Patent ID: 7391819

Claim:
A method for implementation of Quadrature Parallel-Layered Modulation (QLM) for communications over the same frequency bandwidth of a carrier frequency, said method comprising the steps: generating a first communications signal over the frequency bandwidth at the carrier frequency for the first channel by modulating a first stream of data symbols with a waveform at a 1/T s symbol rate wherein “T s ” is the time interval between contiguous symbols, generating a second communications signal over the same frequency bandwidth at the same carrier frequency for a second channel by modulating a second stream of data symbols with the same waveform at the same symbol rate as the first stream of data symbols and with a time offset ΔT s equal to ΔT s =T s /n p wherein “n p ” is the number of QLM channels in said frequency bandwidth, for any additional channels, continuing generation of communication signals over the same frequency bandwidth at the same carrier frequency by modulating additional streams of data symbols with the same waveform at the same data symbol rate as the first and second streams of data symbols, with time offsets increasing in each communication signal in increments of ΔT s =T s /n p until the n p signals are generated for n p QLM channels, transmitting and receiving said communications signals over a QLM communications link consisting of the n p QLM channels, recovering data symbols of the communications signals in a receiver using a demodulation algorithm, and combining said algorithm with error correction decoding to recover the transmitted information; whereby time offsets have been used as a differentiating parameter to enable QLM parallel channels of communications over the same frequency bandwidth at the same carrier frequency with a data symbol rate above the Nyquist rate, to be demodulated, wherein the communication signals have the following properties: maximum capacity “C” in bits/second is defined by equation C =max{ n p B log 2 (1+( S/N )/ n p ^2)} wherein the maximum “max” is with respect to n p , “log 2 ” is the logarithm to the base 2, “B” is the frequency bandwidth in Hz, and “S/N” is the ratio signal-to-noise over “B”, maximum number of bits “b” per symbol interval T s =1/B is defined by equation max{ b }=max{ n p (1+( S/N )/ n p ^2)}, maximum communications efficiency “η” in Bits/second/Hz is defined by equation max(η}=max{b}, minimum signal-to-noise ratio per bit “E b /N o ” is defined by equation min{ E b /N o }=min{[ n p ^2 /b][ 2^ b}/n p −1]} wherein “E b ” is the energy per bit, “N o ” is the power spectral density of the noise, and the minimum “min” is the minimum with respect to n p , and wherein these performance bounds apply to communications receiver demodulation performance of a QLM communications link consisting of n p QLM channels.