Efficient and Robust Delay-Insensitive QCA (Quantum-Dot Cellular Automata) Design

The concept of clocking for QCA, referred to as the four-phase clocking, is widely used. However, inherited characteristics of QCA, such as the way to hold state, the way to synchronize data flows, and the way to power QCA cells, make the design of QCA circuits quite different from VLSI and introduce a variety of new design challenges. The most severe challenges are due to the fact that the overall timing of a QCA circuit is mainly dependent upon its layout. This issue is commonly referred to as the layout =timing problem. To circumvent the problem, a novel self-timed circuit design technique referred to as the locally synchronous, globally asynchronous design for QCA has been recently proposed. The proposed technique can significantly reduce the layout-timing dependency from the global network of QCA devices in a circuit; therefore, considerably flexible QCA circuit design is be possible. Also, the proposed technique is more scalable in designing large-scale systems. Since a less number of cells is used, the overall area is smaller and the manufacturability is better. In this paper, numerous multi-bit adder designs are considered to demonstrate the layout efficiency and robustness of the proposed globally asynchronous QCA design techniqu

QCA-Based Majority Gate Design under Radius of Effect-Induced Faults

This paper presents reliable QCA cell structures for designing single clock-controlled majority gates with a tolerance to radius of effect-induced faults, for use as a basic building component for carry look-ahead adder. Realizable quantum computing is still well in the future due to the complexity of the quantum mechanics that govern them. In this regard, QCA-based system design is a challenging task since each cell\u27\u27s state must interact with all the cells that are in its energy-effective range in its clocking zone, referred to as its radius of effect. This paper proposes a design approach for majority gates to overcome the constraints imposed by the radius of effect of each cell with respect to clock controls. Radius of effect induces faults that lead to constraints on the clocking scheme of majority gates. We show majority gate structures that operate with multiple radius of effect-induced faults under a single clock control. The proposed design approach to a single clock controlled majority gate ultimately facilitate more efficient and flexible clocking schemes for complex QCA designs

Designing Layout-Timing Independent Quantum-Dot Cellular Automata (QCA) Circuits by Global Asynchrony

The concept of clocking for QCA, referred to as the four-phase clocking, is widely used. However, inherited characteristics of QCA, such as the way to hold state, the way to synchronize data flows, and the way to power QCA cells, make the design of QCA circuits quite different from VLSI and introduce a variety of new design challenges and the most severe challenges are due to the fact that the overall timing of a QCA circuit is mainly dependent upon its layout. This fact is commonly referred to as the layout = timing problem. to circumvent the problem, a novel self-timed QCA circuit design methodology referred to as the Globally Asynchronous, Locally Synchronous (GALS) Design for QCA is proposed in this paper. the proposed technique can significantly reduce the layout-timing dependency from the global network of QCA devices in a circuit; therefore, considerably flexible QCA circuit design and floorplanning will be possible

A Management of Highway Emergency Vehicle-to-Vehicle Communication

This paper presents a new protocol and algorithms to manage vehicle emergency situation on highway. The focus is given on how to detect false alarm messages from the vehicles that are not in an effective radius from the accident of concern. This problem is investigated by using a new technique, referred to as Location Counter on Neighborhood Table. The technique facilitates the process of keeping track of the location of other vehicles in an effective radius on top of the vehicle-to-vehicle communication protocol. The cost for the Neighborhood Table is maintained low in a matter of the number of vehicles in the effective radius; and the algorithms by using the Location Counter is kept simple in order to effectively manage emergency highway situations in timely manner. An example is provided to demonstrate the efficiency and effectiveness