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Low Power RF RF Basics and Getting Started Wirelessly connecting everywhere. May 2012 everything.

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Presentation on theme: "Low Power RF RF Basics and Getting Started Wirelessly connecting everywhere. May 2012 everything."— Presentation transcript:

1 Low Power RF RF Basics and Getting Started Wirelessly connecting everywhere. May 2012 everything

2 Abstract This presentation serves as an overview of the parameters and considerations a designer would use to select a low- power wireless solution. It also highlights the devices and tools from TI and how they fit in a typical design.

3 3 Broad range of applications Consumer / personal networking Industrial remote monitoring Shipment monitoring  Watch/shoe combination for monitoring of miles and calories  Enough processing for wireless networking and batteries that 10+ years  Low power sensor networks for innovative applications like remote monitoring for stress cracks  Harvest energy from motion, vibration and heat  Information transmitted wirelessly is protected via encryption for more secure systems  Location, tamper detection and temperature monitoring

4 Product line up Sub 1GHz2.4GHz to 5GHzSatellite13.4KHz /13.56MHz SimpliciTI PurePath™ Wireless Bluetooth® technology Bluetooth® low energy ANT™ GPSRFID NFC ISO14443A/B ISO15693 SimpliciTI 6LoWPAN W-MBus ZigBee® 6LoWPAN RF4CE Wi-Fi a/b/g/n Wi-Fi + Bluetooth® technology TMS37157 TRF796x TRF7970 CC2500 CC2510 CC2590 /91 CC8520 /21 CC8530 /31 CC2560/7 CC2540 CC2570/1 CC2520 CC2530 CC2530ZNP CC2531 CC2533 WL1271/3 WL1281/3 NL5500 CC1101 CC1110 CC430 CC1190 CC11xL CC112x Example applications TI’s portfolio: The industry’s broadest

5 Definitions RF Systems Introduction to digital communication Radio Frequency: Spectrum Tools Agenda

6 Basic system parameter definitions RF power RF power is typically measured in dBm (dB relative to 1mW) Link budget Difference between input sensitivity and output power in (dB) PER Packet Error Rate, % of packets not successfully received Sensitivity Lowest input power with acceptable link quality, typically 1% PER Blocking/selectivity How well a chip works in an environment with interference Deviation/separation Frequency offset between a logic ‘0’ and ‘1’ using FSK modulation

7 dBm – power referred to 1 mW, P dBm =10log(P/1mW) 6dB increase in link budget => twice the range Typical power levels

8 Receiver Sensitivity The minimum signal power required by receiver to demodulate the received information with less than 1% bit error rate (BER) Saturation Highest input power level the receiver can demodulate correctly Dynamic Range = Saturation - Sensitivity Data rate -103 kbps -123 kbps -114 kbps -110 kbps SensitivityCC1120 (868/915 MHz) Minimum useable sensitivity (ETSI EN 300 V2.3.1 limit) 10log[RX BW kHz /16] – 107 dBm Sensitivity and Saturation

9 Selectivity / Blocking Describes how well interfering signals are rejected For a receiver with very poor selectivity, frequency hopping will not help much, as even off-frequency interference is not attenuated sufficiently Frequency offset (1 MHz) Jamming signal Frequency Desired channel -89 dBm Simple FM, wide bandwidt h: 0dB CC2500 performance: 31dB Jammer is 1259 times stronger than the wanted signal Selectivity 31 dB ~ 36 times the distance

10 Definitions RF Systems Introduction to digital communication Radio Frequency: Spectrum Tools Agenda

11 Typical Decision Parameters Highest Data Rate WLAN/UWB (Video) CC8520 wireless audio Bluetooth (Audio) Highest Battery Life –CC430/SimpliciTI –ZigBee/ –Bluetooth Low Energy –ANT+ Longest Range –CC112x based Sub1GHz solutions –CC430/CC1101 based Sub1GHz solutions

12 RF-IC –Transmitter/Reciever –Transceiver –System-on-Chip (SoC); typically transceiver with integrated microcontroller Crystal –Reference frequency for the LO and the carrier frequency Balun and Matching –Balanced to unbalanced –Impedance matching circuit Filter –Used if needed to pass regulatory requirements / improve selectivity Antenna Basic Building Blocks

13 Typical RF-IC block diagram 16 bit ULP MCU running from ROM =>new performance features: RX sniff mode, eWor 90dB dynamic range ADC => Enables filtering of strong interferers with accurate digital filters Ultra low phasenoise synth => Full RF regulatory compliance Full digital signal processing =>stable performance over temperature, voltage and process variation

14 Provides reference frequency for Local Oscillator (LO) and the carrier frequency Important characteristics: –Price, often a price vs. performance trade-off –Size –Tolerance[ppm], both initial spread, ageing and over temperature Crystals

15 Crystal Accuracy Compromise between RF performance and crystal cost Receiver channel filter BW Frequency offset 0-2·X ppm+2·X ppm Total error of 4·X ppm Less expensive crystals can be used IF the system employs a frequency calibration / correction

16 Balun and Matching circuit There are different balun implementations –Trade-off: PCB area versus cost Microstrip delay line IC balun Discrete balun

17 PCB antennas –Little extra cost (PCB) –Size demanding at low frequencies –Good performance possible –Complicated to make good designs Whip antennas –Expensive (unless piece of wire) –Good performance –Hard to fit in may applications Chip antennas –Expensive –OK performance –Small size Antennas, commonly used

18 Definitions RF Systems Introduction to digital communication Radio Frequency: Spectrum Tools Agenda

19 Wireless Communication Systems

20 Modulation Methods Starting point: We have a low frequency signal and want to send it at a high frequency Modulation: The process of superimposing a low frequency signal onto a high frequency signal Three modulation schemes available: 1.Amplitude Modulation (AM): the amplitude of the carrier varies in accordance to the information signal 2.Frequency Modulation (FM): the frequency of the carrier varies in accordance to the information signal 3.Phase Modulation (PM): the phase of the carrier varies in accordance to the information signal

21 Digital Modulation – ASK Amplitude Shift Keying (ASK/OOK): Pros: simple, duty cycling (FCC), lower transmit current Cons: susceptible to noise, wide spectrum noise Rise and fall rates of the carrier's amplitude can be adjusted to reduce the spectrum noise at low to medium data rates. –This is called Shaped OO Common Use: Many legacy wireless systems Signal Space Diagram Each axis represents a ‘symbol’ OOK has two symbols: carrier & no carrier Distance between symbols predicts BER 1 0 OOK 1 0 ASK Vm(t) PA vcc AM = analog message Vm(t) ASK/OOK = digital message Vm(t)

22 Amplitude Modulation (lab) Amplitude Modulation –915MHz, 10kHz modulation sine wave 22 AM– 50% in Time Domain AM– 50% in Frequency Domain

23 AM modulator (sim) 250kbps OOK modulation –99% OCBW = 1754kHz –90% OCBW = 229kHz –Average TX current = 50% –ACI = ~50dBc (1MHz off)

24 Frequency Shift Keying (FSK): –Pros: Less susceptible to noise –Cons: can take more bandwidth/bit than ASK –Popular in modern systems –Gaussian FSK (GFSK) has better spectral density than 2-FSK 1 0 Signal Space Diagram / Signal Constellation Each axis represents a ‘symbol’ Each basis function is ‘orthogonal’ Distance between symbols predicts BER Voltage Controlled Oscillator Vm(t) PA Digital Modulation - FSK

25 Frequency Modulation (lab) Frequency Modulation - 25 FM – Freq Domain Waveform at m=0.2 FM – Time Domain Waveform FM – Freq Domain Waveform at m=2 FM – Freq Domain Waveform at m=10

26 FM modulator 250kbps 2FSK modulation –99% OCBW = 508kHz –90% OCBW = 268kHz –Average TX current = 100% –ACI = ~57dBc (1MHz off)

27 4 level FM modulator 250kbps 4FSK modulation –99% OCBW = 321kHz –90% OCBW = 215kHz –Average TX current = 100% –ACI = ~55dBc (1MHz off)

28 Digital Modulation - nFSK Various types of Frequency Shift Keying modulation 28 FSK – Time Domain Waveform 2FSK 4FSK GFSK

29 Quadrature Phase Shift Keying –Pros: Symbol represents two bits of data –Cons: Phase in the signal can jump as much as 180 O causing out of band noise –Offset Quadrature Phase Shift Keying –Pros: Offsetting the signal limits the phase jump to no more than 90 O –Example: IEEE / ZigBee ase-shift_keying Digital Modulation – QPSK/OQPSK

30 OQPSK modulator 250kbps OQPSK modulation –99% OCBW = 4720kHz –90% OCBW = 3072kHz –Average TX current = 100% –ACI = ~30dBc (5MHz off)

31 Comparison of Simulation to real data The modulation, bit rate, frequency deviation are exactly the same in simulation and on a CC1101 device –4FSK on the left (limited by modulation accuracy) –2FSK on the right (limited by noise floor in output)

32 Summary of modulation analysis If we compare the 99% OCBW to the achieved bit rate you get a measure of spectral efficiency. –Zigbee OQPSK is worst because it uses a spreading of 8 –No surprising 4GFSK is best at almost “1” ModulationBit rate (Symbol) Duty cycle 90% OCBW 99% OCBW Bits/Hz (99%) ASK250K (250K)50%229K1754K0.143 FSK250K (250K)100%268K508K0.492 GFSK250K (250K)100%252K397K FSK250K (125K)100%215K321K GFSK250K (125K)100%180K252K0.992 OQPSK250K (2000K)100%3072K4720K0.053

33 Demodulation Requirements Signal Synchronization methods –Bit synchronization –Byte synchronization Comparison of Signal to noise performance of different modulation methods.

34 The Preamble is a pattern of repeated 1’s and 0’s, which is a representation of the modulation 4 bytes / 8 bytes Which can be used by Receiver to pull Received Signal Strength Information (RSSI) –To trigger a Carrier Sense Flag –To qualify Sync Word to protect from false triggers For data rates less than 500kb/s, a minimum 4 byte Preamble is recommended, at 500kb/s, a minimum 8 byte Preamble is recommended Bit synchronization (Preamble)

35 Data is asynchronous, no clock signal is transmitted. Clock is recovered (trained) with the Sync Word. Received Data Train Expected Sync Word 4 clocks 2 clocks 1 clock Recovered Clock Bit Time Sync Word is 2 Bytes Programmable & can be repeated –default 0xD391: An 8 bit Sync Word can be accomplished by Extending the Preamble with the Sync MSB Byte synchronization (Sync Word)

36 WaveMatch; Advanced DSP Detector We have designed the next generation radios where sensitivty and robustness is not limited by the sync detector! Using state-of-the-art digital signal processing we have designed a highly robust, extremely sensitive waveform detector; WaveMatch WaveMatch detector There are numerous benefits to this technology –Ultra high sensitivity, down to -127dBm at 1.2kbps –Extremely quick settling: 0.5 byte preamble (only needed for gain settling – AGC) including AFC –Immune to noise, will not give false sync from noise –Can also be used as a highly reliable preamble detector SYNC DETECTED  Bit Timing Found  Frequency Offset found  Data Demodulation Start

37 Compare sensitivity of 2FSK-4FSK “Waterflow graph” of a 2FSK and a 4FSK system Each “o” represent a system simulation result – symbols each –Versus Eb/No (dB) Results are –2FSK is between 2-3dB better sensitivity than 4FSK ~3dB ~2dB

38 Definitions RF Systems Introduction to digital communication Radio Frequency: Spectrum Tools Agenda

39 Regulations ISM/SRD Bands

40 United States 315/915MHz 2.4 GHz Europe 433/868MHz 2.4 GHz Japan 426MHz 2.4 GHz Other National Requirements exist Regional Comparisons

41 The 2400– MHz band is available for license-free operation in most countries 2.4 GHz Pros –Same solution for all markets without SW/HW alterations –Large bandwidth (83.5MHz) available, allows many separate channels and high datarates –100% duty cycle is possible –More compact antenna solution than below 1 GHz 2.4 GHz Cons –Shorter range than a sub 1 GHz solution (same output power) –Many possible interferers are present in the band The “World-Wide” 2.4 GHz ISM Band

42 Unlicensed ISM/SRD bands: USA/Canada: –260 – 470 MHz(FCC Part ; ) –902 – 928 MHz(FCC Part ; ) –2400 – MHz(FCC Part ; ) Europe: – – MHz(ETSI EN ) –863.0 – MHz(ETSI EN ) –2400 – MHz (ETSI EN or ETSI EN ) Japan: –315 MHz(Ultra low power applications) – , 449, 469 MHz(ARIB STD-T67) –2400 – MHz (ARIB STD-T66) –2471 – 2497 MHz(ARIB RCR STD-33) ISM = Industrial, Scientific and Medical SRD = Short Range Devices Frequency Spectrum Allocation

43 MHz is the main frequency band The MHz range is also available, but with more limitations The MHz band is covered by FCC CFR 47, part 15 Sharing of the bandwidth is done in the same way as for 2.4 GHz: Higher output power is allowed if you spread your transmitted power and don’t occupy one channel all the timeFCC CFR 47 part covers wideband modulation Frequency Hopping Spread Spectrum (FHSS) with ≥50 channels are allowed up to 1 W, FHSS with channels up to 0.25 W Direct Sequence Spread Spectrum (DSSS) and other digital modulation formats with bandwidth above 500 kHz are allowed up to 1W FCC CFR 47 part ”Single channel systems” can only transmit with ~0.75 mW output power Sub 1GHz ISM Bands

44 Definitions RF Systems Introduction to digital communication Radio Frequency: Spectrum Tools Agenda

45 Development kits Value Line CC110LDK development kit contains –2x TRXEB (new transceiver evaluation board) –2x CC110L EM –1x CC113L EM –1x CC115L EM –All EMs with PCB antennas –Cables and docs –Software needed for one way link & PER test –Easy RF development with SmartRF Studio Value Line 433MHz CC110LEMK- 433 kit contains –2x CC110L EM-433 –1x CC113L EM-433 –1x CC115L EM-433 –Based on existing CC1101 ref design TRXEB with: 2x CC110L EM 1x CC113L EM 1x CC115L EM

46 SmartRF Studio version 7 SmartRF Studio is a PC application to be used together with TI’s development kits for ALL CCxxxx RF-ICs. Converts user input to associated chip register values –RF frequency, Data rate, Output power Allows remote control/configuration of the RF device when connected to the PC via a SmartRF Evaluation Board Supports quick and simple performance testing –Packet RX/TX –Packet Error Rate (PER)

47 SmartRF Studio

48 Getting Started with TI LPRF Questions?

49 Backup

50 LPRF Value Line Tools Introduction Booster pack EM for MSP430 launch pad –Pair of compact CC110L transceiver modules with PCB antenna mounted on PCB board for easy connection to MSP Launchpad –Completely integrated module design –Including RF certification for quickest time to market –Module targeted to be used for development & volume production –Module developed & certified by 3 rd party

51 Antenna reference designs (PCB, Chip and Wire antennas) 13 low cost antennas and 3 calibration boards. Frequency ranges from 136 MHz to 2.48 GHz. See also DN031 CC-ANTENNA-DK Price $49 Antenna Evaluation Kit

52 Mini-Development Kits inexpensive flexible development platform for TI's CC2510Fx RF System-on-Chip solution. CC2510Fx - 26MHz single-cycle 8051 CC2500 RF transceiver - FLASH, RAM, 5 DMA channels, ADC, PWM, UART, SPI, I2S, 4 timers, and 21 GPIO pins. The target board in this kit is very close to a real product and features: - PCB antenna pre-tested for ETSI and FCC compliance - battery holders for 2x AAA or 1x CR2032 coincell operation - footprint for 2.54 mm connector connected to CC2510Fx GPIO pins -2 buttons & 2 LEDs for simple application development - pre-programmed with Link Test for RF range measurement

53 Antenna reference designs (PCB, Chip and Wire antennas) 13 low cost antennas and 3 calibration boards. Frequency ranges from 136 MHz to 2.48 GHz. See also DN031 CC-ANTENNA-DK Price $49 Antenna Evaluation Kit

54 eZ430 – RF2500 Development Tool MSP430F2274 UART to PC Virtual COM MSP430F2274 Debug Chain via TUSBFET

55 Software Stacks Z-Stack - ZigBee Protocol Stack from TIZ-Stack –One of the first ZigBee stacks to be certified for the ZigBee 2006 certification –Supports multiple platforms such as CC2480, CC2431 and CC2520+MSP430 platform –ZigBee 2007/PRO available on CC2530 and MSP430 platform TIMAC –A standardized wireless protocol for battery-powered and/or mains powered nodes –Suitable for applications with low data-rate requirements –Support for IEEE /2006 SimpliciTI Network Protocol – RF Made EasySimpliciTI –A simple low-power RF network protocol aimed at small RF networks –Typical for networks with battery operated devices that require long battery life, low data rate and low duty cycle RemoTI Remote controlRemoTI –Compliant with RF4CE V1.0 –Built on mature MAC and PHY technology –Easy to use SW, development kits and tools All software solutions can be downloaded free from the TI web

56 Packet Sniffer Captures and parses packets going over the air Useful debugging tool for any protocol/SW designer PC Tool available for FREE Supported protocols –SimpliciTI –ZigBee RF4CE –ZigBee 2007/PRO –Generic protocol Hardware required for packet sniffing –CC2430DB –CC1111, CC2511 and CC2531 USB Dongle –SmartRF04EB + CC1110/CC2510/CC2430/CC2530 –SmartRF05EB + CC1110/CC2510/CC2430/CC2530/CC2520

57 Packet Sniffer

58 SmartRF Flash Programmer Use this tool to program an application on a System- on-Chip CC1110, CC1111, CC2510, CC2511, CC2430, CC2431, CC2530, CC2531 Program IEEE addresses on CC2430/CC2530 Can also be used to program MSP430s using either MSP-FET430UIF or eZ430 Emulator Dongle Firmware upgrades on the Evaluation Boards

59 PurePath Wireless Configurator Easy to use tool to configure the behavior of the CC8520 device Configures e.g. audio interface, sample rate, I/O mapping Customize the CODEC register settings Generates a firmware image that can be programmed on the device

60 Probability of bit errors


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