查看更多>>摘要：This paper investigates and compares three channel models for the fifth generation(5G)wire-less communications:the quasi deterministic radio chan-nel generator(QuaDRiGa),the NYUSIM channel simu-lator model developed by New York University,and the more general 5G(MG5G)channel model.First,the char-acteristics of the modeling processes of the three models are introduced from the perspective of model framework.Then,the small-scale parameter modeling strategies of the three models are compared from space/time/frequency domains as well as polarization aspect.In particular,the drifting of small-scale parameters is introduced in detail.Finally,through the simulation results of angular power spectrum,Doppler power spectrum density,temporal autocorrelation function,power delay profile,frequency correlation function,channel capacity,and eigenvalue dis-tribution,the three models are comprehensively investig-ated.According to the simulation results,we clearly ana-lyze the impact of the modeling strategy on the three channel models and give certain evaluations and sugges-tion which lay a solid foundation for link and system-level simulations for 5G transmission algorithms.
查看更多>>摘要：This paper presents a low power con-sumption and low cost electrically erasable program-mable read-only memory(EEPROM)for radio frequency identification(RFID)tag chip.A read-write circuit with parallel input and serial output is proposed.Only one sensitive amplifier is used to read the data in memory,which can effectively reduce the power consumption of the read operation.Because the tag may be read or writ-ten while moving,the internal voltage may change in a wide range.Therefore,this paper designs a charge pump and its control circuit with wide voltage working range.The proposed EEPROM is integrated into an RFID tag chip and fabricated using a 180 nm complementary met-al-oxide semiconductor(CMOS)process.Experimental results show that the circuit can work in the input voltage range of 1 V to 1.8 V,and the minimum current of read operation and write operation is 0.68 μA and 30 μA respectively,which has the characteristic of low power consumption.
查看更多>>摘要：Radio frequency(RF)devices used in modern wireless systems must meet increasingly complic-ated spectral constraints while still operating with high power efficiency.A fast real-time two-tone active load-pull algorithm is proposed to assess the relationship between nonlinear performance with associated device load impedance variations.This algorithm employs real time measurement data to extract two-tone local nonlin-ear behaviour model,which is further used for the predic-tion of injected signal value in the active real-time load-pull system,therefore minimizing the number of itera-tions required for load emulation.The proposed method was validated on a real two-tone load-pull measurement bench using off-the-shelf instruments.The result shows that the measurement speed has been greatly increased without sacrifice of the impedance emulation accuracy.This intelligent two-tone load-pull algorithm is expected to be applied in the designing of modern communication system and radar transmitters,as well as the validation of the models of radio frequency transistors.
查看更多>>摘要：This paper reports a successive approx-imation register(SAR)analog-to-digital converters(ADCs)with the 2nd-order and optimized noise shaping(NS)scheme.Based on the feed-forward structure,both noise transfer function(NTF)zero and pole optimization have been achieved simultaneously utilizing a cascaded IIR-FIR(infinite impulse response and finite impulse re-sponse)filter.The analysis shows that the proposed struc-ture provides a better NS efficiency than prior arts.The efficiency of the proposed NS scheme and the ADC per-formance are verified by simulation achieving a 14.2 ef-fective number of bits with an 8-bit SAR ADC architec-ture at an over sampling rate of 8 sampled at 100 MS/s.Taking advantage of the NTF zero-pole optimization,a low resolution SAR ADC is allowed under the same quantization noise budget in this structure.
查看更多>>摘要：As solid-state drives(SSD)have been widely adopted,secure data deletion becomes an essential component for ensuring user privacy,preventing sensit-ive data leakage.Due to the erase-before-write property,erasure operation and scrub operation substituting for overwriting technologies are proposed to meet the re-quirements.However,both methods bring the severe page-copying issue,declining read/write performance,and shortening the lifetime of SSD.In this paper,this issue is alleviated by reserving pages at the page allocation stage to mitigate program disturbance and increasing program step voltage during reprogramming operation to reduce the reprogram latency.The proposed scheme is evaluated by a series of experiments;the results show that the pro-posed scheme could achieve significant deletion time re-duction and alleviate page-copying overhead.
查看更多>>摘要：This paper presents a clock-less pro-grammable pre-emphasis technique realized by a driver with combined resistive-inductive-capacitive source degen-eration for high-speed serial link transmitters.The addi-tion of a series inductive-capacitive resonance network ex-pands the bandwidth of the driver without lowering down the pre-emphasis gain.The driver with the proposed pre-emphasis technique provides adjustable gain from mid-fre-quency to high-frequency which is controlled by a tun-able tail current,offering the capability for the transmit-ter to adapt to different cable loss from 0 to 6 dB.The driver has been employed in a 2:4 multiplexing and cable driving integrated circuit for 1.65 Gbps high-definition-multimedia-interface and digital-visual-interface applica-tion to drive up to 7 m 24-American-wire-gauge cable.Fabricated in 180 nm SiGe BiCMOS technology,the transmitter consumes 68.6 mW for 6 dB pre-emphasis un-der 3.3 V power supply.
查看更多>>摘要：With the development of face image syn-thesis and generation technology based on generative ad-versarial networks(GANs),it has become a research hot-spot to determine whether a given face image is natural or generated.However,the generalization capability of the existing algorithms is still to be improved.Therefore,this paper proposes a general algorithm.To do so,firstly,the learning on important local areas,containing many face key-points,is strengthened by combining the global and local features.Secondly,metric learning based on the ArcFace loss is applied to extract common and discrimin-ative features.Finally,the extracted features are fed into the classification module to detect GAN-generated faces.The experiments are conducted on two publicly available natural datasets(CelebA and FFHQ)and seven GAN-generated datasets.Experimental results demonstrate that the proposed algorithm achieves a better generalization performance with an average detection accuracy over 0.99 than the state-of-the-art algorithms.Moreover,the pro-posed algorithm is robust against additional attacks,such as Gaussian blur,and Gaussian noise addition.
查看更多>>摘要：Since differential fault analysis(DFA)was first implemented on data encryption standard(DES),many scholars have improved this attack and ex-tended the limit of the original last two rounds to the earlier rounds.However,the performance of the novel at-tacks which target middle rounds is not effective,i.e.the number of correct/incorrect ciphertexts required is very large and the recovered result maybe not correct.We ad-dress this problem by presenting new DFA methods that can break 3DES when injecting faults at round 12 or 13.By simulating the process of single-bit error propagation,we have built two kinds of error propagation models as well as an intermediate error propagation state table.Then we simplify the intermediate states into state tem-plates that will be further used to locate the injected fault position,which is the main difficulty of implementing fault injection in the middle rounds.Finally,in terms of the idea of error propagation and probability theory,we can recover the last round key only using 2 sets of cor-rect/incorrect ciphertexts when inducting fault in the 13th round and 4 sets of correct/incorrect ciphertexts when inducting fault in the 12th round.
查看更多>>摘要：The increasing commercialization and massive deployment of radio frequency identification(RFID)systems has raised many security related issues which in return evokes the need of security protocols.Lo-gic of events theory(LoET)is a formal method for con-structing and reasoning about distributed systems and protocols that involve concepts of security.We propose fresh ciphertext and ciphertext release lemmas to extend LoET for analyzing and proving the security of authentic-ation protocols that use symmetric key cryptography more than just digital signature.Based on the extended LoET we formally analyze and prove the authentication property of RCIA protocol,which provides mutual au-thentication between Tag and Reader in RFID system.Our proof approach based on extended LoET could be ap-plied to the design and analysis of such ultralightweight RFID mutual authentication protocols.
查看更多>>摘要：GIFT is a lightweight block cipher with an substitution-permutation-network(SPN)structure proposed in CHES 2017.It has two different versions whose block sizes are 64 and 128 respectively.In RSA 2019,Zhu et al.found some differential characteristics of GIFT with mixed integer linear programming(MILP)method and presented corresponding differential attacks.In this paper,we further find some linear characteristics with MILP method.For GIFT-64,we find two 11-round linear characteristics with correlation 2-29,and use one of them to present a 16-round linear attack on GIFT-64 by adding 4 rounds before and one round after the linear character-istic.For GIFT-128,we find a 16-round linear character-istic with correlation 2-62.As far as we know,it is the longest linear characteristic found for GIFT-128.Using the 16-round linear characteristic,we present a 20-round linear attack on GIFT-128 by adding 2 rounds before and 2 rounds after the linear characteristic.
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