The new operating system will have a particularly difficult mission: to break the duopoly held by Apple's iOS and Google's Android systems. It's not the first company to try this. In the past Blackberry's system, Microsoft's Windows Phone and Amazon's Fire have tried but failed.
The world's largest supplier of equipment for telecommunications stations and other network equipment, Huawei entered the mobile phone business in 2003, using Android. It has become one of the world's biggest mobile phone makers along with Samsung and Apple - briefly occupying the top spot last year - driven by demand and sales in emerging markets.
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And in Romania, the company has an important market share in terms of mobile phones. According to data from Canalys, it ranks fifth in terms of sales in the first quarter. The first in the country is Samsung, followed by Xiaomi, Apple and OPPO.
The sanctions imposed on the US company mean that Huawei phones come without Google services or applications such as Facebook, Instagram, Twitter.
Analysts say the immediate challenge for the new system from Huawei is applications. The company will have to convince enough developers to reprogram their apps to run on the Harmony OS.
Analysts say the app issue should not affect the domestic market. Huawei has a huge market share and its own menu of applications, which are mostly designed for Chinese users. But its global prospects may fade if negotiations with application developers do not yield the desired results.
Huawei under sanctions
Access for Huawei products to essential American technologies, including Google mobile services and some computer chips needed to power its devices, is limited after the US blacklisted it. The US government has accused Huawei of aiding China in espionage - a charge the company vehemently denies.
The inclusion of Huawei on the blacklist has restricted the business that American companies can do with the Chinese manufacturer of telecommunications equipment and smartphones. The move was a blow to Huawei, which has relied on US technology.
The sanctions also hit sales of the campaign, which dropped out of the top five worldwide last year, according to market research company Canalys. Huawei currently ranks seventh globally and third in China, after a 50% drop in smartphone shipments in the first quarter of this year compared to last year.