MAC Design in Pulse-Based Communication Systems

ABSTRACT Pulse-based communication systems are a promising candidate in the deployment of future wireless networks, thanks to the potential robustness and capacity guaranteed by the transmission of pulses of very short duration. In the framework of pulse-based communication systems, the Impulse Radio-Ultra Wide Band (IR-UWB) technique recently received particular attention. In the past, most of the UWB research focused on hardware and physical layer aspects in order to solve the technological challenges posed by IR-UWB. UWB peculiar characteristics may, however, also stimulate innovative higher layers' design. This work addresses Medium Access Control (MAC) issues for IR-UWB communication systems and extends the discussion to wireless optical communication systems. Typical characteristics of an IR-UWB system are presented, and solutions proposed for such systems at the MAC layer are reviewed. The applicability of such solutions to an optical wireless communications system is then discussed, highlighting analogies and differences between IR-UWB and wireless optical systems

MAC-Oriented Programmable Terahertz PHY via Graphene-based Yagi-Uda Antennas

Graphene is enabling a plethora of applications in a wide range of fields due to its unique electrical, mechanical, and optical properties. In the realm of wireless communications, graphene shows great promise for the implementation of miniaturized and tunable antennas in the terahertz band. These unique advantages open the door to new reconfigurable antenna structures which, in turn, enable novel communication protocols at different levels of the stack. This paper explores both aspects by, first, presenting a terahertz Yagi-Uda-like antenna concept that achieves reconfiguration both in frequency and beam direction simultaneously. Then, a programmable antenna controller design is proposed to expose the reconfigurability to the PHY and MAC layers, and several examples of its applicability are given. The performance and cost of the proposed scheme is evaluated through full-wave simulations and comparative analysis, demonstrating reconfigurability at nanosecond granularity with overheads below 0.02 mm$^{2}$ and 0.2 mW.Comment: Accepted for presentation in IEEE WCNC '1