Networking%20Bluetooth%20or%20Wireless%20LAN

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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
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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.
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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
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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
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Bluetooth protocol stack
Applications
OBEX
AT commands
WA P
TCS
SDP
RFCOMM
L2CAP
Host Controller Interface
Link Manager
BasebandLink controller
Radio
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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
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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)
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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
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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).
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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.
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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.
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• 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

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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//develope
r.axis.com/products/devboard_bt/index.html