LTE to Wi-Fi offloading is driving IEEE's 802.11HEW effort

When it comes to Wi-Fi advancements, a lot of the focus over the years has been on improving maximum data speeds. But IEEE's 802.11HEW initiative is a taking a different tack in that it is targeting enhancements to the efficiency and performance of wireless local area networks to make them even better complements to LTE-based mobile networks.

802.11HEW--the HEW stands for high-efficiency WLAN--officially advanced to the study group (SG) stage at IEEE this past July after receiving approval from the IEEE 802 EC in March. Three meetings have been held regarding the initiative, with the most recent one taking place during September in Nanjing, China.

Bruce Kraemer, IEEE


IEEE is targeting ways to enhance the 802.11 PHY (physical layer) and MAC (media access control) in 2.4 GHz and 5 GHz spectrum with a focus on improving real-world, rather than theoretical, spectrum efficiency and area throughput. It is also aiming to improve the performance of indoor and outdoor deployments in the presence of interfering sources and dense heterogeneous networks in moderate to heavy user-loaded access points.

The major driver behind 802.11HEW is "carrier offload," said Bruce Kraemer, who is senior manager for strategic marketing at chipmaker Marvell Technology Group and also serves as a member of IEEE's board of governors and chairs IEEE 802.11. He stressed that his comments to FierceWirelessTech regarding 802.11HEW represent his views rather than IEEE's.

The mission behind 802.11HEW is to improve the behavior, capabilities and feature set of 802.11 "to make it a friendly option for LTE going forward" and "improve offloading from licensed cellular networks to unlicensed Wi-Fi networks," Kraemer added.

Veli-Pekka Ketonen, 7Signal


According to Veli-Pekka Ketonen, CTO of 7signal Solutions, which provides performance optimization for WLAN applications, "The past standardization work has been very much focused on increasing the maximum speeds, maximum capabilities. This new standard is not so much about improving maximum speeds but improving the practical use and experience."

He added that, "in real-life situations there has to be a better way to handle how access points and radios interact to use all the capabilities of the radios."

Laying the groudwork

French telco Orange was a key driver behind the creation of 802.11HEW, pushing to make 802.11 technology the best complementary pairing with LTE given that Wi-Fi really was not designed for the kinds of dense deployments many mobile operators are envisioning. Many other companies, such as Huawei, Broadcom, Qualcomm (NASDAQ:QCOM), China Mobile and NTT DoCoMo, quickly hopped on the bandwagon.

Kraemer explained that various carriers and vendors made presentations for almost a year prior to creation of the 802.11HEW SG, which is chartered to write a project authorization request (PAR) and provide market justification for the project to progress. That is a precursor to formation of a task group (TG), which will write a new technical standard. If the process stays on track, sometime during spring 2014 there will be enough clarity regarding 802.11HEW's mission to get approval from IEEE to form the TG, which could start its work in June or July.

IEEE performance user experience

Performance vs. user experience (Source: Veli-Pekka Ketonen / IEEE)

For now, the 802.11HEW SG is examining a bevy of proposed use cases, through which it hopes to ascertain what service providers will deliver and what end users will receive in terms of feature sets and benefits. "That guarantees that we've got a pretty clear picture of what the market wants from the standard," Kraemer said.

802.11HEW environments

Chart: 802.11HEW environments (click to enlarge)

Ketonen observed that he would like to see the 802.11HEW effort be broadened to address what he sees as looming issues in the Wi-Fi arena.

He suggested the Wi-Fi Alliance, which certifies interoperability of WLAN products based on IEEE 802.11, could "initiate some relevant industry initiatives" to support the overall 802.11HEW agenda and get ahead of expected problems. For example, he said the alliance could work toward encouraging agreement on retiring the aging 802.11b standard because, he contends, the co-existence of that standard significantly slows all other traffic. He also would like to see more stringent spectrum efficiency obligations applied to vendors, such as requirements for rate control operation to avoid excessive amounts of retries.

At this point, however, the Wi-Fi Alliance is not yet heavily involved with 802.11HEW, though it will be contributing use-case comments via a liaison agreement between the two organizations. "We're actually going to start work to do that for HEW very soon," said Kelly Davis-Felner, marketing and program management director for the Wi-Fi Alliance.

"There isn't an official milestone where something goes from IEEE and we say 'OK, let's work on this,'" she noted, adding that "the HEW work is really early days."  

Nailing down specifics

There are numerous ways of describing the dense-deployment use cases and operating environments that 802.11HEW seeks to tackle. In a July presentation, Laurent Cariou named seven target environments: Enterprise, small office, public hotspots, outdoor hotspots, homes, campuses and transportation.

He also cited a number of new or enhanced applications that must be considered in relation to potential use cases. Some of the apps on the list include wearable devices, such as Google (NASDAQ:GOOG) Glass; Wi-Fi geo-location services; wireless docking; progressive streaming; user-generated content uploads and sharing; interactive multimedia and gaming; and real-time video analytics and augmented reality.

Kraemer noted one particularly intriguing stadium use case involves people using their smartphones for digital video feeds of an event--be it a football game or rock concert --provided by the event venue. Such feeds could enable viewers to use their phones to zoom in on a particular player or performer, for example. But such a scenario gets especially tricky when it comes to serving thousands of end users in one location.

"Any individual handset in a stadium or field can deliver what any individual user might expect. But put 10,000 of them in a close, confined area with multiple people sitting physically close by, and it becomes a much larger technical challenge. Ultimately that's the type of challenge we're trying to solve," Kraemer said.

He emphasized that 802.11HEW is not focused on apps per se. As with 802.11 and other members of the 802 standards family, 802.11HEW is continuing the tradition of targeting Layer 1 and Layer 2 of the radio device. "The applications are not something we would be addressing directly," Kraemer said.

Looking ahead

Not surprisingly, the desire to improve Wi-Fi quality of service in order to better enable successful cellular offloading is attracting a high degree of industry interest.

The 802.11HEW study group has already received almost 150 submissions, "which is a document submitted to 802.11 describing what someone thinks we should be discussing," Kraemer said. "The quantity of submissions over the course of six months has been notable and remarkable within 802.11," he added.

802.11HEW study group participants hope their work will ultimately lead to delivery of "a new radio capability that will really benefit and complement what's going on in the LTE world," Kraemer said.  "This is a project that carries a lot of visibility, a lot of potential commercial benefits and end-user benefits and has attracted a very large community of interested companies and engineers."

LTE to Wi-Fi offloading is driving IEEE's 802.11HEW effort