OVSF

I just found out that when the mobile node is trying to connect to the base station. The basestation will allocate a code. This code is allocated from a binary tree called Orthogonal variable spreading factor (OVSF). It is a unique code that allows to differentiate each user on the same resource. It is like two persons talking to each other in a noisy and crowded area. Only the two persons can understand and hear each other because of them has the unique code that have been allocated. The people around of them only hear background noise.