I tried to define hotkey as following
(global-set-key [(control shift up)] 'other-window)
but it doesn't work (no error, just doesn't work), neither does
(global-set-key [(control shift down)] 'other-window)
But
(global-set-key [(control shift right)] 'other-window)
and
(global-set-key [(control shift left)] 'other-window)
work!
But because the last two key combinations are used by emacs (as default), I don't wanna change them for other functions.
So how could I make control-shift-up and control-shift-down work?
I have googled "(control shift up)", it seems that control-shift-up is used by other people, (but not very few results).
The reason for this is not an Emacs problem, but comes from the fact that your terminal cannot produce a key sequence for C-S-up.
You can verify this very easily. Open a terminal and then type:
Control-v Control-Shift-right
The Control-v part will make the control sequence for the next key be inserted verbatim into your shell. In our case, it will insert the sequence for Control-Shift right, and that'll look something like this:
^[[1;6C
Now, try the same thing for C-S-up:
Control-v Control-Shift-up
You'll see that no control sequence is entered, which hints at the fact that when you press C-S-up in Emacs, it will actually never receive anything, because the terminal is not able to produce anything to pass on to Emacs.
We can double-verify this if you just start a new emacs -nw and type C-h k to invoke Emacs' describe-key function. You'll get asked in the minibuffer to type a key to see what function it is bound to. If you now type C-S-up nothing happens - of course not, since the terminal in which your Emacs runs doesn't produce anything.
However, if you're just looking for an unused key-combination, how about just Shift-up (or even Shift-right) without Control? That one should work both in a terminal emacs and in the windowed version.