throughput and loading, and optimise globally deployable mobile links. The QinetiQ CPAR sounder (a modified version of the commercially available MEDAV sounder) transmits a coded FM waveform in an instantaneous bandwidth of up to 120 MHz at a rate of nearly once every millisecond.

A channel impulse response (CIR) is measured by correlating the received signal with a replica of the waveform generated internally at the receiver. The QinetiQ CPAR wideband sounder offers much richer scientific data than straight-forward continuous wave (CW) measurements, such as Doppler and multipath information.

Channel Sounder Description

• Instantaneous 120 MHz dual channel bandwidth
• Multipath resolution: 15 ns
• Doppler range: ± 500 Hz
• High time resolution measurements
• Long term data capture to DAT
• Deployable in-vehicle for mobile and outdoor use
• Instantaneous dynamic range: 36 dB
• System dynamic range: 76 dB
• Operating frequency: 1.7-2.7 GHz
• Frequency translators allow additional operation at 5, 37 and 60 GHz

Sounder transmitter unit

Channel sounder applications