For clients of the U.S. mobile phone carrier Verizon this month had its own surprises. The carrier had problems with its wireless 3G and 4G network and clients could not connect to these networks. Verizon announced it has started an investigation on the 4G outage problem.

First outage occurred in the first week of December, as a number of users complained they were unable to connect to Verizon’s 4G network. Then, two weeks later, both 3G and 4G networks were reported to have problems. Now, users in all the major cities including Chicago, San Francisco and New York are experiencing similar problems.

Verizon released the media the following statement: “We are investigating reports of some customers experiencing trouble accessing the 4G LTE network”. The company also added that “the network itself continues to operate and all customers continue to be able to make calls, send text messages and utilize data services. 3G devices are operating normally”.

However the company neglected to explain what’s causing the outages or when the situation would be fixed. When the first outage occurred, the carrier took about a day and a half to resolve the outage. Then, last week it took solved even faster. “Verizon Wireless 4G LTE service is returning to normal this morning after company engineers worked to resolve an issue with the 4G network during the early morning hours today,” the company said in a statement.

Analysts are concerned that these three consecutive outages could damage Verizon’s popularity. Roger Entner, founder of the market research firm Recon Analytics, explained: “The big attraction for Verizon is its network superiority. People pay a premium for this superiority. But if that goes away, they are merely expensive”.

This August, J.D. Power and Associates said Verizon has the nation’s most reliable wireless network. U.S. 2011 Wireless Network Quality Performance Study–Volume 2 ranked Verizon as the top carrier in the Northeast for the 14th time in a row.

But, users should take into account the fact that Verizon is working to expand its 4G LTE network to boost speeds when moving data online. Entner said outages are likely caused by upgrades and patches to the network.