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Powerline versus WiFi - the pros and cons

Comparing two wireless solutions and examining their relative merits in a home networking environment.

Most of us today have a wireless network in our homes to enable us to enjoy unfettered access to the internet and share data between PCs and networked peripherals like printers. More recently the trend towards connecting into home entertainment devices using ethernet ports to connect to TVs, Blu-ray players, and gaming devices has become increasingly common place. Kaspersky Labs estimates that the current number of UK homes with a wireless LAN installed is around 57 per cent. Ofcom estimates that 1.5 million households (out of a total of approximately 22 million households) have deployed PowerLine Technology to connect them up. But how do the two approaches compare and what are the relative pros and cons? This article aims to provide a perspective on both, as well as discuss some current concerns relating to Powerline prompted by a recently released BBC white paper and examine what impact they are likely to have on future growth of powerline and home networking in general.

Firstly, just to be clear we'll start with some definitions of the two technologies, beginning with Powerline. According to Wikipedia, Power line communications are systems for carrying data on a conductor also used for electric power transmission. Consumers can buy powerline adapter sets at most electronics retailers and use those to establish a wired connection using the existing electrical wiring in the home. The powerline adapters plug into a wall outlet and then are connected via CAT5 cabling to the home's router. Additional adapter(s) can be plugged in at any other outlet to give instant networking and Internet access to an Ethernet-equipped Blu-ray player, a game console (PS3, Xbox 360, etc.) a laptop or an Internet TV (also called OTT for Over-the-Top video) box that can access and stream video content to the TV.

The most established and widely deployed powerline networking standard for these powerline adapter products is from the HomePlug Powerline Alliance. HomePlug AV was adopted by the IEEE P1901 group as a baseline technology for their standard, published 30 December 2010. The company estimates that over 45 million of their devices have been deployed worldwide. Other companies and organisations use different specifications for power line home networking and these include the Universal Powerline Association, the HD-PLC Alliance and the ITU-T's specification.

Wi-Fi on the other hand connects to an IP Gateway offering 802.11n high-speed wireless solutions that can provide ultra reliability, predictable bandwidth and unprecedented high speed performance for real-time data, video and audio distribution in the home. The main challenge associated with Wi-Fi has been overcoming the issues of interference and being able to adequately permeate through brick walls to deliver a latency and jitter- free, secure signal whilst also making the solutions easy enough to install and administer to be handled by the consumer. AirTies provide a range of wireless home networking products including IP Gateways, media servers and set-top boxes and have patent pending technology that overcomes the traditional issues of interference, latency using a mesh networking approach to ensure secure delivery of video and data traffic (including HD and 3D video) around the entire house at the press of a button.

Powerline and wireless are currently being used equally by operators around the globe. Some countries like France have developed a particular predilection for powerline but it only works 75 per cent of the time. The two key issues associated with it are firstly one relating to the cabling configuration and the second to interference. In order for powerline to work, the devices it is connecting to need to be physically located on the same circuit. This however is not always the case, as many houses have separate circuits for the 3 different phases of electric power that comes to the home to reduce the load on each wire. Such a design is particularly common in Germany and in new builds where the need for increased power necessitates the use of multiple circuits. In these circumstances powerline technology will not work throughout the whole home.

The second problem is one of interference caused by leakage of RF signals. As the number of powerline devices in the same area increases and powerline technology is being used by multiple households; particularly in a multi-tenanted environment like a flat; the signals are being shared amongst multiple users and the risk of interference and degradation occurs, leading to a reduction in throughput of data as the signals are all sharing the same frequency. Other electrical equipment also injects noise into the electrical wires resulting in degredation in the performance of PLAs nearby.

However, on the positive side powerline technology is now in its third or fourth generation and the maximum data rate, which was previously around 200 Mbps has now increased to 500 Mps and powerline is a well established technology with a range of suppliers. Yet, whilst its use may be suitable in most cases for sharing data its use for HD video sharing is still not proven and prone to interference.

The most recent controversy around powerline relates to the interference that it causes for other electrical equipment as powerline signals radiate into the air so have a tendency to interfere with other electrical devices like short wave and medium wave radios that share the same frequency which can interfere with the functioning of these devices. What's more, the faster models have also been shown to interfere with DAB and FM radio and interference levels have also been shown to exceed current EU standards. If a number of households are using powerline devices in the same area the leaked signals can build up. Ofcom has received some complaints - mainly from radio buffs - about this issue of interference which has largely been ignored due to the small number of complaints. More recently however the BBC published a white paper causing the matter to be discussed in parliament.

However one key area where wireless consistently wins out over powerline is in incorporating into the home network mobile devices like the Apple iPad and other tablet devices which have no ethernet connection. As video is also increasingly being used by these devices which have no fixed location, wireless is undoubtedly the best option.

In conclusion, how do the two solutions stack up against each other? My belief is that they are largely complementary solutions. Wireless isn't constrained by the existence or quality of the existing cabling infrastructure. It offers higher speeds, greater predictability and quality and the option of moving devices at will. However, as demand for more and more bandwidth in the home heats up, adding powerline into a wireless environment can increase bandwidth, adding an extra bandwidth that can be obtained through powerline on top of the bandwidth supplied by wireless networking devices. So whilst the answer is not clear cut - and at some stage the issue of interference will need to be addressed by the powerline standards body - I believe that there is a rosy future ahead for both technologies to co-exist in parallel in the home environment. What's more, the home networking revolution has only just begun and the ease and efficiency with which all devices in the home will interact and seamlessly share video and data is set to escalate exponentially in the near future.

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