State observer controller design for packets flow control in networks-on-chip

Packet-switched networks-on-chips (NoCs) are efficient communication architectures for future multiprocessors system-on-chip (MP-SoC) platforms. However the run-time management of their communication, especially flow control from individual intellectual property (IP) in an NoC which contains large number of IPs, is a challenging task. This paper proposes a state space model for NoC with state observer controller in its feedback path. It is seen that controlling the input and output flow rates alone is not sufficient to stabilize the network, but it is also important to monitor the intermediate flow rates from the on-chip routers. This is possible through a state space model for the NoC. The state observer observes the flow rates from each on-chip router which are then treated as state space variables. These variables can be controlled by the poles placement in the feedback controller. The proposed mathematical model can also observe the required intermediate flow rates which cannot be measured directly (reduced state observer). With these observed states we can attach a state controller. With this controller the network can be stabilized by controlling the flow rates at the intermediate level.