Showing papers by "Nokia published in 2009"

Device-to-device communication as an underlay to LTE-advanced networks

Abstract: In this article device-to-device (D2D) communication underlaying a 3GPP LTE-Advanced cellular network is studied as an enabler of local services with limited interference impact on the primary cellular network. The approach of the study is a tight integration of D2D communication into an LTE-Advanced network. In particular, we propose mechanisms for D2D communication session setup and management involving procedures in the LTE System Architecture Evolution. Moreover, we present numerical results based on system simulations in an interference limited local area scenario. Our results show that D2D communication can increase the total throughput observed in the cell area.

Stochastic geometry and random graphs for the analysis and design of wireless networks

Abstract: Wireless networks are fundamentally limited by the intensity of the received signals and by their interference. Since both of these quantities depend on the spatial location of the nodes, mathematical techniques have been developed in the last decade to provide communication-theoretic results accounting for the networks geometrical configuration. Often, the location of the nodes in the network can be modeled as random, following for example a Poisson point process. In this case, different techniques based on stochastic geometry and the theory of random geometric graphs -including point process theory, percolation theory, and probabilistic combinatorics-have led to results on the connectivity, the capacity, the outage probability, and other fundamental limits of wireless networks. This tutorial article surveys some of these techniques, discusses their application to model wireless networks, and presents some of the main results that have appeared in the literature. It also serves as an introduction to the field for the other papers in this special issue.

Understanding, scoping and defining user experience: a survey approach

Abstract: Despite the growing interest in user experience (UX), it has been hard to gain a common agreement on the nature and scope of UX. In this paper, we report a survey that gathered the views on UX of 275 researchers and practitioners from academia and industry. Most respondents agree that UX is dynamic, context-dependent, and subjective. With respect to the more controversial issues, the authors propose to delineate UX as something individual (instead of social) that emerges from interacting with a product, system, service or an object. The draft ISO definition on UX seems to be in line with the survey findings, although the issues of experiencing anticipated use and the object of UX will require further explication. The outcome of this survey lays ground for understanding, scoping, and defining the concept of user experience.

PEIR, the personal environmental impact report, as a platform for participatory sensing systems research

Abstract: PEIR, the Personal Environmental Impact Report, is a participatory sensing application that uses location data sampled from everyday mobile phones to calculate personalized estimates of environmental impact and exposure. It is an example of an important class of emerging mobile systems that combine the distributed processing capacity of the web with the personal reach of mobile technology. This paper documents and evaluates the running PEIR system, which includes mobile handset based GPS location data collection, and server-side processing stages such as HMM-based activity classification (to determine transportation mode); automatic location data segmentation into "trips''; lookup of traffic, weather, and other context data needed by the models; and environmental impact and exposure calculation using efficient implementations of established models. Additionally, we describe the user interface components of PEIR and present usage statistics from a two month snapshot of system use. The paper also outlines new algorithmic components developed based on experience with the system and undergoing testing for integration into PEIR, including: new map-matching and GSM-augmented activity classification techniques, and a selective hiding mechanism that generates believable proxy traces for times a user does not want their real location revealed.

A framework of energy efficient mobile sensing for automatic user state recognition

Abstract: Urban sensing, participatory sensing, and user activity recognition can provide rich contextual information for mobile applications such as social networking and location-based services. However, continuously capturing this contextual information on mobile devices consumes huge amount of energy. In this paper, we present a novel design framework for an Energy Efficient Mobile Sensing System (EEMSS). EEMSS uses hierarchical sensor management strategy to recognize user states as well as to detect state transitions. By powering only a minimum set of sensors and using appropriate sensor duty cycles EEMSS significantly improves device battery life. We present the design, implementation, and evaluation of EEMSS that automatically recognizes a set of users' daily activities in real time using sensors on an off-the-shelf high-end smart phone. Evaluation of EEMSS with 10 users over one week shows that our approach increases the device battery life by more than 75% while maintaining both high accuracy and low latency in identifying transitions between end-user activities.

Mobile communications matching system

Abstract: A wireless communications network comprises a server in a central location storing matching profiles for a plurality of users of the network. The matching profile for each user is stored in the server through the user's mobile unit or a secure page on the Internet. Each matching profile is corresponded with a respective mobile unit using the same identification information (ID) of the respective mobile unit utilized for carrying out phone calls. The server has a customizable variable matching algorithm and probes the matching profiles corresponding to the respective mobile units in a cell or group of cells for a match every time a new mobile unit subscribes into the cell or group of cells. When there is a match of matching profiles, the two persons are put in contact or advised of each other through a phone call or other communications method.

Interference-Aware Resource Allocation for Device-to-Device Radio Underlaying Cellular Networks

Abstract: Future cellular networks such as IMT-Advanced are expected to allow underlaying direct Device-to-Device (D2D) communication for spectrally efficient support of eg rich multimedia local services Enabling D2D links in a cellular network presents a challenge in radio resource management due to the potentially severe interference it may cause to the cellular network We propose a practical and efficient scheme for generating local awareness of the interference between the cellular and D2D terminals at the base station, which then exploits the multiuser diversity inherent in the cellular network to minimize the interference System simulations demonstrate that substantial gains in cellular and D2D performance can be obtained using the proposed scheme

Power Optimization of Device-to-Device Communication Underlaying Cellular Communication

Abstract: We address resource sharing of the cellular network and a device-to-device (D2D) underlay communication assuming that the cellular network has control over the transmit power and the radio resources of D2D links. We show that by proper power control, the interference between two services can be coordinated to benefit the overall performance. In addition, we consider a scenario with prioritized cellular communication and an upper limit on the maximum transmission rate of all links. We derive the optimum power allocation for the considered resource sharing modes. The results show that cellular service can be effectively guaranteed while having a comparable sum rate with a none power control case in most of the cell area.

Collaborative Cyclostationary Spectrum Sensing for Cognitive Radio Systems

Abstract: This paper proposes an energy efficient collaborative cyclostationary spectrum sensing approach for cognitive radio systems. An existing statistical hypothesis test for the presence of cyclostationarity is extended to multiple cyclic frequencies and its asymptotic distributions are established. Collaborative test statistics are proposed for the fusion of local test statistics of the secondary users, and a censoring technique in which only informative test statistics are transmitted to the fusion center (FC) during the collaborative detection is further proposed for improving energy efficiency in mobile applications. Moreover, a technique for numerical approximation of the asymptotic distribution of the censored FC test statistic is proposed. The proposed tests are nonparametric in the sense that no assumptions on data or noise distributions are required. In addition, the tests allow dichotomizing between the desired signal and interference. Simulation experiments are provided that show the benefits of the proposed cyclostationary approach compared to energy detection, the importance of collaboration among spatially displaced secondary users for overcoming shadowing and fading effects, as well as the reliable performance of the proposed algorithms even in very low signal-to-noise ratio (SNR) regimes and under strict communication rate constraints for collaboration overhead.

Toward physical activity diary: motion recognition using simple acceleration features with mobile phones

Abstract: In this paper, we perform physical motion recognition using mobile phones with built-in accelerometer sensors. Sensor data processing and smoothing techniques are discussed first to reduce the special noise present in phone-collected accelerometer data. We explore orientation-independent features extracted from vertical and horizonal components in acceleration as well as magnitudes of acceleration for six common physical activities, such as sitting, standing, walking, running, driving and bicycling. We find decision tree achieves the best performance among four commonly used static classifiers, while vertical and horizonal features have better recognition accuracy than magnitude features. Furthermore, a well-pruned decision tree with simple time domain features and less over-fitting on the training data can provide a usable model for inferencing a physical activity diary, refined by a similarity match from K-means clustering results and smoothed by an HMM-based Viterbi algorithm.

On the Performance of Device-to-Device Underlay Communication with Simple Power Control

Abstract: We address device-to-device (D2D) communication as a potential resource reuse technique underlaying the cellular network. We consider the shared channel of the two systems as an interference channel and formulate the statistics of the signal to interference plus noise ratio (SINR) of all users. The potential performance of D2D communication is evaluated by considering a scenario where only limited interference coordination between the cellular and the D2D communication is possible. We apply a simple power control method to the D2D communication which constrains the SINR degradation of the cellular link to a certain level. Results show that the SINR statistics of the D2D users is comparable to that of the cellular user in most of the cell area. Scheduling gain is possible by properly assigning either of the downlink (DL) or the uplink (UL) resources to the D2D communication.

A parsimonious model of mobile partitioned networks with clustering

Abstract: Mobile wireless networks frequently possess, at the same time, both dense and sparse regions of connectivity; for example, due to a heterogeneous node distribution or radio propagation environment. This paper is about modeling both the mobility and the formation of clusters in such networks, where nodes are concentrated in clusters of dense connectivity, interspersed with sparse connectivity. Uniformly dense and sparse networks have been extensively studied in the past, but not much attention has been devoted to clustered networks.

Apparatus and method for dynamic communication resource allocation for device-to-device communications in a wireless communication system

Abstract: An apparatus, system and method to dynamically manage an allocation of communication resources for direct device-to-device communications between a plurality of wireless communication devices in a wireless communication system. In one embodiment, the apparatus (410) includes a communication resource allocator (420) configured to: (1) select a master communication device of a plurality of wireless communication devices that form a device-to-device group, (2) provide an allocation of communication resources for device-to-device group that facilitate direct device-to-device communications therebetween. The apparatus (410) also includes a message generator (430) configured to assemble messages that include the allocation of the communication resources.

CHoG: Compressed histogram of gradients A low bit-rate feature descriptor

Abstract: Establishing visual correspondences is an essential component of many computer vision problems, and is often done with robust, local feature-descriptors. Transmission and storage of these descriptors are of critical importance in the context of mobile distributed camera networks and large indexing problems. We propose a framework for computing low bit-rate feature descriptors with a 20× reduction in bit rate. The framework is low complexity and has significant speed-up in the matching stage. We represent gradient histograms as tree structures which can be efficiently compressed. We show how to efficiently compute distances between descriptors in their compressed representation eliminating the need for decoding. We perform a comprehensive performance comparison with SIFT, SURF, and other low bit-rate descriptors and show that our proposed CHoG descriptor outperforms existing schemes.

Weighted Sum-Rate Maximization Using Weighted MMSE for MIMO-BC Beamforming Design

Abstract: This paper studies linear transmit filter design for Weighted Sum-Rate (WSR) maximization in the Multiple Input Multiple Output Broadcast Channel (MIMO-BC). The problem of finding the optimal transmit filter is non-convex and intractable to solve using low complexity methods. Motivated by recent results highlighting the relationship between mutual information and Minimum Mean Square Error (MMSE), this paper establishes a relationship between weighted sum-rate and weighted MMSE in the MIMO-BC. The relationship is used to propose a low complexity algorithm for finding a local weighted sum-rate optimum based on alternating optimization. Numerical results studying sum-rate show that the proposed algorithm achieves high performance with few iterations.

Hand gesture recognition and virtual game control based on 3D accelerometer and EMG sensors

Abstract: This paper describes a novel hand gesture recognition system that utilizes both multi-channel surface electromyogram (EMG) sensors and 3D accelerometer (ACC) to realize user-friendly interaction between human and computers. Signal segments of meaningful gestures are determined from the continuous EMG signal inputs. Multi-stream Hidden Markov Models consisting of EMG and ACC streams are utilized as decision fusion method to recognize hand gestures. This paper also presents a virtual Rubik's Cube game that is controlled by the hand gestures and is used for evaluating the performance of our hand gesture recognition system. For a set of 18 kinds of gestures, each trained with 10 repetitions, the average recognition accuracy was about 91.7% in real application. The proposed method facilitates intelligent and natural control based on gesture interaction.

Interference avoidance mechanisms in the hybrid cellular and device-to-device systems

Abstract: A hybrid system of cellular mode and device-to-device (D2D) mode is considered in this paper, where the cellular uplink resource is reused by the D2D transmission. In order to maximize the overall system performance, the mutual interference between cellular and D2D sub-systems has to be addressed. Here, two mechanisms are proposed to solve the problem: One is mitigating the interference from cellular transmission to D2D communication by an interference tracing approach. The other one is aiming to reduce the interference from D2D transmission to cellular communication by a tolerable interference broadcasting approach. Both mechanisms can work independently or jointly to synergy the transmission in the hybrid system for the efficient resource utilization. In the end, simulation is conducted to study the performance of the proposed schemes, which shows satisfying results.

The emerging MVC standard for 3D video services

Abstract: Multiview video has gained a wide interest recently. The huge amount of data needed to be processed by multiview applications is a heavy burden for both transmission and decoding. The joint video team has recently devoted part of its effort to extend the widely deployed H.264/AVC standard to handle multiview video coding (MVC). The MVC extension of H.264/AVC includes a number of new techniques for improved coding efficiency, reduced decoding complexity, and new functionalities for multiview operations. MVC takes advantage of some of the interfaces and transport mechanisms introduced for the scalable video coding (SVC) extension of H.264/AVC, but the system level integration of MVC is conceptually more challenging as the decoder output may contain more than one view and can consist of any combination of the views with any temporal level. The generation of all the output views also requires careful consideration and control of the available decoder resources. In this paper, multiview applications and solutions to support generic multiview as well as 3D services are introduced. The proposed solutions, which have been adopted to the draft MVC specification, cover a wide range of requirements for 3D video related to interface, transport of the MVC bitstreams, and MVC decoder resource management. The features that have been introduced in MVC to support these solutions include marking of reference pictures, supporting for efficient view switching, structuring of the bitstream, signalling of view scalability supplemental enhancement information (SEI) and parallel decoding SEI.

Artifact-free High Dynamic Range imaging

Abstract: The contrast in real world scenes is often beyond what consumer cameras can capture. For these situations, High Dynamic Range (HDR) images can be generated by taking multiple exposures of the same scene. When fusing information from different images, however, the slightest change in the scene can generate artifacts which dramatically limit the potential of this solution. We present a technique capable of dealing with a large amount of movement in the scene: we find, in all the available exposures, patches consistent with a reference image previously selected from the stack. We generate the HDR image by averaging the radiance estimates of all such regions and we compensate for camera calibration errors by removing potential seams. We show that our method works even in cases when many moving objects cover large regions of the scene.

New data indicator for persistently allocated packets in a communication system

Abstract: An apparatus 310 employable in a communication system configured to determine a value for a new data indicator for semi-persistently allocated or scheduled resources. In one embodiment, the apparatus 310 includes a processor 320 configured to receive a cell radio network temporary identifier indicating a semi-persistent scheduling. The processor 320 is also configured to treat a reception of data with a new data indicator flag in accordance with the semi- persistent scheduling as one of a persistent initial transmission if a value of the new data indicator flag is equal to a first predefined value, and a retransmission of semi-persistent scheduling data if the value of the new data indicator flag is equal to a second predefined value.

Device-to-Device Communications; Functional Prospects for LTE-Advanced Networks

Abstract: In this paper the possibility of device-to-device (D2D) communications as an underlay of an LTE-A network is introduced. The D2D communication enables new service opportunities and reduces the eNB load for short range data intensive peer-to-peer communication. The cellular network may establish a new type of radio bearer dedicated for D2D communications and stay in control of the session setup and the radio resources without routing the user plane traffic. The paper addresses critical issues and functional blocks to enable D2D communication as an add-on functionality to the LTE SAE architecture. Unlike 3G spread spectrum cellular and OFDM WLAN techniques, LTE-A resource management is fast and operates in high time-frequency resolution. This could allow the use of non-allocated time-frequency resources, or even partial reuse of the allocated resources for D2D with eNB controlled power constraints. The feasibility and the range of D2D communication, and its impact to the power margins of cellular communications are studied by simulations in two example scenarios. The results demonstrate that by tolerating a modest increase in interference, D2D communication with practical range becomes feasible. By tolerating higher interference power the D2D range will increase.

SURFTrac: Efficient tracking and continuous object recognition using local feature descriptors

Abstract: We present an efficient algorithm for continuous image recognition and feature descriptor tracking in video which operates by reducing the search space of possible interest points inside of the scale space image pyramid. Instead of performing tracking in 2D images, we search and match candidate features in local neighborhoods inside the 3D image pyramid without computing their feature descriptors. The candidates are further validated by fitting to a motion model. The resulting tracked interest points are more repeatable and resilient to noise, and descriptor computation becomes much more efficient because only those areas of the image pyramid that contain features are searched. We demonstrate our method on real-time object recognition and label augmentation running on a mobile device.

Increasing downlink cellular throughput with limited network MIMO coordination

Abstract: Single-user, multiuser, and network MIMO performance is evaluated for downlink cellular networks with 12 antennas per site, sectorization, universal frequency reuse, scheduled packet-data, and a dense population of stationary users. Compared to a single-user MIMO baseline system with 3 sectors per site, network MIMO coordination is found to increase throughput by a factor of 1.8 with intra-site coordination among antennas belonging to the same cell site. Intra-site coordination performs almost as well as a highly sectorized system with 12 sectors per site. Increasing the coordination cluster size from 1 to 7 sites increases the throughput gain factor to 2.5.

Method, Apparatus and Computer Program Product for Allocating Resources in Wireless Communication Network

Abstract: The present application discloses a method, an apparatus and a computer program product for allocating resources for a Device-to-Device (D2D) direct communication user equipment in a wireless communication network, wherein the method comprise: transmitting a communication channel status report regarding Device-to-Device direct communication to a base station; receiving resource allocation instructions generated by the base station based on the communication channel status report; and performing Device-to-Device direct communication between user equipments on the allocated resources; the disclosed apparatus comprises transmitting means for transmitting a communication channel status report regarding Device-to-Device direct communication to a base station; receiving means for receiving resource allocation instructions generated by the base station based on the communication channel status report; and performing means for performing Device-to-Device direct communication between user equipments on the allocated resources. By using the method, apparatus and computer program product disclosed in the present application, resource sharing/allocation collision between the D2D user equipment and cellular user equipment can be effectively reduced and use rate of resources can be improved.

Gaussian KD-trees for fast high-dimensional filtering

Abstract: We propose a method for accelerating a broad class of non-linear filters that includes the bilateral, non-local means, and other related filters. These filters can all be expressed in a similar way: First, assign each value to be filtered a position in some vector space. Then, replace every value with a weighted linear combination of all values, with weights determined by a Gaussian function of distance between the positions. If the values are pixel colors and the positions are (x, y) coordinates, this describes a Gaussian blur. If the positions are instead (x, y, r, g, b) coordinates in a five-dimensional space-color volume, this describes a bilateral filter. If we instead set the positions to local patches of color around the associated pixel, this describes non-local means. We describe a Monte-Carlo kd-tree sampling algorithm that efficiently computes any filter that can be expressed in this way, along with a GPU implementation of this technique. We use this algorithm to implement an accelerated bilateral filter that respects full 3D color distance; accelerated non-local means on single images, volumes, and unaligned bursts of images for denoising; and a fast adaptation of non-local means to geometry. If we have n values to filter, and each is assigned a position in a d-dimensional space, then our space complexity is O(dn) and our time complexity is O(dn log n), whereas existing methods are typically either exponential in d or quadratic in n.

Coalitional Games for Distributed Collaborative Spectrum Sensing in Cognitive Radio Networks

Abstract: Collaborative spectrum sensing among secondary users (SUs) in cognitive networks is shown to yield a significant performance improvement. However, there exists an inherent trade off between the gains in terms of probability of detection of the primary user (PU) and the costs in terms of false alarm probability. In this paper, we study the impact of this trade off on the topology and the dynamics of a network of SUs seeking to reduce the interference on the PU through collaborative sensing. Moreover, while existing literature mainly focused on centralized solutions for collaborative sensing, we propose distributed collaboration strategies through game theory. We model the problem as a non-transferable coalitional game, and propose a distributed algorithm for coalition formation through simple merge and split rules. Through the proposed algorithm, SUs can autonomously collaborate and self-organize into disjoint independent coalitions, while maximizing their detection probability taking into account the cooperation costs (in terms of false alarm). We study the stability of the resulting network structure, and show that a maximum number of SUs per formed coalition exists for the proposed utility model. Simulation results show that the proposed algorithm allows a reduction of up to 86.6% of the average missing probability per SU (probability of missing the detection of the PU) relative to the non-cooperative case, while maintaining a certain false alarm level. In addition, through simulations, we compare the performance of the proposed distributed solution with respect to an optimal centralized solution that minimizes the average missing probability per SU. Finally, the results also show how the proposed algorithm autonomously adapts the network topology to environmental changes such as mobility.

Apparatus and method ofscheduling resources for device-to-device communications

Abstract: An approach is provided for scheduling resources for device-to-device communications. A resource of a network is granted to a group designated for device-to-device communications. The group then determines how the resource allocation is utilized to support the communication session and allocates the resource among the user equipment within the group independently of the base station. Further, a user equipment pair in the group determines transmit/receive (Tx/Rx) timeslot configuration to allow TDD mode operations, and further configure the modulation and coding for the device-to-device connection, and error control scheme for the pair via control signaling independently from the group.

Like bees around the hive: a comparative study of a mobile augmented reality map

Abstract: We present findings from field trials of MapLens, a mobile augmented reality (AR) map using a magic lens over a paper map. Twenty-six participants used MapLens to play a location-based game in a city centre. Comparisons to a group of 11 users with a standard 2D mobile map uncover phenomena that arise uniquely when interacting with AR features in the wild. The main finding is that AR features facilitate place-making by creating a constant need for referencing to the physical, and in that it allows for ease of bodily configurations for the group, encourages establishment of common ground, and thereby invites discussion, negotiation and public problem-solving. The main potential of AR maps lies in their use as a collaborative tool.

Method and device for video coding and decoding

Abstract: Embodiments of the present invention relate to video coding for multi-view video content. It provides a coding system enabling scalability for the multi-view video content. In one embodiment, a method is provided for encoding at least two views representative of a video scene, each of the at least two views being encoded in at least two scalable layers, wherein one of the at least two scalable layers representative of one view of the at least two views is encoded with respect to a scalable layer representative of the other view of the at least two views.

Dynamic allocation of subframe scheduling for time division duplex operation in a packet-based wireless communication system

Abstract: Systems and methods for enabling the dynamic allocation of certain sub frames as downlink or uplink resources in a time division duplexed over the air communications system. A base station or eNB may allocate certain subframes within a repeating radio frame of a TDD configuration as either DL or UL subframes for communicating to user equipment or UE devices to increase efficient use of system resources based on the data to be transmitted. Methods for determining the capabilities of a selected UE and based on the determining step, dynamically allocating certain subframes are disclosed. The methods and systems are compatible with user equipment that does not support the dynamic allocation of subframes.