Ultra wideband communication system

wideband communication for implantable and wearable systems and wideband model in wireless communication
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Dr.ShivJindal,India,Teacher
Published Date:19-07-2017
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Overview: Trends and Implementation Challenges for Multi-Band/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 mm-wave 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, signal-to-noise, bandwidth, data rate, and/or Source: International roadmap for semiconductors ITRS 2005 inverse power. Application-specific 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 Radio-2  Basic Non-Cognitive 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 analog-to-digital 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 Front-end Digital Baseband MAC Layer Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007RF Front-End 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 Front-End: Analog/RF Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007RF Front-End 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 up-converter 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 spectrum-agile MIMO-based wireless node will require application-specific 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 front-end: - - -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: 2400-2483.5 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: Near-Far Problem  High power consumption due to simultaneous requirement of high linearity in RF front-end and low noise operation  The conflicting requirements occur since the linearity of the RF front-end 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 front-end for optimal performance Rensselaer Radio Frequency Integrated Circuits Lab. April 20th, 2007