Upload
branden-oneal
View
218
Download
4
Tags:
Embed Size (px)
Citation preview
Presented by: Dr. Khaled A. Ali
Urgency-based MAC Protocol for WSBANs
WiSense Seminar Series
• Introduction• Wireless Personal Area Networks• WSBAN Application Examples• IEEE 802.15.4 MAC Protocol• Urgency-based MAC Protocol for WSBANs• U-MAC Performance Evaluation and
Results• Concluding Remarks
Outline
• Massive deployment of Sensor Networks– Stimulated by numerous industry segments, and government
organizations– Sensors and RFID tags will begin to inhabit every object– Emergence of smart sensors with local intelligence
• Traffic volume increases dramatically– Significant architectural changes to global IT infrastructure is
expected– Process moves to network edge to aggregate and filter traffic– Directional shift in network traffic
Introduction
• Integration of WSNs into 4G Networks– Evolution of current ITU and IEEE standards– Connect sensor world with back-end computing
environments– Enable end-to-end solutions
– Mixed Network Traffic of different priority levels and different bandwidth requirements
Introduction
IP Network
4G network
Sensor Net
2G networ
k
3G networ
k
Phone networ
k
Other network
s
Cellular Net
• WPAN (General Description):– Low-rate: (250 kb/s, 40 kb/s and 20 kb/s data
rates)– Range: 10-20 meters– Low power consumption– Addresses: short 16-bit or long 64-bit– Channels: 16 channels (2450 MHz band) , 10
channels (915 MHz band ) and 1 channel (868 MHz band)
– Access mechanisms: CSMA/CA or Aloha – Reliability : Fully acknowledgement, error checking– Cost: Low cost of deployment– MAC& PHY: IEEE 802.15.4 and IEEE 802.15.4a
Wireless Personal Area Networks
• WPAN (Network Topology):
Wireless Personal Area Networks
FFD (PAN)
RFD
star topology
peer-to-peer topology
• WPAN (Layered Architecture):
Wireless Personal Area Networks
Upper Layers
MAC
PHY
Physical Medium
SSCS
802.2 LLC
• Non-invasive WSBANs:– Monitoring and sensing signals from the human
body for medical applications– Distributed communication over the human
body• Invasive (In-Body) WSBANs:
– Connect implanted medical devices (MICS band) and on-body sensors (ISM band)
– Miniature “Pill camera”• Images and medical data are transmitted to a
central WS• View, edit, archive and e-mail the live video,
images and date• Physician can observe and detect exact
location of suspected “in-body” disorder• Patient data can be sent through the
network to establish a diagnosis and trigger the required actions via actuators
WSBAN Application ExamplePersonal Health Care-mixed data rates
• RFID tag integrated in the watch allows entrance in the conference room
• Presentation can be downloaded from nodes in the room
• Business cards are exchanged by handshake
• Additional information can be displayed by video glasses
• Using microphone/motion sensors the main processing unit becomes aware of the meeting and automatically blocks phone calls
WSBAN Application ExampleBusiness Meeting-mixed data rates
• MAC Sublayer
– Generating Network beacons (PAN) – Synchronization– PAN association and disassociation– CSMA-CA – GTS
IEEE 802.15.4 MAC Protocol
INACTIVE
Beacon
Beacon
CFP(GTS)CAP
CAP- Contention Access PeriodCFP- Contention Free PeriodGTS- Guaranteed Time Slots
• Objectives:– Supporting QoS in WSBANs for medical
applications– Increasing network throughput– Minimizing packet rejection rate– Minimizing power consumption
• Approach:– Star network topology – Controlling the number of packet
retransmission • High priority traffic contend more for the transmission
medium than low priority traffic– Slotted Aloha access mechanism
Urgency-based MAC Protocol for WSBANs
• Traffic Classification– Critical Traffic– Non-Critical Traffic
• Arrival Rate– New Packet Arrival
rate (λ)• Critical packet arrival rate• Non critical packet arrival
rate– Retransmitted packet
arrival rate (λr)• Retransmission
Queues
Urgency-based MAC Protocol for WSBANs
U-MAC Block diagram
C1
C2
C3
Cr
λ λ + λr
Channel
Success
Collision
• Packet Transmission Scenario:– Number of critical packet retransmission s; rc=
3– Number of non critical packet
retransmissions ;rnc= 2
Urgency-based MAC Protocol for WSBANs
Pc
Pnc
3 2
rc rnc
2 11 0
• Beacon frame enabled Star network topology
• RFD nodes communicate with a single FFD
• RFD nodes composed of critical nodes and non critical nodes
• Critical nodes contend for the medium rc times
• Non critical nodes contend for the medium rnc times
U-MAC Performance Evaluation and Results
• Maximum number of Critical Nodes• Critical Nodes Packet Arrival Rate• Network Throughput
• Maximum Number of Critical Nodes Nc– Aggrigate Packet Arrival rate G=1
– Number of Critical Nodes
U-MAC Performance Evaluation and Results
• Maximum Number of Critical Nodes Nc
(Cont.)– Ntotal=20 G=1– λc=0.05, 0.06– λnc=0.015– rnc= 0, 2, 5– rc= 0- 5
U-MAC Performance Evaluation and Results
• Critical Packet Arrival Rate– Ntotal=20, Nc=5 G=1– λnc=0.015– rnc= 0, 2, 5– rc= 0- 5
U-MAC Performance Evaluation and Results
• Network Throughput– Critical Nodes Throughput
– Non Critical Nodes Throughput
U-MAC Performance Evaluation and Results
• Network Throughput (Cont.)– Nc=10 Nnc=10 rnc=1 10000 time slots
each of 1 sec.
U-MAC Performance Evaluation and Results
λc =λnc=0.025 λc =λnc=0.03
• An Urgency-Based MAC protocol for WSBAN is proposed
• U-MAC protocol differentiates nodal medium access based of the criticality of the reported traffic
• Critical traffic is allowed to retransmit collided packets more than non critical traffic
• U-MAC protocol performance is evaluated mathematically and through simulation
• The performance results show the ability of the proposed protocol to differentiate network traffic
Concluding Remarks
Thank you