Design and Implementation of a Highly Efficient Quasi-Cyclic Low-Density Parity-Check Transceiving System Using an Overlapping Decoder.

The traditional LDPC encoding and decoding system is characterized by low throughput and high resource consumption, making it unsuitable for use in cost-efficient, energy-saving sensor networks. Aiming to optimize coding complexity and throughput, this paper proposes a combined design of a novel LDPC code structure and the corresponding overlapping decoding strategies. With regard to structure of LDPC code, a CCSDS-like quasi-cyclic parity check matrix (PCM) with uniform distribution of submatrices is constructed to maximize overlap depth and adapt the parallel decoding. In terms of reception decoding strategies, we use a modified 2-bit Min-Sum algorithm (MSA) that achieves a coding gain of 5 dB at a bit error rate of 10-6 compared to an uncoded BPSK, further mitigating resource consumption, and which only incurs a slight loss compared to the standard MSA. Moreover, a shift-register-based memory scheduling strategy is presented to fully utilize the quasi-cyclic characteristic and shorten the read/write latency. With proper overlap scheduling, the time consumption can be reduced by one third per iteration compared to the non-overlap algorithm. Simulation and implementation results demonstrate that our decoder can achieve a throughput up to 7.76 Gbps at a frequency of 156.25 MHz operating eight iterations, with a two-thirds resource consumption saving.

Comparative studies on multi-carrier transmission schemes in mountainous and dense forest environment.

Earthquakes, forest fires, mudslides and other natural disasters occur frequently in recent years. They usually occur in the mountainous and dense forests, where local communication facilities do not exist or have been destroyed by the disasters. Adverse geographical environment poses a huge challenge to emergency communications and rescue. This paper presents comparative studies on multi-carrier transmission schemes in the mountainous and dense forest environment. The comprehensive communication performance for various multi-carrier waveform schemes, has been extensively analyzed by using the Stanford University Interim channel model. Simulation results show that the pruned discrete Fourier transform spread filter bank multi-carrier scheme exhibits generally the best performance in terms of transmission rate and distance for most operation modes.

Millimeter-Wave Multi-Channel Backscatter Communication and Ranging with an FMCW Radar.

A multi-channel backscatter communication and radar sensing system is proposed and demonstrated in this paper. Frequency modulated continuous wave (FMCW) radar ranging is integrated with simultaneous uplink data transmission from a self-packaged active radio frequency (RF) tag. A novel package solution is proposed for the RF tag. With the proposed package, the RF tag can transmit a 32-QAM signal up to 2.5 Gbps and QPSK signal up to 8 Gbps. For a multi-tag scenario, we proposed using spread spectrum code to separate the data from each tag. In this case, tags can be placed at arbitrary locations without adjacent channel interference. Proof-of-concept simulations and measurements are demonstrated. A 625 Mbps data rate is achieved in a dual-tag scenario for two tags.

Bayesian Device-Free Localization and Tracking in a Binary RF Sensor Network.

Received-signal-strength-based (RSS-based) device-free localization (DFL) is a promising technique since it is able to localize the person without attaching any electronic device. This technology requires measuring the RSS of all links in the network constituted by several radio frequency (RF) sensors. It is an energy-intensive task, especially when the RF sensors work in traditional work mode, in which the sensors directly send raw RSS measurements of all links to a base station (BS). The traditional work mode is unfavorable for the power constrained RF sensors because the amount of data delivery increases dramatically as the number of sensors grows. In this paper, we propose a binary work mode in which RF sensors send the link states instead of raw RSS measurements to the BS, which remarkably reduces the amount of data delivery. Moreover, we develop two localization methods for the binary work mode which corresponds to stationary and moving target, respectively. The first localization method is formulated based on grid-based maximum likelihood (GML), which is able to achieve global optimum with low online computational complexity. The second localization method, however, uses particle filter (PF) to track the target when constant snapshots of link stats are available. Real experiments in two different kinds of environments were conducted to evaluate the proposed methods. Experimental results show that the localization and tracking performance under the binary work mode is comparable to the those in traditional work mode while the energy efficiency improves considerably.

Co-Delivery of Docetaxel and Berbamine by Chitosan/Sulfobutylether-ß-Cyclodextrin Nanoparticles for Enhancing Bioavailability and Anticancer Activities.

Novel dual-drug sulfobutylether-ß-cyclodextrin (CD)/chitosan (CS) nanoparticles (NPs) containing docetaxel (DTX) and berbamine were developed and evaluated in this study. These NPs were prepared using ionic gelation method and were characterised for their particle size, polydispersity, zeta potential, drug loading percentage and yield. Cytotoxicity was measured through 3-(4,5-dimethyltiazol-2-ly)-2,5-diphenyltetrazolium bromide assay, and the expression of survivin mRNA in MCF-7 cells was detected using qRT-PCR. Cellular uptake and apoptosis were also analysed. Compared with the other DTX formulations in this study, the dual-drug CD/CS NPs showed better release and intestinal transport profiles in vitro and had improved pharmacokinetics data. The dual-drug CD/CS NPs exhibited higher cytotoxicity, cellular uptake, apoptosis and inhibition with the survivin mRNA expression. The relatively improved oral bioavailability and better antitumour efficacy indicated that the dual-drug CD/CS NPs developed in our study possessed significant advantages and might be a promising strategy for the development of drug, delivery systems for cancer chemotherapy.

Co-administration with cell penetrating peptide enhances the oral bioavailability of docetaxel-loaded nanoparticles.

This study proposes a novel docetaxel (DTX) cyclodextrin inclusion-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (D-CNPs) system with cell penetrating peptide (CPP), and evaluates its potential for oral administration of DTX. Heptaarginine (R7) was used as the CPP. D-CNPs were prepared by the double-emulsification method. The mean particle size and zeta potential of the resulting D-CNPs were 198.7 ± 12.56 nm and -27.25 ± 4.62 mV, respectively, and their mean encapsulation efficiency and drug loading were 80.35 ± 6.37% and 1.02 ± 0.15%, respectively. The morphology of the D-CNPs was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The release behavior of the D-CNPs was studied by using the dialysis method. The relative bioavailability of D-CNPs and D-CNPs co-administered with R7 was enhanced about 5.57- and 9.43-fold, respectively, compared with the free DTX suspension. Furthermore, D-CNPs with R7 displayed maximum cytotoxicity against MCF-7 cells in MTT assay. D-CNPs co-administered with R7 showed markedly higher fluorescence intensity than D-CNPs without CPP. The results suggest that the D-CNPs co-administered with R7 could be a potential delivery system with excellent therapeutic efficacy for targeting the drugs to cancer cells.