A typical problem is faced when solving the convolution sum of LTI system in discrete case. While one may argue that a graphical solution is possible by plotting x[k] followed by h[-k+n] and flipping it along the n axis to calculate y[n] at various times,

the process may be time consuming especially for non-causal systems.

Then it becomes necessary to solve the sum below:-

∑_(k=-∞)^(k=∞)▒〖x[k]h[n-k]=y[n]〗

My question is that " Are there any general technique for calculation of various limits of the composite function y[n]"

i.e y[n] consists of a no. of functions valid for various intervals or time limits.