We propose an efficient open-loop channel estimator for a millimeter-wave (mm-wave) hybrid multiple-input multiple-output (MIMO) system consisting of radio-frequency (RF) beamformers with large antenna arrays followed by baseband MIMO processor. A sparse signal recovery problem exploiting the nature mm-wave channels is formulated estimation based on parametric model quantized angles departures/arrivals (AoDs/AoAs), called angle grids. The solved orthogonal matching pursuit (OMP) algorithm...

Hybrid multiple input output (MIMO) systems consist of an analog beamformer with large antenna arrays followed by a digital MIMO processor. Channel estimation for hybrid in millimeter wave (mm-wave) communications is challenging because the array and low signal-to-noise ratio (SNR) before beamforming. In this paper, we propose open-loop channel estimator mm-wave exploiting sparse nature channels. A signal recovery problem formulated solved orthogonal matching pursuit (OMP) based methods....

We deal with a cost-based adaptive handover hysteresis scheme for the horizontal decision strategies, as one of self-optimization techniques that can minimize failure rate (HFR) in 3rd generation partnership project (3GPP) long-term evolution (LTE) system based on network-controlled hard handover. Especially, real-time operation, we propose an simplified cost function considering some dominant factors closely related to HFR performance such load difference between target and serving cells,...

This paper proposes a technique that jointly estimates the I/Q mismatch, dc offset, carrier frequency and channel for receivers in selective channels. The joint estimator is data-aided requires training sequence derived based on maximum likelihood (ML) criterion. characteristics of are analyzed. In particular, it shown its accuracy almost achieves Crame/spl acute/r-Rao lower bound (CRLB). advantage proposed over an existing method demonstrated through computer simulation.

We consider the design of a uniform circular array (UCA) system under misalignment over line-of-sight (LoS) channels. UCAs have been considered as useful structures since their LoS channels can be diagonalized without channel state information at transmitter (Tx). However, such characteristic holds only when transceiver arrays are perfectly aligned. To overcome this difficulty, we propose an optimal method and architectures for UCA systems that achieve capacity knowledge angles. end, first...

A digital signal processing (DSP) technique is presented that can compensate for the in-phase/quadrature-phase (I/Q) mismatch in low-intermediate frequency (IF) receivers. In particular, a non-data-aided (NDA) I/Q estimator derived by exploiting statistical independence between desired and image signals. The proposed obtains two baseband signals (uncompensated signals) from IF processes them to estimate mismatch. mean-square error (MSE) of analyzed. Computer simulation results indicate...

We consider the problem of time domain (TD) channel estimation for wideband millimeter wave systems with a hybrid architecture. TD estimators can exploit both angular and delay sparsity, perform better than frequency (FD) exploiting only sparsity; however, former usually require heavier computational load latter. To overcome this difficulty, we propose an efficient, two-step estimator: in first step, effective incorporated beamforming, array responses, pulse shaping is estimated by least...

This paper compares the uniform circular array based orbital angular momentum (UCA-OAM) scheme, which enables spatial multiplexing transmission of data symbols via multiple OAM modes, with UCA-MIMO scheme through numerical analysis and simulation in terms spectral efficiency feedback over-head. Specifically, on relations between eigenmodes UCA-SVD-MIMO system modes UCA-OAM as well capacity formula, channel capacities two systems are compared for cases where equal power allocation...

A digital-signal-processing technique is presented that can compensate for the frequency-independent inphase/quadrature (I/Q) mismatch and dc offset in zero-intermediate-frequency direct-conversion receivers. The proposed compensator consists of I/Q estimators followed by a canceller self-image suppressor. are nondata-aided (NDA) schemes derived assuming desired signal random variable having an arbitrary circular symmetric distribution. Cramer-Rao lower bounds (CRLBs) NDA estimation derived,...

Packet scheduler plays the central role in determining overall performance of 3GPP long-term evolution (LTE) based on packet-switching operation. In this paper, a novel minimum transmit power-based (MP) packet-scheduling algorithm is proposed that can achieve power-efficient transmission to UEs while providing both system throughput gain and fairness improvement. The new scheduling metric focusing ratio power per bit allocates physical resource block (PRB) UE requires least bit. Through...

We consider channel estimation for massive multiple-input multiple-output (MIMO) systems operating in frequency division duplexing (FDD) mode. By exploiting the sparsity of significant propagation paths MIMO channels, we develop a compressed sensing (CS) based estimator that can reduce pilot overhead as compared with conventional least squares (LS) and minimum mean square error (MMSE) estimators. The proposed scheme is on oblique matching pursuit (ObMP), an extension orthogonal (OMP),...

A time-and-frequency hybrid multiplexing technique for a multiple-input multiple-output (MIMO) orthogonal frequency-division (OFDM) radar is proposed. Discrete Fourier transform (DFT)-coded OFDM waveforms are introduced, which allow it to be free from range-dependent angle errors. These readily used provide both time-domain and frequency-domain multiplexings in the MIMO radar. The DFT-coded shortens maximum unambiguous range, while lowers Doppler ambiguity. of domain techniques can mitigate...

This letter presents a calibration technique for uniform circular array orbital angular momentum systems that can estimate and compensate gain/phase mismatch among radio-frequency (RF) chains in the transmitter receiver simultaneously. The basic idea is RF chain parameters be estimated from mathematical model of channel estimates when ideal matrix known priori. It shown maximum-likelihood (ML) estimation error becomes zero-mean complex Gaussian random variable, then, joint ML solution derived.

This paper presents an adaptive digital signal processing technique that cancels self-image interference due to frequency-independent, in-phase/quadrature-phase (I/Q) mismatch in zero-intermediate frequency (IF) direct-conversion receivers. The proposed technique, which is referred as the normalized least-mean square cancellation (NLMS-ASIC) algorithm, ASIC controls filter weight minimize power of output using NLMS type weight-control mechanism. Some closed-form equations are derived for...

Cooperative multiple input output (MIMO) system is capable in mitigating co-channel interference (CCI) that limits the downlink capacity of cellular network. Among joint transmission designs for base station (BS) cooperation, linear transmissions with per-base power constraint preferred due to its computational simplicity and reality. However, since sometimes make BSs cannot fully utilize their usable power, it leads considerable loss. In this paper, we propose a BS selection technique MMSE...

We propose the use of uniform circular array subarrays (UCA-SAs) for millimeter wave (MMW) communication systems over line sight (LoS) channels and design beamforming coefficients each subarray. Specifically, a UCA-SA consisting N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> subarrays, which are M × square arrays, designed so that effective channel becomes circulant. To this end, we first show can be decomposed into <sup...

This paper investigates the problem of MAI (multiple access interference) occurrence when timing misalignment occurs in downlink channel OFDM-based networks. The adaptive guard band allocation scheme is mainly designed to achieve synchronization while reducing carrier redundancy and maintaining high throughput asynchronous Thus, proposed reduces effect for users receiving multiple transmission signals from surrounding BSs (Base Stations). In a simulation, it noteworthy that this very...

This paper presents a novel technique for estimating the path loss parameters of radio channels using monostatic radar. To this end, two-way model scenario radar sub-terahertz (sub-THz) band channel measurement is expressed as function parameter one-way model, and then are estimated maximum-likelihood estimation algorithm based on linear regression models, which single reference distance dual distances. verify effectiveness proposed method, experiment conducted in an indoor environment...

In this paper, we deal with user scheduling algorithms for a codebook based precoding of multiuser multiple-input multiple-output (MIMO) downlink system considered in IEEE 802.16m and 3rd Generation Partnership Project Long-Term Evolution (3GPP LTE) standardization. We especially focus on per-user unitary rate control (PU2RC) semi-orthogonal selection schemes. Also, examine the disadvantage these schemes - loss sum-capacity when size is larger than number total users who request...

This paper presents a multi-mode transmission technique that can increase the T-R distance of UCA OAM systems. The proposed uses dual polarized antennas to number simultaneously transmitable modes at specific T- R by exploiting two basis dipole antenna elements, and further extends reaching signals using inter-mode spreading between belonging same polarization domain. Simulation results show scheme improves distances least 2 times as much conventional in transmitting with symbol error rate,...

This paper introduces a hard handover strategy with novel adaptive hysteresis adjustment that is needed to reduce drop rate in 3GPP long term evolution (LTE). First of all, we adopt Hybrid scheme considering both the received signal strength (RSS) and load information adjacent evolved Node Bs (eNBs) as factor for deciding target eNB. The causes status between eNBs be largely similar. Then, propose modified load-based find suitable value utilizing feature small difference serving obtained...

An ICI (Inter-Cell Interference) mitigation algorithm for exploiting macroscopic diversity an up-link OFDMA (Orthogonal Frequency Division Multiple Access) system is proposed. To reduce the influence of carrier collision, order resource allocation coordinated based on location each MS (Mobile Station) and associated group. This consideration significantly reduces enhances throughput at boundary region.

This paper presents the achievable capacity expressions with analytical closed forms of spatial multiplexing transmission (SMT) and single antenna (SAT) for multicell downlink distributed systems (DAS). Considering that SMT SAT yield high gains center edge cell, respectively, we also propose switching algorithms depending on a user location. The scheme decides favorable technique between through instantaneous or ergodic comparison. Simulation results show well match to empirical expressions....

A digital signal processing (DSP) technique is presented that can compensate for the I/Q mismatch in low-IF receivers. In particular, a non-data-aided (NDA) estimator derived by exploiting statistical independence between desired and image signals. The mean square error (MSE) of estimate analyzed. Computer simulation results indicate proposed outperform existing adaptive DSP techniques are based on use blind separation algorithms. It observed rejection ratio (IRR) decreases monotonically...