Microsoft has announced that all Windows Phone 7-based smartphones will only be compatible with GSM mobile networks until 2011.
The software giant said that CDMA support will come next year.
This means that Windows Phone 7 will not be available on Verizon Wireless and Sprint Nextel until next year.
CDMA mobile technology is supported by AT&T and T-Mobile along with other European mobile services providers.
According to Greg Sullivan, the senior product manager at Microsoft, the company decided to initially go for GSM support because it wanted to give priority to "high-quality" customer experience above all else.
The CDMA version of Windows Phone 7 will be released during the first half of 2011.
Although Microsoft has not revealed the launch details of the first Windows Phone 7 device, analysts predict that the company will launch it next month.
Windows Phone 7 is in for tough competition as it will go into direct competition with Apple's iOS and Google's Android OS in order to make a name for it self in the smartphone market.