Several power allocation algorithms for cooperative relay networks are presented in the literature. These contributions assume perfect channel knowledge and capacity achieving codes. However in practice, obtaining the channel state information at a relay or at the destination is an estimation problem and can generally not be error free. The investigation of the power allocation mechanism in a w...

in the new production systems, finding a way to improving the product and system reliability in design is a very important. the reliability of the products and systems may improve using different methods. one of this methods is redundancy allocation problem. in this problem by adding redundant component to sub-systems under some constraints, the reliability improved. in this paper we worked on ...

In millimeter wave (mmWave) systems, energy is a scarce resource due to the large channel losses and high energy usage by analog-to-digital converters. To mitigate this issue, we propose an integrated architecture that combines the sub-6 GHz and mmWave technologies. We investigate the power and bandwidth allocation jointly across the interfaces in order to maximize the achievable sum rate under...

An adaptive transmission scheme, in which the work in [3] is extended to multiuser environment, is proposed for LDPC-coded MIMO-OFDMA cellular systems that employ FDD by considering active user selection and sub-channel power allocation. The performance of the proposed scheme is obtained from simulation and compared with that of the conventional scheme using mean SNR only. It is shown that the ...

A channel allocation algorithm includes a channel acquisition and a channel selection scheme. Most of the previous work concentrates on the channel selection algorithm since early channel acquisition algorithms are centralized and rely on a MSS to accomplish channel acquisition. The centralized schemes are neither scalable nor reliable. Recently, distributed dynamic channel allocation algorithm...

In this paper, we study the physical layer security (PLS) problem in the dual hop orthogonal frequency division multiplexing (OFDM) based wireless communication system. First we consider a single user single relay system and study a joint power optimization problem at the source and relay subject to individual power constraint at the two nodes. The aim is to maximize the end to end secrecy rate...

This paper proposes a fuzzy channel allocation controller (FCAC) for hierarchical cellular systems. The FCAC mainly contains a fuzzy channel allocation processor (FCAP) which is designed to be in a two-layer architecture that consists of a fuzzy admission threshold estimator in the first layer and a fuzzy channel allocator in the second layer. The FCAP chooses the handoff failure probability, d...

The study investigated the allocation of transmission power and bits for a point-to-point orthogonal frequency-division multiplexing channel assuming perfect channel information at the receiver, but imperfect channel information at the transmitter. Channel information was quantized at the receiver and was sent back to the transmitter via a finite-rate feedback channel. Based on limited feedback...