AFFILIATION LOGO Non Linear Distortion and Dynamic Range Issues Non Linear Distortion and Dynamic Range Issues in the Design Of Microwave Electronics for in the Design Of Microwave Electronics for Communication and Remote Sensing Systems Communication and Remote Sensing Systems Alberto Santarelli Santarelli Alberto Short course on: RF electronics for wireless communication and remote sensing systems Scuola di Dottorato in Scienze ed Ingegneria dell'Informazione Dottorato di Ricerca in Ingegneria Elettronica Informatica e delle Telecomunicazioni 13th, 14th and 20th July 2010, Facoltà di Ingegneria, Viale Risorgimento 2, Bologna
Summary Summary AFFILIATION LOGO • Brief Overview of Wireless Systems • Wireless T/R Front End Design Issues • Non linear distortion, noise and dynamic-range issues in building blocks of wireless communication and remote sensing systems. • Trade-off issues between nonlinear distortion, output power and power added efficiency in the design/optimization of microwave power amplifiers • Basics of new generation electron devices for low-distortion, high- dynamic-range microwave circuit design. A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 2
Wireless Systems Overview (I) Wireless Systems Overview (I) AFFILIATION LOGO Wireless Cellular Telephone Network (Typ. Freq. : 950, 1800, 2100 MHz) • (2G) GSM (mod. GMSK) - EDGE (mod. GMSK/8-PSK) • (3G) UMTS (mod. QPSK) – e.g. W-CDMA provides HSPA up to 7Mbs – Freq. Band 5MHz • (3GPP) LTE (mod. QPSK, 16-QAM, 64-QAM) – expected cell data rates of over 300 Mbps – Freq. Band up to 20 MHz • (4G) IP-based, Software Defined Radio (SDR), Cognitive Radio (CR) A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 3
Wireless Cellular Telephone Network Wireless Cellular Telephone Network AFFILIATION LOGO Base Terminal Station (BTS) • Downlink (from BTS to Handset) • Uplink (from Handset to BTS) e.g. QPSK - S/N req = 5dB Pout = 23 dBm UL DL e.g. 16-QAM - S/N req =11dB Pout = 43 dBm Different specs and technologies used for uplink and downlink… Fig. from Ref.[1] A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 4
Wireless Systems Overview (II) Wireless Systems Overview (II) AFFILIATION LOGO Wireless Local/Personal Area Network (WLAN/WPAN) WiFi • OFDM with subcarriers mod. PSK or QAM) • based on the IEEE 802.11 standards • Data rate up to 54 Mbit/s • Freq.: 2.4 GHz, 5 GHz, Bandwidth up to 22 MHz WiMax • based on the IEEE 802.16 standard • Multi-user channel access techniques such as OFDMA • Peak data rates of 144 Mbit/s in downlink and 35 Mbit/s in uplink (802.16e) • Freq. 2.3–2.5 GHz and the 3.4–3.5 GHz, Bandwidths up to 20 MHz MIMO channels available (multiple TX/RX antennas, spatial diversity) A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 5
Wireless Systems Overview (III) Wireless Systems Overview (III) AFFILIATION LOGO Mote Analog I/O Ports Analog I/O Ports Wireless Sensor Networks Sensor Sensor Radio Transceiver Radio Transceiver D/A D/A D/A A/D A/D A/D Microcontroller Microcontroller Microcontroller • Spatially distributed autonomous sensors Digital I/O ports Digital I/O ports Sensor Sensor External Memory External Memory • Equipped with a radio transceiver Power Supply or other wireless communications devices • Small dimensions, low-power consumption, Links to Other networks or Similar Super Nodes low data rate, secure networking • Typically based on the IEEE 802.15.4 standard (WPAN) Super Node Motes e.g. ZigBee in ISM radio bands and 2.4GHz A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 6
Wireless Systems Overview (IV) Wireless Systems Overview (IV) AFFILIATION LOGO Back-Haul – Terrestrial and Satellite Communications • Point-to-Point Terrestrial or via-Satellite Microwave Radio Links (e.g. connecting Base Stations) – dedicated high-capacitive terrestrial radio links at 38 GHz (mod. PSK/QAM) • Point-to-Multipoint Microwave Access Technologies (broadband, fixed wireless, point-to-multipoint technology) – WiMax – Local Multipoint Distribution Service (LMDS) at 28-29 GHz (PSK/QAM) A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 7
Wireless Systems Overview (V) Wireless Systems Overview (V) AFFILIATION LOGO Not only networks… Satellite Remote Sensing and Communication • Synthetic Aperture Radars • Altimeters and radiometer applications • Radioastronomy • Satellite Radio Links for video, audio and data broadcasting (DVB- S/S2) and Internet Access at 12GHz (downlink) and 18 GHz (uplink) (mod. BPSK, 16APSK and 32APSK) Frequency Bands: C – X – Ku and beyond… Reliability issues… A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 8
Basic Building Blocks of RF Front- -Ends Ends Basic Building Blocks of RF Front AFFILIATION LOGO • Power Amplifier (PA) – provides signal power amplification just before the transmitting antenna • Low Noise Amplifier (LNA) – provides amplification just after the receiving antenna by introducing minimal S/N degradation • Mixer – provides up and down frequency conversion of signals • Local Oscillator – provides sinusoidal waveform for carrier generation • Frequency Synthesizer – Provides stable and programmable carrier generation and recovery • Linear Filters and Phase Shifters– for band and channel selection, image rejection, IQ modulation, etc. • Duplexer - allows using a single antenna for TX/RX A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 9
Duplexing Duplexing AFFILIATION LOGO • Single antenna for RX and TX Half- • Time Division Duplexing (TDD) vs. duplex Frequency Division Duplexing (FDD) • RX has to be isolated from high power generated by HPA (otherwise: LNA desensitisation) FDD Full- duplex Figs. from Ref. 2 A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 10
Mixer Mixer AFFILIATION LOGO The mixer ideally executes a perfect ( ) ( ) v t v t multiplication of two input signals v A , v B S out = ⋅ ⋅ v ( ) t A v ( ) t v ( ) t out LO S v ( ) t The Mixer provides Frequency Conversion LO = ω = ω v ( ) t V cos t v ( ) t V cos t LO LO LO S S S A A ( ) ( ) = ω + ω + ω − ω v ( ) t V V cos t V V cos t out LO S LO S LO S LO S 2 2 Up-conversion Down-conversion • Actual Mixers suffer from noise and distortion A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 11
Example of a Microwave T/R Front- -End End Example of a Microwave T/R Front AFFILIATION LOGO Fig. from Ref. 2 Lucent Tech. GSM Transceiver A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 12
Typical Trends in T/R Front- -End Architectures End Architectures Typical Trends in T/R Front AFFILIATION LOGO • ADC and DAC progressively shift towards the antenna (Software Defined Radio) • Reconfigurable building blocks (“frequency-agile” RF components and systems) � Digital RF circuits � Analog RF circuits with digital control (e.g. with use of RF-MEMS) • High-efficiency PA schemes (Doherty Amplifiers, Class-S Amplifiers, Envelope Tracking,…) Fig. from Ref. 1 Linearity ??? PA Linearization techniques A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 13
Limiting Factors of Nonlinear RF Building Blocks Limiting Factors of Nonlinear RF Building Blocks AFFILIATION LOGO Nonlinear RF building blocks of T/R Front Ends (PA, LNA, Mixer, Oscillator and Frequency Syntethasizer) are basically limited in performance by • Broad-band and Parametric Noise DYNAMIC RANGE • Nonlinear Distortion Component Dynamics cannot be neglected at microwaves • • Power consumption (energetic efficiency, self-heating, reliability) • Transmission of Wide-Band signals leads to critical requirements for the Receivers in terms of robustness against strong Interfering Signals Flexibility and Reconfigurability • A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14 th July, 2010 14
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