Inverse signal transformation

• US 9,077,315 B2
• Filed: 12/12/2011
• Issued: 07/07/2015
• Est. Priority Date: 06/25/2003
• Status: Expired due to Fees

• Current Assignee: John W. Bogdan
• Original Assignee: John W. Bogdan
• Inventors: Bogdan, John W.
• Primary Examiner(s): Corrielus, Jean B
• Application Number:
  US13/323,820
• Publication Number:
  US 20120307923A1
• Time in Patent Office: 1,303 Days
• Field of Search: 375/340, 375/346, 375/285
• US Class Current: 1/1
• CPC Class Codes: H03H 17/0251 Comb filters
• CPC Class Codes: H03H 17/04 Recursive filters
• CPC Class Codes: H04L 25/0398 Restoration of channel reciprocity
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2695 with channel estimation, e.g. determination of delay spread, derivative or peak tracking channel estimation H04L25/0202

Abstract

This application presents a direct data recovery from subspaces or parameters subranges of a received OFDM signal pre-identified as corresponding to specific data symbols, by applying inverse signal transformation (IST) reversing deterministic and random distortions introduced by a transmission channel. The direct data recovery can eliminate an intermediate recovery of signal transmitted originally from the received OFDM signal and reduce processing errors, power consumption and computing resources required by such intermediate recovery in conventional receivers.

Claims

1. A method for data recovery using subspaces of preprocessed signals (DR SPS) wherein said preprocessed signals are outputted by a transmission system including a coding circuit for orthogonal frequency division multiplexing (OFDM), a transmission link coupled to said coding circuit and a preprocessor coupled to said transmission link, wherein said coding circuit encodes transmitted data into a transmitted OFDM signal comprising tones or sub-bands, said transmission link introduces deterministic or random distortions to said transmitted OFDM signal and said preprocessor transforms a received OFDM signal into said preprocessed signals derived as representing said tones or sub-bands;

wherein the DR SPS method comprises;

deriving an inverse transformation, reversing a transfer function of the transmission system, defined as a relation between the transmitted data and the subspaces derived as corresponding to the transmitted data;

comparing, using a real time processor, consecutive elements of intervals of the derived preprocessed signals with consecutive elements of reference frames defining the derived subspaces, wherein the intervals and the reference frames correspond to half-cycles or cycles of the tones or sub-bands represented by the derived preprocessed signals;

using results of the comparison for identifying the derived subspaces which the intervals belong to;

applying the inverse transformation to the identified subspaces in order to recover the transmitted data corresponding to the identified subspaces.

2. A DR SPS method as claimed in claim 1, wherein the DR SPS method comprises using a synchronous circular processor (SCP) for a real time processing of said received OFDM signal;

wherein the SCP comprises;

processing stages which are sequentially connected and fed with consecutive samples derived from the received OFDM signal;

wherein the processing stages comprise consecutive circular segments designated for storing or processing of the consecutive samples derived from the received OFDM signal;

wherein the storing or processing of the consecutive samples within the processing stages is driven by circular clocks applied periodically to the consecutive circular segments contained in the processing stages, in accordance to indexes circulating within numbers of the consecutive circular segments contained in the processing stages;

wherein some of the consecutive circular segments contained in each one of the processing stages are loaded with next consecutive samples or data,

at a time instant when other of the consecutive circular segments contained in the each one of the processing stages are supplying samples or data to a next one of said processing stages or an external circuit.

3. A DR SPS method as claimed in claim 1, wherein the DR SPS method comprises using a synchronous sequential processor (SSP) for a real time processing of said received OFDM signal and a programmable control unit (PCU) for a background processing;

wherein;

the PCU is used for the derivation of the inverse transformation based on theoretical models of the transmission system or an analysis of samples derived from the received OFDM signal and supplied by a waveform screening and capturing circuit (WFSC);

the PCU is used for controlling operations of the SSP wherein the SSP comprises sequentially connected processing stages driven with clocks synchronous to frames of the received OFDM signal and fed with the samples derived from the received OFDM signal.

4. A method for data recovery using parameters and subspaces of preprocessed signals (DR PSPS) wherein said preprocessed signals are produced by a transmission system which includes a coding circuit for orthogonal frequency division multiplexing (OFDM), a transmission link coupled to said coding circuit and a preprocessor coupled to said transmission link, wherein said coding circuit encodes transmitted data into a transmitted OFDM signal comprising tones or sub-bands, said transmission link introduces deterministic or random distortions to said transmitted OFDM signal and said preprocessor transforms a received OFDM signal into said preprocessed signals derived as representing said tones or sub-bands;

wherein the DR PSPS method comprises;

deriving an inverse transformation, reversing a transfer function of the transmission system, defined as a relation between the transmitted data and the subspaces derived as corresponding to the transmitted data;

processing the derived preprocessed signals in order to produce the parameters enabling selection of reference frames corresponding to the derived preprocessed signals, wherein the reference frames define the derived subspaces;

using the produced parameters for the selection of the corresponding reference frames;

comparing, using a real time processor, consecutive elements of intervals of the derived preprocessed signals with consecutive elements of the selected reference frames;

using results of the comparison for identifying the derived subspaces which the intervals belong to;

applying the inverse transformation to the identified subspaces in order to recover the transmitted data corresponding to the identified subspaces.

5. A DR PSPS method as claimed in claim 4, wherein the DR PSPS method comprises using a synchronous circular processor (SCP) for a real time processing of said received OFDM signal;

wherein the SCP comprises;

processing stages which are sequentially connected and fed with consecutive samples derived from the received OFDM signal;

wherein the processing stages comprise consecutive circular segments designated for storing or processing of the consecutive samples derived from the received OFDM signal;

wherein the storing or processing of the consecutive samples within the processing stages is driven by circular clocks applied periodically to the consecutive circular segments contained in the processing stages, in accordance to indexes circulating within numbers of the consecutive circular segments contained in the processing stages;

wherein some of the consecutive circular segments contained in each one of the processing stages are loaded with next consecutive samples or data,

at a time instant when other of the consecutive circular segments contained in the each one of the processing stages are supplying samples or data to a next one of said processing stages or an external circuit.

6. A DR PSPS method as claimed in claim 4, wherein the DR PSPS method comprises using a synchronous sequential processor (SSP) for a real time processing of said received OFDM signal and a programmable control unit (PCU) for a background processing;

wherein;

the PCU is used for the derivation of the inverse transformation based on theoretical models of the transmission system or an analysis of samples derived from the received OFDM signal and supplied by a waveform screening and capturing circuit (WFSC);

the PCU is used for controlling operations of the SSP wherein the SSP comprises sequentially connected processing stages driven with clocks synchronous to frames of the received OFDM signal and fed with the samples derived from the received OFDM signal.

7. A method for data recovery using subranges of parameters of preprocessed signals (DR SPPS) wherein said parameters are produced by a transmission system which includes a coding circuit using orthogonal frequency division multiplexing (OFDM), a transmission link coupled to said coding circuit, a preprocessor coupled to said transmission link and a processor coupled to said preprocessor, wherein said coding circuit encodes transmitted data into a transmitted OFDM signal comprising tones or sub-bands, said transmission link transforms said transmitted OFDM signal into a received OFDM signal affected by deterministic or random distortions, said preprocessor produces said preprocessed signals representing said tones or sub-bands;

wherein the DR SPPS method comprises the steps of;

deriving an inverse transformation, reversing a transfer function of the transmission system, defined as a relation between the transmitted data and the subranges derived as corresponding to the transmitted data;

deriving, using the processor, the parameters corresponding to amplitudes or phases of half cycles or cycles of the tones or sub-bands;

comparing the derived parameters with references defining the derived subranges;

using results of the comparison for identifying the derived subranges comprising the derived parameters;

applying the inverse transformation to the identified subranges in order to recover the transmitted data corresponding to the identified subranges.

8. A DR SPPS method as claimed in claim 7, wherein the DR SPPS method comprises using a synchronous circular processor (SCP) for a real time processing of said received OFDM signal;

wherein the SCP comprises;

processing stages which are sequentially connected and fed with consecutive samples derived from the received OFDM signal;

wherein the processing stages comprise consecutive circular segments designated for storing or processing of the consecutive samples derived from the received OFDM signal;

wherein the storing or processing of the consecutive samples within the processing stages is driven by circular clocks applied periodically to the consecutive circular segments contained in the processing stages, in accordance to indexes circulating within numbers of the consecutive circular segments contained in the processing stages;

wherein some of the consecutive circular segments contained in each one of the processing stages are loaded with next consecutive samples or data,

at a time instant when other of the consecutive circular segments contained in the each one of the processing stages are supplying samples or data to a next one of said processing stages or an external circuit.

9. A DR SPPS method as claimed in claim 7, wherein the DR SPPS method comprises using a synchronous sequential processor (SSP) for a real time processing of said received OFDM signal and a programmable control unit (PCU) for a background processing;

wherein;

the PCU is used for the derivation of the inverse transformation based on theoretical models of the transmission system or an analysis of samples derived from the received OFDM signal and supplied by a waveform screening and capturing circuit (WFSC);

the PCU is used for controlling operations of the SSP wherein the SSP comprises sequentially connected processing stages driven with clocks synchronous to frames of the received OFDM signal and fed with the samples derived from the received OFDM signal.

10. A method for data recovery using subranges of parameters of preprocessed signals (DR SPPS) wherein said parameters of said preprocessed signals are produced by a transmission system comprising a coding circuit using orthogonal frequency division multiplexing (OFDM), a transmission link coupled to said coding circuit, a preprocessor coupled to said transmission link and a processor coupled to said preprocessor, wherein said coding circuit encodes data symbols into a transmitted OFDM signal comprising tones or sub-bands, said transmission link transforms said transmitted OFDM signal into a received OFDM signal affected by deterministic or random distortions, said preprocessor produces said preprocessed signals representing said tones or sub-bands;

wherein the DR SPPS method comprises the steps of;

deriving an inverse transformation reversing a transfer function of the transmission system, defined as a relation between the data symbols and the subranges derived as corresponding to the data symbols;

deriving, using the processor, the parameters corresponding to amplitudes or phases of half-cycles or cycles of the tones or sub-bands;

applying the inverse transformation for recovering the data symbols from the derived subranges which comprise the derived parameters, by using the derived parameters for direct addressing of a content addressed memory preloaded with the data symbols.

11. A DR SPPS method as claimed in claim 10, wherein the DR SPPS method comprises using a synchronous circular processor (SCP) for a real time processing of said received OFDM signal;

wherein the SCP comprises;

processing stages which are sequentially connected and fed with consecutive samples derived from the received OFDM signal;

wherein the processing stages comprise consecutive circular segments designated for storing or processing of the consecutive samples derived from the received OFDM signal;

wherein the storing or processing of the consecutive samples within the processing stages is driven by circular clocks applied periodically to the consecutive circular segments contained in the processing stages, in accordance to indexes circulating within numbers of the consecutive circular segments contained in the processing stages;

wherein some of the consecutive circular segments contained in each one of the processing stages are loaded with next consecutive samples or data,

at a time instant when other of the consecutive circular segments contained in the each one of the processing stages are supplying samples or data to a next one of said processing stages or an external circuit.

12. A DR SPPS method as claimed in claim 10, wherein the DR SPPS method comprises using a synchronous sequential processor (SSP) for a real time processing of said received OFDM signal and a programmable control unit (PCU) for a background processing;

wherein;

the PCU is used for the derivation of the inverse transformation based on theoretical models of the transmission system or an analysis of samples derived from the received OFDM signal and supplied by a waveform screening and capturing circuit (WFSC);

the PCU is used for controlling operations of the SSP wherein the SSP comprises sequentially connected processing stages driven with clocks synchronous to frames of the received OFDM signal and fed with the samples derived from the received OFDM signal.