HomePNA chipsets enable smart home entertainment networking
The HomePNA "no new wires" home networking standard has paved the way for significant progress in IPTV with chips that reliably stream data, voice, and video over existing wires. The standard has improved business opportunities for service providers and entertainment options for end users, making the smart home a reality today.
These days, the answer to “What’s new on TV?” is far more than a list of sitcoms, dramas, and reality shows. Interactive bidirectional TV is elevating the viewing experience with offerings like AT&T’s U-verse, an IPTV service featuring video on demand, Voice over IP (VoIP), Total Home DVR, and more. A recent report from ABI Research states that demand for IPTV service will increase by an estimated 32 percent annually over the next six years to nearly 79 million global subscribers by the end of 2014.
For consumers, this means they’re one step closer to living in a smart home – a home in which they can pause a show in one room and continue watching it in another, access the Internet on any TV in their house, or program their DVR from half a world away. For service providers, IPTV makes good business sense, as it has proven to retain landline customers for telcos, reduce churn, increase average revenue per user, and boost broadband purchases.
Connecting the home
To understand home entertainment networking, it is important to recognize that service providers bring ample broadband access to the home via ADSL, VDSL, fiber, satellite, and so on. The main challenge is extending broadband throughout the home from room to room and device to device. Throughput requirements for today’s home networks are 5 to 10 times greater than the unidirectional networks of the past. Current networks require the transmission of not just data, but voice and video as well, and these latter applications require flawless delivery. Viewers don’t tolerate packet loss, which causes frozen, pixilated screens.
Three main methods are available for establishing a high-bandwidth home entertainment network. Ethernet wiring (CAT5) is one option, but laying Ethernet cable throughout the home is time consuming and expensive. Drilling holes in walls for new cables is unsightly. Another approach is going the wireless route, but Wi-Fi transmission has proven unreliable, especially for video streaming. The ideal technique uses existing infrastructure to tackle issues of time, expense, and reliability. Often called a “no new wires” solution, this method streams content-rich data, voice, and video over existing coaxial cables and phone lines throughout the home.
To do the job well, however, this approach must overcome issues of noise and coexistence with DSL and other services. Existing wires are also prone to interference from nearby devices, radio waves, impulse noise, and ground bounce. Attenuation poses yet another challenge to delivering data, voice, and video consistently throughout the home. A technology that uses existing wires must be robust enough to accommodate these factors, which vary greatly from house to house.
No new wires
HomePNA 3.1 has emerged as the industry standard that successfully meets these technological challenges while offering service providers a way to reduce deployment costs and more quickly profit from triple-play broadband service delivery.
The International Telecommunication Union (ITU) adopted the first no new wires home networking standard in 2001. HomePNA 3.1 is the ITU’s latest standard (G.9954). It is supported by the HomePNA Alliance, a consortium of leading technology companies working together for an existing wire home networking standard. While the HomePNA Alliance is not a standards body like the ITU, it contributes to standards by developing protocol specifications for networking over existing wires. The group also determines testing standards for products to be HomePNA certified.
Today, four out of the five largest IPTV-deploying telcos in North America have selected HomePNA and are installing it at a rate of 120,000 homes per month. CopperGate Communications has shipped nearly 10 million HomePNA chips (see Figure 1). These chips are embedded in a full ecosystem of devices, including intelligent network interface devices, residential gateways, set-top boxes, bridges, optical network terminals, testing equipment, and masters and endpoints for multi-dwelling unit solutions. Service providers are installing these devices in homes to deliver triple play and other IP services enabled by HomePNA.
This no new wires approach cuts the amount of time installers spend in homes by up to 50 percent, which means they can significantly reduce their operational expenses and offer quality services to cost-conscious consumers.
PHY and MAC
On the Physical (PHY) layer, HomePNA uses a very robust modulation scheme that supports multiple PHY rates of up to 320 Mbps. This affords high flexibility and granularity in various line conditions.
The HomePNA standard uses burst (or frame) transmission, which is typical in the industry. To increase robustness in noisy and constantly changing line conditions (a situation particularly true of phone lines), the HomePNA receiver readapts per frame. It has no memory; instead, it acquires channel characteristics on each individual frame using a preamble attached to every frame. This preamble is used for channel estimation, automatic gain control adjustment, clock frequency offset estimation, and more. Using per-frame acquisition enables the receiver to quickly adapt to dynamic channel characteristics.
On a multinode HomePNA network, transmission can occur at different rates between different nodes. If the line between two particular nodes is noisy, the rate will be reduced to maintain robustness. This flexibility is achieved by an advanced rate adaptation technique, which sets an optimal line rate between any two nodes. In other words, it sets the highest line rate that channel conditions allow while still meeting a certain target error rate. Each pair of transmitters and receivers automatically adjusts to the optimal line rate. Adaptation is based on a “negotiation” between the receiver and transmitter.
The Media Access Control (MAC) layer of HomePNA chips also plays an important role in overcoming noise and maximizing robustness. The MAC layer uses a protocol called Limited Automatic Repeat request (LARQ). Mainly used for phone lines, LARQ retransmits frames received incorrectly by the receiver. This technique is useful for environments with high impulse noise, which is known to cause frequent frame damage.
The MAC layer is very efficient, enabling optimal usage of the available PHY rate. Designed to maintain high efficiency and low latency, the MAC layer guarantees a significant amount of bandwidth for data, voice, and video delivery.
These and other technological features enable HomePNA chips to deliver robust home entertainment networking over existing wires (see Figure 2).
Existing wires extend broadband
The answer to “What’s new on TV?” is more exciting than any new season lineup. IPTV has brought about game-changing opportunities that improve business for service providers and entertainment options for end users. The HomePNA standard has paved the way for this progress with chips that reliably stream data, voice, and video over existing wires. There is indeed a smart path to the smart home; it has been in your home all along.
 ABI Research, “At 32%, Telco TV Tops Pay-TV Platform Growth,” January 14, 2009, www.abiresearch.com/press/1346- At+32%25,+Telco+TV+Tops+Pay- TV+Platform+Growth
Eran Gureshnik is the product line manager of HomePNA products at CopperGate Communications, based in Tel Aviv, Israel, with U.S. headquarters in Newark, California. Having previously worked for Marvell, Intel, and DSPC, he is an expert in communication semiconductors with experience in design engineering, chip and platform architecture, platform and product management, and technical customer support. Eran received his bachelor’s and master’s degrees from the Technion – Israel Institute of Technology.