Supporting distinct single-input single-output (SISO) services in a multiple-input multiple-output (MIMO) baseband circuit, particularly suited for a distributed antenna system (DAS)
First Claim
1. A multiple-input multiple-output (MIMO) baseband circuit configured to support distinct single-input single-output (SISO) services, comprising:
- a first MIMO path configured to distribute a first SISO signal;
a second MIMO path configured to distribute a second SISO signal;
a first quadrature modulator comprising a first SISO signal input coupled to the first MIMO path, the first SISO signal input configured to receive the first SISO signal; and
a second quadrature modulator comprising a second SISO signal input coupled to the second MIMO path, the second SISO signal input configured to receive the second SISO signal;
wherein;
the first quadrature modulator is configured to modulate the first SISO signal to a first radio frequency (RF) band based on a modulation frequency;
the second quadrature modulator is configured to modulate the second SISO signal to a second RF band based on the modulation frequency, wherein the second RF band is different from the first RF band;
the first SISO signal comprises a first in-phase (I) signal and a first quadrature (Q) signal; and
the second SISO signal comprises a second I signal and a second Q signal.
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Accused Products
Abstract
One embodiment of the disclosure relates to supporting distinct single-input single-output (SISO) services in a multiple-input multiple-output (MIMO) baseband circuit, particularly suited for a distributed antenna system (DAS). In this regard, in one aspect, two communication paths in the MIMO baseband circuit are reconfigured to distribute two distinct SISO signals. A quadrature modulator modulates the two distinct SISO signals to two different radio frequency (RF) bands, respectively, based on a modulation frequency. In another aspect, the two or more distinct SISO signals are provided to the quadrature modulator using two intermediate frequencies (IFs) that are determined based on the center frequencies and bandwidths of the two different RF bands. By reconfiguring the MIMO baseband circuit to distribute the two distinct SISO signals, it is possible to retro-support new wireless communication services and/or new RF bands in existing DAS installations without replacing the MIMO baseband circuit.
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Citations
18 Claims
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1. A multiple-input multiple-output (MIMO) baseband circuit configured to support distinct single-input single-output (SISO) services, comprising:
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a first MIMO path configured to distribute a first SISO signal; a second MIMO path configured to distribute a second SISO signal; a first quadrature modulator comprising a first SISO signal input coupled to the first MIMO path, the first SISO signal input configured to receive the first SISO signal; and a second quadrature modulator comprising a second SISO signal input coupled to the second MIMO path, the second SISO signal input configured to receive the second SISO signal; wherein; the first quadrature modulator is configured to modulate the first SISO signal to a first radio frequency (RF) band based on a modulation frequency; the second quadrature modulator is configured to modulate the second SISO signal to a second RF band based on the modulation frequency, wherein the second RF band is different from the first RF band; the first SISO signal comprises a first in-phase (I) signal and a first quadrature (Q) signal; and the second SISO signal comprises a second I signal and a second Q signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wireless communications system, comprising:
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a plurality of remote antenna units (RAUs) communicatively coupled to an optical fiber-based communications medium; wherein at least one RAU among the plurality of RAUs comprises an adaptive multiple-input multiple-output (MIMO) communications system configured to; receive and modulate a first single-input single-output (SISO) signal to generate a first radio frequency (RF) signal for distribution on a first RF band; and receive and modulate a second SISO signal to generate a second RF signal for distribution on a second RF band that is different from the first RF band, the adaptive MIMO communications system comprising a MIMO baseband circuit comprising; a first MIMO path configured to distribute the first SISO signal; a second MIMO path configured to distribute the second SISO signal; a first quadrature modulator comprising a first SISO signal input coupled to the first MIMO path, the first SISO signal input configured to receive the first SISO signal; and a second quadrature modulator comprising a second SISO signal input coupled to the second MIMO path, the second SISO signal input configured to receive the second SISO signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification