5G Channel Sounding Basics: Measurements and Test Equipment

This page covers 5G channel sounding basics, including measurements and test equipment.

About Channel

The path between a transmitter and receiver through which information flows (in various forms like electrical, electromagnetic, or binary) is known as a channel. This path can be wired or wireless. Here, we will focus on wireless channels, also known as RF channels.

During wireless system development, a mathematical model of the channel is designed and used during system simulation to achieve desired BER/PER (Bit Error Rate/Packet Error Rate) results at various SNR (Signal-to-Noise Ratio) levels.

Different wireless systems have different channel models based on frequency, terrain, mobility, path loss, and other factors.

During RF channel model development, various parameters such as delay, path loss, absorption, multipath, reflection, fading, and the Doppler effect are considered. These parameters significantly affect the characteristics of the RF channel.

Function of Channel Sounding

The purpose of channel sounding is to understand various characteristics of the RF channel. In other words, channel sounding refers to the measurement or estimation of channel characteristics.

The channel sounding technique employed in 5G networks is known as 5G channel sounding. This aids in channel model development. It also assists in channel estimation and channel equalization algorithms used at complex wireless receivers in 4G and 5G based standards.

Following are the common channel sounding techniques:

• Preamble or Pattern Based: This uses known symbols or patterns available at the receiver. The corrupted symbol or pattern is compared with a reference pattern (already available) to determine channel characteristics for channel sounding. Reference symbols, such as pilots inserted between the OFDM symbols, can also be used for channel estimation.

• Rusk sounding: This technique generates frequency tones across the entire available bandwidth. These tones are transmitted across the path between the transmitter and receiver to determine channel behavior at all frequencies.

5G Channel Sounding Measurements

For 5G channel sounding, the following parameters are used to determine the CIR (Channel Impulse Response) at different millimeter-wave frequencies, such as 28 GHz, 38 GHz, and 72 GHz:

• Instantaneous parameters: Power delay profile, path loss and path delay, AoA (Angle of Arrival), AoD (Angle of Departure), Doppler frequency shift, etc.

• Statistical parameters: Angular speed of AoA and AoD, power angular spectrum, correlation matrix, Rician factor (K), Doppler spectrum, etc.

Keysight 5G Millimeter Wave Channel Sounding Solutions

• Keysight Technologies offers 5G waveform generation and 5G waveform analysis hardware and software.

• The Keysight solution helps in channel impulse response (CIR) estimation.

• The hardware supports up to 44 GHz frequency range with 1GHz bandwidth.

• It supports 4 or 8 number of MIMO channels.

• Visit https://www.keysight.com for more information.

REFERENCE: https://www.5gworkshops.com/5GCM.html