04/21/23 1

Short-Range Radio Frequency Networking

B. Ramamuthy

04/21/23 2

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.

Bluetooth.com source:

04/21/23 3

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.

04/21/23 4

Figure 3.18 A typical NAT-based home network 83.215.152.95

Ethernet switch

Modem / firewall / router (NAT enabled)

printer

DSL or Cableconnection to ISP192.168.1.xx subnet

PC 1

WiFi base station/access point 192.168.1.10

192.168.1.5

192.168.1.2

192.168.1.1

192.168.1.104 PC 2192.168.1.101

Laptop

192.168.1.105

Game box

192.168.1.106Media hub

TV monitor

Bluetoothadapter

Bluetoothprinter

Camera

04/21/23 5

Figure 3.22IEEE 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]

04/21/23 6

Details

Radio technologyProtocol stackInteroperable profilesHow does the technology work?How is the technology used?Sample APIs to work with bluetooth:javax.bluetooth; javax.obex (for object

exchange)

04/21/23 7

Radio technology

2.5Ghz ISM bandThe 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.

04/21/23 8

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

04/21/23 9

Bluetooth Protocol Stack

Bluetooth Radio

Baseband Link Controller (LC)

Link Manager protocol (LMP)

Host Controller Interface Firmware

Bluetooth Host ControllerFirmware + Hardware

Host controller interface (HCI)

Logical link control & Adaptation Protocol (L2CAP)

RFCOMM (serial port emulation)

OBEX

WAPUDP/TCP

IPPPP

Service discovery protocol (SDP)

Bluetooth HostController Stack(software)

Java API for Bluetooth wireless technology (JSR-082)

Application

04/21/23 10

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.

04/21/23 11

Application activities

java.sun.comBluetooth intro

04/21/23 12

Discovery

04/21/23 13

Bluetooth clients

DiscoveryAgent support discovery of services and devices.

Clients wanting to be notified should implement and register Discovery Listener interface.

04/21/23 14

Service/device discovery

A similar sequence can be assumed for device Discovery.

Services have a UUID

There is LocalDeviceAnd RemoteDevice APIs to control the devices.

04/21/23 15

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

04/21/23 16

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.

Serial Port Profile (SPP)

04/21/23 17

04/21/23 18

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.

04/21/23 19

Profiles

04/21/23 20

How does it work?Bluetooth frame structure

SCO packets (e.g. for voice data) have a 240-bit payload containing 80 bits of data triplicated, filling exactly one timeslot.

bits: 72 18 18 18 0 - 2744

Access code Headercopy 1

Headercopy 2

Headercopy 3

Data for transmission

bits: 3 1 1 1 4 8

Destination Flow Ack Seq Type Header checksum

Address withinPiconet

= ACL, SCO,poll, null

Header

04/21/23 21

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

04/21/23 22

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

04/21/23 23

Uses of Bluetooth

Some are from Accenture:Wiring the wiredLocating lost itemsActivity sensing + auditingEnvironmental controlSimple transactionsMedical applications are unlimited