Interfacing STM32f103c8t6 with GSM800L

void init_GSM_Modem(void);

const char command_CMGF[]="AT+CMGF=1\r"; //Selecting text mode
const char CtrlZ =0x1A;

const char command_CMGS[]="AT+CMGS=+91989xxxxxxxx\r"; //Phone number to send message to

const char command_AT[]="AT\r";

const char msg01[]="Hello! This is a Test Message via STM32F107"; //Message to be sent

/* Leaving out init_serial, SendChar and GetChar Functions for reducing the code length. */

/*----------------------------------------------------------------------------
* init_GSM_Modem : Initialize Modem Commands
*---------------------------------------------------------------------------*/

void init_GSM_Modem(void)
{
delay2();

puts(command_AT);
delay2();

puts(command_CMGF);
delay2();

puts(command_CMGS);
delay2();

puts(msg01);
delay2();

while (!(USART2->SR & 0x0080));
USART2->SR & 0x0000;
USART2->DR = 0x1A; //sending CtrlZ command
}

int main(void)
{
SystemInit();

init_serial();
init_GSM_Modem();

while(1)
{;}
}

This code gives me an error named as error[PE020] : identifier 'USART 2' is not defined while working with it in IAR workbench. Please define me this error and a solution to it.