1. Project: IEEE 802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [TG4a General Framework]
Date Submitted: [January 2006]
Source: [Matt Welborn] Company [Freescale Semiconductor, Inc]
Address [8133 Leesburg Pike Vienna, VA USA]
Voice:[ ],
Re: []
Abstract: []
Purpose: [Provide framework for revision baseline draft]
Notice: This document has been prepared to assist the IEEE 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

2. TG4a Overview
Responsive to PAR: Low complexity & power with precision ranging
Regulatory flexibility: Multiple bands in different band groups tailored to expected regulations around the world
Coexistence: Low PSD + low duty cycle + multiple bands + other features
Scalable performance vs. complexity

3. Baseline Mode – Low Complexity with Robust Performance in Multipath
Single UWB band centered at ~4 GHz
Fc = MHz (based on MHz band spacing)
Hybrid PPM+BPSK modulation
Default preamble
256 symbols of L=31 perfect ternary sequence
Data rate: 851 kbps
Concatenated code
Systematic RS + Systematic convolutional code
Very low complexity Aloha medium access control
Ideal for low duty cycle UWB waveforms
Wide bandwidth (>500 MHz) for precision ranging

4. Spectrum Usage
Provides flexibility for coexistence and regulatory compliance worldwide
4 band groups
1: 3.1 to 4.8 GHz
2: 6 to 10.6 GHz
3: 2.4 ISM band (non-UWB  requires different modulation)
4: 500 MHz
One or more designated operating frequencies within each band group
Each band group has a single mandatory band to minimize complexity but ensure interoperability

5. Modulation and FEC
Extremely low complexity architectures are supported for key applications
Hybrid design to provide scalable complexity and performance
Combined PPM and convolutional coding to support coherent and non-coherent architectures
Provides robust performance even in extreme multipath environments
Systematic FEC codes to allow flexible decoding implementation

6. Pulse Shaping Pulse-based UWB technology allows the use of
Latitude in pulse shape allow implementation to optimize for different issues:
Control spectrum
Improve performance in different areas
Minimize complexity
Baseline pulse is specified
Additional optional modifications are identified
Composite pulse based on linear combination
Chirp & CS  intended to reduce cross-correlation
Phase incoherent pulse [was “chaos”]

7. Precision Ranging Precision ranging capability is provided
MAC layer support:
PHY layer support: variable preamble lengths provided to support channel estimation and multipath correction
Ranging protocols

8. Scalability Extreme multipath conditions High density deployments
Reduced PRF for operation in extreme channels
High density deployments
Multiple codes per operating band
Time dithering for piconet isolation
High processing gain for isolation
Alternate symbol rates to trade off robustness and channel duty cycle