Multi-channel through-wall communication system using crosstalk suppression
First Claim
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1. A method of sending signals through a barrier using multiple-input multiple-output (MIMO) channels comprising transducers and zero forcing crosstalk suppression, the method comprising the steps of:
- providing a barrier, the barrier having a transmitter assembly on a first side of the barrier and a receiver assembly on a second side of the barrier;
wherein the transmitter assembly comprises a plurality of transmit transducers coupled to the first side of the barrier;
wherein the receiver assembly comprises a plurality of receiver transducers coupled to the second side of the barrier;
wherein equal numbers of the transmit transducers and the receiver transducers are provided, and wherein each transmit transducer is paired with and axially aligned with a corresponding receiver transducer on the opposite side of the barrier;
providing a plurality of communication channels for communicating the signals through the barrier, wherein each said communication channel comprises a portion of the barrier which is located between said paired and axially aligned transmit and receiver transducers, wherein the number of communication channels is the same as the number of transmit transducer and receiver transducer pairs, and wherein two or more of the communication channels collectively form part of a MIMO signaling arrangement;
sending a transmit signal from the first side of the barrier through at least one communication channel using at least one transmit transducer;
wherein the step of sending the transmit signal from the first side of the barrier through the communication channels comprises using orthogonal frequency division multiplexing (OFDM); and
wherein using OFDM comprises sending the signals on a plurality of subcarriers;
receiving a receive signal vector at the receiver transducers;
determining a channel gain matrix H for the plurality of communication channels which are part of the MIMO signaling arrangement;
using zero forcing to cancel crosstalk within the MIMO signaling arrangement, wherein the step of using the zero forcing comprises scaling the receive signal vector with the inverse of the channel gain matrix H.
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Abstract
A system for communicating through a solid wall uses piezoelectric transducers in a multiple-input multiple-output configuration and applies crosstalk suppression. Methods of suppressing or avoiding crosstalk between parallel communication channels includes zero-forcing, eigenmode transmission, and least mean squared error processing. Orthogonal frequency division multiplexing can be used to increase transmission rates using many subchannels. Bit-loading can be used to maximize system performance.
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Citations
25 Claims
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1. A method of sending signals through a barrier using multiple-input multiple-output (MIMO) channels comprising transducers and zero forcing crosstalk suppression, the method comprising the steps of:
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providing a barrier, the barrier having a transmitter assembly on a first side of the barrier and a receiver assembly on a second side of the barrier; wherein the transmitter assembly comprises a plurality of transmit transducers coupled to the first side of the barrier; wherein the receiver assembly comprises a plurality of receiver transducers coupled to the second side of the barrier; wherein equal numbers of the transmit transducers and the receiver transducers are provided, and wherein each transmit transducer is paired with and axially aligned with a corresponding receiver transducer on the opposite side of the barrier; providing a plurality of communication channels for communicating the signals through the barrier, wherein each said communication channel comprises a portion of the barrier which is located between said paired and axially aligned transmit and receiver transducers, wherein the number of communication channels is the same as the number of transmit transducer and receiver transducer pairs, and wherein two or more of the communication channels collectively form part of a MIMO signaling arrangement; sending a transmit signal from the first side of the barrier through at least one communication channel using at least one transmit transducer; wherein the step of sending the transmit signal from the first side of the barrier through the communication channels comprises using orthogonal frequency division multiplexing (OFDM); and wherein using OFDM comprises sending the signals on a plurality of subcarriers; receiving a receive signal vector at the receiver transducers; determining a channel gain matrix H for the plurality of communication channels which are part of the MIMO signaling arrangement; using zero forcing to cancel crosstalk within the MIMO signaling arrangement, wherein the step of using the zero forcing comprises scaling the receive signal vector with the inverse of the channel gain matrix H. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of sending signals through a barrier using multiple-input multiple-output (MIMO) channels comprising transducers and eigenmode transmission, the method comprising the steps of:
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providing a barrier, the barrier having a transmitter assembly on a first side of the barrier and a receiver assembly on a second side of the barrier; wherein the transmitter assembly comprises a plurality of transmit transducers coupled to the first side of the barrier; wherein the receiver assembly comprises a plurality of receiver transducers coupled to the second side of the barrier; wherein equal numbers of the transmit transducers and the receiver transducers are provided, and wherein each transmit transducer is paired with and axially aligned with a corresponding receiver transducer on the opposite side of the barrier; providing a plurality of communication channels for communicating the signals through the barrier, wherein each communication channel comprises a portion of the barrier which is located between said paired and axially aligned transmit and receiver transducers, wherein the number of communication channels is the same as the number of transmit transducers and the number of receiver transducers, and wherein two or more of the communication channels collectively form a MIMO signaling arrangement; providing a transmit signal vector x; multiplying the transmit signal vector x by a precoding matrix to produce a linearly transformed input vector; transmitting the linearly transformed input vector from the first side of the barrier through the barrier using the MIMO signaling arrangement, wherein the communication channels making up the MIMO signaling arrangement are mathematically represented by a channel gain matrix H; wherein the step of transmitting the linearly transformed input vector from the first side of the barrier through the barrier comprises using orthogonal frequency division multiplexing (OFDM); and wherein using OFDM comprises sending the signals on a plurality of subcarriers; the receiver assembly receiving the linearly transformed input vector as a received signal vector at the second side of the barrier; and shaping the received signal vector by performing a linear transformation on the received signal vector using a receiver shaping matrix and thereby producing an output signal vector. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of sending signals through a barrier using multiple-input multiple-output (MIMO) channels comprising transducers and using minimum mean-squared error (MMSE) crosstalk suppression, the method comprising the steps of:
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providing a barrier, the barrier having a transmitter assembly on a first side of the barrier and a receiver assembly on a second side of the barrier; wherein the transmitter assembly comprises a plurality of transmit transducers coupled to the first side of the barrier; wherein the receiver assembly comprises a plurality of receiver transducers coupled to the second side of the barrier; wherein equal numbers of the transmit transducers and the receiver transducers are provided, and wherein each transmit transducer is paired with and axially aligned with a corresponding receiver transducer on the opposite side of the barrier; providing a plurality of communication channels for communicating the signals through the barrier, wherein each communication channel comprises a portion of the barrier which is located between said paired and axially aligned transmit and receiver transducers, wherein the number of communication channels is the same as the number of transmit transducer and receiver transducer pairs, and wherein a plurality of the communication channels collectively form a MIMO signaling arrangement; sending a transmit signal vector from the first side of the barrier through at least one communication channel using at least one transmit transducer; wherein the step of transmitting the linearly transformed input vector from the first side of the barrier through the barrier comprises using orthogonal frequency division multiplexing (OFDM); and wherein using OFDM comprises sending the signals on a plurality of subcarriers; receiving a receive signal vector at the receiver transducers; determining a weight matrix W for the plurality of communication channels which are part of the MIMO signaling arrangement; and using minimum mean-squared error processing to cancel crosstalk within the MIMO signaling arrangement, wherein the step of using the minimum mean-squared error processing to cancel crosstalk comprises scaling the receive signal vector with the weight matrix W. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method of sending signals through a barrier using multiple-input multiple-output (MIMO) channels comprising transducers and crosstalk suppression, the method comprising the steps of:
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providing a barrier, the barrier having a transmitter assembly on a first side of the barrier and a receiver assembly on a second side of the barrier; wherein the transmitter assembly comprises a plurality of transmit transducers coupled to the first side of the barrier; wherein the receiver assembly comprises a plurality of receiver transducers coupled to the second side of the barrier; wherein equal numbers of the transmit transducers and the receiver transducers are provided, and wherein each transmit transducer is paired with and axially aligned with a corresponding receiver transducer on the opposite side of the barrier; providing a plurality of communication channels for communicating signals through the barrier, wherein each communication channel comprises a portion of the barrier which is located between said paired and axially aligned transmit and receiver transducers, wherein the number of communication channels is the same as the number of transmit transducer and receiver transducer pairs, and wherein two or more of the communication channels collectively form part of a MIMO signaling arrangement; sending a transmit signal from the first side of the barrier through at least one communication channel using at least one transmit transducer; wherein the step of transmitting the linearly transformed input vector from the first side of the barrier through the barrier comprises using orthogonal frequency division multiplexing (OFDM); and wherein using OFDM comprises sending the signals on a plurality of subcarriers; receiving a receive signal vector at the receiver transducers; and reducing cross-talk among the transmit and receive signals. - View Dependent Claims (25)
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Specification