doc.: ieee 802.15-03/270 submission july 2003 liang li, helicomm inc.slide 1 project: ieee p802.15...

July 2003

Liang Li, Helicomm Inc.Slide 1

doc.: IEEE 802.15-03/270

Submission

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [802.15.4 Discussion Report July 03]Date Submitted: July, 2003Source: [Liang Li, Yafei Tian, Chenyang Yang] Company: [Helicomm Inc]Address: [1947 Camino Vida Roble]Voice: [760-918-0856], FAX: [760-918-0338], E-Mail: [[email protected]]

Re: []

Abstract: [Opening report for July 2003 San Francisco meeting]

Purpose: []

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 these viewgraphs becomes the property of IEEE and may be made publicly available by P802.15.

July 2003


doc.: IEEE 802.15-03/270

Submission

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Helicomm Proposal

A Low-complexity UWB modulation and Demodulation Method for Low Data-Rate

WPAN

Liang Li, Yafei Tian, Chenyang YangHelicomm Inc

July 2003


doc.: IEEE 802.15-03/270

Submission

Purpose

• Low cost, low complexity, low power, low rate UWB system.

• Complete energy capture, symbol rate sampling, easy timing.

• No down converter, no RAKE, no EQU, no PLL, no coding.

July 2003


doc.: IEEE 802.15-03/270

Submission

Overview

• The possible benefits as using the UWB in low rate system.

• A proposed low complexity UWB modulation and demodulation method for low-data-rate WPAN.

• Performance results.

July 2003


doc.: IEEE 802.15-03/270

Submission

Possible Benefits

• Multipath energy fading is less than 6dB, thus link margin will be small and transmit power will be reduced 10~30dB.

• UWB signal use 3.1~10.6GHz band, thus the crowed 2.4G band is avoided and less interference will be received.

• UWB pulse duration is very short, so it can be used to do precious location, and this ability is very useful when doing route selection in network organizing.

• Compare with the high-rate UWB system, the low-rate system can cover longer distance.

July 2003


doc.: IEEE 802.15-03/270

Submission

A Proposed low complexity UWB Modulation and Demodulation Method

for Low-data rate WPAN

July 2003


doc.: IEEE 802.15-03/270

Submission

Transmitter Structure

PulseGenerator

bT

PA BPF

• The Data Rate is supposed to be 1Mbps. • The 1st part is a differential encoder, the delay is 1 bit which equals to 1us

when data rate is 1Mbps.

• The 2nd part is a pulse generator, which generate UWB pulse and change its polarity corresponding to the bit value after differential encoder.

• The 3rd part is a power amplifier.• The 4th part is a band pass filter.

July 2003


doc.: IEEE 802.15-03/270

Submission

Pulse Shape

• The occupied bandwidth of the pulse is not very wide and the center frequency of it is below 3.1GHz, so that carrier is required to modulate it to comply with FCC’s spectrum mask.

• Pulse width is 3ns, -3dB bandwidth is 410MHz, -10dB bandwidth is 700MHz.

ns3

μs1

t

July 2003


doc.: IEEE 802.15-03/270

Submission

Receiver Structure (1)The traditional Rake Receiver• The correlator before the ADC is a pulse shape matched filter.

• The part after ADC and before the decision device is a traditional Rake combiner. The information bits will be recovered after the differential decoder.

• In general case, when the maximal 8 path is selected, the performance of the selective Rake receiver is approximate to that of all Rake receiver.

BPF LNA ADC

1

2

N

Correlator…

Channel Estimation

Su

mm

er

Synchronization

DifferentialDecoder

Mixer

July 2003


doc.: IEEE 802.15-03/270

Submission

Receiver Structure (2)

Analog differential demodulation(ADD) receiver:

• The received signal is passed by a band pass filter, a low noise amplifier and an analog delay correlator(multiplier and integrator), where the delay is 1us.

• The transmitted bits will be recovered after sampling and decision.

• The sampling and decision device can be implemented with an 1 bit ADC, the sampling rate is very low, that is just the data rate.

BPF LNA Slicer

bT

July 2003


doc.: IEEE 802.15-03/270

Submission

System Parameters & Link Margin

Information data rate Rb = 1 Mb/sPower spectrum density Sf= -41.3dBm/MHzTx signal –3dB bandwidth B= 410MHzAverage Tx power Pt=Sf*B= -15.2 dBmTx antenna gain Gf= 0 dBiRx antenna gain Gr= 0 dBiCenter frequency fc= 3.6 GHzPath loss at 1 meter L1=20log10(4Pifc/C)) = 43.6 dBRx power at 1m Pr=Pt+Gt+Gr-L1= -58.8 dBmNoise power per bit N=-174+10log10(Rb)= -114 dBmRx Noise Figure Referred to the Antenna Terminal Nf= 7 dBTotal noise power per bit Pn=N+Nf= -107 dBm

Eb/No at 1 meter is Pr-Pn = 48.2 dBEb/No at d meter is 48.2 –20log10(d)dB

July 2003


doc.: IEEE 802.15-03/270

Submission

Performance

0 20 40 60 80 100 12010

-3

10-2

10-1

100

Distance (m)

Pac

ket

Err

or R

ate

(PE

R)

Low Rate UWB : 1Mbps

DBPSK-AWGNDBPSK-CM4ARake-AWGNARake-CM4SRake-8tapSRake-4tapSRake-2tapSRake-1tap

July 2003


doc.: IEEE 802.15-03/270

Submission

Performance

6 8 10 12 14 16 18 20 22 2410

-3

10-2

10-1

100

SNR (dB)

Pac

ket

Err

or R

ate

(PE

R)

Low Rate UWB : 1Mbps

ADD-AWGNADD-CM4ARake-AWGNARake-CM4SRake-8tapSRake-4tapSRake-2tapSRake-1tap

July 2003


doc.: IEEE 802.15-03/270

Submission

Conclusion

With the proposed modulation and transmitter structure, following With the proposed modulation and transmitter structure, following benefits can be obtained with the referenced receivers:benefits can be obtained with the referenced receivers:

• The performance of ADD receiver is comparable to the performance of the 2tap SRake receiver, which can achieve 1% PER at 25m distance, and this performance will definitely meet the requirement of WPAN.

• There will be 5dB deterioration of ADD receiver with respect to the all Rake receiver. However, much lower sampling rate is required in ADD receiver, no accurate timing and no channel estimation is required to completely capture the channel energy. Thus the preamble can be designed rather short.

• No frequency acquisition and tracking is required.

• The coding/decoding modular can be inserted if longer distance is required to be covered. The distance will be doubled if the coding gain is 6dB.

doc.: ieee 802.15-03/270 submission july 2003 liang li, helicomm inc.slide 1 project: ieee p802.15...

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