We overview a digital duplex scheme called Zipper, intended for DMT-based VDSL systems. The Zipper multicarrier duplex scheme represents a breakthrough toward digital implementation of frequency-division duplexing. A duplex scheme is a method to divide the capacity of a line between the upstream and downstream directions. Zipper divides the available bandwidth by assigning different subcarriers...

In this paper, we consider user selection and downlink precoding for an over-loaded single-cell massive multiple-input multiple-output (MIMO) system in frequency division duplexing (FDD) mode, where the base station is equipped with a dual-polarized uniform planar array (DP-UPA) serves large number of single-antenna users. Due to absence uplink-downlink channel reciprocity high-dimensionality m...

This paper studies the channel asymmetric characteristic between a downlink and an uplink channel in orthogonal frequency division multiple access (OFDMA)/ time division duplexing (TDD) systems. To investigate the downlink and uplink channel asymmetry, we derive a propagation loss mo-del and a shadowing model taking into consideration geometrical information and inter-cell interference. Then, t...

The ever-increasing needs for more spectrum resources, and the emerging new Radio Access Technologies under the 5G umbrella add to the complexity of the Spectrum Toolbox in mobile networks landscape. This article covers 3GPP LTE evolution from Release 8 up to the Release 14, which deals with the LTE-Advanced Pro enhancements. A collection of available frequency bands, spectrum aggregation mecha...

Full-duplex (FD) wireless -simultaneous transmission and reception at the same frequency -is an emerging wireless duplexing scheme that has the potential to significantly improve wireless network performance [1-2]. However, the biggest challenge associated with FD wireless is the tremendous amount of self-interference (SI) on top of the desired signal. The SI has to be suppressed below the rece...

In this paper, we propose, implement and analyze an Authenticated Encryption with Associated Data Scheme (AEADS) based on the Modified Duplex Construction (MDC) that contains a chaotic compression function (CCF) our neural network revised (CNNR). Unlike standard duplex construction (SDC), in MDC there are two phases: initialization phase duplexing phase, each contain CNNR formed by single layer...

A new multiuser detector (MUD) exploiting the MAP algorithm is proposed for channels affected by severe multipath and is then suitable for Time-Division Duplexing (TDD) CDMA receivers. After coherent combining the received multipaths, a multidimensional MAP nonlinearity is employed to compute step-by-step the A Posteriori Probabilities (APPs) of the transmitted data for each user separately and...

This work concerns wireless cellular networks applying time division duplexing (TDD) massive multiple-input multiple-output (MIMO) technology. Such systems suffer from pilot contamination during channel estimation, due to the shortage of orthogonal pilot sequences. This paper presents a solution based on pilot sequence hopping, which provides a randomization of the pilot contamination. It is sh...

Wireless energy transfer technology enables tiny electronic devices in the Internet of Things to harvest energy from radio frequency signals. Radio frequency signals also have been used to carry information in the area of wireless communications for more than one century. Therefore, it is feasible to simultaneously transfer information and energy, from a dual functional access point, to wireles...