For most consumers, the smartphone has become the PC replacement, a portable device that allows users to surf the Web, manage email and keep up with their favorite social media.
And yet, while the connectivity technology that powers that smartphone has improved over the years, it still lacks one critical feature that would put it on equal footing with the laptop or tablet PC: a 2×2 MIMO solution.
MIMO, or Multiple Input Multiple Output, is a wireless technology that’s found in some of today’s most popular devices, with the exception of smartphones, which have been unable to accommodate the large and power-hungry designs.
That’s about to change.
At Mobile World Congress this week, Broadcom unveiled the BCM4354, the industry’s first 5G WiFi, or 802.11ac 2×2 MIMO system-on-a-chip (SoC) for smartphones. The SoC enables smartphones to find and keep a clearer and more powerful Wi-Fi signal, essentially doubling wireless performance and widening coverage areas, while increasing system power efficiency.
For consumers, that means that their mobile Wi-Fi experience gets markedly better, enabling them to do things like send photos from crowded events (like a concert), eliminate “dead spots” where the router’s signal can’t reach in their homes, and get faster downloads and Web surfing while on the go.
Doubling Throughput with MIMO
2×2 MIMO (pronounced My-Mo) “uses two antennas to transmit and receive two streams of data at the same time, so it effectively doubles throughput,” explained Dino Bekis, vice president of product marketing, Mobile Wireless Connectivity Combos, at Broadcom.
Those antennas, which send out parallel signals, can also be configured to deliver the same throughput at a greater distance. That increases the chances of getting a signal in challenging, congested environments – like connecting from the basement to a router stuffed in an upstairs closet, or in a busy city environment jammed with interference from other people and objects.
Making do with single-antenna connection, which is found in most smartphones today, means that Wi-Fi reliability takes a hit. In some cases, that connection can be impacted by how and where people physically hold their devices. Bekis compares the experience to listening to an old single-speaker audio system player placed behind a couch, versus a modern home theater system. “With the latter, even if one of the speakers is blocked, you can still enjoy the music,” he said.
MIMO, by contrast, uses multipath communication to increase the likelihood of a strong Wi-Fi signal, regardless of how the phone is held or the obstacles that might be in the way. Under the hood, multiple signals are converted into a single, clear channel.
And because it uses 5G WiFi, the BCM4354 has a beam-forming capability, which means that it dynamically senses the environment for transmitting Wi-Fi signals and steers the beams to a specific device. This is done through a “handshaking protocol” that allows the device and router to communicate about where to send the signal.
Speedy, glitch-free uploads are important as smartphone users increasingly treat those handheld devices as the hub of their digital life, transmitting and receiving a steady flow of data, whether that’s a video being uploaded to YouTube or Facebook or content being streamed to a big-screen TV.
More obvious is the improved connectivity in crowded venues – such as concerts and sporting events – where large groups of people are simultaneously tapping a single Wi-Fi network with their devices. MIMO helps the signal fight through the congestion, which allows users to experience faster uploads and downloads.
How Broadcom Made It Work
Separating or electronically isolating antennas in the constrained spaces of small devices such as smartphones can be tricky and required some engineering heavy lifting, Bekis said.
To engineer the BCM4354, Broadcom had to break through several technological challenges, from making sure that MIMO antennas didn’t adversely affect battery life to fitting the new chip into a footprint comparable to existing single antenna solutions. Even as smartphone screens continue to grow, it seems, the space available for the phones’ inner workings continues to shrink.
It took a lot of proprietary enhancements to the radio design, Bekis says, to compensate for the less-than-ideal antenna conditions in a tightly packed smartphone environment. The result is a 2×2 MIMO SoC solution that works just as well as those on tablets and laptops.
In the Real World
Bringing 5G WiFi with 2×2 MIMO to smartphones will also make carriers and device makers happy, Bekis said.
For cellular carriers— who are in the business of getting more data-rich content to more consumers—2×2 MIMO means a hefty performance boost and improving energy efficiency 25 percent. They’ll get more ability to offload network traffic from their 3G and LTE networks to Wi-Fi while giving consumers a better experience on their devices.
Wi-Fi offload in the past consumed more power than voice over LTE, Bekis said, but 5G WiFi MIMO makes those connections more effective while using less power.
Carriers will also get more out of their managed Wi-Fi networks and hot-spots in big public spaces, such as sports arenas and concert venues, where the quality of the Wi-Fi network is sure to be noticed by thousands of people uploading and sharing content in real-time.
Mobile device makers, meanwhile, will be able to claim uniform Wi-Fi performance regardless of platform and will be free to develop innovative new form factors without compromising connectivity.
The BCM4354 supports Android, Windows and Chrome-based operating systems. There’s even a version that supports Rezence™ wireless power technology, developed by the Alliance for Wireless Power (A4WP). Now sampling, the chip joins a wide array of Broadcom MIMO solutions.
Bekis said he expects the first MIMO-equipped smartphones to be announced this quarter, with mainstream availability by summer.