Channel reuse with cognitive low interference signals

An apparatus comprising:

• a radio comprising a modulator, the modulator configurable to transmit in a channel of spectrum in accordance with a configurable modulation scheme;
• a controller for the radio, the controller adapted to, when the apparatus is operating:
• sense the presence of a primary signal in the channel, the primary signal being transmitted by a primary device of a user of a portion of the spectrum;
• responsive to sensing the primary signal, determine a primary modulation scheme for the primary signal, the primary modulation scheme comprising primary modulation symbols;
• use the primary modulation symbols to derive or select a secondary modulation scheme having secondary modulation symbols determined according to the primary modulation symbols to have a minimal correlation with the primary modulation symbols, wherein the determination of minimal correlation is made by computing individual correlations of respective pairs of modulation symbols, each pair including a primary modulation symbol and a secondary modulation symbol, wherein the determination is made such that a secondary signal carrying data encoded with the secondary modulation scheme is received by primary devices communicating via the primary signal;
• and
• configure the radio to communicate secondary signals with the selected secondary modulation scheme, the communicating the secondary signals comprising exchanging data with another apparatus, the secondary signals carrying the data exchanged between the apparatus and the other apparatus.

An apparatus having encoded thereon computer-executable instructions that, when executed by a computer, cause the computer to carry out a method of operating a radio, the radio being adapted to be configured to operate in accordance with a plurality of encoding schemes, the plurality of encoding schemes comprising a first encoding scheme and a second encoding scheme, each encoding scheme corresponding to a respective constellation mapping a respective plurality of encoding scheme symbols to respective signal parameters, the method comprising:

• defining a derived encoding scheme for a secondary signal, the derived encoding scheme comprising symbols individually selected from a pool of candidate symbols for encoding data during data communication between devices, wherein the symbols of the derived encoding scheme are selected from the pool of candidate symbols by evaluating correlations of features of the candidate symbols in different subsets of the candidate symbols with features of primary symbols to select a subset of the candidate symbols such that features of the symbols in the derived encoding scheme are determined to have a collective minima of correlation with features of the primary symbols, the derived encoding scheme including a symbol from the first encoding scheme and including a symbol from the second encoding scheme;
• and
• exchanging data with a device by transmitting the data encoded with the derived encoding scheme by changing the configuration of the radio to operate in accordance with the at least two of the plurality of encoding schemes as the information is being communicated.