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Method and apparatus for reducing gps receiver jamming during transmission in a wireless receiverMethod and apparatus for reducing gps receiver jamming during transmission in a wireless receiver description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060055594, Method and apparatus for reducing gps receiver jamming during transmission in a wireless receiver. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. .sctn.119(e) of U.S. Provisional Patent Application No. 60/224,741, filed Aug. 10, 2000, entitled "METHOD AND APPARATUS FOR REDUCING GPS RECEIVER JAMMING DURING TRANSMISSION IN A WIRELESS TRANSCEIVER," by Richard J. McConnell, et al., which application is incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates in general to wireless transceivers integrated with a Global Positioning System (GPS) receiver, and in particular to a method and apparatus for reducing GPS receiver jamming during transmission by the wireless transceiver. [0004] 2. Description of the Related Art [0005] Wireless communications systems, including cellular telephony, Personal Communication System (PCS) devices, Personal Data Assistants (PDAs), and other wireless handsets and devices, has become commonplace. The use of such devices to provide voice, data, and other services, such as internet access, has provided many conveniences to wireless system users. [0006] Currently, designers are integrating Global Positioning System (GPS) technology into wireless devices and other wireless transceivers. The GPS system transmits at 1.575 GHz, and the cellular and PCS systems transmit at 900 MHz and 1.9 GHz, respectively. Inherent in a device that combines GPS reception and wireless transmission circuitry, which circuitry includes an antenna, undesired electromagnetic coupling between the transmitter of the wireless transceiver and the GPS receiver will occur. Since cellular devices (handsets) are typically small in size, it is desirable to have a device that can share an antenna for use by both the GPS receiver and the wireless transceiver, if this is possible without deleterious performance effects on either system. [0007] Since the cellular and PCS transmitted signals are extremely strong signals relative to the GPS received signals, and these strong signals or their harmonics can degrade the sensitivity of the GPS receiver during wireless transceiver transmission, unless filtering or other methods are employed to reject the interfering or jamming signal. As such, the reliability and operation of GPS receivers that are used in conjunction with cellular handsets is degraded. [0008] It can be seen, then, that there is a need in the art for a method of reducing the effects of wireless transmissions on proximate GPS receivers. It can also be seen that there is a need in the art for an apparatus that can reduce the effects of wireless transmissions on GPS receivers. It can also be seen that there is a need in the art for a method and apparatus that can allow GPS receivers and wireless transmitters to share a common antenna. SUMMARY OF THE INVENTION [0009] To minimize the limitations in the prior art, and to minimize other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method and apparatus for minimizing the interference between wireless transmissions and the proximate or co-located GPS receiver. By feedforward of a phase and amplitude adjusted version of the transmitted signal and combining said signal with the composite signal at the input of the GPS receiver, the GPS receiver sensitivity degradation is reduced or eliminated in the case of perfect cancellation, and the GPS receiver is not jammed by the wireless transmissions. Further, a single antenna can be used for GPS reception and wireless transmission and reception without unduly complicating the diplexing/filtering network required to separate the multiple signals being transmitted and/or received by the single antenna. [0010] An apparatus in accordance with the present invention comprises a GPS receiver, an antenna, coupled to the GPS receiver, a transceiver, a second antenna, coupled to the transceiver, coupling means, and a phase and gain adjusting means. The coupling means obtains a replica signal from the transceiver, which is selectively phase and gain adjusted and then is provided to the GPS receiver. The selectively phase and gain adjusted replica signal reduces interference between a transmitted signal from the transceiver and a signal received by the GPS receiver. [0011] It is an object of the present invention to provide a method of reducing the effects of wireless transmissions on proximate GPS receivers. It is another object of the present invention to provide an apparatus that can reduce the effects of wireless transmissions on GPS receivers. It is a further object of the present invention to provide a method and apparatus that allows GPS receivers and wireless transceivers to share a common antenna. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Referring now to the drawings in which like reference numbers represent corresponding parts throughout: [0013] FIG. 1 illustrates the electromagnetic interference between the wireless and the GPS systems; [0014] FIG. 2 illustrates a system in accordance with the present invention; and [0015] FIG. 3 is a flowchart illustrating the steps used to practice the present invention. DETAILED DESCRIPTION OF THE DRAWINGS [0016] In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Overview [0017] It is a known problem that strong signals that fall within or near the GPS RF band will desensitize GPS receiver performance. Since cellular/PCS transmissions can introduce spurrious signals, or overdrive the GPS receiver, solving and/or minimizing the effects of such signals is of special interest for wireless handsets which contain a GPS receiver that must operate during a wireless transmission. Typically in such handsets, the wireless antenna and the GPS antenna are in close proximity or, preferably for low cost, are the same antenna, and the coupling of transmitted power is significant and likely to degrade GPS performance. The present invention describes a method of avoiding or greatly reducing the degree of GPS desensitization that occurs. [0018] Although described herein with respect to cellular/PCS interference with GPS receivers, the interference phenomenon is present for any signals that are of a frequency near or within the GPS receiver band, as well as signals that have harmonics that fall near or within the GPS receiver band, or any signals that degrade the GPS receiver. The present invention is not limited to cellular and/or PCS applications, but can be used to reduce or eliminate the degradation of GPS receiver sensitivity in other wireless transceiver and GPS receiver applications and/or environments. Continue reading about Method and apparatus for reducing gps receiver jamming during transmission in a wireless receiver... Full patent description for Method and apparatus for reducing gps receiver jamming during transmission in a wireless receiver Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method and apparatus for reducing gps receiver jamming during transmission in a wireless receiver patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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