Please note that when you are working on GPRS, there is at least two kinds of GPRS modems available.
One is just a raw wireless modem that you need to implement all the necessary protocol in your MCU, like the PPP, LCP, IPCP, IP, TCP or UDP ...
The other is with TCP/IP Stack, which you can simple connect the server side by AT command. This can help to save both development time, and also the resource of the MCU.
Many GPRS module manufacturer has both modems, like Siemens, Sony Ericsson, BenQ, Wavecom ...
However, no matter which modems you will use, I found that you are targeting to do both Client (Vehicle) and Server (Base Station). Please note that some operater will provide you a virtual IP that is hardly be visited by other parties, this will cause a problem on the server side, which will act as hidden behind a firewall.
Regards
Added after 50 seconds:
Please note that when you are working on GPRS, there is at least two kinds of GPRS modems available.
One is just a raw wireless modem that you need to implement all the necessary protocol in your MCU, like the PPP, LCP, IPCP, IP, TCP or UDP ...
The other is with TCP/IP Stack, which you can simple connect the server side by AT command. This can help to save both development time, and also the resource of the MCU.
Many GPRS module manufacturer has both modems, like Siemens, Sony Ericsson, BenQ, Wavecom ...
However, no matter which modems you will use, I found that you are targeting to do both Client (Vehicle) and Server (Base Station). Please note that some operater will provide you a virtual IP that is hardly be visited by other parties, this will cause a problem on the server side, which will act as hidden behind a firewall.
Regards