Showing papers by "Alcatel-Lucent published in 2017"

Shockley-Read-Hall and Auger non-radiative recombination in GaN based LEDs: A size effect study

Abstract: GaN-based micro light-emitting diode (μLED) arrays are very promising devices for display applications. In these arrays, each μLED works as a single pixel of a whole image. The electro-optical performance of these μLEDs is an important subject to study. Here, we investigate the influence of LED size on the radiative and non-radiative recombination. The standard ABC model has been widely used to describe the efficiency of GaN based LEDs. Using this model, we extract A, B, and C coefficients for various LED sizes, showing how the competition between radiative and non-radiative recombination processes varies with the LED geometry. Time-resolved photoluminescence allows us to determine coefficient B, related to radiative recombination. Through current-voltage-luminance characterizations, we determine parameters A and C related to Shockley-Read-Hall and Auger recombination. We find that coefficient A is strongly dependent on LED size, indicating a drastic effect of sidewall defects on the performance of LEDs. ...

A Sparse Coding Approach to Household Electricity Demand Forecasting in Smart Grids

Abstract: With the gradual deployment of smart meters in many cities around the world, new opportunities arise in reducing energy usage and improving consumers’ information and control on their electricity consumption. Central to the provision of these newer services is the ability to accurately forecast the electricity demand of individual households. Compared with load forecasting at the city level and larger system aggregates, load forecasting for individual households is a much harder problem as the loads are much more stochastic and volatile. In this paper, we study the use of sparse coding for modeling and forecasting these individual household electricity loads. The proposed methods are tested on a data set of 5000 households in a joint project with electric power board of Chattanooga, for the period from September 2011 to August 2013. We obtain 10% improvements in the accuracy of forecasting next-day total load and next-week total load when we add sparse code features in ridge regression in this difficult problem. We also evaluate more classical forecasting methods on this forecasting problem, including autoregressive integrated moving average and Holt-Winters smoothing.

An Enhanced MPPT Method Combining Fractional-Order and Fuzzy Logic Control

Abstract: A fractional-order fuzzy logic control (FOFLC) method for maximum power point tracking (MPPT) in a photovoltaic (PV) system is presented. By combining the robustness of fuzzy logic with the accuracy of fractional order, the proposed method can improve the tracking accuracy in weather variations compared with the conventional fuzzy MPPT. First, the fractional-order factor is carefully selected according to the dynamic range of the fuzzy controller. It takes a bigger alpha factor in the first place to expand the fuzzy domain and shortens the time of searching for the MPP. When the maximum power point is approached, it uses a smaller the alpha factor to contract the fuzzy domain and eliminates the oscillations at the MPP. Therefore, the FOFLC in a PV system has rapid dynamic responses under environment variations and high tracking accuracy of the maximum power point. Second, MATLAB/Simulink software is employed to simulate a PV power system and verify the proposed algorithm by various simulations. The enhanced MPPT algorithm has been implemented on a field programmable gate array (FPGA) board. Finally, a boost dc–dc converter experiment has been carried out to evaluate the system performance. The simulation and experiment results show that this method can improve the transient and steady-state performance simultaneously.

Collaborative Filtering-Based Recommendation of Online Social Voting

Abstract: Social voting is an emerging new feature in online social networks. It poses unique challenges and opportunities for recommendation. In this paper, we develop a set of matrix-factorization (MF) and nearest-neighbor (NN)-based recommender systems (RSs) that explore user social network and group affiliation information for social voting recommendation. Through experiments with real social voting traces, we demonstrate that social network and group affiliation information can significantly improve the accuracy of popularity-based voting recommendation, and social network information dominates group affiliation information in NN-based approaches. We also observe that social and group information is much more valuable to cold users than to heavy users. In our experiments, simple metapath-based NN models outperform computation-intensive MF models in hot-voting recommendation, while users’ interests for nonhot votings can be better mined by MF models. We further propose a hybrid RS, bagging different single approaches to achieve the best top- $k$ hit rate.

BalCon: A Distributed Elastic SDN Control via Efficient Switch Migration

Abstract: Scalability and reliability are among the main concerns in large-scale Software Defined Networking (SDN) application scenarios. A common approach is to use multiple distributed controllers, each managing one static partition of the network. In this paper, we show that dynamic mapping can improve efficiency in managing traffic load variations. We then propose BalCon (Balanced Controller): an algorithmic solution designed to tackle and reduce the load imbalance among SDN controllers through proper SDN switch migrations. Simulations demonstrate that BalCon is lightweight from the computational point of view and reduces the load imbalance among SDN controllers (expressed as variance) by 40% by migrating only a small number of switches. We also built a realistic prototype of SDN controller, BalConController, based on the open-source SDN framework RYU.

Exponentially Weighted Particle Filter for Simultaneous Localization and Mapping Based on Magnetic Field Measurements

Abstract: This paper presents a simultaneous localization and mapping (SLAM) method that utilizes the measurement of ambient magnetic fields present in all indoor environments. In this paper, an improved exponentially weighted particle filter was proposed to estimate the pose distribution of the object and a Kriging interpolation method was introduced to update the map of the magnetic fields. The performance and effectiveness of the proposed algorithms were evaluated by simulations on MATLAB based on a map with magnetic fields measured manually in an indoor environment and also by tests on the mobile devices in the same area. From the tests, two interesting phenomena have been discovered; one is the shift of location estimation after sharp turning and the other is the accumulated errors. While the latter has been confirmed and investigated by a few researchers, the reason for the first one still remains unknown. The tests also confirm that the interpolated map by using the proposed method improves the localization accuracy.

Base Station Diversity Propagation Measurements at 73 GHz Millimeter-Wave for 5G Coordinated Multipoint (CoMP) Analysis

Abstract: This paper describes wideband (1 GHz) base station diversity and coordinated multipoint (CoMP)-style large-scale measurements at 73 GHz in an urban microcell open square scenario in downtown Brooklyn, New York on the NYU campus. The measurements consisted of ten random receiver locations at pedestrian level (1.4 meters) and ten random transmitter locations at lamppost level (4.0 meters) that provided 36 individual transmitter-receiver (TX-RX) combinations. For each of the 36 radio links, extensive directional measurements were made to give insights into small-cell base station diversity at millimeter-wave (mmWave) bands. High-gain steerable horn antennas with 7o and 15o half-power beamwidths (HPBW) were used at the transmitter (TX) and receiver (RX), respectively. For each TX-RX combination, the TX antenna was scanned over a 120o sector and the RX antenna was scanned over the entire azimuth plane at the strongest RX elevation plane and two other elevation planes on both sides of the strongest elevation angle, separated by the 15o HPBW. Directional and omnidirectional path loss models were derived and match well with the literature. Signal reception probabilities derived from the measurements for one to five base stations that served a single RX location show significant coverage improvement over all potential beamformed RX antenna pointing angles. CDFs for nearest neighbor and Best-N omnidirectional path loss and cell outage probabilities for directional antennas provide insights into coverage and interference for future mmWave small-cells that will exploit macro-diversity and CoMP.

Narrowband IoT Service Provision to 5G User Equipment via a Satellite Component

Abstract: Today an estimated 15 billion of connected objects communicate with each other''s. These connected objects that compose the Internet of Things (IoT) are expected to extend to 50 or 80 billion worldwide by 2020. Bringing wide-area connectivity for the IoT using satellite technology is therefore an attractive solution to complement terrestrial networks, allowing densification and coverage extension in remote areas. This paper deals with seamless integration of satellites and high altitude platforms (HAPS) into 5G networks. It describes the necessary modifications to operate on 5G systems in order to take satellite and HAPS specifics into account. Link budget calculations and system dimensioning, including channel modeling, are provided to determine the required satellite and HAPS performance as well as to estimate the number of served users per km².

Statistical prioritization for software product line testing: an experience report

Abstract: Software product lines (SPLs) are families of software systems sharing common assets and exhibiting variabilities specific to each product member of the family. Commonalities and variabilities are often represented as features organized in a feature model. Due to combinatorial explosion of the number of products induced by possible features combinations, exhaustive testing of SPLs is intractable. Therefore, sampling and prioritization techniques have been proposed to generate sorted lists of products based on coverage criteria or weights assigned to features. Solely based on the feature model, these techniques do not take into account behavioural usage of such products as a source of prioritization. In this paper, we assess the feasibility of integrating usage models into the testing process to derive statistical testing approaches for SPLs. Usage models are given as Markov chains, enabling prioritization of probable/rare behaviours. We used featured transition systems, compactly modelling variability and behaviour for SPLs, to determine which products are realizing prioritized behaviours. Statistical prioritization can achieve a significant reduction in the state space, and modelling efforts can be rewarded by better automation. In particular, we used MaTeLo, a statistical test cases generation suite developed at ALL4TEC. We assess feasibility criteria on two systems: Claroline, a configurable course management system, and Sferion™, an embedded system providing helicopter landing assistance.

Terahertz Time-Domain Spectroscopy System Driven by a Monolithic Semiconductor Laser

Abstract: A fiber coupled terahertz time-domain spectroscopy (THz TDS) system which is driven by a pulsed monolithic semiconductor laser is presented. A bandwidth of over 0.6 THz with a signal to noise ratio (SNR) of 45 dB has been achieved at a wavelength of 1550 nm. This concept could pave the way towards ultra-compact and low-cost THz TDS systems.

24 Tb/s unrepeatered C-band transmission of real-time processed 200 Gb/s PDM-16-QAM over 349 km

Abstract: We present a record unrepeatered experiment with 120 PDM-16-QAM channels at 200 Gb/s over 349.2 km, applying a high-power booster and a ROPA with third-order Raman pumping from the receiver end.

Base Station Diversity Propagation Measurements at 73 GHz Millimeter-Wave for 5G Coordinated Multipoint (CoMP) Analysis

Abstract: This paper describes wideband (1 GHz) base station diversity and coordinated multipoint (CoMP)-style large-scale measurements at 73 GHz in an urban microcell open square scenario in downtown Brooklyn, New York on the NYU campus. The measurements consisted of ten random receiver locations at pedestrian level (1.4 meters) and ten random transmitter locations at lamppost level (4.0 meters) that provided 36 individual transmitter-receiver (TX-RX) combinations. For each of the 36 radio links, extensive directional measurements were made to give insights into small-cell base station diversity at millimeter-wave (mmWave) bands. High-gain steerable horn antennas with 7-degree and 15-degree half-power beamwidths (HPBW) were used at the transmitter (TX) and receiver (RX), respectively. For each TX-RX combination, the TX antenna was scanned over a 120-degree sector and the RX antenna was scanned over the entire azimuth plane at the strongest RX elevation plane and two other elevation planes on both sides of the strongest elevation angle, separated by the 15-degree HPBW. Directional and omnidirectional path loss models were derived and match well with the literature. Signal reception probabilities derived from the measurements for one to five base stations that served a single RX location show significant coverage improvement over all potential beamformed RX antenna pointing angles. CDFs for nearest neighbor and Best-N omnidirectional path loss and cell outage probabilities for directional antennas provide insights into coverage and interference for future mmWave small-cells that will exploit macro-diversity and CoMP.

Power Allocation for Massive MIMO Cognitive Radio Networks with Pilot Sharing under SINR Requirements of Primary Users

Abstract: In this paper, we investigate the power allocation problem in massive multiple-input-multiple-output cognitive radio networks. We propose an orthogonal pilot sharing scheme at pilot transmission phase, where secondary users are allowed to use pilots for channel estimation only when there are temporarily unused orthogonal pilots. Following this, we formulate the power allocation optimization problem of the secondary network (SN) to maximize the downlink sum rate of the SN subject to the total transmit power and primary users' signal-interference-plus-noise-ratio constraints. Next, we transform the original (nonconvex) problem into a convex one by using convex approximation techniques and propose an iterative algorithm to obtain the solution. Furthermore, we prove that the proposed algorithm converges to Karush-Kuhn-Tucker points of the original problem. Meanwhile, the impact of the number of the secondary base station (SBS) antennas or the primary BS (PBS) antennas on the downlink rate of the SN and primary network is theoretically studied. Finally, the numerical results present the downlink sum rate of the SN under different parameters through our proposed algorithm.

A Highly Scalable IoT Architecture through Network Function Virtualization

Abstract: As the number of devices for Internet of Things (IoT) is rapidly growing, existing communication infrastructures are forced to continually evolve. The next generation network infrastructure is expected to be virtualized and able to integrate different kinds of information technology resources. Network Functions Virtualization (NFV) is one of the leading concepts facilitating the operation of network services in a scalable manner. In this paper, we present an architecture involving NFV to meet the requirements of highly scalable IoT scenarios. We highlight the benefits and challenges of our approach for IoT stakeholders. Finally, the paper illustrates our vision of how the proposed architecture can be applied in the context of a state-of-the-art high-tech operating room, which we are going to realize in future work.

Design of the high resolution optical instrument for the Pleiades HR Earth observation satellites

Abstract: As part of its contribution to Earth observation from space, ALCATEL SPACE designed, built and tested the High Resolution cameras for the European intelligence satellites HELIOS I and II. Through these programmes, ALCATEL SPACE enjoys an international reputation. Its capability and experience in High Resolution instrumentation is recognised by the most customers. Coming after the SPOT program, it was decided to go ahead with the PLEIADES HR program. PLEIADES HR is the optical high resolution component of a larger optical and radar multi-sensors system : ORFEO, which is developed in cooperation between France and Italy for dual Civilian and Defense use. ALCATEL SPACE has been entrusted by CNES with the development of the high resolution camera of the Earth observation satellites PLEIADES HR. The first optical satellite of the PLEIADES HR constellation will be launched in mid-2008, the second will follow in 2009. To minimize the development costs, a mini satellite approach has been selected, leading to a compact concept for the camera design. The paper describes the design and performance budgets of this novel high resolution and large field of view optical instrument with emphasis on the technological features. This new generation of camera represents a breakthrough in comparison with the previous SPOT cameras owing to a significant step in on-ground resolution, which approaches the capabilities of aerial photography. Recent advances in detector technology, optical fabrication and electronics make it possible for the PLEIADES HR camera to achieve their image quality performance goals while staying within weight and size restrictions normally considered suitable only for much lower performance systems. This camera design delivers superior performance using an innovative low power, low mass, scalable architecture, which provides a versatile approach for a variety of imaging requirements and allows for a wide number of possibilities of accommodation with a mini-satellite class platform.

Theoretical Evaluation and Experimental Validation of Localized Therapeutic Hypothermia Application to Preserve Residual Hearing After Cochlear Implantation.

Abstract: Objectives Cochlear implantation surgery has been shown to result in trauma to inner ear sensory structures, resulting in loss of residual hearing. Localized therapeutic hypothermia has been shown in clinical care to be a neuroprotective intervention. Previously, we have shown in an experimental model that localized hypothermia protects cochlear hair cells and residual hearing function against surgical and cochlear implantation trauma. Using experimental temperature measurements carried out in human cadaver temporal bones and a finite element model of the inner ear, the present study examined the temperature distribution of a custom-designed hypothermia delivery system in the human inner ear organs. Design The efficacy of the hypothermia probe and resulting heat distribution across human cochlea and surrounding tissues were modeled in three-dimensional in COMSOL. The geometry and dimensions of inner ear and temporal bones were derived from computed tomographic and magnetic resonance imaging images. Model predictions were compared with experimental observations from five human temporal bones. Results In both the modeling and experimental studies, the cochlear temperature was lowered by 4 to 6 °C on the round window from a baseline of 37 °C within 16 to 18 minutes. The model simulations showed uniformly distributed cooling across the cochlea. This study provides insight for design, operation, and protocols for efficacious delivery of mild therapeutic hypothermia to the human cochlea that may significantly benefit patients undergoing surgical cochlear implantation by preserving residual hearing. Conclusion There was a close correlation between the results of the numerical simulations and experimental observations in this study. Our custom-designed system is capable of effectively providing mild therapeutic hypothermia locally to the human cochlea. When combined with results from in vivo animal experiments, the present study suggests that the application of localized therapeutic hypothermia may hold potential for patients with an aim to preserve residual hearing after cochlear implantation.

PIANO: Proximity-Based User Authentication on Voice-Powered Internet-of-Things Devices

Abstract: Voice is envisioned to be a popular way for humans to interact with Internet-of-Things (IoT) devices. We propose a proximity-based user authentication method (called PIANO) for access control on such voice-powered IoT devices. PIANO leverages the built-in speaker, microphone, and Bluetooth that voice-powered IoT devices often already have. Specifically, we assume that a user carries a personal voice-powered device (e.g., smartphone, smartwatch, or smartglass), which serves as the user's identity. When another voice-powered IoT device of the user requires authentication, PIANO estimates the distance between the two devices by playing and detecting certain acoustic signals; PIANO grants access if the estimated distance is no larger than a user-selected threshold. We implemented a proof-of-concept prototype of PIANO. Through theoretical and empirical evaluations, we find that PIANO is secure, reliable, personalizable, and efficient.

Special cell selection at secondary network nodes supporting dual connectivity

Abstract: A computer program, network node and method performed at a secondary network node within a wireless communication network supporting dual connectivity, such that a user equipment may communicate with a master network node and a secondary network node at a same time, the secondary network node supporting a plurality of cells. The method comprising: determining at the secondary network node that a configuration of one of the plurality of cells as a special cell for the user equipment such that the special cell provides predetermined functionality should be transferred to another one of the plurality of cells; and in response to the determining step, transmitting a request for a change in special cell towards the master network node.

Enhancing the Utility of Anonymized Data by Improving the Quality of Generalization Hierarchies

Abstract: The dissemination of textual personal information has become an important driver of innovation. However, due to the possible content of sensitive information, this data must be anonymized. A commonly-used technique to anonymize data is generalization. Nevertheless, its effectiveness can be hampered by the Value Generalization Hierarchies (VGHs) used as poorly-specified VGHs can decrease the usefulness of the resulting data. To tackle this problem, in our previous work we presented the Generalization Semantic Loss (GSL), a metric that captures the quality of categorical VGHs in terms of semantic consistency and taxonomic organization. We validated the accuracy of GSL using an intrinsic evaluation with respect to a gold standard ontology. In this paper, we extend our previous work by conducting an extrinsic evaluation of GSL with respect to the performance that VGHs have in anonymization (using data utility metrics). We show how GSL can be used to perform an a priori assessment of the VGHs' effectiveness for anonymization. In this manner, data publishers can quantitatively compare the quality of various VGHs and identify (before anonymization) those that better retain the semantics of the original data. Consequently, the utility of the anonymized datasets can be improved without sacrificing the privacy goal. Our results demonstrate the accuracy of GSL, as the quality of VGHs measured with GSL strongly correlates with the utility of the anonymized data. Results also show the benefits that an a priori VGH assessment strategy brings to the anonymization process in terms of time-savings and a reduction in the dependency on expert knowledge. Finally, GSL also proved to be lightweight in terms of computational resources.

40-Gb/s TDM-PON Downstream Link With Low-Cost EML Transmitter and APD-Based Electrical Duobinary Receiver

Abstract: We report a cost-effective 40-Gb/s time-division multiplexing passive optical network downstream link using three-level electrical duobinary modulation. The transmitter consists of a compact electroabsorption-modulated laser module. The receiver contains an avalanche photodiode packaged with a transimpedance amplifier, with digitally adjustable gain and bandwidth, followed by a duobinary decoder. Real-time eye diagram and bit-error rate (BER) measurements were performed. At a preforward error correction BER of $10^{-3}$ , a power budget of 23.6 dB in back-to-back conditions is demonstrated. For a dispersion range of −215 to 128 ps/nm, the power penalty does not exceed 3 dB.

Providing data plane services for applications

Abstract: The present disclosure generally discloses a data plane services support mechanism. The data plane services support mechanism may be configured to provide a data plane service for an application. The data plane services support mechanism may be configured to instantiate a virtual resource for the data plane service to be provided for the application, configure the data plane service on the virtual resource, and configure flow connectivity for the data plane service to support delivery of application traffic of the application to the data plane service. The data plane services support mechanism may be configured to support automatic scalability. The data plane services support mechanism may be configured to support improved communication of application traffic associated with providing the data plane service for the application. The improved communication of application traffic may be provided based on configuration of a virtual switch to support a network interface card (NIC) offloading capability.

Coexistence of 5G mmWave Users with Incumbent Fixed Stations over 70 and 80 GHz

Abstract: Millimeter wave spectrum access over the 70GHz and 80GHz is central to unlocking gigabit connectivity and meeting the explosive growth of mobile traffic. A pressing question, however, is whether fifth-generation (5G) systems can harmoniously coexist with the incumbents of these bands, which are primarily point-to-point fixed stations (FSs). To this end, we thoroughly analyze the impact of 5G coexistence on FSs. Specifically, we first analyze the geometry of existing FSs' deployment using actual databases of these stations. Then, we present a case study on the interference generated from users towards FSs in two populated areas in Chicago, where we use actual building databases to accurately compute the aggregate interference. The analysis and simulation results reveal that the deployment strategy of FSs and the high attenuation losses at 70/80GHz significantly limit the 5G interference, with the majority of FSs experiencing interference levels well below the noise floor.

Layer 2 Relay To Support Coverage And Resource-Constrained Devices In Wireless Networks

Abstract: Embodiments provide a mobile communications device that includes a processor configured to communicate with a transceiver and a memory. The transceiver is configured to exchange control signals with a network node. The memory contains instructions that when executed by the processor configure the processor to operate the transceiver to exchange the control signals. The instructions further configure the processor to pass a first proper subset of the control signals to a remote device without operating according to the control signals, and to operate according to control signals in a second proper subset of the control signals. The processor is thereby configured to operate on behalf of a remote communication device to support communication between the remote communication device and the network node.

On-Demand Power Boost and Cell Muting for High Reliability and Low Latency in 5G

Abstract: 5G downlink Inter-Cell Interference Coordination (ICIC) has a twofold objective: to better exploit the benefits of ICIC in coherence with the rest of Radio Resource Management (RRM) principles in 5G; and to support new 5G service classes and their coexistence in a multi-service setting. We propose on-demand Power Boosting and Inter-cell Coordination (PB-IC) to meet high reliability and low latency requirements of critical data without compromising the spectral efficiency of the rest of traffic. PB-IC is demostrated to provide similar latency gains as the classical frequency reuse, but much lower impact to the enhanced Mobile BroadBand (eMBB) traffic. Results demonstrate that the tail of the latency distribution is reduced as much as 100% in the 10^-4 percentile, achieving comparable gains to static frequency reuse. At the same time, the degradation in eMBB throughput is minimized, reaching a 14% loss instead of the 50% observed with static ICIC. We discuss the standardization effort required for having PB-IC supported, with considerations of the measurement requirements to the UE and the infrastructure backhaul latencies.

Low-frequency electromagnetic tracking

Abstract: A medical system tracks the position of a medical instrument within a body of a patient The medical instrument includes an electromagnet structure having an inductor coil wound around a core A control circuit applies a low frequency excitation signal across the inductor coil The inductor coil and the core generate a magnetic field A plurality of sensors sense parameters of the generated magnetic field and produce sensor signals The control circuit calculates the position of the medical instrument based on the produced sensor signals

A 5G Lightweight Connectionless Protocol for Massive Cellular Internet of Things

Abstract: We present a novel protocol for massive cellular Internet of Things (IoT) based on the connectionless access approach. Our solution has very low signaling overhead and is thus very efficient for sporadic short burst traffic applications. Numerical analysis of the capacity achieved by our solution indicates that millions of (IoT) devices can be served with a 10 MHz system bandwidth. Furthermore, our proposal shows capacity gains of up to 260% when compared against state-of-the-art solutions such as legacy LTE, eMTC and NB-IoT.

System and method for controlling network traffic by restricting a set of cyclic shifts for long-term evolution (LTE) physical random access channel (PRACH) preambles

Abstract: The controlling of the network traffic is implemented in a communication network by obtaining first configuration parameters for physical random access channel (PRACH) preambles, the first configuration parameters including a first preamble format, a zero correlation zone configuration index, and a list of physical root Zadoff-Chu sequence indexes. A set of cyclic shifts corresponding to a first frequency offset is generated based on the first preamble format, the zero correlation zone configuration index, and the list of physical root Zadoff-Chu sequence indexes. Second configuration parameters are exported in order to control network traffic, the second configuration parameters including the set of cyclic shifts.

Data plane for processing function scalability

Abstract: The present disclosure generally discloses a data plane configured for processing function scalability. The processing functions for which scalability is supported may include charging functions, monitoring functions, security functions, or the like.

Near Capacity 24.6 Tb/s Transmission over 10,285km Straight Line Testbed at 5.9 b/s/Hz Spectral Efficiency Using TPCS-64QAM and C-Band EDFA-Only

Abstract: We report on a C-band 10,285 km straight line testbed transmission using capacity-approaching truncated probabilistic constellation shaping 64QAM (TPCS-64QAM). Seven FEC code rates allow 24.6 Tb/s transpacific transmission with spectral efficiency of 5.9 bit/s/Hz.