ultra wide band body area network

ULTRA WIDE BAND WIRELESS BODY AREA NETWORKS

Guide: Dr.Lillykutty Jacob Presented By:

Aravind M.TM.Tech II SemDept.of ECENITC

CONTENTS OF THE PRESENTATION

Objective /Goals

Introduction

Why BAN?

Why UWB?

Basic Requirements

Topology

Existing System

Proposed System

Propagation Channel Model

MAC Algorithm

Conclusion

References

9 February 2017 2Dept. of ECE , NITC

GOALS

Understanding UWB-BANs.

Appreciating their ‘potency’.

Being aware of their current applications .

Understanding the challenges on the horizon.

Understanding proposed models.

Understanding various topologies.


INTRODUCTION

Increasing population and the rising costs of health care have triggered the introduction of novel

technology-driven enhancements to current health care practices.

Recent advances in electronics have enabled the development of small and intelligent (bio-)

medical sensors which can be worn on or implanted in the human body.

Thus introduced Wireless Body Area Network (WBAN).

Wireless body area network (WBAN) is a collection of wireless sensors placed around or in a

human body that are used to collect important information wirelessly.

Recently, ultra-wideband (UWB) wireless technology is used for wireless body area network

(WBAN) applications.

Benefits : low-power transmitter, low radio frequency (RF) and electromagnetic

interference effects in medical environment, small size antenna and high data rate.


What is BAN…???

Definition by IEEE 802.15.6:

“A communication standard optimized for low power devices for

their operation on, in or around the human body (but not limited to

humans) to serve a variety of applications including medical,

consumer electronics or personal entertainment and other.”


What is UWB…???

Ultra wideband (also known as UWB or as digital pulse wireless) is

a wireless technology for transmitting large amounts of digital data

over a wide spectrum of frequency bands with very low power for a

short distance.


http://searchmobilecomputing.techtarget.com/definition/wireless

http://searchcio-midmarket.techtarget.com/definition/frequency

http://searchcio-midmarket.techtarget.com/definition/power

Basic requirements of a WBAN

Limited transmission range .

Extremely low power consumption in sleep mode.

Support of scalable data rate ranging from 1kbps to several Mbps.

QoS support for critical physiological data.

Low latency over a multi-hop network.

Small form factor and light weight devices.


ADVANTAGES & DRAWBACKS - UWB

Advantages:

Usage of IR-UWB

Pulse Based Nature-Simpler Modulation Scheme

Power Saving

Less hardware Complexity

High data rate

Drawbacks:

Receiver Complexity


EXISTING SYSTEM-RESEARCH CHALLENGES

1.Frequency Band Selection:

1. Most BAN devices need global operability.

2. Facility for low-power usage (less crowded).

3. Less stringent rules for flexible usage and adaptability.

4. Solutions proposed: Use UWB standard ,an operational bandwidth from

wide spectrum ranges from 3.1-10 GHz.

` 9Dept. of ECE , NITC

2. PHY Protocol Design:

1)Minimize power consumption.

Solution: Quick turn-around from transmit to receive and fast wake-up from sleepmode.

3. Energy-Efficient Hardware:

1. Today’s wireless technologies draw relatively high peak current.

2. Also rely on duty cycling between sleep and active.

Solution: Operation on low peak pulse-discharge current from thin-film (paper)

batteries, idle listening.

EXISTING SYSTEM-RESEARCH CHALLENGES CONTD…


4. Technical Requirements:

1. Wide variation in data rate, BER, delay tolerance, duty cycle and lifetime.

2. Diverse application environments.

5. Security

1. More resource-efficient and light weight security protocols.

EXISTING SYSTEM-RESEARCH CHALLENGES CONTD…


Focuses upon:

1. Rate adaptable MAC protocol for UWB .

2. A preamble sampling multiple access protocol for UWB network.

3. A transmit-only MAC protocol.

PROPOSED SYSTEM


Topology of WBAN for a multi-human monitoring environment


A DUAL BAND (UWB-TRANSMIT AND NARROWBAND-RECEIVE) APPROACH FOR WBAN

Communication protocols for WBAN (a) transmitter and receiver both use UWB (b) UWB transmit-only (c) mixed band


UWB AND NARROW BAND PHYSICAL LAYER

IR-UWB pulse generation


UWB NARROW BAND PHYSICAL LAYER

Propagation channels involved


Path loss at a distance ‘d’ can be calculated as;

P dB(d)=P0,dB+a(d/d0)n + N(µ(d), σ2(d))

d depth from skin in millimeters

d0 reference distance

P0, dB Path loss at reference distance

a Fitting Constant

n Path Loss Exponent

PROPAGATION CHANNEL MODEL


Average path loss(L) of IR-UWB signals at a distance of ‘d’ is given by,

fc (fmin*fmax )1/2

fmin & fmax -10dB edges of the waveform Spectrum.

c Velocity of Light

d Distance relative to 1m reference point

PROPAGATION CHANNEL MODEL CONTD…

L1 = 20 log (4 π fc/c) , L2=20 log (d) and L=L1+L2


UWB –PULSE MODULATION SCHEME

BPPM (Binary Pulse Position Modulation)

Two mechanisms to ensure transmit power effectively

1. Use Gated Pulse Transmission Scheme.

2. Dynamically Varying Pulse per Bit Scheme.


UWB –PULSE MODULATION SCHEME Contd…

(a) two PPB and (b) three PPB in BPPM.


POWER LIMITATIONS OF THE GATED UWB PULSE TRANSMISSION

Full bandwidth (FBW) peak power of UWB signal is 1mW for low PRF systems.

Assumed resolution BW ,1 MHz

PRF for proposed UWB based WBAN sensor node is 100MHz, which is high.

Hence considered High Pulse Repetition Frequency System.

Ppeak <= 7.5x10-8 (Bp/R)2 x 1/𝛿 W

Ppeak <= 0.001(BR/50 x 106)2 x (Bp/R)

2 W

Bp = 1/ T , T is Pulse Width

BR = Resolution Bandwidth

R = Pulse Repetition Frequency

𝛿 = Duty Cycle


Variation of full bandwidth peak power with duty cycle


BER Analysis of Multiple PPB Scheme

IR-UWB receiver model

n(t) if there is no pulse present in a time time slot

r(t) = s(t)+n(t) if there is a pulse present in a time slot

nB(t) if there is no pulse present in a time time slot

r’(t) = sB(t)+nB(t) if there is a pulse present in a time slot


BER ANALYSIS OF MULTIPLE PPB SCHEME


BER ANALYSIS OF MULTIPLE PPB SCHEME

Considering MAI and MPI ,modified form of Probability of Error for Single Pulse

Detection of the Receiver with BPPM Modulation Scheme

Pe=Q √(Ep/N0)2/2 (Ep/N0+TsB+M)

N(0,M) --------- Interference Distribution


Bit error rate (BER) Vs. pulse Ep/No (dB) curves for different number of PPB


Super Frame Structure and Timing


MAC ALGORITHM

9 February 2017 Dept. of ECE , NITC 28

Turn on

Waits and receive beacon on the NB channel and synchronizes

super frame structure

Sends RTS(Preamble Sequence + sensor ID) in one of the first two time slots of the CAP

Listens to the CTS on NB Channel

CTS Received?

End of Initialization

Waits Random Back off timeNo

Parent Node sends CTS Message

Yes

MAC ALGORITHM Contd…


Data to send

Waits and receive beacon on the NB channel and synchronizes

super frame structure

Sends data in a previously assigned GTS using assigned

PPB

Parent Node determines the Bit Error Rate and whether a PPB

change is required

PPB changed ?

Go to Low Power Mode

Data to send=Previous Data Yes

MAC ALGORITHM Contd…


Data to send

Sensor Initialization (starts from position in a)

Waits and receive beacon on the NB channel and synchronizes super frame structure

Sends data in a previously assigned PDS using assigned PPB

PPB changed?

Parent node sends ACK

Data to send=Previous Data

Parent Node determines the Bit Error Rate and whether a PPB change is required

Ack rcvd?

Discards Packet from memory , stores the last assigned PPB and go to Low power mode.

Waits Random Back off time.

N

Y

Network Topologies used in Simulations


PERMORMANCE PARAMETERS…

PER PULSE TRANSMIT POWER ALLOCATION (PPTP)

CRUCIAL FACTOR IN DETERMINING THE PULSE SIGNAL TO NOISE RATIO

PPTP= FBW TRANSMIT POWER / DUTY CYCLE * PRF


PERMORMANCE PARAMETERS CONTD…

NORMALIZED THROUGHPUT(%)

R(bps)/C(bps)x100%

R Total Data Bit Rate

C Total Network Capacity

PACKET LOSS RATIO

PL=L/S

PL Packet Loss

L Total No: of Lost Packets

S Total No: of Send Packets



PERMORMANCE PARAMETERS CONTD…

E(J/bit)=(( 𝑖=0𝐾 (𝐼 𝐴 ∗ 𝑉 𝑉 ∗ 𝑇𝑡𝑥 − 𝑟𝑥 𝑠𝑒𝑐 )/ 𝑖=0

𝐾 B)

D=T1-T2

E(J/bit) Consumed Energy at a Sensor Node per useful data bit.

I(A) Consumed current of Sensor Node.

V(V) Battery Voltage.

Ttx-rx (sec) sum of Transmission time per data packet and reception time for ack’s.

B Total no: of useful bit.

K Total no: of packet sent.

D Packet Acknowledgement Delay for Periodic Traffic.

T1 Actual Time at which packet is acknowledged.

T2 Time at which packet enters the Transmission Queue.

VARIATION OF AVERAGE PACKET LOSS RATIO WITH THE INCREASE OF NUMBER OF SENSORS


Average Packet Acknowledgement Delay

Variation of the average packet acknowledgement delay (seconds)for periodic traffic with increasing number of sensor nodes for twotopologies with and without narrow band feed back


PERCENTAGE THROUGHPUT

Variation of the percentage throughput for each sensor type in the two simulated topologies


ENERGY CONSUMPTION

Variation of consumed energy by a sensor node per useful databit (in nJ) with increasing number of sensor nodes for twotopologies and for sensor nodes with narrowband receivers andsensor nodes with UWB receivers.


Comparison with Existing MAC Protocols…TABLE 5


CONCLUSION

Ultra-wide band wireless technology does not present an EMI risk to other narrow band

systems since its transmitter power is quite low and the frequencies used are at very high

frequencies.

Dual band is proposed for WBAN sensor nodes to achieve a power consumption while

maintaining a good QOS.

Using a router as an intermediate node improves the data transmission within a WBAN.

Minimizes the power consumption and packet delays for a UWB-based WBAN sensor node

using a narrow band receiver.

Lower transmission power will increase the battery lifespan of the WBAN sensor nodes.


REFERENCES

1) Kasun M. S. Thotahewa, Jamil Y. Khan, Mehmet R. Yuce, “Power Efficient Ultra Wide Band Based Wireless

Body Area Networks with Narrowband Feedback Path”, IEEE TRANSACTIONS ON MOBILE COMPUTING,

VOL. 13, NO. 8, AUGUST 2014.

2) K.M.S. Thotahewa, J.-M. Redoute, M.R. Yuce, “Medium access control (MAC) protocols for ultra-wideband

(UWB) based wireless body area networks (WBAN), ultra-wideband and 60 GHz communications for biomedical

applications”, ISBN: 978-1-4614 8895-8, Springer, 2013.

3) Chee Keong Hoa, Terence S.P. Seeb, Mehmet R. Yucec, “An ultra-wideband wireless body area network:

Evaluation in static and dynamic channel conditions” Sensors and Actuators A 180 , 137– 147,ELSEVIER 2012.

4) Hiroki Katsuta 1, Yuichiro Takei 1, Kenichi Takizawa2, Tetsushi Ikegami , “Experiments of Ultra Wideband-

based Wireless Body Area Networks with Multi-Nodes Attached to Body”, IEEE 2014.


REFERENCES

5. L. Huan-Bang and R. Kohno, “Introduction of SG-BAN in IEEE 802.15 with related discussion,” in Proc.

IEEE ICUWB, pp. 134–139, Sep. 2007.

6. Yuichiro TAKEI, Hiroki KATSUTA, Kenichi TAKIZAWA, Tetsushi IKEGAMI, Kiyoshi HAMAGUCHI,

“Prototype Ultra Wideband-based Wireless Body Area Network -Consideration of CAP and CFP slot

allocation during human walking motion” 34th Annual International Conference of the IEEE EMBS San

Diego, California USA, 28 August - 1 September, 2012.

7. Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate

Wireless Personal Area Networks (LR-WPANs), IEEE Standard 802.15.4-2006, 2007.

8. www.zigbee.org.


ultra wide band body area network

Engineering