| 1. |
- Albrecht, Steffen, 1971-
(författare)
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Sigma-delta based techniques for future multi-standard wireless radios
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Improvements in process technology and design innovations have resulted in compact and cost effective digital baseband solutions. The radio part, however, has remained a bottleneck in terms of chip area and power consumption as the feature size of analog devices does not directly benefit from scaling. With the addition of yet more standards into emerging products, the requirements of future radios will extend over characteristic performance features into demands of programmable and reconfigurable hardware for radios covering multiple frequency bands. Hence, a guideline in the design of such radios is a large degree of hardware sharing. The thesis investigates the application of sigma-delta modulation to arising multistandard wireless radios. First, it reviews principles in wireless radios, such as selected modulation and access techniques. It also examines several communication standards of personal wireless radios as well as common receiver architectures for their implementation. This is followed by general considerations and background information about sigma-delta modulators. In the third and fourth chapter, implementations to two blocks of a wireless radio receiver system are suggested: An architecture for a frequency synthesizer and an implementation of an analog-to-digital converter. In the first contribution, the thesis develops a novel concept for frequency synthesis that is more suitable for multi-band, multi-standard radio architectures, achieving a large amount of hardware sharing among different wireless standards. As a second pillar, the thesis contributes with the design of a dual-standard sigma-delta modulator for data conversion within a radio receiver. Parts of the work concerning the dual-standard modulator are embodied in a granted swedish patent.
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| 2. |
- Atallah, Jad G., et al.
(författare)
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A CMOS frequency synthesizer for multi-standard wireless devices
- 2003
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Ingår i: Proceedings of the 46th IEEE International Midwest Symposium on Circuits & Systems. - NEW YORK : IEEE. - 0780382943 ; , s. 1138-1141
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Konferensbidrag (refereegranskat)abstract
- This paper presents a CMOS frequency synthesizer for wireless transceivers that support several communication standards namely GSM, WCDMA, IEEE 802.11b, and Bluetooth. The architecture is based on a multi-stage phase-locked loop where each stage differs from the others in the parameters of its charge pump and loop filter. It is designed using mathematical models and refined through simulation using different software tools depending on the required perspective. The architecture and the components presented pave the way to provide a low cost, fully integrated implementation.
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| 3. |
- Atallah, Jad G., et al.
(författare)
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A frequency planning and generation scheme for multi-standard wireless transceivers
- 2005
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Ingår i: 12th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2005. - 9789972611001
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Konferensbidrag (refereegranskat)abstract
- This work presents a novel frequency planning scheme associated with a reference frequency generation scheme that has the potential of providing low phase noise contribution for several wireless standards including DCS1800, WCDMA II and III, DECT, WLAN a/b/g and Bluetooth. The scheme is particularly useful when implemented in future technologies and can be extended to cover newer wireless standards in newer bands of interest. It uses a single multi-band voltage-controlled oscillator (VCO) with switching inductors and high speed dividers directly generating the quadrature outputs. The VCO itself covers the frequency ranges from 4.8GHz to 6GHz and from 6.8GHz to 8GHz. Its phase noise is -136dBc/Hz at 1MHz offset from a center frequency of 1.85GHz. The design is sent for fabrication using 0.18ÎŒm CMOS.
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| 4. |
- Atallah, Jad G., et al.
(författare)
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Future 4G front-ends enabling smooth vertical handovers
- 2006
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Ingår i: IEEE Circuits & Devices. - 8755-3996 .- 1558-1888. ; 22:1, s. 6-15
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Tidskriftsartikel (refereegranskat)abstract
- An overview is given of the most important effects that handover considerations have on the design of multistandard mobile radio transceivers. Focus is on the multitude of design issues and challenges that should be taken into account in the RF/analog front-end part. Topics discussed include the convergence challenge, wireless transceiver design challenge, wireless standards, handover initiation, interworking between GSM and DECT, idle mode issues, possible issues when mobile terminals miss pages, procedure while in active communication in DECT mode, procedure while in active communication in GSM mode, and GSM/WLAN handover.
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| 5. |
- Atallah, Jad G., 1979-
(författare)
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Integrated Frequency Synthesis for Convergent Wireless Solutions
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wireless transceivers combining several standards in one unit are of key importance. In order to reach the ultimate goal of maximizing the performance-to-cost ratio of such modules, a careful study of the target application, the architecture, and the frequency planning is strongly required. One of the most challenging tasks is the implementation of the frequency synthesizer. This challenge is compounded by the traditional technical difficulties in designing frequency synthesizers as well as the new requirements that include multi-standard support. As a result, studying the upper levels of the communication system becomes mandatory in order to frame the requirements of the frequency synthesizer and to provide a viable solution from a user’s perspective for an always-best-connected scenario. Additionally, the study of the upper layers opens up new opportunities for innovation at the lower layers, especially at the physical layer where the view is traditionally restricted by some harsh requirements whose source might not be clear at least for the physical-level designer. The first aim of this work is to provide a holistic view of how an optimum user experience can be achieved and how this affects the design of frequency synthesizers for the next generation networks. The work is heavily based on the existing garden of wireless standards although it can also serve for other applications such as real software-defined radios and dynamic spectrum allocation. As a result, this work cuts a vertical path starting from the best user experience vision down to the physical layer where it expands on the design of the frequency synthesizer. It proposes a wireless front-end solution that can make the vision of an always-best-connected scenario a reality. The architecture is based on a wireless detector called Sniffer that searches for an alternative connection while the main connection is running. Not only is the Sniffer solution viable at the physical level, but it also provides a stepping stone for development towards fully-enabled multi-standard transceivers. After this, and inline with the previous vision, some important frequency synthesizer parameters are pointed out and enhancements on the phase-locked architectures are presented. This includes ways to extend the range of the frequency synthesizer and ways to make the synthesizer adaptable depending on the requirements of the wireless standards. This work leads directly to the implementation of a multi-standard frequency synthesizer where the details of the top-down design procedure are presented at several levels of abstraction. In order to round-up the work, and due to the fact that the requirements of the frequency synthesizer stretch thin the capabilities of the technology used, calibration techniques to increase the yield of such a complicated sub-system are presented, an important step towards first-pass success.
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| 6. |
- Gustafsson, E. Martin I., et al.
(författare)
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A flexible algorithmic ADC for wireless sensor nodes
- 2008
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Ingår i: Proceedings of the 15th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2008. - 9781424421824 ; , s. 1213-1216
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
- Gustafsson, E. Martin I., et al.
(författare)
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Behavioral modeling of a programmable UWB/Bluetooth ADC
- 2007
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Ingår i: 14th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2007. - 9781424413775 ; , s. 1159-1162
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the system level design of a programmable ADC that can cover the bandwidth-accuracy space of UWB and Bluetooth standards by employing a capacitive interpolation flash ADC and a sigma-delta ADC. The system level performance of the ADC architectures has been evaluated, and circuit level specifications have been established, considering the most critical circuit non-idealities. The behavioral simulation results show that the ADC can achieve 30 dB SINAD at 528 MSPS in UWB mode, and 86 dB SINAD at 1 MSPS in Bluetooth mode.
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| 9. |
- Gustafsson, E. Martin I., et al.
(författare)
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Design of a Reconfigurable ADC for UWB/Bluetooth Radios
- 2008
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Ingår i: 2008 Joint IEEE North-East Workshop on Circuits and Systems and TAISA Conference, NEWCAS-TAISA. - New York : IEEE. - 9781424423316 ; , s. 205-208
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Konferensbidrag (refereegranskat)abstract
- This paper presents the circuit implementation of a reconfigurable Analog to Digital Converter (ADC) for UWB and Bluetooth communication standards for mobile terminals. The bandwidth accuracy space is covered through smart configuration of a flexible capacitive interpolation ADC, used as stand-alone in UWB mode and as quantizer of a Sigma Delta ADC in Bluetooth mode. The ADC has been accurately modeled in Matlab/Simulink and then implemented at transistor level in a 180 nm CMOS process in the Cadence environment. The simulation results indicate that the ADC can achieve 30 dB SINAD at 528 MSPS in UWB mode, and 60 dB SINAD at 1 MSPS in Bluetooth mode.
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| 10. |
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