Abstract

Increasing demands of wearable health monitoring seek dedicated spectrum for short range wireless communication of biosignals, for which frequency band near 400 MHz has been utilized recently. While using the dedicated spectrum, biosignal communication must not cause any out of band radiations and interference, for which there is a strong need to develop spur- free, low phase noise and energy efficient wireless transmitters (TX). In this research, for the first time we present design and implementation of a reference-spur-free, low phase noise, sub-mW dual modulation mode (frequency shift keying (FSK) and on-off keying (OOK)) 400 MHz TX for wearable health monitoring, where RF synthesis depends solely on an extremely low phase noise oscillator, which uses a 400 MHz surface acoustic wave resonator and does not include any power hungry, spur- generating frequency multiplier or phase/frequency lock loop. The proposed TX has been designed and fabricated in 180 nm CMOS technology. Measurement results show that the energy efficiencies of the proposed TX in FSK and OOK mode are 1.8 nJ/bit at 250 kb/s and 0.23 nJ/bit at 2 Mb/s, respectively. To prove the utility of the proposed TX, biosignal communication is also demonstrated with the help of a commercial receiver in actual operating scenarios, where the measured bit error rate in FSK mode was < 10−5 for range of 2 m. Index Terms—Health-monitoring, wearable, spur-free, trans- mitter, FSK, OOK, 400 MHz, MedRadio

Abstract

This paper discusses the phenomena of proteresis, commonly known as inverse hysteresis, and the various methods to implement it. Proteresis generates an advanced response when compared to hysteresis, which improves the system's speed, maintaining the noise immunity intact. This feature of proteresis is seen in multiple naturally occurring phenomena. The paper implements proteresis in domains of electronics and optics, keeping in view essential constraints like area, power, throughput, and speed. The electronic domain consists of two models, one using CMOS circuits and the other using discrete components. The transistor-level design of a proteretic device is on 180 nm CMOS technology, and proof of concept is demonstrated using post-layout simulations. This design is operated on a supply voltage of 1.8 V and consumes significantly less power of 633 µW at a moderate frequency of 10 MHz. The …

Abstract

This article explores the feasibility of utilizing an interdigitated capacitor (IDC) based RF sensor for studying nanoparticle properties. The parameters include their size, shape, thickness, and relative arrangement in aqueous media. The analysis is carried out using the CAD tool high frequency structure simulator (HFSS). We study the variation in properties of spherical, cubical, disc-shaped, and polyhedral gold nanoparticles. The change in the resonance frequency, resonance amplitude, and − 3 dB bandwidth is analyzed for each case. The findings show that the change in the IDC-based RF sensor’s resonance characteristics can be used to track the variations in morphology and arrangements of gold nanoparticles.

Abstract

This paper reports solvent based optimization of radio frequency (RF) sensors for detecting ethanol mixtures in petrol using complementary split ring resonators (CSRR). The optimization is carried out using binary particle swarm optimization (BPSO) in presence of mask by placing the sample under test (SUT) above the highly sensitive CSRR region. The motivation behind this work has been to detect miniscule changes of ethanol in the dielectric constant of the petrol. The RF sensors designed using BPSO enables faster convergence providing more efficient designs offering enhanced sensitivity at a normalized frequency of 2.66% and 1.81% when compared to 1.02% of conventional CSRR as presented in the simulation results. Index Terms

Abstract

This paper demonstrates radio frequency (RF) sens- ing of saccharides such as glucose, fructose and sucrose based on Complementary Split Ring Resonator (CSRR). The CSRR based planar sensor is designed and fabricated over FR4 substrate of thickness 1.6 mm and with copper on both sides of thickness 0.035 mm. The fabricated sensor is connected to the Vector Network Analyzer (VNA) to study the electromagnetic interac- tions behavior between the designed sensor and saccharides. The quantitative and qualitative analysis is conducted by changing the concentration of saccharides in aqueous solution from 10 mg/ml to 50 mg/ml in steps of 10 mg/ml and then by changing the overall sample volume from 1 μl to 100 μl in variable step sizes. The resonant frequency property is utilized for detecting small changes in saccharides concentration of up to 10 mg/ml and overall sample volume change of 1 μl. The proposed RF sensor is highly robust, reliable, cost-effective and easy to use over other existing methodologies. Index Terms—Radio Frequency, Mic

Abstract

We have analyzed the thermal blooming effect on laser beam propagation under atmospheric turbulence in different environments. It is observed that the laser source having an input power of less than 4 kW is less affected by thermal blooming and more appropriate for incoherent beam combinations in any environmental conditions.

Abstract

Product codes are a class of codes which have generator matrices as the tensor product of the component codes and the codeword itself can be represented as an (m × n) array, where the component codes themselves are referred to as the row and column codes. Maximally recoverable product codes (MRPCs) are a class of codes which can recover from all information theoretically recoverable erasure patterns, given the a column and b row constraints imposed by the code. In this work, we derive puncturing and shortening properties of maximally recoverable product codes. We give a sufficient condition to characterize a certain subclass of erasure patterns as correctable and another necessary condition to characterize another subclass of erasure patterns as not correctable. In an earlier work, higher order MDS codes denoted by MDS(l) have been defined in terms of generic matrices and these codes have been shown to be constituent row codes for maximally recoverable product codes for the case of a = 1. We derive a certain inclusion-exclusion type principle for characterizing the dimension of intersection spaces of generic matrices. Applying this, we formally derive a relation between MDS(3) codes and points/lines of the associated projective space.

Abstract

In distributed storage systems, cooperative regener- ating codes tradeoff storage for repair bandwidth in the case of multiple node failures. In rack-aware distributed storage systems, there is no cost associated with transferring symbols within a rack. Hence, the repair bandwidth will only take into account cross-rack transfer. Rack-aware regenerating codes for the case of single node failures have been studied and their repair bandwidth tradeoff characterized. In this paper, we consider the frame- work of rack-aware cooperative regenerating codes for the case of multiple node failures where the node failures are uniformly distributed among a certain number of racks. We characterize the storage repair-bandwidth tradeoff as well as derive the minimum storage and minimum repair bandwidth points of the tradeoff. We also provide explicit constructions of minimum bandwidth rack-aware cooperative regenerating codes and minimum storage rack-aware cooperative regenerating codes for a large range of parameters. We also consider another extension of minimum stor- age cooperative regenerating codes, in which we design slightly sub-optimal cooperative regenerating codes with much lower sub- packetization. -MSR codes are a class of codes introduced to tradeoff sub-packetization level for a slight increase in the repair bandwidth for the case of single node failures. We introduce the framework of -MSCR codes which allow for a similar tradeoff for the case of multiple node failures. We present a construction of -MSCR codes, which can recover from two node failures, by concatenating a class of MSCR codes and scalar linear codes. We give a repair procedure to repair the -MSCR codes in the event of two node failures and calculate the repair bandwidth for the same. We characterize the increase in repair bandwidth incurred by the method in comparison with the optimal repair bandwidth. Finally, we show the subpacketization level of -MSCR codes scales logarithmically in the number of nodes.

Abstract

Reed-Solomon codes are polynomial evaluation codes and it has been shown that these can be efficiently repaired in the case of single node failures by considering the code symbols as vectors over a subfield and the helper nodes transfer multiple symbols over the subfield for repair. Tamo-Barg codes are a class of optimal LRCs which are also polynomial evaluation codes. These codes have Reed-Solomon codes as their local codes. In the case of single node failures, the repair takes place only within the local groups. In this paper, we address the question of whether the repair bandwidth within the local group can be further reduced by using the technique of Reed-Solomon repair. We give a construction based on cosets where the scheme requires lesser repair bandwidth than naive Reed-Solomon repair. We also give another construction based on optimal Reed-Solomon codes which achieve the cutset bound, where the Tamo-Barg codes are designed such that the local Reed-Solomon codes can be optimally repaired. We make the connection between these class of codes and the codes with local regeneration.

Abstract

The unmanned aerial vehicle (UAV) based communication is expected to play an important role in enabling a variety of applications in future cellular networks. However, because of the mobility of the UAVs, the communications links involving UAVs undergo large-scale temporal variations in the received signal quality, which may affect the quality-of-service of the underlying application. Therefore, it is crucial to characterize the time-varying process of signal quality observed by the UAVs. In this paper, we consider a scenario in which a cellular-connected UAV acts as a user equipment (UAV-UE), where the locations of base stations (BSs) follow a Poisson point process (PPP) and the UAV-UE is moving along a 3GPP-inspired straight-line trajectory. For this setting, we study the properties of the time-varying successful transmission process that is defined in terms of the time-varying signal-to-noise ratio (SNR) observed at the UAV. In particular, we show that this process is a wide sense stationary (WSS) process and derive its first- and second-order statistics. Finally, we establish an equivalence between the successful transmission processes observed by a UAV-UE served by terrestrial BSs and a terrestrial user served by UAV mounted BSs (UAV-BSs) each moving along an independent straight-line trajectory.