laravel-backend/app/Events/RealTimeNotification.php

<?php

namespace App\Events;

use Illuminate\Broadcasting\Channel;
use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class RealTimeNotification implements ShouldBroadcast
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct()
    {
        //
    }

    public function broadcastWith()
    {
        return [
            'message' => 'mio test'
        ];
    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return \Illuminate\Broadcasting\Channel|array
     */
    public function broadcastOn()
    {
        // return new PrivateChannel('channel-name');
        return new channel('communications');
    }

    /**
     * The event's broadcast name.
     *
     * @return string
     */
    public function broadcastAs()
    {
        return 'global.message';
    }
}