ieee 802.15 tg3 and sg3a

John R. Barr, April 26, 2002Motorola, the Stylized M, and all other trademarks indicated as such herein are trademarks of Motorola, Inc. ® Reg. U.S. Pat. & Tm. Off.

All other product or service names are the property of their respective owners. © Motorola, Inc. 2001. All rights reserved.

IEEE 802.15 TG3 and SG3a

John R. Barr, Ph.D.Chair, IEEE 802.15.3 Task Group

[email protected] (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: Michael 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– WebMaster: 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

communications 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 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 quality 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 piconet is either far enough apart or on different frequencychannel. 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 piconets and associates with existingpiconet or forms independent, child, or neighbor piconet depending on directives fromhost 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/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 support 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 coordinator 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 between video players/gateways and multiple HD

displays– Home theater– PC to LCD projector– Interactive video gaming

• High 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 networking 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 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 handover



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, 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:• Beacon:

– 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 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 different 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 guard 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 data 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”.

• Additional 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 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 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 address 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 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 hundreds of thousands to billions of pulses/second

• Modulation techniques include pulse-position modulation, binary phase-shift keying and others

Pulse width Inter-pulse spacing: uniform or variable



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 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 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 ISM 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 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 bandwidth 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 characteristics:– 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 Applications:– 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 WorldMobile Home

Network ServicesM.Akahane, R.Huang, S.Sugaya, K.Takamura, Sony Corp.

ieee 802.15 tg3 and sg3a

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