The spectrum resource in the air becomes more occupied, so it is necessary to increase spectrum efficiency with our purpose to relax more resource. Traditionally, we increase the data rate in the unit frequency band through higher order modulation, orthogonal frequency division multiplexing (OFDM) and pulse shaping. However, another way for improving spectrum efficiency is to reduce the transmitting bandwidth required for unit data rate. From this point of view, the ultra narrow band (UNB) modulation was proposed. UNB modulation is a sort of transmission technique with efficient bandwidth and high data rate. This patent review will highlight recent patents on UNB modulations, and briefly explain their theoretic foundation and key technology.
Keywords: Ultra narrow band (UNB), high efficient modulations, high speed communications, special filters, modulator and demodulator (MODEM), channel coding, wireless communications, orthogonal frequency division multiplexing, Bandwidth, Sinusoidal Carrier, Carrier Energy, Waveform Manipulation Technologies, amplitude modulation, signal bandwidth, Geometric Feature Filters, Wavelet Pass Filters
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