WO2016077529A1

WO2016077529A1 - Method for aligning base station antennae at a cell site

Info

Publication number: WO2016077529A1
Application number: PCT/US2015/060291
Authority: WO
Inventors: Kevin Eldon Linehan; Morgan C. KURK
Original assignee: Commscope Technologies Llc
Priority date: 2014-11-12
Filing date: 2015-11-12
Publication date: 2016-05-19

Abstract

Methods for aligning base station antennae at a cell site, the base station antenna which may include a first antenna, a second antenna, and a third antenna, each providing coverage of a respective sector of the cell site, may involve taking measurements of signals received in regions of antennae coverage overlap and adjusting azimuth angles of one or more of the antennae to substantially equalize received signal strengths.

Description

TITLE

Method for Aligning Base Station Antennae at a Cell Site

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application No.

62/078,591 , filed on November 12, 2014, the entire contents of which are incorporated herein by reference in their entirety.

BACKGROUND

[0002] Various aspects of the present disclosure relate to base station antennae, and, more particularly, to methods for aligning base station antennae at a cell site.

[0003] Base station antennae, or sector antennae, may generally be mechanically aligned through the use of several methods including dead reckoning, using compass headings (e.g., a magnetic compass), and using global positioning system (GPS) coordinates. In each of these methods, a reference point for alignment of a base station antenna is a back radome/reflector surface, which is assumed to be orthogonal to the peak of the base station antenna's beam.

However, this assumption may not be accurate due to mechanical and material variances of the back radome/reflector structure; as well as variances in the pattern shape of the beam. Errors in correctly pointing a base station antenna may reduce the signal strength or coverage of a sector by a corresponding base station antenna, while causing excessive interference in an adjacent sector. Accordingly, there is a need for a method for accurately aligning base station antennae.

SUMMARY OF THE DISCLOSURE

Various aspects of the present disclosure may be directed to methods for aligning base station antennae at a cell site. In one aspect, a cell site may include base station antennae including a first antenna, a second antenna, and a third antenna, which may provide coverage of respective sectors of the cell site. While a first antenna is pointed in a direction at an initial azimuth angle, a first radio frequency (RF) signal strength of at least one signal transmitted by the first antenna may be measured at a second antenna; and a second RF signal strength of the at least one signal may be measured at a third antenna. It may then be determined whether the first and second RF signal strengths are equal. In response to determining that the first and second RF signal strengths are unequal, the azimuth angle of the first antenna may be adjusted. This process may be repeated until the first and second RF signal strengths are equal. The second and third antennae may be aligned in a similar fashion.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0004] The following detailed description of the invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0005] In the drawings:

[0006] Fig. 1 is a plan view of a cell site having base station antennae with respective theoretical antenna beams;

[0007] Fig. 2 is a plan view of an actual antenna beam pattern of one base station antenna;

[0008] Fig. 3 is a plan view of a cell site having base station antennae having respective antenna beams with equalized inter-sector interference, according to an aspect of the present disclosure;

[0009] Fig. 4 is a method of aligning base station antennae of a cell site according to an aspect of the present disclosure; and

[0010] Fig. 5 is a plan view of a cell site having base station antennae having respective antenna beams with equalized inter-sector interference, according to an aspect of the present disclosure. DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0011] Certain terminology is used in the following description for convenience only and is not limiting. The words "lower," "bottom," "upper" and "top" designate directions in the drawings to which reference is made. Unless specifically set forth herein, the terms "a," "an" and "the" are not limited to one element, but instead should be read as meaning "at least one." The terminology includes the words noted above, derivatives thereof and words of similar import. It should also be understood that the terms "about," "approximately," "generally," "substantially" and like terms, used herein when referring to a dimension or characteristic of a component of the invention, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally similar. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.

[0012] As discussed above, the reference point for alignment of each of the base station antennae are assumed to be orthogonal to the peak of the antenna beam. Figure 1 is a plan view of a cell site considering this assumption. The cell site 10 may comprise a triangular platform 12, which may be mounted atop an antenna tower (not shown), or other suitable structure, such as a building (not shown). The platform may include a first side, a second side, and a third side, each of which may have one or more base station antennae 11, 13, and 15, having respective base station antenna beams 17, 19, and 21 shown serving three sectors, each having a range of 120 degrees, respectively. As shown, the pattern shape of each theoretical antenna beam 17, 1 , and 21 may be symmetrical. Even though only three sectors and three base station antennae are illustrated, it is understood that a cell site may contain any number of sectors and any number of base station antennae, each having an antenna beam covering any degree range.

[0013] In an actual, real-life environment, antenna beams may exhibit little symmetry. An example of one such actual antenna beam 22 of a base station antenna is shown in Figure 2. Consequently, antenna pointing errors often occur, resulting in reduced RF signal strength or coverage of a sector by a corresponding base station antenna, while causing excessive interference in an adjacent sector (e.g.. by a beam of an antenna covering the adjacent sector), otherwise known as inter-sector interference. To minimize the aforementioned errors, one may employ techniques that seek to minimize the negative impact of the asymmetrical nature of antenna beams by equalizing the RF signal strength at sector boundaries for a cell site by RF measurement with simultaneous antenna pointing adjustment.

[0014] Referring now to Figure 3, for each of the base station antennae 1 1, 13, and 15, an RF signal strength of at least one signal (e.g., at least one pilot signal having a unique identifier) may be measured at edges of a sector that the base station antenna is covering with respective actual (i.e., in a real-world environment) antenna beams 23, 25, and 27. To accomplish this, base station antenna 11 may be configured, such as by the operator via the base station (not shown), to transmit at least one pilot signal. The other base station antennae 13 and 15 covering sectors adjacent to the sector covered by base station antenna 1 1 may be configured to receive the one or more pilot signals. The RF signal strengths of the signals may then be measured at each of the adjacent base station antennae, 13 and 15. RF signal strengths, as discussed herein, may be measured at each of the base station antennas 11, 13, and 15, using various devices which may include but are not limited to: a base station analyzer, a spectrum analyzer, a computing device, and the like. Based on the RF signal strength measurements, the horizontal beam pointing direction (referred to herein as azimuth angle) may be physically adjusted. Stated differently, the base station antenna 1 1 may be horizontally steered towards or away from either one of the adjacent base station antennae 13, 15, effectively altering the coverage of the antenna beam 23 of the base station antenna 11, which, may in turn, alter the level of interference seen at the respective sector edges. Accordingly, the base station antenna 1 1 may be horizontally steered until the RF signal strength measured at the other base station antennae 13 and 15 in their respective sectors is substantially equal.

[0015] The same process may be repeated for the remaining base station antennae 13, 15 at the cell site. For example, the base station antenna 13 may now be configured to transmit at least one pilot signal, while the other base station antennae 1 1 and 15 may be configured to receive the at least one pilot signal. The RF signal strength of the transmitted pilot signal(s) may be measured at base station antennae 11 and 15. Similarly to above with respect to the base station antenna 11. the base station antenna 13 may be periodically steered (and the RF signal strengths may be simultaneously measured) at the other base station antennae 1 1 and 15, until the measured RF signal strengths of the transmitted pilot signals are substantially equal. Even though only three sectors and three base station antennae are illustrated, it is understood that embodiments of the present invention may be employed at a cell site containing any number of sectors and any number of base station antennae, each having an antenna beam covering any degree range.

[0016] Upon repeating this process for the remaining base station antenna 15, each of the antennae 1 1 , 13, and 15 may be accurately aligned in its respective azimuth angle. With the base station antennae now more accurately aligned, the area of antennae beam overlap at each of the sector boundaries 31, 33, and 35 may be substantially equal, as shown in Fig. 3.

[0017] FIG. 4 is a flow chart illustrating a method 400 for aligning a base station antenna (e.g., a first antenna) at a cell site having a first antenna, a second antenna, and a third antenna. While the first antenna is pointed in a direction at an initial azimuth angle, a first RF signal strength of at least one signal transmitted from a first antenna may be measured at a second antenna (Block 401); and a second RF signal strength of the at least one signal transmitted from the first antenna may be measured at a third antenna (Block 403). It may then be determined whether the first and second RF signal strengths are substantially equal (Block 405). If it is determined that the first and second RF signal strengths are unequal, the azimuth angle of the first antenna may be adjusted (Block 407).

[0018] In another technique, a method may use a global positioning system (GPS) enabled device to measure signal strengths of signals at sector edges. Base station antennae may be horizontally adjusted until sector edge signal strengths are substantially equalized. The term "GPS enabled device" may refer to a smart phone, a tablet, an e-reader, a mobile gaming console, a personal computer, an mp3 player, an i Pod or any other device that is GPS enabled and capable of RF signal strength measurement. Similar to Fig. 3, Fig. 5 illustrates a cell site 10 shown having a triangular platform 12, which may be mounted atop an antenna tower (not shown), or other suitable structure, such as a building (not shown). The platform as shown includes a first side, a second side, and a third side, each of which have one or more base station antennae 1 1 , 13. and 15, shown having respective antenna beams 23, 25, and 27 serving three sectors, each having a range of 120 degrees, respectively. Also shown in Fig. 5 is a GPS enabled device 37. With the GPS enabled device 37 located preferably at a sector boundary (such as, for example 31), two antennas 11 and 13 having adjacent beams 23 and 25, respectively, may be configured to transmit respective known signals (such as continuous wave signals). Because these signals are predetermined known (e.g., continuous \vave signals), the GPS enabled device may be able to identify (e.g., through an identifier unique to each signal) from which antenna each signal is transmitted. The GPS enabled device may measure RF signal strengths of the respective continuous wave signals. The antennae may be steered horizontally until the RF signal strengths of the signals (measured at the GPS enabled device) are substantially equal.

This same process may be repeated for all adjacent pairs of antennae (e.g., 13 and 15) at the cell site 10. Even though only three sectors and three base station antennae are illustrated, it is understood that embodiments of the present invention may be employed at a cell site containing any number of sectors and any number of base station antennae, each having an antenna beam covering any degree range.

[0019] Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0020] Those of skill would further appreciate that the various illustrative blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0021] The various illustrative blocks described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0022] Various embodiments of the invention have now been discussed in detail; however, the invention should not be understood as being limited to these embodiments. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention.

Claims

CLAIMS What is claimed is:

1. A method of aligning base station antennae at a cell site, the base station antennae including a first antenna, a second antenna, and a third antenna, each providing coverage of a respective sector of the cell site, the method comprising:

while the first antenna is pointed in a direction of a first azimuth angle:

measuring, at the second antenna, a first radio frequency (RF) signal strength of at least one first signal transmitted from the first antenna;

measuring, at the third antenna, a second RF signal strength of the at least one first signal transmitted from the first antenna; and

determining whether the first and second RF signal strengths are substantially equal; in response to determining that the first and second RF signal strengths are unequal, adjusting the first azimuth angle of the first antenna.

The method of claim 1, further comprising:

while the first antenna is pointed in a direction of the adjusted first azimuth angle:

measuring, at the second antenna, a third RF signal strength of at least one second signal transmitted from the first antenna;

measuring, at the third antenna, a fourth RF signal strength of at the least one second signal transmitted from the first antenna; and

determining whether the third and fourth RF signal strengths are substantially equal.

The method of claim 2, further comprising:

while the second antenna is pointed in a direction of a second azimuth angle:

measuring, at the first antenna, a fi th RF signal strength of at least one third signal transmitted from the first antenna;

measuring, at the third antenna, a sixth RF signal strength of the at least one third signal transmitted from the first antenna; and

determining whether the fifth and sixth RF signal strengths are substantially equal.

4. The method of claim 3, further comprising:

while the second antenna is pointed in a direction of an adjusted second azimuth angle:

measuring, at the first antenna, a seventh RF signal strength of at least one fourth signal transmitted from the second antenna;

measuring, at the third antenna, an eighth adjusted RF signal strength of the at least one fourth signal transmitted from the second antenna; in response to determining that the seventh and eighth RF signal strengths are unequal, adjusting the second azimuth angle of the second antenna.

5. The method of claim 1. wherein the cell site comprises a fourth antenna configured to provide coverage of a sector of the cell site.

6. The method of claim 1, wherein the at least one signal comprises a pilot signal having a unique identifier.

7. A method of aligning base station antennae at a cell site, the base station antennae including a first antenna, a second antenna, and a third antenna, each providing coverage of a respective sector of the cell site, the method comprising:

while the first and second antennas are pointed in respective directions at respective initial azimuth angles:

measuring, by a signal strength measurement device positioned at a boundary of the respective sectors covered by the first and second antennas, a first radio frequency (RF) signal strength of at least one first predetermined signal transmitted from the first antemia;

measuring, by the signal strength measurement device, a second RF signal strength of at least one second predetermined signal transmitted from the second antenna; and

determining whether the first and second RF signal strengths are substantially equal; in response to determining that the first and second RF signal strengths are unequal, adjusting the azimuth angle of the first antenna.

8. The method of claim 7, further comprising: while the first antenna is pointed in the adjusted first direction:

measuring, by the signal strength measurement device, a third RF sig strength of at least one third predetermined signal transmitted from the first antenna; and

determining whether the third RF signal strength and the second RF strength are substantially equal.

9. The method of claim 8, further comprising:

in response to determining that the third RF signal strength and the second RF signal strength are substantially equal, positioning the signal strength measurement device, at a boundary of the respective sectors covered by the second and third antennas;

while the second and third antennas are pointed in respective directions at respective initial azimuth angles:

measuring, by the signal strength measurement device positioned at a boundary of the respective sectors covered by the second and third antennas, a fourth RF signal strength of at least one fourth predetermined signal transmitted from the second antenna;

measuring, by the signal strength measurement device, a fifth RF signal strength of at least one fifth predetermined signal transmitted from the second antenna; and

determining whether the fourth and fifth RF signal strengths are substantially equal; and

in response to determining that the fourth and fifth RF signal strengths are unequal, adjusting the azimuth angle of the second antenna.

The method of claim 9, further comprising:

while the second antenna is pointed in the adjusted second direction:

measuring, by the signal strength measurement device, a sixth RF signal strength of at least one sixth predetermined signal transmitted from the second antenna; and

determining whether the fifth RF signal strength is substantially equal to the sixth RF signal strength.

11. The method of claim 7, wherein the signal strength measurement device is a global positioning system (GPS) enabled device.

12. The method of claim 7, wherein the cell site further comprises a fourth antenna configured to provide coverage of a sector of the cell site.