| 1. |
- Edfors, Ove, et al.
(författare)
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Massive MIMO for 5G: Theory, Implementation and Prototyping
- 2016
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Ingår i: Signal Processing for 5G: Algorithms and Implementations. - Chichester, UK : John Wiley & Sons, Ltd. - 1119116465 - 9781119116462 - 9781119116462 ; , s. 189-230
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Bokkapitel (refereegranskat)abstract
- This chapter presents a flexible platform that supports prototyping up to 20 MHz bandwidth 128-antenna multiple input, multiple output (MIMO). It devotes theory, design, implementation, and prototyping of Massive MIMO for 5G communication systems. The chapter overviews the principles and theory of Massive MIMO. It describes the channel modeling system with a focus on specific phenomena of large scale 3D channels. The chapter discusses the practical implementation aspects of Massive MIMO systems including analog circuit imperfections and digital baseband processing. It describes the design and architecture of building an 128 antenna Massive MIMO testbed. The chapter presents the time synchronization and phase coherency aspects of a Massive MIMO base station. In general, the transmit signals should be chosen such that users receive their own symbols, with suppressed interference caused by the symbols intended for other users. Massive MIMO will play a crucial role in 5G systems as spectral and radiated power effciency become increasingly critical.
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| 2. |
- Harris, Paul V., et al.
(författare)
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Serving 22 users in real-time with a 128-antenna massive MIMO testbed
- 2016
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Ingår i: Proceedings - IEEE International Workshop on Signal Processing Systems, SiPS 2016. - 9781509033614 ; , s. 266-272
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Konferensbidrag (refereegranskat)abstract
- This paper presents preliminary results for a novel 128-antenna massive Multiple-Input, Multiple-Output (MIMO) testbed developed through Bristol Is Open in collaboration with National Instruments and Lund University. We believe that the results presented here validate the adoption of massive MIMO as a key enabling technology for 5G and pave the way for further pragmatic research by the massive MIMO community. The testbed operates in real-time with a Long-Term Evolution (LTE)-like PHY in Time Division Duplex (TDD) mode and supports up to 24 spatial streams, providing an excellent basis for comparison with existing standards and complimentary testbeds. Through line-of-sight (LOS) measurements at 3.51 GHz in an indoor atrium environment with 12 user clients, an uncoded system sum-rate of 1.59 Gbps was achieved in real-time using a single 20 MHz LTE band, equating to 79.4 bits/s/Hz. In a subsequent indoor trial, 22 user clients were successfully served, which would equate to 145.6 bits/s/Hz using the same frame schedule. To the best of the author's knowledge, these are the highest spectral efficiencies achieved for any wireless system to date.
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| 3. |
- Malkowsky, Steffen, et al.
(författare)
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Implementation of Low-latency Signal Processing and Data Shuffling for TDD massive MIMO Systems
- 2017
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Ingår i: ; , s. 260-265
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Konferensbidrag (refereegranskat)abstract
- Low latency signal processing and high throughput implementations are required in order to realize real-time TDD massive MIMO communications, especially in high mobility scenarios. One of the main challenges is that the up-link and down-link turnaround time has to be within the coherence time of the wireless channel to enable efficient use of reciprocity. This paper presents a hardware architecture and implementation of this critical signal processing path, including channel estimation, QRD-based MMSE decoder/precoder and distributed reciprocity calibration. Furthermore, we detail a switch-based router implementation to tackle the stringent throughput and latency requirements on the data shuffling network. The proposed architecture was verified on the LuMaMi testbed, based on the NI SDR platform. The implementation supports real-time TDD transmission in a 128x12 massive MIMO setup using 20 MHz channel bandwidth. The processing latency in the critical path is less than 0.15 ms, enabling reciprocity-based TDD massive MIMO for high-mobility scenarios.
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| 4. |
- Malkowsky, Steffen, et al.
(författare)
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The World's First Real-Time Testbed for Massive MIMO: Design, Implementation, and Validation
- 2017
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Ingår i: IEEE Access. - 2169-3536. ; , s. 9073-9088
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Tidskriftsartikel (refereegranskat)abstract
- This paper sets up a framework for designing a massive multiple-input multiple-output (MIMO) testbed by investigating hardware and system-level requirements such as processing complexity, duplexing mode and frame structure. Taking these into account, a generic system and processing partitioning is proposed which allows flexible scaling and processing distribution onto a multitude of physically separated devices. Based on the given hardware constraints such as maximum number of links and maximum throughput for peer-to-peer interconnections combined with processing capabilities, the framework allows to evaluate available off-the-shelf hardware components. To verify our design approach, we present the Lund University Massive MIMO (LuMaMi) testbed which constitutes the first reconfigurable real-time hardware platform for prototyping massive MIMO. Utilizing up to 100 base station antennas and more than 50 field-programmable gate arrays (FPGAs), up to 12 user equipments are served on the same time/frequency resource using an LTE-like OFDM TDD-based transmission scheme. Field trials with this system show that massive MIMO can spatially separate a multitude of users in a static indoor and static/dynamic outdoor environment.
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| 5. |
- Vieira, Joao, et al.
(författare)
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A flexible 100-antenna testbed for Massive MIMO
- 2014
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Konferensbidrag (refereegranskat)abstract
- Massive multiple-input multiple-output (MIMO) is one of the main candidates to be included in the fifth generation (5G) cellular systems. For further system development it is desirable to have real-time testbeds showing possibilities and limitations of the technology. In this paper we describe the Lund University Massive MIMO testbed – LuMaMi. It is a flexible testbed where the base station operates with up to 100 coherent radio-frequency transceiver chains based on software radio technology. Orthogonal Frequency Division Multiplex (OFDM) based signaling is used for each of the 10 simultaneous users served in the 20 MHz bandwidth. Real time MIMO precoding and decoding is distributed across 50 Xilinx Kintex-7 FPGAs with PCI-Express interconnects. The unique features of this system are: (i) high throughput processing of 384 Gbps of real time baseband data in both the transmit and receive directions, (ii) low-latency architecture with channel estimate to precoder turnaround of less than 500 micro seconds, and (iii) a flexible extension up to 128 antennas. We detail the design goals of the testbed, discuss the signaling and system architecture, and show initial measured results for a uplink Massive MIMO over-the-air transmission from four single-antenna UEs to 100 BS antennas.
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