Powerline Wireless: The Solution to Wireless Dead Zones

Powerline networking technology may sound pretty fancy and complicated, but it's not. The technology simply extends an Ethernet network via the existing 110-volt wiring of your client's office or home. The only special equipment you'll need to "bridge" over wireless dead spots within any structure are a few inexpensive powerline network adapters, sometimes called powerline bridges. Here's a photo of one:

If you've ever set up any kind of wireless router or access point, you already know the limitations of wireless technology. While equipment manufacturers claim ranges of 150 to 200 feet, in the real world, that's dreaming. Actual performance starts to suffer anywhere from about 80 feet to 150 feet beyond the router antenna. Also, the structural impediments of most buildings reduce ranges pretty quickly.

The powerline approach is an ideal solution. You don't need to get into the walls to install more networking cable. The copper wiring already exists in the building's pre-existing electrical circuits.

Getting Started

You'll need less than an hour to set up the whole deal. It's essentially a two-part process: First, install the powerline adapters. Then, configure the wireless adapter(s).

The powerline adapter installation process takes minutes. To start, all you need is an existing computer with a broadband connection of any sort and a router with one open Ethernet port.

You can buy powerline adapters from all the major networking companies, including Belkin, Linksys, Netgear, D-Link and SMC. For this TechBuilder Recipe, I used SMC product #SMCHP1D-ETH because the hardware has a 10/100 megabit-per-second (Mbps) interface, as opposed to 10 Mbps from the other manufacturers. I also noticed that product reviewers claim the SMC gear performs about 1 Mbps faster than other equipment.

All the manufacturers use the HomePlug 1.0 standard -- that's the wiring standard for 110-volt adapters -- so you can mix them and they still work. You just won't get greater than 10-Mbps throughput with equipment that's not 10/100. And these adapters are also compatible with any standard Wi-Fi gear.

Four quick steps will get your powerline network established:

Run the installation CD on the computer that has the broadband connection and router/hub.
Install the software, then reboot the machine.
While the computer is rebooting, connect the hardware. Plug the powerline adapter's Cat-5 cable into your router or hub. Then plug the powerline adapter into the wall socket. The adapter must go directly into a wall socket; it cannot go into a power strip or UPS (uninterruptible power supply) to work properly.
Plug an additional powerline adapter into a power plug anywhere else in the building or office. Repeat wherever you like. At this point, you don't need to connect a computer or access point to this adapter. Essentially, all you've done is extended the network. It's as if you just pulled Cat-5 cable through the walls.

You can now see the existing powerline adapters on the plugs throughout the premises by using the configuration utility on the PC you have connected to the main router, as shown in this next screenshot:

Now you have points throughout the premises where you can connect computers directly to the network. This is pretty compelling in itself. Anywhere there's a power plug, you can plug in a powerline adapter and then plug a Cat-5 cable -- and the notebook or desktop it's connected to -- right into the adapter. Voila, you're on the network, just as if the wiring were an extension of the regular 10/100 network!

Getting Connected, Wirelessly

Next, we'll connect a wireless access point to the powerline adapter that's hanging off the remote electrical plug. You could just plug a computer in here. But the point is to get a wireless network going. Here's how these access points look:

Be sure to select a location for the wireless access point that is both central and unimpeded by heavy structural features. Ideally, you also will find a position that other devices can access by line-of-sight. Finally, the higher you place the antenna, the better the connectivity.

This process takes three physical steps and eight software steps. First, here's the physical set-up:

Connect the wireless access point's Ethernet cable to the powerline adapter.
Connect the access point's power cable to an electrical outlet. I noticed that my home office (circa 1926) does not like it when I plug both the wireless access point and the powerline adapter into the same two-outlet junction box. So I separated them to two different junction boxes, and now everything works fine. If you're working in an older building, too, give this a try.
Check the LEDs on the front of the access point to make sure the status-indicator lights are shining for power, the wireless LAN, and the physical LAN (which goes through the power lines).

Next, run the installation software:

Run the access point installation CD on the "host" computer -- the one that's connected directly to the broadband connection and the wired router.
The installation program will scan the network for wireless access points and show you a list of available access points. Here's a screenshot of a system seeing an access point:
Select the access point you just set up, then select "disable SSID broadcast." The access point you just set up will most likely be the model number of the device. By disabling the SSID broadcast, you make the network invisible to outsiders and enhance security. The SMC equipment I used has a radio button that indicates "invisible."
Configure the network settings for either DHCP for dynamic IP addresses or assign a static IP address to the device. The next screenshot shows how this looks:
If you're using static IP addresses for the access point and the remote clients, input a static IP address, Subnet Mask, and Gateway Address that are consistent with your network. For more information and detail on the wireless-security process, see an earlier TechBuilder Recipe, Eight Steps Toward Securing A Wireless Network.
Enable Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA). WPA is the latest and greatest. See the aforementioned Eight Steps... Recipe for more information.
Verify the settings, and make note of them. Now you've got a wireless access point hanging off the powerline network. It's broadcasting the network connection, which includes the broadband Internet connection.
Fire up a laptop or desktop with a wireless card or built-in wireless capability, and connect it to the wireless access point with the wireless access point manufacturer's software. You'll be able to see the access point on this client machine. With the right "pass phrase," you'll be able to connect to it privately and securely. The level of encryption will depend upon whether you selected 128-bit or 64-bit encryption back in Step 6.

Note: Although the various flavors of Windows will let you set up wireless networking via the OS, it's better to do so with the software supplied by the device manufacturer. That said, if you want Windows to take care of this task, make sure all updates for WPA or WEP are installed beforehand; otherwise, your client computer will be unable to deal with a WPA or WEP set-up on the access point.

Another note: When setting up the access point, pay attention to an important distinction. In this recipe we set up the wireless device as an "access point" rather than a "wireless bridge." An access point hangs off a wired network. Multiple access points communicate with each other via the hard-wired network they tap into, and they must be wired to the same network. PCs or laptops with wireless cards installed can move around the premises while making seamless "hand-offs" between the access points. This is called roaming -- just like in the cellular telephone world. By contrast, a wireless bridge functions as another wireless outpost in a setting where there's one or multiple other wireless routers or access points. These bridges can communicate with each other wirelessly.

With that note in mind, don't set up a wireless bridge unless you already have a wireless set-up functioning. Remember, we're extending the wired network via the power lines. These power lines are all going back to a main wired router and broadband connection. You can have multiple access points throughout the building. But when they tie into the power plugs, they're headed back to the main router and wired broadband connection.

Now that you're all set up, what kind of performance can you expect to see? I'm seeing 45 to 49 Mbps of throughput on my wireless-G network. The wireless Internet connection is at 3.5 Mbps consistently. That's fine, because I only get 300K to 800K speeds via my DSL modem. So there's room to grow if I want to upgrade to a T1 or cable modem.

The whole process is quick and easy. You'll need about five minutes to set up the powerline adapters, and no more than an hour for the first wireless access point. Once you've got it down, you'll be able to add other access points much more quickly.

This is a great way to extend your customers' wireless networks into former dead zones. The new hardware is a breeze to set up, and the new security features put old wireless-network fears to rest.

PHIL DUNN is a technology journalist and independent communications consultant for high-tech companies.

Discuss this and other Recipes with your fellow system builders in the TechBuilder Recipe Forum.