1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [Considerations for Supporting the 802.15.3 MAC Over a UWB PHY] Date Submitted: [September 2002] Revised: [] Source: [Daniel Peters, Roberto Aiello, Naiel Askar, Jason Ellis, Susan Lin, Gopal Racherla, Larry Taylor] Company [General Atomics Inc.] Address [General Atomics- Advanced Wireless Group, 10240 Flanders Ct, San Diego, CA 92121-2901] Voice [(858) 457-8700], Fax [(858) 457-8740], E-mail [jason.ellis@ga.com] Re: [Ultra-Wideband System Design Considerations] Abstract: [UWB technology is characterized by parameters different from narrowband systems. This tutorial analyzes the relevant MAC features as they pertain to PHY selection.] Purpose: [IEEE 802.15.3SGa Tutorial September 10, 2002] 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 or organization. The material in this document is subject to change in form and content after further study. The contributor reserves 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.

2. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 2 General Atomics Advanced Wireless Group Daniel Peters, (Daniel.Peters@GA.com) Roberto Aiello, Ph.D. (Aiello@IEEE.org) Naiel Askar, Ph.D. (Naiel.Askar@GA.com) Jason Ellis, (Jason.Ellis@GA.com) Susan Lin, Ph.D. (Susan.Lin@GA.com) Gopal Racherla, Ph.D. (Gopal.Racherla@GA.com) Larry Taylor (Larry.Taylor@ACM.org) www.ga.com/uwb Considerations for Supporting the 802.15.3 MAC Over a UWB PHY

3. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 3 Tutorials Objectives Highlight the most important features that the MAC expects to be provided by the PHY Compare and contrast narrowband and UWB PHYs only as far as they affect these features Investigate how different UWB approaches will provide necessary support Stimulate dialog and discussion within SG3a Assist PHY selection process

4. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 4 PHY Service Key considerations for UWB PHY include CCA and error reporting CCA: Clear Channel Assessment Reference: 802.15.3 MAC draft 11

5. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 5 MLME Service Another key consideration for UWB PHY is scan and remote scan MLME: MAC Layer Management Entity Reference: 802.15.3 MAC draft 11

6. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 6 Channelization Proakis defines the communications channel as the physical medium that is used to send the signal from transmitter to receiver Channelization is the means of sharing the physical medium between multiple disjoint communications channels Large bandwidth enables short pulses; low duty cycle signaling allows for new types of channels *Source: FCC 02-48, UWB Report & Order, released 22 April 02 AttributeComment FrequencyAt most 15 channels as per FCC* Based on 20% fractional bandwidth or 500MHz TimeSynchronized sequence of discrete pulses May be interleaved if low duty cycle CodeSpreading codesSame as narrowband case HybridCombination of other approaches Channelization Options There are many methods for establishing UWB channels

7. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 7 Clear Channel Assessment Needed for CSMA/CA during the Contention Access Period (CAP) of the superframe Utilized by 802.11 systems to detect a medium- busy signal CCA may be estimated by Energy above a certain threshold Detection of the preamble CCA procedure will be different for UWB systems depending on their channelization Energy is not a good measurement for UWB due to wideband receiver CSMA/CA: Carrier Sense Multiple Access with Collision Avoidance

8. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 8 Synchronization Synchronization critically depends on channelization Utilize PHY preamble for synchronization In a narrowband system needed for –Symbol level timing –Carrier frequency error estimation –Carrier phase estimation for coherent demodulation –Channel sounding and equalization Different for UWB –Frequency and phase estimation may not be required –For time interleaved channels, MAC concept of channel identifiers can only have local scope Careful design of preamble allows compatibility of multiple modulation schemes Different for UWB –Frequency and phase estimation may not be required –For time interleaved channels, MAC concept of channel identifiers can only have local scope Careful design of preamble allows compatibility of multiple modulation schemes

9. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 9 Location Awareness Definition of location awareness –Location awareness is the ability to determine information about the range and perhaps relative location of one device with respect to another Attributes of location awareness –Resolution of measurement Inversely proportional to bandwidth –Accuracy of measurement Proportional to SNR –Time to compute Implications to the MAC –The MAC does not presently support location awareness and the PHY cant support it alone New feature that is currently not supported I wonder whats for lunch?

10. doc.: IEEE 802.15-02/379r0 Submission September 2002 General Atomics- Advanced Wireless GroupSlide 10 Conclusions and Discussion CCA and Channel Scanning are the main PHY Service procedures that require careful consideration UWB PHYs may introduce significant new channel concepts Synchronization and channel naming may require re-evaluation CCA for UWB systems may not be possible without preamble detection Support for location awareness can not be confined solely to the PHY