(54) BLOCKAGE MITIGATION TECHNIQUES FOR INFORMATION TRANSMISSION
(76) Inventor: William W. Wu, 6 Spruce Tree Ct., Bethesda, MD (US) 20814-1625
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 197 days.
U.S. CI 370/229; 714/47; 714/748
Field of Classification Search 370/216,
370/229,311; 455/45,67.3; 714/48,790, 714/490, 748, 789; 375/224 See application file for complete search history.
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Transmission channel monitoring, detection, classification, and adaptation provide solutions to severe information blockage problems during transmission. Channel monitoring is achieved through two types of detection and retransmission strategies. Channel detection is accomplished by means of counting the number of negative acknowledgements, which classifies the channel degradation level and determines which alternatives to be adapted in order to combat specific blockage phenomenon. Blockage level is first translated into and related to transmission link parameters in terms of total carrier power to noise ratios, from which the methods of bit rate reduction, modem density increasing, and higher encoding rate are brought forth. A blockage identifier and the optimal smearing technique are used. Frequency-diversity and space-diversity, a method for combating complete blockage and an adaptive programmable channel equalization technique independent of channel characteristics are described. A cascading technique is taught to improve significantly false- and miss-detection probabilities. Performance measures are established in terms of system efficiency and error probability for blockage mitigation with unequal terminal capabilities.
28 Claims, 6 Drawing Sheets