Wi-Fi to 5G Radio Link Lab: Walls, Fading and Beamforming from Router to Cell Tower

What is a Radio Link?

A radio link refers to the transmission path between two or more points in a communication system. It involves the emission of electromagnetic waves from a transmitter and their reception by a receiver. In this context, we focus on how these signals navigate through various environments, including obstacles like walls.

The journey of a radio signal is governed by several factors such as free-space path loss, wall attenuation, multipath fading, and beamforming techniques designed to enhance the quality and reliability of the connection.

Key Concepts in Radio Link Propagation

Free-space path loss (FSPL) is a fundamental concept that describes how signal strength decreases with distance. This is due to the spreading out of the electromagnetic waves as they travel through space, which can be calculated using the FSPL formula: L = 32.4 + 20log(f) + 20log(d), where f is the frequency in MHz and d is the distance in km.

Multipath fading occurs when multiple copies of a signal reach the receiver at slightly different times, causing constructive or destructive interference. This phenomenon can significantly degrade the quality of the received signal.

Beamforming Techniques

Beamforming is an advanced technique used to direct radio waves in specific directions, thereby increasing the signal strength and reducing interference from unwanted sources. By adjusting the phase and amplitude of signals transmitted by multiple antennas, beamforming can focus the energy into a narrow beam that targets the receiver.

In practical applications, such as 5G networks, beamforming is crucial for achieving higher data rates and improving coverage in urban environments where signal paths are often obstructed.

Shannon Capacity and MCS Ladder

The Shannon capacity of a communication channel represents the maximum rate at which information can be transmitted over that channel with an arbitrarily low bit error rate. It is given by C = B * log2(1 + S/N), where C is the channel capacity in bits per second, B is the bandwidth in Hz, and S/N is the signal-to-noise ratio.

The Multiple-Input Multiple-Output (MIMO) system uses the MCS ladder to optimize data transmission. Each step on this ladder corresponds to a different modulation scheme and coding rate, allowing for adaptive adjustments based on channel conditions.

Frequently asked questions

Try it live

Everything above runs in your browser — open Wi-Fi to 5G Radio Link Lab: Walls, Fading and Beamforming from Router to Cell Tower and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.