ISM Bands and Indy Cars

Like cars, WiFi technology is getting better and faster over time. Unlike cars, WiFi doesn’t have a big race every year that draws hundreds of thousands of viewers. Nonetheless, the advances in WiFi are both impressive and important for professionals in virtually any and every technology field to understand. So, with the Indy 500 this weekend, we thought we’d take this opportunity to explain WiFi bands using an analogy we can all get behind: cars.

900MHz – Two Lane Country Road

This long, meandering road can get you from one end of the state to the other.  Even though there are not too many other cars on the road, there are only a few lanes and no one seems in any great hurry to get where they’re going.

900MHz WiFi provides the longest range – theoretically up to a few miles in open air with a good antenna.  However, it accommodates the lowest data rate.  It is commonly used to communicate small amounts of information between outdoor equipment and an access point in agricultural applications.

2.4GHz – The Highway Everyone Uses

Even though there are many more lanes available on this road than the aforementioned country road and the posted speed limit is much higher, there is so much congestion during peak hours that no vehicle is even approaching the speed limit anyway. This is the most popular way to get from one end of the metro area to the other and everyone knows about it.

2.4GHz is the ISM band that bears the burden of popularity.  It is by far the most common carrier frequency for wireless connectivity, especially in the home and for offices, and has become a congested space with high interference. The range is much smaller than that of the 900MHz band, but theoretical data rates are much higher. High utilization of the space means you are likely sharing the maximum data rate with nearby devices, but if you manage to find a channel (lane, in the road analogy) that is moving well, you can rely on a decent data rate through at least a few walls or other obstacles.

5GHz – The Toll Road on a No-Toll Day

Although there isn’t a fee associated with using 5GHz as a carrier frequency, this frequency really feels like a blissfully empty toll road compared to the busy 2.4GHz highway.  This road has many, many more lanes than the main highway, a significantly higher speed limit, and fewer cars to boot.  Thus, the posted speed limit is often achievable by the vehicles that choose this road.  Because there are so many more lanes in each direction, this road is much safer for vehicles with large or wide loads.  Sadly, this toll road only cuts around the main area of the city and travelers must rejoin the main highway if they want to go beyond this relatively short stretch of road.

The wide-open road of WiFi – the 5GHz space – has nearly four times the available channels when compared to the 2.4GHz space, and the 802.11ac protocol allows WiFi devices to claim multiple channels to transmit large amounts of data.  So, bring on the double-wide (movie) trailer! Sadly, the higher carrier frequency does not overcome attenuation as well and has a maximum range of only about 2-3m in a traditional residential or office space. This short range can be used as an advantage in a high-density situation, such as many neighboring conference rooms with their own WiFi networks or a building of efficiency apartments.  If your use case can tolerate the shorter range and all your devices have a 5GHz capable antenna, the 5GHz channel really lets you feel the wind in your hair.

60Hz – The Indy 500 Track

The Indy 500 track is no ordinary road. You’re only allowed on if you know what you’re doing.  It is yet unexplored by the general public and requires special vehicles capable of reaching speeds unheard-of on even the fastest public roads.  This track has a very specific size and shape that lets traffic move as quickly as possible in a well-defined loop, but does not permit vehicles to leave the area.

The WiFi version, the 60GHz ISM band, is currently only used in specialized applications, the most common being the wireless transmission of HD video to a display in the same room.  This high carrier frequency cannot penetrate walls (or even humans) and the technology relies on advanced beam-forming techniques to redirect traffic around obstacles.  While the range is tiny and is only practical as an in-room solution, the theoretical throughput approaches 100Gbps across channels 8GHz wide. Yes, GHz. If the entire channel is dedicated to your application and fully utilized, this could let you simultaneously stream hundreds of 4k video feeds or thousands of 1080p videos. Technologies that use this band tend to focus on delivering very high-quality wireless videos one or two at a time and using the additional bandwidth to build in redundancies to account for possible data loss from in-room obstacles. There is no formalized standard for this space yet outside of proprietary technologies, but 802.11ay could be standardized as yearly as 2019.  WiFi radio manufacturers like Qualcomm are already developing tri-band radios that are prepared to transmit on this short-range, high throughput band.

Although not necessarily as thrilling to watch as the Indy 500, the advancements in WiFi technology over the years have been dramatic and pretty exciting when it comes to the new possibilities they will enable. At Mersive, we’re excited about the potential of streaming multiple video sources at perfect quality wirelessly, and are curious to see how these technological advancements will change how we meet and collaborate. For applications like ours and many others, the ability to move mass amounts of data has never been more in demand, and doing so wirelessly has become critical with the popularization of mobile computing. Whether you spend this weekend on a long and windy country road or get a speeding ticket pretending to be Scott Dixon, we hope this article raised your wireless IQ and maybe even makes you appreciate why your WiFi speeds may seem stuck in traffic!

 

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