Problem on recieving data through serial communication on arduino

I have connected a Delfino (TI) F28335 and Arduino uno through uart. I am checking Data sent through Delfino and data received on Arduino using docklight in seperate computers. Though the data sent from delfino is correct , the data received by the Arduino isnt proper. The baud rate is 9600 for both. I have attached the code for arduino. Please help.

#include <SoftwareSerial.h>

SoftwareSerial gtSerial(8, 7); // Arduino RX, Arduino TX

void setup() {
Serial.begin(9600); // serial / USB port
gtSerial.begin(9600); // software serial port
}

byte rx_byte = 0; // stores received byte

void loop() {
// check if byte available from USB port
if (Serial.available()) {
rx_byte = Serial.read();
// send a byte to the software serial port
gtSerial.write(rx_byte);
}

// check if byte available on the software serial port
if (gtSerial.available()) {
// get the byte from the software serial port
rx_byte = gtSerial.read();
Serial.write(rx_byte);
}
}

Your code looks good, so far. Most problems with serial transmission result from missing Gnd connections, and unmatched signal levels. The Arduino expects 5V (TTL) levels on the Rx/Tx lines.