Narrowing home network shortlist

The odds are improving for Wi-Fi against three standardised wireline options. By Philip Hunter

Like it or not, IPTV providers will have to confront the home network, or “last 30 metres” sooner rather than later, facing both a threat and an opportunity. The threat is that Quality of Service (QoS) may be inadequate for TV over some home network technologies, creating logistical headaches and also negative publicity for IPTV, even if the operator is not directly to blame. The associated opportunity is that by getting involved in the home network, operators can offer IPTV services that exploit synergy with voice and the Internet. There are multiple products and approaches, varying not only between countries and regions but also between individual households. There is also some confusion over the role of middleware in transmitting content around a home network. Orca Interactive established its Interactive Alliance in June 2006 to promote application interoperability for IPTV with emphasis on the home network

Physical layer

The biggest issue in deciding between the available options has been with the physical layer. The fact that few households would opt for new cabling has narrowed the list of options to MoCA (Multimedia over Coaxial Alliance), HomePNA (Home Phoneline Networking Alliance), HomePlug A and, naturally, Wi-Fi (IEEE 802.11). All have pros and cons and highlight the regional variations. Coax is absent in many European countries but is installed in 80% of US homes; another advantage being robustness and an ability to carry 270 Mbps. Verizon Communications chose MoCA for its FiOS home networking service. HomePNA has the advantage of supporting both coax and twisted pair phone wiring, giving it greater appeal worldwide. The November 2006 release of HomePNA 3.1 boosted speeds from 128 Mbps to 320 Mbps, prompting AT&T to switch from MoCA to HomePNA 3.1 for its Project Lightspeed and U-Verse IPTV deployments. The dark horse of home networking has been HomePlug AV, which has a reach advantage since it works over electrical wiring. With technical teething troubles now resolved, it transmits reliably at 100 Mbps and theoretically attains 200 Mbps. Corinex Ethernet adapters have been selected by Telefonica. However, the fate of all three cabling options lies largely in the hands of Wi-Fi. The key lies not in raw bandwidth, which is more than adequate for multiple
HDTV streams in emerging versions, but in whether it can evolve to operate reliably with sufficient QoS, given that many older European buildings have thick walls and use metal, which can create black holes.

Wi-Fi optimism

Yet there is optimism within the Wi-Fi camp too, in that two emerging standards, IEEE 802.11s and 802.11n, will mitigate reliability and QoS concerns to make wireless the natural choice, and better able to meet the needs of laptop and mobile users to access the home network. Technical problems have held up 802.11n, which is not likely to be ratified until 2008, although it promises to deliver robust video by using MIMO (multiple-in, multipleout). MIMO is also described as spatial multiplexing because it splits data into multiple streams that take different paths through the physical space by being projected at varying angles, thus reducing the chance of drop-outs and increasing capacity to beyond 300 Mbps. IEEE 802.11s complements this by supporting a mesh architecture comprising multiple radio access points. This should enforce interoperability between different home routers and create the potential for delivery of IPTV or external Wi-Fi networks that interface with the home network via a portal, as well as increasing reliability by creating alternate paths between the different access points. 802.11s creates resiliency and capacity by having multiple points, while IEEE 802.11n, via spatial multiplexing, achieves this by taking multiple paths between just two points.

Ruckus Wireless

Technology from Ruckus Wireless may make the wait unnecessary. The company’s MediaFlex NG supports multiple virtual access points over existing Wi-Fi without the new standards, has been deployed by PCCW and is supported by Orca, Entone, ADB and several other set-top box makers. It remains to be seen how this will fare against the three wireline options during 2008 and it is possible that one will miss the cut at some stage. The odds are improving for Wi-Fi.