Showing papers by "Alcatel-Lucent published in 2011"

How much energy is needed to run a wireless network

Abstract: In order to quantify the energy efficiency of a wireless network, the power consumption of the entire system needs to be captured. In this article, the necessary extensions with respect to existing performance evaluation frameworks are discussed. The most important addenda of the proposed energy efficiency evaluation framework (E3F) are a sophisticated power model for various base station types, as well as large-scale long-term traffic models. The BS power model maps the RF output power radiated at the antenna elements to the total supply power of a BS site. The proposed traffic model emulates the spatial distribution of the traffic demands over large geographical regions, including urban and rural areas, as well as temporal variations between peak and off-peak hours. Finally, the E3F is applied to quantify the energy efficiency of the downlink of a 3GPP LTE radio access network.

Understanding traffic dynamics in cellular data networks

Abstract: We conduct the first detailed measurement analysis of network resource usage and subscriber behavior using a large-scale data set collected inside a nationwide 3G cellular data network. The data set tracks close to a million subscribers over thousands of base stations. We analyze individual subscriber behaviors and observe a significant variation in network usage among subscribers. We characterize subscriber mobility and temporal activity patterns and identify their relation to traffic volume. We then investigate how efficiently radio resources are used by different subscribers as well as by different applications. We also analyze the network traffic from the point of view of the base stations and find significant temporal and spatial variations in different parts of the network, while the aggregated behavior appears predictable. Broadly, our observations deliver important insights into network-wide resource usage. We describe implications in pricing, protocol design and resource and spectrum management.

SLEEP mode techniques for small cell deployments

Abstract: Big things come in small packages; a particularly apt description of small cell deployment in cellular networks. Small cells have a big role to play in orchestrating a cellular network that can overcome the explosive mobile traffic upsurge at little cost to the network operator. However, if left unchecked, a large-scale small cell deployment can substantially increase the network energy consumption with strong ecological and economic implications. In this article, we introduce energy-efficient SLEEP mode algorithms for small cell base stations in a bid to reduce cellular networks' power consumption. The designed algorithms allow the hardware components in the BS to be astutely switched off in idle conditions, such that the energy consumption is modulated over the variations in traffic load. Three different strategies for algorithm control are discussed, relying on small cell driven, core network driven, and user equipment driven approaches. Based on a mixed voice and data traffic model, the algorithms present energy saving opportunities of approximately 10-60 percent in the network with respect to no SLEEP mode activation in small cells, coupled with additional capacity incentives.

Item popularity and recommendation accuracy

Abstract: Recommendations from the long tail of the popularity distribution of items are generally considered to be particularly valuable. On the other hand, recommendation accuracy tends to decrease towards the long tail. In this paper, we quantitatively examine this trade-off between item popularity and recommendation accuracy. To this end, we assume that there is a selection bias towards popular items in the available data. This allows us to define a new accuracy measure that can be gradually tuned towards the long tail. We show that, under this assumption, this measure has the desirable property of providing nearly unbiased estimates concerning recommendation accuracy. In turn, this also motivates a refinement for training collaborative-filtering approaches. In various experiments with real-world data, including a user study, empirical evidence suggests that only a small, if any, bias of the recommendations towards less popular items is appreciated by users.

Apnea MedAssist: Real-time Sleep Apnea Monitor Using Single-Lead ECG

Abstract: We have developed a low-cost, real-time sleep apnea monitoring system ``Apnea MedAssist” for recognizing obstructive sleep apnea episodes with a high degree of accuracy for both home and clinical care applications. The fully automated system uses patient's single channel nocturnal ECG to extract feature sets, and uses the support vector classifier (SVC) to detect apnea episodes. “Apnea MedAssist” is implemented on Android operating system (OS) based smartphones, uses either the general adult subject-independent SVC model or subject-dependent SVC model, and achieves a classification F-measure of 90% and a sensitivity of 96% for the subject-independent SVC. The real-time capability comes from the use of 1-min segments of ECG epochs for feature extraction and classification. The reduced complexity of “Apnea MedAssist” comes from efficient optimization of the ECG processing, and use of techniques to reduce SVC model complexity by reducing the dimension of feature set from ECG and ECG-derived respiration signals and by reducing the number of support vectors.

Massive MIMO: How many antennas do we need?

Abstract: We consider a multicell MIMO uplink channel where each base station (BS) is equipped with a large number of antennas N. The BSs are assumed to estimate their channels based on pilot sequences sent by the user terminals (UTs). Recent work has shown that, as N grows infinitely large, (i) the simplest form of user detection, i.e., the matched filter (MF), becomes optimal, (ii) the transmit power per UT can be made arbitrarily small, (iii) the system performance is limited by pilot contamination. The aim of this paper is to assess to which extent the above conclusions hold true for large, but finite N. In particular, we derive how many antennas per UT are needed to achieve \eta % of the ultimate performance. We then study how much can be gained through more sophisticated minimum-mean-square-error (MMSE) detection and how many more antennas are needed with the MF to achieve the same performance. Our analysis relies on novel results from random matrix theory which allow us to derive tight approximations of achievable rates with a class of linear receivers.

Massive MIMO: How many antennas do we need?

Abstract: We consider a multicell MIMO uplink channel where each base station (BS) is equipped with a large number of antennas N. The BSs are assumed to estimate their channels based on pilot sequences sent by the user terminals (UTs). Recent work has shown that, as N → ∞, (i) the simplest form of user detection, i.e., the matched filter (MF), becomes optimal, (ii) the transmit power per UT can be made arbitrarily small, (iii) the system performance is limited by pilot contamination. The aim of this paper is to assess to which extent the above conclusions hold true for large, but finite N. In particular, we derive how many antennas per UT are needed to achieve η % of the ultimate performance. We then study how much can be gained through more sophisticated minimum-mean-square-error (MMSE) detection and how many more antennas are needed with the MF to achieve the same performance. Our analysis relies on novel results from random matrix theory which allow us to derive tight approximations of achievable rates with a class of linear receivers.

Interference Assisted Secret Communication

Abstract: Wireless communication is susceptible to eavesdropping attacks because of its broadcast nature. This paper illustrates how interference can be used to counter eavesdropping and assist secrecy. In particular, a wiretap channel with a helping interferer (WT-HI) is considered. Here, a transmitter sends a confidential message to its intended receiver in the presence of a passive eavesdropper and with the help of an independent interferer. The interferer, which does not know the confidential message, helps in ensuring the secrecy of the message by sending an independent signal. An achievable secrecy rate and several computable outer bounds on the secrecy capacity of the WT-HI are given for both discrete memoryless and Gaussian channels.

System and method of wireless communication using large-scale antenna networks

Abstract: A communication method uses a distributed cell-free network of spatially independent service antennas. According to the method, pilot sequences are allocated to a user population of access terminals by an allocation procedure that imposes local relative orthogonality of pilot sequences. Channel coefficients for access terminals are determined by measuring allocated pilot sequences as received by each of the service antennas. In embodiments of the invention, the determination of channel coefficients is performed independently and the resulting channel coefficients are locally stored at the respective service antennas. At each service antenna, a processor independently uses locally stored channel coefficients to precode forward link signals or to at least partially decode reverse link signals.

Policy routing-based lawful interception in communication system with end-to-end encryption

Abstract: Techniques are disclosed for lawfully intercepting information in communication environments with end-to-end encryption. For example, a method for intercepting encrypted communications exchanged between a first computing device and a second computing device in a communication network, wherein the interception is performed by a third computing device in the communication network, comprises the following steps. The third computing device obtains one or more packets having a packet address associated with one of the first computing device and the second computing device. The one or more packets are obtained by the third computing device, in response to at least one interception routing policy being implemented in at least one element in the communication network, such that the one or more obtained packets may be decrypted so as to obtain data contained therein. The third computing device preserves the packet address of the one or more obtained packets. The third computing device forwards the one or more packets toward a packet- destination one of the first computing device and the second computing device such that the packet-destination one of the first computing device and the second computing device is unable to detect from the one or more packets that the one or more packets were intercepted by the third computing device.

Method and apparatus of smart power management for mobile communication terminals using power thresholds

Abstract: A method is provided for use in a mobile communication terminal configured to support a plurality of applications, wherein each application is executed by performing one or more tasks. The method includes, in response to a scheduling request from an application, obtaining an indication of power supply condition at a requested run-time of at least one of the tasks. The method further includes obtaining a prediction of a rate of energy usage by the task at the requested run-time, estimating, from the predicted rate of energy usage, a total amount of energy needed to complete the task, and making a scheduling decision for the task. The scheduling decision comprises making a selection from a group of two or more alternative dispositions for the task. The selection is made according to a criterion that relates the run-time power-supply condition to the predicted rate of energy usage by the task and to the estimate of total energy needed to complete the task.

Control Over Imperfect Networks: Model-Based Predictive Networked Control Systems

Abstract: Networked control systems (NCSs) are digital control systems in which the functionality of the sensor, control, and actuator reside in physically different computer nodes communicating over a network. However, random delays and data loss of the communication network can endanger the stability of an NCS. We have proposed model-based predictive NCSs (MBPNCSs) that compensate for the aforementioned problems and avoid performance loss using a predictive control scheme based on a model of the plant. There are three main contributions of this paper to existing methods: an NCS that can work under random network delay and data loss with realistic structural assumptions, an explicit mechanism for reducing the effects of network delay and data loss on the deviation of plant state estimates from actual plant states, and an architecture where upstream nodes can work without receiving acknowledge information about the status of previously sent data packets from downstream nodes. In this paper, we describe MBPNCS and then introduce a stability criterion. This is followed by computer simulations and experiments involving the speed control of a dc motor. The results show that considerable improvement over performance is achieved with respect to an event-based NCS.

Models for Planning Capacity Expansion in Local Access Telecommunication Networks

Abstract: The rapid progress of communications technology has created new opportunities for modeling and optimizing the design of local telecommunication systems. The complexity, diversity, and continuous evolution of these networks pose several modeling challenges. In this paper, we present an overview of the local telephone network environment, and discuss possible modeling approaches. In particular, we (i) discuss the engineering characteristics of the network, and introduce terminology that is commonly used in the communications industry and literature; (ii) describe a general local access network planning model and framework, and motivate different possible modeling assumptions; (iii) summarize various existing planning models in the context of this framework; and (iv) describe some new modeling approaches. The discussion in this paper is directed both to researchers interested in modeling local telecommunications systems and to planners interested in using such models. Our goal is to present relevant aspects of the engineering environment for local access telecommunication networks, and to discuss the relationship between engineering issues and the formulation of economic decision models. We indicate how changes in the underlying switching and transmission technology affect the modeling of the local telephone network. We also review various planning issues and discuss possible optimization approaches for treating them.

Message-passing estimation from quantized samples

Abstract: Estimation of a vector from quantized linear measurements is a common problem for which simple linear techniques are suboptimal -- sometimes greatly so This paper develops generalized approximate message passing (GAMP) algorithms for minimum mean-squared error estimation of a random vector from quantized linear measurements, notably allowing the linear expansion to be overcomplete or undercomplete and the scalar quantization to be regular or non-regular GAMP is a recently-developed class of algorithms that uses Gaussian approximations in belief propagation and allows arbitrary separable input and output channels Scalar quantization of measurements is incorporated into the output channel formalism, leading to the first tractable and effective method for high-dimensional estimation problems involving non-regular scalar quantization Non-regular quantization is empirically demonstrated to greatly improve rate-distortion performance in some problems with oversampling or with undersampling combined with a sparsity-inducing prior Under the assumption of a Gaussian measurement matrix with iid entries, the asymptotic error performance of GAMP can be accurately predicted and tracked through the state evolution formalism We additionally use state evolution to design MSE-optimal scalar quantizers for GAMP signal reconstruction and empirically demonstrate the superior error performance of the resulting quantizers

Virtual IP interfaces on multi-chassis link aggregates

Abstract: Aggregation Switches connected via a virtual fabric link (VFL) are each active and each coupled to a multi-chassis link aggregate group (MC-LAG), which is assigned to a multi-chassis link aggregate group virtual local area network (MC-LAG VLAN). A virtual Internet Protocol (IP) interface is allocated to the MC-LAG VLAN and configured on both Aggregation Switches.

Coalition Formation Games for Collaborative Spectrum Sensing

Abstract: Collaborative spectrum sensing (CSS) between secondary users (SUs) in cognitive networks exhibits an inherent tradeoff between minimizing the probability of missing the detection of the primary user (PU) and maintaining a reasonable false alarm probability (e.g., for maintaining good spectrum utilization). In this paper, we study the impact of this tradeoff on the network structure and the cooperative incentives of the SUs that seek to cooperate to improve their detection performance. We model the CSS problem as a nontransferable coalitional game, and we propose distributed algorithms for coalition formation (CF). First, we construct a distributed CF algorithm that allows the SUs to self-organize into disjoint coalitions while accounting for the CSS tradeoff. Then, the CF algorithm is complemented with a coalitional voting game to enable distributed CF with detection probability (CF-PD) guarantees when required by the PU. The CF-PD algorithm allows the SUs to form minimal winning coalitions (MWCs), i.e., coalitions that achieve the target detection probability with minimal costs. For both algorithms, we study and prove various properties pertaining to network structure, adaptation to mobility, and stability. Simulation results show that CF reduces the average probability of miss per SU up to 88.45%, relative to the noncooperative case, while maintaining a desired false alarm. For CF-PD, the results show that up to 87.25% of the SUs achieve the required detection probability through MWCs.

InAs/InP Quantum-Dot Passively Mode-Locked Lasers for 1.55-μ m Applications

Abstract: This paper reports on recent results on passively mode-locked InAs/InP quantum-dot-based lasers. These low-dimensional structures have proved very attractive in improving most of the properties of these devices. Subpicosecond pulse generation at repetition rates up to beyond 300 GHz has readily been demonstrated. Ultranarrow RF linewidths reach record values of less than 1 kHz. Controlled optical feedback allows a further reduction of this linewidth yielding extremely low timing jitter. A comparison of single-section and standard two-section lasers is given for the first time. These performances open the way to various applications at 1.55 μm, including very high bit rate all-optical signal processing, frequency comb generation, radio over fiber, and low-noise all-optical oscillators.

Channel Estimation and Linear Precoding in Multiuser Multiple-Antenna TDD Systems

Abstract: Traditional approaches in the analysis of downlink systems decouple the precoding and the channel estimation problems. However, in cellular systems with mobile users, these two problems are, in fact, tightly coupled. In this paper, this coupling is explicitly studied by accounting for the channel training overhead and estimation error while determining the overall system throughput. This paper studies the problem of utilizing imperfect channel estimates for efficient linear precoding and user selection. It presents precoding methods that take into account the degree of channel estimation error. Information-theoretic lower and upper bounds are derived to evaluate the performance of these precoding methods. In typical scenarios, these bounds are close.

Cross-Domain Privacy Management Service For Social Networking Sites

Abstract: A cross-domain privacy management service for social networking sites is implemented in a communication system including a user platform operably connected to an application platform. The application platform accesses one or more social networking sites on behalf of a user to obtain indicia of privacy settings of the user and displays the privacy settings via a graphical user interface accessible to the user independent of the social networking sites. The user may interact with graphical icons via the graphical user interface to change privacy settings of one or more impacted sites, and the user changes are communicated to the social networking sites via the application platform on behalf of the user.

On the design of content-centric MANETs

Abstract: Content-centric networking focuses on data delivery rather than end-to-end reachability by decoupling resources from the hosts they reside on. We consider content-centric networking as a fundamental driver for mobile ad hoc network (MANET) protocol design. We systematically evaluate the suitability and effectiveness of existing approaches toward designing a content-centric MANET. We leverage the extensive prior work on both resource discovery and routing. To examine and compare the various existing designs, we identify a set of representative design alternatives. We develop analytical models for these designs that evaluate their efficiency for a content-centric MANET. Our models provide insights into the strengths and weaknesses of candidate design choices. Our analysis explores the performance boundaries of MANET designs and yields surprising results comparing unstructured flooding to more complex structured solutions. Based on our results, we derive a set of recommendations that are key to the successful design of a content-centric MANET.

Method and apparatus for MPLS label allocation for a BGP MAC-VPN

Abstract: The invention includes a method and apparatus for distributing flooding labels within a Multiprotocol Label Switching (MPLS) infrastructure supporting Border Gateway Protocol (BGP) Media Access Control (MAC) Virtual Private Networking (VPN),

Effects of the Generation Size and Overlap on Throughput and Complexity in Randomized Linear Network Coding

Abstract: To reduce computational complexity and delay in randomized network coded content distribution, and for some other practical reasons, coding is not performed simultaneously over all content blocks, but over much smaller, possibly overlapping subsets of these blocks, known as generations. A penalty of this strategy is throughput reduction. To analyze the throughput loss, we model coding over generations with random generation scheduling as a coupon collector's brotherhood problem. This model enables us to derive the expected number of coded packets needed for successful decoding of the entire content as well as the probability of decoding failure (the latter only when generations do not overlap) and further, to quantify the tradeoff between computational complexity and throughput. Interestingly, with a moderate increase in the generation size, throughput quickly approaches link capacity. Overlaps between generations can further improve throughput substantially for relatively small generation sizes.

Ip multicast snooping and routing with multi-chassis link aggregation

Abstract: Aggregation Switches connected via a virtual fabric link (VFL) (124) are each active and able to perform at least limited IP multicast snooping. The resulting IP multicast snooping information is maintained internally within each Aggregation Switch (106a, 106b) and shared substantially in real-time therebetween via the VFL (124).

Scalable Video Multicast in Hybrid 3G/Ad-Hoc Networks

Abstract: Mobile video broadcasting service, or mobile TV, is expected to become a popular application for 3G wireless network operators. Most existing solutions for video Broadcast Multicast Services (BCMCS) in 3G networks employ a single transmission rate to cover all viewers. The system-wide video quality of the cell is therefore throttled by a few viewers close to the boundary, and is far from reaching the social-optimum allowed by the radio resources available at the base station. In this paper, we propose a novel scalable video broadcast/multicast solution, SV-BCMCS, that efficiently integrates scalable video coding, 3G broadcast, and ad-hoc forwarding to balance the system-wide and worst-case video quality of all viewers at 3G cell. We solve the optimal resource allocation problem in SV-BCMCS and develop practical helper discovery and relay routing algorithms. Moreover, we analytically study the gain of using ad-hoc relay, in terms of users' effective distance to the base station. Through extensive real video sequence driven simulations, we show that SV-BCMCS significantly improves the system-wide perceived video quality. The users' average PSNR increases by as much as 1.70 dB with slight quality degradation for the few users close to the 3G cell boundary.

Method and apparatus for interference cancellation for antenna arrays

Abstract: Embodiments of the claimed subject matter provide methods and apparatuses for interference cancellation. One embodiment of a method includes estimating, for an antenna in an antenna array including a plurality of antennas, interference parameters using analog signals received at the antenna on each of a plurality of subcarriers. Each interference parameter is associated with one of a plurality of symbols transmitted to one of a plurality of users on one of the plurality of subcarriers. This embodiment also includes canceling interference from analog signals received by the antenna on the plurality of subcarriers using the estimated interference parameters.

Enabling predictive web browsing

Abstract: A system and method for determining and displaying, in a predictive manner, relevant "next clicks" based upon historical web-usage patterns of previous visitors (the browsing user and/or other users) to referring web pages. In one embodiment, identification of one or more links selected by previous visitors on a plurality of referring web pages is stored in a database. When the browsing user initiates a request to view a referring web page for which one or more links exist in the database, the appearance of those links on the referring web page is altered to suggest those links to the browsing user. Thus, the browsing user is given suggestions as to the most probable path (based upon his/her own history and/or the history of others) through each referring web page for which one or more links are stored in the database, thereby streamlining the browsing process.

Optimized Fairness Cell Selection for 3GPP LTE-A Macro-Pico HetNets

Abstract: Pico cell has been brought to cellular networks as a new technology to deliver cost-effective coverage and capacity to hard-to-reach places, and also increase capacity by cell splitting in hotspots with very dense phone usage. However, according to existing strongest receiving signal association method, pico cells with the extremely low transmitting power are significantly limited in the presence of macro coverage. Thus, the new introduced pico frequency resource will not be fully exploited in this unbalanced user distributions among macro and pico cells. In this paper, by jointly considering the long term channel condition and load balance in this macro-pico coexisted heterogeneous network, we formulate the cell selection problem into a network-wide proportional fairness optimization. Both optimal solution (by dynamic programming) and cost efficient algorithm (greedy heuristics) are proposed. In 3GPP LTE-A heterogeneous network scenario, the system-level performance evaluation shows that, compared with the conventional strongest signal cell selection scheme, the proposed optimized fairness cell selection methods could achieve significant performance gains especially for the cell edge users.

Alerts for drivers of wireless communication restrictions

Abstract: An exemplary method provides for a wireless mobile unit an alert representing a warning that legally imposed restrictions on the use of wireless mobile units by drivers of moving vehicles in predetermined zones. The method includes determining by a communication system if a first mobile unit is being used for wireless communications, and acquiring by the communication system the location of the first mobile unit. The communication system compares the location of the first mobile unit to locations of the predetermined zones having restrictions on the use of wireless mobile units by drivers of moving vehicles. Upon the first mobile unit entering a warning zone that is adjacent the predetermined zone and the first mobile unit being used for wireless communications, the transmission of an alert is initiated to the first mobile unit. The alert causes the first mobile unit to output an audible or visual communication available to the user of the first mobile unit, where the audible or visual communication provides a warning that a legally imposed restriction on the use of the first wireless mobile unit by a driver of moving vehicle is imposed in the predetermined zone.