Matrix Exponential Distribution Method Applied to Multi-RIS Aided Systems Evaluation

The sum of random variables arises as a challenge in several wireless communication problems, particularly those characterized by the Fox H distribution. In this paper, we derive the moment generating function (MGF) of the sum of independent and non identically distributed (INID) Fox H random variables and apply the matrix exponential distribution method (MEDM) to obtain the probability distribution of this sum and to derive performance metrics such as outage probability (OP), average symbol error probability (ASEP) and normalized ergodic capacity (EC) in a wireless communication system assisted by multiple reconfigurable intelligent surfaces (RIS).