March, 2003 IEEE P802.15-03/140r0

IEEE P802.15

Wireless Personal Area Networks

Project / IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Title / TG3a-STMicro-CFP-Document
Date Submitted / [03 March, 2003
Source / [Didier Helal and Philippe Rouzet]
[STMicroelectronics]
[39 Chemin du Champ des Filles 1228 Geneve Plan-les-Ouates, Switzerland] / Voice: [+41 22 929 58 66 or +41 22 929 58 72]
Fax [+41 22 929 29 70]
E-mail: [,
Re: / [This contribution is a response to IEEE P802.15 Alternate PHY Call For Proposals dated 17 January 2003 under number IEEE P802.15-02/372r8 ]
Abstract / [This document is an executive summary of the proposal submitted by STM for an IEEE P802.15 Alternate PHY based on UWB technique.]
Purpose / [Companion document of the Presentation to be made during March IEEE TG3a session in Dallas, Texas.]
Notice / This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release / The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

STMicroelectronics’ UWB PHY proposal to IEEE 802.15.3 TG3a

Executive summary

This document is a companion document to IEEE P802.15-03/139r0 (proposal presentation) and aims at providing a simplified view of the PHY technical proposal as well as some implementation ideas that show how simple can be the chipset realization.

Modulation and principles

The modulation used for our solution is based on simple Pulse Position Modulation (PPM) techniques combined with flipping of pulses sent in a carrierless way. Multiple PPM are allowed. We suggest that this simple modulation provides maximum flexibility for data rate scalability without any penalty on the implementation complexity. Additionally flipping permits efficient spectrum smoothing (spectral line elimination).

The chosen pulse duration is of about 100 to 150 ps. Each pulse is located in a slot that determines the Pulse Period Repetition (PRP). The chosen PRP ranges from 6 to 12 ns, allowing for a very favorable duty factor. Additional Time hoping (TH) can be provided (though not mandatory) for the data part of the frame. This technique is quite efficient to support close proximity of simultaneously operating piconets.

It is shown that the payload data rate can reach up to more than 480 Mbps. Low Data Rate (LDR) options can be simply added with compatibility with the above principles while maintaining interoperability with the High Data Rate PHY.

This outstanding performance is achieved through a simple channel estimation technique. A training sequence is added to the PHY header. Only TH plus flipping is used for this purpose, which makes the estimation very efficient. A training sequence length of 3 to 6 µs is sufficient, even in complex environment situations.

Demodulation is performed by a match-filtering of the receive pulse with the compound channel response obtained by the channel estimator. Since the channel response is estimated dynamically at the beginning of each new frame, no predetermined pulse shape is assumed by the receiver (which eliminates the need to register a known template). Many positive properties of the system are derived from this characteristic:

-  the receiver takes advantage of multi-path,

-  the transmitted shape can be varied to meet specific regulation (notch filter to avoid specific sub-bands).

-  All forms of pulses can be accommodated – from simple pulses to complex ones used in multi-bands approaches.

It has been verified that very simple and scalable implementation can be built. One example is the one-bit direct sampling technique that perfectly fits the system needs, while allowing a very minimum RF block. The complete architecture matches full CMOS implementation for a single chip solution.

Compliancy with existing MAC IEEE 802.15.3

The PHY described above introduces only very minor adaptations (no modifications but only a few add-ons using existing MAC primitives and procedures).

The most important adaptation is the announcement of approximate Time Of Arrival (TOA) by source devices at the beginning of their CTA. This is used both for channel estimation and precise synchronization.

A free benefit of this precise synchronization is that it the MAC will also support precision localization and tracking.

Performance

The proposed system matches all criteria. Particular advantages are very low power consumption and full data rate scalability.

Submission Page XXX Didier Helal and Philippe Rouzet, STMicroelectronics