MIMO and Smart Antennas for Mobile Broadband ... - 4G Americas

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phase errors. For this particular example, random amplitude errors of ±0.5dB and random phase errorsof ±20° were applied simultaneous to each transceiver of an 8-column beamforming antenna array.Figure 35 – Beamforming degradation due to amplitude and phase errors.As can be seen in the patterns in Figure 35, phase and amplitude errors can result in significantbeamforming degradation. The degraded patterns may result in undesirably high side-lobe levels,squinting of the main beam, and degradation in gain, as well as losing the ability to accurately positionnulls. Typical beamforming systems deployed today require that amplitude variations be limited to +/-0.5dB, while phase variations are limited to no more than +/- 5 degrees.Calibration networks for beamforming antennas can be implemented by integrating directional couplerson individual antenna paths. The coupled outputs are then combined and connect to a dedicatedcalibration transceiver. A typical calibration network block diagram for a 4-column beamforming antennaarray is shown below in Figure 36. By selectively powering up individual transceivers, the amplitude andphase characterization of each antenna path can be achieved.4G Americas MIMO and Smart Antennas for Mobile Systems – October 2012 – All Rights Reserved48
Figure 36 – Calibration network block diagram for a 4-column beamforming array.The calibration network shown in Figure 36 allows for periodic automated calibrations. Typically, thesecalibrations would take place at periods of low traffic usage, but essentially can be performed at any time.It is important to note that the power divider network and directional couplers must be carefully designedand calibrated such that they do not contribute additional amplitude and phase errors. These types ofnetworks require careful s-parameter characterization at the factory level to ensure that adequateperformance levels are achieved.For beamforming antennas with additional columns, there will be an obvious increase in cost andcomplexity of the calibration networks. Some lower cost calibration networks have eliminated the needfor couplers, combiners and dedicated calibration transceivers. These lower cost calibration networksexploit the strong mutual coupling of the adjacent antenna columns to establish phase relationshipsbetween columns. A separate calibration transceiver is not required in TDD systems, but instead, themain transceivers are used for calibration activity. While these types of calibration networks are lowercost and lower complexity, they do require more complex algorithms for extracting the calibration data.It is important to note that the amplitude and phase errors are proportional to the operating frequency.Beamforming antenna systems operating at 2.5 GHz and 3.5 GHz will observe phase variationsignificantly higher than for a system operating at 850MHz. These increased errors are due to the naturaltolerance variations of the transmission line paths at higher frequencies.4G Americas MIMO and Smart Antennas for Mobile Systems – October 2012 – All Rights Reserved49
Page 1 and 2: MIMO and Smart Antennasfor 3G and 4
Page 3 and 4: 5 Small Cells and HetNet Deployment
Page 5 and 6: 5) Smart antennas provide the next
Page 7 and 8: toward the ground where the mobile
Page 9 and 10: could then be tailored using mechan
Page 11 and 12: Figure 6 - Antenna technology curre
Page 13 and 14: 1.3 INTEGRATED RADIO/ANTENNAFigure
Page 15 and 16: Figure 10 - Link budget comparison
Page 17 and 18: 1.4 ACTIVE ANTENNA SYSTEM (AAS) TEC
Page 19 and 20: and combinations of carriers that c
Page 21 and 22: example, a rural base station with
Page 23 and 24: eamwidth is typically fixed if area
Page 25 and 26: for flat rural scenarios with large
Page 27 and 28: Figure 22, for unprocessed and fitt
Page 29 and 30: Note that this is likely a general
Page 31 and 32: carrier frequency) limited uplink t
Page 33 and 34: These transmission modes are implem
Page 35 and 36: Code Book 1 Layer 2 Layers0 1√2 1
Page 37 and 38: codebook entry 2 will reduce interf
Page 39 and 40: Trans. ModeAntennaConfig. Figure De
Page 41 and 42: It is important to note that the ga
Page 43 and 44: 5 inputs forming the five beams sho
Page 45 and 46: Figure 32 - Downlink bit rate (left
Page 47: system simulation CDF for the anten
Page 51 and 52: smaller allocation. MU-MIMO transmi
Page 53 and 54: 1D Reconfigurable beam (RET)[tiltin
Page 55 and 56: 3.3 COMPARISON OF RET, 2D, AND 3D R
Page 57 and 58: 3.5 NETWORK OPTIMIZATION VERSUS LOA
Page 59 and 60: Figure 40 - Distribution of the ant
Page 61 and 62: • In this case, reconfigurable be
Page 63 and 64: Figure 43 - Typical cell site showi
Page 65 and 66: 4.2 CURRENT DEPLOYMENTSOne operator
Page 67 and 68: Figure 46 - Common monopole during
Page 69 and 70: Figure 48 - Mast with 11 operators
Page 71 and 72: Figure 50 - Antenna mount with Remo
Page 73 and 74: (a) (b) (c)Figure 52 - Small cell s
Page 75 and 76: 6 MISCELLANEOUS COMMERCIAL AND DEPL
Page 77 and 78: Figure 54AFigure 54BFigure 54 — H
Page 79 and 80: The widely used 65º azimuth antenn
Page 81 and 82: Figure 59 — Mathematical results
Page 83 and 84: Recall that the new rules of thumb
Page 85 and 86: 300∑P60SPR(%) =60P∑300Undesired
Page 87 and 88: --Co-Polarization--Cross-Polarizati
Page 89 and 90: 6.2.2 EFFECTS OF INCORRECT ANTENNA
Page 91 and 92: any third order intermodulation pro
Page 93 and 94: A RRH, also known as a Remote Radio
Page 95 and 96: delays of each transmit path. These
Page 97 and 98: equired at the antenna. In addition
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Figure 72 - Photograph of the const
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These cables, being a stranded cons
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6.6.5 ADVANTAGES OF REMOTE FIBER FE
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Figure 79 - Diplexer.Figure 80 - Tr
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Figure 81 - Hybrid combiningcable l
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ports. Integrated duplexers route t
Page 111 and 112:
Figure 90 - Antenna sharing usingTX
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6.7.13 CONFIGURATIONSThe key elemen
Page 115 and 116:
6.8 INDOOR DISTRIBUTED ANTENNA SYST
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een proven by experiment that a spa
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2600 6 to 9 --Table 7 - Link budget
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Figure 107 - Shannon upper limit ca
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achieve MIMO performance on par wit
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It is evident from the trial that M
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Figure 112 - Example antennas from
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1st Upper Sidelobe Level of the 1st
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H/V TrackingDiscrimination between
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Digital RF converterto LNAPAdigital
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27 Section 7.1 of 3GPP Section 7.1
Page 137 and 138:
51 IST-4-027756 WINNER, D1.1.2 V1.1
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