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This paper presents a novel frequency selective surface (FSS) structure with miniaturized, rapid band edge, ultra-wideband (UWB) passband, and UWB out of band shielding. The proposed FSS is formed by using two air foam layers to cascade three single layers with the unit cell dimension in 6mm $\times 6$ mm( $0.023\lambda \times 0.023\lambda $ . The corresponding equivalent circuit models are developed for interpretation of the physical mechanism and formulate the relevant design equations. Finally, a prototype of the proposed structure is fabricated and measured to verify the full-wave simulation and theoretical analysis results. The measured results show the proposed FSS has a −3 dB passband from 1.17 GHz to 7.08 GHz and a −10 dB stopband from 7.34 GHz to 15.0 GHz. The corresponding relative bandwidths calculated from the measured results are 143.3% and 68.6%, respectively, which exhibits the stable performance against the variation of the incident angles from 0° to 45° for both TE and TM polarizations. All these results demonstrate that the proposed FSS is suitable for the actual miniaturized EMI shielding scene application.

Infrastructure-as-a-Service clouds provide out-of-band remote management of the systems in virtual machines (VMs). This management method enables users to manage their systems even on several types of failures inside VMs. In this method, users access virtual devices of their VMs, but virtual devices are not sufficiently protected against untrusted cloud operators. For secure out-of-band remote management, previous work securely runs shadow devices outside an untrusted virtualized system using nested virtualization. However, the states of shadow devices are lost during VM migration. In this paper, we propose USShadow for continuing secure out-of-band remote management after VM migration. USShadow enables the migration manager inside the virtualized system to transparently and securely save and restore the states of shadow devices outside it. We have implemented USShadow, which supports Xen and KVM as virtualized systems. Then, we confirmed that USShadow could continue virtual serial console and that the migration overhead was negligible., 2020 IEEE 13th International Conference on Cloud Computing (CLOUD 2020), 18–24 October, 2020, Beijing, China（オンライン開催に変更）

Noncontiguous orthogonal frequency division multiplexing (NC‐OFDM)‐based cognitive radio (CR) systems achieve highly efficient spectrum utilization by transmitting unlicensed users' data on subcarriers of licensed users’ data when they are free. However, there are two disadvantages to the NC‐OFDM system: out‐of‐band power (OBP) and a high peak‐to‐average power ratio (PAPR). OBP arises due to side lobes of an NC‐OFDM signal in the frequency domain, and it interferes with the spectrum for unlicensed users. A high PAPR occurs due to the inverse fast Fourier transform (IFFT) block used in an NC‐OFDM system, and it induces nonlinear effects in power amplifiers. In this study, we propose an algorithm called “Alternative Projections onto Convex and Non‐Convex Sets” that reduces the OBP and PAPR simultaneously. The alternate projections are performed onto these sets to form an iteration, and it converges to the specified limits of in‐band‐power, peak amplitude, and OBP. Furthermore, simulations show that the bit error rate performance is not degraded while reducing OBP and PAPR.

With a tremendous amount of underutilized bandwidth, millimeter wave (mmWave) communication is a promising solution to meet the increasing data-rate demands. To deal with high pathloss in mmWave frequency band, efficient large antenna arrays become crucial to provide necessary beamforming and spatial multiplexing gains. Hybrid analog/digital beamforming has been an encouraging technique in order to reduce the complexity and power consumption of large antenna arrays. In this paper, we propose a low-complexity two-stage hybrid analog/digital precoding and combining scheme for downlink multi-user multi-RF-chain mmWave systems using out-of-band spatial information to minimize the mean-squared error (MMSE) in receiving data streams. Particularly, according to sparse spatial characteristics of the mmWave channel, we utilize more efficient Grassmannian codebooks as the training codebooks to generalize a strategy of utilizing sub-6GHz spatial information for constructing multiuser mmWave communication links. The multiuser analog beamforming problem is then formulated as a weighted sparse signal recovery problem with the weights obtained from sub-6GHz spatial information. In addition, the digital precoding and combining scheme is derived using an efficient MMSE scheme for multi precoders at transmitters and combiners at receivers. Numerical results show the obvious advantages of the proposed multi-user hybrid analog/digital precoding/combining design for various practical scenarios.

This article describes a dual-band diffusive metasurface-based reflector, with a specular reflection band together with two sidebands which exhibit low radar cross-section (RCS). A rhombus-shaped patch-ring type of polarizer with dual-band characteristics is chosen as the fundamental unit cell. The polarizer and its mirror structure have opposite phases in the polarization-rotating bands, while their phase is the same in the reflection band, which is juxtaposed in-between the middle of the two polarization-rotating bands. The designed metasurface is constructed, based on the phase cancellation theory, by arranging arrays of these two unit cells in a two-dimensional pattern. The measured results show that the realized metasurface-based reflector achieves a high-efficiency specular window from 26.2 to 38.8 GHz together with two low-RCS sidebands from 18.18 to 24.6 GHz and 40.61 to 56.4 GHz. The proposed diffusive metasurface can be potentially used as a reflector for reflector antennas, which provides a highly efficient in-band radiation together with low backscattering out-of-band.

From the points of spectral efficiency, low latency and massive connectivity, novel modulation and multiple access schemes have been proposed in fifth generation (5G) wireless networks. However, the combinations of multiplexing and multiple access techniques have not been widely investigated in most literatures. Therefore, we joint generalized frequency division multiplexing (GFDM) waveforms and power-domain non-orthogonal multiple access (NOMA) systems together in order to further extend the framework of multi-carrier NOMA, and also achieve performance evaluations for NOMA networks with one base station and two users. Basically, theoretical BER expressions of downlink and uplink GFDM assisted NOMA schemes are mathematically derived and then verified by simulation results. In addition, combined performance advantages, including higher achievable sum rate, lower peak-to-average power ratio (PAPR) and out of band power (OOBP) radiation, can be obtained in GFDM assisted NOMA networks.

This thesis has been carried out on behalf of the department of Digital Services - SDI at Ericsson. Ericsson Software Defined Infrastructure (SDI) is a telco grade hardware management solution for cloud infrastructure. In datacenter deployments, the extra management equipment needed by the solution becomes insignificant due to the amount of equipment it manages. But the closer to the cloudedge you get, the smaller in size the deployments become, thus making the management equipment an ever-increasing share of the total deployment seize leading to inefficient resource utilization, so called overhead. Especially with Distributed Radio Access Networks (RAN) many small deployments, often only consisting of a single compute-server used to process radio, will be deployed at radio sites and/or in buildings around cities to deliver cell service. In this type of usage, the overhead of equipment management builds up cumulatively due to the numerous amounts of deployments. This overhead leads to excessive maintenance, power usage, space needs for equipment, costs, and electronic waste. The goal of this thesis was to evaluate how to reduce the overhead of equipment management in a scenario involving numerous small-capacity widely-distributed sites which are common in the 5G telco cloud. The idea was to determine if the overhead could be reduced by exploiting Baseboard Management Controllers (BMC), this was tested by designing a low-footprint and lightweight proof of concept equipment management solution and implementing a prototype of it. By testing, verifying, and analyzing the proof-of-concept solution, it was concluded that by exploiting the BMC to run a custom software service that phoned home to a centralized management server it was possible to drastically reduce the overhead in such scenarios. It also became clear that BMCs could have even more usage areas and provide even greater value if support to run third partyapplications existed among them. Detta examensarbete har utförts på uppdrag av avdelningen Digital Services - SDI på Ericsson. Ericsson Software Defined Infrastructure (SDI) är en hårdvaruhanteringslösning av telekomkvalitetför molnifrastruktur. I datacenterinstallationer blir den extra hanteringsutrustning som behövs av lösningen obetydlig på grund av mängden utrustning den hanterar. Men ju längre ut till molnkanten du kommer, desto mindre blir storleken på installationerna, vilket gör att hanteringsutrustning blir en ständigt ökande andel av den totala installationsstorleken som leder till ineffektivt resursutnyttjande, så kallat overhead. Speciellt med Distribuerade Radio Access Nätverk (RAN) så kommer många små installationer, ofta endast bestående av en enda server som utför radiolänksberäkningar, att vara fysiskt utplacerade vidbasstationer och/eller i byggnader runt städer för att leverera och tillhandage mobiltjänster. Vid denna typ av användning ökar overheadet för utrustningshanteringen kumulativt på grund av antalet installationer. Detta overhead leder till mer underhåll och elektroniskt avfall, större utrymmesbehov för utrustning samt högre strömförbrukning och kostnader. Målet med detta examensarbete var att utvärdera hur man kan minska overheadet hosutrustningshantering när det tillämpas på ett stort antal, små decentraliserade distribuerade installationer, vilket är förekommande i telekommoln. Idén var att undersöka om overheadet kunde minskas genom att utnyttja Baseboard Management Controllers (BMC), detta testades genom att designa en liten och lättviktigt konceptlösning för utrustningshantering samt implementera en prototyp av den. Genom att testa, verifiera och analysera konceptlösningen drogs slutsatsen att det var möjligt att drastiskt minska overheaden i sådana scenarion genom att utnyttja BMC att köra en egen mjukvarutjänst, som automatiskt anslöt till en central hanteringsserver. Genom arbetet blev det också tydligt att BMC:er skulle kunna ha ännu fler användningsområden och ge ännu större värde om stödet för att köra tredjepartsapplikationer på dem var mer utbrett

One promising and competitive solution to keep up with the rapid growth in data traffic while at the same time addressing increasing network cost, is the efficient reuse of legacy optical fiber infrastructure. This is highly desirable as deployed single mode fibers represent a valuable asset in the network while new installations would require high additional investments. Multiband (MB) or ultra-wideband (UWB) systems, combined with high symbol rates and higher-order modulation formats, are promising solutions to capitalize the already existing fiber plants. In this contribution, we experimentally demonstrate S-C-L-band reception with 64 GBd dual-polarization (DP) 64-ary and 32-ary quadrature-amplitude modulation (QAM) while using C band components off the shelf (COTS) such as DP-IQ modulators and coherent receivers. To achieve such broadband operation with components that are not optimized for an out of band use, mitigation of the associated penalties is decisive. To this end, we apply an end-to-end electro-optical Volterra based coherent system identification followed by nonlinear digital predistortion of the transmitter. We achieve 150-nm operation bandwidth of the transmission system by performing only a single identification and predistortion at a reference wavelength of 1500 nm.

Linearization and peak to average power ration reduction are two classical operations when non-linear power amplifiers (PA) are used. If only PA linearization is considered, the high crest factor (PAPR) of the amplified signal causes saturation when input power is higher than the PA saturation power. If only PAPR reduction is implemented alone, PA non-linearities will degrade the signal at low input backoff (IBO). It is necessary to combine the two methods in order to operate the PA with low IBO while having low in band and out of band degradations. Hybrid methods modify both the architecture of the PA for linearization purposes and the PAPR reduction of the amplified signals. In this paper two hybrid methods: Iterative Dichotomy PAPR Reduction (IDP) and Linear amplification using nonlinear components (LINC) are compared in terms of energy efficiency and implementation complexity. Two real PA models with different output saturation powers are used (45dBm and 15dBm) and the power dedicated to the algorithm implementations are quantified using an FPGA implementation. Simulation results shows that the IDP method outperforms the LINC one in terms of energy efficiency.

Millimeter-wave (mm-wave) communication has been widely applied in the small cellular networks, and it is not difficult to find that mm-wave plays an important role in improving the capacity and data transmission rate of the 5G network systems. Nevertheless, mm-waves also have some disadvantages, such as large propagation loss and weak penetration blockage. Although the extremely high direction of the mm-wave can compensate for the propagation loss, highly directional transmissions of the mm-wave result in conventional omnidirectional transmission cell discovery schemes may fail in mm-waves; thus, we need to redesign the cell discovery scheme of mm-wave. In addition, the overhead of mm-wave cell discovery is also large. In order to reduce the overhead and provide a reasonable solution for the mm-wave base station (BS) discovery, we propose an analysis framework that utilizes out-of-band (OOB) information assistance. First, we consider the BS discovery problem as a hypothesis test problem. We analyze the statistical properties of the generalized logarithm likelihood ratio detector and study the detection performance of the detector. Through analysis and calculation, we are able to find that the OOB scheme can not only improve the detection performance but also reduce the system overhead. Then, we also analyze the performance of the OOB scheme in the case of multiple UEs. Finally, we use the angle information provided by the OOB information to predesign the mm-wave codebooks to achieve the optimal expected mode. Analysis of the simulation results demonstrates the effectiveness of the OOB information-assisted scheme.

Communication, compression of information, transmission of information through noisy channels, interconnecting different information systems, cryptography, gate construction –– these areas all depend on classical information theory. We show that, in classical terms, semantic aspects of communication are not at all irrelevant to the engineering problem, contrary to Shannon, and affect the message intended to be transmitted. This is revisited and captured by an analogy to trust, in that they are essential to the channel (for proper use), but cannot be transferred (under risk of flaws) through that same channel. Information is also described by, at least, a tri-state system — not by binary logic. The trust analogy semantics can be coded as the Curry-Howard relationship, connecting computer code with structural logic, by way of different categories. Two-state and Boolean logic (aka Shannon semantics) was used classically before, with Shannon theory, but without trust analogy semantics – found to be a sine qua non condition. This is now familiar in classical gate construction with physical systems with, e.g., Verilog and SystemVerilog. The applications to computation and quantum theory are further explored. The most fundamental entity in today`s theory of information is proposed to use at least three logical states, not bits, in all applications, including: cyber-physical systems, devices, in computation, and in quantum theory.

Transversal networks for electroacoustic filters had been proposed and manufactured recently. One of the main problems that arose in the first prototype were the spurious modes due to the mirror stack of the Solidly Mounted Resonators (SMR). In this work, different approaches for solving this problem are discussed, relying on Mason's circuit-based simulations of each resonator and of the filter topology. The main drawbacks and advantages of the different approaches are discussed in terms of fabrication and mirror efficiency. This work was supported in part by the Catalan Government under Grant 2017 SGR 813, in part by the Spanish Government under Grant TEC2017-84817-C2-2-R and Grant TEC2017-88343-C4-2-R, and was also supported by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through grant 2020 FI_B-00967.

Digital Predistortion (DPD) is an effective technique for Power Amplifier (PA) non-linear distortion and memory effects compensation. Different topoligies of DPD are presented in the literature. In this paper, we propose a mimetic neural network based DPD for Hammerstein power amplifier for OFDM signal with a reduction of Peak to Average Power Ration (PAPR) by Selective Mapping (SLM) method. This proposed model is compared with Real Valued Multilayer Perceptron (R-MLP). Simulation results show that the mimetic-R-MLP manifests more efficiency for PA linearization and for memory effect reduction in terms of Error Vector Magnitude (EVM) by a gain of 2 dB. It outperforms the R-MLP in terms of Mean Squared Error (MSE) for the convergence of the Neural Network (NN) and its complexity is \(23\%\) lower. The results in terms of Power Spectral Density (DSP) show also that our model compensates efficiently the out of band distortion (OOB) of the PA.

© 2004-2012 IEEE. In this brief, a class of microstrip bandpass filters (BPFs) with quasi-reflectionless behavior on both input and output ports is presented. A single-port reflectionless BPF is proposed by shunt connecting one bandstop filter cell namely one-cell. This one-cell single-port reflectionless BPF is made up of a high impedance transmission line as a series band-pass filter section and a shunt-connected band-stop section with resistively terminated. In the operation passband, the bandpass filter section is used to transmit spectral energy, while the bandstop section is regarded as an open circuit. Besides, the out-of-band energy is absorbed by resistively component in the bandstop filter section. In order to achieve better out-of-band reflectionless characteristic, a two-cell two-port reflectionless BPF is constructed by shunt connecting two cells at input/output ports and one series bandpass filter section in the center. In addition, a three-cell reflectionless BPF is designed to further verify the improvement of out-of-band performance. Finally, two-cell and three-cell two-port reflectionless BPFs are fabricated and tested to verify the design concept. The measured results of these two reflectionless BPFs are in good agreement with the simulation ones.

For the paper, experimental studies were performed on the damage of the Ge- and Si-based flat window by lasers out-of-band. The experimental results showed that lasers out-of-band can cause film damage and substrate damage to Ge and Si windows. The high-energy laser damage window mechanism mainly manifested as thermal effects. The composite laser damage thresholds for the substrate were an Si window of 21.6 J/cm2 and a Ge window of 3 J/cm2. Compared with continuous laser and long pulse laser experimental results, it was found that the use of long pulse-continuous composite constitution could effectively reduce the damage threshold. Compared to the long-pulse laser, the composite laser could achieve similar damage effects with a smaller energy density.

An ultra low power mixer with out-of-band radio frequency (RF) energy harvesting suitable for the wireless sensors network (WSN) application is proposed in this paper. The presented mixer is able to harvest the out-of-band RF energy and keep it working in ultra low power condition and extend the battery life of the WSN. The mixer is designed and simulated with Global Foundries ’ 0.18 μ m CMOS RF process, and it operates at 2.4GHz industrial, scientific, and medical (ISM) band. The Cadence IC Design Tools post-layout simulation results demonstrate that the proposed mixer consumes 248 μ W from a 1V supply voltage. Furthermore, the power consumption can be reduced to 120.8 μ W by the out-of-band RF energy harvesting rectifier.

International audience; For the first time, we demonstrate in this paper an intensity-modulation direct-detection (IMDD) universal filtered multi-carrier (UFMC) system through several hundred meters of multimode fiber (MMF) that can be adopted for 5G communications and beyond. The proposed system is simulated and evaluated in terms of bit error rate (BER), Q factor, out of band (OOB) emission and Peak-to-Average Power Ratio (PAPR), at a data rate of 10 Gb/s. It is shown that filtering used with UFMC reduces the OOB radiation by 40 dB compared to orthogonal frequency division multiplexing (OFDM). Moreover, we prove that UFMC gives lower values of BER than OFDM, and even if the PAPR ratio of UFMC is higher than OFDM, the gap remains small. The results also show that using a Volterra equalizer with increasing taps enables to obtain acceptable performance through the MMF in terms of BER, even with high number of excited mode groups.

Usage of faster than Nyquist signaling (FTN) in practice is limited by the complexity of the formation and detection devices. Optimal FTN pulses may be formed via digital non-recursive filters. One of the important parameters that affect the performance of such devices is the number of quantization levels. In this paper, the influence of the number of quantization levels for optimal FTN signals with pulse-amplitude modulation on spectral characteristics, correlation properties and the probability of error detection is investigated. It is shown that at least 64 quantization levels should be chosen to provide almost potential bit error rate performance and additional spectral quantization noise about – 40 dB for volumes of channel alphabet upto 8. Decreasing the volume of channel alphabet allows reducing the requirements for the number of quantization levels.

QUIC is a secure transport protocol that improves the performance of HTTPS. An initial QUIC handshake that enforces a strict validation of the client's source address requires two round-trips. In this work, we extend QUIC's address validation mechanism by an out-of-band validation token to save one round-trip time during the initial handshake. The proposed token allows sharing an address validation between the QUIC server and trusted entities issuing these tokens. This saves a round-trip time for the address validation. Furthermore, we propose distribution mechanisms for these tokens using DNS resolvers and QUIC connections to other hostnames. Our proposal can save up to 50% of the delay overhead of an initial QUIC handshake. Furthermore, our analytical results indicate that 363.6ms in total can be saved for all connections required to retrieve an average website, if a round-trip time of 90ms is assumed., 8 pages

International audience; We investigate preamble designs for channel estimation that jointly address the estimation efficiency and the out of band (OOB) radiation of the transmit preambles. Accordingly, we provide two novel techniques for obtaining preambles for a single carrier system. Furthermore, we give a juxtaposition based method to extend their application to multi-carrier systems. The obtained preambles have 10 dB to 35 dB lower OOB radiation than the existing preamble based estimation techniques in literature. We also bring out the fundamental trade-off that exists between the estimation efficiency and the OOB radiation power, and highlight that the improved OOB performance comes at a cost of increased estimation error. Finally, as a case study, we study the performance of the obtained preambles in a multiple input multiple output (MIMO) Generalized Frequency Division Multiplexing ( GFDM) system, aimed for transmit diversity.

The out-of-band (OOB) response is one of the key specifications for satellite optical sensors, which has important influences on quantitative remote sensing retrieval. In this paper, the effect of OOB response on the radiometric measurements made just above the sea surface is evaluated for the three broad visible bands (i.e., blue, green, and red) of the Coastal Zone Imager (CZI) onboard China’s ocean satellite HY-1C to be launched in September 2018. For the turbid coastal (Case 2) waters whose optical properties are mainly dominated by suspended sediment and colored dissolved organic material, the OOB effect can be neglected (&lt, 2%) for all three CZI visible bands. For the phytoplankton-dominated (Case 1) waters which are mainly distributed in the clear open ocean, a significant (&gt, 2%) OOB effect was found in the green band over oligotrophic waters (chlorophyll a concentration ≤~0.1 mg/m3), and accordingly a model based on the CZI blue-green band ratio is proposed to correct this effect. The OOB influence on the CZI ocean color retrieval is discussed. This research highlights the importance of the comprehensive pre-launch radiometric characterization and the OOB effect correction for the broad band space-borne sensor, in order to achieve a high-quality quantitative ocean product.

In this paper a Dynamic Spectrum Access (DSA) Physical layer (PHY) technique is proposed that allows Secondary User (SU) access to the traditional FM Radio spectrum (88-108 MHz) for alternative data communication applications. FM radio waves have excellent propagation characteristics for long distance transmission, and have high levels of penetration through buildings. Using tools such as a structured geolocation database of licensed Primary User (PU) FM Radio transmitters, unlicensed SUs can access portions of the 20 MHz-wide band and transmit signals that place spectral ‘holes’ with suitable guard bands around all known PUs. Based on the PU protection ratios published by Ofcom and the FCC, the operation of a FBMC (Filter Bank Multi-Carrier) transmitter is demonstrated for an urban environment, and through ‘field test’ simulation it is shown that the Out Of Band (OOB) leakage of the proposed PHY (energy in the ‘holes’ that can interfere with the PU) is 47 dB lower than that of using an equivalent OFDM PHY. The results show that the proposed PHY is a suitable candidate for DSA-SU communication (e.g. in smart city IoT applications), whilst ensuring the integrity of incumbent PU signals.

International audience; In this paper, Filter Bank Multi Carrier (FBMC) signals are employed in order to improve the performance of a quasi-passive wake-up radio receiver (WuRx) for which the addressing is performed by the means of a frequency fingerprint. The feasibility of such kind of WuRx was already demonstrated by using orthogonal frequency-division multiplexing (OFDM) signals to form the identifiers. Together with the main advantage of this approach (i.e. no base band processing needed and consequently a reduced energy consumption), one of the drawbacks is their low sensitivity. Through a set of circuit-system co-simulations, it is shown that by their characteristics, especially high Peak to Average Power Ratio (PAPR) and high out of band attenuation, FBMC signals manage to boost the sensitivity and moreover to enhance the robustness of this kind of WuRx.

International audience; This paper deals with the effects of an electromagnetic interference (EMI) from an out-of-band signal impinging on a 2.4 GHz RF receiver operating in the linear regime. The injection signal is radiated in the near-field above the circuit package at a frequency of 60 GHz. Due to the nonlinear behavior of active devices, we observed a gain quenching leading to a complete inhibition of the receiver that occurs together with a current overconsumption. Disruptions are experimentally studied depending on the position above the package, the distance between the EMI source and the circuit, as well as the frequency used to switch on and off the millimeter source.

Millimeter wave (mmWave) communication is one feasible solution for high data-rate applications like vehicular-to-everything communication and next generation cellular communication. Configuring mmWave links, which can be done through channel estimation or beam-selection, however, is a source of significant overhead. In this paper, we propose to use spatial information extracted at sub-6 GHz to help establish the mmWave link. First, we review the prior work on frequency dependent channel behavior and outline a simulation strategy to generate multi-band frequency dependent channels. Second, assuming: (i) narrowband channels and a fully digital architecture at sub-6 GHz; and (ii) wideband frequency selective channels, OFDM signaling, and an analog architecture at mmWave, we outline strategies to incorporate sub-6 GHz spatial information in mmWave compressed beam selection. We formulate compressed beam-selection as a weighted sparse signal recovery problem, and obtain the weighting information from sub-6 GHz channels. In addition, we outline a structured precoder/combiner design to tailor the training to out-of-band information. We also extend the proposed out-of-band aided compressed beam-selection approach to leverage information from all active OFDM subcarriers. The simulation results for achievable rate show that out-of-band aided beam-selection can reduce the training overhead of in-band only beam-selection by 4x., 30 pages, 11 figures

This paper proposes digital cancellation of nonlinear distortion originating from out-of-band blocking carriers and induced by the analog front-end nonlinearities in direct-conversion receivers (RXs). The cancellation is enabled by employing an additional reference RX for capturing these blockers. In addition, cancellation of mirror-frequency interference is targeted. The feed-forward cancellation of nonlinear distortion is blindly adaptive without any a priori information of the received signal or the nonlinearity characteristics of the RX. The performance of this approach is demonstrated with laboratory RF measurements using state-of-the-art base-station hardware. With the distortion cancellation, blocker tolerance of the RX is improved by 7–8 dB.

As in most RF circuits, the design of transmitters for advanced mobile communication systems is dominated by the tradeoff between cost and performance. While the former claims ever-smaller footprints and bill of materials (BOM), the latter comprises a stringent set of requirements regarding power consumption, signal integrity and out-of-band noise emission. Analog-intensive architectures [1,2] typically deliver the best noise performance at the cost of intensive lowpass filtering, hence increasing area consumption with bulky reconstruction filters. The digital transmitters [3–5], on the other hand, are significantly more portable and area efficient, but they typically fall short in terms of out-of-band noise and spurious emission. A charge-based architecture was presented in [6], using incremental signaling in a switched-capacitance architecture to provide intrinsic noise-filtering capabilities with small power and area consumption. This work presents a transmitter architecture that leverages the incremental-charge-based operation by using power-efficient resistive DACs to deliver charge directly to the 50Ω output RF load, omitting the need for a PA driver stage, in a complete digital-intensive architecture. With a peak output power of 3.5dBm, the presented work achieves −159dBc/Hz at 45MHz offset from both 900MHz and 2.4GHz modulated carriers, with an EVM performance of −36dB for a 64-QAM modulated signal.

In this brief, a 28.8-MHz −3-dB frequency low-pass analog filter is presented. The filter synthesizes a fourth-order Butterworth transfer function, exploiting the well-known Sallen-Key (SK) biquadratic cell. The out-of-band zeros typically present in SK implementations are hereby completely canceled by using a low-power auxiliary path. This leads to a significant improvement of the stop-band rejection, at the cost of a small power for the same auxiliary path biasing. The design exhibits very large in-band IIP3 over the entire filter bandwidth (20 dBm at 10 MHz and 11 MHz), at 3.2-mW power consumption. The filter prototype has been designed in CMOS 0.18- $ {\mu }\text{m}$ technological node. The total area occupancy is 0.12 mm $^{ {2}}$ and the in-band integrated noise is $101~ {\mu }{\mathrm{V}}_{\mathrm{RMS}}$ .

An investigation on the stop band behaviour of TM dual-mode filters has been conducted in order to identify ways to suppress or alleviate the presence of spurious out-of-band resonances. Two types of spurious resonances have been identified: iris and cavity resonances. Both resonances can be shifted to higher frequencies: the former by using multi aperture irises or multiple irises, the latter by modifying the cavity geometry. In this paper the conventional square cavities are replaced by circular cavities, taking advantage from some modal properties of the circular geometry. The presented strategies are used in order to improve the upper stop-band of a manufactured four-pole TM filter with four transmission zeros presented in [12], obtaining an increase up to 370%.

Adjacent channel interference (ACI) between OFDM signals severely impacts system performance and spectrum efficiency. To eliminate ACI, Active Interference Cancelation (AIC) techniques using additional modulated OFDM sub-carriers can be adopted. This paper describes an AIC technique based on multi-step calculation of clipped canceling symbols. The algorithm has simple implementation and allows to easily control the extra power required for canceling symbols. To avoid bandwidth expansion, non-orthogonal canceling sub-carriers (E-AIC) can be easily incorporated in the procedure. The achievable reduction of the OFDM spectrum tail power has been evaluated analytically and by simulation.

A novel technique for mitigating the optical beat interference (OBI) noise in an optical orthogonal frequency division multiple access passive optical network (OFDMA-PON) uplink transmission is presented. By using an out of signal band RF clipping tone to the optical seed carrier, the OBI noise has been reduced and the resulting throughput and spectral efficiency has been improved. As an experimental verification, we demonstrate that the spectral efficiency of 23 km and 50 km have been doubled in the OFDMA-PON uplink transmission. (C) 2014 Optical Society of America

OpenFlow is a protocol that enables networks to evolve and change flexibly, by giving a remote controller the capability of modifying the behavior of network devices. In an OpenFlow network, each device needs to maintain a dedicated and separated connection with a remote controller. All these connections can be described as the OpenFlow control network, that is the data network which transports control plane information, and can be deployed together with the data infrastructure plane (in-band) or separated (out-of-band), with advantages and disadvantages in both cases. The control network is a critical subsystem since the communication with the controller must be reliable and ideally should be protected against failures. This paper proposes a novel ring architecture to efficiently transport both the data plane and an out-of-band control network. The authors would like to acknowledge the support of the Spanish projects CRAMnet (grant no. TEC2012-38362-C03-01) and FIERRO (grant no. TEC2010-12250-E) to the development of this work.

The two-user Gaussian interference channel with a shared out-of-band relay is considered. The relay observes a linear combination of the source signals and broadcasts a common message to the two destinations, through a perfect link of fixed limited rate $R_0$ bits per channel use. The out-of-band nature of the relay is reflected by the fact that the common relay message does not interfere with the received signal at the two destinations. A general achievable rate is established, along with upper bounds on the capacity region for the Gaussian case. For $R_0$ values below a certain threshold, which depends on channel parameters, the capacity region of this channel is determined in this paper to within a constant gap of $\Delta=1.95$ bits. We identify interference regimes where a two-for-one gain in achievable rates is possible for every bit relayed, up to a constant approximation error. Instrumental to these results is a carefully-designed quantize-and-forward type of relay strategy along with a joint decoding scheme employed at destination ends. Further, we also study successive decoding strategies with optimal decoding order (corresponding to the order at which common, private, and relay messages are decoded), and show that successive decoding also achieves two-for-one gains asymptotically in regimes where a two-for-one gain is achievable by joint decoding; yet, successive decoding produces unbounded loss asymptotically when compared to joint decoding, in general., Comment: Submitted to IEEE Transactions on Information Theory

A Gaussian interference channel (IC) aided by a half-duplex relay is considered, in which the relay receives and transmits in an orthogonal band with respect to the IC. The system thus consists of two parallel channels, the IC and the channel over which the relay is active, which is referred to as Out-of-Band Relay Channel (OBRC). The OBRC is operated by separating a multiple access phase from the sources to the relay and a broadcast phase from the relay to the destinations. Conditions under which the optimal operation, in terms of the sum-capacity, entails either signal relaying and/or interference forwarding by the relay are identified. These conditions also assess the optimality of either separable or non-separable transmission over the IC and OBRC. Specifically, the optimality of signal relaying and separable coding is established for scenarios where the relay-to-destination channels set the performance bottleneck with respect to the source-to-relay channels on the OBRC. Optimality of interference forwarding and non-separable operation is also established in special cases., 5 pages, 5 figures, to appear in Proceedings of IEEE ISIT 2010

In this paper a method is proposed to compensate for the nonlinear distortions present in the input signal of a DUT which results in a source-pull free level of the output nonlinear distortions. This allows to determine an accurate adjacent co-channel power ratio (ACPR). The proposed measurement technique is based on a vector network analyzer (PNA-X) and uses a broadband multisine excitation. Results obtained from a microwave amplifier are reported.

This paper considers the use of the reverberation chamber as a possible facility to test equipment, illuminated by multiple sources, in order to ascertain their susceptibility to in-band effects caused by intermodulation from two or more out-of-band signals. The work is premised on the fact that issues with signal integrity may not be dominated with direct single-source threats but may be substantially affected by intermodulation from two or more signals that would, themselves be filtered out of the system, combining through active (or possibly passive) intermodulation to give rise to a noise signal that is within the consideration band of the signal whose integrity is paramount. The purpose of the paper is to present the results of a first series of simulation experiments that indicate that a simple approach to multiple source testing may be effective as a basis for a more extensive set of tests.

Most of previous works on optical burst switching (OBS) assume in their analysis that signalling does not affect network performance. In this paper we analyze under which conditions the effect of signalling is actually negligible, taking into account the effect of signalling in the evaluation of burst discard probability. We use two analytical models for two different signalling techniques in an OBS network: out-of-band and in-band technique. We evaluate the impact of these two signalling strategies in term of the probability of burst discard. We also discuss a new method to assign the correct amount of resources to the control plane. To verify the accuracy of the proposed models, analytical results are compared with results based on discrete-event simulations and are found to be in very satisfactory agreement.