Are mmWave Low-Complexity Beamforming Structures Energy-Efficient? Analysis of the Downlink MU-MIMO
Abstract
Future cellular systems based on the use of above-6 GHz frequencies, the so-called millimeter wave (mmWave) bandwidths, will heavily rely on the use of antenna arrays both at the transmitter and at the receiver, possibly with a large number of elements. For complexity reasons, fully digital precoding and postcoding structures may turn out to be unfeasible, and thus suboptimal structures, making use of simplified hardware and a limited number of RF chains, have been investigated. This paper considers and makes a comparative assessment, both from a spectral efficiency and energy efficiency point of view, of several suboptimal precoding and postcoding beamforming structures for the downlink of a cellular multiuser MIMO (MU-MIMO) system. Based on the most recently available data for the energy consumption of phase shifters and switches, we show that there are cases where fully-digital beamformers may achieve a larger energy efficiency than lower-complexity solutions, as well as that structures based on the exclusive use of switches achieve quite unsatisfactory performance in realistic scenarios.
- Publication:
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arXiv e-prints
- Pub Date:
- October 2016
- DOI:
- 10.48550/arXiv.1610.07240
- arXiv:
- arXiv:1610.07240
- Bibcode:
- 2016arXiv161007240B
- Keywords:
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- Computer Science - Information Theory
- E-Print:
- 6 pages. To be presented at the 2016 GLOBECOM Workshop on Emerging Technologies for 5G Wireless Cellular Networks (ET5G). arXiv admin note: text overlap with arXiv:1607.07234