How to solve the problem of getting "pdp deact" ?

hai,

I am working with sim548c i interfaced with micro controller.I use to send data from modem to server through gprs for every one minute.I establish connection to my server and send data to the server and after 20seconds i shut the connection by at+cipshut and after 40 seconds i establish connection and send data to the server.Some times i get +pdp deact

AT+CIPSTART="TCP","xxx.xxx.xxx.xx","5000"
OK

CONNECT FAIL

STATE: IP IND

+PDP: DEACT


AT+CIPSTATUS
OK

STATE: PDP DEACT


AT+CIPSHUT
STATE: PDP DEACT

SHUT OK


After at+cipshut I try to establish the connection by giving

AT+CIPSTART="TCP","xxx.xxx.xxx.xx","5000"
OK
CONNECT OK
and i send data no problem.After some minutes 3 to 4 minutes i get

AT+CIPSTART="TCP","xxx.xxx.xxx.xx","5000"
OK

CONNECT FAIL

STATE: IP IND

+PDP: DEACT


How can i over come from this problem.I checked antenna no problem in it.

Re: +pdp deact

When you get PDP DACT, it means u r disconnected.

So you have to again establish connection by issuing the
at+cgdcont = ....,"....","............................." [enter]
at+cdnscfg=" . . . " [enter]

at+cstt="........................","',"" [enter]

you shud get at+ciicr return as OK

then u can continue with ur at+cipstart command and at+cipsend