It was his father calling him.
Yes, Ye Jiang was his father, and apart from being his father, that man was also a legendary badminton athlete in the country, and everyone in the country probably knew him even if they only heard his name.
Ye Jiang was an athlete in the men's singles sector many years ago, and he managed to win so many titles, including how he managed to win a gold medal at the Olympics which solidified his position as the world's number one athlete in the men's singles sector.
The reason why Ye Quan finally became a badminton athlete was his father. Being a legend in the country, Ye Jiang seemed to want to maintain his pride even after he retired, and that was why after his first son was born, he encouraged his son to go to the same field as him as an athlete in the men's singles sector.