Networking Bluetooth or Wireless LAN Overview of Bluetooth technology Bluetooth protocol stack The Ericsson Bluetooth module Alternate solutions Wireless LANs Conclusions References What are ad hoc wireless networks?
Ad hoc wireless networks Network formed by mobile wireless nodes independent of fixed infrastructure or centralized administration. Mobile ad hoc networks and smart sensor networks – Embedded Networked Sensors (ENS). No fixed infrastructure. Autonomous agents. Bandwidth constraints due to wireless links. Dynamic topology. Power constraints.
Overview of Bluetooth technology Short range RF technology for cable replacement Uses FHSS over the 2.4GHz ISM band 79 * channels spaced at 1MHz 1Mbps raw bit rate 3 power classes: 1mW, 2.5mW, 100mW with range from 10m to 100m
Overview of Bluetooth technology Devices assume the role of master or slave Master can communicate with multiple slaves (up to 7 active slaves) Communication channel is TDD (Basic unit of operation is a slot of 625 s) Two types of links can be established, ACL and SCO ACL: Asynchronous Connection-Less SCO: Synchronous Connection Oriented
Bluetooth protocol stack Radio Baseband+Link controller Link Manager Host Controller Interface L2CAP RFCOMM TCS Applications OBEX WA P SDP AT commands
Reference to the OSI model Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer Radio Baseband Link Controller Link Manager HCI L2CAP Application Layer RFCOMM/SDP
Ericsson Bluetooth module USB and UART interface for communication with host Requires a host to control the module Comes with the Bluetooth PC reference stack for Windows Point to point or point to multipoint modules Cost: $150 per module (point to point) Users need to get acquainted with the API
Alternate products PCMCIA cards from IBM, 3COM, Toshiba, ... Axis developer board for Bluetooth 100MIPS 32bit RISC CPU 16MB DRAM with 4MB flash memory Uses the Axis embedded Linux port! SDK for the Linux 2.4 kernel Supports up to 4 Bluetooth clients Cost: $495
Wireless LAN 11Mbps data rate, long range (Requires a host. PDA?). Ease of programming! Less expensive than any Bluetooth solution today (Available for under $100). Point to point communication using ad hoc mode or communicate through the access points already installed – infrastructure mode. Highly available and tested on all major platforms.
Conclusions Bluetooth can be an ideal solution but it is still in the early stages of deployment. High cost and lack of a standard API prevent them from being the first choice. Lack of single chip solutions requires the use of a host. In case a host like a PDA is used, Wireless LAN cards become a better choice.
Discussion Serial-to-PCMCIA bridge or Serial-to-ISA-to-PCMCIA port bridge Easier to build for 802.11b than for Bluetooth. Bluetooth has a requirement for host. RS232 to 802.11b Commercially available bridges can be expensive.
Winncom.com has RS232 (or Ethernet) to 802.11b converter modules. Price N/A.
OTC wireless has a PnP solutions for serial lines at $199.
Also have USB interfaces for $66.
rfdigital.com has a variety of wireless boards (RF) from $30 to $129.
TotalRobots.com has complete wireless solution for using with
RS232 or I2C (about $100)
mrrobot.com has wireless modules of long range (3miles) but
Troy EtherWind-Plus for embedded device applications. Price N/A.
Iosoft ChipWeb Wireless: Wireless Development kit for the
PIC μ C. ($260-$300).
Check TigerDirect.com for wireless adapters. Bluetooth adapter
(Belkin) for $35
References Bluetooth Revealed by Brent A. Miller, Chatschik Bisdikian Bluetooth: Connect without cables by Jennifer Bray, Charles F. Sturman The Bluetooth website http://www.bluetooth.com Axis Developer board for Bluetooth http://developer.axis.com/products/devboard_bt/index.html Application and training toolkits from Ericsson http://www.comtec.teleca.se