EEE 264-7: Short Range Wireless Networks

1. EEE 264-7: Short Range Wireless Networks

2. IEEE802.15 AND RELATED ORGANIZATIONS

3. What is Wi-Fi • Wi-Fi or Wireless Fidelity is a trademark of the Wi-Fi Alliance for certified products • Based on the IEEE 802.11 standards • The term Wi-Fi is often used by the public as a synonym for wireless LAN (WLAN) • Wi-Fi is supported by personal computer operating systems, game consoles, laptops, smartphones, printers, and other peripherals

4. What is Wimax • WiMAX, Worldwide Interoperability for Microwave Access • Also called Broadband Wireless Access • Uses a variety of transmission modes, from point-to-multipoint links to fully mobile internet access • Provides 3 Mbit/s wireless broadband speed • Technology based on the IEEE 802.16 standard

5. Wi-Fi system details • Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology and multi-carrier OFDM radio technology • Regulations for unlicensed spread spectrum enabled the development of Wi-Fi • Unlicensed spread spectrum was first made available in the US by the Federal Communications Commission (FCC) in 1985

6. Wi-Fi system advantages • Wi-Fi allows low-cost wireless local area networks (LANs) to be deployed client devices • The price of chipsets for Wi-Fi continues to drop • Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world • Wi-Fi is widely available in more than 50 million public hotspots in homes, corporate and university campuses worldwide

7. Wi-Fi system challenges • Spectrum assignments and operational limitations are not consistent worldwide • Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g has a range of 32 m (120 ft) indoors and 95 m (300 ft) outdoors • High power consumption of Wi-Fi makes lower battery life mobile devices.

8. Wi-Fi system devices • Wireless access point (WAP) connects a group of wireless devices to an adjacent wired LAN • Wireless adapters allow devices to connect to a wireless network, such as PCI, miniPCI, USB, ExpressCard, PC card • A wireless router allows wired and wireless Ethernet LAN devices to connect s cable modem or DSL modem • Wireless network bridges connect a wired network to a wireless network such as between two separate homes.

9. OSBRiDGE 3GN - 802.11n Access Point and UMTS/GSM Gateway

10. USB wireless adapter

11. Embedded serial-to-Wi-Fi module

12. City Wide Wi-Fi • Many cities around the world announced plans for a city wide Wi-Fi network • Most of these projects were either canceled or placed on indefinite hold. • A few were successful, for example in 2005, Sunnyvale, California became the first city in the United States to offer city wide free Wi-Fi

13. Wi-Fi Alliance • The Wi-Fi Alliance is a consortium of separate and independent companies • The Alliance aims to improving the interoperability of wireless local area network products based on the IEEE 802.11 standards • The Alliance have a set of common interoperable products based on the family of IEEE 802.11 standards • The Wi-Fi Alliance certifies products via a set of defined test-procedures

14. WiMAX Applications • Connecting Wi-Fi hotspots to the Internet • Providing a wireless alternative to cable and DSL for broadband access • Providing data and telecommunications services • Providing a source of Internet connectivity as part of a business continuity plan • Providing portable connectivity

15. WiMAX Physical layer • The original WiMAX is based in the 10 to 66 GHz range • 802.16a, updated in 2004 to 802.16-2004, added specifications for the 2 to 11 GHz range • 802.16-2004 was updated by 802.16e-2005 in 2005 • More advanced versions, including 802.16e, also bring Multiple Antenna Support through MIMO (Multiple input-Multiple output)

16. WiMAX MIMO board

17. WiMAX Silicon design • A critical requirement for the success of a new technology is the availability of low-cost chipsets and silicon implementations • Intel Corporation is a leader in promoting WiMAX, and has developed its own chipset • Texas Instruments, DesignArt (now owned by Qualcomm), and picoChip are focused on WiMAX chip sets for base stations • Kaben Wireless Silicon is a provider of RF front-end for WiMAX applications.

18. WiMAX Compared with Wi-Fi • WiMAX uses 802.16 standards provide different types of access, from portable (similar to a cordless phone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.) • Wi-Fi uses unlicensed spectrum to provide access to a network • WiMAX and Wi-Fi have quite different Quality of Service (QoS) mechanisms.

19. ULTRA WIDEBAND (UWB) Wireless system with bandwidth more than 20% of carrier frequency or more than 0.5 GHz (defined by FCC) Evolved from Radar concept Very short duration pulses, typically less than 1 nsec

20. UWB PROPERTIES • Ultra wide Bandwidth • High spatial capacity: bits/sec/m2 802.11b Bluetooth 802.11a UWB range (m) 100 10 50 10 BW (MHz) 80 200 7500 data rate (Mbps) 11 1 54 110 spatial cap (b/s/m2) 1,000 30,000 83,000 2,000,000 • Capacity (or maximum data rate): C, bps C = B log2 (1+ SNR) B = Channel bandwidth, Hz SNR = Signal to Noise radio

21. UWB BASIC CHARACTERISTICS • Relatively simple in transceiver architecture • Transmitter: pulse generator + antenna • Receiver: antenna + LNA + matched filter or correlator + detector • Avoids components like power amp, transmit filter, VCO, mixer, PLL, ref oscillator • Low cost and power consumption • Simple hardware entails low cost and low power consumption

22. Low cost, low power Potential for high capacity Low noise power spectral density Good propagation quantities Multipath resistant, High penetration Regulatory lack of standards Performance and implementation Synchronization and susceptibility to interference Short range (a few meters to a few km) Amount of digital computation PROS AND CONS OF UWB OVER NARROWBAND

23. CHALLENGES IN TECHNICAL AREAS • Susceptible to being unintentionally jammed by traditional narrowband transmitter • Filter matching accuracy • Extreme antenna bandwidth requirements • Accurate timing synchronization for a correlated-based receiver due to short pulse durations • Amount of energy in the multipath components caused by reflections in the channel: Rake receiver is a candidate • Noise from on-board microcontroller

24. UWB APPLICATIONS • Home • Entertainment • Proximity detectors • Tracking • Industrial • Automotive- Vehicular radar • Military • Law enforcement/rescue

25. FCC FREQUENCY BAND • Feb. 2002-Assigned frequency band of 3.1 -10.6 GHz :7.5 GHz bandwidth • To be deployed on an unlicensed basis following rules for emissions of intentional radiators- 802.15.3a • With frequency mask which constrains the transmit power

26. FCC MASK

27. XtremeSpectrum Time Domain General Atomics AetherWire & Location Multispectral Solutions (MSSI) Pulse-Link Appairent Technologies Pulsicom Staccato communications Intel TI Motorola Perimeter players Sony Fujitsu Philips Mitsubishi Broadcom Sharps Samsung Panasonic UWB RELATED INDUSTRIES

28. RELATED ORGANIZATIONS • UWB Working Group • NTIA • published a report analyzing the impact of UWB emissions on GPS and suggested an additional 20-35 dB attenuation beyond the power limits described in the FCC Part 15.209. • Department of Commerce • Department of Defense • FCC • NIST

29. OPTIMAL BASEBAND WAVEFORMS • Gaussian impulse • Monocycle • Polycycle • Doublet

30. ONE EXAMPLE -GAUSSIAN PULSE

31. ANOTHER EXAMPLE -DOUBLET

32. MODULATION SCHEMES • Pulse position modulation (PPM) (or Time-modulated) • Pulse amplitude modulation (PAM) • On-off keying (OOK) • Biphase (or BPSK or antipodal) • M-ary • Spectral Keying (SK)

33. DETECTION • Template • Zero crossing detection • Correlator using coded sequences: cross-correlation peak calculated • Maximal sequence codes • Complementary codes • Time-integrating correlator • Time-domain filtering (matched filtering) • Selective Rake receiver

34. UWB ANTENNA CONSIDERATIONS • Parameters • Broadband: Low Q: low selectivity • Antenna matching: impedance • Gain • Polarization • Antenna efficiency = Pradiated / Papplied • Directivity • Small size • VSWR • Differentiation effect • Antenna can no longer be optimized at the carrier frequency (no carrier in UWB) • Frequency-independent antenna is needed • Requirements of UWB antenna • Two dimensional • Omni-directional field pattern • Small size • Low cost

35. TPYES OF ANTENNAS • Bow-tie • Relatively high input impedance • Requires a matching balun to make it usable with 50 ohm system • Tapered slot • Two dimensional microstrip • Resister loaded dipole • Low gain and low efficiency • Diamond dipole: developed by Time Domain Corp. • Emits a waveform similar to a Gaussian third derivative • 75 % efficiency with about 3:1 VSWR • Discone • High performance • 3-D structure: difficult to manufacture • Bicone • High performance • 3-D structure: difficult to manufacture • Log-periodic • Spiral • Transverse electromagnetic (TEM) horn • Most commonly used for UWB radars • Relatively high gain • Wideband • Unidirectional radiation • Little distortion

36. ANTENNA, ONE EXAMPLE • One example • Time Domain Corp. BroadSpec 102 • Planar antenna • Smaller than a standard business card • Well matched from 1.7-4.5 GHz with max return loss -15 dB and VSWR below 1.5:1 • Dipole like pattern with gain 0-3 dBi • Impedance 50+j0 ohm • Efficiency above 90 %

37. TRANSMITTER STRUCTURE • Antenna • Pulse generator • Clock generator • Control • Power control • Modulator: switch

38. RECEIVER STRUCTURE • Efficient receiver processing • Coherent signal processing • Matched filtering • Use matched filter with processing gain to improve SNR • Analog impulse radio MA receiver (AIRMA) • Digital impulse radio MA receiver (DIRMA)

39. RECEIVER STRUCTURE • Low noise amp • Variable gain amp • Sample/hold • A/D converter • Sampling clock generator • Pulse generator • Template generator

40. FUTURE RESEARCH ISSUES • UWB imaging algorithm • Handling on-chip interference • Computationally efficient ranging algorithms • Interference excision over ultra wide bandwidths • UWB node teaming for long-distance transmission • Efficient pulse shape design

41. ZIGBEE –MAIN FEATURES • Low rate wireless personal area networks (LR-WPAN) • in residential and industrial environments • Connectivity among inexpensive fixed, portable, moving devices • Other home networking attempts: wired and wireless • HomePNA • Homeplug Powerline Alliance • CEA R-7 • HomeRF • Echonet • Wireless for home networking: reduction in installation cost • Internet connectivity • Multi-PC connectivity • Audio/video networking • Home automation • Energy conservation • Security • Relaxed throughput requirements for home automation, security, and gaming • Eliminate complexity of heavy protocol stacks • Needs power consumption • Eliminate to utilize too many computational resources

42. ZIGBEE – TECHNICAL SPECIFICATIONS

43. ZIGBEE -APPLICATIONS • Industrial control and monitoring • Public safety • Sensing and location determination at disaster sites • Automotive sensing • Tire pressure monitoring • Smart badges and tags • Precision agriculture • Sensing of soil moisture, pesticide, herbicide, and pH levels • Home automation and networking • PC peripherals: wireless mice, keyboards, joysticks, low-end PDA’s, and games • Consumer electronics; Radio, TV, VCR’s, CD’s, DVD’s, remote controls • Home automation: heating, ventilation, and air conditioning (HVAC), security, lighting, and control of objects such as curtains, windows, doors, and locks • Health monitoring: sensors, monitors, and diagnostics • Toys and games: PC-enhanced toys and interactive gaming between individuals and groups

44. ZIGBEE NETWORK TOPOLOGY • Star network • Peer-to-peer network (mesh network) PAN cordinator User device