# Mapping of Deep Neural Network Accelerators on Wireless Multistage Interconnection NoCs
## 4 Design of Hybrid Network-on-Chip Based on Delta MINs  
In this section, the design flow of our advanced hybrid (Wired and Wireless) communication architecture based on Delta Multistage Interconnection Network is thoroughly detailed. The model is conceived to involve a number of relevant parameters, particularly, a special topology and structure, traffic model, dynamic behavior, and simulation. A set of metrics has been configured and evaluated. The model is implemented on the Noxim simulator. An extended version of Noxim is used, which includes radical improvements, related mainly to signals mapping, wireless communication within Delta MIN stages, and a specific routing algorithm to maintain flexible data transfer between cores (Figure 4). The Delta MIN has been implemented by adding new signal mapping using SystemC to allow for various network topologies to be constructed (e.g., Butterfly, Omega, and Baseline) (Figure 5). Another required extension has been the design of the switch nodes, necessary to manage routing alternatives in the network. After introducing the topology, necessary for maintaining connection between the links and switches, we proceed with  
Figure 4: Noxim Simulator Design Flow. incorporating radio nodes to enhance the wireless feature option throughout the Delta MIN networks. It is worth noting that wireless nodes represent switching components capable of exclusively maintaining a unique hop communication with distant switch nodes, which entails several hops to pass through a wired network configuration (Figure 6). Then, we resume by introducing radio nodes, respectively, to the source and to the target. Subsequently, we set up transmission channels shared by these nodes, maintaining that they do not interfere with each other. To monitor the effect of increased numbers of wireless nodes on the architecture, a set of configuration models, Ti, has been implemented, each generating a single communication flow between the source and the target. Noteworthy, also, is that each data stream is routed via an ad-hoc communication channel, a critically useful alternative in our study to monitor wireless communication in Delta MINs networks. The successive steps, necessary to transmit data between switch and radio-hub are displayed in Figure 6. A radio node is connected with the switch through its wired gate. The information passing among radio nodes is accomplished via radio channels in which flow control is managed through a token implemented on the medium access control unit (MAC). A radio hub can route data using several communication channels. Connection is maintained by means of a token ring algorithm. Thus, a radio node can exchange informa  
Figure 5: Wired and Wireless Communication on Delta MIN. tion through the channel's related token ring. Obviously, a radio node must capture the token to reactivate a transmission through a specific communication channel. After that, three traffic model patterns (Hot-spot, Fixed, and Random) are selected to assess the efficiency performance of the envisioned communication scheme. Each of these scenarios would be applied in accordance with various Network configurations (Table 2). Our main motivation behind opting for these parameters lies in ensuring the truthiness of values, as already integrated and explored in several previously published research works. The network size denotes the number of cores liable to generate traffic to activate the computation processing. For each Network configuration, a Mesh of switch nodes is needed to implement the MIN communication architecture. Figure 7 displays the average delay measurements reached on matching several network sizes and traffic patterns generated by following four wireless configuration profiles (\(T1\), \(T2\), \(T3\), \(T5\)). As a first stage of the analysis, the effect of increasing the number of radio-hubs for a defined traffic configuration is evaluated.