Event-triggered feedback for power allocation in wireless networks

Transmission power control constitutes a core feature required to achieve a desired quality of service in wireless networks. A practical implementation calls on the intuition of using limited resources, only when are strictly required. Thus, the appeal of an event-triggered scheme arises naturally over more traditional, but less efficient, periodic time-triggered control solutions. Motivated by these ideas, the authors present here a power allocation strategy based on an event-triggered transmission (ETT) to reduce the feedback signalling in the network. The power allocation under ETT is based on a nominal control that guarantees internal stability and performance. Hence, if the feedback signalling does not change significantly from the previous sample, no feedback transmission is assigned to reduce bandwidth usage. Two schemes are employed to define the ETT while preserving closed-loop stability: a piecewise quadratic Lyapunov argument and a perturbed linear system approach. These two approaches establish a trade-off between complexity and conservativeness. The power allocation under ETT was thoroughly evaluated under two nominal control schemes to establish a relation between performance and feedback reduction.