Problems at Home?

Advances in compression and networking technology are quickly bringing the coveted triple play of digital voice, video and data to consumers over a single broadband connection. But once dropped at the doorstep, how do consumers distribute this digital multimedia content to televisions, personal video recorders and other new multimedia appliances littered throughout the home?

This is one of the biggest obstacles facing the adoption of next-generation multimedia services and a key reason that consumers haven’t embraced services like IPTV more broadly. Providers in Hong Kong and Italy have reported the rejection rate of these new services can be as high as 30 percent due to installation, wiring and networking issues. So what gives?

The broadband connection typically comes into the home through the basement or office – far away from the devices that need it. Meanwhile, the content being delivered over it is now digital – wrapped in IP. That’s a problem for most consumer electronics devices in the living room or bedroom that don’t understand IP.

According to providers, new cable installation to connect the broadband gateway to set-top boxes can take anywhere from four to six hours at a cost of $250 to $500 per subscriber. There are several in-home networking choices available for delivering IP services; however, their reliability is questionable. These options include:

• Coaxial cabling
• In-home power lines
• Category 5 Ethernet wires
• 802.11 Wi-Fi

While each of these choices has strengths and weaknesses, a new variant of Wi-Fi called Smart Wi-Fi, seems to hold the most promise for moving IP multimedia around the home in a predictable manner.

Cabling Costs
Coaxial cabling, a mostly American phenomenon, is not ubiquitous and requires expensive conversion equipment. This makes it cost-prohibitive in most cases.

On average, each home has approximately 2.5 coax connections, each requiring additional cable to be installed. While capable of supporting delay-sensitive applications that require a predictable connection and quality of service – such as IPTV – it’s unlikely we’ll see an affordable coaxial receiver for a laptop or consumer electronics device any time soon, if ever.

Meanwhile, many new homes are built with Category 5 Ethernet cabling throughout. While this solves the basic problem of high-quality multimedia distribution throughout a home, most homes don’t have Ethernet cable in every room and putting it there takes time and money.

The two most promising technologies for delivering IP traffic – powerline and Wi-Fi – also have their issues.

Problems With Power
Every TV or IP-enabled multimedia device requires power. So it makes sense that running IP over power would be both convenient and cost effective. It is, but there’s a catch.

The powerline infrastructure within homes was designed to deliver power, not digital multimedia content. While many new products are boasting theoretical bandwidth speeds of up to 200mbps, tests have shown much lower usable bandwidth rates. This occurs particularly when signals are attenuated by circuit breakers or when there is heavy power consumption by other devices.

In short, pushing data through the power infrastructure introduces a unique set of challenges that powerline as a technology has not presently solved. They include:

• Performance degradation with increasing load: Each additional load will change the impedance profile of the power line.
• Location-dependent performance: Performance deteriorates when the signal crosses circuits, breaker boxes, and surge protectors.
• Interference from household equipment: Anything with a duty cycle (e.g. a dimmer or microwave oven) will interfere with powerline networking. The power line is also sensitive to pulse noise from appliances such as elevators and hair dryers.
• Interference from neighbors: In multi-unit dwellings, interference from neighbors causes interference with the powerline network.
• Inconsistent performance: When connecting a halogen lamp to the same circuit, tests have shown performance decreases of 30 to 60 percent; a surge protector on one end of the link saw drops of 15 to 100 percent; surge protectors on both sides of the link reduced throughput 45 to 100 percent; a hair dryer can reduce throughput by 60 to 100 percent.

So What About Wi-Fi?
Consumers love Wi-Fi. But Wi-Fi has difficulties of its own in delivering multimedia traffic due to range limitations, unpredictable performance, inadequate quality of service and gratuitous handling of multicast traffic.

Wi-Fi signals are transmitted in every direction and dispersed on multiple paths. As a result, they may arrive out of phase, creating a condition called multipath fading. This results in reduced and unpredictable signal strength, temporary dead spots and packet errors.

IPTV usually is delivered from the provider headend as a UDP multicast stream. Today’s Wi-Fi products treat multicast as best-effort traffic, giving it the lowest bandwidth possible. This virtually ensures unwatchable video as there are no mechanisms for ensuring packets arrived or the quality of the signal path.

Enter Smart Wi-Fi
Advances in smart antenna technology and QoS software are solving these problems, making Wi-Fi, for the first time, a reliable and arguably the best option for in-home multimedia distribution.

New smart antenna arrays make use of multiple antennas and expert control software to direct Wi-Fi signals over the best path between two endpoints. This technology continuously tracks the quality of each link. If interference or signal quality degrades, these systems are capable of switching or steering Wi-Fi signals over a better path in milliseconds to maintain consistently high data rates while minimizing packet errors and retransmissions. Wi-Fi signals also are focused in a specific direction, minimizing interference and maximizing range and coverage.

Innovations in sophisticated QoS software automatically classify different types of IP traffic prior to transmission over smart antennas to ensure appropriate bandwidth schedule for different traffic profiles. This guarantees that video, for instance, doesn’t degrade in the presence of data use.

Smart Wi-Fi systems also identify and handle multicast traffic differently. Multicast streams are tuned and prioritized to ensure the same service quality levels equivalent to unicast traffic.

In the end, there won’t be any single perfect solution. But ask any consumer and you quickly find that, if possible, they’d prefer the freedom of wireless coupled with the predictability of wires. Now they can have it.

David Callisch is marketing director at Ruckus Wireless. He can be reached at dcallisch@ruckuswireless.com.

Ruckus Wireless Inc. www.ruckuswireless.com

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