# US 2010/0166102 A1 · Windowed orthogonal division multiplexing for spectrum agile radios > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166102 A1 - Document ID: US20100166102A1 - Status: Published application - Kind: A1 - Application number: 12/095,628 - Filed: 2006-11-30 - Published: 2010-07-01 - Earliest claimed: 2005-11-30 - Inventors: Seyed-Alireza Seyedi-Esfahani - Web page: https://patentgrep.com/patent/US20100166102A1 ## CPC - H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH} - H04L 27/2628: {Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators (H04L27/2634 takes precedence)} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method of transmitting data includes modulating data onto a plurality of frequency carriers to produce a plurality of mutually orthogonal modulated frequency signals. The mutually orthogonal modulated frequency signals are then combined into an orthogonal frequency division multiplex signal, which in turn is windowed by a transmission windowing function to produce a windowed orthogonal frequency division multiplex signal. The windowed orthogonal frequency division multiplex signal is transmitted. The windowed orthogonal frequency division multiplex signal includes a first set of the frequency carriers uniformly spaced apart from each other in frequency by a spacing Δf, and a second set of the frequency carriers from each other in frequency by the same spacing Δf, and there is a notch of at least 2Δf between the first set of frequency carriers and the second set of frequency carriers. ## Claims ### Claim 1 A method of transmitting data, comprising: providing P frequency carriers uniformly spaced apart across a frequency band; determining that an incumbent transmission is present in a portion of the frequency band spanning X of the P frequency carriers; turning off at least M of the frequency carriers spanning the portion of the frequency band where the incumbent transmission is present, where M≧X, and modulating data only onto a remaining N≦P−M frequency carriers to produce N mutually orthogonal modulated frequency carriers; performing an inverse fast Fourier transform on the N mutually orthogonal modulated frequency carriers to produce N OFDM transmission symbols; windowing the N OFDM transmission symbols with a window function WTX(n) and performing a parallel-to-serial conversion of the N OFDM transmission symbols to produce a windowed orthogonal frequency division multiplex signal; and transmitting a windowed orthogonal frequency division multiplex signal, wherein the M turned-off frequency carriers are consecutively arranged within the frequency band so as to create a notch in the frequency spectrum of the windowed orthogonal frequency division multiplex signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the parallel-to-serial conversion of the N OFDM transmission symbols is performed before windowing the N OFDM transmission symbols. ### Claim 3 (depends on 1) The method of claim 1, wherein the windowing of the N OFDM transmission symbols is performed before the parallel-to-serial conversion of the N OFDM transmission symbols. ### Claim 4 (depends on 1) The method of claim 1, wherein modulating the data onto N frequency carriers comprises assigning each sample of the data into one of N IFFT bins, and wherein turning off the M frequency carriers comprises assigning data values of zero to each of M IFFT bins. ### Claim 5 (depends on 1) The method of claim 1, further comprising mapping the data to unmodulated symbols prior to modulating the data onto the N frequency carriers. ### Claim 6 (depends on 5) The method of claim 5, further comprising performing a serial-to-parallel conversion on the unmodulated symbols prior to modulating the data onto the N frequency carriers. ### Claim 7 (depends on 6) The method of claim 6, further comprising, prior to performing the serial-to-parallel conversion: modulating the data onto every Lth frequency carrier; not modulating any data onto the other frequency carriers; and turning off the other frequency carriers, where L is an integer greater than 1. ### Claim 8 (depends on 1) The method of claim 1, further comprising turning off a second group of R frequency carriers consecutively arranged within the frequency band to create a second notch in the frequency spectrum of the windowed orthogonal frequency division multiplex signal, where N≦P−M−R ### Claim 9 An orthogonal frequency division multiplex transmitter, comprising: a modulator (240, 410) adapted to provide P frequency carriers, to turn off M frequency carriers of the P frequency carriers, to receive data, and to modulate the data only onto a remaining, N≦P−M frequency carriers to produce N mutually orthogonal modulated frequency carriers; means (250, 440/450) for combining the N mutually orthogonal modulated frequency signals into an orthogonal frequency division multiplex signal; a transmission window (260, 460) adapted to apply a window function to the orthogonal frequency division multiplex signal to produce a windowed orthogonal frequency division multiplex signal; and a transmitter (270, 480) transmitting the windowed orthogonal frequency division multiplex signal, wherein the M turned-off frequency carriers are consecutively arranged within the frequency band so as to create a notch in the frequency spectrum of the windowed orthogonal frequency division multiplex signal. ### Claim 10 (depends on 9) The transmitter (400) of claim 9, wherein the means for combining the mutually orthogonal modulated frequency signals into an orthogonal frequency division multiplex signal comprises an inverse Fast Fourier transformer (IFFT) (440). ### Claim 11 (depends on 10) The transmitter (400) of claim 10, wherein the means for combining the mutually orthogonal modulated frequency signals into an orthogonal frequency division multiplex signal further comprises a parallel-to-serial converter (450) adapted to convert OFDM transmission symbols produced by the IFFT into the orthogonal frequency division multiplex signal. ### Claim 12 (depends on 9) The transmitter (400) of claim 9, further comprising a symbol mapper (410) adapted to map the data to unmodulated symbols prior to modulating the data onto the N frequency carriers. ### Claim 13 (depends on 12) The transmitter (400) of claim 12, further comprising a serial-to-parallel converter (430) adapted to convert the unmodulated symbols from a serial format to a parallel format prior to modulating the data onto the N frequency carriers. ### Claim 14 (depends on 13) The transmitter (400) of claim 13, further comprising an up-sampler (420) which, prior to performing the serial-to-parallel conversion modulates the data onto every Lth frequency carrier, does not modulating any data onto the other frequency carriers, and turns off the other frequency carriers, where L is an integer greater than 1. ### Claim 15 A method of transmitting data, comprising: modulating data onto a plurality of frequency carriers to produce a plurality of mutually orthogonal modulated frequency signals; combining the mutually orthogonal modulated frequency signals into an orthogonal frequency division multiplex signal; multiplying the orthogonal frequency division multiplex signal by a transmission windowing function to produce a windowed orthogonal frequency division multiplex signal; and transmitting the windowed orthogonal frequency division multiplex signal, wherein the windowed orthogonal frequency division multiplex signal includes a first set of the frequency carriers uniformly spaced apart from each other in frequency by a spacing Δf, and a second set of the frequency carriers spaced apart from each other in frequency by the same spacing Δf, and there is a notch of at least 2Δf between the first set of frequency carriers and the second set of frequency carriers. ### Claim 16 (depends on 15) The method of claim 15, wherein modulating the data onto the plurality of frequency carriers comprises: assigning each sample of the data into one of a plurality of IFFT bins, and performing an IFFT on the data samples. ### Claim 17 (depends on 15) The method of claim 15, further comprising mapping the data to unmodulated symbols prior to modulating the data onto the plurality of frequency carriers. ### Claim 18 (depends on 17) The method of claim 17, further comprising performing a serial-to-parallel conversion on the unmodulated symbols prior to modulating the data onto the plurality of frequency carriers. ### Claim 19 (depends on 18) The method of claim 18, further comprising, prior to performing the serial-to-parallel conversion: modulating the data onto every Lth frequency carrier; not modulating any data onto the other frequency carriers; and turning off the other frequency carriers, where L is an integer greater than 1. ### Claim 20 (depends on 18) The method of claim 18, wherein the window function is a Chebyshev function.