Study and implementation of the Bluetooth protocol stack as a distributed simulation

Abstract

Bluetooth is a new wireless technology standard developed by a consortium of telecommunication and software companies aimed at standardizing short range wireless communication the world over. This project aims to provide a flexible protocol stack, implementing the rules of communication and data transfer in the standard, which can be easily integrated into any Bluetooth enabled device that needs to make use of the unique features and services offered by Bluetooth. This project deals with the design of the protocol layers that comprise the Bluetooth communication stack. Our project focuses on the design and testing of Bluetooth specific layers, namely the L2CAP, Baseband, Service Discovery Protocol layers as well as the RFCOMM layer used for serial port emulation. A basic description of the functionality of each layer and their role in Bluetooth based data transmission is as follows:- Bluetooth Baseband: The Baseband is the physical layer of the Bluetooth, managing physical channels and links apart from other services like error correction, data whitening, hop selection and Bluetooth security. It lies on top of the Bluetooth radio layer in the bluetooth stack. The baseband protocol is implemented as a Link Controller , which works with the link manager for carrying out link level routines like link connection and power control. The baseband also manages asynchronous and synchronous links, handles packets and does paging and inquiry to access and inquire Bluetooth devices in the area. Logical Link Control and Adaptation Protocol (L2CAP): L2CAP packets carry payloads which are carried to the upper layer protocols. L2CAP is layered over the Baseband Protocol and resides in the data link layer.L2CAP provides connection-oriented and connectionless data services to upper layer protocols with protocol multiplexing capability, segmentation and reassembly operation, and group abstractions. L2CAP permits higher level protocols and applications to transmit and receive requirements for L2CAP include protocol multiplexing, segmentation and reassembly (SAR), and group management. L2CAP lies above the Baseband Protocol and interfaces with other communication protocols such as the Bluetooth Service Discovery Protocol (SDP), RFCOMM , and Telephony. Service Discovery Protocol (SDP): Using SDP, device information, services allowed and characteristics of the services are queried between Bluetooth enabled devices. The service discovery protocol (SDP) provides a means for applications to discover which services are available and to determine the characteristics of those available services. RFCOMM RFCOMM is a simple transport protocol, which provides emulation of RS232 serial ports over the L2CAP protocol.The protocol is based on the ETSI standard TS 07.10. Only a subset of the TS 07.10 standard is used and an RFCOMM - specific extension is added.