You could do it, but if the concrete is unstable and settling and cracking, then it will continue to do so and you will have cracks in your tile grout. I personally wouldn't do it, but you could buy extra grout and whenever a crack appears, then dig out the cracked grout and regrout it. Go to one of the home cheapos and they have some DIY instructions. There are some on the web also if you want to do a search.
Sometimes the best route is to break up and remove the concrete. Then use a "compacted" gravel subbase for your new concrete or put in a wood deck. The compacted gravel subbase should help against settling. Two areas of concern are next to the foundation that may have been backfilled with sand which may have a different settle and compaction rate than your regular soil and some basements were built with a frontendloader who cuts a ramp to drive in and out of it which when backfilled settles differently (this happened on my house, part of the patio is above the former ramp and it cracked and settled over it). Good luck.