BluetoothSimulation

Developers:

Eran Cohen

Ran Zavhon

Guide:

Gil Zusman

Project Motivation

BUTThere are still some uncovered problems : • Bluetooth scaternets are not yet fully defined.

• The Bluetooth scheduling algorithm.

• Bluetooth routing protocols.

• Some other problems.

Bluetooth is a world wide standard and is developed by the most influencing companies in the world.

In this project we will concentrate on the scheduling problem

A Little About Bluetooth

Piconet :

A group of 2 – 8 units connected between them, constructing

a Bluetooth basic network .

Scaternet :

A more complex bluetooth network, built out of piconets.

Bluetooth uses a Time Division Duplex scheme :

• Each slot is 625usec long• The master start transmitting only in even slots and slaves

reply only in odd slots.

•Packets can be transmitted in 1,3,5 slots .

Bluetooth Stack

Bluetooth Scheduling Problem

The approximately throughput in the scenario is 75% .

Once a master polls a slave , the next slot is reserved for the slave irrespective of whether the slave has data to send or not .

Project Goal

• Simulate the Bluetooth protocol in a software environment .

• Check the Bluetooth scheduling methods with a numerous

scheduling algorithms :

Round Robin (the method exist on BT devices today).

Exhaustive

Gated

Globally Gated

Other Priorities algorithms

Exhaustive – The master empties the buffer completely

before transferring to the next slave.

Gated – the same as Exhaustive but empties only the packets

that were in the buffer when the master got to the slave.

Globally Gated – Same as Gated but in a predefined bigger

period of time.

Other Priorities algorithms –

Priority scheme algorithm, K-Fairness algorithm and

some more ideas that will come in time .

Choosing the simulation environment

we had some options :

Writing our own simulator.

Getting a commercial simulator.

Ns – An academic simulation package.

We chose NS Network Simulator

NS Advantages :

Has implementation of wide variety of network protocols.

Powerful analysis tools.

Open sourced – written in C++ and OTcl.

Maintainability.

Reliability.

NS – Network Simulator

NS is a software package which can simulate most of the network protocols exist today and those which are in development.

NS Basics

NAM – Network Animator

NS Graphical User Interface

BlueHoc

BlueHoc simulator provides a Bluetooth extension for the Network Simulator – NS.

BlueHoc was developed in IBM research labs and released on the 10.2.2001.

BlueHoc simulates a Bluetooth piconet consisting of a master and 1-7 slaves.

Scatternet and mobility are not implemented yet.

 

The following Bluetooth layers have been simulated by BlueHoc:

Bluetooth radio.

Bluetooth baseband.

Link Manager Protocol (LMP).

Logical Link Control and Adaptation Protocol (L2CAP).

A very degenerate Bluetooth Host.

 

Deficit Round Robin

The scheduling algorithm implemented in BlueHoc.

A scheduling scheme which enforces the Master to poll to every slave on a specified slot (even slots only) , and the next slot is reserved for that slave irrespective of weather it has data to sent or not.

BlueHoc States Simulation

ST = standby , I = inquiry , IS = inquiry scan , IR = inquiry response , P = pagePS = page scan , SR = slave response , MR = master response , C = connection

Next Semester’s Work

-Implementation of scheduling algorithms above

BlueHoc extension for NS.

- Extending the BlueHoc capabilities evolving an

accurate simulation of the Bluetooth network.