There are few steps which we have to follow to implement Push Notification.

Step 1: First we will write the api to get token and device type . Here is the controller code of push notification.

public function pushNotification() {
        $validator = Validator::make(Request::all(), [
                    'userId'=>'required',
                    'accessToken'=>'required',
                    'senderId'=>'required',
                    'token'=>'required',
                    'deviceType'=>'required'
        ]);
        if ($validator->fails()) {
            #display error if validation fails      

            $this->status = 'Validation fails';
            $this->message = 'arguments missing';
        } else {
            $userId =Request::get('userId');
            $accessToken=Request::get('accessToken');
            $senderId=Request::get('senderId');
            $token=Request::get('token');
            $deviceType=Request::get('deviceType');
            $checkUserStatus =User::where('id','=',$userId)->first();
            if(!empty($checkUserStatus)){
                if( $deviceType=='Android'){
                    $setMessage='You have a new activity on KarmaCircles.';
                    $pushNotificationStatus=NotificationHelper::androidPushNotification($token,$setMessage);
                    $this->status = $pushNotificationStatus;
                    $this->message = 'Push Notification Message';
                }else{
                    $pushNotificationStatus=NotificationHelper::iphonePushNotification($token,$setMessage);
                    $this->status = $pushNotificationStatus;
                    $this->message = 'Push Notification Message';
                }
            }else{
                $this->status = 'Failure';
                $this->message = 'There is no such user available';
            }
        }
        return Response::json(array(
            'status'=>$this->status,
            'message'=>$this->message
        ));
       }

Now we use NotificationHelper to perform notification.

Step 2:

In NotificationHelper.php the code is:

#======================================================================================
    /**
     * Android Push Notifications using Google Cloud Messaging (GCM)
     * Send push notification from web server to registered android devices.
     *
     * @param   array   data
     * @param   string  message
     * @param   array   custom_fields
     * @return  string  status
     */
    public static function androidPushNotification ($deviceToken, $setMessage = "Hello Android Rohit!"){
        // Set parameters:
        $apiKey = 'AIzaSyBgiOAHXJRTCbehKUprmqFS89ZuHZ0vTJQ'; // API key from Google Developer Console
        $gcmUrl = 'https://android.googleapis.com/gcm/send';

        // Get the device token (fetch from database for example):
        $regid  = $deviceToken;

        // Set message:
        $message = $setMessage;

        // Send message:
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $gcmUrl);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER,
            array(
                'Authorization: key=' . $apiKey,
                'Content-Type: application/json'
            )
        );
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode(
                array(
                    'registration_ids' => array($regid),
                    'data' => array(
                        'message' => $message
                    )
                ),
                JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP
            )
        );

        $result = curl_exec($ch);
        Log::info("curl result ::". var_;export($result,TRUE) );

        if ($result === FALSE){
            $status = 'failed: ' . curl_error($ch);
        }
        else
        {
            echo $status = 'success';
        }

        // Close connection
        curl_close($ch);
        Log::info("returning  ::". $status );

        return $status;
    }

By this way we can implementing push notification using laravel 4.x