The problem was that reasonable people argued that other techniques would work just as well as polar codes to achieve error correction in the new fram
The problem was that reasonable people argued that other techniques would work just as well as polar codes to achieve error correction in the new framework. Some suggested that a revamp of the current 4G protocol, turbo codes, would be sufficient. Others, notably San Diego-based Qualcomm, which makes chipsets for mobile technology, liked a third option: Robert Gallager’s old LDPC idea, the one that had nearly reached the Shannon limit and had inspired Arıkan on his own intellectual journey.
Since the early 1960s, when Gallager proposed LDPC, technology had improved and the cost of commercial production was no longer prohibitive. Qualcomm’s R&D team developed it for 5G. Though Erdal Arıkan did not know it at the time, his work would be squared off against that of his mentor in a competition that involved billions of dollars and an international clash of reputations.
One advantage Huawei had was the backing of its government. US and European observers say China packs standards meetings with engineers who can be eyes and ears on the ground. Rivals also complain that Chinese companies work together in lockstep; even ostensible competitors will set aside differences to support a compatriot business.
For a brief moment in the middle of 2016, it looked as if that national wall of support wouldn’t hold. In a preliminary round of the 5G New Radio standards process, the Chinese company Lenovo expressed its preference for LDPC, because it was a more familiar technology. That didn’t last long. Lenovo changed its opinion later that year. Lenovo’s founder, Liu Chuanzhi, called Ren Zhengfei to make sure that no offense was taken by the original stance. Liu and other executives even drafted an open letter that read like a forced confession. “We all agree that Chinese enterprises should be united and not be provoked by outsiders,” Liu and his colleagues wrote. “Stick to it … raise the banner of national industry, and finally defeat the international giants.”
Thus united behind polar codes, Chinese industry prepared to do battle at the final, critical stage—the November 2016 engineering standards meetings held in Reno, Nevada. The venue was the Peppermill resort and casino. Engineers, hunkered in hotel conference rooms arguing about block codes and channel capacity, had little time to enjoy the craps tables or eucalyptus steam rooms. Simultaneous meetings to determine a number of standards kept engineers hopping from one conference room to the next, says Michael Thelander, a consultant specializing in wireless telecommunications. “But polar coding versus LDPC, that was the hot topic,” he says.
On the night of Friday, November 18, the conference room was packed, and the meeting, which began in the evening, turned into a standoff. Each company presented its work, including its testing results. “The battle was pretty well drawn, with most of the Western vendors lining up behind LDPC,” says Kevin Krewell, a principal analyst at Tirias Research, who follows 5G. Some Western companies backed polar codes too, but, significantly, all the Chinese companies did. “There was no obvious winner in the whole game, but it was very clear that Huawei was not going to back down,” says Thelander, who was on the scene as an observer. Neither would the LDPC side. “So we can sit there and spend six months fighting over this thing and delay 5G, or we compromise.”
So they did. The standards committee split the signal-processing standard into two parts. One technology could be used to send the user data. The other would be applied to what was known as the control channel, which manages how that data moves. The first function was assigned to LDPC, and the second to polar codes. It was well into the wee hours when the agreement was finalized.
Huawei was ecstatic. But it was not just Huawei’s win; it was China’s too. Finally, a Chinese company was getting respect commensurate with its increasingly dominant power in the marketplace. “Huawei-backed polar code entering the 5G standard has a symbolic meaning,” one observer told a reporter at the time. “This is the first time a Chinese company has entered a telecommunications framework agreement, winning the right to be heard.”