US9270512B2ActiveUtilityA1

Nonlinearity compensation for reception of OFDM signals

78
Assignee: MAGNACOM LTDPriority: Jun 6, 2014Filed: Nov 14, 2014Granted: Feb 23, 2016
Est. expiryJun 6, 2034(~7.9 yrs left)· nominal 20-yr term from priority
Inventors:Amir EliazIlan Reuven
H04L 1/20H04W 16/14H04L 27/2647H04B 1/10H04L 25/03305H04L 25/03821H04B 17/3912H04L 27/366H04J 11/0023H04B 17/391H04L 27/3863
78
PatentIndex Score
3
Cited by
321
References
32
Claims

Abstract

An electronic receiver may comprise nonlinear distortion modeling circuitry, interference estimation circuitry, and sequence estimation circuitry. The receiver may receive an orthogonal frequency division multiplexing (OFDM) symbol in the form of an electromagnetic signal. The nonlinear distortion modeling circuitry may generate a nonlinear distortion model that models nonlinear distortion introduced to the received electromagnetic signal en route to the sequence estimation circuitry. The interference estimation circuitry may estimate inter-subcarrier interference present in the received OFDM symbol based on the generated nonlinear distortion model. The estimating of the inter-subcarrier interference may comprise applying the nonlinear distortion model to one or more candidate vectors generated by the sequence estimation circuitry. The sequence estimation circuitry may sequentially process a plurality of received virtual subcarrier values of the OFDM symbol using the estimated inter-subcarrier interference.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A receiver comprising:
 an analog front end circuit operable to receive a nonlinearly distorted orthogonal frequency division multiplexed (OFDM) symbol that is a result of a plurality of symbols transmitted on a plurality of subcarriers; 
 nonlinear distortion modeling circuitry operable to generate a model of nonlinear distortion introduced to said OFDM symbol by a transmitter, wherein:
 a result of said nonlinear distortion is inter-subcarrier interference in said received OFDM symbol; and 
 said model of said nonlinear distortion is a digital clipping model; and circuitry operable to: 
 iteratively calculate metrics based on said received OFDM symbol and said model of nonlinear distortion; and 
 determine values of said symbols based on said metrics. 
 
 
     
     
       2. The receiver of  claim 1 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a mathematical and/or logical expression. 
     
     
       3. The receiver of  claim 1 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a look-up table. 
     
     
       4. The receiver of  claim 3 , wherein said look-up table is indexed based on a transmitted signal power parameter. 
     
     
       5. The receiver of  claim 1 , wherein said generation of said model is based on control information received from a transmitter from which said OFDM symbol originated. 
     
     
       6. The receiver of  claim 5 , wherein said control information comprises an identification of a type of nonlinear distortion model best suited for use with said OFDM symbol. 
     
     
       7. The receiver of  claim 5 , wherein said control information comprises initial values for parameters of said model of said nonlinear distortion model. 
     
     
       8. The receiver of  claim 5 , wherein said control information is received during handshaking with said transmitter. 
     
     
       9. The receiver of  claim 5 , wherein said control information is received in a preamble of said OFDM symbol. 
     
     
       10. A method comprising:
 in a receiver:
 receiving, by an analog front end circuit, a nonlinearly distorted orthogonal frequency division multiplexed (OFDM) symbol that is a result of a plurality of symbols transmitted on a plurality of subcarriers; 
 generating, by nonlinear distortion modeling circuitry, a model of nonlinear distortion introduced to said OFDM symbol by a transmitter, wherein:
 a result of said nonlinear distortion is inter-subcarrier interference in said received OFDM symbol; and 
 said model of said nonlinear distortion is a digital clipping model; 
 
 iteratively calculating, by circuitry of said receiver, metrics based on said received OFDM symbol and said model of nonlinear distortion; and 
 determining, by circuitry of said receiver, values of said symbols based on said metrics. 
 
 
     
     
       11. The method of  claim 10 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a mathematical and/or logical expression. 
     
     
       12. The method of  claim 10 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a look-up table. 
     
     
       13. The method of  claim 12 , wherein said look-up table is indexed based on a transmitted signal power parameter. 
     
     
       14. The method of  claim 10 , wherein said generating said model is based on control information received from a transmitter from which said OFDM symbol originated. 
     
     
       15. The method of  claim 14 , wherein said control information comprises an identification of a type of nonlinear distortion model best suited for use with said OFDM symbol. 
     
     
       16. The method of  claim 14 , wherein said control information comprises initial values for parameters of said model of said nonlinear distortion model. 
     
     
       17. The method of  claim 14 , comprising receiving said control information during handshaking with said transmitter. 
     
     
       18. The method of  claim 14 , comprising receiving said control information in a preamble of said OFDM symbol. 
     
     
       19. A receiver comprising:
 an analog front end circuit operable to receive a nonlinearly distorted orthogonal frequency division multiplexed (OFDM) symbol that is a result of a plurality of symbols transmitted on a plurality of subcarriers; 
 nonlinear distortion modeling circuitry operable to generate a model of nonlinear distortion introduced to said OFDM symbol by a transmitter, wherein:
 a result of said nonlinear distortion is inter-subcarrier interference in said received OFDM symbol; 
 said model of said nonlinear distortion is stored in memory of said receiver as a look-up table; and 
 said look-up table is indexed based on a transmitted signal power parameter; and 
 
 circuitry operable to:
 iteratively calculate metrics based on said received OFDM symbol and said model of nonlinear distortion; and 
 determine values of said symbols based on said metrics. 
 
 
     
     
       20. The receiver of  claim 19 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a mathematical and/or logical expression. 
     
     
       21. The receiver of  claim 19 , wherein said generation of said model is based on control information received from a transmitter from which said OFDM symbol originated. 
     
     
       22. The receiver of  claim 21 , wherein said control information comprises an identification of a type of nonlinear distortion model best suited for use with said OFDM symbol. 
     
     
       23. The receiver of  claim 21 , wherein said control information comprises initial values for parameters of said model of said nonlinear distortion model. 
     
     
       24. The receiver of  claim 21 , wherein said control information is received during handshaking with said transmitter. 
     
     
       25. The receiver of  claim 21 , wherein said control information is received in a preamble of said OFDM symbol. 
     
     
       26. A method comprising:
 in a receiver:
 receiving, by an analog front end circuit, a nonlinearly distorted orthogonal frequency division multiplexed (OFDM) symbol that is a result of a plurality of symbols transmitted on a plurality of subcarriers; 
 generating, by nonlinear distortion modeling circuitry, a model of nonlinear distortion introduced to said OFDM symbol by a transmitter, wherein:
 a result of said nonlinear distortion is inter-subcarrier interference in said received OFDM symbol; 
 said model of said nonlinear distortion is stored in memory of said receiver as a look-up table; and 
 said look-up table is indexed based on a transmitted signal power parameter; and 
 
 iteratively calculating, by circuitry of said receiver, metrics based on said received OFDM symbol and said model of nonlinear distortion; and 
 determining, by circuitry of said receiver, values of said symbols based on said metrics. 
 
 
     
     
       27. The method of  claim 26 , wherein said model of said nonlinear distortion is stored in memory of said receiver as a mathematical and/or logical expression. 
     
     
       28. The method of  claim 26 , wherein said generating said model is based on control information received from a transmitter from which said OFDM symbol originated. 
     
     
       29. The method of  claim 28 , wherein said control information comprises an identification of a type of nonlinear distortion model best suited for use with said OFDM symbol. 
     
     
       30. The method of  claim 28 , wherein said control information comprises initial values for parameters of said model of said nonlinear distortion model. 
     
     
       31. The method of  claim 28 , comprising receiving said control information during handshaking with said transmitter. 
     
     
       32. The method of  claim 28 , comprising receiving said control information in a preamble of said OFDM symbol.

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