Project: IEEE P Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [TG3a Performance Considerations in UWB Multi-Band] Date Submitted: [May 5, 2003] Source: Naiel Askar Ph.D., Susan Lin, Ph.D., Jason Ellis, General Atomics- Photonics Division, Advanced Wireless Group, Flanders Ct, San Diego, CA , Voice +1 (858) ], Fax [+1 (858) ], Re: [Technical contribution] Abstract: [This technical contribution looks at 2 approaches to UWB Multi- Bands and compares them] Purpose: [Technical contribution to compare 2 approaches to UWB Multi-Bands] Notice: This document has been prepared to assist the IEEE P 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 P

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 2 TG3a Performance Considerations in UWB Multi-Band Naiel Askar, Ph.D. Susan Lin, Ph.D. Jason Ellis

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 3 Outline Definition of UWB Multi-Bands Comparison of 2 Specific UWB Multi-Band Approaches –Fixed Sequencing of Bands –Variable Sequencing of Bands –Comparison Criteria Modulation Energy Capture Pulse Repetition Frequency (PRF) Hardware Architecture Channelization Why we support a fixed sequencing approach!

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 4 UWB Multi-Band Defined The Multi-Band Coalition* defines UWB multi-bands as –Partitioning 7,500 MHz of unlicensed UWB spectrum into multiple bands (3-16 bands) occupying between 500 – 700 MHz TimeFrequency *

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 5 Comparison of Modulations Typically for Fixed Sequencing; BPSK, QPSK and variations of PPM is used on multiple bands for modulation Spectral Keying TM modulation allows varying the sequence of the bands, in addition to potential usage of BPSK or QPSK on each band –Allows encoding more information per band –Lower PRF is possible –High data rates achieved using fewer bands Because the set of allowable symbols increases with the factorial of the number of bands f1 f2 f3 f4 f5 f6 Fixed Sequencing Variable Sequencing (Spectral Keying TM )

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 6 Energy Capture is Primarily a Function of Bandwidth Energy capture is important in severe multipath channels Determined by –Bandwidth of transmitted pulse –Number of Rake arms Energy capture is almost independent of modulation Bandwidth of MHz per band allows capture for a good percentage of energy without severe fading CM1 CM4

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 7 Multi-Band Approach Enables Variable PRF Spectral Keying TM achieves slightly lower PRF than Fixed Sequencing Low PRF –Reduces collisions between successive pulses of same frequency –Enables off periods between transmissions which allow collection of more energy with a serial Rake receiver The variable PRF concept allows the optimization of the transmitted waveform to channel properties and required range

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 8 Example Multi-Band Implementations Serial arm receiver –Suitable for fixed sequence Multi-Band solutions –Can still collect multiple rays from the same band Parallel arm receiver –Suitable for any Multi-Band solution –Allows collection of more signal energy –Needs ability to turn off unused components

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 9 How a Single Arm Receiver Collects Energy Off period between multiple chips can be utilized to collect more energy in all Multi-Band solutions by implementing the variable PRF concept Improvements of range equivalent to 2-4 dB are obtained in some channels

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 10 Multipath Performance Results Show Comparable Results Multiband Performance Results (Wisair Presentation) GA Tentative Multiband Performance Results SK Simulation Results

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 11 Multiple Access for Multi-Band Schemes Multi-Bands have many options for multiple access –Fixed Sequencing Time Frequency Codes FDM CDMA Time Interleaved –Variable Sequencing (SK) FDM Time Interleaved

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 12 Multiple Access Performance Results Wisair Multiple Access Results SK Multiple Access Results

doc.: IEEE /208r0 Submission May 2003 General Atomics – Naiel AskarSlide 13 Conclusions – Fixed vs. Variable Sequencing Multi-Band Coalition has performed extensive performance comparisons for both approaches General Atomics’ conclusion is that the 2 approaches can both yield excellent results We are supporting the Fixed Sequencing approach for a because –It is a more open approach, which is more amenable to including further concepts –It supports early merge activities We are actively contributing to a merged UWB Multi-Band proposal We will continue to develop variable sequence technologies such as Spectral Keying TM for applications outside of a