2.1. Contexto de la papa andina y frutos secos en el Perú
2.1.1 Papas peruanas
Power capacity
Port connector type (e.g. N or DIN)
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Wind load
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10.3.1 Work Band
It is the work band of LTE system. Huawei Agisson is offering antenna product of the following frequency band:
806-960MHz (FDD 850MHz, 900MHz)
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1710-2170MHz (FDD 1800MHz, 2100MHz, AWS and TDD Band 33-37, Band 39)
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2300-2700MHz (TDD Band 38/40 and FDD 2.6G)
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824-960/1710-2180MHz (Dual Band)
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2300-2700/2300-2700MHz (for 4T4R MIMO)
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The only major band not covered by Huawei Agisson is 700MHz band used mainly for US LTE networks.
10.3.2 Antenna Gain
The antenna is a passive device. It can neither strengthen the signal nor transmit signal by itself. It concentrates the power to a direction by changing the combination of oscillators and changing the feeder mode. Gain is a key index for antenna, standing for the capability of concentrating the power to a direction. There are usually two units for antenna gain: dBi and dBd. The relationship between the two units is as the following equation:
0 dBd = 2.15 dBi
dBi: the capability of concentrating power by actual directional antenna (including omnidirectional) compared with
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the isotropic antenna. The i in dBi means isotropic.
dBd: the capability of concentrating power by actual directional antenna (including omnidirectional) compared with
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half-wave dipole antenna. The d in dBd means dipole.
Figure 10-1 Relation between dBi and dBd
The antenna gain is relevant to the number of oscillator units, horizontal and vertical beamwidth.
10.3.3 Antenna Pattern
The pattern is the electromagnetic field of antenna radiation distributed by coordinate along fixed distance.
If the pattern is represented by radiation field strength, it is called field strength pattern.
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If the pattern is represented by power density, it is called power pattern.
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If the pattern is represented by phase, it is called phase pattern.
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In mobile communication, the power pattern is the most common.
The antenna pattern is a cubic figure, usually represented by two patterns which are vertical to each other in a main plane. This is the surface pattern. The surface pattern includes vertical pattern and horizontal pattern. There are also omnidirectional antenna pattern and directional antenna pattern. There are other special directional antennas, such as heart-shaped antenna and 8-shaped antenna.
The directionality of antenna lies in the ranking of oscillators and the variety of feeder phase, similar to the interferometric effect of optics in principium. As a result, the power in some directions is strengthened while the power in some directions is weakened. The lobes of various shapes and zero points form. The lobe with the highest power is the main lobe. The lobes near the main lobe with the second highest power are the first side lobes. The second side lobes are those with the third highest power…. The directional antenna produces a rear lobe. Figure 6-2 shows the horizontal and vertical patterns of directional antenna.
Figure 10-2 Horizontal and vertical patterns of directional antenna
10.3.4 Beamwidth
The beamwidth is also called the half power beamwidth, including horizontal beamwidth and vertical beamwidth. The horizontal beamwidth and vertical beamwidth is the beamwidth between two points where the power is lower 50% (3 dB) than the maximum radiation power. The common horizontal beamwidth of eNodeB antennas includes 360°, 90°, 65°, 60°, and 33°. The common vertical beamwidth of eNodeB antennas includes 6.5°, 7°, 10°, 13°, and 16°.
10.3.5 Relation between Beamwidth and Gain
The antenna concentrates power. It strengthens the power of a direction while reducing the power of other directions.
You can usually reduce the horizontal beamwidth to strengthen the power of a direction. When the antenna gain is fixed, the horizontal beamwidth is in inverse proportion to the vertical beamwidth, with their relation as below:
Wherein, G
• a: the antenna gain in the unit of dBi.
β
• : the vertical beamwidth in the unit of dBi.
θ
• : the horizontal beamwidth in the unit of dBi.
According to the previous formula, if you have known the antenna gain and horizontal, you can calculate the vertical beamwidth.
For example, for an omnidirectional antenna, the gain is 11 dBi, the horizontal beamwidth is 360°, so the vertical beamwidth is calculated as below:
Due to the deficiency of design and manufacturing process, the actual vertical beamwidth of omnidirectional antenna is
usually smaller than the calculated result. The less difference between the two beamwidth, the better the antenna is designed.
Figure 10-3 Relation among antenna gain, vertical beamwidth, and horizontal beamwidth
According to the figure above, when the antenna gain is low, the vertical beamwidth and horizontal beamwidth are usually large. When the antenna gain is high, the vertical beamwidth and horizontal beamwidth are usually small.
In addition, the antenna gain depends on the number of oscillators. The larger the number of oscillators, the higher the gain is and the larger the aperture of antenna (the effective receiving area) is. For an omnidirectional antenna, if the antenna gain increases by 3 dB, the antenna length will double. Therefore, the antenna gain is usually within 11 dBi.
10.3.6 Front-to-rear Ratio
It is the ratio of signal radiation strength of main lobe to that of rear lobe, the difference between the level of side lobe and the maximum beam in the range of rear 180°±30°, a positive value. The front-to-rear ratio of common antennas is between 18 dB and 45 dB.
10.3.7 Upper Side Lobe Suppression
In a cellular network, to improve the efficiency of frequency reuse and reduce the intra-frequency interference with neighbor cells, for shaped-beam antenna, you need lower the upper side lobe that radiates neighbor cells and improve
the D/U ratio (the ratio of strength of useful signal to that of interference signal). The level of the first upper side lobe compared with main lobe shall be smaller than –18 dB. This is invalid to the antennas of macro cell eNodeB.
10.3.8 Polarization Mode
The polarization is a radiation feature for indicating the vector special direction of field strength of electromagnetic wave. If unspecified, the spatial direction of electric field vector usually serves as the polarization direction of electromagnetic wave. The spatial direction of electric field vector is the direction of maximum radiation by antenna.
The electromagnetic wave of which the spatial direction of electric filed vector keeps fixed any time is the linear polarization wave. With the ground as a reference, the polarization of which the direction of electric field vector is parallel to ground is the horizontal polarization wave and polarization of which the direction of electric field vector is vertical to ground is the horizontal polarization wave.
The spatial direction of electric field vector is not always fixed.
If the endpoint trace of electric field vector forms a circle, the polarization wave is circular polarization wave.
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If the endpoint trace of electric field vector forms an ellipse, the polarization wave is elliptical polarization wave.
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The elliptical polarization wave and circular polarization wave have polarization direction.
The electromagnetic wave of different bands caters for different polarization modes for propagation. The mobile communication systems usually choose vertical polarization while the broadcasting systems usually choose horizontal polarization. The elliptical polarization usually applies for satellite communication.
The polarization modes of antennas include the polarization and dual polarization, and they are all linear polarization.
The dual polarization antenna reduces the impact from multi-path attenuation and improves the quality of signals received by the eNodeB by using polarization diversity. The dual polarization antenna in LTE networks usually use ±45°
cross polarization mode.
10.3.9 Down Tilt
The down tilt of antenna is an important means that you can enhance the signal level of serving cell and reduce the interference with other cells. The common down tilt modes include mechanical down tilt, preset electrical down tilt, and adjustable electrical down tilt (RET antenna) as below:
Mechanical down tilt: you adjust the mechanical down tilt by lowering the support.
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Electrical down tilt: you adjust the electrical down tilt by adjusting the phase of oscillators. After the preset
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electrical down tilt is sold out of the factory, the down tilt cannot be adjusted. The adjustable electrical down tilt is adjustable.
You can adjust the mechanical down tilt and electrical down tilt simultaneously.
10.3.10 VSWR (Voltage Standing Wave Ratio)
In mobile communication systems, the VSWR of antenna is 1.5:1 at most. Assume that:
Z
• A: input impedance of antenna Z
• 0: nominal characteristic impedance
So the reflection coefficient is calculated as below:
You can also represent the matching character of port with echo loss as below:
If the VSWR is 1.5:1, the RL is 13.98 dB.
When the input impedance of antenna is not equal to characteristic impedance, the reflected and incident waves form standing wave after overlapping on the feeder. The ratio of the maximum adjacent voltage of standing wave to the minimum adjacent voltage of standing wave is the voltage standing wave ratio (VSWR). If the VSWR is over large, the communication distance will be shortened and the reflected power will return the transmitter. As a result, the power amplifier may be burnt and the communication system will work abnormally.
10.3.11 Port Isolation
For multi-port antennas, such as dual polarization antenna and dual band dual polarization antenna, the isolation must exceed 30 dB when the Rx port is the TX port.
10.3.12 Power Capacity
It is the average power capacity. The antenna comprises of coupling parts, such as matching, balancing, and phase shift, so it can bear a limited power. If the power of a carrier is 20 W and a port of the antenna can support four carriers at most, the maximum input power of antenna is 80 W. therefore, the power capacity per port shall exceed 150 W (in a 65°C ambient temperature).
10.3.13 Input Port of Antenna
To improve the reliability of passive intermodulation and RF connection, the input port of antenna is 7/16 DIN-Female.
Before the antenna is used, there shall be a protective cap over the port to avoid generating oxide or absorbing impurity.
10.3.14 Passive Intermodulation (PIM)
The passive intermodulation is caused by non-linearity of the part when the passive parts like connectors, feeders, antennas, and filters work under high power of multi-carrier. The passive parts are usually considered linear but they may have non-linearity to some degree under high power due to the following factors:
The contact between different metals
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The contact between the same metal with rough surface
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Loose connection
The intermodulation product interferes with communication systems, and especially the intermodulation products in the receiver band have severe impact on the receiving performance of system. As a result, there are strict requirements on the intermodulation feature of passive parts like connectors, cable, and antennas as below:
Passive intermodulation index of connects: ≤ –150 dBc
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Passive intermodulation index of cable: ≤ –170 dBc
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Passive intermodulation index of antenna: ≤ –150 dBc
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10.3.15 Dimensions and Weight of Antenna
To facilitate storage, transport, installation, and safety, the antenna is required to have a size as small as possible and a weight as light as possible when all the electrical specifications are met.
The operators have more and more strict requirements on the dimensions, weight, and outlook of antenna, so you must focus on both the technical and non-technical specifications upon antenna selection. In urban areas, the antenna of eNodeB shall be light, small, and beautiful. In suburban and rural areas, there is no such restriction.
10.3.16 Wind Load
The antennas are usually installed on high buildings or towers. In the littoral areas, the wind is strong with high speed, so the antennas are required to work normally under a wind speed of 36 m/s and to keep complete under a wind speed of 55 m/s.
The antenna can usually resist strong wind. In some windy areas, the antennas are damaged due to unstable tower and pole, so you shall choose the antennas with small surface area.
10.3.17 Work Temperature and Humidity
The antenna of eNodeB shall work in a temperature of –40°C to +65°C and a humidity of 0 to 100%.
10.3.18 Lightning Protection
A direct DC connection of each RF input ports of antenna to the ground is required.
10.3.19 Three-proof Capability
The antenna of eNodeB must capable of damp-proof, salt mist-proof, and leaf mold-proof. For an omnidirectional antenna, it can also be installed bottom up and meet the three-proof capacity.
10.3.20 Camouflaged Antenna Scheme for Sites
A camouflaged antenna is beautiful, hidden, and according with technical requirements. The camouflaged antenna aims to keep consistent with the environment and to avoid being noticed so that the mobile communication project
proceeds smoothly. The camouflaged antenna applies for urban site construction and coverage solutions for top grade residence area.
There are no fixed modes and methods for antenna camouflage. The antenna camouflage changes to flexible forms in different scenarios. The antenna camouflage aims to hidden it in the environment. You can choose proper beautification modes according to the environment for actual installation. The following paragraphs focus on some antenna camouflage schemes.
The antenna camouflage includes the following types:
Customized camouflage
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Outlook camouflage
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Camouflage in special environment
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10.3.21 Customized Camouflage
Some vendors provide special antennas (such as cluster antenna), and these antennas usually include the three-side electrical tilting directional antenna. The customized camouflaged antennas are various in shapes. The application of this camouflage is narrow, because the customized antenna is expensive, as shown in figure below.
Figure 10-4 Outlook of customized camouflaged antennas
Figure 10-5 The bottom chart of antenna
10.3.22 Outlook Camouflage
For outlook camouflage, according to the special installation position of antenna, you need design a scheme that the installed antenna accords with the environment and residents can seldom identify the antenna. Paint the antenna with an ambient color so that the residents take it as ornament of environment, as shown in figure below
Figure 10-6 Painting camouflage
Figure 10-7 Flat panel antennas camouflaged by advertising board and road sign
10.3.23 Antenna Camouflage in Special Environment
Residents are sensitive to antennas in some special scenarios, such as part, community, and indoor areas. Especially in a community, the residents reject installing antennas on the roof.
You can camouflage antennas with the previous methods. In addition, you can use the following methods. In communities or on streets, you can use the flat panel antenna, as the advertising board and road sign shown in figure below.
11 References
3GPP Specification TS 36.101: E-UTRA: User Equipment (UE) radio transmission and reception 3GPP Specification TS 36.104: E-UTRA: Base Station (BS) radio transmission and reception 3GPP Specification TS 36.133: E-UTRA: Requirements for support of radio resource management 3GPP Specification TS 36.141: E-UTRA: Base Station (BS) conformance testing
3GPP Specification TS 36.201: E-UTRA: Long Term Evolution (LTE) physical layer; General description 3GPP Specification TS 36.211: E-UTRA: Physical channels and modulation
3GPP Specification TS 36.212: E-UTRA: Multiplexing and channel coding 3GPP Specification TS 36.213: E-UTRA: Physical layer procedures 3GPP Specification TS 36.214: E-UTRA: Physical layer; Measurements
3GPP Specification TS 36.300: E-UTRA and E-UTRAN: Overall description; Stage 2 3GPP Specification TS 36.304: E-UTRA: User Equipment (UE) procedures in idle mode 3GPP Specification TS 36.306: E-UTRA: User Equipment (UE) radio access capabilities 3GPP Specification TS 36.321: E-UTRA: Medium Acces Control (MAC) protocol specification 3GPP Specification TS 36.322: E-UTRA: Radio Link Control (RLC) protocol specification
3GPP Specification TS 36.323: E-UTRA: Packet Data Convergence Protocol (PDCP) specification 3GPP Specification TS 36.331: E-UTRA: Radio Resource Control (RRC); Protocol specification 3GPP Specification TS 36.401: E-UTRAN: Architecture description
3GPP Specification TS 36.410: E-UTRAN: S1 layer 1 general aspects and principles 3GPP Specification TS 36.420: E-UTRAN: X2 general aspects and principles
V. Erceg, K.V.S. Hari, M.S. Smith, D.S. Baum et al, “Channel Models for Fixed Wireless Applications”, IEEE 802.16.3c-01/29r1, 23 Feb. 2001
FCC: methods for predicting interference from response station transmitters and to response station hubs and for supplying data on response station systems.
GSM/3G and LTE Market update: Global mobile Supplier Association, March, 2011
3GPP TSG RAN TSGR#3(99) 231 Technical Specification Group Meeting #3, Yokohama, 21-23 April 1999 Huawei Interference Analysis and Co-existence Training
Huawei LTE Technology Overview and Introduction Training Huawei LTE InterRAT Handover Management Training Huawei TFR Solution and Performance Training Huawei Genex U-Net Operation Manual
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Consultant:
Wang Tao
Editors-in-chief:
Liu Jinghai, Cheng Tangbai, Yang Bo
Editors:
Lin Guangpu, Dong Fei, Zhong Fanliang, Xu Haihong, Jin Keyou, Xie Guozhu, Li Guoyue, Gao Zhengwei, Zhao Yinghe, Zhang Fan, Hao Guangming, Zhou Dongfei, Ma Guotian, Hu Kangyan, Chen Qi, Wang Mingmin, Zhou Zhibing, Zhao Xinlei, Liu Yingwei, Fang Minxi, Liu Yadong, Fang Minghai, Xiang Rui
Auditors:
Lin Guangpu, Dong Fei, Ying Weimin, He Gang, Tan Zhu