197 research outputs found

    Integrated Circuit Solutions for High Datarate Polymer Fiber Communication

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    Most societies today are dependent on an Internet connection. It has to be reliable in any condition, energy efficient, but most importantly fast. High data rate communication is urgently needed, not only to connect one part of the world to the other, but also for short range applications to help us get through the day. Communication within an autonomous car, to get us from point A to point B, streaming entertainment at a Friday night, or parts of a production chain to help out at a factory. The transmitters and receivers are key components to transfer the data to make these kind of applications possible. Adjustments to what is available and possible is what challenges the progress. Fundamental limitations comes from the material properties and available energy in comparison to the noise around us. Dealing with bandwidth limitations is somewhat man-made, but the interference of different signals is completely real. Looking around for opportunities in this world leads you to look for free bandwidths. The millimeterwave-band (30-300 GHz) offers available bandwidth as well as other benefits. In this work, different circuit solutions enabling high data rate communication is proposed and presented. Different technologies are used, like state of the art processes and commercial processes. Wirebound communication through polymer microwave fiber (PMF) using energy efficient RF-DAC based modulators and power detectors (PDs) is a cheap and robust solution. In this work we explore the opportunities of short range, ultra high data rate, PMF bound communication, which is found to support 30 Gbps error free (BER<10^-12) data

    Channel Estimation for Delay Alignment Modulation

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    Delay alignment modulation (DAM) is a promising technology for inter-symbol interference (ISI)-free communication without relying on sophisticated channel equalization or multi-carrier transmissions. The key ideas of DAM are delay precompensation and path-based beamforming, so that the multi-path signal components will arrive at the receiver simultaneously and constructively, rather than causing the detrimental ISI. However, the practical implementation of DAM requires channel state information (CSI) at the transmitter side. Therefore, in this letter, we study an efficient channel estimation method for DAM based on block orthogonal matching pursuit (BOMP) algorithm, by exploiting the block sparsity of the channel vector. Based on the imperfectly estimated CSI, the delay pre-compensations and tap-based beamforming are designed for DAM, and the resulting performance is studied. Simulation results demonstrate that with the BOMP-based channel estimation method, the CSI can be effectively acquired with low training overhead, and the performance of DAM based on estimated CSI is comparable to the ideal case with perfect CSI

    Integrated Circuit Design for High Data Rate Polymer Microwave Fiber Communication

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    The rapid development of semiconductor processes with a maximum frequency of oscillation well above 300 GHz enables new applications at frequencies above 100 GHz to be researched and developed. Such applications include wireless backhaul, wireless access, radar and radiometer sensors, wireless energy distribution and harvesting, etc.\ua0For several of these applications, a throughput in data rate well above 10 Gbps, even up to 100 Gbps, is required. Optical fiber communication is the leading option for high data rate and long-range wired communication. However, for shorter ranges like chip-to-chip or module-to-module (up to ten meters), millimeter-wave communication over a polymer microwave fiber (PMF) is an interesting alternative due to its potential low cost. Other advantages include flexibility, less sensitivity to temperature variations, and a more relaxed mechanical tolerance requirement. Similar to optical fiber, dispersion occurs on PMFs and will cause symbol interference. Different ways to deal with this effect are investigated, for example, pulse shaping and equalization of the signal.\ua0This work proposes and presents various circuit solutions enabling high data rate communication. Two technologies are used, 250 nm InP DHBT and 130 nm SiGe BiCMOS. An energy-efficient solution using an RF-DAC and power detector for pulse amplitude modulated links are evaluated, as well as an I/Q modulated solution. I/Q (de-)modulators require more complexity, but the increased spectral efficiency can also increase the data rate further.\ua0\ua0In summary, I explore the opportunities and challenges of short-range, ultra-high data rate, PMF bound communication, which is found to support 56 Gbps error-free (BER<10-12) data and 102 Gbps with a BER=2.1*10-3

    Bandwidth Compressed Waveform for 60 GHz Millimeter-Wave Radio over Fiber Experiment

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    A bandwidth compressed waveform termed spectrally efficient frequency division multiplexing (SEFDM) is experimentally demonstrated in a 60-GHz millimeter-wave (mm-wave) radio-over-fiber scenario to increase transmission data rates without changing signal bandwidth and modulation format. Experimental results show the advantages of SEFDM and confirm that the bit rate of SEFDM signals can be substantially higher than that of orthogonal frequency-division multiplexing (OFDM) signals. Experimentally, a 2.25 Gbit/s 4QAM OFDM signal is transmitted through 250 m of OM-1 multi-mode fiber and then it is optically up converted to 60 GHz band at the photodiode before delivery to a mm-wave antenna for transmission over a 3 meter wireless link. The work demonstrates that when the OFDM signal is replaced by an SEFDM signal using the same modulation format and occupying the same bandwidth, the bit rate can be increased, by a factor of up to 67%, to 3.75 Gbit/s at the expense of a 3-dB power penalty. Additionally, a bandwidth compressed 4QAM SEFDM is shown to outperform an 8QAM OFDM of the same spectral efficiency, thereby verifying that a lower order modulation format may replace a higher order one and achieve performance gain

    An Efficient Uplink Multi-Connectivity Scheme for 5G mmWave Control Plane Applications

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    The millimeter wave (mmWave) frequencies offer the potential of orders of magnitude increases in capacity for next-generation cellular systems. However, links in mmWave networks are susceptible to blockage and may suffer from rapid variations in quality. Connectivity to multiple cells - at mmWave and/or traditional frequencies - is considered essential for robust communication. One of the challenges in supporting multi-connectivity in mmWaves is the requirement for the network to track the direction of each link in addition to its power and timing. To address this challenge, we implement a novel uplink measurement system that, with the joint help of a local coordinator operating in the legacy band, guarantees continuous monitoring of the channel propagation conditions and allows for the design of efficient control plane applications, including handover, beam tracking and initial access. We show that an uplink-based multi-connectivity approach enables less consuming, better performing, faster and more stable cell selection and scheduling decisions with respect to a traditional downlink-based standalone scheme. Moreover, we argue that the presented framework guarantees (i) efficient tracking of the user in the presence of the channel dynamics expected at mmWaves, and (ii) fast reaction to situations in which the primary propagation path is blocked or not available.Comment: Submitted for publication in IEEE Transactions on Wireless Communications (TWC

    Fiber-based broadband wireless access employing optical frequency multiplication

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    Employing optical frequency multiplication, we demonstrate experimentally the simultaneous delivery of different 64QAM radio signals at 5.8 and 17.7 GHz after 4.4 km of multimode fiber in a single radio-over-fiber link. We also propose a flexible mechanism for the dynamic radio link adaptation, and the simultaneous transmission of an in-band control channel with the wireless data channels for power control purposes at the antenna site is demonstrated experimentall

    Position and Orientation Estimation through Millimeter Wave MIMO in 5G Systems

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    Millimeter wave signals and large antenna arrays are considered enabling technologies for future 5G networks. While their benefits for achieving high-data rate communications are well-known, their potential advantages for accurate positioning are largely undiscovered. We derive the Cram\'{e}r-Rao bound (CRB) on position and rotation angle estimation uncertainty from millimeter wave signals from a single transmitter, in the presence of scatterers. We also present a novel two-stage algorithm for position and rotation angle estimation that attains the CRB for average to high signal-to-noise ratio. The algorithm is based on multiple measurement vectors matching pursuit for coarse estimation, followed by a refinement stage based on the space-alternating generalized expectation maximization algorithm. We find that accurate position and rotation angle estimation is possible using signals from a single transmitter, in either line-of- sight, non-line-of-sight, or obstructed-line-of-sight conditions.Comment: The manuscript has been revised, and increased from 27 to 31 pages. Also, Fig.2, Fig. 10 and Table I are adde
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