Ericsson (Netherlands)

A few years ago it was recognized that the vision of a truly low-cost, low-power radio-based cable replacement was feasible. Such a ubiquitous link would provide the basis for portable devices to communicate together in an ad hoc fashion by creating personal area networks which have similar advantages to their office environment counterpart, the local area network. Bluetooth/sup TM/ is an effort by a consortium of companies to design a royalty-free technology specification enabling this vision. This article describes the radio system behind the Bluetooth concept. Designing an ad hoc radio system for worldwide usage poses several challenges. The article describes the critical system characteristics and motivates the design choices that have been made.

We have measured the spin-dependent structure function ${g}_{1}^{p}$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1{\mathrm{GeV}}^{2}<{Q}^{2}<60{\mathrm{GeV}}^{2}.$ A next-to-leading order QCD analysis is used to evolve the measured ${g}_{1}^{p}{(x,Q}^{2})$ to a fixed ${Q}_{0}^{2}.$ The first moment of ${g}_{1}^{p}$ at ${Q}_{0}^{2}=10{\mathrm{GeV}}^{2}$ is ${\ensuremath{\Gamma}}_{1}^{p}=0.136\ifmmode\pm\else\textpm\fi{}0.013$ (stat) $\ifmmode\pm\else\textpm\fi{}0.009$ (syst) $\ifmmode\pm\else\textpm\fi{}0.005$ (evol). This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge ${a}_{0}$ is found to be $0.28\ifmmode\pm\else\textpm\fi{}0.16.$ In the Adler-Bardeen factorization scheme, $\ensuremath{\Delta}g\ensuremath{\simeq}2$ is required to bring \ensuremath{\Delta}\ensuremath{\Sigma} in agreement with the quark-parton model. A combined analysis of all available proton, deuteron, and ${}^{3}\mathrm{He}$ data confirms the Bjorken sum rule.

A few years ago it was recognized that the vision of a truly low-cost, low-power radio-based cable replacement was feasible. Such a ubiquitous link would provide the basis for portable devices to communicate together in an ad hoc fashion by creating personal area networks which have similar advantages to their office environment counterpart - the local area network (LAN). Bluetooth is an effort by a consortium of companies to design a royalty free technology specification enabling this vision. This article describes the vision and goals of the Bluetooth program and introduces the radio-based technology.

In the past decades, progress in microelectronics and VLSI technology has fostered the widespread use of computing and communication applications in portable electronic devices. In this paper, we review the Bluetooth technology, a new universal radio interface enabling electronic devices to connect and communicate wirelessly via short-range connections. Motivations for the air interface design and radio requirement decisions are discussed. Frequency hopping, interference resistance, and the concepts of ad hoc connectivity and scatternets are explained in detail. Furthermore, Bluetooth characteristics enabling low-cost single-chip implementations and supporting low power consumption are discussed.

A new radio interface named Bluetooth has been developed to provide short range connectivity between various consumer devices. The Bluetooth system operates in the unlicensed 2.45 GHz ISM band and applies frequency hopping over 79 carriers. This paper presents the simulation results of the radio network performance of a large number of co-located Bluetooth units. For a capacity-demanding WWW data traffic model, the interference caused by (on average) 100 concurrent sessions in a single room of size 10 m/spl times/20 m results only in a 5% degradation of the aggregate throughput. In general, it is advisable to use long uncoded packet types for data transmission since they have the largest ideal throughput and therefore generate the least interference power. For real-time speech links, frame erasures represent the dominant reason for transmission quality degradation, more than residual payload bit errors. It is thus advisable to use the provided uncoded packet type in order to allow for the largest capacity; a system load of about 30 Erlang yields an average frame erasure rate of 1%.

Recently there has been an enormous increase in efforts to open up telecommunication networks for application development. In opening up the network, new business models emerge where applications can be developed and provided by enterprises outside the traditional network operator domain. This new business model, combined with the fact that applications can be built using standardized API with off-the-shelf IT technology and tools, will result in new innovative applications that will hit the market with drastically reduced development cycles. This article provides an overview of the Parlay/OSA initiatives concerning the specification of a set of open standardized API. Furthermore, the article outlines some architectural aspects that are implied and implicitly contained in the Parlay/OSA specifications. These are critical for understanding the implications when allowing access to the network via Parlay/OSA. The article then outlines different types of applications that can be built using Parlay/OSA. Finally, we conclude with an analysis of the future of Parlay/OSA.

With the increasing use of multimedia technologies, image compression requires higher performance as well as new functionality. To address this need in the specific area of still image encoding, a new standard is currently being designed: JPEG2000. We see what the exact goals are of this future standard, which applications it addresses and the current standardisation process. Then we show through the descriptions of two available demonstrations what kind of results are already reachable with the current status of the standard. The first demonstration describes a Java implementation of the future standard, details the advantages of such an implementation and compares the performance of JPEG2000 with that of JPEG. The second demonstration describes how JPEG2000 can be used in domains were the transmission bandwidth is very restricted, taking advantages of new functions such as the definition of regions of interest and progressive transmission.

This paper describes the results of an implementation of a Bluetooth radio in a 0.18-/spl mu/m CMOS process. A low-IF image-reject conversion architecture is used for the receiver. The transmitter uses direct IQ-upconversion. The VCO runs at 4.8-5.0 GHz, thus facilitating the generation of 0/spl deg/ and 90/spl deg/ signals for both the receiver and transmitter. By using an inductor-less LNA and the extensive use of mismatch simulations, the smallest silicon area for a Bluetooth radio implementation so far can be reached: 5.5 mm/sup 2/. The transceiver consumes 30 mA in receive mode and 35 mA in transmit mode from a 2.5 to 3.0-V power supply. As the radio operates on the same die as baseband and SW, the crosstalk-on-silicon is an important issue. This crosstalk problem was taken into consideration from the start of the project. Sensitivity was measured at -82 dBm.

A Bluetooth radio in 0.18 /spl mu/m CMOS technology works on 2.5-3.0 V, dissipating 75 mW in RX and 90 mW in TX. RX uses a 2 MHz IF with an active poly-phase bandpass filter. The fractional-N PLL uses a VCO running at 5 GHz. TX uses IQ modulation. Special attention is paid to Si-crosstalk because this radio is combined with baseband circuitry. Silicon area is 5.5 mm/sup 2/.

Single-Rate Data-Flow (SRDF) graphs, also known as Homogeneous Synchronous Data-Flow (HSDF) graphs or Marked Graphs, are often used to model the implementation and do temporal analysis of concurrent DSP and multimedia applications. An important problem in implementing applications expressed as SRDF graphs is the computation of the minimal amount of buffering needed to implement a static periodic schedule (SPS) that is optimal in terms of execution rate, or throughput. Ning and Gao [1] propose a linear-programming-based polynomial algorithm to compute this minimal storage amount, claiming optimality. We show via a counterexample that the proposed algorithm is not optimal. We prove that the problem is, in fact, NP-complete. We give an exact solution, and experimentally evaluate the degree of inaccuracy of the algorithm of Ning and Gao.

Viterbi algorithm is widely used as a decoding technique for convolutional codes as well as a bit detection method in storage devices. The design space for VLSI implementation of Viterbi decoders is huge, involving choices of throughput, latency, area, and power. Even for a fixed set of parameters like constraint length, encoder polynomials and trace-back depth, the task of designing a Viterbi decoder is quite complex and requires significant effort. Sometimes, due to incomplete design space exploration or incorrect analysis, a suboptimal design is chosen. This work analyzes the design complexity by applying most of the known VLSI implementation techniques for hard-decision Viterbi decoding to a different set of code parameters. The conclusions are based on real designs for which actual synthesis and layouts were obtained. In authors' view, due to the depth covered, it is the most comprehensive analysis of the topic published so far.

Energy efficient execution of applications is important for many reasons, e.g. time between battery charges, device temperature. Voltage and Frequency Scaling (VFS) enables applications to be run at lower frequencies on hardware resources thereby consuming less power. Real-time applications have deadlines that must be met otherwise their output is devalued. Dataflow modelling of real-time applications enables off-line verification of the application's temporal requirements. In this paper we describe a method to reduce the combined static and dynamic energy consumption using a Dynamic VFS (DVFS) technique for dataflow modelled real-time applications that may be mapped onto multiple hardware resources. We achieve this by using an application's static slack in order to perform DVFS while still satisfying the application's temporal requirements. We show that by formulating a dataflow modelled application and its mapping as a convex optimisation problem, with energy consumption as the objective function, the problem can be solved with a generic convex optimisation solver, producing an energy optimal constant frequency per application task. Our method allows task frequencies to be constrained such that, e.g. one frequency per application or per processor may be achieved.

Abstract Recently, a new universal radio interface was developed enabling electronic devices to connect and communicate via short‐range radio links. The Bluetooth radio technology is regarded as a complement and an extension to existing wireless technologies, addressing the short‐range and inter‐device connectivity. The technology allows the design of low‐power, small‐sized, and low‐cost radios that can be embedded in a wide range of consumer products.

AIM: This study investigates the effectiveness of a recovery-oriented training program on knowledge and attitudes of mental health care professionals towards recovery of people with serious mental illness. METHODS: Using data from a longitudinal study of recovery, changes in knowledge and attitudes of 210 mental health care professionals towards recovery were explored using the Recovery Attitude Questionnaire and the Recovery Knowledge Inventory. The study uses a two-group multiple intervention interrupted time-series design which is a variant of the stepped-wedge trial design. A total of six measurements occasions took place. RESULTS: This study shows that professionals' attitudes towards recovery from mental illness can improve with training. After two intensive recovery-oriented training sessions, mental health care professionals have a more positive attitude towards recovery in clinical practice. CONCLUSION: A recovery-oriented training program can change attitudes of mental health care professionals towards recovery of serious mental illness.

Dynamic spectrum sharing between uncoordinated systems of the same kind or even between systems using different technologies is attracting an increasing interest. Closely related is also "bandwidth on demand" for different services within a system. Traditional frequency planning is more difficult and less spectrum efficient the smaller the cells become. For indoor cells the practical planning limit is definitely passed. Continuous or instant dynamic sharing makes it possible to avoid to plan the channel assignments within a system and between systems. This paper presents analysis and simulations on dynamic spectrum sharing.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Like so many other major companies in the world today, Ericsson runs most of its product development operations as projects. The increasing complexity of telecommunication solutions often requires that many technologies are brought together in one turnkey project, such as telephone switching, mobile radio networks, DECT radio Access and others. Competence centres within Ericsson, spread out over many countries need to work together in‘cross functional’ projects. While the advantage of the project concept is obvious, carrying out projects in which various Ericsson companies participate, in different countries, can prove to be a very complex undertaking. Many such projects are running simultaneously and often compete for resources and priority with ever increasing time constraints. In order to succeed we need a common methodology for managing projects. This methodology must provide Ericsson with a shared view on how we allocate scarce (human) resources, the roles that need to be played by all those involved in the project and the supporting line functions, the criteria to be used for decisions to be taken inside the project and in relation to other projects, and many more issues that require a common view. A shared view on project management is also a prerequisite for handling conflicts within an organization in which the project, as a working form, is predominant. Various Ericsson companies and units have achieved different degrees of maturity in their management of projects. This combined experience has produced a methodology called ‘PROPS’ that Ericsson uses today. The widespread use of PROPS has given Ericsson a common terminology and common perspective of projects. This contributes to shorter lead‐time, time to market and time to customer. In this article is explained some of the PROPS features and how PROPS is applied.

Multi-path fading gives rise to frequency-dependent channel conditions. For narrowband TDD systems, channel conditions in uplink and downlink (or forward and reverse) can be assumed reciprocal. For broadband TDD systems applying frequency domain scheduling, reciprocal channel conditions are no longer valid. Using the coherence bandwidth for assessing the correlation between uplink and downlink can lead to invalid conclusions. By using cumulative distribution functions derived from a large number of channel realizations, it is shown that the radio attenuation at relatively small frequency offsets can differ by several dBs for a large percentage of the cases. This is particularly a problem in cognitive (UWB) radios that apply detect-and-avoid techniques and rely on uplink detection to protect the downlink reception. Until now, non-reciprocity between uplink and downlink channels was considered a challenge in case of detecting FDD systems. However, in this paper it is shown that even for detecting broadband TDD systems, reciprocity between uplink and downlink channels can no longer be assumed. Other challenges arise when adaptive antennas are used without feedback and downlink parameters are based on uplink measurements.

This draft presents the work on the framework for the Resource Management in Diffserv (RMD) designed for edge-to-edge resource reservation in a Differentiated Services (Diffserv) domain. The RMD extends the Diffserv architecture with new resource reservation concepts and features. Moreover, this framework enhances the Load Control protocol described in [WeTu00]. The RMD framework defines two architectural concepts: - the Per Hop Reservation (PHR) - the Per Domain Reservation (PDR) The PHR protocol is used within a Diffserv domain on a per-hop basis to augment the Diffserv Per Hop Behavior (PHB) with resource reservation. It is implemented in all nodes in a Diffserv domain. On the other hand, the PDR protocol manages the resource reservation per Diffserv domain, relying on the PHR resource reservation status in all nodes. The PDR is only implemented at the boundary of the domain (at the edge nodes). The RMD framework presented in this draft describes the new reservation concepts and features. Furthermore it describes the: - relationship between the PHR and PHB - interaction between the PDR and PHR - interoperability between the PDR and external resource reservation schemes This framework is an open framework in the sense that it provides the basis for interoperability with other resource reservation schemes and can be applied in different types of networks as long as they are Diffserv domains. It aims at extreme simplicity and low cost of implementation along with good scaling properties.

In this study a scheduling algorithm for CDMA systems is presented which is a trade-off between two extreme ways of scheduling: C/I based and Round-Robin scheduling. The simulation results indeed display that the advantages of both these extremes have been combined in the new algorithm: a good fairness, comparable to that of the Round-Robin scheduling, together with almost the same power gain as reached in the C/I based scheduling. I.

Contemporary embedded systems for wireless communications support various radios. A software-defined radio (SDR) is a radio implemented as concurrent software processes that typically run on a multiprocessor system-on-chip (MPSoC). SDRs are real-time streaming applications with throughput requirements. One efficient approach for timing analysis of concurrent real-time applications is the dataflow model of computation (MoC). Nonetheless, the dataflow modeling of SDRs is challenging due to their dynamically changing data processing workload. A dataflow MoC that is not expressive enough to capture this dynamism gives pessimistic throughput results. On the other hand, if it is too expressive and detailed, it may not be analyzable at all. In this paper, we address the challenge of dataflow modeling of SDRs such that their timing behavior can be accurately analyzed to guarantee real-time requirements without unnecessarily over-allocating MPSoC resources. The basis of our modeling approach is splitting the dynamic data processing behavior of a SDR into a group of static modes of operation. Each static mode of operation is then modeled by a Synchronous Dataflow (SDF), which we refer to as scenario. This paper has two main contributions: 1) a scenario-based dataflow model of Long Term Evolution (LTE), which is the latest standard in cellular communication, and 2) investigation of existing throughput analysis techniques of SDF scenarios for our LTE model. Our results show that scenario-based worst-case throughput computation is 2 to 3.4 times more accurate than a state-of-the-art SDF analysis technique. Our investigation also shows that existing timing analysis techniques of SDF scenarios have very low run-time that scales very well with increase in graph size. This makes SDF scenarios suitable in practice for modeling and analyzing SDRs as well as similar dynamic applications.