By Claus Hetting, Wi-Fi NOW CEO & Chairman
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Energy prices are rising and consumers are under pressure to reduce energy consumption – that applies to electronic appliances as well, including home Wi-Fi gateways and mesh systems. But what’s the right strategy to keep energy consumption low without sacrificing whole-home Wi-Fi performance? This month’s Calix Pro Tip digs into this question with reference to a few key Wi-Fi technologies.
There are typically two ways to delivering effective whole-home Wi-Fi coverage: The first – and most effective, says Calix – is to let a single high-power Wi-Fi access point (or home gateway) cover and serve the entire home with Wi-Fi. The second involves the use of several low or mid-power devices (mesh APs) to form a distributed mesh architecture that covers the same area.
But mesh networks are not always the most desirable solution, says Calix. A mesh network requires the deployment of multiple mesh units (APs) and this means that the data stream needs to make several hops to get to the Internet. This creates latency, jitter, and a higher risk of interference. The approach also leads to much higher energy consumption, Calix says.
“Energy consumption when using mesh can double, triple, or even quadruple when compared to using just one high-power Wi-Fi AP. And it gets even worse: In cases where small wall plug-in mesh units are used, a mechanical fan is needed to cool each unit. The fan is one of the largest contributors to high energy consumption, not to mention lower MTBF [Mean Time Between Failure] rates. Why? Because the fan runs continuously—whether the mesh unit is being used or not,” says Shane Eleniak, Executive Vice President of Products at Calix.
Another means of reducing energy consumption is by applying the IEEE 802.3az Energy Efficient Ethernet (EEE) standard. In essence this allows an AP to reduce its power when traffic is low. The power can even be altogether eliminated if the port is down, Calix says.
“An additional effective energy reduction technique is called power shedding. In situations where the power has gone out, a broadband subscriber may have a UPS [Un-interrupted Power Supply] unit to maintain lifeline support. A single Wi-Fi AP with built-in voice ports will then turn off all unnecessary functions automatically, except for lifeline support. This power shedding method allows the UPS to support the lifeline service for up to 24 hours,” Shane Eleniak says.
Last but not least: Standard power Wi-Fi (with an EIRP of 36 dBm) will soon be available in the 6 GHz band – meaning for Wi-Fi 6E operation* – and this will result in better coverage due to an increase in available 160 MHz channels.** “At Calix, all Wi-Fi APs are designed to operate at the highest permissible power levels. As a result our current mesh attached rate is only 7%. With standard power Wi-Fi 6E we expect the percentage of households needing mesh to be even lower,” says Shane Eleniak.
“Designing Wi-Fi systems with the optimal energy efficiency from the beginning not only leads to the lowest energy consumption architecture, but also the best Wi-Fi quality and user experience.”
* High power (EIRP of 36 dBm) will be supported via AFC query
** 5 GHz can only support 160 MHz by either crossing the DFS channels or channel concatenation with UNII 1 and 3 if they are both open, which is very rare