Analysis, design and performance evaluation of on-chip optical wireless links

In Network-on-Chips (NoCs), Optical Wireless (OW) interconnects have recently gained attention to overcome the limitations of existing wired and wireless Radio Frequency (RF) technologies, while preserving bandwidth and delay characteristics of optical interconnects. In this paper, we investigate the communication performance of the on-chip OW links by considering the effects of both wireless propagation and interlink interference, which arises when the same optical frequency is used for multiple transmissions in a NoC. A Ray Tracing (RT) approach is applied to the layered structure of the onchip wireless channel to obtain accurate modeling of multipath propagation. By using the RT results, the Bit Error Probability (BEP) is evaluated as a function of desired and interfering signal powers, which depend on the far-field spatial fading conditions. The physical parameters and the geometry of the scenario, and the impact of antenna radiation pattern are taken into account in the evaluation. The analysis and the results enable system designers to design and provide efficient on-chip interconnects, optimizing not only the topology of the OW links in the NoC, but also the physical parameters of the links, including antenna characteristics, that influence the wireless communication.