Showing papers by "Huawei published in 2012"

ThinkAir: Dynamic resource allocation and parallel execution in the cloud for mobile code offloading

Abstract: Smartphones have exploded in popularity in recent years, becoming ever more sophisticated and capable. As a result, developers worldwide are building increasingly complex applications that require ever increasing amounts of computational power and energy. In this paper we propose ThinkAir, a framework that makes it simple for developers to migrate their smartphone applications to the cloud. ThinkAir exploits the concept of smartphone virtualization in the cloud and provides method-level computation offloading. Advancing on previous work, it focuses on the elasticity and scalability of the cloud and enhances the power of mobile cloud computing by parallelizing method execution using multiple virtual machine (VM) images. We implement ThinkAir and evaluate it with a range of benchmarks starting from simple micro-benchmarks to more complex applications. First, we show that the execution time and energy consumption decrease two orders of magnitude for a N-queens puzzle application and one order of magnitude for a face detection and a virus scan application. We then show that a parallelizable application can invoke multiple VMs to execute in the cloud in a seamless and on-demand manner such as to achieve greater reduction on execution time and energy consumption. We finally use a memory-hungry image combiner tool to demonstrate that applications can dynamically request VMs with more computational power in order to meet their computational requirements.

Coordinated multipoint transmission and reception in LTE-advanced: deployment scenarios and operational challenges

Abstract: 3GPP has completed a study on coordinated multipoint transmission and reception techniques to facilitate cooperative communications across multiple transmission and reception points (e.g., cells) for the LTE-Advanced system. In CoMP operation, multiple points coordinate with each other in such a way that the transmission signals from/to other points do not incur serious interference or even can be exploited as a meaningful signal. The goal of the study is to evaluate the potential performance benefits of CoMP techniques and the implementation aspects including the complexity of the standards support for CoMP. This article discusses some of the deployment scenarios in which CoMP techniques will likely be most beneficial and provides an overview of CoMP schemes that might be supported in LTE-Advanced given the modern silicon/DSP technologies and backhaul designs available today. In addition, practical implementation and operational challenges are discussed. We also assess the performance benefits of CoMP in these deployment scenarios with traffic varying from low to high load.

Design and implementation of a consolidated middlebox architecture

Abstract: Network deployments handle changing application, workload, and policy requirements via the deployment of specialized network appliances or "middleboxes". Today, however, middlebox platforms are expensive and closed systems, with little or no hooks for extensibility. Furthermore, they are acquired from independent vendors and deployed as standalone devices with little cohesiveness in how the ensemble of middleboxes is managed. As network requirements continue to grow in both scale and variety, this bottom-up approach puts middlebox deployments on a trajectory of growing device sprawl with corresponding escalation in capital and management costs. To address this challenge, we present CoMb, a new architecture for middlebox deployments that systematically explores opportunities for consolidation, both at the level of building individual middleboxes and in managing a network of middleboxes. This paper addresses key resource management and implementation challenges that arise in exploiting the benefits of consolidation in middlebox deployments. Using a prototype implementation in Click, we show that CoMb reduces the network provisioning cost 1.8-2.5× and reduces the load imbalance in a network by 2-25×.

Evolved multimedia broadcast/multicast service (eMBMS) in LTE-advanced: overview and Rel-11 enhancements

Abstract: The Third Generation Partnership Project defined multimedia broadcast/multicast service in 2005 to optimize the distribution of video traffic. This standard covers the terminal, radio, core network, and user service aspects. This MBMS standard has evolved into enhanced MBMS (eMBMS) that builds on top of the 3GPP Long Term Evolution standard. eMBMS evolution brings improved performance thanks to higher and more flexible LTE bit rates, single frequency network operations, and carrier configuration flexibility. 3GPP Rel-11 also brings improvements in the areas of service layer with, for example, video codec for higher resolutions and frame rate, and forward error correction. eMBMS allows offloading of the LTE network and backhaul. It enables the possibility to deliver premium content to many users with secured quality of service in defined areas. Other important use cases are pushed content via user equipment caching and machine-to-machine services. This article describes the relevant use cases for eMBMS in terms of service. It then gives a tutorial on eMBMS, in particular highlighting the evolution over MBMS. The scope comprises the radio access, core network, and service layer.

An Adaptive Successive Cancellation List Decoder for Polar Codes with Cyclic Redundancy Check

Abstract: In this letter, we propose an adaptive SC (Successive Cancellation)-List decoder for polar codes with CRC. This adaptive SC-List decoder iteratively increases the list size until at least one survival path can pass CRC. Simulation shows that the adaptive SC-List decoder provides significant complexity reduction. We also demonstrate that polar code (2048, 1024) with 24-bit CRC decoded by our proposed adaptive SC-List decoder with very large maximum list size can achieve a frame error rate FER ≤ 10-3{-3} at Eb/No = 1.1dB, which is about 0.25dB from the information theoretic limit at this block length.

Coordinated multipoint transmission and reception in LTE-advanced systems

Abstract: Advanced interference mitigation techniques relying on multipoint coordination have attracted significant attention from the wireless industry and academia in the past few years. In 3GPP LTE-Advanced, a work item on Coordinated Multiple Point transmission and reception (CoMP) was initiated in September 2011, and it is one of the core features of Release 11. The objective of this work item is to provide the necessary specification support to efficiently realize the benefits of cooperative transmission in the downlink and cooperative reception in the uplink. This article discusses the specification support for CoMP and the motivations behind the specific design choices. The deployment scenarios that were considered for the application of CoMP in Release 11 are also presented.

Downlink MIMO in LTE-advanced: SU-MIMO vs. MU-MIMO

Abstract: Single-user multi-antenna technologies are well upported in current standard specifications like LTE Release 8/9. Further development of the specification (LTE-Advanced) is expected to conform to the requirements for IMT-Advanced systems. One of the key enabling features of LTE-Advanced to meet IMT-Advanced downlink performance requirements is multi-user MIMO, where a transmitter serves multiple users simultaneously on the same frequency resource, primarily relying on spatial separation. In general, multi-user MIMO is beneficial for improving average user spectral efficiency. However, cell edge user spectral efficiency may be reduced if multi-user MIMO is used exclusively, due to residual inter-user interference arising from practical multi-user beamforming and reduced transmit power allocated to each user. Therefore, it should be possible to configure the UE-specific transmission mode to support dynamic switching between single-user MIMO and multi-user MIMO to balance the cell edge user spectral efficiency as well as the average cell user spectral efficiency. In this article, we study various aspects of multi-user MIMO including design philosophy, multi-user precoding, and control signaling. The associated feedback schemes, including those that facilitate dynamic switching, are discussed. Performance evaluation is conducted to demonstrate the gain of dynamically switched single-user and multiuser MIMO as opposed to traditional single-user MIMO.

An Adaptive Successive Cancellation List Decoder for Polar Codes with Cyclic Redundancy Check

Abstract: In this letter, we propose an adaptive SC (Successive Cancellation)-List decoder for polar codes with CRC. This adaptive SC-List decoder iteratively increases the list size until the decoder outputs contain at least one survival path which can pass CRC. Simulation shows that the adaptive SC-List decoder provides significant complexity reduction. We also demonstrate that polar code (2048, 1024) with 24-bit CRC decoded by our proposed adaptive SC-List decoder with very large list size can achieve a frame error rate FER=0.001 at Eb/No=1.1dB, which is about 0.2dB from the information theoretic limit at this block length.

Band-Limited Volterra Series-Based Digital Predistortion for Wideband RF Power Amplifiers

Abstract: The continuously increasing demand for wide bandwidth creates great difficulties in employing digital predistortion (DPD) for radio frequency (RF) power amplifiers (PAs) in future ultra-wideband systems because the existing DPD system requires multiple times the input signal bandwidth in the transmitter and receiver chain, which is sometimes almost impossible to implement in practice. In this paper, we present a novel band-limited digital predistortion technique in which a band-limiting function is inserted into the general Volterra operators in the DPD model to control the signal bandwidth under modeling, which logically transforms the general Volterra series-based model into a band-limited version. This new approach eliminates the system bandwidth constraints of the conventional DPD techniques, and it allows users to arbitrarily choose the bandwidth to be linearized in the PA output according to the system requirement without sacrificing performance, which makes the DPD system design much more flexible and feasible. In order to validate this idea, a high-power LDMOS Doherty PA excited by various wideband signals, including 100-MHz long-term evolution advanced signals, was tested. Experimental results showed that excellent linearization performance can be obtained by employing the proposed approach. Furthermore, this technique can be applied to other linear-in-parameter models. In future ultra-wideband systems, this new technique can significantly improve system performance and reduce DPD implementation cost.

Fuzzy Adaptive Internal Model Control Schemes for PMSM Speed-Regulation System

Abstract: In this paper, the speed regulation problem for permanent magnet synchronous motor (PMSM) system under vector control framework is studied. First, a speed regulation scheme based on standard internal model control (IMC) method is designed. For the speed loop, a standard internal model controller is first designed based on a first-order model of PMSM by analyzing the relationship between reference quadrature axis current and speed. For the two current loops, PI algorithms are employed respectively. Second, considering the disadvantages that the standard IMC method is sensitive to control input saturation and may lead to poor speed tracking and load disturbance rejection performances, a modified IMC scheme is developed based on a two-port IMC method, where a feedback control term is added to form a composite control structure. Third, considering the case of large variations of load inertia, two adaptive IMC schemes with two different adaptive laws are proposed. A method based on disturbance observer is adopted to identify the inertia of PMSM and its load. Then a linear adaptive law is developed by analyzing the relationship between the internal model and identified inertia. Considering the control input saturation in practical applications, a fuzzy adaptive law based IMC scheme is developed based on apriori experimental tests and experiences, where a fuzzy inferencer based supervisor is designed to automatically tune the parameter of speed controller according to the identified inertia. The effectiveness of the proposed methods have been verified by Matlab simulation and TMS320F2808 DSP experimental results.

Energy-Efficient Resource Allocation in OFDMA Networks

Abstract: The widespread application of multimedia wireless services and requirements of ubiquitous access have triggered rapidly booming energy consumption at both the base station side and the user equipment (UE) side. Hence, energy-efficient design in wireless networks is very important and is becoming an inevitable trend. In this paper, we study the energy-efficient resource allocation in both downlink and uplink cellular networks with orthogonal frequency division multiple access (OFDMA). For the downlink transmission, the generalized energy efficiency (EE) is maximized while for the uplink case the minimum individual EE is maximized, both under certain prescribed per-UE quality-of-service (QoS) requirements. For both transmission scenarios, we first provide the optimal solution and then develop a suboptimal but low-complexity approach by exploring the inherent structure and property of the energy-efficient design. For the downlink case, by modifying the original problem, we also find a computationally efficient and numerically tractable upper bound on the EE, which indicates the performance limit and is demonstrated to be quite tight if the number of subcarriers is larger than that of UEs and motivates us to find a near-optimal approach relying on the quasiconcave relation between the modified EE and transmit power. Simulation results show that the energy-efficient design greatly improves EE compared with the conventional spectral-efficient design and the low-complexity suboptimal approaches can achieve a promising tradeoff between performance and complexity.

A Survey on Delay-Aware Resource Control for Wireless Systems—Large Deviation Theory, Stochastic Lyapunov Drift, and Distributed Stochastic Learning

Abstract: In this paper, a comprehensive survey is given on several major systematic approaches in dealing with delay-aware control problems, namely the equivalentrate constraint approach, the Lyapunov stability drift approach, and the approximate Markov decision process approach using stochastic learning. These approaches essentially embrace most of the existing literature regarding delay-aware resource control in wireless systems. They have their relative pros and cons in terms of performance, complexity, and implementation issues. For each of the approaches, the problem setup, the general solution, and the design methodology are discussed. Applications of these approaches to delay-aware resource allocation are illustrated with examples in single-hop wireless networks. Furthermore, recent results regarding delay-aware multihop routing designs in general multihop networks are elaborated. Finally, the delay performances of various approaches are compared through simulations using an example of the uplink OFDMA systems.

Method and Wi-Fi device for setting communications mode

Abstract: An embodiment of the present invention discloses a Wi-Fi device, including a radio frequency circuit, a signal processor, an application processor, and a Wi-Fi chip. The application processor is configured to preset the work mode of the Wi-Fi chip to a single input single output SISO mode, and is further configured to acquire a value of a parameter of an uplink wireless network, and when the value of the parameter of the uplink wireless network is determined to be greater than or equal to a preset value, set the work mode of the Wi-Fi chip to a multiple-input multiple-output MIMO mode. An embodiment of the present invention further discloses a method for setting a communications mode.

Method and Apparatus for Internet Protocol Based Content Router

Abstract: An internet protocol (IP) content router, comprising a forwarding information base (FIB) engine comprising a data store comprising forwarding instructions, an IP packet classifier comprising a processor configured to classify a first incoming IP packet as an information centric networking (ICN) packet and a second incoming IP packet as a non-ICN packet, and an IP packet processor comprising a processor, wherein the IP packet processor is coupled to the FIB engine and to the IP packet classifier, wherein the IP packet processor is configured to intercept the ICN packet for further ICN processing in the IP content router, consult the FIB engine for forwarding instructions for the non-ICN packet, and forward the non-ICN packet according to the forwarding instructions.

Method, device and system for radio frequency device pairing

Abstract: A method for radio frequency device pairing includes: after a pairing instruction is received, sending a discovery request message to a second radio frequency device; receiving a discovery response message returned by the second radio frequency device; sending a first pairing request message to the second radio frequency device; receiving a first pairing response message returned by the second radio frequency device; after a button instruction entered by the user according to interface information displayed by the second radio frequency device is received, sending, to the second radio frequency device, a second pairing request message which contains button information corresponding to the button instruction; receiving a second pairing response message which is returned by the second radio frequency device and contains a confirmation result indicating that the button information and the interface information are successfully matched; exchanging keys with the target second radio frequency device, thereby completing pairing.

Collaborative forwarding and caching in content centric networks

Abstract: Content caching plays an important role in content-centric networks. The current design of content-centric networks adopts a limited, en-route hierarchical caching mechanism, and caching and forwarding are largely uncoordinated. In this paper, we propose a novel collaborative caching and forwarding design. In this design, collaboration is guided by content popularity ranking, based on which we introduce a collaborative forwarding table to allow coordination between caching and forwarding. We also propose a self-adaptive dual-segment cache division algorithm to deal with dynamic inconsistent content popularity. We evaluate our design via extensive simulations and demonstrate that our design improves content access cost and cache miss rate by at least 30% in a diverse network settings.

TV White Space in Europe

Abstract: In this paper, we study the availability of TV white spaces in Europe. Specifically, we focus on the 470-790 MHz UHF band, which will predominantly remain in use for TV broadcasting after the analog-to-digital switch-over and the assignment of the 800 MHz band to licensed services have been completed. The expected number of unused, available TV channels in any location of the 11 countries we studied is 56 percent when we adopt the statistical channel model of the ITU-R. Similarly, a person residing in these countries can expect to enjoy 49 percent unused TV channels. If, in addition, restrictions apply to the use of adjacent TV channels, these numbers reduce to 25 and 18 percent, respectively. These figures are significantly smaller than those recently reported for the United States. We also study how these results change when we use the Longley-Rice irregular terrain model instead. We show that while the overall expected availability of white spaces is essentially the same, the local variability of the available spectrum shows significant changes. This underlines the importance of using appropriate system models before making far-reaching conclusions.

Cell measurement method, cell resource sharing method, and related device

Abstract: Disclosed are a cell measurement method, a cell resource sharing method, and a related device. The cell measurement method includes: a user equipment receives a measurement configuration message sent by a base station, wherein the measurement configuration message comprises at least one physical cell identity and CSI-RS configuration information corresponding to a measured cell, and wherein the physical cell identity is used to indicate the measured cell; measuring the CSI-RS corresponding to the measured cell according to the CSI-RS configuration information, and obtaining a measurement result of the measuring; sending the obtained measurement result of the measured cell and measurement object information of the measured cell to the base station via a measurement report. The technical solution provided by the present invention can effectively improve the accuracy of the measurement result, and enable the base station to distinguish different measurement results corresponding to different cells.

LDPC convolutional codes using layered decoding algorithm for high speed coherent optical transmission

Abstract: We successfully realized layered decoding for LDPC convolutional codes designed for application in high speed optical transmission systems. A relatively short code with 20% redundancy was FPGA-emulated with a Q-factor of 5.7dB at BER of 10−15.

Intrachannel Nonlinearity Compensation by Inverse Volterra Series Transfer Function

Abstract: The Volterra series transfer function (VSTF), in which the input-output relationship of a nonlinear system is represented by a series of nonlinear kernel functions, is an elegant tool to model nonlinear systems. The inverse of a nonlinear system can be constructed by analyzing VSTF. We propose a new electronic nonlinearity compensation scheme based on inverse VSTF. We show 1 dB improvement in Q-factor with a 256 Gb/s polarization-division-multiplexed 16-level quadratic amplitude modulation format, and 50% reduction in complexity by lowering the processing rate.

Sparsity Order Estimation and its Application in Compressive Spectrum Sensing for Cognitive Radios

Abstract: Compressive sampling techniques can effectively reduce the acquisition costs of high-dimensional signals by utilizing the fact that typical signals of interest are often sparse in a certain domain. For compressive samplers, the number of samples Mr needed to reconstruct a sparse signal is determined by the actual sparsity order Snz of the signal, which can be much smaller than the signal dimension N. However, Snz is often unknown or dynamically varying in practice, and the practical sampling rate has to be chosen conservatively according to an upper bound Smax of the actual sparsity order in lieu of Snz, which can be unnecessarily high. To circumvent such wastage of the sampling resources, this paper introduces the concept of sparsity order estimation, which aims to accurately acquire Snz prior to sparse signal recovery, by using a very small number of samples Me less than Mr. A statistical learning methodology is used to quantify the gap between Mr and Me in a closed form via data fitting, which offers useful design guideline for compressive samplers. It is shown that Me ≥ 1.2Snz log(N/Snz + 2) + 3 for a broad range of sampling matrices. Capitalizing on this gap, this paper also develops a two-step compressive spectrum sensing algorithm for wideband cognitive radios as an illustrative application. The first step quickly estimates the actual sparsity order of the wide spectrum of interest using a small number of samples, and the second step adjusts the total number of collected samples according to the estimated signal sparsity order. By doing so, the overall sampling cost can be minimized adaptively, without degrading the sensing performance.

CL-PRE: a certificateless proxy re-encryption scheme for secure data sharing with public cloud

Abstract: We propose CL-PRE, a certificateless proxy re-encryption scheme for secure data sharing with public cloud, which leverages maximal cloud resources to reduce the computing and communication cost for data owner. Towards running proxy in public cloud environment, we further propose multi-proxy CL-PRE and randomized CL-PRE, which enhance the security and robustness of CL-PRE. We implement all CL-PRE schemes and evaluate their security and performance.

The Road to Immersive Communication

Abstract: Communication has seen enormous advances over the past 100 years including radio, television, mobile phones, video conferencing, and Internet-based voice and video calling. Still, remote communication remains less natural and more fatiguing than face-to-face. The vision of immersive communication is to enable natural experiences and interactions with remote people and environments in ways that suspend disbelief in being there. This paper briefly describes the current state-of-the-art of immersive communication, provides a vision of the future and the associated benefits, and considers the technical challenges in achieving that vision. The attributes of immersive communication are described, together with the frontiers of video and audio for achieving them. We emphasize that the success of these systems must be judged by their impact on the people who use them. Recent high-quality video conferencing systems are beginning to deliver a natural experience-when all participants are in custom-designed studios. Ongoing research aims to extend the experience to a broader range of environments. Augmented reality has the potential to make remote communication even better than being physically present. Future natural and effective immersive experiences will be created by drawing upon intertwined research areas including multimedia signal processing, computer vision, graphics, networking, sensors, displays and sound reproduction systems, haptics, and perceptual modeling and psychophysics.

OAuth Web Authorization Protocol

Abstract: Allowing one Web service to act on our behalf with another has become increasingly important as social Internet services such as blogs, photo sharing, and social networks have become widely popular. OAuth, a new protocol for establishing identity management standards across services, provides an alternative to sharing our usernames and passwords, and exposing ourselves to attacks on our online data and identities.

HEVC Lossless Coding and Improvements

Abstract: The lossless coding mode of the High Efficiency Video Coding (HEVC) main profile that bypasses transform, quantization, and in-loop filters is described. Compared to the HEVC nonlossless coding mode with the smallest quantization parameter value (i.e., 0 for 8-b video and -12 for 10-b video), the HEVC lossless coding mode provides perfect fidelity and an average bit-rate reduction of 3.2%-13.2%. It also significantly outperforms the existing lossless compression solutions, such as JPEG2000 and JPEG-LS for images as well as 7-Zip and WinRAR for data archiving. To further improve the coding efficiency of the HEVC lossless mode, a sample-based angular intra prediction (SAP) method is presented. The SAP employs the same prediction mode signaling method and the sample interpolation method as the HEVC block-based angular prediction, but uses adjacent neighbors for better intra prediction accuracy and performs prediction sample by sample. The experimental results reveal that the SAP provides an additional bit-rate reduction of 1.8%-11.8% on top of the HEVC lossless coding mode.

Method, apparatus, and communication system for transmitting graphic information

Abstract: The present invention discloses a method, an apparatus, and a communication system for transmitting graphic information. In the technical solution of the present invention, the graphic information carries a hyperlink and an identifier of the hyperlink so that when the terminal receives the graphic information, the terminal may judge, according to the identifier of the hyperlink, whether the hyperlink has been processed, and the terminal requests the graphic from the network according to the hyperlink only when determining that the hyperlink has not been processed, therefore ensuring an effective decrease in bandwidth consumption of broadcast or multicast channels, effectively avoiding repeated processing and presentation of a same hyperlink by the terminal, and reducing the complexity of the processing of the terminal.

On Receiver Design for Uplink Low Density Signature OFDM (LDS-OFDM)

Abstract: Low density signature orthogonal frequency division multiplexing (LDS-OFDM) is an uplink multi-carrier multiple access scheme that uses low density signatures (LDS) for spreading the symbols in the frequency domain. In this paper, we introduce an effective receiver for the LDS-OFDM scheme. We propose a framework to analyze and design this iterative receiver using extrinsic information transfer (EXIT) charts. Furthermore, a turbo multi-user detector/decoder (MUDD) is proposed for the LDS-OFDM receiver. We show how the turbo MUDD is tuned using EXIT charts analysis. By tuning the turbo-style processing, the turbo MUDD can approach the performance of optimum MUDD with a smaller number of inner iterations. Using the suggested design guidelines in this paper, we show that the proposed structure brings about 2.3 dB performance improvement at a bit error rate (BER) equal to 10-5 over conventional LDS-OFDM while keeping the complexity affordable. Simulations for different scenarios also show that the LDS-OFDM outperforms similar well-known multiple access techniques such as multi-carrier code division multiple access (MC-CDMA) and group-orthogonal MC-CDMA.

Method and apparatus for handling full-duplex interference

Abstract: The present invention provides a method and an apparatus for handling full-duplex interference. One method includes: obtaining an interference degree that is caused when a site device performs full-duplex transmission with at least two UEs; and determining, according to the interference degree, a UE allowed to transmit uplink and downlink signals on the same time and frequency resource among the at least two UEs. In embodiments of the present invention, a UE allowed to transmit uplink and downlink signals on the same time and frequency resource may be classified according to an interference degree that is caused when a site device performs full-duplex transmission with at least two UEs, thereby preventing the interference problem in the scenario of point-to-multipoint full-duplex communication as much as possible.