In this work, we compare different pre-coding techniques and their performance in a cellular MIMO OFDM downlink. The first target is to determine the achievable additional beamforming gain by using a near-optium pre-coder instead of DFT-based pre-coding. In the second step, we include multi-user selection diversity, which turned out to be advantageous especially for downlink cooperation. An ext...

This paper considers the problem of designing utility maximization scheduling algorithms for multi-channel(e.g, OFDM-based) wireless down-link systems. We extend Lyapunov Optimization to design a throughput-utility maximizing algorithm that uses a queue-based and delay-based Lyapunov functions, where the delay uses explicit delay information from the head-of-line packet destined to each user. O...

For Wireless Personal Area Network (WPAN) systems, resource allocation between several users within a piconet and the coexistence of several piconets are very important points to take into consideration for the optimization of high data rate Ultra Wide Band (UWB) systems. To improve the performance of the Multi Band OFDM (Orthogonal Frequency Division Multiplex) solution proposed by the Multi B...

---------------------------------------------------------------------***----------------------------------------------------------------Abstract –Orthogonal Frequency Division Multiplexing (OFDM)is the promising candidate of a multiple carrier modulation technique because it does not require equalizers. OFDM is robust in adverse channel conditions and allows a high level of spectral efficiency....

Unmanned aerial vehicle (UAV)-based communication system design has already attracted substantial interest due to UAV flexibility in deployment, cost effectiveness, and in-built line-of-sight air-to-ground channels. However, there is a persistent issue of security threats associated with the broadcast nature UAV: physical layer (PLS) can be introduced enhance secrecy performance that regard. In...

High-resolution fully digital transceivers are infeasible at millimeter-wave (mmWave) due to their increased power consumption, cost, and hardware complexity. The use of low-resolution converters is one possible solution realize architectures mmWave. In this paper, we consider a setting in which base station with constant envelope quantized (CEQ) digital-to-analog on each radio frequency chain ...

The 5G system-based cognitive radio network is promised to meet the requirements of huge data applications with spectrum. However, M-ary effect on detection has not been thoroughly investigated. In this paper, an quadrature amplitude modulation system studied. Many rates are used in study 4, 16, 64, and 256 constellation points. applied cooperative spectrum sensing enhance performance for vario...

In this work, we propose intrinsic interference mitigating coordinated beamforming (IIM-CBF)-based transmission strategies for the downlink of multi-user multiple-input-multiple-out (MIMO) systems and coordinated multi-point (CoMP) systems where filter bank based multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) is employed. Our goal is to alleviate the dimensionality constr...

Conventional Multi-User Detection (MUD) algorithms for the Multi-Input, Multi-Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system fail to consider the detection performance and algorithm complexity simultaneously. To address this problem, a new Joint Intelligent MUD (JI-MUD) algorithm that aims to improve the MUD performance of the MIMO-OFDM system and to reduce the complexity ...

The noncoherent capacity of multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is first derived. Then, an adaptive bit-interleaved coded modulation (BICM) scheme for the MIMO-OFDM system that exploits transmitter beamforming and variable-rate-variablepower (VRVP) QAM is proposed to enhance the throughput in a time-varying environment. The throughput of the v...