| 1. |
- Björnson, Emil, Professor, 1983-, et al.
(författare)
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A New Look at Cell-Free Massive MIMO : Making It Practical With Dynamic Cooperation
- 2019
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Ingår i: 2019 IEEE 30TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538681107 - 9781538681114 ; , s. 632-637
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Konferensbidrag (refereegranskat)abstract
- This paper takes a new look at Cell-free Massive MIMO (multiple-input multiple-output) through the lens of the dynamic cooperation cluster framework from the Network MIMO literature. The purpose is to identify and address scalability issues that appear in prior work. We provide distributed algorithms for initial access, pilot assignment, cluster formation, precoding, and combining that are scalable in the sense of being implementable with arbitrarily many users. Interestingly, the suggested precoding and combining outperform conjugate beamforming and matched filtering, respectively, while also being fully distributed.
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| 2. |
- Garcia, Johan, 1970-, et al.
(författare)
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Interactions Between Train Velocity and Cellular Link Throughput - An Extensive Study
- 2019
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Ingår i: 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538681107 - 9781538681114 ; , s. 1-7
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Konferensbidrag (refereegranskat)abstract
- Providing reliable internet connectivity to train passengers can be handled with onboard aggregation routers that use multiple external antennas to simultaneously convey user traffic over multiple links. This work studies the operational characteristics of a large-scale deployment of such a system. The examination focuses on how train velocity is associated with achieved link throughput, and how various interaction effects influence the relationship. A large data set collected over three years is analyzed, indicating that there is a systematic association between train velocity and link throughput that varies over the radio conditions and which is also linked to differences between operators.
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| 3. |
- Le, Mai T. P., et al.
(författare)
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What is the Benefit of Code-domain NOMA in Massive MIMO?
- 2019
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Ingår i: 2019 IEEE 30TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC). - : IEEE. - 9781538681107 - 9781538681114 ; , s. 223-227
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Konferensbidrag (refereegranskat)abstract
- In overloaded Massive MIMO systems, wherein the number K of user equipments (UEs) exceeds the number of base station antennas M, it has recently been shown that non-orthogonal multiple access (NOMA) can increase performance. This paper aims at identifying cases of the classical operating regime K < M, where code-domain NOMA can also improve the spectral efficiency of Massive MIMO. Particular attention is given to use cases in which poor favorable propagation conditions are experienced. Numerical results show that Massive MIMO with planar antenna arrays can benefit from NOMA in practical scenarios where the UEs are spatially close to each other.
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