How get Joystick value from Transmitter?

Hardware:
2 Arduino UNO
2 Arduino Wireless SD Shield
1 Arduino Motor Shield
1 SaintSmart Joystick
2 XBEE S1

How get Joystick value from Transmitter? My does not work.

Transmitter (simple code)

int VRx = A4;
int valx;
int joyValx;
int fspeed; // Forward speed
int bspeed; // Backward speed

void setup() {
  Serial.begin(9600);
}

void loop() {
  joyValx = analogRead(A4);
  
  if (joyValx >= 500 && joyValx <= 505) {
    Serial.write('s'); // Motor stop
  }
  
  if (joyValx < 500) {
    fspeed = map(joyValx, 500, 0, 0, 255);
    Serial.write(fspeed);
  }
  
  if (joyValx > 505) {
    bspeed = map(joyValx, 505, 1023, 0, 255);
    Serial.write(bspeed);
  }
  
  delay(100);
}

Receiver (simple code)

// Arduino Motor Shield
#define PWM_A 3
#define BRAKE_A 9
#define DIR_A 12

int fspeed;
int bspeed;

void setup() {
  Serial.begin(9600);
  pinMode(PWM_A, OUTPUT);
  pinMode(BRAKE_A, OUTPUT);
  pinMode(DIR_A, OUTPUT);
}

void loop() {
  while(Serial.available()){
    char getData = Serial.read();
    {
      if (getData == fspeed) {
        Forward();
      }
      
      if (getData == bspeed) {
        Backward();
      }
      
      if (getData == 's') {
        Brake();
      }
    }
  }
}

void Forward() {
  digitalWrite(DIR_A, HIGH);
  digitalWrite(BRAKE_A, LOW);
  analogWrite(PWM_A, fspeed);
}

void Backward() {
  digitalWrite(DIR_A, LOW);
  digitalWrite(BRAKE_A, LOW);
  analogWrite(PWM_A, bspeed);
}

void Brake() {
  digitalWrite(BRAKE_A, HIGH);
  analogWrite(PWM_A, 0);
}

From the receiver part:

      if (getData == fspeed) {

fspeed is a not initialized variable as is bspeed a few lines below. Do you really expect that this comparison does something useful?