Digital Decoding inside a cell phone

Jason Angle uses a form of Viterbi decoding for his Quantum Communication invention in my novel Entangled. Most digital radios, including cell phones, have this type of decoding, but what is Viterbi decoding?

Viterbi decoding is used in a digital radio receiver. Most of you have cell or smartphones. The voice you hear or the text message you see or the web page you look at was transmitted from a base station to your phone as digital information, received by it, and processed by a small computer. Part of the processing is a best guess at an incoming sequence of bits. Viterbi Decoding been used for decades and the inventor is still alive breathing life into new stuff - Andrew Viterbi of QualComm

When a radio sends digital information, it sends it in radio waves, one digital bit at a time. Those waves fly from your phone, through walls, bouncing off trees, buildings, water, you name it. When the waves get to a base-station, those ugly towers dotting the highways, the real wave adds to all the bounced waves and some good old-fashioned radio noise. That confuses the receiver, maybe enough that half the bits coming in are guessed wrong. Texting messages would look like gibberish, more so than the sender intended - LOL ROTFL u c da point.

Cleaning up this mess, decoding the digital bits, takes a bit of computing. First, take all the waves and noise for each bit, line them up, and feed them to a decoder. The decoder runs through all possible combinations of a fixed length. For example, a length of 4 bits means the decoder will test 16 possible combinations, starting at 0000, then 0001, up to 1111. The best matching sequence to the incoming data is chosen as the sequence for those 4 bits. There could be a bit error or two, but it's pretty good if the signal is strong enough, more correctly if the signal is a lot stronger than the radio noise.

That's the basics of Viterbi decoding. In Entangled I fictionalized a super Viterbi algorithm just because I needed something with a flashy name that some people might recognize. If you're interested more in Viterbi decoding, or algorithms, just search it!