Direct over-sampled pulse shaping circuit with flip flops and LUT

摘要

Example embodiments of systems and methods of direct oversampled low PAR pulse shaping encapsulating DSSS spreading are disclosed herein. Pulse-shaping of a DSSS spread data symbol stream results in a small number of waveform patterns to choose from for any data-symbol window. Low complexity programmable look-up table (LUT) based direct pulse shaping may be implemented, while only needing to compute a negation function. The chosen pulse shape may generate a low PAR for the baseband signal, allowing for a reduction in the saturation power of the power amplifier, thereby reducing the overall transmitter power consumption.

主权项

1. A system comprising:
a pulse shaper configured to receive a modulated data symbol stream and to apply direct over-sampled pulse shaping encapsulating Direct Sequence Spread Spectrum (DSSS) spreading, using a lookup table (LUT), to the data symbol stream to produce an oversampled baseband signal at a desired sampling rate, the pulse shaper including a plurality of flip flops configured to access the LUT, a first flip flop of the plurality of flip flops configured to access the LUT corresponding to a next data symbol of a three symbol sequence of the data symbol stream, a second flip flop of the plurality of flip flops configured to access the LUT corresponding to a previous data symbol of a three symbol sequence of the data symbol stream, and a third flip flop of the plurality of flip flops configured to access the LUT for a current data symbol of a three symbol sequence of the data symbol stream and to select the output of the LUT or the negative of the output of the LUT; and a transmitter configured to transmit the oversampled baseband signal.