Patent Application: US-76599004-A

Abstract:
a method and system for increasing the effective communications channel bandwidth beyond that of the constrained physical bandwidth of a given channel by orthogonal signal spectrum overlay comprising : decomposing the time - bandwidth product of a given symbol in a data stream transmitted through a given bandwidth , expanding the tbp in terms of overlaid orthogonal signals such as weber - hermite functions that constitute the eigensignals of the symbol . the complete data stream is multiplexed to produce a plurality of data channels , each of which is encoded on an orthogonal signal by quadrature amplitude modulation . the overlay of these signals constitutes the osso symbol . the osso symbols are transmitted in quadrature format and are the result of the addition of orthogonal signals , each of which constitutes a separate overlaid communication channel , occupying the same physical bandwidth .

Description:
wh signals ( fig1 ) are orthogonal in both the time and frequency domains when overlaid within a transmitted symbol — the osso symbol — and occupy no more physical bandwidth than that required for the wh signal of the largest time - bandwidth product . the number of wh signals that can occupy a given osso symbol is set by the time - bandwidth product of the osso symbol . the wh signals overlaid within the symbol are orthogonal in both the time and frequency domains , and the orthogonality of these wh signals does not arise from sub - band displacement in time as in the case of walsh functions , in frequency , as in the case of wavelets or ofdm ( see fig2 for comparison ). the orthogonality of wh signals is due to their correlation properties when precisely overlaid . the summation of the wh signals constitutes the envelope of an osso symbol which is transmitted in both i and q form ( fig3 ). the wh signals can be generated analytically , so the osso symbol can be generated digitally ( fig4 ). each of the wh signals within an osso symbol is modulated , e . g ., qam - modulated , in i and q ( fig5 , 6 and 7 ). examples of cross - correlations of signal templates with osso symbols in the time and frequency domains are shown in fig8 a and b . these show cross - correlations of the wh 0 or a wh 9 signal template with a 10 - osso or 9 - osso symbol in which the wh 0 or wh 9 signal is either present or absent . when the relevant signal is present , there is a finite amplitude at the zeroth time position . when the relevant signal is absent , the amplitude at the zero time position is zero . in practice , signal recapture can utilize the inner products of signal templates with osso symbols . to illustrate the fundamental nature of the wh signals with respect to the time - bandwidth product overlay within the osso symbol , outer products of signal templates with osso symbols are shown in fig9 a and b . these show the outer product of the wh 0 or wh 9 signal template with a 10 - osso or 9 - osso symbol in which the wh 0 or wh 9 signal is either present or absent . when the relevant signal is present , there is a distinctively different surface pattern than when the signal is absent . each wh signal within an osso symbol is independently modulated . as illustration , fig1 a and b show how the signals wh 0 , wh 1 , wh 2 and wh 3 are independently 16 - qam modulated . the general methods for osso transmission and reception at a point of utilization are shown in fig1 a and b . ( these are schematic designs for purposes of illustration and in practice operations that are made explicit in these designs can be performed by dedicated and programmable electronic devices such as fpgas and dsps .) there is an initial serial - to - parallel conversion of the data stream into words that are assigned to specific wh signals ( fig1 a ). the amplitude of each wh signal in i and q form assigns a word of information to a constellation . thus each wh signal forms a different information channel that represents and conveys a different word of information . the different wh signals — in the case illustrated in fig1 a there are four wh signals — are summed in i and q to form the osso symbol envelope . this envelope then is d - to - a converted and modulates the carrier in i and q . thus the carrier is only of consequence to the data encoding in providing an i and q phase reference . the reception follows the transmission procedure in reverse ( fig1 b ) but with the additional step of correlative recapture of the separate wh signals from the osso symbol . before that step , the carrier is removed in i and q form , thus permitting the recapture of the osso envelope in i and q form . after a - to - d conversion of these envelopes in i and q , both are correlated in parallel against templates of the wh signals as previously described , of which in this particular example there are four . the output of each correlation operation is a single amplitude value that permits the recapture of the individual channel qam constellations , defining the individual words of information . finally , the serial data stream is recaptured by a parallel - to - serial operation on these words . these methods described above address the transmission and reception of osso symbols . the symbols themselves can be positioned in time in frames according to well - known methods using ( time - displacement positioning ) orthogonal codes utilized in , e . g ., tdma and cdma schemes ( fig1 ). as the carrier is relevant only in providing i and q forms , osso can be used as a modulation on any or all separate individual carriers that are sub - bands of a broader bandwidth channel . the invention can be instantiated in a variety of ways to those familiar in the art of electronics — both in hardware , e . g ., fpgas , dsps , a - to - d and d - to - a converters , serial - to - parallel and parallel - to - serial converters , los of any frequency , or a combination of hardware and software . the invention can be instantiated for wired , fiber , cable , wireless , optical , ir or rf communications systems , and at any signal frequency or for any channel bandwidth . the invention can also be instantiated with signals other than wh signals , e . g ., derivatives of raised cosine pulses , or by all signals orthogonal in direct overlay ( as opposed to by means of displacement ). the method and apparatus constructed according to the method have applications in increasing the spectral efficiency of communications channels limited by bandwidth restrictions . the method of the invention applies to any method of communications , whether wired , fiber , cable , wireless , optical , ir or rf communications , and at any signal frequency or for any channel bandwidth . the invention increases spectral efficiency by increasing the effective bandwidth without increasing the physical bandwidth . in communications channels in general — whether wired , fiber , cable , wireless , optical , ir or rf communications , and at any signal frequency or for any channel bandwidth , the invention features : methods for increasing an effective communications channel bandwidth beyond that of the constrained physical bandwidth of that channel . methods for greatly increasing the spectral efficiency ( bits / sec / hz ) of a communications channel by increasing the effective bandwidth . methods that employ orthogonal signal spectrum overlay ( osso ) in a communications channel . methods that employ either weber - hermite functions / signals or derivatives of raised cosine pulses or similar or related functions / signals to achieve osso . methods that employ overlaid orthogonal signals to achieve osso . while the invention has been described in relation to preferred embodiments of the invention , it will be appreciated that other embodiments , adaptations and modifications of the invention will be apparent to those skilled in the art . barrett , t . w ., the information content of an electromagnetic field with relevance to sensory processing of information . t . i . t . j . life sciences , 1 , 129 - 135 , 1971 . barrett , t . w ., on vibrating strings and information theory . j . sound & amp ; 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