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2012 IEEE Radar Conference, May 7-11, Atlanta Plenary Talk Advances in Technologies and Architectures for Low-Power and Highly Integrated Ubiquitous Radars.

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Presentation on theme: "2012 IEEE Radar Conference, May 7-11, Atlanta Plenary Talk Advances in Technologies and Architectures for Low-Power and Highly Integrated Ubiquitous Radars."— Presentation transcript:

1 2012 IEEE Radar Conference, May 7-11, Atlanta Plenary Talk Advances in Technologies and Architectures for Low-Power and Highly Integrated Ubiquitous Radars Prof. Sergio Saponara, PhD sergio.saponara@iet.unipi.it Department of Information Engineering University of Pisa University of Pisa.

2 2012 IEEE Radar Conference, May 7-11, Atlanta Outline of the Talk Scenarios, applications and requirements for highly-integrated low-power RADAR RADAR architecture, integration levels, RF/mm- Wave transceivers and ADC Ubiquitous low-power RADAR case studies: E-health (UWB and Doppler) Automotive (FMCW) HW-SW implementing platforms for RADAR DSP Conclusions

3 2012 IEEE Radar Conference, May 7-11, Atlanta The electronic components market is growing, driven by digital-based highly integrated applications in Si- based tech. addressing societal needs: health, energy, security, safety, transport.. Not only nanoscale CMOS (more Moore) but also (more than Moore) System-in-Package integration of passives, RF & mm-Wave, high voltage, sensors/actuators (MEMS).. Source: World Semiconductor Trade Statistics

4 2012 IEEE Radar Conference, May 7-11, Atlanta Ubiquitous RADAR applications Pushed by military applications in II world war with high-power, large size and long-distance systems, today RADAR can be ubiquitous adopted for: Safer transport systems in automotive, railway, ships … Bio-signal detection for health care and elderly/infant monitoring Info-mobility in urban, airport or port scenarios Civil engineering, (structural health monitoring, landslide monitoring, ground penetration for detecting pipes, electric lines,….) Distributed surveillance systems (smart cities, airports, banks, schools) mm-wave body scanner for security Environmental monitoring and civil protection Contactless industrial measurements and in harsh environments Through-wall target detection

5 2012 IEEE Radar Conference, May 7-11, Atlanta Ubiquitous highly-integrated low-power RADAR RADAR sensing advantages w.r.t. other technologies: operations in all weather and bad light conditions contactless sensing and no line of sight sensing non ionizing radiations ground penetrating capabilities multi parameter sensing (target detection, distance, speed, angles) RADAR sensing suited to address societal needs (safety, security, health, transport )  ubiquitous adopted for large volume applications?

6 2012 IEEE Radar Conference, May 7-11, Atlanta W.r.t. conventional RADARs with large transmitted-power x antenna aperture product, the realization of highly-integrated RADARs with low power consumption, size, weight and cost (using standard technologies) is needed to enable its ubiquitous adoption in large–volume markets Transmitted Power < 10-15 dBm Short wavelength for miniaturization (3.9 mm@77 GHz) Range from < 1m to < 100-200 m Detection also with low SNR of 10-20 dB Cross section from tens of cm 2 to m 2 DSP techniques to improve performance and solve range-speed ambiguities Receiver sensitivity down to -100 dBm Multiple channels may be used for channel diversity gain Ubiquitous RADAR design needs

7 2012 IEEE Radar Conference, May 7-11, Atlanta At λ of few mm there is potential for high miniaturization, even the antenna integration 77-81 GHz suited for LRR and SRR, 60 GHz reserved for short range radio Today, good microwave and mm-Waves performance for Si-based technologies Highly integrated ubiquitous RADAR frequency

8 2012 IEEE Radar Conference, May 7-11, Atlanta Outline of the Talk Scenarios and applications for highly-integrated low-power RADAR RADAR architecture, integration levels, RF/mm- Wave transceivers and ADC Ubiquitous low-power RADAR case studies: E-health (UWB and Doppler) Automotive (FMCW) HW-SW implementing platforms for RADAR DSP Conclusions

9 2012 IEEE Radar Conference, May 7-11, Atlanta RADAR as mixed analog-digital system High peak power in integrated systems problematic  limit on range, performance gain from DSP rather than power Integrated high freq T/R (LNA, Mixer, switch, stable LO, ) and embedded I/F and BB DSP platforms (ADC/DAC + MCU + FPGA/DSP) Signal Processing TX: waveform gener (DDS), DUC RX: DDC, beam- forming, PC- match filter, FFT,.. ADC DAC ANALOG DOMAIN (PA, LNA, LO, MIXER, AGC, FILT, T/R Switch, Phase Shift) Data Processing (adaptive threshold, CFAR detection, tracking, classification..) Control & Interface (user or networking or mission processor) DIGITAL DOMAIN

10 2012 IEEE Radar Conference, May 7-11, Atlanta Low-power RADAR integration levels System-on-Chip (SoC), System-in-Package (SiP) or Single-board RADAR SiP is a more viable solution for RADAR than fully SoC (increased miniaturization entails also increased tech. complexity)

11 2012 IEEE Radar Conference, May 7-11, Atlanta Pro/Con of RADAR integration Pro of Highly Integrated RADAR Component assembly minimized reducing cost, increasing reliability & lifetime Small size, small weight, low power consumption Increased reproducibility and lower cost for large volume production Con of Highly Integrated RADAR IC design has high Non Recurring Costs (CAD tools, foundry cost, design time and team design cost)  cost is minimized only for large volume production A single technology can not offer optimal performance for all RADAR subsystems (CMOS optimal for BB DSP, not for antenna design or RF PA or mm-Wave analog design) Low transmit power limits possible applications to short range ones

12 2012 IEEE Radar Conference, May 7-11, Atlanta High transmit power and large aperture antenna RADAR realized assembling multiple electronic boards, optimized for each subsystem For low-power ubiquitous RADAR assembling all sub-systems on the same single printed circuit board (PCB) -single chip (few mm 2 ) TX and RX chains at micro or mm-Wave domain and solid-state power amplifier (CMOS, SiGe, MMIC III-V technologies) -ADC/DAC in CMOS tech. IC -single chip baseband signal processing (DSP, FPGA or ASIC) in CMOS -memory modules (RAM and NV) -Antenna printed on the PCB Pulsed RADARs can use a single time-division antenna for TX/RX FMCW RADARs use separate TX/RX antennas RADAR-System-on-a-Board

13 2012 IEEE Radar Conference, May 7-11, Atlanta Integrated antennas Antenna integration trend at board level (printed antenna on PCB), package level (with LTCC realizing multi-layer circuits with integrated passives including the antenna), at chip level using MMIC or SoI At mm-waves (77 GHz RADAR or 60 GHz radio λ is few mm) realizing an integrated antenna becomes feasible (limited to short-range) Lot of works still to do to meet RADAR antenna spec (high gain, array for beam-forming or DOA estimation)  RADAR antennas are off-chip Single-chip antennas on MMIC or SOI tech. proposed in literature for 60 and 77 GHz (few dB gain)  only for SRR or using special dielectric lens antenna or smart resonator to improve the characteristics

14 2012 IEEE Radar Conference, May 7-11, Atlanta mm-Wave on-chip integrated antenna C. Person, IEEE BCTM 2010 Antenna type F (GHz) TechGain BW (GHz) FeederImped. 4 array Dipole77SiGe22Differential45Ω Slot Dipole24GaAs21.4CPW50 Ω Zig zag24CMOS1.5N/A 30 Ω Ap. Coupled Patch60CMOS77.8Balanced100 Ω Dipole60SiGe2.357CPS30 Ω Slot Antenna60CMOS105N/A Cavity backed folded dipole 60SiGe718CPS50 Ω Folded Dipole60SiGe88CPW100 Ω Yagi60SiGe79.4N/A50 Ω Spiral60CMOS SOI4.215CPW50 Ω (J. Hasch et al., IEEE Tran. Micr Theory Tech, 2012)

15 2012 IEEE Radar Conference, May 7-11, Atlanta Competing semiconductor tech. for RADAR FTFT Gain/NF ratio Cost Power Consumption Suited for HBTHigh MediumHighAnalog, RF Si CMOSMedium Low Digital SiGe BiCMOS High Medium Analog, RF, mixed-signal III-V HEMT Very HighHigh Mediummm-wave

16 2012 IEEE Radar Conference, May 7-11, Atlanta CMOS technology dominates logic & memory M. Bhor, IEEE ISSCC0’9

17 2012 IEEE Radar Conference, May 7-11, Atlanta SiGe vs. CMOS vs. III-V technologies For future, for large volume applications (60 GHz radio, RADAR?) the trend will be using CMOS also for mm-wave circuits. As an effect of device scaling a Ft higher than 150 GHz can be obtained Realizing a mm-wave transceiver in scaled CMOS technology (65 nm or lower), as baseband DSP, entails a lower area, higher integration and lower cost for large volume markets but also lower performance vs. 130nm BiCMOS SiGe tech

18 2012 IEEE Radar Conference, May 7-11, Atlanta CMOS capability- LNA (Gain & NF) State-of-art designs up to 10-20 GHz in CMOS technology have good performances: gain higher than 20 dB, NF lower than 4 dB At higher frequencies the performances start decreasing. Around 77 GHz (W-band) acceptable but non optimal performance are achieved today (gain lower than 20 dB, NF higher than 4 dB) 10 15 20 25 110100 F (GHz) Gain, dB - CMOS LNA 0 2 4 6 8 10 1 100 F (GHz) NF, dB - CMOS LNA

19 2012 IEEE Radar Conference, May 7-11, Atlanta CMOS and SiGe capability- PA 0 5 10 15 20 25 30 35 1101001000 F (GHz) Pout TX, dBm - CMOS PA A. Scavennec et al., IEEE Microwave Mag. 2009

20 2012 IEEE Radar Conference, May 7-11, Atlanta Migration to SOI for better passive integration In SOI technology the high resistivity of the substrate on which n- and p- MOSFET are created allows dielectric isolation of circuit elements (bulk 20 Ω/cm, SOI > 1000 Ω/cm) Junction capacitances are reduced increasing maximum operating freq Reduced noise coupling between digital-analog parts in the same chip The performances of CPS, CPW or antennas in SOI CMOS are improved due to a reduced amount of energy loss in the supporting substrate

21 2012 IEEE Radar Conference, May 7-11, Atlanta Incidence of substrate resistivity on achievable radiation efficiency and gain Integrated antenna in CMOS SOI F. Gianesello, IEEE SOI 2010

22 2012 IEEE Radar Conference, May 7-11, Atlanta ADC – RADAR requirements ADC operating at IF: sampling rates up to tens, or even hundreds, of MS/s ADC sampling at several GS/s available but too power hungry and poor bit resolution  Mixer is needed, full-digital RADAR is not convenient Multi-channel ADC required (e.g. 4 in last LRR automotive Bosch RADAR) Bit resolution typically higher than 10 b, e.g. a nominal 14b-16 b required for 12 b-14 b ENOB (70 dB dynamic) Figure of Merit (FoM) in CMOS tech. from fJ to pJ per conversion-step M. Mishali et al. IEEE Signal Proc. Mag. 2011

23 2012 IEEE Radar Conference, May 7-11, Atlanta Outline of the Talk Scenarios and applications for highly-integrated low-power RADAR RADAR architecture, integration levels, RF/mm- Wave transceivers and ADC Ubiquitous low-power RADAR case studies: E-health (UWB and Doppler) Automotive (FMCW) HW-SW implementing platforms for RADAR DSP Conclusions

24 2012 IEEE Radar Conference, May 7-11, Atlanta Needs for health monitoring Due to aging population and needs of national health system cost reduction there is high interest in monitoring electronic health devices, specially for heart or respiratory pathologies (CHF, BPCO) A low-cost RADAR can be used as contactless sensor for monitoring heart rate or breath rate in patient with cardiopulmonary illness or to monitors babies while sleeping against sudden infant death syndrome Acquired RADAR data are then processed by an home gateway an send to Hospital Information Server

25 2012 IEEE Radar Conference, May 7-11, Atlanta Why RADAR for vital signs sensing A RADAR senses the mechanical activity of heart or chest instead of the electrical one; from that the heart/breath rate is detected and estimated The RADAR bio sensor can ensure continuous home monitoring avoiding wires, gels, LOS requirement, electrodes of conventional solutions based on SpO2 measures and multi-lead ECG acquisition (prone to electrode error positioning when done outside hospital ) Sensor RADAR requirements are low-power and high miniaturization for portability/wearability, short-range, low cost for large volume market  CMOS silicon integrated approach should be followed No ionizing effect

26 2012 IEEE Radar Conference, May 7-11, Atlanta Recent proposals based on Ultra Wide Band pulsed RADAR (within 3-10 GHz range) for very low power and low complex short-range (tens of cm) contactless vital sign detection Correlator-type receiver (Zito, De Rossi, Neri, architecture 2007- 2010, implementation in 90 nm CMOS 2011-2012), (Ta-Shun Chu et al., 130 nm CMOS implementation in 2011) Doppler RADAR based on transmission of un-modulated signal and the analysis of the received echo phase modulated by the chest/heart movement (Dracourt 2004, several works by J. Li, J. Lin et al.). Various designs at 450 MHz, 1.6 GHz, 2.4 GHz, 5.8 GHz in various technologies (250 nm CMOS and BiCMOS, 130 nm CMOS,..) Which RADAR architecture?

27 2012 IEEE Radar Conference, May 7-11, Atlanta UWB pulsed RADAR Very low power spectral density (-41.3 dBm/MHz from 3.1 to 10 GHz, 14 bands each of 500 MHz) – ETSI/FCC regulation Robust against interference, no ionization effect Transceiver activated when needed (low power) narrowband UWB noise Narrowband

28 2012 IEEE Radar Conference, May 7-11, Atlanta UWB pulsed RADAR Due to low power the RADAR is limited to detection of heart/breath rate of few Hz, at distances of tens of cm Single TX/RX antenna multiplexed in time Transmitter: pulse generator in the TX path transmits short pulses, typ 200-400 ps, towards the human body with fPR > 1 MHz so that the heart can be considered motion-less between consecutive pulses. The energy level of each pulse amounts to few pJ Low-complex cross correlation receiver architecture Zito et al., IEEE TBCS, 2011

29 2012 IEEE Radar Conference, May 7-11, Atlanta UWB pulsed RADAR Output signal modulated by the heart movement (RCS of tens of cm 2 ) After a TOF (e.g. few ns for 15-30 cm distance) the signals reflected by the target is captured by the RX antenna The signal amplified by the LNA is multiplied with a delayed replica of the transmitted pulses generated on-chip by a Shaper circuit The output signal amplitude is related to the heart position. Vital signs vary within a few Hertz A 3dB integrator band (Bint) of 100Hz allows an accurate detection Vo (t) at multiplier output Vout (t) at integrator output

30 2012 IEEE Radar Conference, May 7-11, Atlanta Correlation-type Receiver Averaging several pulses allows increasing SNR (40 dB, 10 4 pulses) At the low frequency (DC-100 Hz) of the baseband bio-signal the MOS transistors suffer 1/f flicker noise, higher than thermal noise (KTB term) To have NF tot ~NF LNA 20 dB gain required for the LNA if NF 2 <15 dB  LNA in 90 nm CMOS: 22.7dB gain, 6dB NF, -19dBm ICP1,<35 mW, <0.7 mm 2 (6) Fully differential Gilbert cell mul in 90 nm CMOS with NF 14.3 dB, 12 dB gain, 3.7 mW, 0.3 mm 2

31 2012 IEEE Radar Conference, May 7-11, Atlanta Pulse generator based on triangular pulse generation (TPG) and shaping network (SN): two triangular pulsed (delayed by a pulse period) generated and shaped by a CMOS differential pair Transmitter

32 2012 IEEE Radar Conference, May 7-11, Atlanta f PR in the range 1-10 MHz, pulses of 300-400 ps and 7-8 pJ energy BB digital processing can be realized with a simple MCU: low-speed ADC required (12b in ISSCC’11), low data rate serial connection, mainly control tasks to be implemented Whole chip by Zito et al. in 90 nm CMOS has <2 mm 2 area, < 80 mW power consumption, 40dB SNR integrator improvement, <1m range RADAR packaged in QFN32 and mounted on a test-board including antennas (TX and RX) with 2.3 dBi gain at 3.5 GHz, band 2.8 to 5.4 GHz covering the range of interest from 3 to 5 GHz. Performance of state of art UWB RADARs

33 2012 IEEE Radar Conference, May 7-11, Atlanta Doppler Bio RADAR Un-modulated signal transmitted towards the human body, where it is phase modulated by the physiological movement, then reflected and captured by the receiver (  h and  r are heart and respiratory rate) Using the same TX signal as RX LO signal, the receiver down-converts the echo signal into BB with no frequency offset. Here it is digitized and the physiological movement can be identified by DSP (FFT or wavelet) C. Li et al., IEEE TIM 2010

34 2012 IEEE Radar Conference, May 7-11, Atlanta Doppler Bio RADAR DR at 5.8 GHz (1 GHz bandwidth) realized in 130 nm CMOS technology powered by 1.5V batteries with direct conversion quadrature receiver The LNA has 2.56 dB NF and 24 dB gain; the whole RX chain has min 37 dB gain, -32 dBm P1dB, sensitivity of -101 dBm The system is sized to ensure 10-20 dB SNR, using a baseband sampling rate of 20 Hz (ADC is sized for 1 kHz) Off-chip 2x2 patch antennas (separate for TX and RX) were used With 7 dBm output power detection up to 3 m can be done C. Li et al., IEEE Tran. Micr. Theory Tech. 2010

35 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive RADAR – Why? Automotive RADARs as core sensor (range, speed) of driver assistance systems: long range (LRR) for Adaptive Cruise Control, medium range (MRR) for cross traffic alert and lane change assist, short-range (SRR) for parking aid, obstacle/pedestrian detection W.r.t. to other sensing technologies RADAR is robust in harsh environments (bad light or weather, extreme temperatures) Multiple RADAR channels required for additional angular information Data fusion in the digital domain with other on-board sensors

36 2012 IEEE Radar Conference, May 7-11, Atlanta First tentative for mm-wave automotive RADAR since 70’s but integrated-unfriendly technologies lead to large size, high cost Since 1998-1999 first generation of RADAR sensors (Daimler, Toyota) Since 2000 MMIC GaAs-based RADAR in premium cars Last generation based on 180/130 nm SiGe chipset and advanced packaging with integrated antenna commercially available (e.g. Bosch) Radar CMOS transceivers recent announced in 65 nm and 90 nm High RADAR frequency (small λ) allows small size and weight; highly integration with SiGe and future CMOS tech. will reduce assembly and testing costs and hence final user cost much below US$1000 Market expanding at 40%/year and is expected increasing with all premium/middle cars having a RADAR in next years (7% of all vehicles sold world-wide, mainly in Europe, Japan and US, will have RADARs) Automotive RADAR –a bit of Story

37 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive RADAR – Regulation 24 GHz and 77 GHz are the dominant bands for automotive 77-81 GHz is promising since offers 4 GHz bandwidth

38 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive RADAR – 24 vs. 77 GHz 77 GHz is more challenging for designers: given the same technology the node performances (gain, NF,..) at 24 GHz are better but 77 GHz RADARs reduce size, volume, weight and hence cost 77 GHz offers more opportunity for high performance RADAR design: λ is 3 times smaller (few mm)  smaller antenna size for a given beam- width spec and/or better angular separability for the same size Combination of high transmit power and high bandwidth available at 77 GHz for long range operation and fine distance separability Due to SiGe and CMOS technologies evolution 77 GHz is affordable 77-81 GHz (under regulation worldwide) offers 4 GHz Bandwidth with EIRP max PSD of - 3dBm/MHz (-9 dBm/MHz outside the vehicle)

39 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive RADAR – Technical spec (J. Hasch et al., IEEE Tran. Micr Theory Tech, 2012) RCS pedestrian: 0.3 -0.5 mm 2, RCS vehicle: 1-20 m 2

40 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive commercial RADARs Product size is in the order of 7 cm per side in LRR, 5 cm per side or lower in MRR and SRR Products exist with mechanical (slowly, increased size) or electronic beam forming (increased electronic complexity affordable in new tech nodes) Multi channel transceivers required All use FMCW RADAR technique (J. Hasch et al., IEEE Tran. Micr Theory Tech, 2012)

41 2012 IEEE Radar Conference, May 7-11, Atlanta FMCW automotive RADAR principle Received signal at the ADC (with up and down chirp, two targets are ambiguous; with four chirps two targets can be easily resolved )- LFMCW, FSKCW, MFSCW

42 2012 IEEE Radar Conference, May 7-11, Atlanta FMCW automotive RADAR equations Receiver power and SNR (min 10 dB required) Range and relative speed detection from batiment frequency analysis (with FFT in digital domain) The FMCW sweep frequency B and the time sweep determine the achievable range resolution and speed resolution

43 2012 IEEE Radar Conference, May 7-11, Atlanta Automotive RADAR with SiGe mm-Wave T/R Commercially available from Bosch based on SiGe Infineon Chipset 2 PCB boards FCMW modulation LRR 7dBm Pout, 4 channels (2 TX/RX, 2 RX only), dielectric lens antenna provides high gain for Rmax 250m Alternative versions with PCB or on- chip Integrated antennas Power consumption in the order of Watts B. Fleming, IEEE Vehicular Tech. Mag. 2012

44 2012 IEEE Radar Conference, May 7-11, Atlanta Block diagrams of automotive RADAR with SiGe mm-Wave T/R (J. Hasch et al., IEEE Tran. Micr Theory Tech, 2012)

45 2012 IEEE Radar Conference, May 7-11, Atlanta JSSC2011JSSC2010IEEEAESM 2012 Technology 65 nm CMOS 90nm CMOS guidelines for CMOS Power consumption 243 mW517 mwN/A Area1 mm 2 6.8 mm 2 N/A Carrier frequency77 GHz Resolution20 cmN/A< 1m Doppler resolution5 km/hN/A~5 km/h Range and antenna gain 106 m with off-chip 24 dB antenna 10 m with off-chip 20 dB antenna >100m with off-chip 24 dB antenna, <10 m with on-chip 4 dB antenna On-chip PA output5 dBm-2.8 dBm<10 dBm RX gain LNA+mixer+IF ~38.7 dB 23 dB LNA+mixer ~40 dB Sweep time Tm1.5 ms0.5 ms~1 ms Sweep freq. B700 MHz614 MHz150-750 MHz FFT points2048, 3 MS/s4096, 2 MS/sup to 8192, few MS/s Performance of CMOS transceivers Today SiGe-based RADAR T/R for commercial automotive RADAR Tomorrow CMOS-based expected (given technology evolution and trends towards more digital systems)

46 2012 IEEE Radar Conference, May 7-11, Atlanta Single and multi beam-forming To form a beam in a direction, each element of the array is followed by a time delay (phase shifters for narrow band) when all the outputs are summed they add up coherently to form a beam Analog beam-forming Digital beam-forming Figures from Skolnik book Analog/digital beam-forming

47 2012 IEEE Radar Conference, May 7-11, Atlanta DOA estimation - Monopulse It needs two beams for each angular coordinate Sum  and difference Δ patterns are used H. Rohling, Automotive Radar tutorial, 2008 Example, with Gaussian antenna pattern and -3dB beam-width=3 o

48 2012 IEEE Radar Conference, May 7-11, Atlanta Outline of the Talk Scenarios and applications for highly-integrated low-power RADAR RADAR architecture, integration levels, RF/mm- Wave transceivers and ADC Ubiquitous low-power RADAR case studies: E-health (UWB and Doppler) Automotive (FMCW) HW-SW implementing platforms for RADAR DSP Conclusions

49 2012 IEEE Radar Conference, May 7-11, Atlanta Implementing platforms for RADAR DSP Ubiquitous integrated RADAR applications (automotive, bio,..) needs low- power consumption (reduced power supply and thermal issues and increased portability) but can require high computational capabilities and large data transfer rate and memory storage size Energy-flexibility trade-off to be found between SW-oriented (GPP, DSP, GPU, Microcontroller) and HW-oriented (ASIC, FPGA) platforms R. Whil, IWPC 2011

50 2012 IEEE Radar Conference, May 7-11, Atlanta Custom SoC or MCU for RADAR Custom SoC design can provide the best in terms of performance (analog/RF/digital) for a given technology at minimum area and power occupation. Flexibility can be achieved adding in the ASIC also programmable cores ASIC development time and costs are high  rather than designing custom SoC for RADAR in next years an architecture based on MCU+ (DSP/FPGA) is more suited Thanks to the availability of IP cores such designs can be seen also a prototyping step towards a migration to SoC if and when RADAR becomes a commodity MCU has low-cost & low-power, on-chip ADC/DAC, but low-performance capabilities (MIPS rather than GOPS, integer operations, low data–rate digital I/O) For RADAR, MCU suitable for applications needing control of data/operation flow but a co-coprocessor is needed for DSP RADAR is not yet a commodity with accepted/frozen standards

51 2012 IEEE Radar Conference, May 7-11, Atlanta Why not General Purpose Processors (GPP)? GPP are evolving as SW-programmable computing architecture with many cores, large operand size (64b or higher), tens of GOPS, multiple cache levels (several Mbytes on chip) and fast connections to off-chip DDR memories or networks However the energy efficiency (<<1GFLOPS/Watt) and absolute power (tens of Watts) are far from specs of highly-integrated low-power RADAR applications Intel I5 multicore example

52 2012 IEEE Radar Conference, May 7-11, Atlanta Digital Signal Processors SW-programmable with instruction set optimized for DSP (e.g. ALU with HW resources for fast MAC, fixed or floating point versions available) Different architectural approaches: SIMD, VLIW up to GPU (TFLOPS performance higher than multi-core GPP and with better energy efficiency for DSP tasks) DSP for consumer, automotive and biomedical markets already available DSP available also as IP cores (soft or hard macro) to be integrated in custom IC

53 2012 IEEE Radar Conference, May 7-11, Atlanta GPU vs GPP Comparison of computational and bandwidth capabilities and power cost of some GPP and GPUs

54 2012 IEEE Radar Conference, May 7-11, Atlanta GPU vs GPP NVIDIA GTX260 GPU tested against Core2Duo GPP E8x series for several RADAR DSP classic algorithms GPU has a speed-up from 10% up to two orders of magnitude vs. GPP depending: the algorithms, the size of the input array data, the regularity and parallelization degree of the data flow, the bottleneck caused by memory transfers Large speed-up for filters Smaller speed-up for CFAR The GPU kernel is faster than the GPU computing platform considering also memory system Patterson et al, SAAB 2010

55 2012 IEEE Radar Conference, May 7-11, Atlanta FPGA (Field Programmable Gate array) FPGAs are evolving from reconfigurable HW devices to complex Systems on Programmable Chip (SoPC) with: integrated reconfigurable logic blocks (FF, LUT) and I/O blocks, memory blocks, DSP-units (Mult Add,) soft/hard SW cores (Microblaze, Nios, ARM Cortex,..) Different FPGA technologies exist: Flash (ProAsic), Anti-fuse (AX, RTAX), SRAM (Virtex, Spartan, Cyclone, Stratix) some already qualified for automotive or even space/military applications For DSP intensive applications SRAM-based are typically preferred Mixed-signal FPGAs also exist(Fusion) FPGA designs for DSP require algorithmic and HW know-how: HDL and synthesis tools

56 2012 IEEE Radar Conference, May 7-11, Atlanta High-end FPGA for RADAR DSP High-end FPGAs for intensive RADAR DSP are available but cost (>1000 USD) and power consumption are too high for ubiquitous low-power apps Virtex6 LX760 FPGA in 40 nm for FFT processing has 380 GFLOPS at 50 W Stratix Altera FPGA in 28 nm with variable precision DSP blocks, 2 TMACs Efficiency (GFLOPS/W, GFLOPS/mm 2 ): - FPGA worse vs. Custom IC (1 order of magnitude) - better performance by 1 order of magnitude vs. GPP - slightly better than GPU (GTX480) E. Chung, IEEE Micro 2010

57 2012 IEEE Radar Conference, May 7-11, Atlanta Cost-effective FPGA for RADAR DSP To fit the DSP RADAR requirements of low-cost low-power applications the challenge is an optimized algorithmic-architecture co-design on less complex FPGA families with HW-SW capabilities MCU+DSP functionalities of a FMCW automotive RADAR realized in Xilinx Virtex2Pro (Microblaze + radix-2 FFT processor 2048-point, 14 b) Control and DSP tasks of a 77 GHz FMCW RADAR with GaAs MMIC front- end and MEMS switch realized in Spartan-3A and Virtex-5 SX50T (switch control, TX sweep gen, Hamming filtering, FFT, CFAR, peak pairing) 11b ADC, 10b DAC, 12b/16b DSP data/coefficient resolution S. Lal, IEEE RSP 2011

58 2012 IEEE Radar Conference, May 7-11, Atlanta Cost-effective FPGA for RADAR DSP Virtex5 SX50T: 8160 slices (4 LUT+4FF), 5000 kb RAM; 288 DSP48 unit (25x18 mul+acc +adder), 12 DCM 6 PLL, fast I/O Spartan3 A-DSP (XA3SD1800A): 16640 slices (2LUT+2FF), 1500 kb RAM, 84 18x18 mul, 8 DCM, automotive grade device exist S. Lal, IEEE RSP 2011

59 2012 IEEE Radar Conference, May 7-11, Atlanta Conclusions RADAR sensing suited to address societal needs of safety, security, health- care, intelligent transport with big advantages vs. other technologies Differently from high power and large antenna RADARs, highly-integrated systems with low power consumption, size, and cost are needed for the ubiquitous adoption of RADARs in large–volume markets Opportunities for miniaturization at mm-waves (λ of few mm) Key enabling factor is the realization, in Si-based CMOS or BiCMOS tech., of integrated transceivers for the RADAR front-end with enough NF, gain and power to meet automotive or bio RADAR requirements The path to full CMOS/CMOS SOI to be completed as well as advanced concepts for System-in-Package integration to be further explored

60 2012 IEEE Radar Conference, May 7-11, Atlanta Conclusions ADC at IF and increasing RADAR signal processing in the digital domain (FFT, filtering, pulse comp., beam-forming, CFAR, tracking), with cost-effective embedded platforms (MCU+FPGA), allows for high performance RADAR in standard tech. at low power and low size Proof-of-concept demonstrators of ubiquitous low-power RADAR and first commercial solutions recently available for UWB pulsed RADAR for bio and FMCW automotive RADAR (LRR, MRR and SRR) RADAR advances also at system and algorithmic level: - Sensor fusion of RADAR systems with other sensor technologies - Networks of small RADARs used to improve the performance in terms of angular, speed, range accuracy and number of tracked targets - In networked RADAR scenario new DSP functions to be adopted (e.g. code division multiple access to avoid crowding, MIMO techniques)

61 2012 IEEE Radar Conference, May 7-11, Atlanta Acknowledgment Discussions with Bruno Neri, Full Professor of RF electronics and Maria S. Greco, Associate Professor of Telecommunications at University of Pisa are gratefully acknowledged Thanks for your attention


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