Is Bluetooth a Viable Alternative to 802.11b?by Wei-Meng Lee
This article is not a point-by-point comparison of Bluetooth versus 802.11b. There are many good places on the Web to get that information, such as this resource page on wallstreetweb.nl.
What I will do here, however, is provide some detail about my recent experience of using a Bluetooth Access Point for Internet connectivity and consider the notion of using Bluetooth in place of 802.11b wireless networking (in certain situations).
Using the Bluetake Bluetooth Access Point
The test unit that I'm working with is the Bluetake BT300 Bluetooth Access Point (AP), which is Bluetooth 1.1 compliant and supports an operating range of 100 meters (300 feet). The AP comes with two interfaces: RS232 and a 10/100 Base-T Ethernet port. It supports the Bluetooth LAN Access profile and operates at a maximum data rate of 1Mbps.
|Figure 1 -- The Bluetake BT300 Access Point|
To connect the AP to the network, I plugged it in into my network hub and powered it up.
|Figure 2 -- The Bluetake Class 1 (100 meters) USB Bluetooth dongle and a Class 3 (10 meters) Billionton USB Bluetooth adapter|
I used two USB Bluetooth adapters: one from Bluetake (the BT007 Bluetooth USB Dongle) and one from Billionton (the USBBT02-X Bluetooth USB adapter). The BT007 Bluetooth adapter is a Class 1 device, which means that it has a wider operating radius of 100 meters (300 feet). The Billionton adapter, however, is a class 3 device, operating at a range of 10 meters (30 feet). Both can transmit at a maximum rate of 1Mbps.
After installing the Bluetooth software provided by the USB Bluetooth adapters, I am able to use it to perform a search for the AP. If the AP is working correctly, you should see the AP, as shown in the diagram below:
|Figure 3 -- Searching the Bluetooth Access Point|
Once the AP is found, right-click on it and select Connect LAN Access using PPP.
|Figure 4 -- Using PPP to connect to the Access Point|
The computer will then attempt to establish a PPP connection with the AP.
|Figure 5 -- Establishing a connection to the Access Point|
When prompted for User name and password, simply leave it empty and click Connect.
|Figure 6 -- No authentication needed|
That's it. Your computer is now connected to the AP. You can view the status of the PPP connection by right-clicking on the LAN Access using PPP icon (which appears after the successful PPP connection) and selecting Status.
|Figure 7 -- Check the signal strength in the Status window|
Here you can see the signal strength of the connection. If you were sitting right next to the AP, you would obviously get a good signal, but if you are separated from your AP by walls, you probably get a weak signal.
|Figure 8 -- Signal strength is dependent on how far you are away from the AP|
I realized that the default maximum speed is set to 115200 bps, which does not do justice to Bluetooth, as it is capable of a much higher data rate. So you probably need to set it to a higher number, which is 921600 bps for my case.
|Figure 9 -- Setting the connection speed to the highest you can find|
The AP by default comes with a fixed IP address of 126.96.36.199, and you can configure it using your Web browser. You can set the AP to use DHCP as well as set a passkey (PIN code) for authenticated access. Remember to set the Security level to Level 3 if you want to enable this feature. Be sure to disable your proxy server access in your Web browser before you configure the AP.
|Figure 10 -- Enabling passkey access|
With that set, the next time someone tried to connect to the AP, they will be prompted with the passkey request.
|Figure 11 -- Prompting for a passkey|
With my AP in place, I went ahead to test the connection using my two USB Bluetooth adapters. Performances were comparable except that the Class 1 Bluetake Bluetooth adapter is able to operate at a longer distance. I was able to surf the Web comfortably, without any noticeable difference. One thing I gathered is that Bluetooth works best if there are a lot of free spaces for the radio wave to reach you. I tried locating the AP in a closed room (with concrete walls) and tried accessing the network two rooms apart, and the signal drops to a rather weak level. I did, however, still maintain the connection, albeit a slow one. With Bluetooth, you can connect up to seven devices to the AP, a number that should be sufficient for most home use.
There have been many debates as to which is the ultimate wireless technology that will prevail, and I fully subscribe to the suggestion that Bluetooth is a wire replacement technology, whereas 802.11b is more suitable for network connectivity. However, in certain environments, Bluetooth can be an attractive option for setting up a network.
Most cable modems in the home operate at a speed of 256 or 512 bps. While your 802.11b operates at an 11Mbps speed, it is nevertheless capped by the speed of the cable modem. Add to that, network latency and server delays effectively reduce the actual bandwidth that you get from your cable modem. So, even if you have a fast connection from your computer, you are not fully realizing the benefits from it.
This is where Bluetooth is attractive. The theoretical speed of 1mbps (lower in practice) is still significantly higher than the speed of your cable modem. In terms of cost, the price of Bluetooth adapters and AP are dropping. You can get a Bluetooth AP for around $100 and an adapter for $50.
For coverage, while Class 3 Bluetooth devices have significantly lower operating radius than 802.11b, Class 1 devices with wider operating range are actually suitable for the home environment.
One final word about performance. If you are operating an 802.11b network together with Bluetooth, Bluetooth performance will take a hit. Since they both operate in the 2.4Ghz spectrum, collision of packets will cause Bluetooth devices to resend. Hey, if your mum is operating her microwave in the kitchen, that is also going to interfere with your wireless network. As I was testing in an environment where 802.11b is prevalent, I was not able to do an accurate test of the comparative transmission rate. But hey, I was able to watch without problems the latest version of The .NET Show using my Bluetooth connection.
|Figure 12 -- Watching the 300K stream version of The .NET Show|
I know the topic of Bluetooth versus 802.11b is a fiercely debated one. And I'm bracing myself for some interesting feedback. For me, Bluetooth technology works fine at home. It's also a useful tool to use in the classroom, where I can provide network access (though my network-connected, Bluetooth-enabled notebook) to students equipped with Bluetooth-enabled devices (such as PDAs). Tell me where you have successfully used Bluetooth.