Patent Application
20180131440
The present invention relates generally to cellular communications systems and, more particularly, to antenna line devices used in cellular base station and antenna installations.
Cellular base stations typically include, among other things, one or more radios, baseband units, and antennas. The radio receives digital information and control signals from a baseband unit and modulates this information into a radio frequency (“RF”) signal that is then transmitted through an antenna. The radio also receives RF signals from the antenna and demodulates these signals and supplies them to the baseband unit. The baseband unit processes the demodulated signals received from the radio into a format suitable for transmission over a backhaul communications system. The baseband unit also processes signals received from the backhaul communications system and supplies the processed signals to the radio. A power supply may also be provided that generates suitable direct current (“DC”) power signals for powering the baseband unit and the radio.
In order to increase coverage and signal quality, the antennas in many cellular base stations are located at the top of a tower, which may be, for example, about fifty to two hundred feet tall. Conventionally, the power supply, baseband unit and radio were all located in an equipment enclosure at the bottom of the tower to provide easy access for maintenance, repair and/or later upgrades to the equipment. Coaxial cable(s) were routed from the equipment enclosure to the top of the tower. These coaxial cables carry signal transmissions between the radios and the antennas.
In recent years, a shift has occurred and the radios 24 are now more typically located at the top of the tower 30 in new or upgraded cellular installations. Radios 24 that are located at the top of the tower 30 are typically referred to as “remote radio heads” 24. Using remote radio heads 24 may significantly improve the quality of the cellular data signals that are transmitted and received by the cellular base station as the use of remote radio heads 24 may reduce signal transmission losses and noise. In particular, the coaxial cables 34 that connect radios 24 at the bottom of a tower 30 to antennas 32 at the top of the tower 30 may be 100-200 feet in length or more. The signal losses that may occur when radio signals at the RF frequencies used by cellular systems (e.g., 1.8 GHz, 3.0 GHz, etc.) are transmitted over such extended lengths of coaxial cable 34 may be very significant, because at these frequencies the coaxial cables 34 exhibit skin effect and dielectric losses which are considerably higher than at low frequencies. Because of this loss in signal power, the signal-to-noise ratio of the RF signals may be degraded in cellular base stations 10 that locate the radios 24 at the bottom of the tower 30 as compared to cellular base stations where remote radio heads 24 are located at the top of the tower 30 next to the antennas 32. The signals are typically transmitted between the baseband units 22 and the remote radio heads 24 in digital form over optical fibers.
While the use of tower-mounted remote radio heads 24 and fiber optic cables 38 may increase bandwidth and improve signal quality, this architecture also requires that DC power be delivered to the top of the tower 30 to power the remote radio heads 24 (the antennas 32 may be passive devices that do not require an electrical power feed or may have very low power requirements such that they may be powered by a single small cable that carries control communications to the antennas 32). As shown in
In a typical newly-installed cellular installation, three (or more) antennas 32 are mounted on the tower 30, and six, nine or even twelve remote radio heads 24 may be mounted near the antennas 32 at the top of the tower 30. A first set of jumper cables 46 connect the baseband units 22 and the power supply 26 to the first breakout box 42-1, and a second set of jumper cables 48 connect the second breakout box 42-2 to the remote radio heads 24. Each set of jumper cables 46, 48 may include a plurality of data cables and a plurality of power cables (which in some cases may be combined into a set of composite jumper cables that each include both power and data components). A first end of each jumper cable 46 is terminated into the first breakout box 42-1, and a first end of each jumper cable 48 is terminated into the second breakout box 42-2. At least one jumper cable 48 is connected between the second breakout box 42-2 and each remote radio head 24 to provide power to the remote radio head 24 and to carry uplink and downlink communications between the remote radio head 24 and its associated baseband unit 22 at the bottom of the tower 30.
As described above, cellular base station and antenna installations typically include a base transceiver station (base station), including radio frequency equipment and baseband equipment, that is supported by a ground structure. The base station unit is generally located in relatively close proximity to a support structure, such as a tower, on which one or more cellular antennas are mounted towards the top of the support structure. One or more microwave antennas may be mounted on the support structure to provide, for example, a backhaul communication link between the base station and the core network. In addition to the cellular and/or microwave antennas, other types of devices known as antenna line devices (ALDs) may also be mounted on the support structure and/or the cellular antennas. These ALDs may include, but are not limited to, tower mounted amplifiers (TMAs), remote electrical tilt systems (RETs), antenna sensor devices (ASDs), and frequency scanning modules. The radio frequency equipment in the base station may include a controller for communicating with the ALDs to control their operation and, in the case of ASDs, collect sensor information therefrom. As shown in
ALD communication via the AISG interface uses hard wired cables between ALD devices and the base station and, when DC power is received over the RF feeder path, modulation/demodulation circuitry and bias tees. Such connections use extra cables, connectors, and/or circuits, which may pose reliability risks and/or affect passive intermodulation (PIM) performance. Installing and testing of the AISG connections between the base station and ALDs typically involves the use of handheld controllers, which may be inconvenient and time consuming. Moreover, the AISG standard has evolved relatively slowly and does not support data rates exceeding 9600 baud.
In some embodiments of the inventive concept, a system comprises a controller that is configured to generate a control signal, an antenna, and an antenna line device coupled to the antenna that is configured to receive the control signal via a wireless interface.
In other embodiments, the antenna line device is Internet Protocol (IP) addressable.
In still other embodiments, the system further comprises a wireless modem coupled to the antenna line device, wherein the wireless modem is configured to perform a wireless communication protocol over the wireless interface, the wireless communication protocol comprising one of Zigbee, Z-Wave, 6LowPAN, Thread, WiFi, GSM cellular, 3G cellular, 4G/LTE cellular, 5G/LTE cellular, Sigfox, Neul, and LoRaWAN.
In still other embodiments, the control signal comprises an Antenna Interface Standards Group (AISG) control signal.
In still other embodiments, the antenna line device is configured to receive power from one of a solar cell, rechargeable battery, and hydrogen fuel cell.
In still other embodiments, the antenna line device is an amplifier that is coupled to an output of the antenna. The amplifier is configured to adjust an amplification of a signal received from the output of the antenna responsive to the control signal.
In still other embodiments, the antenna line device is a remote electrical tilt system that is coupled to the antenna. The remote electrical tilt system is configured to adjust at least one of an elevation angle of the antenna and an azimuth angle of the antenna responsive to the control signal.
In still other embodiments, the antenna line device is a sensor that is associated with the antenna. The sensor is configured to collect information that is associated with the antenna, the information comprising at least one of azimuth angle, elevation angle, latitude coordinate, longitude coordinate, Global Positioning System (GPS) coordinates, wind speed, temperature, vibration amplitude, and vibration frequency.
In still other embodiments, the antenna line device is a frequency scanning module that is coupled to the antenna. The frequency scanning module is configured to determine a frequency spectrum in use at the antenna.
In still other embodiments, the antenna line device further comprises a memory and is configured to store a plurality of antenna transmission patterns for the antenna in the memory, the plurality of antenna transmission patterns corresponding to a plurality of elevation angles for the antenna, respectively.
In still other embodiments, the antenna line device further comprises a memory and is configured to store a gain of the antenna, a return loss of the antenna, and/or an isolation of the antenna in the memory.
In still other embodiments, the antenna line device is further configured to receive the control signal over the Internet.
In still other embodiments, the controller is a ground-based controller. The antenna is coupled to the ground-based controller at a bottom end of the antenna and the antenna line device is coupled to the antenna at a top end of the antenna.
In further embodiments of the inventive concept, a method comprises establishing, at an antenna line device, an Internet Protocol (IP) connection with a controller and receiving, at the antenna line device, a control signal from the controller, the control signal being associated with an antenna coupled to the antenna line device.
In still further embodiments, the antenna is coupled to a base station and the controller is disposed apart from the base station.
In still further embodiments, receiving the control signal from the controller comprises receiving, at the antenna line device, the control signal from the controller over the Internet.
In other embodiments, of the inventive concept, a method comprises establishing Internet Protocol (IP) connections with a plurality of antenna line devices, the plurality of antenna line devices being coupled to a plurality of antennas, respectively, receiving an plurality of antenna transmission patterns from the plurality of antenna line devices, respectively, each respective antenna transmission pattern being based on an elevation angle of the antenna and an azimuth angle of the antenna, receiving a plurality of geographic location coordinates for the plurality of antennas, respectively, and generating a signal coverage map based on the plurality of antenna transmission patterns and the plurality of geographic location coordinates that indicates geographic areas covered by the plurality of antenna transmission patterns.
In still other embodiments, a first one of the plurality of antennas is associated with a first cellular service provider and a second one of the plurality of antennas is associated with a second cellular service provider that is different from the first cellular service provider.
In still other embodiments, each of the plurality geographic location coordinates comprises a latitude coordinate and a longitude coordinate.
In still other embodiments, each of the plurality of geographic location coordinates comprises Global Positioning System (GPS) coordinates.
It is noted that aspects described with respect to one embodiment may be incorporated in different embodiments although not specifically described relative thereto. That is, all embodiments and/or features of any embodiments can be combined in any way and/or combination. Moreover, other apparatus, methods, systems, and/or articles of manufacture according to embodiments of the inventive subject matter will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional apparatus, systems, methods, and/or articles of manufacture be included within this description, be within the scope of the present inventive subject matter, and be protected by the accompanying claims. It is further intended that all embodiments disclosed herein can be implemented separately or combined in any way and/or combination.
While cellular base stations that use remote radio heads and fiber optic cabling runs up the tower may exhibit improved performance, there are a number of potential difficulties with this architecture. For example, one common problem is that the trunk cable that is delivered to a cellular site may turn out to be too long or too short. If too short, the base station installation may be delayed significantly while waiting for a replacement cable. If too long, it may be necessary to-provide slack cable storage with an appropriate bend radius, which can also complicate and/or delay the installation. To reduce or prevent these delays, wireless operators or their distributors may find it necessary to stock multiple lengths of cable in order to ensure that the correct cable is always available for installation. Other problems include discarded cable in the event of connector damage, difficulties in field terminating the jumper cables, ensuring that all of the jumper cables remain within their specified bend radii, the need to carefully clean the fiber optic connectors in the field, and field testing of the complete fiber optic link.
Additionally, in the above described architecture, it is necessary to connect the jumper cables at the top of the tower between the second break-out box and the remote radio heads. Typically, this is accomplished by opening the second breakout box once it is installed at the top of the tower and connecting the jumper cables to connectors in the second breakout box that receive the optical fibers and power conductors of the trunk cable. This work may be performed under cramped conditions, tens or hundreds of feet above the ground, under a variety of different environmental conditions (e.g., wind, rain, extreme heat, etc.). As such, the jumper cable connection process may be error prone and potentially very dangerous, as a fall from a cellular tower is almost always a fatal event. Accordingly, the need to terminate the jumper cables into the second break-out box at the top of the tower may significantly increase the cost and complexity of the initial installation of the cellular equipment.
Pursuant to embodiments of the present invention, “wireless jumpers” are provided that wirelessly connect a cable termination of a trunk cable that is located at the top of a cellular base station tower to a plurality of remote radio heads that are likewise located atop the tower. A “wireless jumper” refers to a wireless data connection and/or a wireless power connection that are provided between the trunk cable termination and a remote radio head or other tower-mounted equipment. The use of wireless jumpers may greatly simplify the installation of the equipment at the top of the tower.
Additionally, the use of wireless jumpers may allow sending higher voltage power signals up the power cable portion of the trunk cable. Remote radio heads may have high voltage and current requirements, such as, for example, being required to supply 20 Amperes of current at about 50 Volts DC. Cellular base station towers may also be hundreds of feet tall, and hence these power levels must be supplied over hundreds of feet of power cable. Unfortunately, when DC power is delivered over a transmission line such as a power cable, a power loss occurs that is a function of the current level of the DC power signal and the resistance of the power cable. Since the resistance may be significant over hundreds of feet of cable, high power losses can be expected when delivering DC power to the top of cellular towers. This power loss increases the cost of operating the cellular base station.
In some embodiments of the present invention, the use of wireless jumpers allow the breakout boxes that are conventionally used with trunk cables to be replaced with cable terminations that may be, in some embodiments, attached to each end of a trunk cable and permanently sealed at the factory, as the use of wireless jumpers avoids any need to connect jumper cables to connectors that are located within conventional breakout boxes. Typically, the voltage of the power signal that is carried up the power cable to the top of the tower is limited because of safety concerns and/or regulations to less than 100 Volts (e.g., 80-90 Volts) to reduce the risk that technicians may be electrocuted when connecting conventional jumper cables between a breakout box and the remote radio heads. If sealed trunk cable terminations and wireless jumpers are used instead of conventional breakout boxes and jumper cables, then much higher voltage power signals may be transmitted up the power cable. As the power loss is a function of the current, which in turn is inversely proportional to the voltage, the power loss can be reduced by the use of higher voltage power signals. Thus, the use of the wireless jumpers according to embodiments of the present invention may also reduce the power losses associated with powering remote radio heads at the top of a cellular tower or remote radio heads that are at the ends of long horizontal runs such as in tunnel and/or metro-cell applications.
Remote radio heads typically are designed to be powered by a DC power source. As discussed below, wireless power transmission usually (but not always) is performed using AC power signals. Accordingly, in some embodiments of the present invention, the remote radio heads may be designed to be powered by an AC power supply signal. In other embodiments, a DC power supply signal may be transmitted to the wireless jumper, converted to an AC power supply signal, transmitted over the wireless jumper, and then converted back to a DC power supply signal that is used to power the remote radio head. In still other embodiments, an AC power supply signal may be transmitted to and through the wireless jumper, and may then be converted to a DC power supply signal that is used to power the remote radio head. In still other embodiments, DC wireless power transmission techniques may be used (e.g., a laser powered by a DC power source that shines light on a photovoltaic cell) to wirelessly transmit a DC power supply signal.
The wireless jumpers according to embodiments of the present invention may comprise a duplex wireless data connection between the trunk cable termination that is located at or near the top of the tower and each remote radio head. Typically, the data connection between a baseband unit and a remote radio head must support data rates from about 1 Gigabit/second to about 9 Gigabits/second. Any suitable wireless communications technology may be used to implement this wireless data connection including, for example, an IEEE 802.11ad wireless local area network that provides for wide bandwidth, high data rate, low power communications in the 60 GHz frequency band. Other millimeter wave wireless data applications that support the data rate requirement for the remote radio heads may alternatively be used. The tower-mounted trunk cable termination may include one or more wireless transceivers that communicate with respective wireless transceivers that are provided at each remote radio head to implement these wireless data connections. The trunk cable termination may likewise include optical-to-electrical converters and electrical-to-optical converters that place the uplink data in proper form for wireless transmission to the remote radio head and which place the downlink data received over the wireless jumper from the remote radio head in condition for transmission to the baseband unit over a fiber optic cable. In some embodiments, the remote radio heads may be modified to not include an optical transceiver and to instead just contain the wireless transceiver. This may eliminate one data conversion step, thereby simplifying operations and eliminating one possible point of noise contamination.
The wireless power transmission may be carried out in a variety of ways including, for example the use of electromagnetic coupling, electrostatic coupling, resonant electromagnetic induction, microwave power transmission, laser power transmission, etc. The wireless coupling of the power signal may be directional to provide improved efficiency. In some embodiments, the remote radio heads may be located in close proximity to the tower-mounted trunk cable termination to further improve the efficiency of the wireless power transmission.
Embodiments of the present invention will now be discussed in more detail with reference to
Each remote radio head 124 receives digital information and control signals from a respective one of the baseband units 122 over a fiber optic data cable 138 that is part of the trunk cable 140 that is routed from the enclosure 120 to the top of the tower 130. Each remote radio head 124 modulates this information into a radio frequency (“RF”) signal that is then transmitted through a respective one of the antennas 132. Each remote radio head 124 also receives RF signals from a respective one of the antennas 132 and demodulates these signals and supplies them to its respective baseband unit 122 over the fiber optic data cable 138. The baseband unit 122 processes the demodulated signals received from the remote radio head 124 and forwards the processed signals to a backhaul communications system (not shown). The baseband unit 122 also processes signals received from the backhaul communications system and supplies them to the remote radio head 124.
As shown in the callout in
The fiber optic data cable 138 may include a plurality of optical fibers (not visible in
Wireless jumpers are used at the top of the tower 130 to transmit the data and power supply signals between the second cable termination 142-2 and the remote radio heads 124. These wireless connections are illustrated in
The data cable 220 may comprise, for example, a fiber optic cable 220 that includes a plurality of optical fibers 222 and other components such as strength fibers 224, a buffer tube 226 and a jacket 228. The power cable 210 and the data cable 220 may be contained within a common protective jacket 204.
The second cable termination 230-2 may comprise, for example, a factory-sealed enclosure 232 that receives the hybrid cable 202 through an aperture 234 on one side of the enclosure 232. The remote radio heads 124 will typically be positioned on different sides of the enclosure 232. The pairs 216 of conductors 212, 214 of the power cable 210 may be separated within the enclosure 232, and each pair 216 may be routed to a different side of the enclosure 232 that is adjacent one of the remote radio heads 124 to provide a power connection to the respective remote radio head 124.
As discussed above, a wireless power connection may be used to transmit the power supply signal between each pair of conductors 212, 214 and a respective one of the remote radio heads 124. Accordingly, a wireless power transmission device 236 may be connected to each conductor 212. Likewise, a wireless power reception device 238 may be coupled to each conductor 214. The wireless power transmission and reception devices 236, 238 may couple a power supply signal to corresponding wireless power transmission and reception devices 236, 238 that may be provided at each remote radio head 124 (not shown in
As noted above, remote radio heads 124 typically are designed to be powered by a DC power source. However, most wireless power transmission techniques couple AC as opposed to DC power supply signals. Accordingly, in some embodiments of the present invention, the remote radio heads 124 may be designed to be powered by an AC power supply signal, and the power supply 126 may output an AC power supply signal that is transmitted to the second cable termination 230-2 for wireless transmission to a remote radio head 124. In other embodiments, a DC power supply signal may be transmitted to the second cable termination 230-2, where it is converted to an AC power supply signal by a DC-to-AC power conversion circuit. The DC-to-AC power conversion circuit may, for example, be part of the wireless power unit 236/238. The second cable termination 230-2 wirelessly transmits this AC power supply signal to the remote radio head 124, where it is converted back to a DC power supply signal by a corresponding AC-to-DC conversion circuit in the remote radio head 124. In still other embodiments, an AC power supply signal may be transmitted from the power supply 126 to the second cable termination 230-2 where it is wirelessly transmitted to the remote radio head 124. The remote radio head 124 may again include an AC-to-DC power conversion circuit that converts this AC power supply signal to a DC power supply signal that is used to power the remote radio head 124. It will be appreciated that in embodiments which include AC-to-DC or DC-to-AC power conversion, such power conversion will be done on both the positive and negative legs of the circuit. In still other embodiments, techniques may be used to wirelessly transmit a DC power supply signal so that AC-to-DC or DC-to-AC power conversion is not necessary.
The wireless power connection may be implemented in a variety of different ways. For example, in some embodiments, electromagnetic induction may be used to transmit the power supply signal between each pair of power conductors 212, 214 and a corresponding pair of power conductors in each respective remote radio head 124. As shown in
The application of resonance may increase the transmission range for wireless power transmission. For example, with reference to the embodiment of
In other embodiments, the wireless power transmission may be performed via electrostatic induction (i.e., capacitive coupling). As shown in
Microwave power transmission may be used in still other embodiments. With this approach, the wireless transmission device 236 may comprise a radio and an antenna that are used to convert the power supply signal into a microwave signal that is transmitted to the wireless reception device 238. The wireless reception device 238 then converts the received microwave signal back into a power supply signal. Microwave power transmission may exhibit very high efficiencies as compared to other forms of wireless power transmission.
In yet another approach, power may be wirelessly transmitted by converting electrical energy into a laser beam or other light source that is pointed at a photovoltaic cell that is used to convert the received light from the laser beam into an electrical power signal. Magnetic beam forming is another approach that may be used. With this approach, a magnetic beam or wave may be generated at a source and directed (wirelessly) at a magnetic metal that is located at the target. The magnetic beam may induce a vibration in the magnetic metal, and this mechanical energy may be converted into electrical power.
In addition to the wireless power connection, a wireless data connection may be provided between each remote radio head 124 and the second cable termination 230-2. As shown in
In some embodiments, a plurality of mated pairs of transceivers 260 may be provided at the top of the tower 130, with one transceiver 260-1 of each pair located in the second cable termination 230-2 and the other transceiver 260-2 of each pair associated with a respective one of the remote radio heads 124. In such an embodiment, each transceiver 260 of a pair can be assigned a particular frequency sub-band such that the transceivers 260 of the pair only transmit and receive signals in the assigned frequency sub-band. Each pair may be assigned to a different, non-overlapping frequency sub-band so that the wireless transmissions between the second cable termination 230-2 and the remote radio heads 124 do not interfere with each other.
In other embodiments, a single wireless transceiver 260-1 may be provided in the second cable termination 230-2, and all of the uplink and downlink optical fibers 222 may be connected to this single wireless transceiver 260-1. Appropriate multiple access techniques such as, for example, frequency division multiple access (“FDMA”) techniques, time division multiple access (“TDMA”) techniques and/or FDMA/TDMA techniques may be used to ensure that the uplink data carried by each uplink optical fiber 222 is received at the correct remote radio head 124, and to likewise ensure that the received downlink data is delivered to the appropriate baseband unit 122. In still other embodiments, spread spectrum multiple access techniques may be used. The transceivers 260-1, 260-2 may support data rates which may be sufficient to carry the full uplink and downlink transmissions between the remote radio heads 124 and the second cable termination 230-2. It will be appreciated that any appropriate wireless transmission technique may be used to form the wireless jumper for data transmission.
In still other embodiments, the transceivers 260 in the second cable termination 230-2 and in the remote radio heads 124 may have highly directional beamforming capabilities so that the transceiver pairs may transmit in the same frequency band but avoid interference via spatial diversity. In one example embodiment, each of the transceivers 260 in the second cable termination 230-2 and in the remote radio heads 124 may include a phased array antenna. The phased array antennas of the transceivers 260-1 in the second cable termination 230-2 may be generally pointed in one of three directions, so that each phased array antenna in the second cable termination 230-2 is generally pointed in the direction of a corresponding remote radio head 124. Likewise, the wireless transceivers 260-2 in the remote radio heads may all have phased array antennas that generally point towards the second cable termination 230-2.
In some embodiments, a calibration process may be used to determine the weights used on each radiating element of the phased array. For example, the phased array antenna on the first transceiver 260-1 of a transceiver pair may start by sending out a broad-beam signal that is received by the second transceiver 260-2 of the pair. The first transceiver 260-1 then sends out a second signal using a narrower beam that covers, for example the right-half of the first beam, and then sends out a third signal that covers the left half of the first beam. The second transceiver 260-2 of the pair determines which of the second and third signals is stronger, and notifies the first transceiver 260-1 of the pair as to which received signal was stronger. The first transceiver 260-1 then repeats this process by sending out two additional signals, one for each half of the beam associated with the stronger received signal. By this process, the beam of the phased array antenna of the first transceiver 260-1 of the pair may be progressively narrowed so that a narrow beam is formed that points directly at the second transceiver 260-2 of the pair. This calibration process may be performed for each of the phased array antennas in order to implement spatial diversity so that all of the transceivers can transmit and receive signals in the same frequency band. Various methods for implementing beamsteering are discussed, for example, in an article by Abbas Abbaspour-Tamijani and Kamal Sarabandi available at http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.132.8520&rep=rep1&type=pdf and in an article available at http://www.ece.ucsb.edu/wcsl/Publications/eric_itwc2011.pdf, each of which is incorporated herein by reference.
Referring again to
As shown in
As shown in
As shown in
Pursuant to further embodiments of the present invention, wireless jumpers may be used to reduce power losses associated with delivering a power signal to the remote radio heads 124.
The DC voltage of a power signal that is supplied to a remote radio head from a power supply over a power cable may be determined as follows:
V
RRH
=V
PS
−V
Drop (1)
where VRRH is the DC voltage of the power signal delivered to the remote radio head, VPS is the DC voltage of the power signal that is output by the power supply, and VDrop is the decrease in the DC voltage that occurs as the DC power signal traverses the cabling from the power supply to the remote radio head. VDrop may be determined according to Ohm's Law as follows:
V
Drop
=I
RRH
*R
Cable (2)
where RCable is the electrical resistance (in Ohms) of the power cable connecting the power supply to the remote radio head and IRRH is the average current (in Amperes) flowing through the power cable to the remote radio head.
The electrical resistance RCable of the power cable is inversely proportional to the diameter of the conductor of the power cable. Thus, the larger the diameter of the conductor (i.e., the lower the gauge of the conductor), the lower the resistance of the power cable. Typically, power cables utilize copper conductors due to the low resistance of copper. Copper resistance is specified in terms of unit length, typically milliohms (mΩ)/ft for a specified cross-sectional area; as such, the cumulative electrical resistance of the power cable increases with the length of the cable. Thus, the longer the power cable, the higher the voltage drop VDrop.
Typically, a minimum required supply voltage, a nominal or recommended supply voltage and a maximum supply voltage will be specified for the remote radio head. Thus, the power supply must output a voltage VPS such that VRRH will be between the minimum and maximum supply voltages of the remote radio head. As VDrop is a function of the current IRRH that is supplied to the remote radio head (see Equation 2 above), if VPS (the voltage output by the power supply) is constant, then the voltage VRRH that is delivered to the remote radio head will change with the variation in current drawn by the remote radio head. Conventionally, the voltage output by the power supply (VPS) is set to ensure that the nominal supply voltage is supplied to the remote radio head (or at least a value above the minimum supply voltage) when the remote radio head draws the maximum anticipated amount of current.
The power that is lost (PLoss) in delivering the power supply signal to the remote radio head over a power cable may be calculated as follows:
P
Loss
=V
Drop
*I
RRH=(IRRH*RCable)*IRRH=IRRH2* RCable (3)
Thus, the higher the current flowing through the power cable to the remote radio head the higher the power loss.
As noted above, when conventional trunk cables are used as in the conventional cellular base station 10′ of
As noted above, pursuant to embodiments of the present invention, trunk cable assemblies having factory-sealed cable terminations 142-1, 142-2 may be used in place of combination of a trunk cable 40 and breakout boxes 42-1, 42-2 that are used in conventional approaches, since there is no need to connect power or data jumper cables within breakout boxes. When such a sealed cable terminations 142-1, 142-2 are used, each cable termination 142-1, 142-2 may further include a buck power converter or a boost power converter. In particular, cable termination 142-1 may include a boost power converter that may increase the DC voltage that is wirelessly provided from the power supply 126 to cable termination 142-1 to a much higher DC voltage (e.g., a 50 Volt DC power supply signal may be provided by the power supply may be increased to, for example, 300 Volts). This 300 Volt DC power supply signal may then be carried up the tower 130 through the power cable 210 of trunk cable 140. The cable termination 142-2 may include a buck converter that decreases the DC voltage from, for example, 295 Volts (here we are assuming a voltage drop of 5 Volts) to 50 Volts, or some other voltage that is appropriate for provision to the remote radio heads 124. Since the voltage VRRH of the power supply signal that is carried by power cable 210 is much higher than normal, the current IRRH on the power cable 210 is reduced linearly, and the power loss PLoss is reduced exponentially. This may reduce the cost of powering the remote radio heads 124 and thereby reduce the operating costs of the cellular base station 100. As a typical remote radio head 124 may require about a kilowatt of power and is run twenty-four hours a day, seven days a week, the operational cost savings may be significant.
In some cellular installations, data may be transmitted to the antennas, the data being used to control the antennas or to collect sensor data from the antennas. The Antenna Interface Standards Group (“AISG”) is a non-profit consortium that has developed a standard for digital remote control and monitoring of antennas and related equipment used in the wireless industry. Pursuant to the AISG standard, an RS-485 multi-device wired communication bus is provided that may carry control signals used to control, for example, tower-mounted power amplifiers and low noise amplifiers, antenna tilt control devices, other antenna control units and the like. The devices that receive AISG signals are referred to herein as “antenna line devices.” The communication bus may be configured, for example, in a daisy chain configuration or a star configuration in order to connect, for example, multiple antenna line devices on a tower to ground-based controller. The communication bus connects directly to each of the antenna line devices.
The AISG control signals may include, for example, location information that is provided by Global Positioning Satellite transceivers that are included in the antenna line devices (which may allow a wireless carrier to confirm that the antenna line devices were installed in the correct location), alarm signals (e.g., if a tilt angle of an antenna exceeds a predefined threshold), control signals for antenna movement or beamsteering, etc. The antenna line device controller may initiate all communications with the antenna line devices.
Pursuant to further embodiments of the present invention, the RS-485 communication bus AISG signals may be converted to an appropriate wireless signal, transmitted to the antenna line devices, and then converted back into an RS-485 signal. In some embodiments, the RS-485 cable may be incorporated into the aforementioned trunk cable assemblies. One or more additional wireless transceivers may then be included in one or both trunk cable terminations that convert the RS-485 bus signals into a wireless signal, and transmit the wireless signal to the one or more antenna line devices. The antenna line devices may convert the received wireless signal back into an RS-485 bus signal that is used to control the antenna line devices. Wireless power jumpers may also be included in each of the antenna line devices that provide the power necessary to power the AISG bus and the active circuitry in the antenna line devices (e.g., processors, tilt motors, etc.). Any of the wireless power techniques previously described may be used, and hence further description of the wireless power jumpers used to power the antenna line devices will be omitted here.
AISG signals are relatively low data rate communications. Accordingly, a number of different low data rate wireless solutions may be used to implement the wireless data jumpers from the trunk cable termination to the antenna line devices such as, for example, Bluetooth or Zigbee communications. Bluetooth and Zigbee are both low power consumption, low cost wireless networking protocols that may be incorporated into the antenna line devices and the trunk cable terminations. Moreover, since some low cost, low data rate protocols such as, for example, Zigbee have fairly extended ranges (e.g., up to 75 meters), in some embodiments, the wireless AISG communications may be transmitted from the bottom of the tower to the antenna line devices, thereby avoiding any need to incorporate the RS-485 cable into the trunk cable (or to run a separate RS-485 cable up the tower).
While embodiments of the present invention have primarily been described above with reference to conventional remote radio heads, it will be appreciated that a new generation of remote radio heads is under development that combine the remote radio head and the base station antenna into a single unit that receives digital data and outputs a radiated RF signal. Remote radio heads having this new configuration are sometimes referred to as “active antennas.” Active antennas may place the transceiver very close to the radiating elements of the antenna structure and eliminate the need for a traditional cabling connection between the remote radio head and the antenna, which may reduce signal loss (since the signal transmitted by the remote radio head is at cellular RF frequencies, and signal losses are high when transmitting such signals over coaxial cable). In active antenna arrangements, the high power amplifier may be incorporated into the radiating elements, so low power RF signals may pass between the transceiver and the amplifier/radiating elements on, for example, a short path on a printed circuit board. Signal losses may be significantly lower due to the elimination of cabling connectors, the reduction in the length of the RF signal path and the transmission of a lower power RF signal. Thus, it will be appreciated that all of the embodiments disclosed herein may be implemented using either or both conventional remote radio heads and/or active antennas as the cellular radios.
Likewise, embodiments of the present invention have primarily been described above with respect to conventional cellular base stations that have antennas mounted on an antenna tower. It will be appreciated, however, that all of the above described embodiments may be implemented in cellular base stations in which the cellular radios (i.e., conventional remote radio heads and/or active antennas) are mounted on other tower structures such as on the sides or tops of buildings, water towers, utility poles and the like, or inside structures such as stadiums, shopping malls, tunnels and the like.
The techniques according to embodiments of the present invention may offer a number of advantages. For example, the wireless data connections may reduce or eliminate the need for cleaning fiber optic connectors, stocking, ordering and distributing jumpers of particular lengths, testing fiber optic links, and the like. The installation of the equipment at the top of the tower may be simplified significantly, and may be made much safer and less expensive. The use of factory-sealed trunk cable assemblies may allow the use of higher voltage power supply signals, which may reduce power losses. Additionally, with the use of wireless power transmission techniques it is likely that remote radio heads will be developed that are powered by AC power supply signals. As AC power supply signals may generally be transmitted more efficiently than DC power supply signals, this may further reduce power losses.
Additionally, as discussed above, in some embodiments the wireless power and/or data transmission may be performed from the equipment enclosure at the bottom of the tower. In such embodiments, the need for a trunk cable can be eliminated entirely. Trunk cables are expensive to purchase, expensive to install, and create significant loads on the tower that require more robust tower structures. As such, the use of trunk cables can significantly increase the expense of a cellular base station. Additionally, because trunk cables include a large amount of copper cabling (for the power conductors), they are subject to theft. Theft of a trunk cable not only requires replacement of the trunk cable, but also shuts down operation of the cellular base station and may result in associated damage to equipment at the site.
Some embodiments of the inventive concept may provide antenna line devices (ALDs) that are Internet Protocol (IP) addressable and can, therefore, be communicated with by any entity that has access to the Internet. The ALDs are embedded systems that can be viewed as entities in the Internet of Things (IoT). As such, the ALDs may communicate and share information with each other over the Internet. In some embodiments of the inventive concept, the ALDs may include or be coupled to a wireless modem thereby allowing communication cables and circuitry (e.g., bias tees), such as those used to support the Antenna Interface Standards Group (AISG) communication protocol interface to be eliminated. AISG controller components, which are typically incorporated into the radio frequency processing equipment portion of base stations, may also be eliminated. Because the ALDs may be accessed using a wireless communication protocol, they can be placed in more convenient locations on antenna structures saving valuable real estate for other connectors and circuitry. The ALDs may also be used to store and collect information associated with a cellular base station and antenna installation. For example, one or more ALDs may collect information on transmission patterns for one or more antennas based on various elevation angles and azimuth angles for each antenna. The ALDs may also collect geographic location information for the antennas that they are associated with. An ALD management system may request and receive the antenna transmission pattern information along with the geographic location information for the antennas to generate a signal coverage map. Such a map may be useful to a service provider in determining how to configure their antennas. In other embodiments, the ALDs may store device identification information along with identification information for the antennas that they are associated with. Frequency scanning module ALDs may be used to determine the frequency spectrum that is in use at an antenna. The ALD management system may request and receive the ALD device identification information, the antenna identification information, and the frequency spectrum usage information for the antenna(s), which can be processed to generate a summary or inventory of the equipment in use at a base station installation site along with what portion of the frequency spectrum is in use. Such an installation site summary may be generated for one or more service providers, which may be helpful in determining when to schedule maintenance of equipment, replacement of equipment, and in engineering the cellular network.
ALDs are described herein as being coupled to an antenna or other type of structure, for example. It will be understood that when an ALD is described as being coupled to another element, for example, the ALD may be a separate distinct unit from the other element or the ALD may be incorporated on or within the other element so as to be a part of the other element.
The support structure for the antennas 1335 may include one or more ALDs 1315a, 1315b, 1315c, and 1315d. In the example of
The core network 1310, access network 1312, and access network 1313 may be a global network, such as the Internet or other publicly accessible network. Various elements of the core network 1310, access network 1312, and access network 1313 may be interconnected by a wide area network, a local area network, an Intranet, and/or other private network, which may not be accessible by the general public. Thus, the core network 1310, access network 1312, and access network 1313 may represent a combination of public and private networks or a VPN. The core network 1310, access network 1312, and access network 1313 may be a wireless network, a wireline network, or may be a combination of both wireless and wireline networks.
Although
For example, when the ALD 1400 is a tower mounted amplifier 1315a, the ALD function 1415 may be configured to adjust an amplification of a signal received from the output of an antenna responsive to a control signal, such as a message, signal, or the like, from the ALD management system 1345. When the ALD 1400 is a remote electrical tilt system 1315b, the ALD function 1415 may be configured to adjust one or more of an elevation angle of the antenna and an azimuth angle of the antenna responsive to a control signal from the ALD management system 1345. When the ALD 1400 is an antenna sensor device 1315c, the ALD function 1415 may be configured to collect information that is associated with the antenna, such as, but not limited to, azimuth angle, elevation angle, latitude coordinate, longitude coordinate, Global Positioning System (GPS) coordinates, wind speed, temperature, vibration amplitude, and vibration frequency. This information may be stored as data 1425 in the memory 1420. When the ALD 1400 is a frequency scanning module 1315d, the ALD function 1415 may be configured to determine the frequency spectrum in use at the antenna. ALDs, such as remote electrical tilt systems and antenna sensor devices may be configured to collect information, such as transmission patterns of an antenna based on elevation angles, respectively, which can be stored as data 1425. ALDs such as remote electrical tilt systems and antenna sensor devices may be configured to collect information, such as gain of an antenna, return loss of an antenna, and isolation of an antenna, which can be stored as data 1425. Each of the various types of ALDs may be configured to store identification information indicating one or more of the ALD type, manufacturer, date of installation, installation location, and the like. The ALDs may also store similar information for the one or more antennas that they are associated with.
As shown in
Referring now to
As shown in
The ALD control module 1620 may comprise a user interface module 1625, a device command module 1627, a coverage map module 1630, an inventory module 1635, and a site configuration module 1640. The user interface module 1625 may be configured to provide an interface to receive user input for sending control signals, messages, and the like to one or more ALDs and also for displaying information collected from ALDs.
The device command module 1627 may be configured to generate commands through use of control signals, messages, and the like to one or more ALDs to control their operation. These commands may be used to drive the ALDs to perform particular operations and/or to collect data from the ALDs that the ALDs have stored in local memory.
As described above, an ALD, such as a remote electrical tilt system, may be used to store transmission patterns based on the elevation angle and/or azimuth angle of an antenna. Moreover, various types of ALD devices that are associated with an antenna can provide geographic location coordinates for the antenna, such as GPS coordinates and/or latitude and longitude coordinates. The coverage map module 1630 may be configured to collect the antenna transmission patterns for one or more antennas from one or more ALDs along with the geographic location or each antenna and use this information to generate a cellular service signal coverage map, which can be provided to a user through the user interface module 1625. Moreover, in some embodiments, the coverage map may show service boundaries for antennas associated with a single and/or multiple service providers.
As described above, the various types of ALDs may store identification information indicating one or more of the ALD type, manufacturer, date of installation, installation location, and the like. An ALD may also store similar information for the one or more antennas that is it associated with. The inventory module 1635 may be configured to collect the inventory information from various ALDs, which may be helpful to a service provider in tracking what equipment is installed, how old the equipment is, who the manufacturer is, and other useful information that can be derived from the identification information.
The site configuration module 1640 may be configured to process the inventory information collected by the inventory module 1635 to generate an installation site summary that shows what equipment is installed and is in service at a site comprising a base station and one or more antennas. In addition to the inventory information, the site configuration module 1640 may incorporate frequency spectrum usage collected from frequency scanning module ALDs 1315d associated with the particular antennas at an installation site. The installation site summary may be presented to a user via the user interface 1625 in a textual format or, in other embodiments, in a graphical format with icons showing the various equipment with textual annotations providing more detail about each equipment icon. The site configuration module 1640 may generate installation site summaries for sites associated with a single or multiple service providers.
Although
Computer program code for carrying out operations of data processing systems discussed above with respect to
Moreover, the functionality of the ALD management system 1345 and ALDs 1315a, 1315b, 1315c, and 1315d of
The data processing apparatus of
Some embodiments of the inventive concept may provide ALDs that are IP addressable and, therefore, can be communicated with as entities in the IoT. The ALDs may be configured to communicate via wireless communication protocol, which may eliminate the need for the wiring and support circuitry used to support conventional AISG communication. The ALDs may also be used to collect and store various types of information associated with a cellular base station installation including, but not limited to, antenna transmission patterns, antenna sensor data, frequency use information, component identification information, and the like, which may be accessed over the Internet and processed to allow service providers to better manage their networks.
In the above-description of various embodiments of the present disclosure, aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or contexts including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Accordingly, aspects of the present disclosure may be implemented entirely hardware, entirely software (including firmware, resident software, micro-code, etc.) or combining software and hardware implementation that may all generally be referred to herein as a “circuit,” “module,” “component,” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product comprising one or more computer readable media having computer readable program code embodied thereon.
Any combination of one or more computer readable media may be used. The computer readable media may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an appropriate optical fiber with a repeater, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable instruction execution apparatus, create a mechanism for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable medium that when executed can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions when stored in the computer readable medium produce an article of manufacture including instructions which when executed, cause a computer to implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer, other programmable instruction execution apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatuses or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various aspects of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The present invention has been described with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments that are pictured and described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the specification and drawings. It will also be appreciated that the embodiments disclosed above can be combined in any way and/or combination to provide many additional embodiments.
It will be understood that, although the terms first, second, etc. are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Unless otherwise defined, all technical and scientific terms that are used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the above description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this disclosure, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when an element (e.g., a device, circuit, etc.) is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
In the drawings and specification, there have been disclosed typical embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.
The present application claims priority under 35 U.S.C. § 120 as a continuation in part of U.S. patent application Ser. No. 15/271,570, filed Sep. 21, 2016, which is a continuation of U.S. patent application Ser. No. 14/708,386, filed May 11, 2015, which in turn claims priority under 35 U.S.C. § 119 to U.S. Provisional Application Ser. No. 61/991,689, filed May 12, 2014. The present application further claims priority under 35 U.S.C. § 120 and 35 U.S.C. § 365(c) to International Application No. PCT/US2017/062492 filed Nov. 20, 2017, which claims priority to U.S. Provisional Application Ser. No. 62/428,920, filed Dec. 1, 2016. The entire content of each of the aforementioned applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61991689 | May 2014 | US | |
| 62428920 | Dec 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14708386 | May 2015 | US |
| Child | 15271570 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15271570 | Sep 2016 | US |
| Child | 15865714 | US | |
| Parent | PCT/US2017/062492 | Nov 2017 | US |
| Child | 14708386 | US |
