Wi-Fi will be in the Mix for Wireless 'Internet of Things' Supremacy

As system designers look to leverage the capabilities that Internet connectivity can provide, a new phenomenon is emerging called the 'Internet of Things' (IoT). Essentially, IoT aims to not only connect people to their devices, but also each of these devices to one another, enabling them to exchange and act upon information without human intervention.

With Internet Protocol version 4 (IPv4, with room for about 4 billion individual Internet addresses) giving way to IPv6, with 3.4 x1038 or 340,000,000,000,000,000,000,000,000,000,000,000,000—I checked the number of zeroes twice−possible addresses, every device imaginable soon can have its own IP address.

Make no mistake, IoT is an imminent reality. Market researchers suggest that the number of such devices will reach 50 billion by 2020. If you don't believe that number consider that later this year Australian startup LIFX is preparing to ship a Wi-Fi enabled light bulb. The connected light bulb can be controlled by an iPhone or Android smartphone app, according to the company.

At the moment, IoT connectivity relies on a hodgepodge of wireless network standards including Bluetooth LE (Low Energy), Wi-Fi, cellular, ZigBee, RFID, near-field communications (NFC) and/or proprietary solutions such as Z-Wave.

Also at present wireless LAN technology mainly operates through a modem that then transmits signals to desktops, laptops or cell phones and then on to other devices in the network. Using Wi-Fi as a means of communications between, say, a mobile phone and a laptop link is considered to be outside of its purview, so Bluetooth or another technology is used to achieve the connection. In the relatively near future, however, Wi-Fi technology will directly go from the network to terminal devices connected to each other at multi-gigabit speeds, several orders of magnitude faster than Bluetooth, Zigbee or other short range wireless protocol can manage.

Before we get into how this will be accomplished a bit of background is in order. Wi-Fi, or formally IEEE 802.11, traces its development back to 1997 and over subsequent years gradually developed various improved 802.11a / b / g flavors. The 802.11n standard added MIMO (Multi-Input Multi-Output) technology to significantly increase the data rate for faster transfer speeds. This year the newest Wi-Fi iteration, 802.11ac is becoming available offering up to 1.3Gbps of connection speed. Right now 802.11ac product exists mostly in the form of routers, which for backward compatibility also come with 802.11n and hence support all existing Wi-Fi clients. 802.11ac-capable hardware clients are, however, still quite scarce.

802.11ac can be viewed as a continuation of the 802.11n standard, making more use of antenna multiple-input and multiple-output (MIMO) technology ( 802.11n offers four spatial streams, 802.11ac goes to eight). To further increase data throughput 802.11ac also has a wider channel bandwidth−by doubling the channel bandwidth from 20 to 40 MHz, a single transmission can carry twice as much data in the same time. 802.11ac further employs denser modulation; 256 quadrature amplitude modulation (QAM, up from 802.11n's 64QAM) for a 33% speed burst at short range.

Taken together, these features allow 802.11ac chips to transfer data three times faster than the best 802.11n solutions (about 1.3 Gbits/sec vs. 433 Mbits/sec).

This January the IEEE Standards Board (IEEE-SA) approved a new wireless standard designated IEEE 802.11ad, commonly referred to as "WiGig," using the 60 GHz band. It can achieve a theoretical maximum throughput of up to 7 Gbit/sec, a fast enough data rate to efficiently transfer uncompressed streaming video. First products utilizing this standard are expected to reach the market early next year.

The IEEE 802.11ad specification also adds a "fast session transfer" feature, which enables wireless devices to seamlessly transition between the 60 GHz frequency band and the legacy 2.4 GHz and 5 GHz bands. The ability to move between the bands ensures that computing devices are always best connected, enabling them to operate with optimal performance and range criteria.

Range is important here because the 60GHz frequency of 802.11ad is a two-edged sword. It makes the standard fast but is also the reason 802.11ad will not serve as a complete replacement for previous 802.11 versions. Rather, it is intended as more of a direct link between, say, various peripherals. Here's why: over long distances shorter wavelengths−higher frequency waves−tend to lose more energy than at lower frequencies and thus will be less effective at penetrating solid objects such as walls, bookcases and other furniture. At 60GHz attenuation is quite large, so 802.11ad technology will be mainly suitable for short-distance line of sight type of data transmission. Consequently, 802.11ad is not destined to become a replacement for consumers' wireless networks, rather; the new standard is designed to complement existing Wi-Fi networks by providing a multi-gigabit direct link between devices in the same room. That does make it well suited for the M-2-M part of IoT applications.

What's next? Rapid development in Internet-of-Things communication makes it necessary to design systems operating in different wireless spectrum than the current, highly congested wireless space. An IEEE standardization task group is developing an ultra-low-power specification running at the sub-1-GHz ISM (Industrial, Scientific, and Medical) band called IEEE. 802.11ah. The standard is being crafted to have a much wider range than the 2.4-GHz 802.11n or 5-GHz 802.11ac technologies. Aimed to help Wi-Fi-enabled devices get guaranteed access for short-burst data transmissions (such as for smart meter data). Its improved coverage range should permit new applications to emerge such as wide area based sensor networks. Its low power target also will make 802.11ah attractive for IoT use. IEEE 802.11ah is still in its preliminary stages.