Wavelet Packet Modulation (WPM) uses an arbitrary time-frequency plane tiling to create orthogonal subchannels of different bandwidths and symbol rates in a multichannel system. The Wavelet Packet Tree is implemented by iterating a perfect reconstruction two channel transmultiplexer. We derive operating conditions for the capacity-optimal tree for a given communication channel and power budget. We present a fast tree-selection algorithm which achieves this optimum for the case of a finite complexity transceiver. It is found that optimal-WPM outperforms conventional multichannel systems of equal complexity for ISI channels.
['Donnacha Daly', 'Conor Heneghan', 'Anthony D. Fagan', 'Martin Vetterli']
Optimal Wavelet Packet Modulation under finite complexity constraint