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Overview: Trends and Implementation Challenges for Multi-Band/Wideband Communication

Overview: Trends and Implementation Challenges for Multi-Band/Wideband Communication 38
Overview: Trends and Implementation Challenges for MultiBand/Wideband Communication Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007What is RFIC •Any integrated circuit used in the frequency range: 100 MHz to 3 GHz (till 6GHz can sometimes be considered RF). Currently we are having mmwave circuits in Silicon (17GHz, 24GHz, 60GHZ, and 77GHz) •Generally RFIC’s contain the analog front end of a radio transceiver, or some part of it. •RFIC’s can be the simplest switch, up to the whole front end of a radio transceiver. •RFIC’s are fabricated in a number of technologies: Si Bipolar, Si CMOS, GaAs HBT, GaAs MESFET/HEMT, and SiGe HBT are today’s leading technologies. We are going to design in either CMOS, or SiGe. Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Basic Wireless Transceivers RF Receiver RF Transmitter Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007The last 10 years in wireless systems Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Where we are in terms of technology The metric for performance depends on the class of circuit. It can include dynamic range, signaltonoise, bandwidth, data rate, and/or Source: International roadmap for semiconductors ITRS 2005 inverse power. Applicationspecific wireless node implemented in a low cost technology (CMOS) can provide programmability, low cost and low power solution Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007The next 10 years Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Spectrum Utilization Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Introduction to Cognitive Radio  A Cognitive Radio (CR) can be defined as “a radio that senses and is aware of its operational environment and can dynamically adapt to utilize radio resources in time, frequency and space domains on a real time basis, accordingly to maintain connectivity with its peers while not interfering with licensed and other CRs”.  Cognitive radio can be designed as an enhancement layer on top of the Software Defined Radio (SDR) concept. Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Introduction to Cognitive Radio2  Basic NonCognitive Radio Architecture: Transmitter Data Antenna Processor and Modem Coupling Receiver Networked Device  Cognitive Radio architecture: Spectrum Scanning and Interference Avoidance Module Channel Spectrum Scanning Pooling Analysis Engine Engine Server Antenna Sharing Module TT ra ran ns sm miitt te te r r Processor Data Modem Processor Data Modem and Receiver and Receiver Networked Device Wireless Data Transceiver Subsystem Module Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Window of Opportunity  Existing spectrum policy forces  Recent measurements by the spectrum to behave like a fragmented FCC in the US show 70 of the disk allocated spectrum is not utilized  Time scale of the spectrum  Bandwidth is expensive and good occupancy varies from msecs to frequencies are taken hours  Unlicensed bands – biggest innovations in spectrum efficiency Time (min) Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007 Frequency (Hz)CR Definitions Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007 Today “spectrum“ is regulated by governmental agencies, e.g. FCC)  “Spectrum“ is assigned to users or licensed to them on a long term basis normally for huge regions like whole countries  Doing so, resources are wasted  Vision: Resources are assigned where and as long as they are needed, spectrum access is organized by the network (i.e. by the end users)  A CR is an autonomous unit in a communications environment. In order to use the spectral resource most efficiently, it has to be aware of its location be interference sensitive comply with some communications etiquette be fair against other users keep its owner informed  CR should  Sense the spectral environment over a wide bandwidth  detect presence/absence of primary users  Transmit in a primary user band only if detected as unused  Adapt power levels and transmission bandwidths to avoid interference to any primary user Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007CR Definitions Digital Radio (DR): The baseband signal processing is invariably implemented on a DSP. Software Radio (SR): An ideal SR directly samples the antenna output. Software Defined Radio (SDR): An SDR is a presently realizable version of an SR: Signals are sampled after a suitable band selection filter. Cognitive Radio (CR): A CR combines an SR with a PDA radio frontend analogtodigital baseband data radio conversion frequency processing processing A/D RF 1) According to control J. Mitola, 2000 (parametrization) Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007 transmit receive from us er t u er o sCognitive radio Functions  Physical Layer  Sensing Radio MAC Layer • OFDM transmission • Wideband Antenna, PA • Optimize transmission and LNA parameters • Spectrum monitoring • High speed A/D D/A, • Adapt rates through • Dynamic frequency moderate resolution feedback selection, modulation, • Simultaneous Tx Rx power control• Negotiate or opportunistically use • Analog impairments • Scalable for MIMO resources compensation A A AD D DA A AP P PT T TIIIV V VE E E T T TIIIME ME ME,,, FR FR FRE E EQ, Q, Q, QoS QoS QoS vs. vs. vs. M MA AE E// PA PA PA D/ D/A A IFFT IFFT IFFT S S SP P PA A AC C CE E E S S SE E EL L L LO LO LOA A AD D DIIIN N NG G G R R RA A AT T TE E E P PO OW WE ER R C CT TR RL L IIIN N NT T TE E ER R RFE FE FER R RE E EN N NC C CE E E C CH HA AN NN NE EL L LE LE LEA A AR R RN N N FE FE FEE E ED D DB B BA A AC C CK K K LNA FFT FFT FFT A/D ME ME MEA A AS S S///C C CA A AN N NC C CE E EL L L S SE EL/ L/E ES ST T T T TO O O CRs CRs CRs E E EN N NV V VIIIR R RON ON ONME ME MEN N NT T T RF/Analog Frontend Digital Baseband MAC Layer Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007RF FrontEnd Schematic Analog Digital L Low ow n noise oise Converters am amp pli lif fie ier r LO LO A/D Baseband Up down RF Waveguide Digital amplifiers frequency filters filters Processor and filters converters D/A P Pow owe er r LO LO am amp pli lif fie ier r Digital L Loc ocal al oscill oscillat ato or rs s Mixed FrontEnd: Analog/RF Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007RF FrontEnd Challenges Wideband Wideband down Wideband or converter amplifier LNA multiband Program antenna filter mable Filter s w Agile A/D End User i Digital LO t Wideband Equipment Processor amplifier c upconverter D/A Program h filter mable •Baseband switch Filter Wideband •Crypto power Agile •Modem amplifier LO Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Motivation  Intelligence and military application require an application specific low cost, secure wireless systems.  An adaptive spectrumagile MIMObased wireless node will require applicationspecific wireless system:  Reconfigurable Radio (operating frequency band, bit rate, transmission power level, etc)  Wide frequency coverage and agility  Work independent of commercial infrastructure  Large instantaneous bandwidth Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007System Challenges  A/D converter: – High resolution – Speed depends on the application 40 40 40 – Low power 100mWs C C Cell ell ell 45 45 45  RF frontend: 50 50 50 PC PC PCS S S – Wideband antenna and filters T T TV V V b b band and ands s s 55 55 55 – Linear in large dynamic range 60 60 60 – Good sensitivity 65 65 65  Interference temperature: 70 70 70 75 75 75 – Protection threshold for licensees 80 80 80 – FCC: 24002483.5 MHz band is empty if: 85 85 85 90 90 90 0 0 0 0.5 0.5 0.5 1 1 1 1.5 1.5 1.5 2 2 2 2.5 2.5 2.5 9 9 9 Fre Fre Frequenc quenc quency y y (Hz) (Hz) (Hz) x x x 10 10 10  Need to determine length of measurements Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007 S S Signa igna ignal l l S S Strengt trengt trength ( h ( h (dB) dB) dB)System Challenges Receiver • Wideband sensing • Different primary user signal powers and types • Channel uncertainty between CR and primary user Transmitter • Wideband transmission • Adaptation • Interference with primary user Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Dynamic Operation: NearFar Problem  High power consumption due to simultaneous requirement of high linearity in RF frontend and low noise operation  The conflicting requirements occur since the linearity of the RF frontend is exercised by a strong interferer while trying to detect a weak signal  The worst case scenario is a rare event.  A dynamic transceiver can schedule gain/power of the frontend for optimal performance Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Advantages of CR  Cognitive radios are expected to be powerful tools for mitigating and solving general and selective spectrum access issues (e.g. finding an open frequency band and effectively utilizing it).  Improves current spectrum utilization (Fill in unused spectrum and move away from occupied spectrum ).  Improves wireless data network performance through increased user throughput and system reliability.  More adaptability and less coordination required between wireless networks. Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Systems Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Basics of UWB Signaling Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Definition of UWB Systems Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Why UWB Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Applications Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Sensors Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Sensor Architectures Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB receiver Architecture Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB receiver Architecture Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Multiband OFDM UWB Architecture Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Multiband OFDM UWB Radio Architecture Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Comparison of MBOFDM radios Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Components/Subsystems Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Levels of Integration Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007UWB Basic Building Blocks (Pulse Generator) Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Challenges in UWB IC Design Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Challenges in UWB IC Design Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Future Trends Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Future Trends; UWB Beam forming Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Multiband VCO 5.47.0GHz 1.722.25GHz 5.47.0GHz 2.73.5 GHz 1.722.25GHz 0.861.12GHz M 1/2 U X 1/4 1.351.7GHz 0.430.56GHz  Existing Multiband VCOs/Frequency References are based on:  Switched inductor and/or capacitor LC tanks (Extra parasitics and resistive loss  degrade both tuning range and phase noise)  Frequency dividers (higher phase noise and power consumption)  MEMS resonators (nonstandard process, extra processing steps, higher fabrication cost) Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007MultiBand VCOSchematic  LowBand and High Band Switching between bands: Enable/Disable a buffer InBand Tuning: “Primary” and “secondary” varactors Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007Future Trends • Wireless Control of machines and devices in the process and automation industry • Logistic Radio Frequency B Biio os se en ns so or r DC DC G Ge en ne er r Identification (RFID), includes a at tiio on n R RF F C Communicat ommunication ion C Cir ircuit cuit transportation, terminals, and warehouses. RF RF Powered Powered Wireless Wireless Communication Communication RF RF Powered Powered Wireless Wireless Communication Communication Circuits Circuits for for Bio Bio Implantable Implantable Circuits Circuits for for Bio Bio Implantable Implantable • Smart home appliance, remote Microsystems Microsystems Mic Micro rosy syste stems ms controls • Medical monitoring health conditions (wireless body area network WBAN) • Environmental monitoring, such as smart dust or other ambient intelligence Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 20073D RF System Integration LNA input matching Antenna One Possible Antenna Implementation PA output matching Sisubstrate SiGe/CMOS Chip Al IF LPF ADC BCB Glass Substrate LNA OSC. PA Integrated Antenna IF LPF DAC High Q inductors (top glass layer or interwafer inductors Digitally assisted RF/Analog Design (All blocks can be optimized through vertical control signals) DSP Baseband Power Amplifier linearization Digital pre DCDC distortion or dynamic bias through bottom layer Converter monolithic DCDC Converter Added functionality/versatility Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 20073D MicroPower Portable/Implantable RF Wireless Systems for Biomedical Applications. Wireless Body Area Network Antenna (WBAN) EEG Communications Passive HEARING VISION layer POSITIONING GLUCOSE UWB IF LNA BLOOD LPF ADC PRESSURE RF OSC. Transceiver CELLULAR LPF PA IF DAC TOXINS WLAN DNA PROTEIN Sensing IMPLANTS Processor/ Digital processing power Control distribution DCDC Converter and layer power distribution (a) (b) Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007 NETWORK
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