Spread spectrum communications handbook (revised ed.)
Spread spectrum communications handbook (revised ed.)
Scale time offset robust modulation for code division multiaccess
MILCOM'09 Proceedings of the 28th IEEE conference on Military communications
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Scale time offset robust modulation, or STORM, is a novel modulation technique that essentially adds time scaling to transmitted reference spread spectrum. STORM transmit signals are created using a pair of relatively offset signals. These signals are called the base and offset signals. The base signal may be random noise, colored noise, a PN sequence, or even a QAM signal. The offset signal is created from a copy of the base signal that is offset in time, time scale, phase, and/or amplitude. Summing the offset and base signal produces the transmit waveform. The transmit waveform is demodulated by estimating the cross-correlation between the received signal and a time scaled version of the received signal. This novel signal design delivers interesting features. First, the detection is robust when the base and offset signals maintain relative coherence. Second, using fixed bandwidth the multi-path delay resolution may be varied by changing the scale parameter. The demodulator non-coherently stacks multipath energy without using the rake architecture or independently resolves mUlti-path depending on the scale parameter. Processing rates are time scale dependent and are typically orders of magnitude lower than a comparable bandwidth matched filter receiver when the scale parameter is known in advance.