I believe I know what you're asking, and I asked about that on Command Blocks And Redstone, and HerobrineAC0318 replied,
I believe there will be a command added in 1.2 called /gamerule tickingarea. Use that to make “spawn chunks”. So no matter where you are, that chunk will always be loaded. Sorry if it sounds like I'm trying to take credit, it was all HerobrineAC0318.
Currently there is no spawn chunks in MCPE (or bedrock engine).
However, as ApplexForLife vaguely refers to, there will be a /tickingarea command, which enables the player to mark various areas to be kept loaded and to receive game ticks (which is the game mechanism related to triggering block updates, farm updating, redstone mechanims, command block updates and so on)