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1、 2002Wireless Solution UpdateAsif Batada Marketing Manager, Wireless Business Unit天马行空官方博客：http:/ ；QQ:1318241189；QQ群：175569632 2002 AgendanMobile Base-station ArchitecturenBasics of Digital IF and Digital Predistortion LinearizernRF Card ArchitecturenPredistortion Linearizer ImplementationnConclusio
2、n天马行空官方博客：http:/ ；QQ:1318241189；QQ群：175569632 2002 AntennaRNC I/FIP InterfaceSwitch ControllerA/D D/ABase Band Signal ProcessingSwitch I/FHost Processor (CPU)Clock GeneratorPLD ApplicationControl BoardChannel CardRNCDigital IFDigital Predistortion LinearizerMux/ De-MuxHost uP RF CardBase-Station Arc
3、hitectureLVDS w/CDRATM procPALNA 2002 AgendanMobile Base-station ArchitecturenBasics of Digital IF and Digital Predistortion LinearizernRF Card ArchitecturenPredistortion Linearizer ImplementationnConclusion 2002 Digital IF OpportunitynDigital IF is a high volume application for FPGA: - Macro BTS ca
4、n be configured into two different ways:l2 carriers for 3 sectorsl1 carrier for 6 sectors- Each BTS has Digital IF Implementation: 6 x EP1S20 Predistortion Implementation: 6 x EP1S106 x EP1S20 + 6 x EP1S10 per BTS1 carrier (5Mhz for UMTS)6 Sector Cell603 Sector Cell120 2002 Traditional IF-Based Tran
5、smitternIssues with traditional transmitter - Not flexible to support multiple standards - Non-ideal local frequencies are source of noise - RF and analog components of radio are more difficult to manufacture and have higher reliability issues - Higher costBB filterBB filter+90f1IF filterRF filterf2
6、AmpPAIQDACDAC 2002 Digital IF Sym. MapperFIR filterNCOFIR filterf2AmpPAIF filterRF filterDigital Up-ConverternWith the advancement of data converter technology (100Msps +), it is possible to sample at IF (intermediate frequency) and do Channelization in Digital domainnAdvantages of Digital IF - Chan
7、nel selection can be done in digital domain - Higher precision in frequency selection and shorter settling time of DDS - Good amplitude and phase balance - Extremely linear phase and very low shape factor of base-band filterDAC 2002 Predistortion LinearizernRF stage (transmitter) uses a linear Power
8、 Amplifier (PA) to boost the signalsnLinear PAs are very expensive - Some cases it makes up half the cost of BTSnNon-Linear PAs are cheaper - LDMOS based technology - LDMOS introduces distortion of its ownnPredistortion in digital domain - Pre-distort the signal so that when it goes thru PA, the ove
9、rall response is linear - Common technique Look-up Table based approachlStore the points on the transfer function in a look-up tablelOne of our customers evaluating 20K400E for this applicationlNios is well suitedInput PowerOutput PowerAdd Predistortion 2002 AgendanMobile Base-station ArchitecturenB
10、asics of Digital IF and Digital Predistortion LinearizernRF Card ArchitecturenPredistortion Linearizer ImplementationnConclusion 2002 RF Card 1st Generation DesignnCustomers have either designed their own Digital IF chip (w/o DPD) or are using ASSP (mostly GrayChip)nLimitations with current implemen
11、tation: - Custom Filter Specs Adj Channel Power Ratio (ACPR) Requirement Driven by Architecture - Decimation and Interpolation Ratios Driven by Standards and Internal implementationnNeed to add more carriers - Availability of Multi-Carrier Power Amplifier - Higher capacity channel cardsnHigher Data
12、rates over the back plane 2002 InterpolationInterpolationRRC FilterRRC FilterRRC FilterResamplerDecimationRRC FilterResamplerDecimationNCOQADCDACToAntFromAntTo Channel Card (LVDS w/CDR)Input FmtSub-$20 in HardCopynSpeed and size improvements in FPGA can be easily leveraged to support more channels 2002 ConclusionnRF portion of base-station going through revisionnDigital Predistortion Linearizer is a key functionality being addednFPGA implementation offer significant advantage over ASSP implementationnAltera Offers comprehensive solution including devices, tools and IP
