Modeling & Simulation Modeling & Simulation of Bluetooth MAC of Bluetooth MAC

protocolprotocolCOE543 Term ProjectCOE543 Term Project

Spring 2003Spring 2003

Submitted by:Submitted by:H.M.Asif (ID# 230457)H.M.Asif (ID# 230457)

Outlines:Outlines:

Bluetooth overviewBluetooth overview The Bluetooth StackThe Bluetooth Stack Bluetooth MAC protocolBluetooth MAC protocol Simulation design and AssumptionSimulation design and Assumption ResultsResults Future workFuture work ConclusionConclusion

Bluetooth overview:Bluetooth overview:

What is Bluetooth?What is Bluetooth? Why Bluetooth?Why Bluetooth? Bluetooth HistoryBluetooth History Bluetooth Network TopologyBluetooth Network Topology

What is Bluetooth?What is Bluetooth?

Cable replacement technology Cable replacement technology primarilyprimarily

Bluetooth wireless technology is an Bluetooth wireless technology is an openopen specification for a specification for a low-costlow-cost, , low-powerlow-power, short-range radio , short-range radio technology for technology for ad-hocad-hoc wireless wireless communication of communication of voice and datavoice and data anywhereanywhere in the world. in the world.

Cont’d:Cont’d:

Bluetooth uses a frequency-hopping scheme Bluetooth uses a frequency-hopping scheme in the unlicensed Industrial Scientific-in the unlicensed Industrial Scientific-Medical (ISM) band at 2.4 GHz. Medical (ISM) band at 2.4 GHz.

The major goal with the Bluetooth wireless The major goal with the Bluetooth wireless technology is to allow relatively cheap technology is to allow relatively cheap electronic devices to communicate directly electronic devices to communicate directly in an in an ad-hoc fashionad-hoc fashion, Moreover, the , Moreover, the Bluetooth equipped devices can also form Bluetooth equipped devices can also form networks– such a network of personal networks– such a network of personal devices is often referred to as a devices is often referred to as a personal personal area network (PANarea network (PAN).).

Why Bluetooth?Why Bluetooth?

Cable replacement between devices.Cable replacement between devices. Open SpecificationOpen Specification Low power consumptionLow power consumption Devices can be connected to multiple Devices can be connected to multiple

devices at the same time. devices at the same time. Operate in Un-licensed band (2.4GHz Operate in Un-licensed band (2.4GHz

ISM)ISM)

Bluetooth Technical Bluetooth Technical Features:Features:

2.4 GHz ISM Open Band2.4 GHz ISM Open Band Globally free available frequencyGlobally free available frequency 79 channels (2400-2483.5 MHz ISM band)79 channels (2400-2483.5 MHz ISM band) Frequency Hopping & Time Division Duplex (1600 hops/second Frequency Hopping & Time Division Duplex (1600 hops/second

typically)typically) 10-100 Meter Range10-100 Meter Range

Class I – 100 meter (300 feet)Class I – 100 meter (300 feet) Class II – 20 meter (60 feet)Class II – 20 meter (60 feet) Class III – 10 meter (30 feet)Class III – 10 meter (30 feet)

Link Rate : 1 MbpsLink Rate : 1 Mbps Simultaneous Voice/Data Capable Simultaneous Voice/Data Capable

SCO (Synchronous connection oriented) for voice SCO (Synchronous connection oriented) for voice ACL (Asynchronous connectionless link) for dataACL (Asynchronous connectionless link) for data

Transmit Power: 0dbm Transmit Power: 0dbm Receiver Sensitivity : -73dbmReceiver Sensitivity : -73dbm Uses Binary GFSKUses Binary GFSK

Bluetooth History:Bluetooth History:

King Harold Blatand, or Bluetooth, a King Harold Blatand, or Bluetooth, a Viking and King of Denmark 940-981, Viking and King of Denmark 940-981, united Denmark & Norwayunited Denmark & Norway

1994 – Ericsson study on a wireless 1994 – Ericsson study on a wireless technology to link mobile phones and technology to link mobile phones and accessoriesaccessories

Bluetooth history Bluetooth history (cont’d):(cont’d): Originally conceived as a cable Originally conceived as a cable

replacement technologyreplacement technology Other Other usage modelsusage models began to began to

develop:develop: Personal Area Network (PAN)Personal Area Network (PAN) Ad-hoc networksAd-hoc networks Data/voice access points (LMN)Data/voice access points (LMN) Etc.Etc.

Bluetooth History Bluetooth History (cont’d):(cont’d): 1994 – Ericsson study complete/vision1994 – Ericsson study complete/vision 1995 – Engineering work begins1995 – Engineering work begins 1997 – Intel agrees to collaborate1997 – Intel agrees to collaborate 1998 – Bluetooth SIG (Special Interest Group) formed: 1998 – Bluetooth SIG (Special Interest Group) formed:

Ericsson, Intel, IBM, Nokia and ToshibaEricsson, Intel, IBM, Nokia and Toshiba 1999 – Bluetooth Specification 1.0A1999 – Bluetooth Specification 1.0A

SIG promoter group expanded: SIG promoter group expanded: 3Com, Lucent, 3Com, Lucent, Microsoft & MotorolaMicrosoft & Motorola

2000 – Bluetooth Specification 1.0B, 2000+ adopters2000 – Bluetooth Specification 1.0B, 2000+ adopters 2001 – First retail products released, Specification 1.1 (JSR-2001 – First retail products released, Specification 1.1 (JSR-

82 Java for Bluetooth API based on Spec v1.1)82 Java for Bluetooth API based on Spec v1.1) 2003 – Bluetooth Specification 1.22003 – Bluetooth Specification 1.2 2004 – Bluetooth Specification 2.0(?)2004 – Bluetooth Specification 2.0(?)

Bluetooth Network Bluetooth Network Topology:Topology:

PICONET - PICONET - Collection of devices connected in Collection of devices connected in an ad hoc fashionan ad hoc fashion

One unit acts as master and the others as slaves One unit acts as master and the others as slaves for the lifetime of the piconet for the lifetime of the piconet

Master – device that initiates a data exchangeMaster – device that initiates a data exchange Slave – device that responds to the masterSlave – device that responds to the master

Master determines hopping pattern, slaves Master determines hopping pattern, slaves have to synchronize have to synchronize

Each piconet has one master and up to 7 Each piconet has one master and up to 7 simultaneous slaves simultaneous slaves

Participation in a piconet = synchronization Participation in a piconet = synchronization to hopping sequence to hopping sequence

Cont’d:Cont’d:

Scatternet (intersecting Scatternet (intersecting piconets) piconets) Two or more piconets form a scatternet Two or more piconets form a scatternet Devices can be slave in both or master in one and Devices can be slave in both or master in one and

slaveslave in other in other..

Piconet example:Piconet example:

Scatternet example:Scatternet example:

The Bluetooth Stack:The Bluetooth Stack:

Packet Format:Packet Format:

Access Code: timing synchronization, offset Access Code: timing synchronization, offset compensation, paging and inquiry. compensation, paging and inquiry.

Header: information for packet acknowledgement, Header: information for packet acknowledgement, packet numbering for out-of-order packet packet numbering for out-of-order packet reordering, flow control, slave address and error reordering, flow control, slave address and error check for header. check for header.

Payload: voice field, data field or bothPayload: voice field, data field or both

Bluetooth MAC Protocol:Bluetooth MAC Protocol:

Facilitates communication among Facilitates communication among devices within the piconetdevices within the piconet

Assumes that all devices are Assumes that all devices are synchronized with each other synchronized with each other

Let’s see how it works!Let’s see how it works!

Simulation Design:Simulation Design:

One master and seven slavesOne master and seven slaves Only one is active at a given time Only one is active at a given time

(assumption)(assumption) Assigning addressAssigning address

If (node node address==0)If (node node address==0) MASTERMASTER

else else SLAVESLAVE

• Considers only ACL (data traffic)Considers only ACL (data traffic)• Master polls Master polls

Poll-time is calculatedPoll-time is calculated

Cont’d:Cont’d:• Slave sends Slave sends req.msg (if it has data to req.msg (if it has data to

send)send) Req. time is calculatedReq. time is calculated. Req. msg contains this . Req. msg contains this

slave address and the one to which it wants to slave address and the one to which it wants to send data. It also show packet length.send data. It also show packet length.

If slave has no data to send, slot is wastedIf slave has no data to send, slot is wasted

Master sends, on specifying hops Master sends, on specifying hops (according to demand), sends (according to demand), sends ACK ACK Ack. Time is calculatedAck. Time is calculated

Cont’d:Cont’d: Slave sends its dataSlave sends its data

Transmit time is calculated.Transmit time is calculated. The packet does not reach its destination The packet does not reach its destination

if Pif Ptt <0.5mW <0.5mW Finally overall time and useful time are Finally overall time and useful time are

calculated calculated Calculated time efficiencyCalculated time efficiency Also graph drawn throughput versus loadAlso graph drawn throughput versus load

Performance metrics:Performance metrics:

Throughput Throughput Time efficiency (delay)Time efficiency (delay)

Simulation results(1):Simulation results(1):

Time efficiency = 19.8Time efficiency = 19.8

Too low because of a lot of overhead Too low because of a lot of overhead of polling and setting up connectionof polling and setting up connection

Simulation results(2):Simulation results(2):

Comments:Comments: Too much delay becauseToo much delay because polling (high overhead)polling (high overhead) If slave has no data to send, slot is If slave has no data to send, slot is

wastedwasted Highly centralizedHighly centralized

Bluetooth Future:Bluetooth Future:

Bluetooth was originally intended to Bluetooth was originally intended to be a cable replacement, be a cable replacement,

but, has evolved to become an but, has evolved to become an infrastructure for Personal Area infrastructure for Personal Area Network (PAN)Network (PAN)

2001: 10 million devices produced2001: 10 million devices produced 2003: 70 million!2003: 70 million!

Thank Thank youyou