Transmission Efficiency Loss Research Articles

The AI-Based Channel Prediction Scheme for the 5G Wireless System in High-Speed V2I Scenarios

Now, the fifth-generation (5G) system plays a more and more important role in the high-speed vehicle-to-infrastructure (V2I) scenario. In order to realize the high-reliability and high-efficiency transmission, it is essential to obtain accurate channel state information (CSI) for the 5G system. However, due to the fast time-varying and nonstationary characteristics of the channel in high-speed V2I scenarios, channel estimation is a challenging issue. In this paper, an artificial intelligence- (AI-) based channel prediction scheme, called AI-ChannelNet, is proposed to improve the CSI prediction performance in high-speed V2I scenarios. Specifically, AI-ChannelNet is trained in real time based on the historical channel estimation on the reference signal (RS) to realize accurate channel prediction and then recovers the received signal according to the predicted channel information. The integration of the convolutional neural network (CNN) and long short-term memory (LSTM) is designed to extract temporal features of the channel. And an online RS-based training algorithm is proposed, enabling AI-ChannelNet to track the channel variation. Evaluated by experiments, the proposed scheme outperforms conventional methods a lot, and more improvement could be achieved at a higher speed. Besides, the proposed scheme performs well without modification of the 5G radio frame and loss of transmission efficiency.

First Report of a Mastrevirus (Geminiviridae) Transmitted by the Corn Leafhopper.

Maize striate mosaic virus (MSMV; genus Mastrevirus) was recently reported in maize plants in Brazil and also detected by metagenomic analyses in the corn leafhopper, Dalbulus maidis (DeLong & Wolcott). Although these findings suggested that D. maidis is a potential vector, no transmission studies have been performed. Here, we tested the transmission of MSMV by D. maidis from field-collected infected plants and plants infected with MSMV via leafhopper-mediated transmission in the laboratory; all plants were confirmed positive for MSMV by PCR. In each one of three transmission replicates, aviruliferous D. maidis nymphs and adults were confined together on a source plant during a 4-day acquisition access period (AAP) and subsequently transferred to healthy maize seedlings (10 individuals per test plant) in a series of 4-day inoculation access periods (IAPs). We also tested transmission by the corn aphid, Rhopalosiphum maidis (Fitch) and by mechanical inoculation of healthy maize seedlings. Only D. maidis transmitted MSMV, with overall transmission rates of 29.4 and 39.5% on field-collected infected plants and 18.5% on infected plants in laboratory. D. maidis transmitted MSMV until the third (8 to 12 days after the AAP) or fourth successive IAP (12 to 16 days), with gradual loss in transmission efficiency and rate of viruliferous insects over time, suggesting a persistent but nonpropagative mode of transmission. Infected test plants showed mottling symptoms with mild chlorotic streaks and height reduction. This is the first report of transmission of a mastrevirus by D. maidis, facilitating the completion of Koch's postulate for MSMV.

A mosquito feeding assay to examine Plasmodium transmission to mosquitoes using small blood volumes in 3D printed nano-feeders

BackgroundTo understand the dynamics of malaria transmission, membrane feeding assays with glass feeders are used to assess the transmission potential of malaria infected individuals to mosquitoes. However, in some circumstances, use of these assays is hindered by both the blood volume requirement and the availability of fragile, specially crafted glass feeders. 3D printed plastic feeders that require very small volumes of blood would thus expand the utility of membrane feeding assays.MethodsUsing two 3D printing production methods, MultiJet (MJ) and Digital Light Processing (DLP), we developed a plastic version of the most commonly used standard glass feeder (the mini-feeder) with an improved design, and also a smaller feeder requiring only 60 µl of blood (the nano-feeder). Performance of the 3D printed feeders was compared to standard glass mini-feeders by assessing infectivity of gametocytes to mosquitoes in standard membrane feeding assays with laboratory reared Anopheles stephensi mosquitoes and cultured Plasmodium falciparum gametocytes. In addition, the optimum number of mosquitoes that can feed on the nano-feeder was determined by evaluating fully fed mosquitoes visually and by assessing blood- meal volume with a colorimetric haemoglobin assay.ResultsThe 3D printing methods allowed quick and inexpensive production of durable feeders. Infectivity of gametocytes to mosquitoes was comparable for MJ and DLP 3D printed feeders and glass feeders, and the performance of the 3D printed feeders was not influenced by repeated washing with bleach. There was no loss in transmission efficiency when the feeder size was reduced from mini-feeder to nano-feeder, and blood-meal volume assessment indicated ~10 An. stephensi mosquitoes can take a full blood-meal (median volume 3.44 µl) on a nano-feeder.ConclusionsHere we present 3D printed mini- and nano-feeders with comparable performance to the currently used glass mini-feeders. These feeders do not require specialized glass craftsmanship, making them easily accessible. Moreover, the smaller nano-feeders will enable evaluation of smaller blood volumes that can be collected from finger prick, thus expanding the utility of membrane feeding assays and facilitating a more thorough evaluation of the human infectious reservoir for malaria.

Polarization-Tracking-Free IFoF Mobile Fronthaul With Adaptively Modulated PDM Multiband DDO-OFDM

This letter proposes a polarization-tracking-free polarization division multiplexing (PDM) in an intermediate frequency over fiber mobile fronthaul system based on multiband direct detection optical orthogonal frequency division multiplexing (DDO-OFDM) with adaptive modulation. The use of two orthogonally polarized optical carriers with a simple optical filter at each radio access unit is sufficient to perform passive demultiplexing of the corresponding multiband signals in PDM schemes without transmission efficiency loss in training signal, which is commonly found in conventional PDM demultiplexing schemes. We experimentally achieved a multiband OFDM signal with adaptive modulation, which maximizes signal capacity, in a PDM scheme with the data rate of 49.64 Gb/s, which doubles that of corresponding single polarization schemes, over a 25-km single mode fiber. We also achieved a 6-dB power margin which is sufficient for the wireless transmission part.

Performance analysis of complexity reduction BP decoding of rateless codes by deleting low reliable symbols

This paper investigates the performance of the method used to reduce the decoding complexity of rateless codes through the deletion of the received symbols with low reliability. In the decoder, the received symbols whose absolute value of logarithm likelihood ratio (LLR) is lower than the threshold are removed, together with their corresponding edges, and thus not involved in the decoding process. The relationship between the deletion probability and the likelihood ratio deletion threshold is derived. The average mutual information per received symbol is analyzed in the case of deletion. The required number of symbols for the decoder to keep the same performance as regular decoding decreases since the average mutual information per symbol increases with the deletion, thus reducing the decoding complexity. This paper analyzes the reduction of decoding computations and the consequent transmission efficiency loss from the perspective of mutual information. The simulation results of decoding performance are consistent with those of the theoretical analysis, which show that the method can effectively reduce the decoding complexity at the cost of a slight loss of transmission efficiency.

Torradoviruses are transmitted in a semi-persistent and stylet-borne manner by three whitefly vectors

Members of the genus Torradovirus (family Secoviridae, type species Tomato torrado virus, ToTV) are spherical plant viruses transmitted by the whitefly species Trialeurodes vaporariorum and Bemisia tabaci. Knowledge on the mode of vector transmission is lacking for torradoviruses. Here, the mode of transmission was determined for Tomato marchitez virus (ToMarV). A minimal acquisition access period (AAP) and inoculation access period (IAP) of approximately 2h each was required for its transmission by T. vaporariorum, while optimal transmission required an AAP and IAP of at least 16h and 8h, respectively. Whiteflies could retain the virus under non-feeding conditions for at least 8h without loss of transmission efficiency, but upon feeding on a non-host plant in between the AAP and IAP they retained the virus for no more than 8h. Similar conditions supported transmission of isolates of ToTV and Tomato chocolàte virus (ToChV) by T. vaporariorum and B. tabaci. Additionally, similar experiments revealed the banded-winged whitefly (Trialeurodes abutilonea) as a vector for all three virus species. The results are congruent with acquisition and retention periods for semi-persistent virus transmission. RT-PCR detection analysis of ToTV and ToMarV in the vector's body revealed their presence in the stylet, but not in the head where the pharynx of the foregut is located. The results altogether indicate a semi-persistent stylet-borne mode of vector transmission for torradoviruses. Additionally, this is the first group of spherical viruses transmitted by at least three different species of whiteflies.

Two-way relaying using constant envelope modulation and phase-superposition-phase-forward

In this article, we propose the idea of phase-superposition-phase-forward (PSPF) relaying for 2-way 3-phase cooperative network involving constant envelope modulation with discriminator detection in a time-selective Rayleigh fading environment. A semi-analytical expression for the bit-error-rate (BER) of this system is derived and the results are verified by simulation. It was found that, compared to one-way relaying, 2-way relaying with PSPF suffers only a moderate loss in energy efficiency (of 1.5 dB). On the other hand, PSPF improves the transmission efficiency by 33%. Furthermore, we believe that the loss in transmission efficiency can be reduced if power is allocated to the different nodes in this cooperative network in an 'optimal' fashion. To further put the performance of the proposed PSPF scheme into perspective, we compare it against a phase-combining phase-forward technique that is based on decode-and-forward (DF) and multi-level CPFSK re-modulation at the relay. It was found that DF has a higher BER than PSPF and requires additional processing at the relay. It can thus be concluded that the proposed PSPF technique is indeed the preferred way to maintain constant envelope signaling throughout the signaling chain in a 2-way 3 phase relaying system.

BER Performance Analysis of MC-CDMA with Overlap-FDE

Recently, multi-carrier code division multiple access (MC-CDMA) has been attracting much attention as a broadband wireless access technique for the next generation mobile communication systems. Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can take advantage of the channel frequency-selectivity and improve the average bit error rate (BER) performance due to frequency-diversity gain. The conventional FDE requires the insertion of the guard interval (GI) to avoid the inter-block interference (IBI), resulting in the transmission efficiency loss. In this paper, an overlap FDE technique, which requires no GI insertion, is presented for MC-CDMA transmission. An expression for the conditional BER is derived for the given set of channel gains. The average BER performance in a frequency-selective Rayleigh fading channel is evaluated by Monte-Carlo numerical computation method using the derived conditional BER and is confirmed by computer simulation of the signal transmission.

Inductively coupled plasma mass spectrometry, coincidence laser spectroscopy (ICP-MS-CLS), simulation of the transmission efficiency of a 3D quadrupole ion trap for cooling energetic ions from the ICP prior to optical detection

A fundamental requirement of ICP-MS-CLS is a post mass separation ion beam with an energy spread of less than ∼0.2 eV to enable efficient pumping of fluorescent lines with a narrow band (Δν ∼ 100 kHz) laser for the optical detection step. The role of a 3D quadrupole ion trap for ion beam cooling, as an accessory for a new generation of ICP-MS-CLS (inductively coupled plasma mass spectrometry, coincidence laser spectroscopy) (B. L. Sharp, P. S. Goodall, L. M. Ignjatovic and H. Teng, J. Anal. At. Spectrom., 2007, 22, 1447) instrument, was investigated by means of numerical simulation. Whereas in-trap ion cooling is well established, it was found that extraction of cooled ions from the trap introduced additional broadening and a loss of transmission efficiency. Modelling was based on a beam of 20 eV mean energy with a spread of 3 eV which represents a worst case scenario for the ions derived from an ICP source. The efficiency of the cooling process (trapping + extraction), as well as the energy distributions of ions exiting the trap, were calculated and compared for several methods of extraction. Trapping efficiencies of ∼25% were obtained at buffer gas pressures up to 10 mTorr. The addition of virtual reflectrons to the trap resulted in an improvement in the energy distribution of the trapped ions by lowering the wings of the distribution, but did not significantly improve the efficiency. Zero field, rf field only, quadrupolar field and homogeneous field ion extraction were investigated to recover ions from the trap, and of these quadrupolar extraction was best. However, extraction efficiency and ion energy distribution were inversely related so that quadrupolar extraction at Uq = 10 V yielded an exit ion energy distribution of 0.5 eV half width, compared with a trapped width of 0.03 eV, but with only 10% transmission efficiency. Thus, it was demonstrated that a 3D trap can be used to cool energetic ions for post-trap mass or spectroscopic examination, but the low efficiency makes it unsuitable for use with ICP-MS-CLS.

Modeling cascading failures in the North American power grid

The North American power grid is one of the most complex technological networks, and its interconnectivity allows both for long-distance power transmission and for the propagation of disturbances. We model the power grid using its actual topology and plausible assumptions about the load and overload of transmission substations. Our results indicate that the loss of a single substation can result in up to $25\%$ loss of transmission efficiency by triggering an overload cascade in the network. The actual transmission loss depends on the overload tolerance of the network and the connectivity of the failed substation. We systematically study the damage inflicted by the loss of single nodes, and find three universal behaviors, suggesting that $40\%$ of the transmission substations lead to cascading failures when disrupted. While the loss of a single node can inflict substantial damage, subsequent removals have only incremental effects, in agreement with the topological resilience to less than $1\%$ node loss.

Autocorrelation and SNR for the Output of a Square-Law Device and Low-Pass Filter With Square-Law SSB Plus Gaussian Noise at the Input

Powers' square-law single-sideband (SSB) signal is shown to be to ordinary SSB roughly what amplitude modulation (AM) with carrier is to amplitude-modulation suppressed carrier (AMSC) signaling. That is, both SSB and AMSC require coherent demodulation at the receiver to recover the information signal properly and this requires the slaving of the receiver to the transmitter or at least the use of expensive phase-locking circuitry. A carrier is added to the AMSC signal to make possible inexpensive incoherent demodulation at the receiver (envelope detection) and the resulting transmission inefficiency and loss of SNR in the receiver are accepted to achieve this simple detection. In the same manner, Powers' square-law SSB allows inexpensive incoherent demodulation at a loss in transmission efficiency and receiver SNR. This loss in SNR is found to always be within 3 dB of that in AM envelope detection for large SNR when equal input-signal power and noise spectraldensity levels are assumed. Further, there are situations for which the SNR performance is better than AM envelope detection (i.e., 100 percent tone modulation is one such case). The main difference is that AM with carrier and AMSC require twice the transmission bandwidth of SSB or Powers' square-law SSB.

Improvements in the transmission of a tandem accelerator

First order calculations are given which were carried out to obtain a good optical matching of a polarized ion source to the 12 MeV H.V.E.C. tandem Van de Graaff of the Utrecht State University. Two alternative injection systems are compared with one another and a relative transmission figure is given. The influence of higher order effects may be diminished by relatively simple means. The ion injection energy may be decreased considerably without significant loss in transmission efficiency if this is required for constructional reasons.

Short-term probing behavior of Myzus persicae (Sulzer) as affected by fasting, anesthesia, and labial manipulation

An analysis was made of the probing behavior of Myzus persicae (Sulzer) during a 5-minute access period on yellow mustard seedlings, Brassica campestris L. Aphids anesthetized with carbon dioxide, with or without subsequent manual manipulation of the labium to expose the tips of the stylets, probed less frequently and effected fewer transmissions of cabbage mosaic virus than did unanesthetized aphids. Aphids that were fasted for 5 minutes after an acquisition probe also gave fewer transmissions, but this reduction was not associated with changes in probing behavior when compared to untreated insects. The lowest rate of transmission was by aphids which had been anesthetized and then manually manipulated to expose the tip of their stylets. But since the probing behavior of manipulated aphids was very similar to that of anesthetized ones, behavior alone could not explain the additional loss in transmission efficiency. In this work neither the duration of the intervals between probes, nor the duration of the probes themselves, appeared to be strongly associated with the variations in transmission that occurred in response to the various treatments.

The Effect of Wing Movement by the Green Peach Aphid on the Transmission of Lettuce Mosaic Virus

Investigations were conducted to determine if wing movement of alate green peach aphids, Myzus Persicae (Sulzer), would affect transmission efficiency of lettuce mosaic virus when compared with transmission efficiency of alates not allowed wing movement and apterous adults. All aphids tested were attached to pins with watercolor paint. Single aphids were used in 30 tests with each of the 3 groups. Treatment times used for the groups were 0, 15,30, 60, 900, 1800, and 2,700 seconds. Preceding treatment, all aphids were given a 15-second artificially interrupted access feeding on a lettuce mosaic virus source plant. The results indicated that regardless of form, transmission efficiency was similar at any time period. Loss of transmission efficiency was similar for all groups.