Short-Range Radio Frequency Networking B. Ramamuthy 4/6/2019

Purpose Study personal area network PAN and related standard in bluetooth Based on java.sun.com Bluetooth API overview, design and development. Other sources: Colouris text and palo wireless bluetooth resource center. 4/6/2019

Introduction Bluetooth is protocol for short range, frequency hopping radio link between devices. Devices such as phones, PDAs, medical devices that are bluetooth-enabled. Based on Industrial, Scientific and Medical (ISM) frequency band. Unlicensed and globally available. Originally from Ericsson; bluetooth named after a Nordic king instrumental in integration of Scandinavian countries. 4/6/2019

Figure 3.18 A typical NAT-based home network 4/6/2019

Figure 3.22 IEEE 802 network standards IEEE No. Name Title Reference 802.3 Ethernet CSMA/CD Networks (Ethernet) [IEEE 1985a] 802.4 Token Bus Networks [IEEE 1985b] 802.5 Token Ring Networks [IEEE 1985c] 802.6 Metropolitan Area Networks [IEEE 1994] 802.11 WiFi Wireless Local Area Networks [IEEE 1999] 802.15.1 Bluetooth Wireless Personal Area Networks [IEEE 2002] 802.15.4 ZigBee Wireless Sensor Networks [IEEE 2003] 802.16 WiMAX Wireless Metropolitan Area Networks [IEEE 2004a] 4/6/2019

Details Radio technology Protocol stack Interoperable profiles How does the technology work? How is the technology used? Sample APIs to work with bluetooth: javax.bluetooth; javax.obex (for object exchange) 4/6/2019

Radio technology 2.5Ghz ISM band The bluetooth devices in a proximity form a piconet comprising a master and upto 7 devices. Piconets can connect, the master in a piconet can provide a bridge. Global and unlicensed. 4/6/2019

Protocol Stack Protocol stack provides a number of higher level APIs for service discovery and serial IO simulation, lower-level protocols for packet segmentation and reassembly, protocol multiplexing and QoS 4/6/2019

Bluetooth Protocol Stack Application Java API for Bluetooth wireless technology (JSR-082) WAP UDP/TCP IP PPP OBEX Bluetooth Host Controller Stack (software) Service discovery protocol (SDP) RFCOMM (serial port emulation) Logical link control & Adaptation Protocol (L2CAP) Host controller interface (HCI) Host Controller Interface Firmware Link Manager protocol (LMP) Bluetooth Host Controller Firmware + Hardware Baseband Link Controller (LC) Bluetooth Radio 4/6/2019

Typical application Scenarios Bluetooth application can be either server or client Peer-peer exposing both client and server functionality Application need not be in Java However J2ME-based devices can avail of the bluetooth API. Though we discuss Java-based API here, MS Vista has a WS based API for devices. 4/6/2019

Application activities java.sun.com Bluetooth intro 4/6/2019

Discovery 4/6/2019

Bluetooth clients DiscoveryAgent support discovery of services and devices. Clients wanting to be notified should implement and register Discovery Listener interface. 4/6/2019

Service/device discovery A similar sequence can be assumed for device Discovery. Services have a UUID There is LocalDevice And RemoteDevice APIs to control the devices. 4/6/2019

Service discovery (contd.) Once the local device has discovered at least one remote device, it can begin to search for available services – Bluetooth applications it can use to accomplish useful tasks. Because service discovery is much like device discovery, DiscoveryAgent also provides methods to discover services on a Bluetooth server device, and to initiate service-discovery transactions 4/6/2019

Serial Port The RFCOMM protocol, which is layered over the L2CAP protocol, emulates an RS-232 serial connection. The Serial Port Profile (SPP) eases communication between Bluetooth devices by providing a stream-based interface to the RFCOMM protocol. Some capabilities and limitations to note: Two devices can share only one RFCOMM session at a time. Up to 60 logical serial connections can be multiplexed over this session. A single Bluetooth device can have at most 30 active RFCOMM services. A device can support only one client connection to any given service at a time. 4/6/2019

Interoperable Profiles Profiles have been developed to manage cross-platform interoperability among different manufacturer’s products. They describe how implementations of user models have to be accomplished. Lets examine the bluetooth profile as provided by palowireless. 4/6/2019

Profiles 4/6/2019

How does it work? Bluetooth frame structure bits: 72 18 0 - 2744 Access code Header copy 1 Header copy 2 copy 3 Data for transmission bits: 3 1 4 8 Destination Flow Ack Seq Type Header checksum Address within Piconet = ACL, SCO, poll, null Header SCO packets (e.g. for voice data) have a 240-bit payload containing 80 bits of data triplicated, filling exactly one timeslot. 4/6/2019

Server operation Construct a URL that indicates how to connect to the service, and store it in the service record Make the service record available to the client Accept a connection from the client Send and receive data to and from the client The URL placed in the service record may look something like: btspp://102030405060740A1B1C1D1E100:5 4/6/2019

Client operation To set up an RFCOMM connection to a server the client must: Initiate a service discovery to retrieve the service record Construct a connection URL using the service record Open a connection to the server Send and receive data to and from the server 4/6/2019

Uses of Bluetooth Some are from Accenture: Wiring the wired Locating lost items Activity sensing + auditing Environmental control Simple transactions Medical applications are unlimited 4/6/2019