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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 1

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

Submission Title: [DAA framework for UWB]Date Submitted: [March, 2006]Source: [Bin Zhen, Huan-Bang Li and Ryuji Kohno; Company: National

Institute of Information and Communications Technology ]Contact: Bin Zhen Voice:+81 46 847 5445, E-Mail: zhen.bin@nict.go.jp]Abstract: [DAA framework.]Purpose: [UWB DAA support]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 this contribution becomes the property of IEEE and may be made publicly available by P802.15.

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 2

DAA framework for UWB

by Bin Zhen, Huan-bang Li and Ryuji Kohno

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 3

Agenda for discussion in DOC. 06-0049-00-4a

1. Regulatory issues (1) Necessity of Interference reduction technology, e.g. DAA (2) Introduction and discussion of feasible DAA Doc.06-00133-00-4a (This Doc.) (3) Summary of issues in DAA for regulatory compliance2. Coexistence issues (1) Category of coexistence problem (2) Solution for regulatory requirement, i.e. simple DAA, LDC (3) Definition of LDC: necessary duty cycle in node & PCN etc Doc.06-00134-00-4a (Next Doc.)

Regulatory requirement is to ensure coexistence by reasonable interference reduction technology, e.g. DAA, LDC.

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 4

Feasible DAA with Detect in PHY and Avoid in MAC in DOC. 06-0049-00-4a

PNC

nodeband allocation(b1,b2, or b3 )

PNC

nodeband allocation(b2 or b3)

b1 b2 b3

victim system

frequency

PNC should support a detection (e.g., energy) functionality.

victim systemvictim system

interference

Channel b1 is not assigned.

no interference

with DAAwithout DAA

Without DAA, the UWB and victim system will interfere with each other.

The ranging mode of UWB requesting high SINR.

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 5

DAA in 802.15.4a 15.4a defined basic request/report mechanism to

provide a DAA tunnel (06-0047, Joe Decuir and 06-0049, Kohno, Hara, & Takizawa)– Interference measurement is only mandatory for FFD– Interference information communication between FFD

and coordinator– Interference avoid command from coordinator

Victim detection mechanism (as per 802.11h)– Energy detection– Receive power indication histogram– CCA

Not consider the difference between 4a and 11h

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 6

Framework of DAA Distributed sensing

– Only FFD is required to conduct detection– Multiple clusters with FFD’s in a Piconet

Centralized decision at coordinator

PAN coordinator

FFD, cluster header

RFD, device

Cluster 1

Cluster 2

Cluster 3

Victim report

Avoidance command

PICONET

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Zhen, Li, and Kohno (NICT) Slide 7

Geometry of DAA

Victim receiver

keep-out range

sensing border

Victim transmitter

d

Protection range

interference range

UWB transmitter

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 8

Geometry of DAA (cont.) Protection range

– where victim signal is much stronger than the noise interference introduced by UWB

Interference range– where victim signal is comparable with the noise

interference introduced by UWB and some performance decrease can be find

Keep-out range– where severe victim performance decrease can be

find

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March, 2006 Doc: IEEE 15-06-00133-00-004a

Zhen, Li, and Kohno (NICT) Slide 9

Implications to DAA sensing The UWB interference depends on distance

between victim transmitter and receiver– No problem if victim receiver is in victim dominated

range– UWB transmitter should be out of the keep-out range – DAA sensing range should be larger than keep-out

range Victim-dependent range size At least two-looks for transmission from

transmitter and receiver– it is hard for simple sensor to separate them without

decoding the packets

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Zhen, Li, and Kohno (NICT) Slide 10

Detection dependent upon victim type

Classification of victim systems: from modulation– DS style

• 3a-like MBOA, 3a-like DS-UWB and 4a

– OFDM style• 3a-like MBOA, WiMax (16a), and Japan 4G

– Radar?

Classification of victim systems: from bandwidth– UWB– Narrow band

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Zhen, Li, and Kohno (NICT) Slide 11

Key issues in DAA sensing You cannot see the full victim signal

– Intersected and versatile channel bands– Feature based sensing cannot be used. Only energy

based sensing is possible Different channel busy patterns

– Transient pulse energy filled with noise (<0.1 μs)– Symbol duration of channel busy time (100 μs)

Simple sensor nodes – Computing capacity, complexity, cost, power

consumption Almost no time limitation

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Zhen, Li, and Kohno (NICT) Slide 12

Key issues in DAA sensing (cont.)

Partially overlapped channels

Channel state pattern

MBOA (4488MHz, 528MHz)

4a (4446Mhz, 499.2MHz)

f

16a (10/20 MHz)

t

4a (<0.1μs)

16a (>10μs, OFDM)

MBOA (~0.3μs, FH)

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Zhen, Li, and Kohno (NICT) Slide 13

Expected DAA performance

DAA increases probability of interference among 4a piconets due to less available channels

Distributed DAA sensing– Pd=0.9 with Pfa=0.1 of a FFD

• the pionet detection probability is 0.9, 0.99, 0.999,… when there are 1, 2, 3, … FFD in the piconet;

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Zhen, Li, and Kohno (NICT) Slide 14

DAA sensing mechanism Split a 4a channel into sub-bands

– 4a channels and victim channels are not full overlapped

– Noise signal could dominate channel energy for a narrow band system, especially in low SNR environment.

• Given 500MHz filter for a 20MHz signal, the noise level increase 14dB

Separated band-pass filter bank– 10MHz BPF bank for narrow band victims– 100MHz BPF bank for UWB victims

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Zhen, Li, and Kohno (NICT) Slide 15

DAA sensing mechanism (cont.)

Victim dependent energy detection in both time and frequency domain– Time pattern of energy detection

• Frequency hopping MBOA

– Post-processing• Average, integration, etc.

Step-by-step sensing– Victim, sub-band

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Zhen, Li, and Kohno (NICT) Slide 16

Block diagram of DAA

Matched filer De-spreader Communication& ranging

500MHz BPF

10MHz tunable BPF

Energy

DetectionDAA decision

500MHz BPF(detected channel)

Post-

processing

100MHz tunable BPF

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Zhen, Li, and Kohno (NICT) Slide 17

DAA sensing performance Impact factors of sensing

– Filter bank• Filter bandwidth• Filter center frequency• Distribution of filter

– Detection duration– Multipath channel– SNR

Central decision– Sub-band state decision at FFD– Merge algorithm at coordinator

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Zhen, Li, and Kohno (NICT) Slide 18

Extension of basic request/report Basic request

– inform victim style Basic report

– Split a channel into sub-bands – Report busy probability of each sub-band

• The same channel energy could indicate different states

– Channel energy report is a big traffic

• More than one victim systems in the same channel, e.g. 16a and MBOA.

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Zhen, Li, and Kohno (NICT) Slide 19

New basic request/report format

Channel number

Measurement duration

Basic request

Channel number

Channel energy

Basic report Map field

DS-UWB

Narrow-band OFDM

Radar signal

Channel number

Sub-channel number

Un-measured

Busy probability

(06-0046 from Joe.)

Channel number

Measurement duration

Victim style

MBOA-UWB

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Zhen, Li, and Kohno (NICT) Slide 20

TBD parameters

Busy sub-band sensing– Energy threshold – Time pattern

Optimal filter bank– Center frequency– Filter bandwidth– Filter distribution and density

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Zhen, Li, and Kohno (NICT) Slide 21

Summary Framework of distributed UWB DAA sensing

– DS-UWB style and OFDM style Split a 4a channel into sub-bands for DAA

sensing– 100MHz for UWB victims– 10MHz for narrow band victims

Extension of basic request/report– Busy probability of sub-band

Simple DAA can be accomplished in a sensor node

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Zhen, Li, and Kohno (NICT) Slide 22

Annex 1: UWB victim systems 802.16a

– OFDM receiver threshold: -90 dBm– Unlicensed channel: 10/20 MHz, 256 bands– Downlink pilot: 0xfff

MBOA– Mult-band OFDM receiver threshold: -80 dBm– Channel: 528MHz, 122 bands– Preamble: ….

DS-UWB– 3a-like

• receiver threshold: -90 dBm• Channel: 3.1~4.9 GHz• Preamble: …..

Japan 4G:

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Zhen, Li, and Kohno (NICT) Slide 23

Annex 2: DAA in UWB and spectrum sensing in 802.22

802.22: a developing cognitive radio-based PHY/MAC standard in TV channels– Existing and narrow band systems– No channel intersection issue– Not handhold device and sensor