RECEIVER FOR USE IN A CODE SHIFT KEYING SPREAD SPECTRUM COMMUNICATIONS SYSTEM

摘要

A chirp spread spectrum receiver for use in a communication system that utilizes a modulation technique referred to as code shift keying (CSK). Code shift keying modulation transmits data in the form of circularly rotated chirp spreading waveforms. The data is conveyed in the amount of rotation applied to the chirp before it is transmitted. While tracking, the receiver decodes the received symbols yielding the original transmitted data. The input frequency range of the receiver is divided into one or more frequency bands whereby the receive signal is filtered, digitized and split into I and Q data streams for each frequency band. Both I and Q data streams are sampled and correlated with an adaptive template. The template in the receiver is dynamically adapted to varying conditions of the channel at each sample time using a template adaptation function.