Showing papers by "Timo Hämäläinen published in 2003"
28 Apr 2003
TL;DR: The design and implementation of the Bluetooth local positioning application based on received power levels, which is converted to distance estimates according to a simple propagation model, and the extended Kalman filter computes a 3D position estimate on the basis of distance estimates.
Abstract: This paper presents the design and implementation of the Bluetooth local positioning application. Positioning is based on received power levels, which are converted to distance estimates according to a simple propagation model. The extended Kalman filter computes a 3D position estimate on the basis of distance estimates. With the used Bluetooth hardware, the mean absolute error of positioning was measured to be 3.76 m. The accuracy can be improved if Bluetooth devices are able to measure received power levels more precisely.
180 citations
TL;DR: An analysis of computational complexity is presented for an H.26L video decoder, based on extensive experiments on a general-purpose processor and platform-independent techniques to optimize an H-26L decoder implementation are given.
Abstract: An analysis of computational complexity is presented for an H.26L video decoder, based on extensive experiments on a general-purpose processor. In addition, platform-independent techniques to optimize an H.26L decoder implementation are given. Comparisons are carried out between our highly optimized version of H.26L, the public reference implementation of H.26L, and a highly optimized H.263+ implementation. Both QCIF and CIF-sized image sequences are used. The results show that with equal visual quality, the bit-rate savings range from 28% to 58%, while the frame decoding speed of H.26L is about 11% better than that of a highly optimized H.263+.
108 citations
07 Sep 2003
TL;DR: The prototype implements received signal power level based positioning on IEEE 802.11b wireless LAN (WLAN) platform and includes a host PC, which runs a positioning application, which computes and displays position estimates on the basis of measurements performed by the WLAN adapter.
Abstract: This paper presents the design and implementation of a local positioning prototype The prototype implements received signal power level based positioning on IEEE 80211b wireless LAN (WLAN) platform In addition to a WLAN adapter, the prototype includes a host PC, which runs a positioning application The application computes and displays position estimates on the basis of measurements performed by the WLAN adapter A signal propagation model and an extended Kalman filter are used for enhancing the position estimates With the used WLAN hardware, the mean absolute error of positioning was measured to be 26 m
77 citations
Patent•
29 Oct 2003TL;DR: A configurable protocol engine (CPE) as mentioned in this paper is capable of constructing a desired protocol structure (112) according to the received configuration information and schedules the processing of received service primitives according to priority levels thereof.
Abstract: A configurable protocol engine (CPE) capable of constructing (110) a desired protocol structure (112) according to the received configuration information. In addition, the CPE schedules the processing of received service primitives according to the priority levels thereof. The configuration information may include service requirements (102), indications of hardware and software resources (106, 108), and the required QoS (Quality of Service, 104) level. The CPE may be implemented as software, hardware, or as a combination of both.
44 citations
02 Nov 2003
TL;DR: UbiSensor combines techniques used in wireless microsensors and radio frequency identification resulting a wireless sensor having sensing, data processing, network protocol execution, and energy scavenging capabilities.
Abstract: This paper presents the design and performance measurements of a wireless sensor prototype platform (UbiSensor). UbiSensor combines techniques used in wireless microsensors and radio frequency identification (RFID) resulting a wireless sensor having sensing, data processing, network protocol execution, and energy scavenging capabilities. The platform design is driven by energy consumption minimization of given tasks. A commercially available microcontroller, low power RF transceiver, and power generator circuits are used. The measurements indicate 430 /spl mu/W power consumption in typical operating conditions, using 1 Hz sample and transmit rate, which can be scavenged by a 29 mm/sup 2/ sized solar cell or using a transponder interface circuit in a near proximity to a RFID reader. UbiSensor performance results are promising, but further research is required.
36 citations
TL;DR: TUTWLAN is shown to be suitable for wireless home and office applications and provides flexibility, interoperability and availability of services exceeding the recent QoS proposals that has been accounted at the standardisation bodies for standard wireless technologies.
Abstract: Quality of Service (QoS) support has generally been lacking from WPAN and WLAN technologies, which has motivated the research of TUTWLAN. Design objectives have been relatively simple network architecture and capability to support real time services ranging from sensor data to multimedia streaming. The main TUTWLAN entities for QoS support are the Medium Access Control (MAC) protocol called TUTMAC and TUTWLAN Access Point (AP). The channel access is based on dynamic reservation Time Division Multiple Access (TDMA). TUTWLAN is shown to be suitable for wireless home and office applications. It provides flexibility, interoperability and availability of services exceeding the recent QoS proposals that has been accounted at the standardisation bodies for standard wireless technologies.
25 citations
25 May 2003
TL;DR: This paper presents a modular way to synthesize on-chip interconnection architectures for very large scale integrated (VLSI) systems using generic components that use a standard interface and the functionality of the system can be designed separately from the architecture.
Abstract: This paper presents a modular way to synthesize on-chip interconnection architectures for very large scale integrated (VLSI) systems using generic components. The components use a standard interface and, therefore, the functionality of the system can be designed separately from the architecture. Examples from different ends of the performance and cost spectrum are presented. A bus is a simple interconnection that is still powerful enough for many applications. When larger transmission bandwidths are needed, also a crossbar can be considered. The choice of the utilized network should be based on the requirements of the application. The most important metrics helping the decision process are interconnection area and throughput. A bus network is found to be considerably smaller in area than a crossbar but the throughput of a crossbar is over two times higher in large data transfers. The throughput of the examined complex crossbar is mainly bounded by arbitration latencies.
21 citations
01 Jul 2003
TL;DR: Two optimized implementations of the emerging ITU-T H.26L video encoder are described, the first, medium-optimized version, is implemented in C and the latter, highly optimized version, utilizes both algorithmic and platform-specific optimizations.
Abstract: Two optimized implementations of the emerging ITU-T H.26L video encoder are described. The first, medium-optimized version, is implemented in C and the latter, highly optimized version, utilizes both algorithmic and platform-specific optimizations. Comparisons to a correspondingly optimized H.263/H.263+ implementation are given with the spatial and temporal video quality fixed and the bit rate and complexity varied. On a 733 MHz general-purpose processor, an average encoding speed of 17 frames per second for QCIF sequences is achieved with a 29% reduction in bit rate compared to H.263+. The complexity of H.26L is about 3.4 times more than that of H.263+.
19 citations
30 Jun 2003
TL;DR: This paper proposes a model to maximize revenue while serving customers with different quality-of-service (QoS) requirements based on the weighted fair queue policy, which is extended so that the usage-based revenue criterion can be used to dynamically adapt weights.
Abstract: This paper proposes a model to maximize revenue while serving customers with different quality-of-service (QoS) requirements. A providers' goal is to share resources between active customers to ensure all QoS requirements. At the same time, a provider is interested in maximizing the revenue. Since the amount of active users varies a provider functioning can be optimized by allocating different portions of resources. The proposed model is based on the weighted fair queue policy, which is extended so that the usage-based revenue criterion can be used to dynamically adapt weights. The model is flexible in that different services are grouped into service classes and are given different performance characteristics. It guarantees the QoS requirements and maximizes the revenue by manipulating weights of the WFQ model. The simulation of the proposed model considers a single node with several service classes. It is shown that the total revenue can be significantly improved when compared to a non-adaptive approach.
19 citations
11 May 2003
TL;DR: An adaptive weighted fair queue based algorithm for channel allocation based on the weights in gradient type algorithms that is adapted by using revenue as a target function is presented.
Abstract: Different applications, such as voice over IP and video-on-demand, need different quality of service parameters (e.g., guaranteed bandwidth, delay, and latency) from the networks. The customers with different needs pay different prices to the service provider, who must share resources in a plausible way. In a router, packets are queued using a multi-queue system, where each queue can correspond to one service class. This paper presents an adaptive weighted fair queue based algorithm for channel allocation. The weights in gradient type algorithms are adapted by using revenue as a target function.
17 citations
19 Nov 2003
TL;DR: This paper presents an implementation of a communication generator, named transaction generator, utilized in communication-centric SoC architecture exploration where the objective is to find the optimal hardware allocation, task partitioning, and scheduling with a given application model and architectural requirements.
Abstract: This paper presents an implementation of a communication generator, named transaction generator. It is utilized in communication-centric SoC architecture exploration where the objective is to find the optimal hardware allocation, task partitioning, and scheduling with a given application model and architectural requirements. An application is abstracted with a process network model of computation and architecture is described with characteristic metrics. In addition to accelerating architecture exploration, transaction generator can be used in development, verification and comparison of on-chip communication networks.
30 Jun 2003
TL;DR: An adaptive weighted round robin (WRR) based algorithm for traffic allocation is presented and studied in the single node case and it is shown that it can operate in the nonstationary environments.
Abstract: In the future converged wireless and wired networks will be required to provide support to a number of different types of traffic, each with its own particular characteristics and quality of service parameters including e.g. guaranteed bandwidth, jitter, and latency. The customers of different classes pay different prices to the service provider, who must share resources in a plausible way. Differentiation can be implemented by using a multiqueue system, where each queue corresponds to one service class. In this paper, an adaptive weighted round robin (WRR) based algorithm for traffic allocation is presented and studied in the single node case. The weights in the adaptive gradient type WRR algorithm are updated using revenue as a target function. Due to the adaptive nature of the algorithm, it can operate in the nonstationary environments. In addition, it is nonparametric and deterministic in the sense that any assumptions about call density functions or duration distributions are not made.
14 Dec 2003
TL;DR: Mechanisms that will enable network service providers to optimize their operations and make them economically viable, and to provide sufficient attractions to users of network services that will help smooth spikes in demand and lead to a more efficient utilization of the available resources are explored.
Abstract: This paper explores mechanisms that will enable network service providers to optimize their operations and make them economically viable, and to provide, through pricing, sufficient attractions to users of network services that will help smooth spikes in demand and lead to a more efficient utilization of the available resources Proposed model for charging and traffic allocation is suitable for an integrated service network
01 Jan 2003
TL;DR: This paper analyzes how well 802.11e's QoS properties perform under the different kind of simulation scenarios when packet sizes and channel error rates are varied and studies at the point access network for 3G traffic classes.
Abstract: Seamless interconnection with WLAN 80211 and 3/4G technology is essential for the future wireless environment Supporting quality of service is one of the most important issues in 3/4G In this paper the WLAN QoS standard IEEE 80211e draft is studied at the point access network for 3G traffic classes 80211e is compatible with the layer 2 80211p standard and resembles DiffServ QoS functionality that is proposed to be one of the applied QoS standards in 3/4G networks We analyze how well 80211e's QoS properties perform under the different kind of simulation scenarios when packet sizes and channel error rates are varied
19 Nov 2003
TL;DR: The results indicate that approximately 6600 RISC MOPS is required to encode CIF/4CIF-sized video layers while using frame rate of 30 frames/s and a low-complexity motion estimation algorithm.
Abstract: Computational complexity of MPEG-4 encoder supporting spatial scalability is presented. The encoder is partitioned into atomic functions whose complexities are estimated in terms of millions of RISC like operations per second (MOPS). A detailed listing of arithmetic, logic and control flow operations is given. The complexity estimates are used to identify computationally the most demanding encoding tasks. The results indicate that approximately 6600 RISC MOPS is required to encode CIF/4CIF-sized video layers while using frame rate of 30 frames/s and a low-complexity motion estimation algorithm. Furthermore, encoding both spatial layers with the new H.264/AVC causes computational load of 27000 RISC MOPS.
07 Sep 2003
TL;DR: This paper tries to find out the best packet size and channel error rate combinations for each 3G traffic classes by using different wireless and wired network configurations.
Abstract: In this paper we analyze how well 3G traffic classes can survive with 802.11e's QoS properties, when packet sizes and channel error rates are varied. We try to find out the best packet size and channel error rate combinations for each 3G traffic classes by using different wireless and wired network configurations.
21 Sep 2003
TL;DR: End-to-end QoS issues of the cooperation of the WLAN and 3G are studied and how well 802.11e's QoS properties perform under the different kind of network scenarios when packet sizes and channel error rates are varied is analyzed.
Abstract: The WLAN integrated mobile device is designed to extend the reach of enterprise applications and to create new collaboration environments This means that interconnection with WLAN 80211e and 3G technologies are needed Supporting quality of service is one of the most important issues in 3G In this paper end-to-end QoS issues of the cooperation of the WLAN and 3G are studied We analyze how well 80211e's QoS properties perform under the different kind of network scenarios when packet sizes and channel error rates are varied
21 Sep 2003
TL;DR: The adaptive resource allocation model that is based on the WFQ service policy is proposed and it is shown that the total revenue can be increased due to the allocation of unused resources to more expensive service classes.
Abstract: This paper proposes the adaptive resource allocation model that is based on the WFQ service policy. This model ensures QoS requirements and at the same time tries to maximize a service provider's revenue by manipulating weights of the WFQ policy. The model is flexible in that different network services are grouped into service classes and are given such QoS characteristics as bandwidth and delay. To adjust dynamically weights it is proposed to use the usage-based revenue criterion that enables the allocation of free resource between service classes. The simulation considers a single node with the implemented model that serves several service classes with different QoS requirements and traffic characteristics. It is shown that the total revenue can be increased due to the allocation of unused resources to more expensive service classes. Though the simulation has revealed that certain QoS threshold are violated, the percentage of them is insignificant and can be easily tolerated by many network applications.
TL;DR: Results show that the quality of decoded video can be improved by 1 dB with transparent connections compared to connections designed for general packet data, and a video coding subsystem must have access to the error control in a wireless link for the best quality in varying conditions.
Abstract: An experimental comparison of video protection methods targeted for wireless networks is presented. Basic methods are the data partitioning, reversible variable length coding, and macroblock row interleaving as well as macroblock scattering for packet loss protection. An implementation is described, in which scalable video is protected unequally with forward error correcting codes and retransmissions. Comparisons are performed for simulated wideband code division multiple access channel, and measurements are carried out with wireless local area network, Bluetooth as well as with GSM high speed circuit switched data. For the measurements, point-to-point connections are used. The achieved video quality is examined in our real-time wireless video demonstrator. The performance is measured with peak-signal-to-noise-ratio of received video, data overhead, communication delay, number of lost video frames, and decoding frame rate. Results show that the quality of decoded video can be improved by 1 dB with transparent connections compared to connections designed for general packet data. As a conclusion, a video coding subsystem must have access to the error control in a wireless link for the best quality in varying conditions.
06 Jul 2003
TL;DR: A novel architecture for real-time betting is presented that disposes of the up-front effort and enables frequent bet announcements and placements during an ongoing event by broadcasting announcements, time-stamping and storing the placements locally, and collecting them after the event has been finished.
Abstract: Traditional betting systems do not enable betting in real-time during an event and require decisions and preparations beforehand. In this paper a novel architecture for real-time betting is presented. It disposes of the up-front effort and enables frequent bet announcements and placements during an ongoing event. The novel situation is achieved by broadcasting announcements, time-stamping and storing the placements locally, and collecting them after the event has been finished. While solving the processing problems, the architecture requires reliable cryptographic and physical protection. Currently, e.g. DVB and LAN technologies offer potential platforms for providing the service. The implemented LAN demonstrator has shown that user interfaces have to be simple and bets should not be announced too often. It has also shown that real-time operation makes betting more inspiring.
01 Sep 2003
TL;DR: A custom C-language-based SoC exploration and simulation tool, Discrete Time Network Simulator (DTNS), is used to examine the parallelization of System-on-Chip (SoC) simulation over a network of computers.
Abstract: This paper presents parallelization of System-on-Chip (SoC) simulation over a network of computers. A custom C-language-based SoC exploration and simulation tool, Discrete Time Network Simulator (DTNS), is used to examine the problem. Parallelization is implemented with either CORBA or TCP/IP sockets. The distributed DTNS architecture facilitates the analysis of computation requirements for reasonable distribution. The minimum execution time per distributed process for the parallelization to be profitable is 1.2ms with CORBA and 0.4ms with TCP/IP implementation. These results are based on our networked PCs running the Linux operating system. The same network is used to evaluate this distribution method in case of video encoder SoC simulation.
28 Apr 2003
TL;DR: The results show that when modified data partitioning is utilised, a 125 MHz ARM922T is able to process 178 frames/s, if hardware/software co-optimisation and QCIF format are used.
Abstract: Implementation of a video transcoder for error resilient video is described. The video protection is based on two methods using frequency domain partitioning and modified H263++ data partitioning. Moreover, the transcoder uses multiple data packets to communicate a single video frame to the video decoder. The software-based transcoder is implemented on ARM922T RISC processor embedded in Altera Excalibur EPXA10 chip. Neither of the video protection methods requires pixel domain decoding/re-encoding, which substantially reduces complexity of the transcoder. Suitability to embedded systems is demonstrated by evaluating memory consumption and benchmarking the application. The effect of overhead of video protection on rate-distortion performance is analysed. The results show that when modified data partitioning is utilised, a 125 MHz ARM922T is able to process 178 frames/s, if hardware/software co-optimisation and QCIF format are used.
21 Sep 2003
TL;DR: Through the simulations, it is demonstrated that the presented framework and scheduling algorithms can succeed in enabling differentiated services in global replicated Web systems under different workload levels.
Abstract: In this paper, we try to address how to enable QoS support in global replicated Web systems. To solve this problem, we present a framework for building global replicated Web systems and select/design the scheduling algorithms used in the framework. Through the simulations, we demonstrate that our presented framework and scheduling algorithms can succeed in enabling differentiated services in global replicated Web systems under different workload levels. We also investigate the effects of some important parameters on the performances of our presented framework and scheduling algorithms.
TL;DR: It is shown that the adaptive approach can improve the total revenue obtained by a provider when compared to the non-adaptive approach.
Abstract: This paper presents the simulation and analysis of the adaptive resource allocation model, which was proposed and theoretically considered in our previous works. It relies upon the Weighted Fair Queueing (WFQ) service policy and uses the revenue criterion to adjust weights. The purpose of the proposed model is to maximize a provider's revenue and, at the same time, ensure the required Quality-of-Service (QoS) for end-users. Our previous works provided the theoretical evaluation of the proposed model and considered the single-node case only. This paper presents more realistic network scenario, which includes a set of clients and several intermediate switching nodes with the proposed model. The adaptive and non-adaptive approaches to the WFQ are considered in terms of obtained revenue and state of queues at intermediate nodes. It is shown that the adaptive approach can improve the total revenue obtained by a provider when compared to the non-adaptive approach.
01 Jan 2003
TL;DR: CPMA is shown to decrease considerably the processor-memory bottleneck by widening the memory bandwidth, decreasing the number of memory accesses, and diminishing the significance of memory latency.
Abstract: System-on-chip (SoC) designs with parallel on-chip memories increase the memory bandwidth and feed the processor with only necessary data. This paper presents the implementation of a novel Configurable Parallel Memory Architecture (CPMA) that offers plenty of design and run-time configuration possibilities. CPMA is shown to decrease considerably the processor-memory bottleneck by widening the memory bandwidth, decreasing the number of memory accesses, and diminishing the significance of memory latency.
07 Dec 2003
TL;DR: The analysis considers a single node and it is shown that the QoS can be guaranteed due to the allocation of unused resources to the higher service classes.
Abstract: This paper presents WFQ- based scheduling algorithm that allocates network resources in a fair way by taking into account class of service issues. Presented model is flexible in that different traffic flows are grouped into service classes and are given such QoS characteristics as bandwidth and delay. To adjust dynamically weights it is proposed to use the usage-based revenue criterion that enables the allocation of free resource between service classes. The analysis considers a single node and it is shown that the QoS can be guaranteed due to the allocation of unused resources to the higher service classes.
23 Sep 2003
TL;DR: An algorithm for balancing traffic flows between lightpaths in WDM networks based on classification of the traffic flows and the use of state information of the links and optical cross-connects is presented.
Abstract: In this paper we present an algorithm for balancing traffic flows between lightpaths in WDM networks. The load balancing is based on classification of the traffic flows and the use of state information of the links and optical cross-connects. Higher priority traffic flows are directed to less loaded lightpaths thus providing them with higher throughput and lower transport delay than is available for lower priority flows. The load levels of the lightpaths are tuned dynamically to support the required quality of service. Additionally, the algorithm ensures that the aggregate load of the incoming data flows does not exceed the overall capacity of the parallel lightpaths.
01 Jan 2003
TL;DR: The functionality and implementation of a TUTPIS server targeted for bus operators, which receives real-time information through cellular data network from active buses, processes the received data, and produces different types of reports for TUTpIS users is presented.
Abstract: TUTPIS is a large-scale information system being developed for companies that provide public transport services and their customers. TUTPIS is targeted for national services, concerning taxis, buses, and trains as the main means of conveyance. This paper presents the functionality and implementation of a TUTPIS server targeted for bus operators. The server receives real-time information through cellular data network from active buses, processes the received data, and produces different types of reports for TUTPIS users. An operational TUTPIS server has been implemented. The implementation is made on Linux PCs using the Java 2 Enterprise Edition (J2EE). The TUTPIS server has been evaluated in practice with a limited number of buses in Finland during the fall 2002. In addition, performance testing has been carried out to find out the capacity of TUTPIS platform. These tests have shown that the server provides adequate performance for TUTPIS services. The server development continues by extended functionality for both bus operators and passengers.
26 Aug 2003
TL;DR: A management system for home area networks has been developed to support heterogeneous network technologies, automate the network configuration and management, and to enable application based Quality of Service support.
Abstract: A management system for home area networks has been developed. The main design targets have been to support heterogeneous network technologies, automate the network configuration and management, and to enable application based Quality of Service support. The resulting system architecture has a five-layer functional architecture and a centralised topology with a management server. Also, the support of new proprietary management functionality has been designed for wireless access points and client terminals. A wireless LAN and Java based prototype of the management system is being implemented and its architecture presented.
21 Sep 2003
TL;DR: The use of connection admission control (CAC) algorithm together with scheduler optimizing is considered and simulation results are presented and analyzed to show the accuracy of the use of CAC algorithm.
Abstract: In the current development of all IP networks different traffic classes, which are used for different services will share the same bandwidth resources of the network. For effective usage of the system resources, arrivals for some low priority traffic classes could be rejected in cases when risk of having overload is high. In this paper, the use of connection admission control (CAC) algorithm together with scheduler optimizing is considered. The scheduler is functioning according to the optimal weight allocation for each traffic class, and CAC is based on the current utilization of the scheduler. Also one traffic class, which is referenced as "voice" class has more priority compared to others. For the scheduler optimization, revenue function is considered with linear approximation and the adaptive weights are found based on Lagrangian relaxation. To show the accuracy of the use of CAC algorithm, simulation results are presented and analyzed.