In this paper, we propose three Deflection-Routing-based Multicast (DRM) schemes for a bufferless NoC. The DRM scheme without packets replication (DRM_noPR) sends multicast packet through a non-deterministic path. The DRM schemes with adaptive packets replication (DRM_PR_src and DRM_PR_all) replicate multicast packets at the source or intermediate node according to the destination position and the state of output ports to reduce the average multicast latency. We also provide fault-tolerant supporting in these schemes through a reinforcement-learning-based method to reconfigure the routing table to tolerate permanent faulty links in the network. Simulation results illustrate that the DRM_PR_all scheme achieves 41%, 43% and 37% less latency on average than that of the DRM_noPR scheme and 27%, 29% and 25% less latency on average than that of the DRM_PR_src scheme under three synthetic traffic patterns respectively. In addition, all three fault-tolerant DRM schemes achieve acceptable performance degradation at various link fault rates without any packet lost.

Credit-based router-to-router flow control is one main link-level flow control mechanism proposed for Networks on Chip (NoCs). Based on network calculus, we analyze its performance and optimal buffer size. To model the feedback control behavior due to credits, we introduce a virtual network service element called flow controller. Then we derive its service curve, and further the system service curve. In addition, we give and prove a theorem that determines the optimal buffer size guaranteeing the maximum system service curve. Moreover, assuming the latency-rate server model for routers, we give closed-form formulas to calculate the flit delay bound and optimal buffer size. Our experiments with real on-chip traffic traces validate that our analysis is correct; delay bounds are tight and the optimal buffer size is exact.

In dense passive radio frequency identification (RFID) systems, code division multiple access (CDMA) techniques can be used to alleviate severe collisions and thus enhance the system performance. However, conventional CDMA techniques are challenging to implement, especially for passive tags due to cost and power constraints. In this paper, we design a CDMA-based multi-reader passive ultra high frequency (UHF) RFID system in which a reader detects only the strongest tag signal and a tag uses Gold codes only on the preamble and the data bits of RN16 without increasing its clock frequency. We present a new communication procedure based on dynamic framed slotted ALOHA (DFSA). In order to optimize the system, we theoretically analyze the system performance in terms of slot capacity and identification rate, and formally show how the code length and the number of readers affect the identification rate. Furthermore, we propose an effective method for tag estimation and frame size adjustment, and validate it via simulations. Through an example, we demonstrate how the analysis-based technique can be used to optimize the system configurations with respect to the number of readers and the number and length of Gold codes.

In this paper, we propose a 1-cycle high-performance 3D bufferless router with a 3-stage permutation network. The proposed router utilizes the 3-stage permutation network instead of the serialized switch allocator and 77 crossbar to achieve the frequency of 1.25 GHz in TSMC 65 nm technology. Compared with the other two 3D bufferless routers, the proposed router occupies less area and consumes less power consumption. Simulation results under both synthetic and application workloads illustrate that the proposed router achieves less average packet latency than the other two 3D bufferless routers.

We investigate per-flow flit and packet worst-case delay bounds in on-chip wormhole networks. Such investigation is essential in order to provide guarantees under worst-case conditions in cost-constrained systems, as required by many hard real-time embedded applications. We first propose analysis models for flow control, link and buffer sharing. Based on these analysis models, we obtain an open-ended service analysis model capturing the combined effect of flow control, link and buffer sharing. With the service analysis model, we compute equivalent service curves for individual flows, and then derive their flit and packet delay bounds. Our experimental results verify that our analytical bounds are correct and tight.