AT&T, for example, on Thursday , up 2.1 percent from a year earlier, though profit declined from $2.8 billion to $1.2 billion due to one-time expenses. Revenue derived from its iPhone business helped boost revenue. The big question for AT&T is whether losing its status as exclusive operator for the iPhone will dampen subscriber growth.

Verizon, which will start selling iPhones next month, on Tuesday , down from $27.1 billion a year earlier, although net income nearly doubled to $4.6 billion. The revenue number was hurt because the year-earlier figure included sales from discontinued Verizon telephone operations in 14 rural states. Excluding revenue from those rural states, income rose 2.3 percent.

In a sign of continued strength for the mobile sector, Verizon said it added 803,000 wireless retail customers during the quarter.

Nokia, the world's largest maker of mobile phones by shipment volume, reported Thursday that year on year to €12.7 billion (US$17.4 billion ), but profit dropped from €948 million to €745 million. The problem is that the company is struggling in the higher-margin smartphone segment and needs to come up with an answer to the iPhone.

Motorola Mobility, in its first quarterly financial report since spinning off from Motorola, underscored how tough the smartphone market is. On a pro forma basis, Motorola Mobility's net income was $80 million, compared with a loss of $204 million a year earlier, and revenue was $3.4 billion, up 21 percent. But the company forecast a net loss of $26 million to $62 million for the current quarter. Motorola, which sells Android devices, said it is already suffering from competition from pre-orders of the Verizon iPhone.