최소 단어 이상 선택하여야 합니다.
최대 10 단어까지만 선택 가능합니다.
다음과 같은 기능을 한번의 로그인으로 사용 할 수 있습니다.
NTIS 바로가기다음과 같은 기능을 한번의 로그인으로 사용 할 수 있습니다.
DataON 바로가기다음과 같은 기능을 한번의 로그인으로 사용 할 수 있습니다.
Edison 바로가기다음과 같은 기능을 한번의 로그인으로 사용 할 수 있습니다.
Kafe 바로가기국가/구분 | United States(US) Patent 등록 |
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국제특허분류(IPC7판) |
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출원번호 | US-0447014 (2014-07-30) |
등록번호 | US-9525472 (2016-12-20) |
발명자 / 주소 |
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 | 피인용 횟수 : 5 인용 특허 : 489 |
Components, systems, and methods for reducing location-dependent destructive interference in distributed antenna systems operating in multiple-input, multiple-output (MIMO) configuration are disclosed. Interference is defined as issues with received MIMO communications signals that can cause a MIMO
Components, systems, and methods for reducing location-dependent destructive interference in distributed antenna systems operating in multiple-input, multiple-output (MIMO) configuration are disclosed. Interference is defined as issues with received MIMO communications signals that can cause a MIMO algorithm to not be able to solve a channel matrix for MIMO communications signals received by MIMO receivers in client devices. These issues may be caused by lack of separation (i.e., phase, amplitude) in the received MIMO communications signals. Thus, to provide amplitude separation of received MIMO communications signals, multiple MIMO transmitters are each configured to employ multiple transmitter antennas, which are each configured to transmit in different polarization states. In certain embodiments, one of the MIMO communications signals is amplitude adjusted in one of the polarization states to provide amplitude separation between received MIMO communications signals. In other embodiments, multiple transmitter antennas in a MIMO transmitter can be offset to provide amplitude separation.
1. A multiple-input, multiple-output (MIMO) remote unit configured to wirelessly distribute MIMO communications signals to wireless client devices in a distributed antenna system, comprising: a first MIMO transmitter comprising: a first MIMO transmitter antenna configured to transmit MIMO communicat
1. A multiple-input, multiple-output (MIMO) remote unit configured to wirelessly distribute MIMO communications signals to wireless client devices in a distributed antenna system, comprising: a first MIMO transmitter comprising: a first MIMO transmitter antenna configured to transmit MIMO communications signals in a first polarization and a second MIMO transmitter antenna configured to transmit MIMO communications signals in a second polarization different from the first polarization;a second MIMO transmitter comprising a third MIMO transmitter antenna configured to transmit MIMO communications signals in the first polarization and a fourth MIMO transmitter antenna configured to transmit MIMO communications signals in the second polarization;the first MIMO transmitter configured to: receive a first downlink MIMO communications signal at a first amplitude over a first downlink communications medium, and transmit the first downlink MIMO communications signal wirelessly as a first electrical downlink MIMO communications signal over the first MIMO transmitter antenna in the first polarization; andreceive a second downlink MIMO communications signal at the first amplitude over a second downlink communications medium, and transmit the second downlink MIMO communications signal wirelessly as a second electrical downlink MIMO communications signal over the second MIMO transmitter antenna in the second polarization;the second MIMO transmitter configured to: receive a third downlink MIMO communications signal at the first amplitude over a third downlink communications medium, and transmit the third downlink MIMO communications signal wirelessly as a third electrical downlink MIMO communications signal over the third MIMO transmitter antenna in the first polarization; andreceive a fourth downlink MIMO communications signal over a fourth downlink communications medium, and transmit the fourth downlink MIMO communications signal at a second amplitude modified from the first amplitude, wirelessly as a fourth electrical downlink MIMO communications signal over the fourth MIMO transmitter antenna in the second polarization. 2. The remote unit of claim 1, wherein: the first MIMO transmitter is further configured to transmit the first downlink MIMO communications signal and second downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client; andthe second MIMO transmitter is configured to transmit the third MIMO communications signal and fourth downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client. 3. The remote unit of claim 1, further comprising at least one amplitude adjustment circuit configured to amplitude adjust the fourth downlink MIMO communications signal at the second amplitude. 4. The remote unit of claim 3, wherein the at least one amplitude adjustment circuit is further configured to be electronically tunable to adjust the fourth downlink MIMO communications signal at the second amplitude. 5. The remote unit of claim 3, wherein the amplitude adjustment circuit is configured to attenuate the fourth downlink MIMO communications signal at the second amplitude. 6. The remote unit of claim 3, wherein the amplitude adjustment circuit is configured to amplify the fourth downlink MIMO communications signal at the second amplitude. 7. The remote unit of claim 3, wherein the amplitude adjustment circuit is configured to adjust bias signal of a laser diode to provide amplitude adjustment. 8. The remote unit of claim 3, wherein the amplitude adjustment circuit is configured to adjust a bias signal of an optical modulator to amplitude adjust the fourth downlink MIMO communications signal at the second amplitude. 9. The remote unit of claim 1, wherein the second MIMO transmitter is configured to receive the fourth downlink MIMO communications signal at the second amplitude as a result of an amplitude adjustment of the fourth downlink MIMO communications signal in a central unit. 10. The remote unit of claim 1, wherein the second MIMO transmitter is configured to receive the fourth downlink MIMO communications signal in the second amplitude as a result of an amplitude adjustment of the fourth downlink MIMO communications signal in the fourth downlink communications medium. 11. The remote unit of claim 1, wherein: the first downlink MIMO communications signal further comprises a first optical downlink MIMO communications signal;the second downlink MIMO communications signal further comprises a second optical downlink MIMO communications signal;the third downlink MIMO communications signal further comprises a third optical downlink MIMO communications signal; andthe fourth downlink MIMO communications signal further comprises a fourth optical downlink MIMO communications signal. 12. The remote unit of claim 11, wherein the first MIMO transmitter further comprises: a first optical-to-electrical (O/E) converter configured to convert the first optical downlink MIMO communications signal to the first electrical downlink MIMO communications signal; anda second optical-to-electrical (O/E) converter configured to convert the second optical downlink MIMO communications signal to the second electrical MIMO downlink communications signal; andthe second MIMO transmitter further comprises: a third optical-to-electrical (O/E) converter configured to convert the third optical downlink MIMO communications signal to the third electrical downlink MIMO communications signal; anda fourth optical-to-electrical (O/E) converter configured to convert the fourth optical downlink MIMO communications signal to the fourth electrical downlink MIMO communications signal. 13. The remote unit of claim 1, wherein at least one of the first electrical downlink MIMO communications signal, the second electrical downlink MIMO communications signal, the third electrical downlink MIMO communications signal, and the fourth electrical downlink MIMO communications signal include a carrier frequency having an extremely high frequency (EHF) between approximately 30 GHz and approximately 300 GHz. 14. A method of transmitting multiple-input, multiple-output (MIMO) communications signals to wireless client devices in a distributed antenna system, comprising: receiving a first downlink MIMO communications signal at a first amplitude over a first downlink communications medium;transmitting the first downlink MIMO communications signal wirelessly as a first electrical downlink MIMO communications signal over a first MIMO transmitter antenna in a first polarization; andreceiving a second downlink MIMO communications signal at the first amplitude over a second downlink communications medium;transmitting the second downlink MIMO communications signal wirelessly as a second electrical downlink MIMO communications signal over a second MIMO transmitter antenna in a second polarization;receiving a third downlink MIMO communications signal at the first amplitude over a third downlink communications medium;transmitting the third downlink MIMO communications signal wirelessly as a third electrical downlink MIMO communications signal over a third MIMO transmitter antenna in the first polarization;receiving a fourth downlink MIMO communications signal over a fourth downlink communications medium; andtransmitting the fourth downlink MIMO communications signal at a second amplitude modified from the first amplitude, wirelessly as a fourth electrical downlink MIMO communications signal over a fourth MIMO transmitter antenna in the second polarization. 15. The method of claim 14, further comprising: transmitting the first downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client;transmitting the second downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client;transmitting the third downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client; andtransmitting the fourth downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client. 16. The method of claim 14, further comprising amplitude adjusting the fourth downlink MIMO communications signal at the second amplitude. 17. The method of claim 16, further comprising receiving the fourth downlink MIMO communications signal at the second amplitude modified from the first amplitude in a central unit. 18. The method of claim 16, further comprising receiving the fourth downlink MIMO communications signal at the second amplitude modified from the first amplitude in the fourth downlink communications medium. 19. The method of claim 16, comprising amplitude adjusting the fourth downlink MIMO communications signal at the second amplitude in the second MIMO transmitter antenna. 20. A distributed antenna system for distributing multiple-input, multiple-output (MIMO) communications signals to wireless client devices, comprising: a central unit comprising a central unit transmitter configured to receive a downlink communications signal, and transmit the received downlink communications signal as a first downlink MIMO communications signal over a first downlink communications medium, a second downlink MIMO communications signal over a second downlink communications medium, a third downlink MIMO communications signal over a third downlink communications medium, and a fourth downlink MIMO communications signal over a fourth downlink communications medium; anda remote unit, comprising: a first MIMO transmitter comprising a first MIMO transmitter antenna configured to transmit MIMO communications signals in a first polarization and a second MIMO transmitter antenna configured to transmit MIMO communications signals in a second polarization different from the first polarization;a second MIMO transmitter comprising a third MIMO transmitter antenna configured to transmit MIMO communications signals in the first polarization and a fourth MIMO transmitter antenna configured to transmit MIMO communications signals in the second polarization;the first MIMO transmitter configured to: receive a first downlink MIMO communications signal at a first amplitude over a first downlink communications medium, and transmit the first downlink MIMO communications signal wirelessly as a first electrical downlink MIMO communications signal over the first MIMO transmitter antenna in the first polarization; andreceive a second downlink MIMO communications signal at the first amplitude over a second downlink communications medium, and transmit the second downlink MIMO communications signal wirelessly as a second electrical downlink MIMO communications signal over the second MIMO transmitter antenna in the second polarization;the second MIMO transmitter configured to: receive a third downlink MIMO communications signal at the first amplitude over a third downlink communications medium, and transmit the third downlink MIMO communications signal wirelessly as a third electrical downlink MIMO communications signal over the third MIMO transmitter antenna in the first polarization; andreceive a fourth downlink MIMO communications signal over a fourth downlink communications medium, and transmit the fourth downlink MIMO communications signal at a second amplitude modified from the first amplitude, wirelessly as a fourth electrical downlink MIMO communications signal over the fourth MIMO transmitter antenna in the second polarization; andat least one amplitude adjustment circuit configured to amplitude adjust the fourth downlink MIMO communications signal to the second amplitude. 21. The distributed antenna system of claim 20, wherein: the first MIMO transmitter is further configured to transmit the first downlink MIMO communications signal and second downlink MIMO communications signal wirelessly to a line-of-sight (LOS) wireless client; andthe second MIMO transmitter is configured to transmit the third downlink MIMO communications signal and fourth downlink MIMO communication signals wirelessly to a line-of-sight (LOS) wireless client. 22. The distributed antenna system of claim 20, wherein the at least one amplitude adjustment circuit is disposed in the fourth downlink communications medium.
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