Interference attenuation at the northern port in a full-duplex (FDX) amplifier

Abstract

A method comprising: receiving, by a device, an input signal containing data for amplification and retransmission, and interference from one or more additional devices; modifying the input signal by the device by applying attenuation to each of one or more frequency sub-bands, the attenuation being based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; and retransmitting the modified input signal by the device, wherein the application of attenuation to the input signal further comprises converting the input signal from a time domain to a frequency domain, multiplying each sub-band of the frequency domain signal by a weight, and converting the frequency domain signal from the frequency domain to the time domain.

Description

[0001] This application claims the benefit and priority of the preliminary US application No. 63 / 299,658, filed on January 14, 2022, entitled "North Port Interference Mitigation in a Full Duplex (FDX) Amplifier", which is incorporated herein in its entirety by reference.

[0002] The present disclosure relates generally to systems and methods for broadband network communications.

[0003] New implementations of broadband communication systems use full-duplex (FDX) communications with simultaneous upstream and downstream transmissions within the same spectrum. FDX amplifiers can be used in such systems to provide services such as retransmission or re-broadcasting signals between devices. These amplifiers can be susceptible to interference from various noise sources, which can impair operation and throughput.

[0004] According to one aspect, a procedure is provided which exhibits: Receiving, by a device, an input signal containing data for amplification and retransmission, and interference from one or more additional devices; Modifying the input signal by the device by applying attenuation for each of one or more frequency sub-bands, wherein the attenuation is based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; and Retransmission of the modified input signal by the device.

[0005] Advantageously, the one or more additional devices have one or more downstream devices, and the interference involves interference from re-upstream transmissions of data from the one or more downstream devices through the device.

[0006] Advantageously, the one or more additional devices have one or more upstream devices, and the interference exhibits leakage of upstream transmissions from the one or more upstream devices into a downstream signal.

[0007] Furthermore, applying attenuation to the input signal has the advantage of converting the input signal from a time domain to a frequency domain, multiplying each subband of the frequency domain signal by a weight, and converting the input signal from the frequency domain to the time domain.

[0008] The method also advantageously involves calculating a weight for each of the one or more frequency sub-bands proportional to a difference between the energy of the input signal and the energy of the reference signal for the corresponding frequency sub-band.

[0009] The application of attenuation to the input signal is advantageously carried out in response to the fact that the energy of the input signal exceeds a corresponding threshold for one or more frequency sub-bands.

[0010] The method also advantageously features the determination of each sub-band energy threshold for one or more frequency sub-bands by the device based on the reference signal.

[0011] The procedure also has the following advantages: Receiving the reference signal by the device; and The device measures the amount of energy of the reference signal for each of the one or more frequency sub-bands.

[0012] Furthermore, receiving the reference signal has the advantage of receiving the reference signal during a period in which one or more additional devices are not transmitting.

[0013] Advantageously, the device is designed for simultaneous upstream and downstream transmissions within a frequency range, wherein one or more additional devices include cable modems, fiber nodes or converged cable access platform (CCAP) devices.

[0014] According to one aspect, a circuit is provided which features: an input configured to receive an input signal containing data for retransmission and interference from one or more additional devices; a first sub-circuit configured to determine an attenuation amount to be applied to each of one or more frequency sub-bands of the input signal, wherein the attenuation is based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; a second sub-circuit configured to apply the specified attenuation amount to each of the one or more frequency sub-bands; and an output configured to retransmit the attenuated input signal.

[0015] Advantageously, the one or more additional devices have one or more downstream devices, wherein the interference is caused by re-upstream transmissions of data from the one or more downstream devices.

[0016] Advantageously, the one or more additional devices have one or more upstream devices, wherein the interference includes leakage of upstream transmissions from the one or more upstream devices into a downstream signal.

[0017] Advantageously, the circuit also features a third sub-circuit between the input and the first sub-circuit, which is configured to convert the input signal from a time domain to a frequency domain.

[0018] Advantageously, the second sub-circuit is configured to multiply each sub-band of the frequency domain by a weight.

[0019] Advantageously, the first sub-circuit is configured to calculate a weight for each of the one or more frequency sub-bands proportional to a difference between the energy of the input signal and the energy of the reference signal for the corresponding frequency sub-band.

[0020] Advantageously, the circuit also features a fourth sub-circuit between the second sub-circuit and the output, which is configured to convert the frequency domain signal into the time domain.

[0021] Advantageously, the second sub-circuit is configured to apply damping in response to the fact that the energy of the input signal for one or more frequency sub-bands exceeds a corresponding sub-band energy threshold, which is determined based on the reference signal.

[0022] Advantageously, the first sub-circuit is further configured to receive the reference signal and to measure the energy of the reference signal for each of the one or more frequency sub-bands.

[0023] Advantageously, the first sub-circuit is further configured to receive the reference signal during a period in which one or more additional devices are not transmitting. List of characters

[0024] The patent or application file contains at least one drawing in color. Copies of this patent or application publication with color drawing(s) will be provided by the Office upon request and payment of the required fee.

[0025] Various tasks, aspects, features, and advantages of the present disclosure become apparent and are better understood with reference to the detailed description in conjunction with the accompanying drawings, in which identical reference numerals denote corresponding elements. In the drawings, identical reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Fig. 1A is a block diagram showing an implementation of a broadband transmission system; Fig. Figure 1B is a block diagram showing an implementation of a broadband transmission system with interference groups; Fig. 1C is a representation that shows an implementation of Resource Block Assignments (RBAs) for interference groups; Fig. 2A is a block diagram of an implementation of an FDX repeater or amplifier; Fig. Figure 2B is a representation of the sources of CM and repeater self-interference according to some implementations; Fig. Figures 3A-3C are graphs showing downstream noise reduction examples according to some implementations; Fig. Figure 4A is a block diagram of an implementation of a downstream interference suppression system; Fig. Figure 4B is a block diagram of an exemplary implementation of processing during downstream interference suppression; Fig. 4C is a flowchart of a procedure for interference detection and attenuation according to some implementations; Fig. 5A is a block diagram showing an embodiment of a network environment having one or more access points connected to one or more devices or stations; and Fig. 5B and Fig. 5C are block diagrams showing embodiments of computer devices that are useful in conjunction with the methods and systems described herein.

[0026] Details of various embodiments of the methods and systems are set out in the attached drawings and the description below. Detailed description

[0027] The following standard(s), including any draft versions thereof, are incorporated herein by reference in their entirety and form part of this disclosure in every respect: DOCSIS 3.0, DOCSIS 3.1, and DOCSIS 4.0, published by Cable Television Laboratories, Inc. (CableLabs), Louisville, Colorado. Although this disclosure may refer to aspects of this standard, it is in no way limited by it.

[0028] To understand the description of the various embodiments below, the following descriptions of the sections of the description and their respective contents may be helpful: - Section A describes embodiments of systems and methods for interference attenuation at the northern port in an FDX amplifier; and - Section B describes a network environment and a computer environment that may be useful for carrying out the embodiments described herein. A. Systems and methods for interference attenuation

[0029] New implementations of broadband communication systems use full-duplex (FDX) communications with simultaneous upstream and downstream transmissions within the same spectrum. FDX amplifiers can be used in such systems to provide services such as retransmission or re-broadcasting signals between devices. These amplifiers can be susceptible to interference from various noise sources, which can impair operation and throughput. In particular, interference from desired upstream transmission signals can reach the northern port (e.g., upstream) input of the FDX amplifier with significant total power relative to the total power of the desired downstream signal. Interference can originate from various sources, including reflected upstream transmissions, cable modems, etc.Cable modem (CM) transmission leakage can occur due to finite tap-to-output isolation or other sources. In many implementations of cable taps or other nodes with three or more ports, a signal injected into one port and intended for transmission from a second port may "leak" or be transmitted at a reduced signal level through a third or other ports. This can be due to capacitive or inductive coupling between circuit elements, filters without complete attenuation, etc. The interference power on the upstream channels can fluctuate randomly depending on CM permissions, potentially affecting power amplifier (PA) nonlinearity and echo cancellation in the south port of FDX amplifiers. In many cases, interference levels can even have a higher amplitude than the desired downstream signal.This can lead to a significant difference in the total input power of the northern port, depending on whether the upstream amplifier is transmitting or not. Without attenuation, these power fluctuations can propagate to the southern port (in many implementations with some additional phase and / or frequency skew), resulting in: compression and / or clipping at the southern port of the PA due to increased downstream transmit power when upstream is transmitting; amplified echo at the southern port due to increased downstream transmit power, requiring additional backoff at analog front ends (AFEs) of the FDX input, and a corresponding loss of echo cancellation (EC) power.

[0030] Accordingly, implementations of the systems and methods discussed herein provide improvements in interference attenuation and cancellation. Interference attenuation or cancellation can involve the partial or complete removal, reduction, damping, or other filtering of interfering signals, noise, or energy within a communication band, thereby improving the signal-to-noise ratio, signal quality, or intelligibility of a desired signal, or otherwise improving communication throughput. In many implementations, an interference canceller can be provided in the downstream path to compensate for compound power on the FDX upstream subbands within a specified amplitude range (e.g., X dB) from the desired downstream signal on the same subband, without affecting the downstream subbands.

[0031] With reference to Fig. Figure 1A shows a block diagram of a broadband transmission system according to some implementations, comprising a node 100 (e.g., a fiber node), a first (upstream of the repeater 102) plurality of branches 130 and client devices (e.g., cable modems) 120, a repeater 102, and a second (downstream of the repeater 102) plurality of branches 130' and client devices 120'. As shown, a downstream signal 104 can be transmitted from the node and received by the repeater 102, and an upstream transmission 106 can be transmitted from a cable modem. Interference from the upstream transmission 108 can reach the repeater 102 at its input (northern) port, and accordingly, the repeater can transmit or repeat the downstream signal plus interference 112. This can lead to impaired performance for downstream and / or upstream equipment within interference group 110.

[0032] In particular, CM interference can often result from CMs 120 and 120' both south and north of FDX amplifier or repeater 102. CM signals arriving at the southern port are amplified at the northern port and retransmitted. Reflections due to finite return loss at the northern port affect the downstream signal. Similarly, CM transmissions from the northern side of the amplifier are reflected back to the northern port by the finite port-to-output loss of the nearest branch to the amplifier. While retransmission interference can potentially be resolved by echo cancellation techniques in the amplifier, echo cancellation cannot resolve leakage interference originating from the northern port.

[0033] In many implementations, providing resource block assignments (RBAs) among interference groups can help to mitigate interference, for example, to reduce or eliminate the impact of upstream interference on CMs south (e.g., downstream) of the repeater. Fig. Figure 1B, for example, is a block diagram showing an implementation of a broadband transmission system with interference groups 110A-110C, commonly referred to as interference group 110. Devices within an interference group can use the same RBA, and multiple interference groups can be assigned different RBAs to enable full-duplex transmission. An RBA can identify subbands for use in upstream or downstream transmissions. For example, in some implementations, an RBA might have a 3-bit value indicating whether a subband is used for upstream (1) or downstream (0) transmission. Subbands can each have a frequency range, which may be predefined or determined during configuration or setup, within a larger frequency range for communication.For a given bandwidth of 10 MHz for communication, the area can, for example, be divided into 10 equal subbands of 1 MHz. Subbands can have the same or different sizes depending on the implementation.

[0034] With reference to Fig. Figure 1C shows an implementation of RBA assignments for interference groups, where a first interference group is assigned RBA 101 and a second interference group is assigned RBA 010. RBAs can be dynamically reassigned to adjust the balance of downstream versus upstream transmissions for each interference group to meet demand.

[0035] Fig. Figure 2A is a block diagram of an implementation of an FDX repeater or amplifier 102, with a northern port facing cable 150A (for example, towards a fiber node) and a southern port facing cable 150B (for example, towards additional CMs). In some implementations, transmissions received by the fiber node (or other northern devices) and intended for retransmission via the southern port may be referred to as downstream transmissions. Conversely, transmissions received by southern devices and intended for retransmission to northern devices may be referred to as upstream transmissions.

[0036] In many implementations, an FDX repeater or amplifier may have echo cancellation associated with its south port, as shown. In many implementations, all CMS or other devices south of the FDX repeater or amplifier may be in the same interference group (and in many implementations have the same RBA assigned). Echo cancellation can be used to prevent upstream transmissions from these devices from being reflected back downstream. The "pure" upstream signal can be amplified and retransmitted via the north port. In many implementations, echo cancellation may not be necessary at the north port, or it may be irrelevant because CM transmissions from devices immediately north of the repeater can adversely affect all CMs south of the repeater.RBA scheduling can be used to avoid this interference.

[0037] There are several potential sources of interference within the FDX amplifier or repeater, as described in Fig. Figure 2A shows the situation with a dashed line. For example, due to the amplification loop between the northern and southern ports (1), downstream signals can be reflected and amplified. Reflected downstream signals (2) can also adversely affect upstream signals (as well as reflected residual echo interference (3)). At the northern port, reflected upstream signals and upstream transmissions from nearby devices north of the repeater can adversely affect incoming downstream signals (4). These various sources of interference can be referred to differently as self-interference, northern CM interference, northern device interference, etc.

[0038] Fig. Figure 2B shows the sources of CM reference and repeater self-reference according to some embodiments. At point P, a signal from repeater 102 and from a northerly (upstream) CM are identical because they arrive at node 100 with the same power TX_P. TX_P=CM_TX+H3+I2 TX_P=REP_TX+H2+I1

[0039] At repeater 102 input: REP_RX=TX_P−H2+I1+E CM_RX=TX_P−I2+I3+H2

[0040] Interference with CM vs. interference with REP TX: CM_RX−REP_RX=−I2+I3+2*H2+I1-E

[0041] Based on assumptions based on typical operations, E=-20dB; H2=0dB, 11=-1.5dB; I2=-8dB; I3=-23dB: CM_RX−REP_RX=8−23−1.5+203.5 dB

[0042] The northern CM interference is 3.5 dB higher than the expected self-interference.

[0043] To address these problems, some implementations may employ interference attenuation as follows. In the downstream path, the downstream power in each subband can be monitored, and increases above a predefined threshold can be detected. When an increase is detected, the power in the subband (or the affected portion of the subband) can be reduced back below the threshold. This modifies the downstream signal south of the amplifier in the affected subband(s), but no common receivers (CMs) will listen to this signal. As a reminder, all CMs 120 feet south of the repeater, plus CMs 102 feet immediately to the north, are in an interference group of 110. Therefore, none of these CMs will attempt to receive the downstream signal in the subband(s) affected by the added upstream power.In many implementations, all subbands can be monitored at any time, so the FDX amplifier does not need to know the downstream and upstream subband allocation.

[0044] Fig. Figures 3A-3C are graphs showing examples of downstream noise reduction according to some implementations. Fig. Figure 3A shows downstream received PSD or power spectral density spectrum with and without noise suppression in some implementations. Fig. Figure 3B shows an example input and output signal before and after interference suppression. Fig. Figure 3C shows the signal-to-noise ratios of adjacent downstream channels with noise reduction applied in some implementations. In the implementation shown, the full subband is analyzed, with transmissions on the third band skewed upstream as shown. In many implementations, narrowband interference may not be attenuated or may only be slightly attenuated.

[0045] As discussed above, in some cases, interference can cause compression or clipping at the southern port of the PA due to increased downstream transmit power when upstream transmission occurs. Implementations of the systems and methods discussed here address this by not increasing the downstream transmit power beyond the threshold used by the level limiter. Some additional headroom can be used at the southern port of the PA to prevent clipping, but this may be greatly reduced or eliminated in some implementations. Furthermore, increased echo at the southern port due to increased transmit power, which necessitates additional backoff at AFEs of the FDX input, and the corresponding loss of EC power, are addressed because the variation in echo level is limited by the level limiter threshold.AFEs of the FDX input only require enough additional backoff to accommodate this much smaller amount of variation, thereby greatly improving system performance.

[0046] In many implementations, the limiter can be equipped with some knowledge of the intended downstream level to know when the actual power level is out of range. The accuracy of this information can determine the limiter's threshold, which in turn determines the system's performance. For example, if an intended level X is known within 0.1 dB, then the threshold can be set to (X + 0.2 dB), and there will be very little variation in the downstream output level at the south port. If the intended level X is known within 3 dB, then the threshold can be set to (X + approximately 3 dB), which requires much more headroom and AFE backoff to accommodate large variations in downstream transmission power.Accordingly, some implementations can employ a "level learning" step to maximize accuracy, thereby reducing the threshold over time based on system performance. Levels can be learned, for example, when the FDX amplifier is first installed, whenever the frequency plan in the FDX band changes (e.g., changes to allocated FDX spectrum, adds or removes significant exclusions, adds or removes QAM channels in unallocated spectrum, etc.), at regular intervals on the order of once daily, or at any other such time. The interference attenuation processor can communicate with the Converged Cable Access Platform (CCAP) cores or a service provider to specify when the learning period will occur, because learning takes place during a quiet period upstream (e.g., during a busy period).(No CMs transmitted on a subband anywhere within the audible range) for several milliseconds (similar to a long ECTO) or any other suitable duration may be required. To further improve performance, the FDX amplifier can monitor the temperature and make necessary adjustments at the expected level.

[0047] In many implementations, interference attenuation can be applied in a multi-stage process, including setting a “reference energy” per subband equal to the desired received downstream signal energy at the subband, measuring the energy at FDX subbands and identifying subbands with energy above the reference energy by the allowed threshold of X dB, and implementing subband filters that attenuate the subband energies back to the reference energies. Fig. Figure 4A, for example, is a block diagram of an implementation of a downstream interference suppression system. As shown, input signals can be converted into digital signals via an analog-to-digital converter (ADC) 402 and equalized to flatten the received downstream frequency response via the line equalizer 404. After equalization, the signal (and any received interference) can be time-domain shaped via the former 406 to minimize interference with adjacent subbands due to sharp filters in the frequency domain. The signal can be further processed via FFT 408 or another domain converter circuit or sub-circuits (e.g., wavelet transforms, discrete Fourier transforms, sparse Fourier transforms, etc.).The signals, which may generally be called time-to-frequency domain converters, time-to-frequency domain transformers, time-to-frequency domain converter circuits, or any other similar terms, are converted into the frequency domain. The frequency domain signal can be used to measure energy on FFT bins belonging to the subbands, and in many implementations, the interference detector 410 (sometimes called a processing subcircuit, processor, or similar) computes frequency domain filter weights 412 as a function of the measured energies. Similarly, the subband energies on the signal at the equalizer output can be measured. The interference detector or processing subcircuit 410 may be hardware, software, or a combination of hardware and software.In some implementations, the interference detector or processing sub-circuits may, for example, include a digital comparator that compares a digital input signal or bitstream with a reference signal or value (e.g., by performing XOR on binary words representing sampled signal amplitudes with a reference signal amplitude or threshold amplitude, etc.). In other implementations, the interference detector may include an analog comparator with a reference level (e.g., a preset voltage level). Other combinations of analog and digital hardware and / or software may be used in various implementations to determine attenuation levels or weights, or to compare input signals with reference signals or values.

[0048] In particular, many implementations for interference detection, with F(B) as a vector of FFT bins belonging to subband B, and R(B) as a pre-calculated reference energy of subband B, are subject to the following: E(B) = sum(F(B)^2) is the measured energy per subband; and A(B) = E(B)-R(B) is the required attenuation in band B, which is used to calculate the weights corresponding to sub-band B.

[0049] To establish a reference energy level for each subband, some implementations may use a "downstream training sequence" during a period when no upstream transmissions are taking place (sometimes referred to as "quiet probes"). In many implementations, the downstream training sequence could be any downstream transmission on the FDX band with a power per subband as configured by the CCAP and used for normal downstream transmissions. During training, the reference energy of a subband in the frequency domain is measured by the interference detector 410 by summing energies from FFT bins belonging to that subband. The training signal may be received before or, in other implementations, after the domain forming 406. Training can be performed during initial installation, during changes to the downstream frequency response as described above, and during other implementations.and / or be performed regularly during training periods as configured by CCAP. In other implementations, the training sequence could be a pseudorandom sequence with a flat or known PSD or power density spectrum.

[0050] Subband filter weights are calculated so that the energy at the filter output is equal to or sufficiently close to R(B). These weights can be used with any window type, including brickwall, raised cosine, Kaiser, etc., to minimize out-of-band interference with neighboring downstream subbands in various implementations.

[0051] Frequency domain filtering can be performed on the frequency-domain-converted signal by multiplying the signal by the filter weights for each sub-band using a filter circuit or sub-circuit and re-converting to the time domain via IFFT 414 (or other time-frequency domain converter circuits or sub-circuits) as explained above. In various implementations, a filter circuit or sub-circuit may consist of software, hardware, or a combination of both. For example, in some implementations, a filter circuit or sub-circuit may include instructions for a processor to multiply digital input signal samples in a frequency domain by weights. In some implementations, a filter circuit or sub-circuit may include passive or active electronic filters (e.g., bandpass or notch filters, variable bandwidth filters, etc.).Various combinations of analog and / or digital filters can be used in different implementations. A final time-domain reconstruction block 416 can, in many implementations, apply shapes and reshaping in the time domain to minimize interference with adjacent subbands, as described above.

[0052] In many implementations, the processing and filtering sub-circuits described above can be separate sub-circuits. In other implementations, the processing and filtering sub-circuits can be part of the same circuit or sub-circuit. In many implementations, one or more components can be common to or used by the processing and filtering sub-circuits (e.g., common or shared signal buffers or memory elements, common or shared signal buses, common or shared power supply circuits or sub-circuits or elements, etc.).

[0053] Fig. Figure 4B shows an exemplary implementation of the processing during downstream interference suppression, and in particular an implementation of steps 408-414 and 416. As shown, a sliding and overlapping window can be used for signal processing by an interference suppression circuit at FFT 408, weighting 412, and iFFT 414, where each processed signal is summed with the preceding (and temporally overlapping) signal.

[0054] Fig. Figure 4C is a flowchart of a procedure for interference detection and attenuation according to several implementations. The implementation shown has a first training section 440 and a second attenuation section 442, which can be referred to as the processing or filtering section. The first training section 440 can be executed on startup or initialization, periodically (e.g., daily, hourly, etc.), dynamically (e.g., every time a signal can be used for training, for example, when interfering devices are not transmitting), manually, every time the frequency plan is changed (e.g., when spectrum allocations are changed, when exclusions are added or removed, when QAM channels are added or removed in an unallocated spectrum, etc.), or by any other such trigger.

[0055] In step 450, a device or processing circuit, such as a Repeater 102 or other such device, can receive a training or reference signal. In some implementations, the training or reference signal can be a predefined signal used only for training. In other implementations, the training or reference signal can be a standard data signal continuously transmitted by the CCAP, and training is scheduled or triggered at a time when no other devices are transmitting on any subband within a region of the device or processing circuit (e.g., devices within a certain number of branches or in an interference group, such that their transmissions could cause detectable interference).Devices outside the interference group that cannot cause sufficient interference may not be affected in many implementations and can transmit normally. Accordingly, in many such implementations, the training or reference signal can be pre-scheduled by a controller or management unit or device. The training or reference signal can be several milliseconds, tens or hundreds of milliseconds long, or any other such interval. In some implementations, other measurements (e.g., temperature) can be taken during the training period.

[0056] In step 452, the device or circuit can measure an amount of energy in a frequency subband. In some implementations, measuring the amount of energy may involve converting the signal into a frequency domain signal via an FFT or other domain converter sub-circuit and measuring an amount of energy in each of the one or more frequency bins within the subband. In step 454, a threshold for the subband may be set equal to the amount of energy in the subband, and / or the energy value may be recorded, and steps 452-454 may be repeated for each additional frequency subband. As, for example, in the context of above Fig. As described in 4A, the received signal can be converted to a digital signal via an ADC, equalized, time-domain shaped, and converted to a frequency-domain representation. The energy in the subbands can be measured, and in some implementations, the signal can be converted back to a time domain (e.g., via an IFFT), shaped, and retransmitted (not shown). Although shown as an iterative process, in many implementations steps 452 and 454 can be performed in parallel or can be performed together in series (e.g., measuring the energy for all subbands and then setting the thresholds for all subbands).

[0057] Once trained, the device can receive a signal in an attenuation section 442, at step 456. The signal can be received at a north or downstream input or upstream output port, for example, reflected from a branch north of the FDX amplifier or other device, and the signal can exhibit interference from one or more additional devices, such as cable modems south and north of the FDX amplifier. The interference can include re-upstream transmissions from downstream devices through the device and / or interference from downstream leaks from upstream transmissions from upstream devices.

[0058] In step 458, the device can measure the energy of the signal in a frequency subband, which could be an FDX subband or any other configurable frequency band. Measuring the energy may involve converting the signal to a frequency domain using an FFT or similar sub-circuit. In some implementations, additional processing, such as equalization and time-domain shaping, may be applied prior to conversion. The measured energy can be compared to a threshold value (e.g., the energy value of the training or reference signal in the corresponding subband), or the difference between the measured energy of the signal and the energy of the training or reference signal in the subband can be determined.If the difference is not zero or positive, or if the measured energy exceeds the threshold, then in step 460 an attenuation amount for the subband can be determined, or an amount (e.g., in decibels, voltage, or another applicable measure) by which the energy or signal in the subband should be reduced (e.g., via a filter, reduced gain on a subband amplifier, voltage divider, or any other type and form of attenuation circuit). As discussed above, the attenuation amount can be proportional to the difference in energy between the signal and the training or reference signal in the subband. If the energy does not exceed the threshold (or the difference is negative), then in some implementations no attenuation can be applied in the subband.For example, if a training signal that is intended to be flat has a first level in a first subband and a second level in a second subband that is 6 dB higher, then the system can determine that an attenuation of -6 dB should be applied to the second subband. The attenuation amount can be stored as part of a filter weight vector in some implementations. Steps 458-460 can be repeated for each additional subband (and can be performed in parallel for different subbands or sequentially for all subbands, as discussed above).

[0059] In step 462, the signal can be filtered in the frequency domain in some implementations. Filtering the signal can involve attenuating each subband according to specified filter weights. In one implementation, for example, the energy value in each subband exceeding the threshold can be multiplied by a corresponding filter weight so that the resulting energy value is equal to the energy of the reference signal for that subband. In step 464, the filtered signal can be retransmitted via a south port or downstream of the device. Retransmission of the signal can involve converting the signal from a frequency domain to a time domain (e.g., via an IFFT sub-circuit), applying time-domain shaping, converting the signal to an analog signal via a DAC, etc.

[0060] Steps 456-464 can be repeated for additional received signals, and in some implementations, steps 450-454 can be repeated for additional training periods, as discussed above.

[0061] In some implementations of the procedure discussed above, the FDX amplifier does not need to know the current RBA as set by the CCAP or the scheduler, or which of the FDX subbands are upstream and which are downstream. Such implementations can be used when the RBA is unknown to the FDX amplifiers, but can also be used when the RBA is known. In other implementations, if the RBA is known, an FDX subband known to be an upstream subband can be completely blocked and replaced by a downstream signal generated locally by a downstream modulator.

[0062] Accordingly, implementations of the systems and methods discussed herein provide improvements in interference attenuation and cancellation. Many implementations may include an interference canceller in the downstream path to compensate for combined power on the FDX upstream subbands within a specified amplitude range (e.g., X dB) from the desired downstream signal on the same subband, without affecting the downstream subbands.

[0063] In one aspect, the present disclosure relates to a method for interference attenuation. The method comprises receiving, by a device, an input signal containing data for retransmission and interference by one or more additional devices. The method also comprises modifying the input signal by the device by applying attenuation to the input signal for each of one or more frequency sub-bands, the attenuation being based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band. The method also comprises retransmitting the modified input signal by the device.

[0064] In some implementations, the one or more additional devices include one or more downstream devices, and the interference involves re-upstream transmissions of data from the one or more downstream devices through the device. In other implementations, the one or more additional devices include one or more upstream devices, and the interference involves downstream leakage of upstream transmissions from the one or more upstream devices. The additional devices may include common modules (CMs), fiber nodes, additional repeaters or amplifiers, capacitive coupling devices (CCAPs), or any other type and form of device.

[0065] In some implementations, the method involves converting the input signal from a time domain to a frequency domain, multiplying each subband of the frequency domain signal by a subband weight, and converting the input signal back from the frequency domain to the time domain. In another implementation, the method involves calculating a subband weight for each of the one or more frequency subbands proportional to the difference between the energy of the input signal and the energy of the reference signal for the corresponding frequency subband.

[0066] In some implementations, attenuation is applied to the input signal in response to the input signal's energy exceeding a corresponding subband energy threshold for one or more frequency subbands. In another implementation, the method involves the device determining each subband energy threshold for the one or more frequency subbands based on the reference signal.

[0067] In some implementations, the method involves the device receiving the reference signal and measuring the energy of the reference signal for each of the one or more frequency subbands. In another implementation, the method involves receiving the reference signal during a period when the one or more additional devices are not transmitting.

[0068] In some embodiments, the device includes a full-duplex amplifier, and one or more additional devices include cable modems.

[0069] In another aspect, the present disclosure relates to an interference attenuation circuit. The circuit comprises an input configured to receive an input signal containing data for retransmission and interference from one or more additional devices; a processing sub-circuit configured to determine an attenuation amount to be applied to each of one or more frequency sub-bands of the input signal, the attenuation being based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; a filter sub-circuit configured to apply the determined attenuation amount to each of the one or more frequency sub-bands; and an output configured to retransmit the attenuated input signal.

[0070] In some implementations, the one or more additional devices have one or more downstream devices, and the interference involves re-upstream transmissions of data from the one or more downstream devices. In some implementations, the one or more additional devices have one or more upstream devices, and the interference involves downstream leakage of upstream transmissions from the one or more upstream devices.

[0071] In some implementations, the input is connected to a time-domain converter, with the processing sub-circuit receiving the input signal in the frequency domain. In another implementation, the filter sub-circuit is configured to multiply each sub-band of the frequency domain signal by a sub-band weight. In yet another implementation, the processing sub-circuit is configured to calculate a sub-band weight for each of the one or more frequency sub-bands proportional to a difference between the energy of the input signal and the energy of the reference signal for the corresponding frequency sub-band. In a still further implementation, the filter sub-circuit is connected to a frequency-to-time domain converter or FFT.

[0072] In some implementations, the filter sub-circuit is configured to apply attenuation in response to the fact that the energy of the input signal for one or more frequency sub-bands exceeds a corresponding sub-band energy threshold, which is determined based on the reference signal.

[0073] In some implementations, the processing sub-circuit is further configured to receive the reference signal and measure the energy of the reference signal for each of the one or more frequency sub-bands. In another implementation, the processing sub-circuit is further configured to receive the reference signal during a period when the one or more additional devices are not transmitting. B. Computer and network environment

[0074] After discussing specific embodiments of the present solution, it may be helpful to describe aspects of the operating environment and associated system components (e.g., hardware elements) in connection with the methods and systems described herein. With reference to Fig. Figure 5A shows an embodiment of a network environment. In brief, the network environment comprises a wireless communication system including one or more access points 506, one or more wireless communication devices 502, and a network hardware component 592. The wireless communication devices 502 may, for example, be laptop computers 502, tablets 502, personal computers 502, and / or mobile phones 502. The details of an embodiment of each wireless communication device and / or access point are described in more detail in Figure 5A. Fig. 5B and Fig. 5C described. In one embodiment, the network environment can be an ad hoc network environment, a wireless network environment infrastructure, a subnet environment, etc.

[0075] The access points (APs) 506 can be operationally connected to the network hardware 592 via LAN connections. The network hardware 592, which may include a router, gateway, switch, bridge, modem, system controller, device, etc., can provide a LAN connection for the communication system. Each access point 506 can have an associated antenna or antenna array to communicate with the wireless communication devices 502 within its range. The wireless communication devices 502 can register with a specific access point 506 to receive services from the communication system (e.g., via a SU-MIMO or MU-MIMO configuration). For direct connections (e.g., point-to-point communications), some wireless communication devices 502 can communicate directly over an assigned channel and communication protocol.Some of the wireless communication devices 502 can be mobile or relatively static with respect to the access point 506.

[0076] In some embodiments, an access point 506 includes a device or module (including a combination of hardware and software) that enables wireless communication devices 502 to connect to a wired network using Wi-Fi or other standards. An access point 506 may sometimes be referred to as a wireless access point (WAP). An access point 506 may be configured, designed, and / or constructed to operate in a wireless local area network (WLAN). In some embodiments, an access point 506 may connect to a router (e.g., via a wired network) as a standalone device. In other embodiments, an access point may be a component of a router. An access point 506 may provide access to a network for multiple devices 502.For example, a 506 access point can connect to a wired Ethernet connection and provide wireless connections to other 502 devices using radio frequency links to utilize that wired connection. A 506 access point can be built and / or configured to support a standard for sending and receiving data using one or more radio frequencies. These standards, and the frequencies they use, can be defined by IEEE (e.g., IEEE 802.11 standards). An access point can be configured and / or used to support public internet hotspots and / or within an indoor network to extend the Wi-Fi signal range of the network.

[0077] In some embodiments, the access points 506 (e.g., in the house or building) can be used for wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee, any other type of radio frequency-based network protocol, and / or variations thereof). Each of the wireless communication devices 502 can have built-in radio and / or be connected to a radio. Such wireless communication devices 502 and / or access points 506 can operate according to the various aspects of the disclosure presented herein to increase performance, reduce costs and / or size, and / or improve broadband applications. All wireless communication devices 502 can have the capability to act as client nodes, seeking access to resources (e.g., data) and connections to network nodes such as servers via one or more access points 506.

[0078] The network connections can be of any type and / or form and can be any of the following: a point-to-point network, a broadcast network, a telecommunications network, a data communications network, or a computer network. The network topology can be a bus, star, or ring topology. The network can be of any network topology known to those skilled in the art who are able to support the operations described herein. In some embodiments, different types of data can be transmitted over different protocols. In other embodiments, the same types of data can be transmitted over different protocols.

[0079] The communication device(s) 502 and the access point(s) 506 may be installed and / or run on any type and form of computing device, such as a computer, a network device or a device capable of communicating on any type and form of network and performing the operations described herein. Fig. 5B and Fig. Figure 5C shows block diagrams of a computer device 500 that is useful for carrying out an embodiment of the wireless communication devices 502 or the access point 506. As shown in Fig. 5B and Fig. As shown in Figure 5C, each computer device 500 has a central processing unit 521 and a main memory unit 522. As shown in Figure 5C, each computer device 500 has a central processing unit 521 and a main memory unit 522. Fig. As shown in Figure 5B, a computer device 500 can include a storage device 528, an installation device 516, a network interface 518, an I / O controller 523, display devices 524a-524n, a keyboard 526, and a pointing device 527, such as a mouse. The storage device 528 can, without limitation, include an operating system and / or software. As shown in Fig. As shown in Figure 5C, each computing device 500 may also include additional optional elements, such as a memory port 503, a bridge 570, one or more input / output devices 530a-530n (generally indicated by reference numeral 530) and a cache memory 540, which are connected to the central computing unit 521.

[0080] The central processing unit 521 is any logic circuit that responds to and processes instructions fetched from the main memory unit 522. In many embodiments, the central processing unit 521 is provided by a microprocessor unit, such as those manufactured by Intel Corporation, Mountain View, California; those manufactured by International Business Machines, White Plains, New York; or those manufactured by Advanced Micro Devices, Sunnyvale, California. The computing device 500 may be based on any of these processors, or on any other processor capable of operating as described herein.

[0081] The main memory unit 522 can be one or more memory chips capable of storing data and allowing the microprocessor 521 to directly access any memory location, such as any type or variant of Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Ferroelectric RAM (FRAM), NAND Flash, NOR Flash, and Solid State Drives (SSD). The main memory 522 can be based on any of the memory chips described above, or any other memory chip capable of operating as described herein. In the Fig. In the embodiment shown in 5B, the processor 521 communicates with the main memory 522 via a system bus 550 (described in more detail below). Fig. Figure 5C shows an embodiment of a computer device 500 in which the processor communicates directly with the main memory 522 via a memory port 503. Fig. 5C could be the main memory 522, for example a DRDRAM.

[0082] Fig. Figure 5C shows an embodiment in which the main processor 521 communicates directly with the cache memory 540 via a secondary bus, sometimes referred to as the backside bus. In other embodiments, the main processor 521 communicates with the cache memory 540 using the system bus 550. The cache memory 540 typically has a faster response time than the main memory 522 and is provided, for example, by SRAM, BSRAM, or EDRAM. In the embodiment shown in Fig. In the embodiment shown in Figure 5C, the processor 521 communicates with various I / O devices 530 via a local system bus 550. Different buses can be used to connect the central processing unit 521 to any of the I / O devices 530, for example, a VESA VL bus, an ISA bus, an EISA bus, a MicroChannel Architecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or a NuBus. For embodiments where the I / O device is a video display 524, the processor 521 can use an Advanced Graphics Port (AGP) to communicate with the display 524. Fig. Figure 5C shows an embodiment of a computer 500 in which the main processor 521 can communicate directly with the I / O device 530b, for example via HYPERTRANSPORT, RAPIDIO or INFINIBAND communication technology. Fig. Figure 5C also shows an embodiment in which local buses and direct communication are mixed: The processor 521 communicates with the I / O device 530a using a local interconnect bus, while it communicates directly with the I / O device 530b.

[0083] A wide variety of I / O devices 530a-530n can be present in the computer device 500. Input devices include keyboards, mice, keypads, trackballs, microphones, rotary dials, touchpads, touchscreens, and graphics tablets. Output devices include video displays, loudspeakers, inkjet printers, laser printers, projectors, and dye-sublimation printers. The I / O devices can be controlled by an I / O controller 523, as shown in Fig. Figure 5B shows the I / O controller can control one or more I / O devices, such as a keyboard 526 and a pointing device 527, for example, a mouse or an optical pen. Furthermore, an I / O device can also provide memory and / or an installation medium 516 for the computer device 500. In other embodiments, the computer device 500 can provide USB connections (not shown) to accommodate portable USB storage devices, such as the USB Flash Driver Line of devices manufactured by Twintech Industry, Inc., Los Alamitos, California.

[0084] With further reference to Fig. 5B The computer device 500 can support any suitable installation device 516, such as a floppy disk drive, a CD-ROM drive, a CD-R / RW drive, a DVD-ROM drive, a flash memory drive, tape drives of various formats, a USB device, a hard disk, a network interface, or any other device suitable for installing software and programs. The computer device 500 can further include a storage device, such as one or more hard disk drives or redundant arrangements of independent disks, for storing an operating system and other related software, and for storing application software programs, such as any program or software 520 for implementing the systems and procedures described herein (e.g., configured and / or designed for them).Optionally, any of the 516 installation devices could also be used as a storage device. Furthermore, the operating system and software could be run from a bootable medium.

[0085] Furthermore, the computer device 500 may have a network interface 518 to connect to the network 504 through a variety of connections, including but not limited to standard telephone lines, LAN or WAN connections (e.g., 802.11, T1, T3, 56kb, X.25, SNA, DECNET), broadband connections (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet, Ethernet-over-SONET), wireless connections, or a combination of any or all of the above). Connections can be established using a variety of communication protocols (e.g., TCP / IP, IPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, IEEE 802.11, IEEE 802.1 1a, IEEE 802.1 1b, IEEE 802.11g, IEEE 802.11n, IEEE 802.11ac, IEEE 802.1 1ad, CDMA, GSM, WiMax and direct asynchronous connections).In one embodiment, the computer device 500 communicates with other computer devices 500' via any type and / or form of gateway or tunnel protocol, such as Secure Socket Layer (SSL) or Transport Layer Security (TLS). The network interface 518 can include a built-in network adapter, a network interface card, a PCMCIA network card, a network bus adapter, a wireless network adapter, a USB network adapter, a modem, or any other device suitable for connecting the computer device 500 to any type of network capable of communication and performing the operations described herein.

[0086] In some embodiments, the computer device 500 may include or be connected to one or more display devices 524a-524n. Therefore, each of the I / O devices 530a-530n and / or the I / O controller 523 may include any type and / or form of suitable hardware, software, or combination of hardware and software to support, enable, or provide the computer device 500 to connect to and use the display device(s) 524a-523n. For example, the computer device 500 may include any type and / or form of video adapter, video card, driver, and / or library to connect, communicate with, connect to, or otherwise use the display device(s) 524a-524n. In one embodiment, a video adapter may have multiple connectors for connecting to the display device(s) 524a-524n.In other embodiments, the computer device 500 may have multiple video adapters, each video adapter being connected to the display device(s) 524a-524n. In some embodiments, each section of the operating system of the computer device 500 may be configured to use multiple displays 524a-524n. Persons skilled in the art will recognize and appreciate the various ways and embodiments in which a computer device 500 may be configured to have one or more display devices 524a-524n.

[0087] In further embodiments, an I / O device 530 can be a bridge between the system bus 550 and an external communication bus, such as a USB bus, an Apple Desktop bus, an RS-232 serial connection, a SCSI bus, a FireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, a Gigabit Ethernet bus, an Asynchronous Transfer Mode bus, a FibreChannel bus, a Serial Attached Small Computer System Interface bus, a USB connection or an HDMI bus.

[0088] A computer device 500 of the in Fig. 5B and Fig.The type shown in Figure 5C can operate under the control of an operating system that manages task scheduling and access to system resources. Any operating system can run on the Computing Device 500, such as any version of Microsoft Windows, the various versions of Unix and Linux, any version of Mac OS for Macintosh computers, any embedded operating system, any real-time operating system, any open-source operating system, any proprietary operating system, any operating system for mobile computing devices, or any other operating system capable of running on the Computing Device and performing the operations described herein. Typical operating systems include, but are not limited to, Android, manufactured by Google Inc.; WINDOWS 7 and 8, manufactured by Microsoft Corporation, Redmond, Washington; MAC OS, manufactured by Apple Computer, Cupertino, California; WebOS, manufactured by Research In Motion (RIM); OS / 2, manufactured by International Business Machines, Armonk, New York; and Linux, a freely available operating system distributed by Caldera Corp., Salt Lake City, Utah, or any type and / or form of Unix operating system, among others.

[0089] The Computer System 500 can be any workstation, telephone, desktop computer, laptop or notebook computer, server, portable computer, mobile phone or other portable telecommunications device, media player, gaming system, mobile computing device, or any other type and / or form of computing, telecommunications, or media device capable of communication. The Computer System 500 has sufficient processing power and memory capacity to perform the operations described herein.

[0090] In some embodiments, the computer device 500 can have different processors, operating systems, and input devices that are compatible with the device. For example, in one embodiment, the computer device 500 is a smartphone, mobile device, tablet, or personal digital assistant. In other embodiments, the computer device 500 is an Android-based mobile device, an iPhone smartphone manufactured by Apple Computer, Cupertino, California, or a Blackberry or WebOS-based portable device or smartphone, such as those manufactured by Research In Motion Limited.Furthermore, the computer device 500 can be any workstation, desktop computer, laptop or notebook computer, server, portable computer, mobile phone, any other computer or any other form of computing or telecommunications device capable of communication and possessing sufficient processing power and memory capacity to perform the operations described herein.

[0091] Although the disclosure may refer to one or more “users”, such “users” may refer to user-associated devices or stations (STAs), for example, in accordance with the terms “user” and “multi-user” typically used in connection with a multi-user multiple input and multiple output or multi-user multiple-input and multiple-output (MU-MIMO) environment.

[0092] Although examples of the communication systems described above may include devices and access points (APs) operating according to an 802.11 standard, it is understood that embodiments of the described systems and methods may operate according to other standards and use wireless communication devices that differ from those configured as devices and APs. For example, multi-unit communication interfaces belonging to cellular networks, satellite communications, vehicle communication networks, and other non-802.11 wireless networks may utilize the systems and methods described herein to achieve improved overall capacity and / or link quality without deviating from the scope of the systems and methods described herein.

[0093] It should be noted that certain passages of this disclosure use terms such as "first" and "second" in connection with devices, mode of operation, transmission chains, antennas, etc., for the purpose of identification and mutual differentiation. These terms are not intended to relate units (e.g., a first device and a second device) only temporally or according to a sequence, although these units may have such a relationship in some cases. Nor do these terms limit the number of possible units (e.g., devices) that can operate within a system or environment.

[0094] It should be noted that the systems described above can provide multiple instances of any or all of these components, and that these components can be deployed either on a standalone machine or, in some embodiments, on multiple machines in a distributed system. Furthermore, the systems and methods described above can be provided as one or more computer-readable programs or executable instructions contained on or within one or more manufacturing articles. The manufacturing article can be a floppy disk, a hard disk, a CD-ROM, a flash memory card, a PROM, RAM, ROM, or magnetic tape. Generally, the computer-readable programs can be implemented in any programming language, such as LISP, PERL, C, C++, C#, PROLOG, or in any bytecode language, such as JAVA.The software programs or executable commands can be stored as object code on or in one or more manufactured articles. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 299658

[0001]

Claims

[1] Method which features: Receiving, by a device, an input signal containing data for amplification and retransmission, and interference from one or more additional devices; Modifying the input signal by the device by applying attenuation for each of one or more frequency sub-bands, wherein the attenuation is based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; and Retransmission of the modified input signal by the device. [2] Method according to claim 1, wherein the one or more additional devices comprise one or more downstream devices, and wherein the interference comprises interference of re-upstream transmissions of data from the one or more downstream devices through the device. [3] Method according to claim 1, wherein the one or more additional devices comprise one or more upstream devices, and wherein the interference comprises leakage of upstream transmissions from the one or more upstream devices into a downstream signal. [4] Method according to claim 1, wherein the application of attenuation to the input signal further comprises converting the input signal from a time domain to a frequency domain, multiplying each subband of the frequency domain signal by a weight, and converting the input signal from the frequency domain to the time domain. [5] The method of claim 4, which further comprises calculating a weight for each of the one or more frequency sub-bands proportional to a difference between the energy of the input signal and the energy of the reference signal for the corresponding frequency sub-band. [6] Method according to claim 1, wherein the application of attenuation to the input signal is carried out in response to the fact that the amount of energy of the input signal for one or more frequency sub-bands exceeds a corresponding threshold value. [7] Method according to claim 6, which further comprises determining each sub-band energy threshold for the one or more frequency sub-bands by the device based on the reference signal. [8] The method of claim 1, further comprising: Receiving the reference signal by the device; and The device measures the amount of energy of the reference signal for each of the one or more frequency sub-bands. [9] Method according to claim 8, wherein receiving the reference signal further comprises receiving the reference signal during a period in which one or more additional devices are not transmitting. [10] Circuit which features: an input configured to receive an input signal containing data for retransmission and interference from one or more additional devices; a first sub-circuit configured to determine an attenuation amount to be applied to each of one or more frequency sub-bands of the input signal, wherein the attenuation is based on a comparison of an energy quantity of the input signal with an energy quantity of a reference signal for the corresponding frequency sub-band; a second sub-circuit configured to apply the specified attenuation amount to each of the one or more frequency sub-bands; and an output configured to retransmit the attenuated input signal.