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''s 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.

Meeting Name

20th IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems (2005: Oct. 3-5, Monterey, CA)


Electrical and Computer Engineering

Keywords and Phrases

QCA Cell Structures; QCA Designs; QCA-Based Majority Gate Design; QCA-Based System Design; Adders; Carry Look-Ahead Adder; Cellular Automata; Circuit Reliability; Clocks; Effect-Induced Fault Tolerance; Fault Diagnosis; Fault Tolerance; Flexible Clocking Schemes; Logic Design; Quantum Computing; Quantum Gates; Quantum Mechanics Complexity; Single Clock-Controlled Majority Gates

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2005 IEEE Computer Society, All rights reserved.

Publication Date

01 Oct 2005