Presented herein are pilot-less noise estimation techniques that utilize a correlation between attributes of a received signal and the noise to generate signal-to-noise ratio estimate for the signal. Assets are verified through unique identification systems which provide for security even though the entity may remain anonymous and also provides for a networked portable transaction system with the identified assets. The non-systematic and non-linear PC-TCM described herein may be modified to support a wide variety of code rates and also a wide modulation types and 16 QAM among other modulation types). A lighting component is extracted from the background image and a lighting component included in the original image is eliminated using the extracted lighting component.