07-09-2012, 11:41 AM
INSTALLATION OF BASE TRANS EVER STATION AT BANGLALION WIMAX
[attachment=33602]
Basic concept of WiMAX:
WiMAX is short for Worldwide Interoperability for Microwave Access. It is a metropolitan wireless standard created by the companies Intel and Alvarion in 2002 and ratified by the IEEE (Institute of Electrical and Electronics Engineers) under the name IEEE-802.16. More precisely, WiMAX is the commercial designation that the WiMAX Forum gives to devices which conform to the IEEE 802.16 standard, in order to ensure a high level of interoperability among them.
Remote Radio Unit (RRU):
The traditional architecture of the radio infrastructure for cellular systems is based on complete, stand-alone Base Stations, usually realized as fully indoor equipment, connected on one side to the aerial elements, and on the other side to the traffic network. Current technical and commercial trends have originated the development and use of different type of products to properly meet both traffic and coverage requirements of modern cellular networks and to flexibly support their expansion over time. One of the major players is the deployment of Remote Radio Units (RRU) also called Remote Radio Heads (RRH). A Remote Radio Unit is a single unit in which only the RF front-end functionalities are implemented. It is connected to the remaining baseband processing part through a bidirectional link. It greatly reduces the carriers’ requirement for site resources and their investment and meanwhile improves the effect of coverage. In addition, it reduces feeder line loss and supports the cell merge of different RF units, so it can be used in special situations where traditional technology cannot solve problems, for example, the coverage of high-speed railway and ultra-long distance.
High level of Integration, Low Power loss and Small size are the key requirements of a RRU system. TI provides a complete board solution for designing a RRU.TI offers a single chip solution for the transmit path with DUC, CFR, and DPD functionalities all integrated together. This solution also provides excellent thermal dissipation. The Fully Integrated PLL/VCO and IQ Modulator from TI has high linearity and low noise floor.
ESD Precautions
The BTS includes devices that may be damaged by accidental introduction of ground or foreign voltages. Electrostatic discharge on a component at a voltage exceeding 600 Volts may damage the component, even if mounted on a board.
All electronic components used in 4Motion are subject to ESD electrostatic discharges. Electrostatic discharges at voltage ratings below 4000V are not normally detected or perceived in any other form by the persons causing the actual discharges. For example, the natural movements of a person wearing synthetic clothing may generate electrostatic voltages exceeding 10,000V. Components are damaged by an electrical break in the ultra-thin insulating layer in the integrated circuits. The damage may be serious and cause an immediate function failure, or remain latent and occur at a later time.
Lightning Protection Guidelines
This section provides information on the installation of an effective grounding and suppression system, for the protection of Alvarion products against lightning.
The main role of a Grounding System is to minimize lightning damage. This section deals primarily with the grounding of the equipment being installed, however does not describe grounding against lightning, or the grounding of buildings.
Lightning Protection Principles
Lightning protection for Alvarion Outdoor Units (ODU) installed outdoors on towers or poles, is provided by ensuring minimum pickup of lightning induced transients, and by the suppression of transient voltages at the input and output terminals of both the Indoor and Outdoor units. Minimizing the pickup of induced voltages is accomplished by isolating the Outdoor Units and cables from the lightning down current, and through the use of shielded cables with peripheral shield grounding. The outdoor Radio Units and Antennas are connected mechanically to the tower or pole, which is in turn grounded in accordance with the requirements of most safety standards, therefore the Outdoor Units are grounded as well. Isolating the outdoor units from the tower carrying the lightning down current is theoretically appealing, however, when the outdoor units are installed on conducting towers any such isolation will be rendered useless during rain. Therefore, it is recommended to ground the Outdoor Units and the associated shield/signal grounds of the IF/RF cables to the tower or pole, which are grounded themselves in accordance with the requirements of most safety standards. In order to limit the amount of lightning current flowing on the shields of the IF cables, only one grounding point is allowed for the shields to the tower or pole. This is the point where the Outdoor Units are grounded to the pole. This way, the current arriving from the lightning to the earth will prefer the down conductor from the lightning rod or the structure of the tower or pole, rather than the path along the shield, thus protecting the equipment. In addition, the IF Cable shields must be grounded (at the other end) to the entry panel at the facility building.
Air terminal
The Air Terminal is the part of the LPS that intercepts lightning flashes. It blocks the downward-moving stepped leader of the lightning strike, by launching an upward-going attachment spark. Once the attachment is achieved, the bulk of lightning current follows the ionized path. This way, the air terminal diverts the lightning away from personnel and electronic equipment. If an Air Terminal is not installed at the highest point of the tower or pole, the radio element connected to the highest point, usually the antenna is most likely the attachment point.
The Air Terminal must be a steel construction with a pointed tip. Referring to Figure below, the height of the Air Terminal tip above the highest Alvarion element on the tower or pole, typically the antenna, must be at least twice the distance (2 x d) between the outer surface of the antenna and the tower or pole. This will ensure a “protection cone” of 60º around the tower or pole. In areas of high lightning activity, the length (H) should be increased to up to 5 times the distance.
If a remote electrical tilt is used, “d” represents the maximum horizontal distance. The Air Terminal must be welded to the pole structure and connected to a Down Conductor.
Down Conductor3
The Down-Conductor conducts lightning current from the Air Terminal system to the Earth Termination system. The Down Conductor must be straight and vertically installed in order to provide the shortest and most direct path to earth. The formation of bends must be avoided.
[attachment=33602]
Basic concept of WiMAX:
WiMAX is short for Worldwide Interoperability for Microwave Access. It is a metropolitan wireless standard created by the companies Intel and Alvarion in 2002 and ratified by the IEEE (Institute of Electrical and Electronics Engineers) under the name IEEE-802.16. More precisely, WiMAX is the commercial designation that the WiMAX Forum gives to devices which conform to the IEEE 802.16 standard, in order to ensure a high level of interoperability among them.
Remote Radio Unit (RRU):
The traditional architecture of the radio infrastructure for cellular systems is based on complete, stand-alone Base Stations, usually realized as fully indoor equipment, connected on one side to the aerial elements, and on the other side to the traffic network. Current technical and commercial trends have originated the development and use of different type of products to properly meet both traffic and coverage requirements of modern cellular networks and to flexibly support their expansion over time. One of the major players is the deployment of Remote Radio Units (RRU) also called Remote Radio Heads (RRH). A Remote Radio Unit is a single unit in which only the RF front-end functionalities are implemented. It is connected to the remaining baseband processing part through a bidirectional link. It greatly reduces the carriers’ requirement for site resources and their investment and meanwhile improves the effect of coverage. In addition, it reduces feeder line loss and supports the cell merge of different RF units, so it can be used in special situations where traditional technology cannot solve problems, for example, the coverage of high-speed railway and ultra-long distance.
High level of Integration, Low Power loss and Small size are the key requirements of a RRU system. TI provides a complete board solution for designing a RRU.TI offers a single chip solution for the transmit path with DUC, CFR, and DPD functionalities all integrated together. This solution also provides excellent thermal dissipation. The Fully Integrated PLL/VCO and IQ Modulator from TI has high linearity and low noise floor.
ESD Precautions
The BTS includes devices that may be damaged by accidental introduction of ground or foreign voltages. Electrostatic discharge on a component at a voltage exceeding 600 Volts may damage the component, even if mounted on a board.
All electronic components used in 4Motion are subject to ESD electrostatic discharges. Electrostatic discharges at voltage ratings below 4000V are not normally detected or perceived in any other form by the persons causing the actual discharges. For example, the natural movements of a person wearing synthetic clothing may generate electrostatic voltages exceeding 10,000V. Components are damaged by an electrical break in the ultra-thin insulating layer in the integrated circuits. The damage may be serious and cause an immediate function failure, or remain latent and occur at a later time.
Lightning Protection Guidelines
This section provides information on the installation of an effective grounding and suppression system, for the protection of Alvarion products against lightning.
The main role of a Grounding System is to minimize lightning damage. This section deals primarily with the grounding of the equipment being installed, however does not describe grounding against lightning, or the grounding of buildings.
Lightning Protection Principles
Lightning protection for Alvarion Outdoor Units (ODU) installed outdoors on towers or poles, is provided by ensuring minimum pickup of lightning induced transients, and by the suppression of transient voltages at the input and output terminals of both the Indoor and Outdoor units. Minimizing the pickup of induced voltages is accomplished by isolating the Outdoor Units and cables from the lightning down current, and through the use of shielded cables with peripheral shield grounding. The outdoor Radio Units and Antennas are connected mechanically to the tower or pole, which is in turn grounded in accordance with the requirements of most safety standards, therefore the Outdoor Units are grounded as well. Isolating the outdoor units from the tower carrying the lightning down current is theoretically appealing, however, when the outdoor units are installed on conducting towers any such isolation will be rendered useless during rain. Therefore, it is recommended to ground the Outdoor Units and the associated shield/signal grounds of the IF/RF cables to the tower or pole, which are grounded themselves in accordance with the requirements of most safety standards. In order to limit the amount of lightning current flowing on the shields of the IF cables, only one grounding point is allowed for the shields to the tower or pole. This is the point where the Outdoor Units are grounded to the pole. This way, the current arriving from the lightning to the earth will prefer the down conductor from the lightning rod or the structure of the tower or pole, rather than the path along the shield, thus protecting the equipment. In addition, the IF Cable shields must be grounded (at the other end) to the entry panel at the facility building.
Air terminal
The Air Terminal is the part of the LPS that intercepts lightning flashes. It blocks the downward-moving stepped leader of the lightning strike, by launching an upward-going attachment spark. Once the attachment is achieved, the bulk of lightning current follows the ionized path. This way, the air terminal diverts the lightning away from personnel and electronic equipment. If an Air Terminal is not installed at the highest point of the tower or pole, the radio element connected to the highest point, usually the antenna is most likely the attachment point.
The Air Terminal must be a steel construction with a pointed tip. Referring to Figure below, the height of the Air Terminal tip above the highest Alvarion element on the tower or pole, typically the antenna, must be at least twice the distance (2 x d) between the outer surface of the antenna and the tower or pole. This will ensure a “protection cone” of 60º around the tower or pole. In areas of high lightning activity, the length (H) should be increased to up to 5 times the distance.
If a remote electrical tilt is used, “d” represents the maximum horizontal distance. The Air Terminal must be welded to the pole structure and connected to a Down Conductor.
Down Conductor3
The Down-Conductor conducts lightning current from the Air Terminal system to the Earth Termination system. The Down Conductor must be straight and vertically installed in order to provide the shortest and most direct path to earth. The formation of bends must be avoided.