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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [Staccato UWB PHY Proposal for TG4a] Date Submitted:

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Presentation on theme: "Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [Staccato UWB PHY Proposal for TG4a] Date Submitted:"— Presentation transcript:

1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANS) Submission Title: [Staccato UWB PHY Proposal for TG4a] Date Submitted: [January 2005] Revised: [] Source: [Roberto Aiello, Ph.D., Torbjorn Larsson, Ph.D.] Company [Staccato Communications] Re: [ a Call for proposal] Abstract: [This presentation represents Staccato Communications proposal for the a PHY standard, based on UWB] Purpose: [Response to WPAN a Call for Proposals] 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 January 2005 doc.: IEEE /704r1

2 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 2 Staccato Communications UWB PHY Proposal for TG4a Roberto Aiello, Ph.D. Torbjorn Larsson, Ph.D. Staccato Communications

3 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 3 Goals Good use of UWB unlicensed spectrum Good system design Path to low complexity CMOS design Path to low power consumption Scalable to future standards Graceful co-existence with other services Graceful co-existence with other UWB systems

4 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 4 Introduction Staccato is MBOAs founding member, promoter BOD member This proposal is based on band limited impulse radio OFDM is optimal solution for high performance systems Impulse radio has attractive features for 15.4a applications

5 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 5 Features Meets all system requirements Low signal repetition frequency to reduce ICI/ISI and need for high speed digital circuits (lower power consumption) Narrow UWB bandwidth to reduce complexity Use of differential encoding on chip level to reduce receiver complexity and provide maximum robustness

6 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 6 Summary Band limited UWB system compliant with FCC 02-48, UWB Report & Order 500MHz bandwidth at -10dB Two bands centered at GHz and GHz (MB-OFDM band 4 and 5) Symbol rates varying from 12.5 kbps to 1.6 Mbps at PHY-SAP Due to time constraints, this presentation addresses –Modulation scheme, channelization and packet structure –Performance in AWGN Remaining material will be presented at the next opportunity in March 2005 –Performance in multipath –Implementation feasibility –Self evaluation criteria –Other issues that will emerge from groups feedback

7 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 7 Multipath CM8 (Industrial NLOS) PRF = 3.2 MHz

8 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 8 System Description PRF = 3.2 MHz

9 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 9 System Description, Continued Impulse radio combined with direct-sequence spreading Differential BPSK modulation of chips A code word covers one BPSK-modulated symbol Different piconets use different code words Differential encoding of chips allows the use of differential chip detection in the receiver –Differential detection is carried out separately for each multipath component –Differential combining of multipath components –No need for channel estimation –Simple receiver structure with decent performance

10 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 10 System Description, Continued For improved performance, non-coherent symbol detection (with coherent energy integration across one code word) can be used –Symbol detection is carried out separately for each multipath component –Non-coherent combining of multipath components –Still no need for channel estimation PRF (chip rate): 3.2 MHz –Low enough to avoid interchip interference (ICI) with all a multipath models –High enough to eliminate the need for frequency offset correction (with some performance loss) when differential detection is used Pulse shape: 3rd-order Butterworth or similar FEC: 16-state rate-1/2 convolutional code and symbol repetition

11 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 11 Differential Multipath Combining

12 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 12 System Parameters Length of spreading code in preamble is always 16 Duty cycle < 100% means that code words of length 16 are transmitted with a space in between –An extra initial chip is added to serve as phase reference for the first chip in the code word –For instance, to achieve a duty cycle of approximately 50%, 17 chips are transmitted followed by a space equivalent to 15 chip periods PHR = PHY Header; PSDU = PHY Service Data Unit; SFD = Start-of-Frame Delimiter

13 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 13 Packet Structure

14 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 14 Spreading Codes (Length 16) These code words (c) were found by exhaustive search based on the three following properties: –Low cyclic autocorrelation –Low cyclic cross-correlation between code words c –Low cross-correlation between code words (1,c) and (1,-c)

15 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 15 Throughput The length of the data PSDU (payload) is 32 octets. The data rate is 100 kbps (this is X0 in this proposal) Assumptions (refer to the figure on page 20 in the PHY selection criteria document) –aMinLIFSPeriod = 40 symbol periods –aTurnaroundTime = 12 symbol periods –aUnitBackoffPeriod = 20 symbol periods –Length of ACK PSDU = 5 octets t_ack is the time between the end of the data frame and the beginning of the ACK frame –worst case, is t_ack = aTurnaroundTime + aUnitBackoffPeriod = 32 –best case, t_ack is t_ack = aTurnaroundTime = 12

16 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 16 Receiver Architectures Differential chip detection during acquisition and non-coherent symbol detection during data demodulation Differential chip detection during both acquisition and data demodulation A. B.

17 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 17 More on Receiver Architectures In both architectues, acquisition is based on differential detection/combining –Does not require frequency offset correction and therefore leads to shorter preamble (=> less overhead) –Small performance loss at 20 ppm frequency error –If desired, frequency offset estimation can be carried out in parallel with synchronization Architecture A Differential chip detection for data demodulation –Frequency offset correction may still be applied during PHR and PSDU to improve performance Architecture B. Non-coherent symbol demodulation for data demodulation –Significant performance improvement, since we are now summing energy coherently across a whole codeword (which for data rates <= 100 kbps is 16 chips long) –Requires frequency offset estimation (during acquisition) and correction (during data demodulation)

18 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 18 Link Budget

19 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 19 System Simulation Parameters Frequency band: 4.752GHz (MB-OFDM band 4) 10 dB bandwidth: 500 MHz Transmit power: dBm Transmit/Receive filter: 3rd order Butterworth, corner frequency 180 kHz A/D converter: 528 MHz, 3 bits Noise figure: 7 dB Data rate: 100 kbps PSDU size: 32 bytes PRF (chip rate): 3.2 MHz Length of DS spreading code: 16 Length of preamble: 48 bits Length of SFD: 32 bits Length of PHR: 48 bits Modulation: DBPSK Demodulation method: differential detection No frequency offset

20 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 20 Spectrum TX Power: dBm

21 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 21 PER vs. Distance in AWGN (100 kbps)

22 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 22 PER vs. Eb/No (100 kbps)

23 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 23 PER vs. Received Power (100 kbps)

24 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 24 Conclusions UWB band limited system Meet all system requirements Low signal repetition frequency to reduce ICI and need for high speed digital circuits (lower power consumption) Narrow UWB bandwidth to reduce complexity Remaining material will be presented at the next opportunity

25 doc.: IEEE /704r1 Submission January 2005 Roberto Aiello, Staccato CommunicationsSlide 25 Staccato Communications is actively collaborating with others Objectives: Best Technical Solution ONE Solution Excellent Business Terms Fast Time To Market We encourage participation by any party who can help us reach our goals a Early Merge Work


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