22 research outputs found

    Algorithm-Architecture Co-Design for Digital Front-Ends in Mobile Receivers

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    The methodology behind this work has been to use the concept of algorithm-hardware co-design to achieve efficient solutions related to the digital front-end in mobile receivers. It has been shown that, by looking at algorithms and hardware architectures together, more efficient solutions can be found; i.e., efficient with respect to some design measure. In this thesis the main focus have been placed on two such parameters; first reduced complexity algorithms to lower energy consumptions at limited performance degradation, secondly to handle the increasing number of wireless standards that preferably should run on the same hardware platform. To be able to perform this task it is crucial to understand both sides of the table, i.e., both algorithms and concepts for wireless communication as well as the implications arising on the hardware architecture. It is easier to handle the high complexity by separating those disciplines in a way of layered abstraction. However, this representation is imperfect, since many interconnected "details" belonging to different layers are lost in the attempt of handling the complexity. This results in poor implementations and the design of mobile terminals is no exception. Wireless communication standards are often designed based on mathematical algorithms with theoretical boundaries, with few considerations to actual implementation constraints such as, energy consumption, silicon area, etc. This thesis does not try to remove the layer abstraction model, given its undeniable advantages, but rather uses those cross-layer "details" that went missing during the abstraction. This is done in three manners: In the first part, the cross-layer optimization is carried out from the algorithm perspective. Important circuit design parameters, such as quantization are taken into consideration when designing the algorithm for OFDM symbol timing, CFO, and SNR estimation with a single bit, namely, the Sign-Bit. Proof-of-concept circuits were fabricated and showed high potential for low-end receivers. In the second part, the cross-layer optimization is accomplished from the opposite side, i.e., the hardware-architectural side. A SDR architecture is known for its flexibility and scalability over many applications. In this work a filtering application is mapped into software instructions in the SDR architecture in order to make filtering-specific modules redundant, and thus, save silicon area. In the third and last part, the optimization is done from an intermediate point within the algorithm-architecture spectrum. Here, a heterogeneous architecture with a combination of highly efficient and highly flexible modules is used to accomplish initial synchronization in at least two concurrent OFDM standards. A demonstrator was build capable of performing synchronization in any two standards, including LTE, WiFi, and DVB-H

    SMARAD - Centre of Excellence in Smart Radios and Wireless Research - Activity Report 2008 - 2010

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    Centre of Excellence in Smart Radios and Wireless Research (SMARAD), originally established with the name Smart and Novel Radios Research Unit, is aiming at world-class research and education in Future radio and antenna systems, Cognitive radio, Millimetre wave and THz techniques, Sensors, and Materials and energy, using its expertise in RF, microwave and millimetre wave engineering, in integrated circuit design for multi-standard radios as well as in wireless communications. SMARAD has the Centre of Excellence in Research status from the Academy of Finland since 2002 (2002-2007 and 2008-2013). Currently SMARAD consists of five research groups from three departments, namely the Department of Radio Science and Engineering, Department of Micro and Nanosciences, and Department of Signal Processing and Acoustics, all within the Aalto University School of Electrical Engineering. The total number of employees within the research unit is about 100 including 8 professors, about 30 senior scientists and about 40 graduate students and several undergraduate students working on their Master thesis. The relevance of SMARAD to the Finnish society is very high considering the high national income from exports of telecommunications and electronics products. The unit conducts basic research but at the same time maintains close co-operation with industry. Novel ideas are applied in design of new communication circuits and platforms, transmission techniques and antenna structures. SMARAD has a well-established network of co-operating partners in industry, research institutes and academia worldwide. It coordinates a few EU projects. The funding sources of SMARAD are diverse including the Academy of Finland, EU, ESA, Tekes, and Finnish and foreign telecommunications and semiconductor industry. As a byproduct of this research SMARAD provides highest-level education and supervision to graduate students in the areas of radio engineering, circuit design and communications through Aalto University and Finnish graduate schools such as Graduate School in Electronics, Telecommunications and Automation (GETA). During years 2008 – 2010, 21 doctor degrees were awarded to the students of SMARAD. In the same period, the SMARAD researchers published 141 refereed journal articles and 333 conference papers

    Hardware/Software Co-design for Multicore Architectures

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    Siirretty Doriast

    Flexible Receivers in CMOS for Wireless Communication

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    Consumers are pushing for higher data rates to support more services that are introduced in mobile applications. As an example, a few years ago video-on-demand was only accessed through landlines, but today wireless devices are frequently used to stream video. To support this, more flexible network solutions have merged in 4G, introducing new technical problems to the mobile terminal. New techniques are thus needed, and this dissertation explores five different ideas for receiver front-ends, that are cost-efficient and flexible both in performance and operating frequency. All ideas have been implemented in chips fabricated in 65 nm CMOS technology and verified by measurements. Paper I explores a voltage-mode receiver front-end where sub-threshold positive feedback transistors are introduced to increase the linearity in combination with a bootstrapped passive mixer. Paper II builds on the idea of 8-phase harmonic rejection, but simplifies it to a 6-phase solution that can reject noise and interferers at the 3rd order harmonic of the local oscillator frequency. This provides a good trade-off between the traditional quadrature mixer and the 8- phase harmonic rejection mixer. Furthermore, a very compact inductor-less low noise amplifier is introduced. Paper III investigates the use of global negative feedback in a receiver front-end, and also introduces an auxiliary path that can cancel noise from the main path. In paper IV, another global feedback based receiver front-end is designed, but with positive feedback instead of negative. By introducing global positive feedback, the resistance of the transistors in a passive mixer-first receiver front-end can be reduced to achieve a lower noise figure, while still maintaining input matching. Finally, paper V introduces a full receiver chain with a single-ended to differential LNA, current-mode downconversion mixers, and a baseband circuity that merges the functionalities of the transimpedance amplifier, channel-select filter, and analog-to-digital converter into one single power-efficient block

    SMARAD - Centre of Excellence in Smart Radios and Wireless Research - Activity Report 2011 - 2013

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    Centre of Excellence in Smart Radios and Wireless Research (SMARAD), originally established with the name Smart and Novel Radios Research Unit, is aiming at world-class research and education in Future radio and antenna systems, Cognitive radio, Millimetre wave and THz techniques, Sensors, and Materials and energy, using its expertise in RF, microwave and millimeter wave engineering, in integrated circuit design for multi-standard radios as well as in wireless communications. SMARAD has the Centre of Excellence in Research status from the Academy of Finland since 2002 (2002-2007 and 2008-2013). Currently SMARAD consists of five research groups from three departments, namely the Department of Radio Science and Engineering, Department of Micro and Nanosciences, and Department of Signal Processing and Acoustics, all within the Aalto University School of Electrical Engineering. The total number of employees within the research unit is about 100 including 8 professors, about 30 senior scientists and about 40 graduate students and several undergraduate students working on their Master thesis. The relevance of SMARAD to the Finnish society is very high considering the high national income from exports of telecommunications and electronics products. The unit conducts basic research but at the same time maintains close co-operation with industry. Novel ideas are applied in design of new communication circuits and platforms, transmission techniques and antenna structures. SMARAD has a well-established network of co-operating partners in industry, research institutes and academia worldwide. It coordinates a few EU projects. The funding sources of SMARAD are diverse including the Academy of Finland, EU, ESA, Tekes, and Finnish and foreign telecommunications and semiconductor industry. As a by-product of this research SMARAD provides highest-level education and supervision to graduate students in the areas of radio engineering, circuit design and communications through Aalto University and Finnish graduate schools. During years 2011 – 2013, 18 doctor degrees were awarded to the students of SMARAD. In the same period, the SMARAD researchers published 197 refereed journal articles and 360 conference papers

    Savior: A Reliable Fault Resilient Router Architecture for Network-on-Chip

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    [EN] The router plays an important role in communication among different processing cores in on-chip networks. Technology scaling on one hand has enabled the designers to integrate multiple processing components on a single chip; on the other hand, it becomes the reason for faults. A generic router consists of the buffers and pipeline stages. A single fault may result in an undesirable situation of degraded performance or a whole chip may stop working. Therefore, it is necessary to provide permanent fault tolerance to all the components of the router. In this paper, we propose a mechanism that can tolerate permanent faults that occur in the router. We exploit the fault-tolerant techniques of resource sharing and paring between components for the input port unit and routing computation (RC) unit, the resource borrowing for virtual channel allocator (VA) and multiple paths for switch allocator (SA) and crossbar (XB). The experimental results and analysis show that the proposed mechanism enhances the reliability of the router architecture towards permanent faults at the cost of 29% area overhead. The proposed router architecture achieves the highest Silicon Protection Factor (SPF) metric, which is 24.4 as compared to the state-of-the-art fault-tolerant architectures. It incurs an increase in latency for SPLASH2 and PARSEC benchmark traffics, which is minimal as compared to the baseline router.This work was supported by the Spanish 'Ministerio de Ciencia Innovacion y Universidades' and FEDER program in the framework of the 'Proyectos de I+D d Generacion de Conocimiento del Programa Estatal de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i, Subprograma Estatal de Generacion de Conocimiento' (ref: PGC2018-095747-B-I00).Hussain, A.; Irfan, M.; Baloch, NK.; Draz, U.; Ali, T.; Glowacz, A.; Dunai, L.... (2020). Savior: A Reliable Fault Resilient Router Architecture for Network-on-Chip. Electronics. 9(11):1-18. https://doi.org/10.3390/electronics9111783S118911Borkar, S. (1999). Design challenges of technology scaling. IEEE Micro, 19(4), 23-29. doi:10.1109/40.782564Latif, K., Rahmani, A.-M., Nigussie, E., Seceleanu, T., Radetzki, M., & Tenhunen, H. (2013). Partial Virtual Channel Sharing: A Generic Methodology to Enhance Resource Management and Fault Tolerance in Networks-on-Chip. Journal of Electronic Testing, 29(3), 431-452. doi:10.1007/s10836-013-5389-5Borkar, S. (2005). Designing Reliable Systems from Unreliable Components: The Challenges of Transistor Variability and Degradation. IEEE Micro, 25(6), 10-16. doi:10.1109/mm.2005.110Ali, T., Noureen, J., Draz, U., Shaf, A., Yasin, S., & Ayaz, M. (2018). Participants Ranking Algorithm for Crowdsensing in Mobile Communication. ICST Transactions on Scalable Information Systems, 5(16), 154476. doi:10.4108/eai.13-4-2018.154476Ali, T., Draz, U., Yasin, S., Noureen, J., shaf, A., & Zardari, M. (2018). An Efficient Participant’s Selection Algorithm for Crowdsensing. International Journal of Advanced Computer Science and Applications, 9(1). doi:10.14569/ijacsa.2018.090154Poluri, P., & Louri, A. (2016). Shield: A Reliable Network-on-Chip Router Architecture for Chip Multiprocessors. IEEE Transactions on Parallel and Distributed Systems, 27(10), 3058-3070. doi:10.1109/tpds.2016.2521641Valinataj, M., & Shahiri, M. (2016). A low-cost, fault-tolerant and high-performance router architecture for on-chip networks. Microprocessors and Microsystems, 45, 151-163. doi:10.1016/j.micpro.2016.04.009Kim, J., Nicopoulos, C., Park, D., Narayanan, V., Yousif, M. S., & Das, C. R. (2006). A Gracefully Degrading and Energy-Efficient Modular Router Architecture for On-Chip Networks. ACM SIGARCH Computer Architecture News, 34(2), 4-15. doi:10.1145/1150019.1136487Polian, I., & Hayes, J. P. (2011). Selective Hardening: Toward Cost-Effective Error Tolerance. IEEE Design & Test of Computers, 28(3), 54-63. doi:10.1109/mdt.2010.120Mohammed, H., Flayyih, W., & Rokhani, F. (2019). Tolerating Permanent Faults in the Input Port of the Network on Chip Router. Journal of Low Power Electronics and Applications, 9(1), 11. doi:10.3390/jlpea9010011Wang, L., Ma, S., Li, C., Chen, W., & Wang, Z. (2017). A high performance reliable NoC router. Integration, 58, 583-592. doi:10.1016/j.vlsi.2016.10.016Shafique, M. A., Baloch, N. K., Baig, M. I., Hussain, F., Zikria, Y. B., & Kim, S. W. (2020). NoCGuard: A Reliable Network-on-Chip Router Architecture. Electronics, 9(2), 342. doi:10.3390/electronics9020342Poluri, P., & Louri, A. (2015). A Soft Error Tolerant Network-on-Chip Router Pipeline for Multi-Core Systems. IEEE Computer Architecture Letters, 14(2), 107-110. doi:10.1109/lca.2014.2360686Feng, C., Lu, Z., Jantsch, A., Zhang, M., & Xing, Z. (2013). Addressing Transient and Permanent Faults in NoC With Efficient Fault-Tolerant Deflection Router. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 21(6), 1053-1066. doi:10.1109/tvlsi.2012.2204909Liu, J., Harkin, J., Li, Y., & Maguire, L. P. (2016). Fault-Tolerant Networks-on-Chip Routing With Coarse and Fine-Grained Look-Ahead. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 35(2), 260-273. doi:10.1109/tcad.2015.2459050Runge, A. (2015). FaFNoC: A Fault-tolerant and Bufferless Network-on-chip. Procedia Computer Science, 56, 397-402. doi:10.1016/j.procs.2015.07.226Binkert, N., Beckmann, B., Black, G., Reinhardt, S. K., Saidi, A., Basu, A., … Wood, D. A. (2011). The gem5 simulator. ACM SIGARCH Computer Architecture News, 39(2), 1-7. doi:10.1145/2024716.202471

    2D electronics based on graphene field effect transistors: tutorial for modelling and simulation

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    This paper provides modeling and simulation insights into field-effect transistors based on graphene (GFET), focusing on the devices’ architecture with regards to the position of the gate (top-gated graphene transistors, back-gated graphene transistors, and top-/back-gated graphene transistors), substrate (silicon, silicon carbide, and quartz/glass), and the graphene growth (CVD, CVD on SiC, and mechanical exfoliation). These aspects are explored and discussed in order to facilitate the selection of the appropriate topology for system-level design, based on the most common topologies. Since most of the GFET models reported in the literature are complex and hard to understand, a model of a GFET was implemented and made available in MATLAB, Verilog in Cadence, and VHDL-AMS in Simplorer—useful tools for circuit designers with different backgrounds. A tutorial is presented, enabling the researchers to easily implement the model to predict the performance of their devices. In short, this paper aims to provide the initial knowledge and tools for researchers willing to use GFETs in their designs at the system level, who are looking to implement an initial setup that allows the inclusion of the performance of GFETs.This research was funded by PTDC/EEI-TEL/29670/2017—(POCI-01-0145-FEDER-029670); co-financed by the European Regional Development Fund (ERDF), and through COMPETE 2020, by grant SFRH/BD/137529/2018

    Cervical Neoplasia: Causes and Consequences

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    Adaptive Baseband Pro cessing and Configurable Hardware for Wireless Communication

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    The world of information is literally at one’s fingertips, allowing access to previously unimaginable amounts of data, thanks to advances in wireless communication. The growing demand for high speed data has necessitated theuse of wider bandwidths, and wireless technologies such as Multiple-InputMultiple-Output (MIMO) have been adopted to increase spectral efficiency.These advanced communication technologies require sophisticated signal processing, often leading to higher power consumption and reduced battery life.Therefore, increasing energy efficiency of baseband hardware for MIMO signal processing has become extremely vital. High Quality of Service (QoS)requirements invariably lead to a larger number of computations and a higherpower dissipation. However, recognizing the dynamic nature of the wirelesscommunication medium in which only some channel scenarios require complexsignal processing, and that not all situations call for high data rates, allowsthe use of an adaptive channel aware signal processing strategy to provide adesired QoS. Information such as interference conditions, coherence bandwidthand Signal to Noise Ratio (SNR) can be used to reduce algorithmic computations in favorable channels. Hardware circuits which run these algorithmsneed flexibility and easy reconfigurability to switch between multiple designsfor different parameters. These parameters can be used to tune the operations of different components in a receiver based on feedback from the digitalbaseband. This dissertation focuses on the optimization of digital basebandcircuitry of receivers which use feedback to trade power and performance. Aco-optimization approach, where designs are optimized starting from the algorithmic stage through the hardware architectural stage to the final circuitimplementation is adopted to realize energy efficient digital baseband hardwarefor mobile 4G devices. These concepts are also extended to the next generation5G systems where the energy efficiency of the base station is improved.This work includes six papers that examine digital circuits in MIMO wireless receivers. Several key blocks in these receiver include analog circuits thathave residual non-linearities, leading to signal intermodulation and distortion.Paper-I introduces a digital technique to detect such non-linearities and calibrate analog circuits to improve signal quality. The concept of a digital nonlinearity tuning system developed in Paper-I is implemented and demonstratedin hardware. The performance of this implementation is tested with an analogchannel select filter, and results are presented in Paper-II. MIMO systems suchas the ones used in 4G, may employ QR Decomposition (QRD) processors tosimplify the implementation of tree search based signal detectors. However,the small form factor of the mobile device increases spatial correlation, whichis detrimental to signal multiplexing. Consequently, a QRD processor capableof handling high spatial correlation is presented in Paper-III. The algorithm and hardware implementation are optimized for carrier aggregation, which increases requirements on signal processing throughput, leading to higher powerdissipation. Paper-IV presents a method to perform channel-aware processingwith a simple interpolation strategy to adaptively reduce QRD computationcount. Channel properties such as coherence bandwidth and SNR are used toreduce multiplications by 40% to 80%. These concepts are extended to usetime domain correlation properties, and a full QRD processor for 4G systemsfabricated in 28 nm FD-SOI technology is presented in Paper-V. The designis implemented with a configurable architecture and measurements show thatcircuit tuning results in a highly energy efficient processor, requiring 0.2 nJ to1.3 nJ for each QRD. Finally, these adaptive channel-aware signal processingconcepts are examined in the scope of the next generation of communicationsystems. Massive MIMO systems increase spectral efficiency by using a largenumber of antennas at the base station. Consequently, the signal processingat the base station has a high computational count. Paper-VI presents a configurable detection scheme which reduces this complexity by using techniquessuch as selective user detection and interpolation based signal processing. Hardware is optimized for resource sharing, resulting in a highly reconfigurable andenergy efficient uplink signal detector
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