simple AsyncMacLayer
    parameters:
		coreDebug : numeric const, // debug switch for the core framework
		headerLength: numeric const, // length of the MAC packet header (in bits)
		rxEnergy: numeric,
		txEnergy: numeric,
		sleepEnergy: numeric,
        roundTime:numeric,
        dutyCycle:numeric,
		sleepTime: numeric,
		activeTime: numeric,
		alfa: numeric,
		delayIntTime: numeric,//pop up msg delay
		frameCapacity: numeric,
		bitrate: numeric,
		groupSize:numeric,
		retryLimit: numeric;
    gates:
		in: uppergateIn; // from the network layer
		out: uppergateOut; // to the network layer
		in: lowergateIn; // from the physical layer
		out: lowergateOut; // to the physical layer
endsimple