Posted: July 9, 2014
Pilot Symbol Assisted Modulation is a wireless communications method for reducing the effects of a fading signal. By periodically inserting known ‘pilot’ symbols into a transmitter’s data stream, a receiver is able to derive an estimation of a fading channel’s amplitude and phase reference. This channel gain estimate allows the receiver to compensate for fading, therefore providing improved bit error rate performance and signal-to-noise ratio (SNR).
This technology is an optimized PSAM method for wireless receivers. Unlike conventional receivers, the novel “iPSAM” (i = iCORE) can provide gains of several dB’s in effective SNR by taking advantage of the optical line of sight component (Rician Channel). PSAM methods for the scattered, out-of phase optical components (Rayleigh channel) are virtually optimal already. As a result, the only significant component of the wireless channel left unexploited is the Rician component. Also, wireless cell sites are becoming smaller and smaller, therefore channel gain available from the line of sight component is becoming increasingly significant.
- Greatest benefits of iPSAM relative to PSAM are realized at small values of SNR. Therefore, as a channel begins to fade, gain from the Rician component is observed, and the improvement in modulation is seen where it is needed most (i.e. when a channel is fading).
- Invention is incorporated into the receiver only. Therefore, no modifications are required to the existing transmitter for the gains to be realized.
All manufacturers of digital modulation receivers for wireless digital communications. (e.g. Global System for Mobile communications (GSM) and Code Division Multiple Access (CDMA) receivers for cellphones; satellite networks, etc.).