Wireless Communications

Ultra Wideband Communications based on Massive MIMO and Multi-mode Antennas Suitable for Mobile Handheld Devices

 

Research grant by DFG (German Research Foundation) research focus area SPP 1655 (http://www.wireless100gb.de)

DFG MA 4981/4-1 and HO 2226/14-1:

Ultra-high-speed wireless communications with peak data rates of 100 Gbps and beyond, as targeted in the DFG research focus area SPP 1655, requires an ultra-wide signal bandwidth in conjunction with suitable antennas and advanced baseband processing techniques to increase spectral efficiency and power efficiency simultaneously. In this project proposal, additional constraints arise as our focus is on low-cost low-complexity miniature consumer electronic devices, such as ultrabooks, tablet PCs or smart phones. Both downlink and uplink will be studied, and limited mobility shall be supported. Emphasis is on indoor scenarios.

In order to achieve these goals, interdisciplinary research shall be conducted in the area of antenna design and baseband processing. We concentrate on the frequency range of 6.0 - 8.5 GHz, where the spectral mask is most relaxed in Europe (-41.3 dBm/MHz EIRP). Hence, a spectral efficiency of at least 40 bps/Hz must be achieved, with is a rather challenging goal with respect to miniature devices.

There are two main key concepts to achieve this goal: A novel antenna design and an advanced signal processing concept called massive MIMO.  Concerning the antenna design, the new feature is that multiple modes can be activated per antenna element.  Each mode owns an individual antenna port. Hence, many antenna ports can be realized given just a few antenna elements. This concept can be integrated well into miniature devices and it is easily reconfigurable.

Concerning baseband processing, the main focus is on a transmitter design supporting the flexibility offered by the antennas, as well as an advanced, highly parallel receiver design enabling low-cost implementation.  The limited EIRP, the demanding bandwidth efficiency, as well as the small size and limited computational complexity of the mobile terminal are among the biggest challenges. In massive MIMO, the access point (AP) is equipped with a vast number of antenna elements, whereas the terminal is equipped with a single antenna, preferably.

massive_mimo_concept

UWB massive-MIMO MB-OFDM with transmitter-side beamforming shall be addressed for the downlink. Assuming for example an array with 5 x 5 antenna elements as a design guideline, each supporting 5 modes, 125 antenna ports will result at the AP. In the uplink, UWB massive-MIMO MB-OFDM with diversity reception shall be investigated. On the terminal side, one antenna element with 5 modes will result in 5 antenna ports. In this interdisciplinary approach targeting ultra-high bandwidth efficiencies, the first three project years will focus on fundamental questions.


Publications:

  1. Y. Chen, R. Martens, R. Valkonen, and D. Manteuffel, "Evaluation of adaptive impedance tuning for reducing the form factor of handset antennas," IEEE Trans. Antennas Propagat., vol. 63, no. 2, pp. 703–710, Feb. 2015 DOI
    [Abstract]
     

    In this paper, we evaluate adaptive impedance tuning in combination with intrinsically unmatched antennas in order to reduce the form factor of handset antennas. Thereby, we are able to shrink the size of an antenna element by a factor of four compared to an intrinsically broadband matched antenna while maintaining a similar total efficiency in usage scenarios. The antenna concept is based on an unmatched coupling element in order to obtain a flat impedance behavior, which is relatively insensitive to the user interaction. It enables a broadband adaptive matching by a tunable Π-section network using varactors. The network takes into account the parasitic effects of the impedance detector and the ESD protection circuit.

    [BibTeX]
     
    @ARTICLE{CHEN_IEEE_J_AP_2015,  
    author={Chen, Y. and Martens, R. and Valkonen, R. and Manteuffel, D.}, 
    journal={{IEEE} Trans. Antennas Propagat.}, 
    title={Evaluation of Adaptive Impedance Tuning for Reducing the Form Factor of Handset Antennas}, 
    year={2015}, 
    month=feb, 
    volume={63}, 
    number={2}, 
    pages={703--710}, 
    doi={10.1109/TAP.2014.2378288}, 
    ISSN={0018-926X} 
    }
  2. N. Doose and P. A. Hoeher, "Joint precoding and power control for EIRP-limited MIMO systems," submitted for publication to IEEE Trans. Wireless Comm., 2015.
    [BibTeX]
     
    @ARTICLE{DOOSE_IEEE_WCOM_2016_Submitted,
    author={Doose, N. and Hoeher, P.~A.},
    journal={submitted for publication to {IEEE} Trans. Wireless Comm.},
    title={Joint Precoding and Power Control for {EIRP}-Limited {MIMO} Systems},
    year={2015} 
    }
  3. N. Doose and P. A. Hoeher, "Massive MIMO ultra-wideband communications using multi-mode antennas," in Proc. Int. ITG Conf. on Systems, Communications and Coding (SCC), Hamburg, Feb. 2015, pp. 1–6.
    [BibTeX]
     
    @inproceedings{DOOSE_ITG_SCC_2015,
    author={Doose, N. and Hoeher, P.~A.},
    booktitle = {Proc. Int. ITG Conf. on Systems, Communications and Coding (SCC)},
    location = {Hamburg},
    month = feb,
    pages = {1--6},
    title={Massive {MIMO} Ultra-Wideband Communications Using Multi-Mode Antennas},
    year={2015} 
    }
      
  4. N. Doose and P. A. Hoeher, "On EIRP control in downlink precoding for massive MIMO arrays," in Proc. Int. ITG Workshop on Smart Antennas (WSA), accepted for publication, Munich, Mar. 2016.
    [BibTeX]
     
    @INPROCEEDINGS{DOOSE_ITG_WSA_2016_Submitted,
    author={Doose, N. and Hoeher, P.~A.},
    booktitle={Proc. Int. {ITG} Workshop on Smart Antennas ({WSA}), accepted for publication},
    title={On {EIRP} Control in Downlink Precoding for Massive {MIMO} Arrays},
    year={2016},
    month=mar,
    location={Munich}
    }
  5. M. Damrath, P. A. Hoeher, and G. J. M. Forkel, "Piecewise linear detection for direct superposition modulation," submitted for publication to Digital Communications and Networks, 2015.
    [BibTeX]
     
    @article{DAMRATH_J_DCN_2015_Piece-wise-linear-detection,
    author={Damrath, M. and Hoeher, P.~A. and Forkel, G.~J.~M.},
    title={Piecewise linear detection for direct superposition modulation},
    journal={submitted for publication to Digital Communications and Networks},
    year={2015}
    }
  6. M. Damrath, P. A. Hoeher, and G. J. M. Forkel, "Symbol detection based on Voronoi surfaces with emphasis on superposition modulation," submitted for publication to Digital Communications and Networks, 2015.
    [BibTeX]
     
    @article{DAMRATH_J_DCN_2015_Symbol-detection-voronoi, 
    author={Damrath, M. and Hoeher, P.~A. and Forkel, G.~J.~M.},
    title={Symbol detection based on {Voronoi} surfaces with emphasis on superposition modulation},
    journal={submitted for publication to Digital Communications and Networks}
    year={2015} 
    }
  7. N. Doose, "EIRP-limited beamforming for massive MIMO systems," in Proc. ITG Fachtagung Angewandte Informationstheorie, Stuttgart, Oct. 2015.
    [BibTeX]
     
    @INPROCEEDINGS{DOOSE_ITG_FG_Angwandte_Informationstheorie_2015,
    author={Doose, N.},
    booktitle={Proc. {ITG} Fachtagung Angewandte Informationstheorie},
    title={{EIRP}-Limited Beamforming for Massive {MIMO} Systems},
    year={2015},
    month=oct,
    location={Stuttgart}
    }
     
  8. P. A. Hoeher and N. Doose, "A massive MIMO terminal concept based on small-size multi-mode antennas," Trans. Emerging Telecommunications Technologies, Mar. 2015. Online
    [Abstract]
     

    In this tutorial, a novel variation of massive multiple-input multiple-output (MIMO) is proposed, dubbed multi-mode massive MIMO. A key feature is an advanced antenna design suitable for small-scale user terminals like smartphones. Unlike traditional antenna layouts employing a single-antenna port per antenna element, multiple orthogonal modes shall be excited on a conductive body, like the printed circuit board. This antenna conception is motivated by the theory of characteristic modes for conductive bodies. Each mode can be assigned with an individual antenna port, and all antenna ports can be fed independently. In conjunction with suitable baseband processing, unique features, such as single-mode beamforming, can be exploited. Most importantly, some bottlenecks of conventional massive MIMO in conjunction with single-antenna terminals like single-stream processing on the uplink and pilot contamination on the downlink can be improved. Performance results for a three-port prototype multi-mode antenna support the feasibility of the proposed concept. The terminal concept is suitable in context of the upcoming fifth mobile radio generation (5G) and for ultra-fast (100 Gbps) wireless internet access among other applications. Copyright © 2015 John Wiley & Sons, Ltd.

    [BibTeX]
     
    @article{HOEHER_ETT_2015,
    author = {Hoeher, P. A. and Doose, N.},
    doi = {10.1002/ett.2934},
    url = {http://dx.doi.org/10.1002/ett.2934},
    issn = {2161-3915},
    journal = {{Trans. Emerging Telecommunications Technologies}},
    title = {A massive {MIMO} terminal concept based on small-size multi-mode antennas},
    year = {2015},
    month = mar
    }
  9. T. Hadamik, R. Martens, and D. Manteuffel, "Systematic broadband multiport antenna design based on a characteristic mode analysis," in Proc. 6th COST IC1102 WG Meeting & Technical Workshop, Madrid, Oct. 2014.
    [BibTeX]
     
    @INPROCEEDINGS{HADAMIK_COST_2014,
    author={Hadamik, T. and Martens, R. and Manteuffel, D.},
    title={Systematic Broadband Multiport Antenna Design based on a
    Characteristic Mode Analysis},
    booktitle={Proc. 6th {COST} {IC1102} {WG} Meeting \& Technical Workshop},
    location={Madrid},
    month=oct,
    year={2014}
    }
  10. T. Hadamik, R. Martens, and D. Manteuffel, "A design concept for massive MIMO indoor base stations using the theory of characteristic modes," in Proc. European Conf. on Antennas Propagat. (EUCAP), Apr. 2015.
    [BibTeX]
     
    @INPROCEEDINGS{HADAMIK_EUCAP_2015,
    keywords={own},
    author={Hadamik, T. and Martens, R. and Manteuffel, D.},
    title={A Design Concept for Massive {MIMO} Indoor Base Stations Using the Theory of Characteristic Modes},
    booktitle={{Proc. European Conf. on Antennas Propagat. (EUCAP)}},
    month=apr,
    year={2015}
    }
  11. D. Manteuffel, "Characteristic mode based antenna design – a straight forward approach to small form factor antenna integration," in Proc. European Conf. on Antennas Propagat. (EUCAP), Invited Paper, Apr. 2015.
    [BibTeX]
     
    @INPROCEEDINGS{MANTEUFFEL_EUCAP_2015,
    author={Manteuffel, D.},
    title={Characteristic Mode Based Antenna Design - A Straight Forward Approach to Small Form Factor Antenna Integration},
    booktitle={{Proc. European Conf. on Antennas Propagat. (EUCAP), Invited Paper}},
    year={2015},
    month=apr
    }
  12. D. Manteuffel, "Compact multi mode massive MIMO antennas," in IEEE Int. Workshop on Antenna Technology (iWAT), Invited Paper, Seoul, South Korea, Mar. 2015.
    [BibTeX]
     
    @ARTICLE{MANTEUFFEL_IEEE_J_AP_2015_Submitted_Compact-Multi-Mode-Multi-Element-Antenna-for-Indoor-UWB-Massive-MIMO,
    author={Manteuffel, D. and Martens, R.},
    journal={{submitted to {IEEE} Trans. Antennas and Propagation}},
    title={Compact Multi Mode Multi Element Antenna for Indoor {UWB} Massive {MIMO}},
    year={2015}
    }
  13. D. Manteuffel, N. Doose, and P. A. Hoeher, "Evaluation of a compact antenna concept for UWB massive MIMO," in Proc. German Microwave Conf. (GeMiC), accepted for publication, Bochum, Mar. 2016.
    [BibTeX]
     
    @INPROCEEDINGS{MANTEUFFEL_GeMiC_2016_Submitted,
    author={Manteuffel, D. and Doose, N. and Hoeher, P.~A.},
    booktitle={Proc. German Microwave Conf. ({GeMiC}), accepted for publication},
    title={Evaluation of a Compact Antenna Concept for {UWB} Massive {MIMO}},
    year={2016},
    month=mar,
    location={Bochum}
    }
  14. R. Martens, J. Holopainen, E. Safin, J. Ilvonen, and D. Manteuffel, "Optimal dual-antenna design in a small terminal multi-antenna system," IEEE Antennas Wireless Propagat. Lett., vol. 12, pp. 1700–1703, Dec. 2013. DOI
    [Abstract]
     

    This letter introduces a novel 2.6-GHz multiple-input-multiple-output (MIMO) antenna system for mobile terminals. The antenna structures consist of a broadband main antenna covering most of the LTE-A bands and a narrowband second antenna operating at the 2.6-GHz band. The main antenna is a traditional monopole-type capacitive coupling element (CCE) placed on the short edge of the terminal. The second antenna consists of two out-of-phase fed inductive coupling elements (ICEs) placed on the long edges of the chassis. The main purpose of the letter is to demonstrate that this kind of antenna system offers good performance in terms of electromagnetic (EM) isolation and envelope correlation between the antennas. This has been experimentally verified and is originated on the fact that both antennas excite effectively different orthogonal wavemodes, which is studied with the help of the theory of characteristic wavemodes.

    [BibTeX]
     
    @article{MARTENS_IEEE_J_AWPL_2013,
    author={Martens, R. and Holopainen, J. and Safin, E. and Ilvonen, J. and Manteuffel, D.},
    title={Optimal Dual-Antenna Design in a Small Terminal Multi-Antenna System},
    journal=IEEE_J_AWPL{{IEEE} Trans. Antennas Wireless Propagat. Lett.},
    volume={12},
    pages={1700--1703},
    month=dec,
    year={2013}
    }
  15. R. Martens and D. Manteuffel, "Systematic design method of a mobile multiple antenna system using the theory of characteristic modes," IET Microwaves, Antennas & Propagation, vol. 8, pp. 887–893, 12 Sep. 2014. DOI
    [Abstract]
     

    In this study, the authors present a systematic design method of a three-port multiple-input-multiple-output antenna system for small terminals, such as smart phones based on the selective excitation of orthogonal chassis modes. The underlying idea is based on the theory of characteristic modes (TCM). Selective excitation of these modes is realised by sets of non-resonant inductive coupling elements integrated at predefined positions into the printed circuit board (PCB) layout. Stripline feed networks also integrated within the multi-layer PCB layout care for a good impedance match to 50 Ω. The design method of this antenna system is a straight forward application of the TCM and is therefore of general interest for the design of small terminal antennas. Furthermore, owing to the electrically small couplers that require only limited area at the outer edge of the PCB the method represents an interesting solution with the clear potential to be extended to more ports. The realised prototype resembles the predicted performance very well and therefore proves the applicability of the proposed method.

    [BibTeX]
     
    @article{MARTENS_IET_MAP_2014,
    author = {Martens, R. and Manteuffel, D.},
    title = {Systematic design method of a mobile multiple antenna system using the theory of characteristic modes},
    journal = {{IET} Microwaves, Antennas \& Propagation},
    issue = {12},
    volume = {8},
    year = {2014},
    month = sep,
    pages = {887--893},
    doi = {10.1049/iet-map.2013.0534},
    issn = {1751-8725},
    }
  16. D. Manteuffel and R. Martens, "Compact multi mode multi element antenna for indoor UWB massive MIMO," submitted to IEEE Trans. Antennas and Propagation, 2015.
    [BibTeX]
     
    @ARTICLE{MANTEUFFEL_IEEE_J_AP_2015_Submitted_Compact-Multi-Mode-Multi-Element-Antenna-for-Indoor-UWB-Massive-MIMO,
    author={Manteuffel, D. and Martens, R.},
    journal={{submitted to {IEEE} Trans. Antennas and Propagation}},
    title={Compact Multi Mode Multi Element Antenna for Indoor {UWB} Massive {MIMO}},
    year={2015}
    }
  17. E. Safin and D. Manteuffel, "Reconstruction of the characteristic modes on an antenna based on the radiated far field," IEEE Trans. Antennas Propagat., vol. 61, no. 6, pp. 2964–2971, Jun. 2013. DOI
    [Abstract]
     

    In this paper, we present a method to reconstruct the modal current distribution on an antenna from the radiated far field and general knowledge about the modes involved. The method leads to good results if the radiation mechanism of the antenna can be approximated by the current distribution on a simplified structure. The current distribution of the simplified structure is decomposed into its characteristic modes and the related modal far field is calculated. Assuming that the far field of the actual antenna contains the same modes, their weighting coefficients are calculated by comparing the far field of the actual antenna to the modal far field of the simplified structure. It can be shown that the weighting coefficients of all significant modes can be reconstructed with good accuracy even for complex real structures such as mobile phones.

    [BibTeX]
     
    @ARTICLE{SAFIN_IEEE_J_AP_2013,
    author={Safin, E. and Manteuffel, D.},
    journal={{IEEE} Trans. Antennas Propagat.},
    title={Reconstruction of the Characteristic Modes on an Antenna Based on the Radiated Far Field},
    year={2013},
    volume={61},
    number={6},
    pages={2964--2971},
    doi={10.1109/TAP.2013.2251312},
    ISSN={0018-926X},
    month=jun
    }
  18. Safin, E. and Manteuffel, D., "Manipulation of characteristic wave modes by impedance loading," IEEE Trans. Antennas Propagat., vol. 63, no. 4, pp. 1756–1764, Apr. 2015. DOI
    [Abstract]
     

    The influence of the antenna impedance loading on the characteristic wave modes is investigated and evaluated. It is shown that the eigenvalue behavior of the characteristic modes can be modified by impedance loading at specific positions on the antenna. Thereby, it is possible to manipulate certain modes such that they resonate in the desired frequency band. These modes can then effectively be excited to achieve the desired antenna performance. It is found that using characteristic wave modes leads to better intuitive insight compared to the entire current distribution. Furthermore, we present a definition of the modal efficiency of the characteristic modes, which can be used to take into account the effect of losses in the matching components or the load elements.

    [BibTeX]
     
    @ARTICLE{SAFIN_IEEE_J_AP_2015,
    author={Safin, E. and Manteuffel, D.},
    journal={{IEEE} Trans. Antennas Propagat.},
    title={Manipulation of Characteristic Wave Modes by Impedance Loading},
    year={2015},
    month=apr,
    volume={63},
    number={4},
    pages={1756--1764},
    doi={10.1109/TAP.2015.2401586},
    ISSN={0018-926X}
    }