Why Modern Buildings Still Have Wifi Dead Zones? And How One Fixed Them?

These days, expectation for always-on Internet connectivity is at the highest it has ever been. Much of the world in which we live and play, however, wasn’t designed for this level of persistent connectivity, and despite our best efforts, it can be difficult to get and remain fully connected for many reasons related to the number and position of radio antennae used to deliver the Internet to end-users

It is reasonable to understand that the architecture and construction of older buildings did not account for them having to support the complicated physics of multiple wireless access points. Perhaps, to no great surprise, the problem isn’t confined to old buildings as modern buildings sometimes must also be retrofitted for Wi-Fi Internet access. Our example case today is the newly designed headquarters for China Central Television (CCTV) in Beijing. During the 2012 move into their new offices, employees discovered that wireless access was erratic and unstable.

Unique design

Shaped like a continuous loop consisting of six different parts, the CCTV building has a different look depending on the direction from which it is viewed. It is one of the most architecturally unique buildings in the world. At its base are two 60-degree towers connected by a cantilever with a 90-degree angle in the middle. The result is an L-shaped Möbius Strip that appears to defy gravity because there is no direct support beneath the massive overhang.

The building, designed by architects Rem Koolhaus and Ole Scheeren of the Dutch firm OMA, serves as headquarters for China’s state broadcasting system and houses approximately 10,000 employees, 25 television studios, and a total floor area of over 5 million square feet.

CCTV wanted to provide Wi-Fi throughout the entire building for its employees to use for work and entertainment. However, due to the unique design of the building and multiple dead zones, particularly in elevators and high-density areas such as studios and newsrooms, Wi-Fi signal transmission was marginal.

“[CCTV employees] felt that they could use better Wi-Fi access,” said Jane Fu, WLAN Product Director for Huawei’s Switch and Enterprise Communications product line. “The free Wi-Fi was not satisfactory and they complained about the signal.”

CCTV partnered with Huawei to resolve the wireless LAN issues. The challenge for Huawei was meeting the CCTV requirement that the new wireless network have no blind spots in the building — including elevators, studios, and newsrooms. All areas of the building were expected to maintain good access without failing under the pressure of multiple users.

Design challenges

The irregular design of the CCTV building, which contains steel, reinforced concrete, and special glass, “makes communications and transmissions of signals difficult,” said Fu.

Chris DePuy, Vice President, Wireless LAN of the Dell’Oro Group research firm, agreed that concrete and glass hinders wireless network performance. “It’s really tough to penetrate a wall like that. If you’ve got cool architectural features like windows, some of them just stop the signal,” he said.

The Huawei team designed separate network plans for different zones inside the building. For example, areas with frequent high-density use and multiple users, such as the television studios, were equipped with stronger signals than were provisioned for single-person offices or hallways.

Fu said that special cables and antennas were placed throughout the building, including the elevators, to ensure access points would cover every area. DePuy said that it is common to use different kinds of antennas to provide directional coverage in areas where one antenna cannot provide the usual 360-degree coverage. Two or three antennas may be used to push signals in one direction to fill out the gaps between access points, he said.

The CCTV Wi-Fi project, slated for a January 2015 completion, has taken about a year. While the average building system typically deploys 100 to 200 access points, Fu said the CCTV building has required approximately 1,300 nodes.

Raising the bar

Jane Fu said that, although Huawei has extensive experience with deploying Wi-Fi networks covering large areas, such as sports arenas and universities, the CCTV project has helped the company establish a strong offer for other media companies. Fu says that, after completing the CCTV project, Huawei is now familiar with the Wi-Fi requirements necessary to support large studio and broadcast production complexes that the company can consider developing special solutions that are geared for the media industry.

“With this project, we have experience with irregular office buildings and the media industry, which will help us in the future,” she said.