Modeling & Simulation of Bluetooth MAC protocol COE543 Term Project Spring 2003 Submitted by: H.M.Asif (ID# )

Outlines: Bluetooth overview Bluetooth overview The Bluetooth Stack The Bluetooth Stack Bluetooth MAC protocol Bluetooth MAC protocol Simulation design and Assumption Simulation design and Assumption Results Results Future work Future work Conclusion Conclusion

Bluetooth overview: What is Bluetooth? What is Bluetooth? Why Bluetooth? Why Bluetooth? Bluetooth History Bluetooth History Bluetooth Network Topology Bluetooth Network Topology

What is Bluetooth? Cable replacement technology primarily Cable replacement technology primarily Bluetooth wireless technology is an open specification for a low-cost, low-power, short-range radio technology for ad-hoc wireless communication of voice and data anywhere in the world. Bluetooth wireless technology is an open specification for a low-cost, low-power, short-range radio technology for ad-hoc wireless communication of voice and data anywhere in the world.

Cont’d: Bluetooth uses a frequency-hopping scheme in the unlicensed Industrial Scientific-Medical (ISM) band at 2.4 GHz. Bluetooth uses a frequency-hopping scheme in the unlicensed Industrial Scientific-Medical (ISM) band at 2.4 GHz. The major goal with the Bluetooth wireless technology is to allow relatively cheap electronic devices to communicate directly in an ad-hoc fashion, Moreover, the Bluetooth equipped devices can also form networks– such a network of personal devices is often referred to as a personal area network (PAN). The major goal with the Bluetooth wireless technology is to allow relatively cheap electronic devices to communicate directly in an ad-hoc fashion, Moreover, the Bluetooth equipped devices can also form networks– such a network of personal devices is often referred to as a personal area network (PAN).

Why Bluetooth?  Cable replacement between devices.  Open Specification  Low power consumption  Devices can be connected to multiple devices at the same time.  Operate in Un-licensed band (2.4GHz ISM)

Bluetooth Technical Features: 2.4 GHz ISM Open Band 2.4 GHz ISM Open Band Globally free available frequency Globally free available frequency 79 channels ( MHz ISM band) 79 channels ( MHz ISM band) Frequency Hopping & Time Division Duplex (1600 hops/second typically) Frequency Hopping & Time Division Duplex (1600 hops/second typically) Meter Range 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 Mbps Link 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 data ACL (Asynchronous connectionless link) for data Transmit Power: 0dbm Transmit Power: 0dbm Receiver Sensitivity : -73dbm Receiver Sensitivity : -73dbm Uses Binary GFSK Uses Binary GFSK

Bluetooth History: King Harold Blatand, or Bluetooth, a Viking and King of Denmark , united Denmark & Norway King Harold Blatand, or Bluetooth, a Viking and King of Denmark , united Denmark & Norway 1994 – Ericsson study on a wireless technology to link mobile phones and accessories 1994 – Ericsson study on a wireless technology to link mobile phones and accessories

Bluetooth history (cont’d): Originally conceived as a cable replacement technology Originally conceived as a cable replacement technology Other usage models began to develop: Other usage models began to develop: Personal Area Network (PAN) Personal Area Network (PAN) Ad-hoc networks Ad-hoc networks Data/voice access points (LMN) Data/voice access points (LMN) Etc. Etc.

Bluetooth History (cont’d): 1994 – Ericsson study complete/vision 1994 – Ericsson study complete/vision 1995 – Engineering work begins 1995 – Engineering work begins 1997 – Intel agrees to collaborate 1997 – Intel agrees to collaborate 1998 – Bluetooth SIG (Special Interest Group) formed: Ericsson, Intel, IBM, Nokia and Toshiba 1998 – Bluetooth SIG (Special Interest Group) formed: Ericsson, Intel, IBM, Nokia and Toshiba 1999 – Bluetooth Specification 1.0A 1999 – Bluetooth Specification 1.0A SIG promoter group expanded: 3Com, Lucent, Microsoft & Motorola SIG promoter group expanded: 3Com, Lucent, Microsoft & Motorola 2000 – Bluetooth Specification 1.0B, adopters 2000 – Bluetooth Specification 1.0B, adopters 2001 – First retail products released, Specification 1.1 (JSR-82 Java for Bluetooth API based on Spec v1.1) 2001 – First retail products released, Specification 1.1 (JSR-82 Java for Bluetooth API based on Spec v1.1) 2003 – Bluetooth Specification – Bluetooth Specification – Bluetooth Specification 2.0(?) 2004 – Bluetooth Specification 2.0(?)

Bluetooth Network Topology: PICONET - Collection of devices connected in an ad hoc fashion PICONET - Collection of devices connected in an ad hoc fashion One unit acts as master and the others as slaves for the lifetime of the piconet One unit acts as master and the others as slaves for the lifetime of the piconet Master – device that initiates a data exchange Master – device that initiates a data exchange Slave – device that responds to the master Slave – device that responds to the master Master determines hopping pattern, slaves have to synchronize Master determines hopping pattern, slaves have to synchronize Each piconet has one master and up to 7 simultaneous slaves Each piconet has one master and up to 7 simultaneous slaves Participation in a piconet = synchronization to hopping sequence Participation in a piconet = synchronization to hopping sequence

Cont’d: Scatternet (intersecting piconets) Scatternet (intersecting 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 slave in other. Devices can be slave in both or master in one and slave in other.

Piconet example:

Scatternet example:

The Bluetooth Stack:

Packet Format: Access Code: timing synchronization, offset compensation, paging and inquiry. Access Code: timing synchronization, offset compensation, paging and inquiry. Header: information for packet acknowledgement, packet numbering for out-of-order packet reordering, flow control, slave address and error check for header. Header: information for packet acknowledgement, packet numbering for out-of-order packet reordering, flow control, slave address and error check for header. Payload: voice field, data field or both Payload: voice field, data field or both

Bluetooth MAC Protocol: Facilitates communication among devices within the piconet Facilitates communication among devices within the piconet Assumes that all devices are synchronized with each other Assumes that all devices are synchronized with each other Let’s see how it works! Let’s see how it works!

Simulation Design: One master and seven slaves One master and seven slaves Only one is active at a given time (assumption) Only one is active at a given time (assumption) Assigning address Assigning address  If (node node address==0)  MASTER  else  SLAVE Considers only ACL (data traffic) Considers only ACL (data traffic) Master polls Master polls  Poll-time is calculated

Cont’d: Slave sends req.msg (if it has data to send) Slave sends req.msg (if it has data to send)  Req. time is calculated. Req. msg contains this slave address and the one to which it wants to send data. It also show packet length. If slave has no data to send, slot is wasted If slave has no data to send, slot is wasted Master sends, on specifying hops (according to demand), sends ACK Master sends, on specifying hops (according to demand), sends ACK  Ack. Time is calculated

Cont’d: Slave sends its data Slave sends its data  Transmit time is calculated. The packet does not reach its destination if P t <0.5mW The packet does not reach its destination if P t <0.5mW Finally overall time and useful time are calculated Finally overall time and useful time are calculated Calculated time efficiency Calculated time efficiency Also graph drawn throughput versus load Also graph drawn throughput versus load

Performance metrics: Throughput Throughput Time efficiency (delay) Time efficiency (delay)

Simulation results(1): Time efficiency = 19.8 Too low because of a lot of overhead of polling and setting up connection Too low because of a lot of overhead of polling and setting up connection

Simulation results(2):

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

Bluetooth Future: Bluetooth was originally intended to be a cable replacement, Bluetooth was originally intended to be a cable replacement, but, has evolved to become an infrastructure for Personal Area Network (PAN) but, has evolved to become an infrastructure for Personal Area Network (PAN) 2001: 10 million devices produced 2001: 10 million devices produced 2003: 70 million! 2003: 70 million!

Thank you