13 research outputs found
A SIMPLE BEAMFORMING DESIGN FOR SECURE IN MIMO SWIPT SYSTEM
This paper investigates the beamforming design for secure transmission in multiple-input multiple-output (MIMO) communication systems with simultaneous wireless information and power transfer (SWIPT), where the energy harvesting (EH) receivers may eavesdrop the confidential information send to the information decode (ID) receiver. To solve the non-convex problem, we propose a simple solution, which is to chose a beamforming matrix part first, then find the rest of the beamforming matrix by solving the convex problem. Finally, numerical results are provided to validate our proposed algorithm
Secure Information Flow for IoT Applications
This paper discusses how to ensure security, i.e., confidentiality and integrity properties, for data in IoT applications. While confidentiality could be assessed via information flow analysis, integrity is ensured by error-correcting codes. In addition to errors, many communication channels also cause erasures, i.e., the demodulator cannot decide which symbol the received waveform represents. The paper proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory storage as well as decoding complexity
Interference Analysis for OFDM Transmissions in the Presence of Time-Varying Channel Impairments
This paper is concerned with the detrimental effect of phase noise on the performance of orthogonal frequency division multiplexing (OFDM) transmissions over time-selective channels. In the literature, most of the existing papers analyze the performance of OFDM systems in the presence of either time-selective channels or phase noise. Unlike the existing studies, this paper formulates an approximate expression of signal-to-interference-plus-noise ratio (SINR) at an OFDM receiver in the presence of both phase noise and time-selective channel response. The formulated SINR expression can be used as a guideline in determining appropriate OFDM transmission settings under a given quality-of-service (QoS) requirement. To illustrate the tightness of the approximate SINR formulation, empirical and theoretical values of SINR under different OFDM system settings are presented in this paper
Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial
Background
Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population.
Methods
AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921.
Findings
Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months.
Interpretation
Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke
A Beamforming Algorithm for MIMO SWIPT Systems
Efficient usage of energy resources is a growing concern in today’s communication systems. Energy harvesting is a new paradigm and allows the nodes to recharge their batteries from the environment. In this paper, we focus on the design of optimal linear beamformer for multi- input multi-output (MIMO) simultaneous wireless information and power transfer (SWIPT) system. We formulate the problem of maximizing the information rate while keeping the energy harvested at the energy receivers above given levels. Finally, simulation results demonstrate the efficiency of the proposed algorithm
MMSE Beamforming Design for IoT MIMO SWIPT System
Internet of Things (IoT) is a smart infrastructure of the unique identification device capable of wireless communication with each other, and human services on a large scale through the Internet. The IoT devices themselves must self-aware and harvest the energy they need from ambient sources. Simultaneous wireless information and power transfer (SWIPT) is a promising new solution to provide an opportunity for energy-restrained wireless devices to operate uninterruptedly. In this paper, we propose a beamforming approach for Internet of Things (IoT) multi-input multi-output (MIMO) SWIPT downlink systems, which minimizes the mean square error (MSE) of the information decode (ID) device while satisfying the energy constraint of the energy harvesting (EH) device. Simulation results are provided to evaluate the performance and confirm the efficiency of the proposed algorithm
Secure Information Flow for IoT Applications
This paper discusses how to ensure security, i.e., confidentiality and integrity properties, for data in IoT applications. While confidentiality could be assessed via information flow analysis, integrity is ensured by error-correcting codes. In addition to errors, many communication channels also cause erasures, i.e., the demodulator cannot decide which symbol the received waveform represents. The paper proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory storage as well as decoding complexity
A MMSE-based Beamforming Algorithm for MIMO Point-to-Point Full-Duplex Communication Systems
In this paper, we focus on the precoding design for sum rate maximization while considering the effects of residual SI for point – to-point multiple input/multiple output (MIMO) Full-Duplex systems. The MMSE-based beamforming algorithm was proposed to cancel the SI. The results shown that, the self-interference cancellation is done by matrix precoding at the transmitter if the total number of transmitting antenna of two nodes is greater than the number of receiving antenna of one node. The Bit Error Rate (BER) was also evaluated in the simulation
On The Performance of MIMO AF Full-Duplex Joint Antenna and Relay Selection Network
This paper investigates a multi-input multi-output (MIMO) multi-relay amplify-and-forward (AF) full-duplex (FD) network using optimal joint relay and antenna selection over Rayleigh block fading channels. For system performance analysis, outage probability (OP) is theoretically analyzed to obtain exact and asymptotic expressions of OP where asymptotic derivations using the assumption of high signal-to-noise rate (SNR) regime. Numerical results are provided to verify the validity of the derived OP expressions by comparing with the related empirical performance. The paper shows that under different scenarios the exact OP expression values are close the related empirical ones while the approximated OP expression values approach to the empirical OP under high SNR conditions