A communication method and system for communication utilizing modulation of digital signals, such as by targets and/or by use of low-complexity tags is presented. Targets may include any device or object that may alter signals, and tags can include a device with the ability to reflect and/or alter the properties of the signals and, in doing so, impose specific modulations on or alterations of such signals. Modulations can be sensed or detected using a receiver or receivers implementing processing algorithms derived from passive radar detection operations or other processes
