A method of encoding a first bit and a second bit for transmission on a transmission band is provided. The method includes: mapping, via a mapping component, the first bit and the second bit into a first symbol; mapping, via the mapping component, the first bit and the second bit into a second symbol; dividing, via a dividing component, the transmission band into subcarriers; allocating, via an allocating component, the first symbol to a first subcarrier of the subcarriers; allocating, via the allocating component, the second symbol to a second subcarrier of the subcarriers; and differentially encoding, via a differential encoder, the first symbol and the second symbol.