Abstract: A method for increasing coverage in a wireless communication system is described. The method comprises, at the network element: transmitting a first portion of subframes comprising a number of resource blocks to a first wireless communication unit in a first mode of operation, wherein the number of resource blocks are transmitted at a first power level per resource block; and transmitting, a second portion of subframes to a second wireless communication unit in a second mode of operation at a second power level, wherein the second portion of subframes comprise a lower number of resource blocks than the first portion of subframes and the lower number of resource blocks is transmitted at a second power level per resource block that is higher than the first power level per resource block.

Abstract: Example implementations are directed to systems and methods based on physical broadcast channel (PBCH) muting are utilized to avoid frequent cell selection/reselection and handover in a LTE-advanced heterogeneous network. In the example implementations, a pico eNB that is fully covered by a macro eNB or other pico eNBs transmits blank PBCH such that it is inaccessible to the UEs who perform cell selection/reselection. Furthermore, a macro eNB may handover a UE to the inaccessible pico eNB by signalling the necessary information to the UE to detect the inaccessible pico eNB. Frequent cell selection/reselection and handover may therefore be avoided in a dense deployment situation.

Abstract: Digital signal processing microphone occlusion detection is described that can be used with a noise suppression system that uses two types of noise estimators, including a more aggressive one based on two audio signals (such as for non-stationary noises) and a less aggressive one based on one audio signal (such as for stationary noises). Decisions are made on how to select or combine the outputs of the noise estimators into a usable noise estimate, based on an occlusion function. The occlusion detection may alternatively be used to trigger an alert to users of multi-microphone audio processing systems, such as smart phones, headsets, laptops and tablet computers. Other embodiments are also described and claimed.

Abstract: Methods and apparatus for interference coordination to improve transmission and reception performance within wireless networks. In one exemplary embodiment, a wireless transmitter transmits multiple transmissions over a determined time. The receiver receives the multiple transmissions and attempts to recover the transmitted signal. Because, the fading channel varies over time for each transmitter-receiver, by combining the received signals over multiple iterations, the signal of interest will be magnified, whereas interference effects will be suppressed.

Abstract: Methods and apparatus are provided for mitigating interference between spectrally distinct wireless communication networks employing co-located, collaborating radios. A first base station is in a first network and communicates with a first radio within a first frequency range, and a second base station is in a second network and communicates with a second radio in a second frequency range. The first and second radios are geographically co-located, for example, within a public safety vehicle. The first radio determines a maximum level of interference it will accept based on current operational parameters, and communicates a corresponding threshold value to the second radio through a data link. The second radio sends a request to its base station to employ interim scheduling constraints governing uplink transmissions from the second radio, to thereby limit out of band emissions received by the first radio to a range that is less than the threshold interference level.

Abstract: There is provided a communication control apparatus including a parameter acquisition unit that acquires parameters to calculate coverage of secondary systems from a secondary usage node operating the secondary systems on a frequency channel allocated to a primary system, a calculation unit that calculates the coverage of the secondary systems using the parameters acquired by the parameter acquisition unit, and an interference control unit that notifies a detection node that detects neighboring secondary systems of the secondary systems, of coverage information representing the coverage of the secondary systems calculated by the calculation unit.

Abstract: A communication device is described comprising a receiver configured to receive a radio signal from another communication device via a communication channel; a detector configured to detect the presence of an impairment of the communication channel; a determiner configured to determine a type of the impairment of the communication channel; and a transmitter configured to transmit an indication of the type of the impairment of the communication channel to the other communication device.

Abstract: Method for mitigating interference is established by means of a local wireless communication (204, 206) between a first portable communication device (PCD) (102, 301) and a second PCD (104, 302). The first and second PCD (301, 302) respectively communicate with first wireless network (110, 306, 310) and second wireless network (112, 308, 312) having different wireless air interface protocols. The local wireless communication link (107) is used to share (208) information (109, 111) concerning one or both of the first and second PCD. The information is then used to determine a communication priority (210) as between the first and second PCD with respect to at least one communication mode. The information is also used to selectively establish (212) an interference mitigation policy (304) to provide assured communications for the PCD with priority. The interference mitigation policy is executed (214) in the first and second PCD to cooperatively provide assured communication for the PCD with priority.

Abstract: The present invention relates to a method including aligning a boundary of a downlink subframe from the first base station to a first user equipment with a boundary of a downlink subframe from a second base station to a second user equipment; acquiring timing advance information indicating a time by which a boundary of an uplink subframe from the first user equipment to the first base station advances compared to the aligned boundary of the downlink subframe; and notifying the first user equipment of a time point at which an uplink subframe is transmitted from the first user equipment to the first base station based on the acquired timing advance information, wherein the boundary of the uplink subframe from the notified first user equipment to the first base station is aligned with a boundary of an uplink subframe from the second user equipment to the second base station.

Abstract: A system and methods for cancelling transmission leakage signals in a wide bandwidth Distributed Antenna System (“DAS”) having remote units is disclosed. An internal cancellation circuit within the remote unit is employed to reduce the transmitted leakage signals by generating a cancellation signal. This cancellation signal is added to the received signal to cancel the transmission leakage signal in the receiving signal path. A pilot signal generation circuit is employed to optimize the cancellation circuit operating parameters. The frequency of the pilot signal is swept over a range to determine the pilot frequency having the highest electromagnetic coupling. The amplitude and phase of the cancellation signal is then optimized to minimize the level of transmission leakage in the receiving transmission path.

Abstract: A method for mitigating a multi-path-induced error in a global navigation satellite system comprises, for a respective measurement epoch, obtaining respective representations of a composite signal including a plurality of value-pairs of the composite signal. The method further comprises, with respect to the measurement epoch: obtaining a plurality of coefficients for a set of linear equations based on the plurality of value-pairs of the composite signal; iteratively obtaining solutions for the set of linear equations, thereby solving for a code tracking timing offset, a time delay of a multi-path signal of the composite signal relative to its direct-path signal, and orthogonal representations of the multi-path signal; determining a phase error between the composite signal and the direct-path signal, due to the time delay, in accordance with the orthogonal representations of the multi-path signal; and correcting for the code tracking timing offset and the phase error.

Abstract: Data is synchronized between a mobile device and a computing device over a wireless link. Synchronization operations are scheduled according to a synchronization schedule that is based on a current time of day. In one embodiment, the day can be divided into different time periods by the user. The user can also specify the frequency with which synchronization operations are to be performed during each specified period.

Abstract: To cancel interference from the other cells and improve throughput characteristics without needing complicated processing, provided are a reception section that receives a reception signal including signal components from a plurality of base station apparatuses (BSs), and a signal detection and channel estimation section (61) that performs signal detection and channel estimation processing based on a factor graph on the reception signal, where the signal detection and channel estimation section (61) estimates interfering components from base station apparatuses of the other cells except a desired base station apparatus included in the reception signal at a symbol level, and reuses the interfering components in the signal detection and channel estimation processing based on the factor graph.

Abstract: To schedule uplink transmission time slots for a collection of mobile communication devices, a set of base station target interference patterns is associated with base stations. A time slot target interference pattern is assigned for each time slot and it repeats after several time slots. The time slot target interference pattern in a given time slot specifies the interference allowed by each time slot to a given base station by any single mobile. A priority index may be determined for each time slot for each mobile associated with the particular base station. The priority index may be based, in part, on a determined correlation between the time-slot target interference patterns and a potential interference profile of a mobile to which a time slot is to be allocated. A mobile's throughput requirement, the throughput already received over a specified past duration, the system fairness requirement, as well as the amount of data available for transmission are also used for evaluating the priority index.

Abstract: The concepts relate to radio channel utilization and more specifically to determining whether individual radio channels are available for use. One example can cause multiple sensing devices in a region to sense radio channels. The example can obtain signal information sensed by the multiple sensing devices in relation to an individual radio channel. The example can collectively analyze the signal information from the multiple sensing devices to determine whether the individual radio channel is being used for a licensed broadcast in the region.

Abstract: The present invention relates to a method for cancelling adjacent cells interference signal in a wireless communication system. In one embodiment this is accomplished by receiving desired user signal and cancel the channel effect using the desired users reference and or pilot signals, by a serving base station, identifying interference power by estimating the interferer power, determining if the interference is more than threshold, monitoring the interference and identify the interferer signal, re-generating the interference signal source and perform the channel estimate for the interferer, and canceling the interference by applying the interference pattern and the channel estimate to the desired user who's interference is more than threshold.

Abstract: An embodiment method for operating a controller of a communications system includes determining inter-cell interference coordination (ICIC) information for the communications system, automatically adjusting, by the controller without end-user input, ICIC parameters according to the ICIC information to improve an overall performance level of the communications system, and transmitting the ICIC operation parameters to network entities in the communications system.

Abstract: Methods and systems for identifying frequency band interference based on a mobile device activity record. The mobile device activity record may include a plurality of frequencies used by the mobile device and for each frequency in the plurality of frequencies a geographic location where the frequency was used. The mobile device activity record is received and compared to a spectrum license record that lists an assigned frequency band for an assigned geographic location. The assigned frequency band and assigned geographic location may be licensed to a frequency carrier. It is determined that that a frequency band interference has occurred based on identifying a frequency in the mobile device activity record when, according to the spectrum license record, the frequency is not licensed to a frequency carrier for the mobile device, in the geographic location where the frequency was used.

Abstract: Some example embodiments may be directed towards a method in a network node, which may be comprised in a Radio Network, for transmitting a combined wireless communication signal. The combined wireless communication signal may comprise a primary and a secondary signal component. The method may comprise transmitting to an user equipment the secondary signal component according to a secondary transmission scheme such that the secondary signal component at least partially overlaps with the primary signal component with respect to a signal domain. The method may also comprise simultaneously, suppressing at least one portion of the secondary signal component during a transmission of the primary signal component. Some example embodiments may be directed towards a method in an user equipment, which may be comprised in a Radio Network, for estimating the combined communication channel. The method may comprise receiving the combined wireless communication signal.

Abstract: In accordance with an example embodiment of the present invention, an apparatus, method and computer storage product are disclosed which compose a report at an apparatus having at least one network radio and at least one other radio, the report comprising in-device coexistence related information that combines information descriptive of potential and on-going interference to the at least one other radio as two orthogonal components comprised of power domain information and time domain information and transmit the report to a network station with which the apparatus communicates using the at least one network radio.

Abstract: A system and method to perform Full Duplex (FD) Space Division Duplex (SDD) communication using a Self-Interference Cancelling (SIC) precoder that applies different antenna phase shifts and amplitude scales to the transmitted signals to force them to be in the null space of the selected receive antennas. Thus, a wireless communication unit can place nulls at each of its receive antennas digitally at baseband for one or more frequency bands. The SIC precoder may be computed based on the self-interference channel from the transmit chain(s) to the receive chain(s). Different SIC precoders may be adaptively selected and stored digitally for different frequency bands. Subsequent single or multi-user precoder can be applied in concatenation with the SIC precoder to transmit signals to one or more users while receiving signals from one or more users simultaneously over the same frequency band.

Abstract: A scheme to reduce the problem of radio interference between wireless devices such as MTC devices in a multi-RAT scenario. Wireless devices are configured (S10) for interference reporting in accordance with their capabilities. Information is collected, not only on interference measurements reported by the wireless devices, but also on device signatures (S12) and transmission patterns (S14) for the purpose of attributing interference, suffered by a reporting device, to one or more offending devices (S16). One or more mitigation techniques is then applied to the offending device and/or the reporting device (S20-S24). The scheme provides an additional stability mechanism for existing interference mitigation and co-existence schemes by using device management and avoiding potential conflicts across diverse systems.

Abstract: The present invention discloses a link adaptation method, a base station and a terminal in a LTE system, wherein the method comprises: a terminal respectively calculating differences between a measured reference signal received power (RSRP) of a home service cell and the RSRPs of multiple adjacent cells; the terminal reporting the maximum difference in the differences to a base station; and the base station determining a modulation and coding scheme (MCS) for the terminal according to the maximum difference. The present invention does not introduce new overhead of the system, simplifies the flow of the AMC, and therefore improves the frequency spectrum efficiency of the system.

Abstract: A Communications base-station configured to operate as a hub in a wireless network and provide communication services to a set of remote customer devices using a wireless protocol is disclosed. The communications base-station includes an antenna array having a plurality of antennae arranged in a fashion as to enable the antenna array to transmit and receive wireless signals in both a substantially omnidirectional and non-omnidirectional pattern, a physical layer (PHY) device coupled to the antenna array and configured to transmit and receive wireless signals and a media access control (MAC) device coupled to the PHY device and configured to direct the antenna array to concurrently provide beamformed wireless signals to a first customer device and omnidirectional wireless signals to second customer device.

Abstract: A base station communicates with mobile terminals existing within a subordinate cell, and in addition executes control to reduce interference from mobile terminals existing within adjacent cells. The base station measures the total interference power received from mobile terminals in all adjacent cells, and if the total interference power is greater than a preset value, issues a request to the base stations of all adjacent cells to reduce interference. The base station which has received the interference reduction request discriminates mobile terminals which impart interference to the base station which is the source of the interference reduction request, and reduces interference by either temporarily lowering the uplink data transmission rate or temporarily halting uplink data transmission for such mobile terminals.

Abstract: The invention relates to a process for detection of a signal in a frequency sub-band of a frequency band of an acquired signal y(t), the process comprising: acquisition of the signal y(t) in a frequency band; frequential analysis of said acquired signal y(t) to obtain at least one frequential signal Y with NFFT frequential components; breakdown into M frequency sub-bands i of size N of the frequential signal Y, the size of each frequency sub-band being a function of the bandwidth of the signal to be detected; determination, in the frequential domain, for each frequency sub-band, of a criterion Ti, i=1, . . . , M as a function of the energy of the signal in the frequency sub-band i and of the coefficient two of the autocorrelation function of the signal in the frequency sub-band i; decision, as a function of the criterion Ti, to determine whether a signal is detected in the sub-band i.

Abstract: The present invention discloses a method and an apparatus for implementing network cognition. The method includes: determining a type of a received network task; according to the type of the received network task, selecting at least one cognitive capability identifier corresponding to the type of the network task; using network devices with the at least one cognitive capability identifier as alternative network devices; determining an alternative network device that is among the alternative network devices and has a cognitive capability that meets a condition for performing the network task is a target network device; and controlling the target network device to perform the network task.

Abstract: Methods and apparatuses are provided for determining one or more parameters of an access point that can be set or adjusted to mitigate interference to other access points. A rise-over-thermal (RoT) threshold can be set at an access point based on one or more parameters, such as pathloss measurements, location of the access point, etc., such that interference from devices communicating with the access point can be mitigated. In addition, a noise floor, RoT threshold, etc., can be adjusted based on determining a transmit power difference, out-of-cell interference, and/or similar measurements.

Abstract: In a method of controlling downlink transmitting power and antenna coverage of base stations in a communication system, the system comprising a plurality of base stations and a plurality of user equipment each associated with at least one of the plurality of base stations, providing (S10) interference and noise information for each of at least a subset of the plurality of user equipment. Subsequently, identifying (S20) at least one interfering base station for at least one user equipment of the subset, and jointly analyzing (S30) the provided interference and noise information for the subset together with the identified at least one interfering base station. Finally, jointly adapting (S40) a transmitting power level and/or an antenna beam of the at least one identified interfering base stations based on the analysis, to provide reduced power consumption and increased coverage in the communication system.

Abstract: Techniques are provided for detecting a coded signal in the presence of non-Gaussian interference. In an embodiment, a primary transmitter corresponds to a desired transmitter, and one or more secondary transmitters correspond to interfering transmitters. In an embodiment, received symbols, which include non-Gaussian interference and additive noise, are decoded to determine a set of message bits. In an embodiment, an estimate of the set of message bits may be determined using a minimum-distance detector or an optimal-ML detector, for example, depending on the signal-to-noise and/or signal-to-interference ratios at a receiver.

Abstract: In a system and method computerized devices are connected to each other over a wireless network and to a controller over an additional network. The devices perform antenna beam angle testing of the wireless network. The controller receives, over the additional network, transmitted and received test signal data acquired during such testing. Based on the test signal data, the controller calculates calibration data, which indicates, for each pair of devices, different path loss amounts associated with different transmitted test signal beam angles and a single transmitted test signal power level. The controller generates calibration matrices corresponding to each pair of devices using the calibration data; analyzes the matrices to determine, for each pair, an optimal antenna beam angle that results in the least amount of path loss; determines an optimal power level for the pair based on the path loss; and communicates the optimal specifications to the pair.

Abstract: Methods and arrangements in a telecommunication network for intercell interference coordination. The telecommunication network comprises a first base station, acting as serving base station for a mobile station, and a second base station. The method comprises determining that transmission interference to the mobile station is to be limited. The method also comprises triggering the mobile station to send a signal on a radio resource, which signal is to be received by the second base station, enabling the second base station to select a transmission parameter that limits interference for the mobile station.

Abstract: Methods and apparatus are described for interference cancellation of interference components of a time domain signal in the frequency domain. A communications device receives a time domain sequence and generates overlapping time domain segments from the time domain sequence. The overlapping time domain segments are then converted to the frequency domain to generate frequency domain representations of the overlapping time domain segments. The frequency domain representations are stored in a residual memory, and interference components are directly removed from the frequency domain representations stored in the residual memory in the frequency domain.

Abstract: An apparatus and method of allowing user equipment to transmit information directly with other user equipment, using a device-to-device mode is disclosed herein. A device-to-device blank subregion is defined where device-to-device information can be transmitted without interference from other user equipment. The device-to-device blank subregion may be set up such that it is only used in an exclusive mode if a device-to-device cluster is considered highly interfering. A device may join a device-to-device network through the use of a beacon transmission interval, a control transmission interval, and a data transmission interval.

Abstract: The present invention concerns a method for controlling the interferences generated by radio signals transferred by or to wireless telecommunication devices of a wireless cellular telecommunication network. The method comprises the steps of: forming at least one group of wireless telecommunication devices, allocating at least one identifier to each wireless telecommunication device of the group, the at least one identifier, said as group identifier, being allocated to each wireless telecommunication device of the group of wireless telecommunication devices, the group identifier being intended to be transferred by each wireless telecommunication device to mobile terminals in parallel with another identifier, allocating the same parameters for controlling the interferences generated by radio signals transferred to or by each wireless telecommunication device of the group.

Abstract: A method is provided to reduce inter-cell interference in mobile wireless systems, and particularly in TDD wireless systems. In an embodiment, a base station receives a pilot signal from at least one of the mobile terminals that it serves at a plurality of base station antennas, which include both main antennas and auxiliary antennas. In response, each of the base station antennas provides an output that is processed to obtain a set of precoding weights for a transmission from the main antennas. The processing includes nulling at least one interfering signal using the outputs from at least the auxiliary antennas.

Abstract: A first User Equipment (UE), a second UE, a first Radio Network Node (RNN), and methods therein for controlling interference between transmissions in a first system and transmissions in a second system. The first system comprises the first UE and the first RNN serving the first UE. The second system comprises the second UE and a second RNN serving the second UE. The first system has a first priority in a first part of a shared spectrum and the second system has a second priority in the first part of the shared spectrum, wherein the first priority is higher than the second priority. The method in the first UE comprises transmitting a signal to a second RNN that is to perform a downlink transmission to the second UE, which signal is configured to control the transmission of the second RNN.

Abstract: A method and an apparatus for uplink power control in a wireless communication system are provided. More specially, a method is provided in which a first base station in a wireless communication system periodically measures interference for a cell of a second base station neighboring the first base station, determines an average of the periodically measured interference, broadcasts the determined average of the periodically measured interference to mobile terminals located in a cell of the first base station, determines a weight for the determined average of the periodically measured interference, based on one of resource allocation information for the cell of the second base station and whether a specific message for interference regulation is received from the second base station, and transmits the determined weight to the mobile terminals.

Abstract: A radio communication device may include: a receiver configured to receive a first signal in a first shared radio communication channel of a first cell and configured to receive a second signal in a second shared radio communication channel of a second cell, wherein the first signal includes an information and the second signal includes the same information; and a determination circuit configured to determine the information based on the received first signal and the received second signal.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for measuring power levels of signals provided by a receiver configured to scan radio frequency signals over a wide frequency band, calculating an average power level from at least a portion of the measured power levels, determining a threshold, detecting interference in the wide frequency band based on the threshold, the average power level, or both, and causing a null that substantially suppresses the interference received by the receiver. Other embodiments are disclosed.

Abstract: This communication device for rail vehicle is of the type comprising a wireless communication stage to communicate with a control beacon on at least one communication spectrum band of a spectral range sub-divided into several predetermined channels.

Abstract: The present invention relates to a method for mitigating inter-cell interference in a multi-cell DAS. In one embodiment of the present invention, user equipment estimates an interfering antenna of an adjacent cell on the basis of RS pattern information of the adjacent cell, provided by a base station of a serving cell, or the base station provides the user equipment with information which specifies an interfering cell of the adjacent cell.

Abstract: Technology for spatial domain beamforming coordination at a low power node (LPN) in a heterogeneous network (HetNet) is disclosed. One method can include the LPN collecting spatial feedback information of macro node interference from a plurality of wireless devices in a LPN cell. The LPN can compile the spatial feedback information into a spatial feedback report. The LPN can send the spatial feedback report from the LPN to a macro node for calculating a beamforming vector to reduce the macro node interference for the plurality of wireless devices in the LPN cell.

Abstract: A radio communication system whereby a range is enabled and communication control and quality can be ideally maintained even if the communication distance changes. The transmitting apparatus has a transmitting unit that repeatedly transmits one data packet; a receiving unit that repeatedly receives a response packet; an integrating unit that integrates a repeatedly received response packet; and a determining unit that determines, by use of a result of the integration, whether the received response packet is correct. The receiving apparatus has a receiving unit that repeatedly receives a data packet; an integrating unit that integrates a repeatedly received data packet; a determining unit that determines, by use of a result of the integration, whether the received data packet is correct; and a transmitting unit that repeatedly transmits the response packet when determination is made that the received data packet is correct.

Abstract: The invention relates to a wireless home gateway apparatus and methods of wirelessly delivering audio and/or video programs between a home gateway and a client and mitigating interference thereon. Specifically, the present invention relates to transmitting an audio/video program on two white space channels and alternately stopping transmission on one of said channels to search for external transmissions on the white space channel. The present invention permits the wireless home gateway to continuously transmit an audio/video program to a client while periodically searching for transmitters on each of the white space channels.

Abstract: A method for partitioning a communications network includes selecting, by a controller, a starting communications controller for a first region in the communications network according to an interference level. The method also includes including, by the controller, a first neighboring communications controller in the first region if an average inter-cell interference level of the starting communications controller and the first neighboring communications controller exceeds a first threshold and closing the first region if the average inter-cell interference level of the starting communications controller and the first neighboring communications controller fails to exceed the first threshold. The method further includes storing information about the first region in a memory.

Abstract: A wireless receiving apparatus includes a spurious component extraction unit, and a spurious cancellation unit. The spurious component extraction unit is configured to cancel a desired wave with a multi-antenna configuration, and extract spurious components. The spurious cancellation unit is configured to cancel spurious in received signals by using the spurious components extracted. A first correlation unit in the spurious component extraction unit finds a correlation between an output of the spurious extraction unit and an output of the spurious cancellation unit.

Abstract: A machine-implemented system and method are described for removing interference between adjacent distributed-input-distributed-output (DIDO) clusters comprising. For example, a method according to one embodiment comprises: detecting signal strength at a first client from a main DIDO cluster; detecting interference signal strength at the first client from an interfering DIDO cluster; if the signal strength from the main DIDO cluster reaches a specified value relative to the value of the interference signal strength from the interfering DIDO cluster, then generating channel state information (CSI) defining channel state between one or more antennas of the first client and one or more antennas of the interfering DIDO cluster; transmitting the CSI from the first client to a base transceiver station (BTS) in the interfering DIDO cluster; and implementing DIDO precoding with inter-DIDO-cluster interference (IDCI) cancellation at the BTS in the interfering DIDO cluster to avoid RF interference at the first client.

Abstract: A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

Abstract: A wireless communication system according to an embodiment includes a first radio equipment that transmits first data using first radio waves, a data transmitter that transmits a second radio wave for causing a disturbance on the first radio wave according to second data, and a second radio equipment that modulates the first data transmitted from the first radio equipment, and modulates the second data transmitted from the data transmitter using a variation in a bit error rate of communication between the first radio equipment and the second radio equipment. The data transmitter includes an amplifier that amplifies a signal corresponding to the first radio wave received by a first antenna, and a feedback element that feedbacks a signal from an output node of the amplifier to an input node of the amplifier, and forms a feedback loop.