IEEE 802.15 TG3 and SG3a.ppt

1、IEEE 802.15 TG3 and SG3a,John R. Barr, Ph.D. Chair, IEEE 802.15.3 Task Group Motorola John.BarrM (847) 576-8706,Leadership,Task Group 3 Chair: John Barr, Motorola Vice Chair: Jim Allen, Appairent Technical Editor: James Gilb, Appairent,Study Group 3a Chair: Rick Roberts, XtremeSpectrum Vice Chair: M

2、ichael Dydyk, Motorola Technical Editor: Kai Siwiak, Time Domain Secretary: Matt Welborn, XtremeSpectrum,IEEE 802.15 Working Group Chair: Bob Heile, Appairent Vice Chair: Jim Allen, Appairent Vice Chair: Ian Gifford, Consultant Secretary: Pat Kinney, Invensys Asst. Secretary: Mike McInnis, Boeing We

3、bMaster: Rick Alfvin, Appairent,HR WPAN (802.15.3) Value Proposition,High Rate WPAN enables multimedia connectivity between portable devices within a personal operating space,WPAN Piconet Architecture,Wireless Personal Area Network A wireless personal area network (WPAN) is a wireless ad hoc data co

4、mmunications system which allows a number of independent data devices to communicate with each other. A WPAN is distinguished from other types of data networks in that communications are normally confined to a person or object that typically covers about 10 meters in all directions and envelops the

5、person or a thing whether stationary or in motion. Piconet A set of devices within a personal operation space operating under the control of a piconet controller (PNC) in order to share a wireless resource. The PNC always provides the basic timing for the WPAN. Additionally the PNC manages the quali

6、ty of service (QoS) requirements of the WPAN.,WPAN Topology,Parent Piconet Controller,Piconet Device,Child/Neighbor Piconet Controller,Piconet Relationship,Peer to Peer Data Transmission,Independent Piconet Controller,Parent and Child/Neighbor piconets share common frequency channel. Independent pic

7、onet is either far enough apart or on different frequency channel. It operates independently of other piconets. Child piconet controller can exchange data with parent piconet controller. Neighbor piconet controller only shares frequency channel.,Unassociated device listens for presence of other pico

8、nets and associates with existing piconet or forms independent, child, or neighbor piconet depending on directives from host controller and presence of other piconets.,802.15.3 Main Characteristics,High Rate WPAN: Short Range (at least 10m, up to 70m possible) High Data rates (currently up to 55 Mb/

9、s, to be increased by SG3a to 100-400 Mb/s) Dynamic Topology: Mobile devices often join and leave piconet Short time to connect (1s) Ad-hoc network with Multimedia QoS provisions TDMA for streams with time based allocations Peer to peer connectivity Multiple Power Management Modes: Designed to suppo

10、rt low power portable devices,802.15.3 Main Characteristics,Low price point, low complexity and small form factor Secure Network: PK authentication (ECC mandatory) Key distribution and management (PK) Shared Key encryption (AES 128) and integrity (data and commands, SHA-2) Ease-of-use: Dynamic coord

11、inator selection and handover Does not rely on a backbone network Designed for relatively benign multipath environment: Personal or home space (RMS delay spread 25ns),802.15.3 Main Applications,Video and audio distribution: High speed DV transfer from a digital camcorder to a TV screen HD MPEG2 betw

12、een video players/gateways and multiple HD displays Home theater PC to LCD projector Interactive video gamingHigh speed data transfer: MP3 players Personal home storage Printers & scanners Digital still cameras to/from kiosk,Qualities of the 802.15.3 MAC,Centralized and connection-oriented ad-hoc ne

13、tworking topology: The coordinator (PNC) maintains network synchronization timing, performs admission control, assigns time for connection between 802.15.3 devices (DEV), manages PS requests, Communication is peer to peer Support for multimedia QoS: TDMA superframe architecture with Guaranteed Time

14、Slots (GTS) Authentication, encryption and integrity Multiple power saving modes (asynchronous and synchronous) Simplicity: All QoS negotiations and flow control handling are done at layer 3 PNC only handles channel time requests Robustness: Dynamic channel selection, TX power control per link PNC h

15、andover,Scalable Security Capabilities,Mode 0 is no security Mode 1 allows the user to restrict access to the piconet User externally specifies which devices (MAC address) are in ACL Can be done with simple open enrollment modes using common button push Mode 2 provides cryptographic authentication,

16、payload protection and command integrity. Mode 3 provides payload protection, command and data integrity as well as cryptographic authentication using digital certificates.The security modes above mode 0 are optional,Superframe Structure,Time-slotted superframe structure consists of 3 sections: Beac

17、on: transmits control information to the entire piconet, allocates resources (GTS) per stream ID for the current superframe and provides time synchronization Optional CAP (CSMA/CA): used for authentication/association request/response, stream parameters negotiation, (command frames) PNC can replace

18、the CAP with MTS slots using slotted Aloha access CFP made of: Unidirectional Guaranteed Time Slots (GTS) assigned by the PNC for isochronous or asynchronous data streams Optional Management Time Slots (MTS) in lieu of the CAP for command frames,Beacon #m From PNC,GTS and MTS Slots,GTSs may have dif

19、ferent persistence Dynamic GTS: position in superframe may change from superframe to superframe (Beacon CTA IE or broadcast channel time Grant command) Pseudo-static GTS (isochronous streams): PNC may change the GTS positions, but needs to communicate and confirm with both Tx and Rx DEVs Variable gu

20、ard times between adjacent slots to prevent collision (clock drift)MTS Open & dedicated MTS: Used for PNC/DEV communication Association MTS Number of MTS per superframe is controlled by the PNC,Quality of Service (QoS),QoS typically defined as the latency required to bound jitter of a continuous dat

21、a stream at a desired rate. Latency can be used to buffer data stream so that effects of non-deterministic transmission times can be reduced. Very small amounts of jitter can be handled by the presentation device. Use of latency to reduce jitter requires higher channel bit rates to “catch up”. Addit

22、ional requirements placed on systems where multiple data streams must be synchronized. Home theater audio distribution to multiple speakers Allocation of channel time (TDMA) the best solution.,2.4GHz PHY,5 selectable data rates: 11, 22, 33, 44, 55 Mb/s 11 Msymbol/s Modulation formats: BPSK, QPSK (no

23、 coding), 16, 32, 64-QAM (8-state Trellis code) 15 MHz channel bandwidth 3 or 4 non-overlapping channels 3 channel mode aligns with 802.11b for coexistence Transmit Power: approximately 8 dBm Coexistence: Compared to 802.11, an 802.15.3 2.4GHz PHY system causes less interference since it occupies a

24、smaller bandwidth and transmits at lower power levels Provides for dynamic channel selection Per link dynamic power control Detects and monitors for active channels and moves,Alternate PHY Study Group (802.15.3a),802.15.3 has created a Study Group to investigate the creation of an alternate PHY to a

25、ddress very high data rate applications Goal of 110Mbps 10 m, 400 Mbps 5 m 1394a, USB2.0 HS cable replacement DV50, DV100, HD DVD, High resolution printer and scanner, fast download speed for MP3 players, digital still cameras Currently reviewing Application Presentations and developing requirements

26、 documents Expect to establish a Task Group in July UWB is a potential candidate for these VHR WPAN applications,What is UWB?,UWB signals are typically modulated pulse trains Very short pulse duration (1 ns) Uniform or non-uniform inter-pulse spacing Pulse repetition frequency (PRF) can range from h

27、undreds of thousands to billions of pulses/second Modulation techniques include pulse-position modulation, binary phase-shift keying and others,Large Relative (and Absolute) Bandwidth,UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum Wider than any

28、narrowband system by orders of magnitude Power seen by a narrowband system is a fraction of the total UWB signals can be designed to look like imperceptible random noise to conventional radios,Narrowband (30kHz),Wideband CDMA (5 MHz),UWB (Several GHz),Frequency,Part 15 Limit,Very Low Power Spectral

29、Density (PSD),FCC limits ensure that UWB emission levels are exceedingly small At or below spurious emission limits for all radios At or below unintentional emitter limits Lowest limits ever applied by FCC to any system Part 15 limits equate to 41.25 dBm/MHz For comparison, PSD limits for 2.4 GHz IS

30、M and 5 GHz U-NII bands are 40+ dB higher per MHz Total emissions over several gigahertz of bandwidth are a small fraction of a milliwatt,Large Fractional Bandwidth,Original FCC UWB definition (NPRM) is 25% or more fractional bandwidth Fractional Bandwidth is the ratio of signal bandwidth (10 dB) to

31、 center frequency: Bf = B / FC = 2(Fh-Fl) / (Fh+Fl) Preliminary FCC rules enable in excess of 100% fractional bandwidths 7.5 GHz maximum bandwidth at 10 dB points Large fractional bandwidth leads to High processing gain Multipath resolution and low signal fading,Multipath Performance,Ultra-wide band

32、width provides robust performance in multipath environments Less severe signal fading due to multipath propagation means fade margin of only a few dB Extremely short pulses enable resolution and constructive use of multipath energy using RAKE receiver techniques,Implications for Applications,UWB cha

33、racteristics: Simultaneously low power, low cost high data-rate wireless communications Attractive for high multipath environments Enables the use of powerful RAKE receiver techniques Low fading margin Excellent range-rate scalability Especially promising for high rates ( 100 Mbps)Candidate Applicat

34、ions: Wireless Video Projection, Image Transfer, High-speed Cable Replacement,Challenges for UWB,Wide RF Bandwidth Implementation In-Band Interference Signal Processing Beyond Current DSP (today requires analog processing) Global Standardization Broadband Non-resonant Antennas,Wireless 1394 Bus,802.15.3/a to interconnect multiple 1394 wireless devices within a room Wireless or wireline bridge to interconnect multiple clusters located in different rooms,Connecting Our World,Mobile,Home,Network Services,M.Akahane, R.Huang, S.Sugaya, K.Takamura, Sony Corp.,