Samsung All Cast dongle. On Amazon for like $50. DOES NOT use external wifi. It creates a wifi connection between it and your phone. It mirrors your phone screen. Don't forget to turn down the brightness while. mirroring, it doesn't affect the TV picture when is turned way down. I use mine every night to watch Hulu, Netflix and Amazon Prime for hours at a time.
You are referring to the Samsung Allshare Cast Dongle? The product description I saw on Amazon doesn't include the Note 5. I have a similar dongle made by NetGear that is suppose to perform the same function and it works on all my Samsung devices with the exception of the Note 5.
But if this dongle works specifically with the Note 5 I'm interested.
I use the Amazon Firestick from best buy. I think it was like 35 bucks. It allows me to mirror my phone to the tv in my 18 wheeler. It doesnt require wifi after the initial setup. I stream netflix and amazon movies to my tv every day.