New Spreading Transforms for Fading Channels
We introduce a new class of symbol-spreading transforms that are well-suited for use in errorcontrol coding systems operating in fading channels. These unitary transforms have the property that they allow for the unambigous determination of input symbols from just a single correctly received output symbol. The transforms can be represented using factor graphs that allow for ”fast” encoding. Our simulations show that on channels with fading or interference, systems based on these new transforms can greatly outperform previously proposed systems that use Walsh-Hadamard transforms.