“…Thus, the resource allocation problem can now be formulated as where U 0 is the system utility function. If we take into account the user traffic demand, without loss of the generality, the form of the satisfaction of user i can be defined as where R i denotes the achievable data rate for the user i and D i is the required transmission rate. Then, from the system optimisation point of view, we can have and problem can be transformed into …”