The present invention relates generally to wireless repeaters, which are also known as cellular signal enhancers. More particularly, the invention relates to a wireless repeater that includes a universal server base unit and modular donor antenna options that allows the user to select among a variety of donor antennas including internal donor antenna options mounted within the universal server base unit and external donor antenna options connected to the universal server base unit by a coaxial cable.
Wireless repeaters, which are also referred to as cellular signal enhancers, serve an important function in the cellular telephone industry. They can be implemented as portable “personal repeater” units that receive, amplify and repeat bidirectional wireless telephone signals between cellular base stations and wireless telephones located in a structure, typically a home or office, where low signal strength from the base station causes degraded service or, in some cases, no service at all. In addition, low signal strength causes the wireless telephone to increase its transmission power, which drains the battery more quickly. This makes the wireless repeater an important, if not indispensable, piece of equipment for a wide range of customers, including the increasing number of customers who rely on wireless telephone service exclusively and, therefore, do not have a land line alternative available in their homes or businesses. Sufficiently reliable wireless telephone service is also especially important for those who rely on wireless telephone service for data communications, such as Internet access, credit card transactions, intranet communications with a remote office location, and the like.
Because a portable wireless repeater is designed to be installed in homes and businesses (for this reason the personal repeater is sometimes referred to as “customer premises equipment” or CPE), it is also desirable for the units to be as inconspicuous and aesthetically pleasing as possible. One approach described in U.S. Ser. Nos. 10/375,879; 11/127,668 and 11/372,856 locates the server and donor antennas within a single enclosure, which also reduces the cost and weight in most instances and generally eases installation. Making the unit wireless repeater small and deployed in a single housing, however, brings the server and donor antennas into close proximity. This generally increases the tendency of the repeater to develop positive feedback instability, thereby limiting the gain that can be effectively applied by the unit. Innovations that help to alleviate positive feedback instability by improving server-donor antenna feedback suppression are therefore desirable to permit reduced size of the unit, increased gain, and improved signal quality. Accordingly, there is an ongoing need for techniques that improve the server-donor antenna feedback suppression in a wireless repeater. This capability should be implemented in a cost effective, reliable, flexible and sturdy manner to the extent possible.
In addition, flexibility is also desirable for products intended to be installed in a wide range of customer premises having different installation concerns and signal strength considerations. On one hand, standardization is desirable to minimize the part count required to support a product line, and on the other hand, flexibility is desirable to allow users to select among available options to meet their individual needs and preferences. This is a particularly relevant tradeoff when designing a product line intended for wide spread installation in homes and businesses, where customer preference, installation requirement and signal strength conditions are expected to vary widely. Accordingly, there is an ongoing need for cost effective wireless repeater configurations that provide customers with desirable choices.
The present invention meets the needs described above in a wireless repeater that includes a universal server base unit that accepts a variety of modular donor antenna options including an internal donor antenna board and an internal adapter module that typically includes a cable port for receiving a coaxial cable connected to an external donor antenna option. This allows the same universal server base unit to work with a variety of internal and external donor antenna options. The server base unit preferably includes a dual polarization server antenna using different polarizations for the uplink and downlink signal paths and a diplexer that enables duplex communication of the downlink and uplink signal paths over a single coaxial cable to an external donor antenna. The external donor antenna options include outdoor swivel-mounted options including a helical circular polarization antenna, a dual polarization panel antenna, and a vertical polarization panel antenna. The external dual polarization antenna option uses different polarizations for the uplink and downlink signal paths and also includes a diplexer to enable duplex communications with the server base unit over the single coaxial cable connection. The external donor antenna options may also include an optional donor bidirectional amplifier that is powered via the cable from the server base unit.
Generally described, the invention may be implemented as a wireless repeater that includes a server base unit having a dual polarization server antenna having a downlink portion and an uplink portion located within a portable housing. The repeater also includes a dual polarization donor antenna located outside the housing having a downlink portion and an uplink portion and a communication link operatively connecting the donor antenna and the server base unit. The server base unit also includes a bidirectional amplifier, mounted within the housing, connecting the donor and server downlink portions in a downlink signal path, and also connecting the donor and server uplink portions in an uplink signal path. A base unit diplexer located at the base unit and a donor diplexer located at the donor antenna enable duplex communication of the downlink and uplink signal paths over the communication link. It should be appreciated that this embodiment implements dual cross-polarization isolation, in which wherein the donor downlink and uplink portions have different polarization states, the server downlink and uplink portions have different polarization states, the donor and server downlink portions have different polarization states, and the donor and server uplink portions have different polarization states. In other words, the wireless repeater implements cross polarization both along and between the uplink and downlink signal paths to help avoid positive server-donor feedback oscillations.
In an alternative configuration, the wireless repeater includes a circular polarization donor antenna located outside the housing and a communication link operatively connecting the donor antenna and the server base unit. In another alternative configuration, the circular polarization antenna is replaced by a linear single polarization donor antenna, which may be, for example, a vertical, horizontal or 45 degree slant polarization antenna. For any of these embodiments, the server may be a two-element array of dual polarization microstrip patch antenna elements in which the downlink circuit includes balanced, horizontal polarization antenna feeds and the uplink circuit includes quasi-balanced, vertical polarization antenna feeds. In addition, the wireless repeater may include a pedestal for pivotally mounting the server base unit in a first location of a structure and a swivel mount for mounting the donor antenna in a second location of the structure, to allow the server base unit and the donor antenna to be separately pointed in desired directions.
The specific techniques and structures for implementing this invention will become apparent from the following detailed description of the embodiments and the appended drawings and claims.
The present invention may be implemented as an improvement to the wireless repeater described in commonly-owned copending U.S. patent application Ser. No. 11/372,856 entitled “Dual Polarization Wireless Repeater Including Antenna Elements with Balanced and Quasi-Balanced Feeds” filed Mar. 11, 2006, which describes a number of improvements over a “first generation” wireless repeater described in commonly-owned copending U.S. patent application Ser. No. 10/375,879 entitled “Cellular Signal Enhancer” filed Feb. 26, 2003. The server base unit described in the present application may be basically the same as any of the wireless repeater units described in these prior applications, except that they have been modified to accept a variety of donor antenna options including internal donor antenna options and external donor antenna options connected to the base unit by a communication link, such as a coaxial cable. Therefore, it should be understood that any of the features described in the prior applications can be implemented in the embodiments of the present invention including, for example, frequency band selection, remotely reconfigurable parameters and controllable settings, mechanical antenna isolation techniques, balance and quasi-balanced antenna feeds, dual cross-polarization isolation, and the handy base unit mounting pedestals described in U.S. patent application Ser. No. 11/127,668.
For any of these configurations, an improvement of the present invention lies in a universal server base unit that accepts a variety of modular donor antenna options. Accordingly, the universal server base unit includes a base unit bidirectional amplifier, a server antenna, and a housing that accepts an internal donor antenna board or an internal adapter module that includes a communication interface, such as a cable port for receiving a coaxial cable connected to an external donor antenna. This allows the same universal server base unit to work with a variety of internal and external donor antenna options. In particular, the external donor antennas include outdoor swivel-mounted options including a helical circular polarization antenna, a dual polarization panel antenna, and a linear, single polarization panel antenna such as a vertical, horizontal or 45 degree slant polarization antenna. The donor antenna may also include an optional donor bidirectional amplifier that is powered via the cable from the server base unit.
In one embodiment, the donor antenna is a dual polarization antenna using different polarizations for the uplink and downlink signal paths. In this case, the donor antenna includes a diplexer enabling the uplink and downlink communication to be carried on a single coaxial cable. This embodiment thus implements dual cross-polarization isolation including cross polarization both along and between the uplink and downlink signal paths using an external donor antenna and a single cable connecting the donor antenna to the server base unit. However, it should be appreciated that many different types of donor antenna options can be used with the universal server base unit, and the particular options described below are merely illustrative of the options available.
Turning now to the drawings, in which like numerals refer to like elements throughout the several figures,
In the universal server base unit 12, the preferred server antenna 22 is a dual-polarization antenna that includes a downlink portion 24 having a first polarization and an uplink portion 26 having a second polarization that is different than the first polarization. In the particular embodiment shown in
In addition to the server antenna 22, the universal server base unit 12 also includes a bidirectional amplifier (BDA) 30 that transmits and amplifies the communication signals between the server and donor antennas. This BDA implements the wide range of remotely controllable and reconfigurable functionality as described in U.S. Ser. No. 11/372,856. The base unit also includes a donor antenna board that can be swapped out for an adapter module that includes a communication link, preferably a coaxial cable receptacle, for connecting an external donor antenna to the universal server base unit 12. Because the server antenna is a dual polarization antenna that uses different polarizations for the uplink and downlink signal paths, the adapter module 31 includes a diplexer that allows a single coaxial cable 16 to carry both the uplink and the downlink communication signals between the server base unit 12 and the external donor antenna 14a.
More specifically, the BDA includes a downlink amplifier circuit 34 that receives communication signals from the donor antenna via the cable 16 and the adapter module 31, amplifies theses signals and delivers them to the downlink portion 24 of the server antenna. Similarly, the BDA 12 includes an uplink amplifier circuit 36 that receives communication signals from the uplink portion 26 of the server antenna, amplifies theses signals and delivers them to the donor antenna 14a by way of the cable 16 and the adapter module 31. Thus, the downlink signal path 38 refers to the communication path from the carrier's base station 20 to the customer's mobile unit 18, whereas the uplink signal path 40 refers to the communication path from the mobile unit to the base station. The donor antenna may also include a local donor BDA 32, which is preferably powered by the base unit 12 through the cable 16. It should be noted that the BDA 30 in the base unit 12 is preferably configured to implement an intermediate frequency (IF) used for frequency channel selection (as described in U.S. Ser. No. 11/372,856), while the local donor BDA 32 may be a more traditional RF frequency BDA (as described in U.S. Ser. No. 10/375,879). In addition, the local donor BDA 32 may be built into the same enclosure with the donor antenna, or it may be housed separately as an auxiliary component.
A distinguishing feature of the present invention is the use of a universal server base unit 12 that can accept a number of different donor antenna options. In particular, a variety of different modular donor antenna boards may be selectively installed inside the base unit to construct different versions of the back-to-back wireless repeater described in U.S. Ser. No. 11/372,856. Also, the internal donor antenna module may be replaced by the adapter module 31 shown in
In order to accept external donor antenna options, the internal donor antenna board can be removed and replaced by an adapter module 31, which includes a small microstrip diplexer unit deployed PC board and a length of coaxial cable that extends to a coaxial cable port 58 located at an edge of the universal server unit. The adapter module 31 allows a variety of different external donor antenna modules 14a-n to be connected to the universal server unit 12. Specifically, the diplexer operates as a dual bandpass filter that imparts sufficient frequency isolation between the uplink and downlink communication channels to allow both channels to be carried on a single coaxial cable 16. External donor antenna options can include but need not be limited to flat panel antenna options. For example, the available external donor antenna options can include a circular polarization helical antenna 14a, a dual polarization microstrip patch panel antenna 14b, a vertical polarization microstrip patch panel antenna 14c, or any other type of suitable donor antenna configuration. The dual polarization donor antenna module 14b preferably includes a diplexer 46 so that a single coaxial cable 16 can be used to connect the donor antenna to the universal server unit 12. Any of these options may, but need not, include a local donor BDA 32 that receives its power from the universal server unit 12 via the cable 16. Of course, the BDA 32 could be powered separately, for example by a power cord extending to power outlet.
The donor antenna 14a is also shown in
Referring to
In this particular antenna, the two horizontally oriented, opposing element feeds 106a and 106a′ form a balanced, horizontal polarization feed arrangement 107a for the upper server antenna element 104a. In addition, the single vertically-oriented, downward facing element feed 116a forms an unbalanced, vertical polarization feed arrangement for the upper server antenna element 104a. Thus, the upper server antenna element 104a is a dual-polarization antenna element that includes a combination of a balanced and unbalanced antenna feed arrangements. Specifically, the downlink portion of the antenna element 104a includes a balanced, horizontal polarization feed arrangement implemented by the horizontally oriented, opposing element feeds 106ab and 106a′. In addition, the uplink portion of the antenna element 104a includes an unbalanced, vertical polarization feed arrangement implemented by the antenna feed 116a. The same can be said for the lower server antenna element 104b. That is, the downlink portion of the lower server antenna element 104b includes a balanced, horizontal polarization feed arrangement 107b implemented by the horizontally oriented, opposing element feeds 106b and 106b′. And the uplink portion of the lower server antenna element 104b includes an unbalanced, vertical polarization feed arrangement implemented by the antenna feed 116b. In addition, the unbalanced feeds 116a and 116b form a two-element, quasi-balanced antenna feed configuration 117. Alternatively, the server antenna could include balanced feeds for both the uplink and downlink circuits. However, this dual-balanced configuration requires crossovers in the feed circuit, as described in U.S. Ser. No. 11/372,856.
For the donor uplink circuit, the donor antenna feed circuit 120 includes a diplexer 200, which connects donor uplink circuit trace 202 and a donor downlink circuit trace 212 to an RF port 210 that connects to the cable port 70 shown on
The donor downlink circuit trace 212 connects to the upper-left donor antenna element 204a at two opposing, vertically oriented element feeds 216a and 216a′ forming a balanced, vertically oriented feed arrangement 217a. Similarly, the donor downlink circuit trace 212 connects to the upper-right donor antenna element 204b at two opposing, vertically oriented element feeds 216b and 216b′ forming a balanced, vertically oriented feed arrangement 217b. The donor downlink circuit trace 212 also connects to the lower-left donor antenna element 204c at two opposing, vertically oriented element feeds 216c and 216c′ forming a balanced, vertically oriented feed arrangement 217c. Similarly, the donor downlink circuit trace 212 connects to the lower-right donor antenna element 204d at two opposing, vertically oriented element feeds 216d and 216d′ forming a balanced, vertically oriented feed arrangement 217d.
In addition, the uplink portion of the donor antenna includes a first unbalanced, horizontal polarization antenna feed arrangement implemented by the horizontally oriented antenna feed 206a for the upper left antenna element 204a. A second unbalanced, horizontal polarization antenna feed arrangement is implemented by the horizontally oriented antenna feed 206b for the upper right antenna element 204b. A third unbalanced, horizontal polarization antenna feed arrangement is implemented by the horizontally oriented antenna feed 206c for the lower left antenna element 204c. And a fourth unbalanced, horizontal polarization antenna feed arrangement is implemented by the horizontally oriented antenna feed 206d for the lower right antenna element 204d. It should also be understood that the upper antenna elements 204a and 204b form a quasi-balanced feed arrangement 207a implemented by the opposing, horizontally oriented antenna feeds 206a and 206b located on two adjacent antenna elements. Similarly, the lower antenna elements 204c and 204d form a quasi-balanced feed arrangement 207b implemented by the opposing, horizontally oriented antenna feeds 206c and 206d located on two adjacent antenna elements.
In view of the foregoing, it will be appreciated that present invention provides significant improvements in wireless repeaters. It should be understood that the foregoing relates only to the exemplary embodiments of the present invention, and that numerous changes may be made therein without departing from the spirit and scope of the invention as defined by the following claims.
This application incorporates by reference commonly-owned copending U.S. patent application Ser. No. 10/375,879 entitled “Cellular Signal Enhancer” filed Feb. 26, 2003; U.S. patent application Ser. No. 11/127,668 entitled “Mounting Pedestal for a Cellular Signal Enhancer” filed May 13, 2005; and U.S. patent application Ser. No. 11/372,856 entitled “Dual Polarization Wireless Repeater Including Antenna Elements with Balanced and Quasi-Balanced Feeds” filed Mar. 11, 2006.