Barcelona (CNN Business) Over the next four days, about 100,000 people in Barcelona are expected to traipse through the halls of Mobile World Congress, one of the tech industry's biggest events. All the biggest players in the world use it to showcase new products.

One company really stands out this year: China's Huawei. Walking out of the Barcelona airport, there's a Huawei hospitality stand. The company's branding dots the city. The lanyards conference attendees wear around their necks are decorated with the Huawei name.

There's a good reason everyone is focused on Huawei, one of the world's largest makers of telecom equipment.

Huawei is a crucial part of China's efforts to advance superfast 5G wireless networks and today is caught in a life or death battle with the US government.

The United States claims that Huawei poses a potential national security threat. Last month, US prosecutors revealed criminal charges against the company, alleging that Huawei stole trade secrets and worked to skirt US sanctions on Iran.