China Unicom (Hong Kong) Ltd. said Sunday that it signed a deal with Telefonica, the Spanish telecom operator, to enhance their alliance by spending 1 billion U.S. dollars each on share purchase. China Unicom would acquire shares equal to about between 0.885 percent to 0.892 percent of stake in Telefonica, according to the company's statement to the Shanghai Stock Exchange. Telefonica would increase its stake in China Unicom from 5.38 percent to 8.06 percent, the statement said. Their cooperation would focus on infrastructure and equipment purchase, mobile service platforms, research and development, and service provision to multinational clients, according to the deal. 