Wednesday, March 22, 2023

# GRAND: A Universal System For Decoding Any Type Of Data

Researchers have developed a novel system that can decode and correct any noise-affected data.

Every data that travels through a communication medium is affected by noise, such as electromagnetic interference from a microwave or Bluetooth device, along the way. Therefore, the data are coded so that when they arrive at their destination, a decoding algorithm can undo the negative effects of that noise and retrieve the original data. These codes that help retrieve original data are known as error-correcting codes.

In error-correcting codes, each code has a particular structure corresponding with a particular, highly complex decoding algorithm, which often requires the use of dedicated hardware.

These codes are redundant series of 1s and 0s added to the end of the original data. The rules for the creation of that redundant bits are stored in a specific codebook. When the coded data and the noise that affected them arrive at their destination, the decoding algorithm looks into its codebook and uses the structure of the redundant bits to guess what the stored information is.

Researchers at MIT, Boston University, and Maynooth University in Ireland have developed a chip that is able to decode any code, regardless of its structure, with maximum accuracy, using a universal decoding algorithm called Guessing Random Additive Noise Decoding (GRAND). The GRAND architecture eliminates the need for multiple, computationally complex decoders.

The GRAND system, unlike traditional error-correcting algorithms, works by guessing the noise that affected the message, and uses the noise pattern to deduce the original information. This new system generates a  series of noise sequences in the order they are likely to occur, subtracts them from the received data, and checks to see if the resulting codeword is in a codebook.

“In a way, it is similar to troubleshooting. If someone brings their car into the shop, the mechanic doesn’t start by mapping the entire car to blueprints. Instead, they start by asking, ‘What is the most likely thing to go wrong?’ Maybe it just needs gas. If that doesn’t work, what’s next? Maybe the battery is dead?” Médard says.

The chip uses a three-tiered structure, starting with the simplest possible solutions in the first stage and working up to longer and more complex noise patterns in the two subsequent stages. Each stage operates independently, which increases the throughput of the system and saves power. Moreover, the device can switch seamlessly between two codebooks.

The chip consists of two static random-access memory chips, one that can crack codewords, while the other loads a new codebook and then switches to decoding without any downtime.

According to the researchers, GRAND enables increased efficiency that could have applications in augmented and virtual reality, gaming, 5G networks, and connected devices that rely on processing a high volume of data with minimal delay.