1. A method for monitoring a communication network, the method comprising: a first node of the communication network determining a hash-based sketch summarizing a number of occurrence of an event for a group of user equipments (UEs); the first node receiving information representing the number of occurrence of the event for said group of user equipments from a second node of the communication network; the first node updating the hash-based sketch with said information received from the second node; the first node providing the updated hash-based sketch to the at least one further node; and generating a statistic on a UE level for a specific UE based on the updated hash-based sketch; wherein the determining of hash-based sketch comprises: obtaining a matrix having a first row comprising a first plurality of cells and a second row comprising a second plurality of cells, wherein a first hash function is associated with the first row and a second hash function is associated with the second row; and for a specific UE from said group of UEs, utilizing the first hash function and an identifier unique to the specific UE to select a first cell from said first plurality of cells, storing a first counter value in the selected first cell, utilizing the second hash function and the identifier unique to the specific UE to select a second cell from said second plurality of cell, and storing a second counter value in the selected cell.