AT&T Wireless will delay the shutdown of its Cellular Digital Packet Data (CDPD) network until at least September 30 of this year, according to a report issued this week by UBS Financial Research. It had been expected that AT&T Wireless would shut down the network on June 30. UBS said it believes AT&T Wireless could push back the deadline even further because the carrier will be focused on its merger with Cingular Wireless.