FDMA Enabled Phase-based Wireless Network-on-Chip using Graphene-based THz-band Antennas

The future growth in System-on-chip design is moving in the direction of multicore systems. Design of efficient interconnects between cores are crucial for improving the performance of a multicore processor. Such trends are seen due to the benefits the multicore systems provide in terms of power reduction and scalability. Network-on-chips (NoC) are viewed as an emerging solution in the design of interconnects in multicore systems. However, Traditional Network-on-chip architectures are no longer able to satisfy the performance requirements due to long distance communication over multi-hop wireline paths. Multi-hop communication leads to higher energy consumption, increase in latency and reduction in bandwidth. Research in recent years has explored emerging technologies such as 3D integration, photonic and radio frequency based Network-on-chips. The use of wireless interconnects using mm-wave antennas are able to alleviate the performance issues in a wireline interconnect system. However, to satisfy the increasing demand for higher bandwidth and lower energy consumption, Wireless Network-on-Chip enabled with high speed direct links operating in THz band between distant cores is desired. Recent research has brought to light highly efficient graphene-based antennas operating in THz band. These antennas can provide high data rate and are found to consume less power with low area overheads. In this thesis, an innovative approach using novel devices based on graphene structures is proposed to provide a high-performance on-chip interconnection. This novel approach combines the regular NoC structure with the proposed wireless infrastructure to exploit the performance benefits. An architecture with wireless interfaces on every core is explored in this work. Simultaneous multiple communications in a network can be achieved by adopting Frequency Division Multiple access (FDMA). However, in a system where all cores are equipped with a wireless interface, FDMA requires more number of frequency bands. This becomes difficult to achieve as the system scales and the number of cores increase. Therefore, a FDMA protocol along with a 4-phased repetitive multi-band architecture is envisioned in this work. The phase-based protocol allows multiple wireless links to be active at a time, the phase-based protocol along with the FDMA protocol provides a reliable data transfer between cores with lesser number of frequency bands. In this thesis, an architecture with a combination of FDMA and phase-based protocol using point-to-point graphene-based wireless links is proposed. The proposed architecture is also extended for a multichip system. With cycle accurate system-level simulations, it is shown that the proposed architecture provides huge gains in performance and energy-efficiency in data transfer both in NoC based multicore and multichip systems