Bluetooth Hardware CS215Basic ArchitectureEmbedded StackEmbedded StackStackApplicationSlide 7PowerPoint PresentationClock for measurementsBluetooth Hyper termDelay MeasurementsSome ResultsFuture WorkBluetooth Hardware CS215Rohit Kapoor Prabhakar PundirBasic ArchitectureHyper termNo clock supported in stack currentlySerial portRadio linkEmbedded StackRADIOBASEBANDLINK MANAGERHCI DriverL2CAPRFCOMM SDPEmbedded Stacklm – Link Manager. legs – Bluetooth Stack. This is used by the application to access functionality.core – Core functionality for hardware; not actually part of Bluetooth.driver – Some default drivers, UART, USB etc.Stacklegs – contains RFCOMM, SDP, L2CAP, HCI Driver.Other things –ARM SDT 2.51 – Integrated environment which creates binary.genLoadModule – creates an executable which runs from flash.winIrmaLoad – flashes the board.ApplicationSimple Client-Server one-way chat.Client on Master, Server on Slave.Makes use of legs Stack. Order of operations – Configure UART, Starts SDP, Starts RFCOMM, INQUIRY and then CONNECTION.Once connection is established, Client sends a specified number of pkts to server each time Hyper-Term sends a signal.ApplicationApplication may be used to –Measure maximum distance at which connection is “up” in various environments.Measure end-to-end delay for no. of packets at different distances. This gives estimate of PER since increase in delay is due to reTXs.Estimate of PER requires a large no. of measurements.Computations (for measurements)Host stackCompletely embedded and independentHyper-termFlashed stack and applicationbluetoothClock for measurementsHyper termNo clock supported in stack currentlyUse the system clock through the host systemBluetooth Hyper termProblem with Hyper term: not programmable.Bluetooth Hyper term: Searches the system for serial ports and provides a visual interface for handling each port at various speeds.Written in Java and is therefore system independent.Can be custom programmed for various applications that the embedded stack or the ARM processor may not support. (For the purpose of testing)Can also be used to monitor applications running on the bluetooth kit as required.Delay MeasurementsCompute time on one machine just before sending packet through the hyper term.Compute time on the receiver after receiving.Use the difference as a measure for relative delay in transmission.Repeat experiment for different distances, different obstacles and interference conditions.Some ResultsRange –Open environment and no interference – 50-60m .Indoors – Connection goes down behind an obstacle at some distance.In the corridor – Range throughout corridor, but a turn caused connection to go down.Future WorkGet PER for various packet formats.Get TCP running.See interference with WLAN and other BT kits/cards.Try implementing some Scatternet algorithms on top of the BT