Cutting all Cables: Phoneline vs. Wireless Networking

Typical Conditions

Although ideal conditions can be useful for examining the fundamentals behind a technology, real applications are necessary to determine the practical performance. The definition of typical conditions is quite arbitrary; however these results should be reproducible by other users with the same hardware.

The conditions surrounding a HomePNA 2.0 network are not usually within a users control. That is to say, they usually cannot decide what type of wiring will be installed in their house, or how it will be routed to avoid external interference. Regardless, most homes have a similar wiring scheme therefore these results should be representative of the majority of users. They were obtained on a HomePNA 2.0 network with both devices connected at remote locations of the house. There were 4 phones connected (on hook) and a 640Kbps DSL channel active during all the tests. It is important to know that DSL and HomePNA offer no interference with one another sice they operate on a different frequency spectrum and therefore, both can be operated simultaneously on a line. Also important for DSL users is to remember that the filters provided to block extra DSL noise from disrupting voice communication will block the HomePNA network traffic at any filtered wall jack. The solution is to remove the filter and install it onto the back of the PNA device, since the majority include a pass-thru phone jack. This could be a bit more troublesome for users with in-wall DSL filters.

The environmental variables affecting wireless networking are much more under the users' control. Many variables, including distance from the transmitter, electronic interference and physical barriers can affect performance. Wireless antennae often must be placed very carefully when the remote station is not receiving a strong signal. Subtle changes such as the movement of metal furniture or the closing of a door or even a persons movement can change the signal strength of a connection. Our tests were conducted with a carefully monitored 20dB Signal to Noise ratio at the remote station, according to Lucent's Link Diagnostic software. This is on the lower end of the signal quality range, but still sufficient that all data is transmitted on an 11Mbps bandwidth.

Under conditions that are more representative of normal usage, the performance gap widens slightly. The wireless network suffers from signal attenuation and interference due to distance, however; the HomePNA network runs over wires and does not degrade significantly over distance.