简介：Basedontheperiodicstructureofcodeworksoflinearblockcodes,anewideaoflength-varyingcodingdigitalcommunicationssystemisproposedtosavethechannel.Itisshown,byexample,thatupto1/3ofchannelcapacitycanbesavedbythenewsysteminsomespecialsituations.Inordertofindwhichblockcodeissuitabletouseinlength-varyingcodingsystem,theperioddistributionofthecodehastobecal-culated.Newrwsultsabouttheperioddistributionarepresentedwhilemanyopenproblemsremain.

简介：Consideringthejointchannelestimationanddatadetectionintime-varyingorthogonalfrequencydivisionmultiplexing(OFDM)andaddressingtransmissionperformancedegradationinducedbythesevereinter-carrierinterference(ICI)atveryhighspeed,anewprogressiveiterativechannelestimationschemeisproposed.ToalleviatetheerrorpropagationoftheinaccuratedataduetoICI,themeasurementsubcarriersintheKalmanfilterisdesignedtobeextendedfrompilotssubcarrierstoallthesubcarriersprogressivelythroughtheiterations.Furthermore,initerationprocess,theinterferenceofthenon-pilotdatatothemeasurementsubcarriersisconsideredtobepartofnoiseinthemodifiedKalmanfilter,whichimprovestheestimationaccuracy.Simulationindicatesthattheproposedschemeimprovestheperformanceinfasttime-varyingsituation.

简介：Inlongtermevolution(LTE)uplinksinglecarrierfrequencydivisionmultipleaccess(SC-FDMA)system,therestrictionthatmultipleresourceblocks(RBs)allocatedtoausershouldbeadjacent,makestheresourceallocationproblemhardtosolve.Moreover,withthepracticalconstraintthatperfectchannelstateinformation(CSI)cannotbeobtainedintime-varyingchannel,theresourceallocationproblemwillbecomemoredifficult.Inthispaper,anefficientresourceallocationalgorithmisproposedinLTEuplinkSC-FDMAsystemwithimperfectCSIassumption.Firstly,theresourceallocationproblemisformulatedasamixedintegerprogrammingproblem.Thenanefficientalgorithmbasedondiscretestochasticoptimizationisproposedtosolvetheproblem.Finally,simulationresultsshowthattheproposedalgorithmhasdesirablesystemperformance.