From EE Times: Silicon Labs Juices Wi-Fi in IoT Portfolio
PARIS — Among wireless technologies powering Internet of Things (IoT) connectivity, Wi-Fi has been conspicuously absent from Silicon Labs’ IoT product portfolio — until now. The Austin, Texas, company is formally joining the Wi-Fi in-crowd with home-grown low-power Wi-Fi transceivers and Wi-Fi modules designed for battery-operated IoT devices. The company is making the announcement Monday (Feb. 26) at a trade show in Nürnberg, Germany.
Silicon Labs is touting its Wi-Fi solution’s “exceptionally low transmit (TX: 138 mA), and receive (RX: 48mA) power, along with 200 µA average Wi-Fi power consumption will enable ultra-low system power for IoT devices.”
Silicon Labs' WFM200 Wi-Fi Module (Source: Silicon Labs)
Daniel Cooley, senior vice president and general manager of IoT products at Silicon Labs, told us, “We’ve been thinking of how to enter the Wi-Fi market, when to do it and what makes sense for us to do it,” especially after “tons of money already invested into Wi-Fi chip companies over the last 20 years.”
Wi-Fi for battery operated devices
So, why Wi-Fi now?
First, this is all about ubiquity. Wi-Fi is the most widely deployed wireless technology in the world, said Cooley. “When a consumer walks into McDonald’s, he expects to have a Big Mac and Wi-Fi,” he said. More specifically, Wi-Fi access points are already installed everywhere, he added.
Second, the IoT market is facing requirements to enable transmission of more and more data. “There are more IoT apps — like IP cameras — that need to pump a lot of data,” said Cooley. In parallel, those who build IoT systems also demand a fatter pipe for more frequent software updates, especially when patching security updates.
However, as IHS Markit’s senior analyst Christian Kim noted, despite Wi-Fi’s geographic spread, Wi-Fi’s high-power consumption compared to other wireless standards has “made it prohibitive for line-powered/battery powered applications” to embrace Wi-Fi on IoT devices.
Silicon Labs is hoping that a low-power Wi-Fi technology that meets the tight power budget of battery-operated devices will change the landscape.
IHS Markit predicts that the market for Wi-Fi devices in low-power IoT end-node applications to grow from 128 million units per year in 2016 to 584 million by 2021.
But now, given the glut of Wi-Fi chips on the market, how exactly will "Wi-Fi for IoT devices" differ?
Wi-Fi chips today “don’t respect network or data,” said Cooley. “Wi-Fi has notorious protocols that flood the network with packets. If the other device didn’t get a packet, it keeps chirping and chattering away — with no respect for the network where other wireless protocols exist.”
IHS Markit’s senior analyst Kim agreed. “Traditional Wi-Fi chips constantly connect to the network bringing the network performance down,” Kim said. Low-power apps need “low-power Wi-Fi chips,” he noted. The low-power Wi-Fi chips are designed to remain disconnected to the network and reconnect to the network only when the network has enough bandwdith available.
More specifically, “Clients will let go” of packets and try re-sending them later, said Cooley. Clients know effective throughputs, so once the network starts degrading, it backs off and lets others use the network. When it clears, it re-sends packets at a higher data rate. Cooley said, “Some access points manage the network better, as they started to embrace such flexible schemes.”
Silicon Labs also noted the company’s core RF performance improves the sensitivity and link budget of its Wi-Fi solution, resulting in a link budget of 115dBm for long-range Wi-Fi transmission.
Silicon Labs claims its new Wi-Fi devices “cut power consumption in half.”
Although a 50 percent reduction in power sounds great, the question is: Compared to whom? And where’s the proof? The IHS analyst rattled off a list of competitors in the low-power Wi-Fi chip space that includes Cypress Semiconductor, Texas Instruments and Microchip Technology (which acquired Atmel in 2016).
Silicon Labs, though not naming a specific competitor, shared the comparison table below. A company spokesman stressed, “The comparison is based on actual lab tests, chip to chip, and not data sheet specs.” Asked about the unsub in the table, he said, “The competitor has been around for a few years and they have made many public claims (like Cypress) about being the leading low-power Wi-Fi for IoT provider.”
Cooley also stressed the importance of the Wi-Fi SiP module for customers. “This 6.5 mm x 6.5 mm SiP includes antenna,” he said, “makes it possible for IoT system designers to add the Wi-Fi module to retrofit their existing IoT devices.” An added benefit of a SiP-based solution is reduced import/export taxes in some countries. SiP, technically, is considered a component, rather than a system with a printed circuit board.
Security for Wi-Fi
Last but hardly least, security is essential in every Wi-Fi chip. “We take security seriously,” Cooley intoned.
Fresh in not only Cooley’s memory, but throughout the tech industry is the scare of a massive Wi-Fi worm malware attack, known as Broadpwn, that took advantage of specific flaws in Broadcom’s Wi-Fi chips.
Last summer, both Google Android and Apple iOS had to scramble to patch a flaw that could have left all their users at risk from a critical remote exploit vulnerability. As experts noted then, Broadpwn was remarkable in its design as “a truly remote exploit.” The victim doesn’t have to do anything to be infected, the attacker doesn’t need to know anything about the target device, and the system under attack can be taken over without crashing.
A security expert at the Black Hat conference traced a vulnerability in Broadcom’s Wi-Fi chipset code. The flaw, as he explained, was a remotely exploitable “buffer overflow that could have enabled arbitrary code execution.”
It turns out, as Cooley noted, in many cases, there exists no encryption between a Wi-Fi transceiver and an application processor. Service-set identifiers (SSID) and password information were often left unencrypted. The serial link between a transceiver and a host processor also remained unprotected.
Cooley noted, “Data transferred between host processor and Silicon Labs’ Wi-Fi chip, for example, is safeguarded with Secure Link to protect information like SSIDs and passwords.” Likewise, firmware and code need to be authorized with secure boot. Silicon Labs’ Wi-Fi solution features advanced security technology, including secure boot and host interface, hardware cryptography acceleration supporting Advanced Encryption Standard (AES), Public Key Encryption (PKE) and True Random Number Generator (TRNG).
In the end, security will continue to dog IoT market growth. In this market, Over-the-Air (OTA) software updates and security patches will be SOP for IoT vendors in efforts to serve a broad customer base. But not each and every one of those IoT system vendors is a giant like Apple who can spend unlimited resources on security. Silicon Labs know that’s where a nimble little IoT chip company can find its niche.
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