Networks-on-Chip (NoCs) are currently the paradigm of choice to interconnect the cores of a chip multiprocessor. However, conventional NoCs may not suffice to fulfill the on-chip communication requirements of processors with hundreds or thousands of cores. The main reason is that the performance of such networks drops as the number of cores grows, especially in the presence of multicast and broadcast traffic. This not only limits the scalability of current multiprocessor architectures, but also sets a performance wall that prevents the development of architectures that generate moderate-to-high levels of multicast. In this paper, a Wireless Network-on-Chip (WNoC) where all cores share a single broadband channel is presented. Such design is conceived to provide low latency and ordered delivery for multicast/broadcast traffic, in an attempt to complement a wireline NoC that will transport the rest of communication flows. To assess the feasibility of this approach, the network performance of WNoC is analyzed as a function of the system size and the channel capacity, and then compared to that of wireline NoCs with embedded multicast support. Based on this evaluation, preliminary results on the potential performance of the proposed hybrid scheme are provided, together with guidelines for the design of MAC protocols for WNoC.

Graphene is enabling a plethora of applications in a wide range of fields due to its unique electrical, mechanical, and optical properties. Among them, graphene-based plasmonic miniaturized antennas (or shortly named, graphennas) are garnering growing interest in the field of communications. In light of their reduced size, in the micrometric range, and an expected radiation frequency of a few terahertz, graphennas offer means for the implementation of ultra-short-range wireless communications. Motivated by their high radiation frequency and potentially wideband nature, this paper presents a methodology for the time-domain characterization and evaluation of graphennas. The proposed framework is highly vertical, as it aims to build a bridge between technological aspects, antenna design, and communications. Using this approach, qualitative and quantitative analyses of a particular case of graphenna are carried out as a function of two critical design parameters, namely, chemical potential and carrier mobility. The results are then compared to the performance of equivalent metallic antennas. Finally, the suitability of graphennas for ultra-short-range communications is briefly discussed.

Graphene is a promising material which has been proposed to build graphene plasmonic miniaturized antennas, or graphennas, which show excellent conditions for the propagation of Surface Plasmon Polariton (SPP) waves in the terahertz band. Due to their small size of just a few micrometers, graphennas allow the implementation of wireless communications among nanosystems, leading to a novel paradigm known as Graphene-enabled Wireless Communications (GWC). In this paper, an analytical framework is developed to evaluate how the channel capacity of a GWC system scales as its dimensions shrink. In particular, we study how the unique propagation of SPP waves in graphennas will impact the channel capacity. Next, we further compare these results with respect to the case when metallic antennas are used, in which these plasmonic effects do not appear. In addition, asymptotic expressions for the channel capacity are derived in the limit when the system dimensions tend to zero. In this scenario, necessary conditions to ensure the feasibility of GWC networks are found. Finally, using these conditions, new guidelines are derived to explore the scalability of various parameters, such as transmission range and transmitted power. These results may be helpful for designers of future GWC systems and networks.

Networks-on-chip (NoCs) are emerging as the way to interconnect the processing cores and the memory within a chip multiprocessor. As recent years have seen a significant increase in the number of cores per chip, it is crucial to guarantee the scalability of NoCs in order to avoid communication to become the next performance bottleneck in multicore processors. Among other alternatives, the concept of wireless network-on-chip (WNoC) has been proposed, wherein on-chip antennas would provide native broadcast capabilities leading to enhanced network performance. Since energy consumption and chip area are the two primary constraints, this work is aimed to explore the area and energy implications of scaling a WNoC in terms of: 1) the number of cores within the chip, and 2) the capacity of each link in the network. To this end, an integral design space exploration is performed, covering implementation aspects (area and energy), communication aspects (link capacity), and network-level considerations (number of cores and network architecture). The study is entirely based upon analytical models, which will allow to benchmark the WNoC scalability against a baseline NoC. Eventually, this investigation will provide qualitative and quantitative guidelines for the design of future transceivers for wireless on-chip communication.

We present a new 16-QAM near complementary sequence construction where the length of the sequences is n = 2m. The 16-QAM near complementary sequences are constructed by nonlinear offsets. But the peak-to-mean envelope power ratio bounds for these 16-QAM near complementary sequences is as low as 2.4. The number of newly constructed 16-QAM near complementary sequences is ([(m!)/2])4m+1.

We present a new 16-QAM near complementary sequence construction where the length of the sequences is n = 2m. The number of newly constructed 16-QAM near complementary sequences is (m!/2)4m+1, and the PMEPR bounds for newly constructed 16-QAM near complementary sequences is 2.4.

In this correspondence, we present a new construction for 64-QAM Golay sequences of length n=2/sup m/ for integer m. The peak envelope power (PEP) of 64-QAM Golay sequences is shown to be bounded by 4.66n. The new construction of 64-QAM Golay sequences of length n=2/sup m/ is based on our earlier construction of new offsets of 16-QAM Golay sequences which are also presented here. The total number of offsets of 64-QAM Golay sequences is 496 for m=2,808 for m=3 and 976 for m=4, obtained by computer search. We also computed the PEP distribution for 64-QAM Golay sequences for m=2, m=3, and m=4.