Chinese companies Guangdong Mobile and Guangxi Mobile have signed a deal, valued at close to $290 million, for Ericsson ( ERICY) to expand their GSM networks.

Sweden's Ericsson said in a statement on its Web site that it will supply core and radio access network equipment, including hardware, software and telecom services.

Once they're completed, the expansions will boost the network capacity of Guangdong Mobile to more than 60 million subscribers and Guangxi Mobile to nearly 10 million.

Ericsson was lower by 61 cents, or 1.8%, to $34.11 in premarket trading.