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Networking Bluetooth or Wireless LAN. What are ad hoc wireless networks?. Overview of Bluetooth technology. Bluetooth protocol stack. The Ericsson Bluetooth module. Alternate solutions. Wireless LANs. Conclusions. References. Ad hoc wireless networks.
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NetworkingBluetooth or Wireless LAN What are ad hoc wireless networks? Overview of Bluetooth technology Bluetooth protocol stack The Ericsson Bluetooth module Alternate solutions Wireless LANs Conclusions References
Ad hoc wireless networks Mobile ad hoc networks and smart sensor networks – Embedded Networked Sensors (ENS). Network formed by mobile wireless nodes independent of fixed infrastructure or centralized administration. 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 625s) Two types of links can be established, ACL and SCO ACL: Asynchronous Connection-Less SCO: Synchronous Connection Oriented
Bluetooth protocol stack Applications OBEX AT commands WA P TCS SDP RFCOMM L2CAP Host Controller Interface Link Manager Baseband+Link controller Radio
Reference to the OSI model Application Layer Application Layer Presentation Layer RFCOMM/SDP Session Layer L2CAP Transport Layer HCI Link Manager Network Layer Link Controller Data Link Layer Baseband Physical Layer Radio
Ericsson Bluetooth module Requires a host to control the module USB and UART interface for communication with host Comes with the Bluetooth PC reference stack for Windows Point to point or point to multipoint modules Users need to get acquainted with the API Cost: $150 per module (point to point)
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?). Point to point communication using ad hoc mode or communicate through the access points already installed – infrastructure mode. Ease of programming! Highly available and tested on all major platforms. Less expensive than any Bluetooth solution today (Available for under $100).
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 • expensive ($140) • Troy EtherWind-Plus for embedded device applications. Price N/A. • Iosoft ChipWeb Wireless: Wireless Development kit for the • PIC μC. ($260-$300). • Check TigerDirect.com for wireless adapters. Bluetooth adapter • (Belkin) for $35
References The Bluetooth website http://www.bluetooth.com Bluetooth Revealed by Brent A. Miller, Chatschik Bisdikian Bluetooth: Connect without cables by Jennifer Bray, Charles F. Sturman Application and training toolkits from Ericsson http://www.comtec.teleca.se Axis Developer board for Bluetooth http://developer.axis.com/products/devboard_bt/index.html