Wireless Networking - 25 Apr 2002

Over the past few months, wireless networking has received quite a bit of media coverage, so in my next couple of Mobile & Wireless UPDATE columns, I'll take a closer look at some related technologies. Today, I want to compare Bluetooth and Wi-Fi, the 802.11b wireless standard.

A lot of people ask me whether Wi-Fi or Bluetooth is "better." Although both are 2.4GHz technologies and overlap somewhat, they are more complementary than they are similar. Wi-Fi is an Ethernet replacement technology for wireless network connectivity, whereas Bluetooth is a cable replacement technology for device connectivity. Consequently, each technology solves a different problem and is useful in its own way. I use 802.11b at work and at home for wireless LAN (WLAN) network connectivity, and I use Bluetooth for my mobile phone headset and for synchronizing data on my iPAQ Pocket PC.

Wi-Fi allows transmission of wireless data at speeds as fast as 11Mbps and has a theoretical maximum range of from 300 feet to 800 feet. In my experience, however, Wi-Fi's effective range is less than 100 feet in the average office or home environment, primarily because of the interference caused by walls. Radio frequency (RF) interference also contributes to the limited effective range. Many cordless phones operate at 2.4GHz, and I know several people running Wi-Fi networks who have experienced interference from WLANs and other wireless devices, such as 2.4GHz cordless phones. At home, I use 900MHz cordless phones to avoid such interference.

Bluetooth is a wireless networking standard developed by Ericsson and now controlled by the Bluetooth Special Interest Group (SIG— http://www.bluetooth.com ). Bluetooth has a direct maximum effective range of about 30 feet between devices. At that range, Bluetooth can replace cables—such as those used for headset connectivity, laptop and PDA-to-PDA connections, and access point (AP) connectivity. Bluetooth is more flexible than Wi-Fi, but Bluetooth connection speeds don't exceed 1Mbps.

One huge advantage of Bluetooth is that it consumes only 1 percent of the power that Wi-Fi does, making Bluetooth well suited for use with mobile devices. Bluetooth also experiences fewer interference problems than other 2.4GHz technologies: When interference occurs, Bluetooth simply changes frequencies and retransmits the data. One other key point about Bluetooth is that not only can the devices transmit and receive RF signals, but devices can relay Bluetooth signals to achieve an overall range of about 100 feet. For example, if you want to print to a Bluetooth printer outside the effective range, you can relay the signal through another Bluetooth device, thus effectively increasing the range.

In my next Mobile & Wireless UPDATE column, I'll continue the discussion of Wi-Fi and Bluetooth by examining their connectivity options. See you in a couple of weeks.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.