# Presentation: 276404

## IEEE 802.15 TG3 and SG3a

**John R. Barr, Ph.D.**
**Chair, IEEE 802.15.3 Task Group**
**Motorola**
**John.Barr@Motorola.com   (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 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 piconets 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/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

## 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

## 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: *B**f **= B / F**C **= 2(F**h**-F**l**) / (F**h**+F**l**)*
- 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 World

- Mobile

**Home**

**Network Services**

*M.Akahane, R.Huang, S.Sugaya, K.Takamura, Sony Corp.*