%0 Journal Article
%T Reversible Logic-Based Fault-Tolerant Nanocircuits in QCA
%A Bibhash Sen
%A Siddhant Ganeriwal
%A Biplab K. Sikdar
%J ISRN Electronics
%D 2013
%R 10.1155/2013/850267
%X Parity-preserving reversible circuits are gaining importance for the development of fault-tolerant systems in nanotechnology. On the other hand, Quantum-dot Cellular Automata (QCA), a potential alternative to CMOS, promises efficient digital design at nanoscale. This work targets design of reversible ALU (arithmetic logic unit) in QCA (Quantum-dot Cellular Automata) framework. The design is based on the fault tolerant reversible adders (FTRA) introduced in this paper. The proposed fault tolerant adder is a parity-preserving gate, and QCA implementation of FTRA achieved 47.38% fault-free output in the presence of all possible single missing/additional cell defects. The proposed designs are verified and evaluated over the existing ALU designs and found to be more efficient in terms of design complexity and quantum cost. 1. Introduction Reversible logic has attractive perspective of constructing digital devices that can realize computing unit with almost zero power dissipation. Landauer [1] proved that for irreversible computations, each bit of information loss generates joules of heat energy. The energy required for a binary transition is given by SNL (Shannon-Von Neumann-Landauer) expression in [1] as follows: where is Boltzmann constant and £¿K. This is the minimum energy to process a bit. Bennett [2] showed that a zero power dissipation in logic circuit is possible only if the circuit is composed of reversible logic gates. Since QCA circuits are clocked information preserving systems, the energy dissipation of QCA circuits can be significantly lower than . This feature favours the introduction of QCA technology in reversible logic design. Though, reversibility recovers bit loss, but it is not able to detect bit error in circuit. Fault-tolerant reversible circuits are capable of preventing errors at outputs. If the system itself made of fault-tolerant components, then the detection and correction of faults become easier and simple. In communication and many other systems, fault tolerance is achieved by parity. Therefore, parity-preserving reversible circuits will be the future design trends to the development of fault-tolerant reversible systems in nanotechnology. On the other hand, QCA (Quantum-dot Cellular Auto-mata) is considered to be promising in the field of nanotechnology due to their extremely small sizes and ultralow-power consumption [3]. The QCA is based on encoding binary information in the charge configuration of quantum-dot cells. The interaction between cells is coulombic and provides the necessary computing power. The fundamental unit of
%U http://www.hindawi.com/journals/isrn.electronics/2013/850267/