# US 8,149,931 B2 · Multi-carrier transmission process and system in a difficult environment with optimisation of emission power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,149,931 B2 - Document ID: US8149931B2 - Status: Granted - Kind: B2 - Application number: 11/999,467 - Filed: 2007-12-04 - Published: 2008-09-04 - Granted: 2012-04-03 - Earliest claimed: 2006-12-05 - Assignees: Sercel - Inventors: Jean-Eric Negre; Emmanuel Senechal; Luc Fety; Michel Terre - Web page: https://patentgrep.com/patent/US8149931B2 ## CPC - H04L 27/2614: {Peak power aspects} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterized in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10−q, then due to this process the probability will be 10−2q. ## Claims ### Claim 1 A data transmission process, from a first unit (1) to a second unit (2), the two units (1, 2) being in communication via a channel (11), the process comprising at least the following stages: digital analog conversion by means of a digital analog converter (8) of data to obtain an analog signal forming support of the data, amplification of said analog signal, prior to its emission via the channel (11) by means of an amplifier (9), characterised in that the process further comprises at least the following stages: completing at least two distinct scramblings (20, 21) of the data, such that there are at least two sets of scrambled data, determination of the inverse Fourier Transform of said at least two sets of scrambled data, determination of the dynamics in amplitude of each of said at least two sets of scrambled data after inverse Fourier Transform, selection (26) of one of the sets of scrambled data intended for emission among said inverse Fourier Transforms of the sets of scrambled data having a dynamic in amplitude compatible with the maximum permitted dynamics by the assembly formed by the digital analog converter (8) and the amplifier (9), wherein the inverse Fourier Transforms of said at least two sets of scrambled data are determined from real and imaginary parts of at least one complex inverse Fourier Transform (IFFTc, 25). ### Claim 2 (depends on 1) The transmission process as claimed in claim 1, characterised in that the dynamics in amplitude of said at least two sets of data are compatible with the maximum dynamics permitted by the assembly formed by the digital analog converter (8) and the amplifier (9), and in that any one of said at least two sets of scrambled data intended for emission is selected. ### Claim 3 (depends on 1) The transmission process as claimed in claim 1, characterised in that a single dynamic in amplitude of said at least two sets of data is compatible with the maximum dynamics permitted by the assembly formed by the digital analog converter (8) and the amplifier (9), and in that the single set of compatible scrambled data intended for emission is sent. ### Claim 4 (depends on 1) The transmission process as claimed in claim 1, characterised in that the dynamics in amplitude of said at least two sets of data are incompatible with the maximum dynamics permitted by the assembly formed by the digital analog converter and the amplifier, and in that the set of data among said at least two sets of data having the lowest dynamic intended for emission is selected. ### Claim 5 (depends on 1) The transmission process as claimed in claim 1, wherein if there are 2M scramblers, M.gtoreq.1, then M modules of inverse Fourier transform are utilised. ### Claim 6 (depends on 1, 2, 3, 4, 5) The transmission process as claimed in claim 1, 2, 3, 4 or 5 further comprising a stage where a supplementary datum intended to indicate to the second unit (2) the scrambler utilised for emission is sent. ### Claim 7 (depends on 6) The transmission process as claimed in claim 6, characterised in that the datum corresponds to a binary code known in advance by the second unit (2), whereof the values identify the different scramblings not employed. ### Claim 8 (depends on 1) The transmission process as claimed in claim 1, wherein the two scramblings only are completed, and the supplementary datum corresponds to a bit whereof the values ‘0’ and ‘1’ identify respectively one and the other of these two scramblings. ### Claim 9 (depends on 8) The transmission process as claimed in claim 8, wherein the supplementary datum is sent according to modulation of type BPSK. ### Claim 10 (depends on 1) The transmission process as claimed in claim 1, wherein the data is sent over a plurality of carriers. ### Claim 11 (depends on 1) The transmission process as claimed in claim 1, wherein the supplementary datum for identifying the scrambling is sent to a carrier different to those used for the rest of the data. ### Claim 12 (depends on 1) The transmission process as claimed in claim 1, characterised in that the first unit (1) is situated at an altitude different to the second unit (2). ### Claim 13 (depends on 12) The transmission process as claimed in claim 12, characterised in that the first unit (1) is situated at a predetermined depth of an oil well and in that the second unit (2) is situated at the surface of said oil well. ### Claim 14 (depends on 12) The transmission process as claimed in claim 12, characterised in that the first unit and the second (2) are connected by a cable forming a distribution channel for the data. ### Claim 15 (depends on 14) The transmission process as claimed in claim 14 characterised in that the cable is a hepta-cable or a coaxial cable.