A Bluetooth Scatternet-Route Structure forMultihop Ad Hoc Networks

Yong Liu , Myung J. Lee , and TarYong Liu , Myung J. Lee , and Tarek N. Saadawiek N. Saadawi

2003 IEEE Journal on Selected A2003 IEEE Journal on Selected Areas in Communicationsreas in Communications

speakerspeaker ：： ChiChih WuChiChih Wu

OutlineOutline

IntroductionOverview of Bluetooth TechnologyScatternet-Route Structure and It’s on-Demand Formation

Structure DesignOn-Demand Formation of Scatternet RouteScatternet Scheduling

Performance of Scatternet-RouteSimulation ResultsConclusion

IntroductionIntroduction

[1] Xu and Saadawi, “Does the IEEE 802.11 MAC protocol work well in multihop wireless ad hoc networks?”

The existence of sensing range is typically larger than the usually considered transmission range

IEEE 802.11 cannot solve the hidden terminal and exposed terminal problems in multihop wireless networks

These problems may eventually lead to serious TCP instability and unfairness

IntroductionIntroduction

[2] Specification of the Bluetooth System [Online]

Different piconets employ frequency hopping code-division multiple-access (FH-CDMA) channels to prevent mutual interferences

Bluetooth specification defines a scatternet structure( within a scatternet, two Bluetooth device with their distance larger than their transmission range, but less than their sensing range use different time slot or stay in different piconet without interfering each other )

Hidden terminal 、 Exposed terminal can be eliminated

IntroductionIntroduction

[8] B. Raman et al. , “Arguments for cross-layer optimizations in Bluetooth scatternets”[9] P. Johansson et al. , “Bluetooth:An enabler for personal area networking”

The unnecessary link maintenance wastes plenty of power

Suggest the integration of scatternet link formation with on-demand routing

Overview of Bluetooth TechnologyOverview of Bluetooth Technology

Frequency Hopping Code-Division Multiple-Access (FH-CDMA)

625 µs

Point-to-Point link establishInquiry

Inquiry Scan

Page

Page Scan

Overview of Bluetooth TechnologyOverview of Bluetooth Technology

Inquiry ： 32 frequencies of the inquiry hopping sequences are divided into two 16-hop parts, named A train and B train

A single train must be repeated 256 times

Each train period least 2.56 s

At least three train switches (10.24 s)

Inquiry Scan ： random backoff

Page Scan Interval ： 1.28s ( mode R1)

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s On-Demand FormationOn-Demand Formation

The Differences between “Scatternet-Route Structure” and “Big Scatternet Structure”

Traffic Dependency

Network Coverage

Combination with RoutingScatternet Information ： Data Link Layer

Scatternet Routing

SD

master

relay

slave

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

Structure DesignPossible Structure of The Scatternet Route

Single Role Approach

Double Role Approach

Higher ThroughputLower Delay

Robust to The Network Variations

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

• Structure Design

Serve in four piconets

Serve in three piconets

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s On-Demand FormationOn-Demand Formation

Structure DesignTime frame

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet Route

Like most of the on-demand routing protocolsFloodingRoute-discovery-packet (RDP)Route-reply-packet (RRP)

Flooding-Based Route DiscoveryL2CAP BroadcastLMP BroadcastEID Broadcast

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet RouteL2CAP Broadcast

RDP broadcast in the L2CAP layer

Inquiry

Page

6 * ( 10.24 + 0.64 * 3 ) + ( 10.24 + 0.64 ) = 83.84s

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet RouteLMP Broadcast

Inquiry

Page

7 * ( 10.24 + 0.64 ) = 76.16s

1.25ms

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet RouteEID (Extended ID) Broadcast

The inquiry and page processes

Synthesizer

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet RouteEID Broadcast

Source 、 Destination 、 Upstream BD_ADDR

Upstream clock ， Packet sequence number ， EID type…etc.

At least 182 bits ： EID packet (Type 1 、 Type 2)

ISIs(Inquiry scan intervals5.12s 17.92s2.56s 8.96s0.64s 2.24s

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

On-Demand Formation of Scatternet RouteScatternet Formation

Route Setting

Route-Wide Synchronization

RRP

Scatternet-Route Structure and It’s Scatternet-Route Structure and It’s on-Demand Formationon-Demand Formation

Scatternet SchedulingInitial Visit Period ( IVP )

Visit Neighbors Periodically

Performance of Scatternet-RoutePerformance of Scatternet-Route

Scatternet-Route Throughput n x l( 2 x n x m + syn ) x tf

n ： One relay device each time collect n packet

l ： Packet with the size of lm ： l costs m time framessyn ： Synchronized factor tf ： each time frame has the length tf

Performance of Scatternet-RoutePerformance of Scatternet-Route

Packet number

Device ID

Simulation ResultsSimulation Results

• Destination is set as 3, 6, 9, … , 21

Simulation ResultsSimulation Results

Simulation ResultsSimulation Results

Simulation ResultsSimulation Results

ConclusionsConclusions

• EID scheme can achieve an acceptable route setup delay in multihop ad hoc environment

• The scatternet-route structure can achieve high network utilization and stable route throughput