The 802.11ac standard is well on its way to becoming the most widely used Wi-Fi standard, overtaking the legacy 802.11n standard this year in terms of device shipments. 802.11ac enabled devices that have shipped until now are mostly based on the 802.11ac Wave 1 specifications which include initial set of features from the 802.11ac standard. This year, growing numbers of smartphones are starting to include next set of features in the 802.11ac standard - commonly referred to as Wave 2. This trend is a leading indicator that can be used to assess the future adoption of the 802.11ac Wave 2 specifications across product categories.
This article will describe the advantages of the 802.11ac Wi-Fi standard compared to the legacy 802.11n standard. In addition, this article will examine the advantages of the MU-MIMO feature which is a hallmark feature of the 802.11 Wave 2 specifications. This article will also provide an overview of the IHS Markit forecast for 802.11ac Wave 2 (MU-MIMO) enabled smartphones.
In 2015, the 802.11n standard was the most popular Wi-Fi standard, shipping the greatest number of devices globally compared to any other Wi-Fi standard. However, the rising popularity of high-definition video streaming services and other broadband applications is demanding a new generation of Wi-Fi that can offer higher throughput, less crowded frequency bands and access points that can simultaneously transmit data to multiple client devices. 802.11ac is the latest Wi-Fi standard to gain popularity and it is expected to become the most widely used Wi-Fi standard for the next several years.
Below is a summary of some of the challenges faced by devices using the legacy 802.11n standard:
• Limited amount of throughput -- The PHY rate of a single stream 802.11n IC chipsets is typically advertised at 150 Mbps. This puts the average throughput of an 802.11n device to be well below 100 Mbps.
• Crowded 2.4 GHz frequency band -- Although there are 802.11n chipset solutions that support the 5 GHz frequency band, the majority of 802.11n Wi-Fi devices still operate in the 2.4 GHz band. The 2.4 GHz frequency band is widely used by Bluetooth devices and proprietary devices (such as mice and keyboards in PCs). Multiple devices operating in the crowded 2.4 GHz frequency band can cause channel overlap between devices, resulting in interference and reduction in throughput.
• Multiple client device connections -- A Wi-Fi access point based on the 802.11n standard can transmit data to one client device at a given time. This is not a problem when only one device is connected to an access point. However, when multiple devices are connected to a single access point at the same time, it results in reduced throughput to all the connected devices. This limitation has become a more critical issue recently, as the average number of Wi-Fi enabled devices in an average home is approaching ten devices.
In order to address the challenges posed by legacy Wi-Fi standards, product manufacturers have been gradually increasing shipments of 802.11ac Wi-Fi devices. The initial devices based on the 802.11ac standard resolved two challenges of the previous standard by:
• Increasing the throughput by approximately three times
• Providing full access to the less congested 5GHz frequency band
The majority of 802.11ac devices released over the past few years have been mainly based on 802.11ac Wave 1 specifications. Despite the new improvements made over the 802.11n standard, the features offered by Wave 1 specifications still did not address the issue of reduced throughput when multiple client devices are connected to a same access point.
Adoption of 802.11ac Wave 2 specifications
The 802.11ac Wave 2 contains the improved features from the 802.11ac Wave 1 specifications that addresses the problem of multiple client-device connections causing throughput reduction. One of the key features of the 802.11ac Wave 2 specifications, known as MU-MIMO, is that it gives access points the ability to simultaneously transmit data to multiple client devices. Simply put, client devices with MU-MIMO capability -- when connected to a MU-MIMO capable access point -- will maintain throughput, even when multiple devices connect to the same access point. It is worth mentioning that in order to use the MU-MIMO feature, both the access point and the client devices are required to have MU-MIMO support.
Since MU-MIMO requires support by both the access point and the client devices, mass adoption of both access points and client devices became the critical factor for the success of the Wave 2 specifications. For the past two years, Qualcomm has been strongly pushing for the mass adoption of 802.11ac Wave 2, by introducing various 802.11ac Wave 2 based connectivity chipsets for access points and client devices. Using Qualcomm’s Wave2 chipsets, device manufactures have released smartphones, tablets, laptops and other MU-MIMO-enabled devices. However, despite launching hundreds of different products across many product categories, MU-MIMO has not achieved significant shipment volume over the past two years. According to IHS Markit estimates, only 1.5 percent of total smartphone shipments had MU-MIMO support in 2015.
Despite a slow ramp up, there have been a few key developments in the market this year that are contributing to an accelerated adoption of the 802.11ac Wave 2 standard:
• Start of 802.11ac Wave 2 certification -- starting in late June 2016, the Wi-Fi Alliance started to offer 802.11ac Wave 2 certification. The addition of the Wave 2 certification ensures interoperability between chipsets manufactured by different vendors. Historically, new Wi-Fi certification offerings from the Wi-Fi Alliance have contributed to a wide market adoption, and the new certification program is expected to encourage more Wave 2-enabled products in the market.
• Participation from major IC vendors -- In addition to Qualcomm, Broadcom is now actively shipping 802.11ac Wave 2 chipsets. Samsung’s Galaxy S7, which launched early this year, supports 2X2 MU-MIMO and it used Broadcom’s first 802.11ac Wave 2 chipset for client devices. In addition to Broadcom, Mediatek is also expected to release its Wave 2 connectivity chipset for client devices before the end of the year.
• Popularity of high-definition streaming services – Netflix, Hulu, Amazon and other streaming video service providers have been steadily gaining subscribers over the past few years. These companies are now offering more streaming 4K video content, requiring higher data throughput than applications in the past.
MU-MIMO adoption in smartphone is progressing well
Below is a summary of recent smartphone launches that have contributed to rapid adoption of MU-MIMO functionality in smartphones:
• In March, Samsung released Galaxy S7, their first flagship smartphone of the year. The Galaxy S7 support 2x2 MU-MIMO connectivity. Since launch, Galaxy S7 has been posting strong shipment numbers.
• Major Chinese smartphone vendors -- such as Vivo (Xplay 5), OPPO (OnePlus 3) and ZTE (Axon 7) -- have launched MU-MIMO enabled flagship smartphones.
• Other smartphone vendors ASUS (ZenFone 3 Ultra), Lenovo (PHAB2 Pro) and Kyocera (DuraForce PRO) recently launched or are planning to launch MU-MIMO enabled smartphones this year.
Apple is the most significant remaining vendor that has yet to launch an MU-MIMO enabled smartphone. The specifications released from the recently announced iPhone 7 did not include MU-MIMO capability. With the wide adoption of MU-MIMO feature taking place, it is highly likely Apple will include MU-MIMO feature in its next version of iPhone in 2017.
In August, Samsung launched its second flagship smartphone of the year Galaxy Note 7 which also includes 2x2 MU-MIMO connectivity. However, due to discovery of smartphone overheating, Samsung subsequently recalled 2.5 million units of the Note 7 units sold to date. Due to the recall, the contribution of Samsung’s Galaxy Note 7 to overall MU-MIMO smartphone adoption rate is expected to be limited.
The table shown below is global smartphone shipments by WLAN version, including 802.11ac Wave 1 and Wave 2 smartphone shipments:
Graph 1: Global smartphone shipments by WLAN technology – 2015 to 2020
IHS Markit forecasts 802.11ac Wave 2 enabled global smartphone shipments will exceed 107 million units in 2016. This number accounts for nearly 7 percent of total global smartphone shipments in 2016 and represents almost 500 percent increase over the previous year. In 2017, MU-MIMO-enabled global smartphone shipments are expected to nearly double from the previous year to 200 million units.
With the strong increase in Wave 2 smartphone shipments now taking place, mass adoption of 802.11ac Wave 2 standard is just around the corner. After the adoption of smartphones, Wave 2 standard adoption is expected to further increase in other product categories, especially categories that require high data throughput such as tablets, laptops, high-definition TV, and digital media adaptors.
IHS Markit will include full coverage of 802.11ac Wave 2 adoption across 20 product categories in the upcoming report, WLAN Market Overview, to be published at the end of September 2016.