76results about How to "Increase coverage distance" patented technology

The invention discloses a control channel transmission method and device comprising: a base station indicates to a terminal whether a physical downlink control channel of the terminal adopts serial transmission, when the serial transmission is adopted, sends multiple physical downlink control channels to the terminal in continuous multiple sub-frames and completes one resource distribution to the terminal via the multiple physical downlink control channels. The control channel transmission method of the invention can make UE obtain time selectivity gain and coding combination gain by adopting the serial transmission, can improve flexible degree of PDCCH resource occupation and can raise the resource utilization rate to improve the covering distance of PDCCH in order to enhance receiving property of PDCCH.

The invention discloses a high-speed rail LTE-R locomotive integrated wireless communication device, which includes an integrated main control / interface unit, and the output end of the main control / interface unit is electrically connected with a power supply unit, a recording unit, and an LTE-R communication device. Module, GSM‑R communication module, 450MHz wireless communication module and satellite receiving module, the LTE‑R communication module, GSM‑R communication module, 450MHz wireless communication module and satellite receiving module are all electrically connected to the antenna feeder unit, the The output end of the main control / interface unit is also electrically connected to an MMI unit, and the MMI unit is electrically connected to a printing unit and a display unit. The invention adopts large-scale integrated circuit and embedded software processing technology to construct locomotive comprehensive wireless communication equipment, realizes the integration of three communication modes of LTE-R, GSM-R and 450MHz digital-analog compatibility, and meets the special needs of smooth transition of various communication modes of railways. Based on the aggregated bandwidth technology of LTE, the LTE‑R (TDD) wireless transmission channel is constructed in the 450MHz frequency band to extend the coverage distance of the base station.

The invention provides a self-powered multi-parameter water quality monitor based on an NB-IOT (Narrow Band Internet of Things). The self-powered multi-parameter water quality monitor comprises a master control chip, an NB-IOT communication module, a multi-parameter water quality detection module and a self-powered device used for providing a power supply, wherein the master control chip is respectively connected with the NB-IOT communication module and the multi-parameter water quality detection module; the master control chip outputs a parameter detection instruction to the multi-parameter water quality detection module according to an operation instruction which is received by the NB-IOT communication module and sent from cloud; a water quality result returned from the multi-parameter water quality detection module is processed and is uploaded to the cloud through the NB-IOT communication module.

The invention provides Beidou dual-mode terminal equipment based on a navigation ADS-B application. The Beidou dual-mode terminal equipment comprises a baseband processing unit, a digital-to-analog processing unit and an antenna unit. The key resides in that the baseband processing unit comprises an RNSS module and an RDSS module. The mode of combination of the RDSS module and the RNSS module is adopted, position information of an aircraft is measured by utilizing the RNSS module and then position reporting is performed to the air traffic control department by utilizing the inbound short message service of the RDSS module. The RDSS module adopts the basic principle of an integrated scheduling mechanism of multiple IC user cards and is divided into two modes of a static mode and a dynamic mode so that the use requirements of users under different scenes can be flexibly supported, the situation that the positioning data source of an ADS-B system uses the GPS for a long time can be solved, the Beidou resources of our country can be fully utilized and security and confidentiality can be enhanced.

The invention discloses an integrated mine communication system based on a code division multiple access (CDMA) technology. According to the system, signal transmission equipment is connected with a CDMA base station for realizing data exchange; a surface scheduling module, the signal transmission equipment, the CDMA base station and a mine near-end signal converter are arranged on the ground; the CDMA base station and the mine near-end signal converter are connected to realize signal conversion; the mine near-end signal converter is respectively connected with multiple underground communication modules through an optical fiber network; the multiple underground communication modules are respectively arranged in a corresponding mine laneway; and each underground communication module comprises at least one mine wireless signal converter used for signal conversion and an intrinsic safety type CDMA voice terminal which is connected with the mine wireless signal converter through a CDMA network. The system can support the voice, data, short message transmitting and scheduling and PTT functions, the network is difficultly offline in the mine laneway working environment, the interference resistance is high, the voice communication effect is good, the underground wireless coverage effect is good, the system can be independently operated, and group customer networking can be realized.

The invention discloses a method for covering a tunnel in a TDD system, which includes the steps: RRU multipath output signals are combined into a single signal; the signal formed through combination is used for covering the tunnel and is partially fed back to the RRU; and the RRU calibrates the multipath output signals according to the signals which are fed back. The method has the technical scheme that the signal used for covering the tunnel can be partially coupled and fed back to the RRU, thus the RRU can calibrate the phase positions of the output signals according to the phase jitters generated by the transmission and the combination of the signals so as to realize the purpose of increasing the output power of the actual downlink signals and to increase the actual covering distance.The invention also provides equipment and a system which are used for covering the tunnel in the TDD system.

The invention belongs to the technical field of high-temperature component cooling of an air turbine, in particular to an air film hole based on secondary flows of a bent passage, which comprises two parts: a bent passage section and a straight passage section, wherein the bent passage section is a circular arc and is formed by bending an air film hole inlet in the air flow incoming direction. Because of the bent passage of the air film hole, on one hand, cooling air flows generate secondary flowing by an air film, formed passage vortexes are bent through the transverse pushing of high-temperature air flows after leaving the air film hole, the rotation direction opposite to kidney-shaped vortexes is realized, the development of the kidney-shaped vortexes can be inhibited after the interaction, the strength of the kidney-shaped vortexes is weakened, the attaching capability of the air film to the wall surface is improved, and the air film cooling efficiency is improved. On the other hand, because of the existence of the passage vortexes, the cooling air flows have higher expansion speed at the outlet part of the air film hole, and the coverage width of the air film can be increased.

The invention discloses a microwave remote wireless covering system and method. In which, the system comprises: a microwave accessing unit for receiving a radio-frequency signal from base station, converting into microwave signal, sending out through a microwave transmission unit, receiving the microwave signal from the microwave transmission unit, converting into radio-frequency signal and transmitting to the base station; a microwave transmission unit for performing microwave signal space transmission; and a microwave remote unit for receiving the microwave signal from microwave transmission unit, converting into radio-frequency signal, sending out to performing area covering, receiving radio-frequency signal from mobile station, converting into microwave signal and sending out through the microwave transmission unit; The microwave remote wireless covering system in the invention adopts microwave as transmission medium, can effectively reduce equipment cost, reduce engineering construction complexity, and greatly increase repeater networking flexibility and communication reliability; At the same time, the invention can effectively extend base station covering distance while guarantees that the normal work of the base station is not influenced.

The invention discloses a multi-beam selection intelligent antenna communication system which comprises an antenna control system and an antenna array. The antenna control system comprises a field programmable gate array (FPGA) logic control module, a wireless transceiver, a digital-to-analog conversion module, a phase shifter and a central processing unit (CPU). Radio frequency (RF) signals of the wireless transceiver reach the antenna array through the phase shifter. Two-path R / T control signals of the CPU and the wireless transceiver generate 16-path R / T signals through the FPGA logic control module, so as to control the receiving / transmission of the antenna array under the matching of the digital-to-analog conversion module. The phase shifter is a 360-degree continuous phase shifter formed by a circulator and at least one variode. The FPGA logic control module controls the digital-to-analog conversion module to generate an analog voltage to control a bias voltage of the variode, so as to change capacitance of the variode and achieve the objective of changing a radio frequency phase.

The invention relates to a WIA-PA based wireless gateway which comprises a power supply module, a digital filter and a gateway core board, wherein the digital filter and the network core board are connected with the power supply module, and the digital filter which is connected with an antenna is connected with the gateway core board. A communication method of the WIA-PA based wireless gateway comprises the steps that when data is received, the network core board sends a command to the digital filter via a serial port, the digital filter configures a reception channel according to the command and receives an RF signal via the antenna, the RF signal is filtered and then stored in a FLASH via a modem and converted into data of TCP / IP protocols via a CPU, and the data is transmitted via a network port; and when data is sent, the network core board modulates a digital signal into the RF signal and transmits the RF signal to the digital filter, an emission link in a narrowband filtering and amplification unit is powered on via a trigger signal of the modem, and the data is sent via the antenna. According to the WIA-PA based wireless gateway and the communication method thereof, interference signals in the 2.4GHz free frequency range as WLAN can be effectively filtered, the data reception sensitivity is improved, and the transmission distance is increased.

The embodiment of the invention provides a method, a device and equipment for optimizing the coverage area of a base station, and a medium. The method for optimizing the coverage area of the base station comprises the following steps: acquiring coverage parameters; the coverage parameters comprise an antenna model, a weight type and a frequency band; determining an antenna reference weight parameter according to the antenna model and the weight type; the antenna reference weight parameter comprises a reference amplitude and a reference phase; determining a corresponding adjustment table according to the frequency band; the adjustment table comprises an amplitude range and a phase range; respectively matching an amplitude adjustment factor corresponding to the horizontal half-power angle ofthe current antenna and a phase adjustment factor corresponding to the downward inclination angle of the current antenna; and determining the amplitude of the optimal antenna weight according to theamplitude adjustment factor, the reference amplitude and the amplitude range, and determining the phase of the optimal antenna weight according to the phase adjustment factor, the reference phase andthe phase range. The embodiments of the present invention are used for optimizing the coverage capability of a base station by adjusting antenna parameters.

This invention relates to a method for enlarging cover distance of base stations in a TDD radio communication system including: a time-sequence control module advances T1 the closing time of a transmitter or postpones T2 of the opening time of a receiver or their combination when keeping unchange of the time-sequence period of a TDD radio communication system to increase T1 or T2 or their combination corresponding to the protection time slot between up and down in the time-sequence period, which only needs to amend the distribution mode of time-sequence of a base station without considering a distance mode or amending process software of terminals.

The invention relates to a dipole antenna comprising the following units: a first radiator with the length equal to 1 / 4 wavelength of a corresponding preset frequency; a second radiator with the length equal to 1 / 4 wavelength of a corresponding preset frequency, wherein the second radiator and the first radiator form a first sub dipole antenna; a third radiator with the length equal to 1 / 2 wavelength of a corresponding preset frequency, wherein the first and third radiators are respectively arranged on two sides of the second radiator, the third and second radiators are connected in series to form a second sub dipole antenna, and the signal phases transmitted by the third and second radiators are stacked in the same direction. The first and second radiators form the first sub dipole antenna; the third radiator and the second radiator are connected in series, and signal phases transmitted by the two radiators are stacked in the same direction, thus increasing the signal intensity without being mutually cancelled, and forming a half-wavelength dipole antenna; two dipole antennas are stacked, so the antenna gain is obvious, thus enhancing the coverage distances.

The invention discloses a directional pattern reconfigurable antenna, a directional pattern reconfigurable method and a wireless terminal device. The directional pattern reconfigurable antenna includes a PCB and an array antenna arranged on the PCB. The array antenna is formed by multiple antenna subunits, and each subunit is connected to a radio frequency switching circuit via radio frequency signal sub-links. The radio frequency switching circuit is connected to a radio frequency processing unit, and the radio frequency switching circuit is used for controlling gating or closing of each antenna subunit according to switch gating control signals transmitted by the radio frequency processing unit so that the array antenna operates in a specific working mode. The invention has the followingadvantages: dynamical adjusting of a wireless coverage area can be realized, coverage distances can be increased, the received signal strength at user terminals can be enhanced, the communication quality can be improved, etc.

The present invention discloses a mobile station, a differential correction data transmission method, a terminal device, and a storage medium. A mobile station and a reference station is involved in the present invention; the mobile station comprises a first mobile station and a second mobile station; and a distance between the first mobile station and the reference station is less than the distance between the second mobile station and the reference station. The method comprises the following steps that: communication is established between the first mobile station and the reference station,and the reference station broadcasts differential correction data to the first mobile station; a radio module in the first mobile station forwards the differential correction data to a positioning module and an MPU processor; the MPU processor parses the differential correction data until a specified character is parsed to, so that the differential correction data corresponding to the specified character is saved to a transmission buffer; and the differential correction data of the transmission buffer is transmitted to the radio module, and the radio module transmits the differential correction data to the second mobile station to complete the transmission of the differential correction data. According to the technical scheme of the present invention, multiple mobile stations in the working range can be used to perform data transmission, so that the equipment cost can be reduced, and the efficiency can be improved.

The invention relates to a radio frequency system and communication equipment. The radio frequency system comprises a radio frequency transceiver, a first transceiving circuit, a second transceiving circuit and a diversity receiving circuit, wherein the first transceiving circuit and the diversity receiving circuit are configured to be connected with a first antenna and a second antenna in a switchable mode; the second transceiving circuit is configured to be connected with a third antenna; the diversity receiving circuit is configured to be connected with a fourth antenna; the first transceiving circuit supports emission and main set receiving of low-frequency signals; the second transceiving circuit supports emission and main set MIMO receiving of the low-frequency signals; and the diversity receiving circuit supports diversity receiving and diversity MIMO receiving of the low-frequency signals. Therefore, the radio frequency system can support double-path emission and a 4 * 4 MIMO function of the low-frequency signals; and when the radio frequency system is located in weak signal environments such as an edge of a community, a deep position of a building and an elevator, compared with a radio frequency system which can only support 2 * 2 MIMO receiving of the low-frequency signals in a related technology, the radio frequency system can double diversity gains, can double a coverage distance, and can greatly improve the receiving performance.

The invention relates to the field of bracelets and particularly relates to an intelligent anti-dismantle bracelet. The intelligent anti-dismantle bracelet comprises an alarming circuit, a waterproofcentral shell, a first wrist strap, a second wrist strap, an inserting buckle seat and an inserting buckle head, wherein the inserting buckle seat is connected at the tail end of the first wrist strap; the inserting buckle head is connected at the tail end of the second wrist strap; the alarming circuit comprises a first alarming line arranged in the first wrist strap, a second alarming line arranged in the second wrist strap, and an alarming circuit board arranged in the waterproof central shell and capable of controlling sending of an alarming signal; a metal wiring needle is arranged in theinserting buckle seat; a metal wiring hole is buried in the inserting buckle head; when the inserting buckle head is inserted into the inserting buckle seat, the metal wiring needle in the insertingbuckle seat is inserted into the metal wiring hole in the inserting buckle head; the first alarming line, the metal wiring needle, the metal wiring hole, the second alarming line and the alarming circuit board are connected in sequence to form a closed circuit. The intelligent anti-dismantle bracelet has the beneficial effects that after the intelligent anti-dismantle bracelet is worn for the first time, when any part on the intelligent anti-dismantle bracelet is broken, the anti-dismantle alarming circuit board in the intelligent anti-dismantle bracelet can be triggered to send the alarming signal.

The invention provides an information sending method and a terminal. The method comprises the following steps: determining a first sending resource for scheduling SA signaling and a second sending resource for data DATA in to-be-sent information, wherein the frequency band where the first sending resource is located is lower than or equal to the frequency band where the second sending resource islocated; and sending the to-be-sent information according to the first sending resource and the second sending resource. The method can solve the problems that in a V2X communication protocol in the prior art, SA and data are usually sent on one frequency band, the bandwidth is insufficient when low-frequency-band frequency domain resources are adopted, the coverage performance of high-frequency-band frequency domain resources is limited, and the high data transmission rate and the high coverage range and coverage distance of SA cannot be guaranteed at the same time.

The invention relates to a frequency selection device based on the WIA-PA protocols. The frequency selection device comprises a double-path phased-locked loop unit, an MCU and an RF narrowband filtering and amplification unit in sequential connection, the double-path phased-locked loop unit is connected with the RF narrowband filtering and amplification unit, and the RF narrowband filtering and amplification unit is also connected with an antenna and a modem. The frequency selection method comprises that when the MCU receives a switching command from a host computer, and the double-path phased-locked loop unit is configured to output first local oscillation and second local oscillation; after the model emits a reception trigger signal, first and second RF switches are switched to a reception link, and the reception link is powered on; and the RF narrowband filtering and amplification unit carries out low-noise amplification on a received RF signal, primary frequency mixing is carried out on the RF signal to generate an intermediate-frequency signal, the intermediate-frequency signal is filtered and amplified, secondary frequency mixing is carried out on the filtered and amplified intermediate-frequency signal so that the intermediate-frequency signal is recovered to an RF signal, and the recovered RF signal is amplified and then output by the switch RF switch. Interference of WLAN signals can be effectively filtered by increasing intermediate-frequency filtering in the reception link, the device reception sensitivity is improved, and the transmission distance is increased.

The invention discloses a method used for covering tunnels in a TDD system, comprising the steps as follows: a plurality of signals output by a remote radio frequency unit RRU are calibrated; two signals are selected out of a plurality of calibrated signals; the two signals are respectively used for covering tunnels. Two or more signals are used for covering tunnels, therefore, the emission power of the downlink signal can be greatly improved, the receiving gain of the uplink signal can be greatly improved, thus improving the practical coverage distance and meeting the coverage requirement better. The invention also provides equipment which is used for covering the tunnels in the TDD system, and a system which is used for covering the tunnels in the TDD system.

The invention relates to a mining 5G base station radio frequency energy loss optimization method and device. The optimization method comprises the following steps: selecting a coaxial cable model, and obtaining an attenuation coefficient and a diameter ratio parameter; determining the geometrical relationship between the length and the bending angle of the coaxial cable after the coaxial cable is installed and bent according to the roadway condition; and determining the bending angle and length when the attenuation is weakest based on the relationship between the mismatch coefficient and the angle, wherein the geometric relationship between the mounting of the mining 5G communication antenna and the base station in the roadway and the coaxial cable for realizing the connection is an isosceles triangle. The length of two equal sides of the isosceles triangle is half of the length of the coaxial cable, and the vertex angle of the isosceles triangle is the bending angle of the coaxial cable. Therefore, the emission efficiency of the radio frequency energy of the 5G base station can be improved, the coverage distance of the 5G base station can be improved, the layout number of the 5G base station can be reduced, and the construction cost can be reduced.

An actuator having a simple configuration requiring no high dimensional accuracy, high in positioning accuracy and low in cost, and a head-positioning mechanism using the actuator are disclosed. An actuator according to a first application comprises a shear-type piezoelectric element of predetermined thickness and an opposed electrode formed on two electrodes in spaced relationship on a base member. The opposed electrode is displaced in accordance with the direction of polarization of the shear-type piezoelectric element upon applying a voltage between the two electrodes. The opposed electrode thus constitutes an operating section of the actuator. An actuator according to a second application comprises a movable member arranged on a drive member including a shear-type piezoelectric element on a base member. The drive member includes a plurality of layers of piezoelectric elements polarized in alternately opposite directions perpendicular to the thickness of the devices. A plurality of conductive layers are formed adjacently to the respective layers of the devices to permit voltage application thereto. The movable member can be driven in parallel to the base member upon application of a voltage between the conductive layers. Any one of these actuators can be incorporated as a part of the head actuator to constitute a head-positioning mechanism capable of displacing the head by a minuscule distance independently of the operation of the head actuator.

The present invention provides a captive balloon communication system, the communication system comprises a ground support system, an RRU and a BBU; the RRU is disposed on a balloon, the BBU is disposed on the ground and the RRU forms a split base station, or the BBU is disposed on the balloon and forms an integrated base station with the RRU, the ground support system and the balloon are connected by a cable, the cable is provided with an optical fiber, and signal output of the BBU is transmitted through the optical fiber, and the optical fiber transmits baseband IQ data and OAM signaling data of the BBU to the RRU. The captive balloon communication system allows increasing balloon height, so that coverage distance is greatly increased, and reduces an interference path of multipath interference. The captive balloon communication system can effectively reduce influence of the radius of curvature of the earth on communication. The low-band frequency allows the signal to be transmitted beyond line of sight transmission, and the signal will be as far as 120km to 300km.

The invention relates to a radio frequency system and communication equipment, the radio frequency system comprises a radio frequency transceiver and a radio frequency transmit-receive circuit, the radio frequency transmit-receive circuit is connected with the radio frequency transceiver, the radio frequency transmit-receive circuit is configured with a first receiving path, a second receiving path, a third receiving path and a fourth receiving path, the first receiving path is connected with the second receiving path, and the third receiving path is connected with the fourth receiving path. The main set is configured to support main set receiving of low-frequency signals; the second receiving path is configured to be used for diversity reception of the low-frequency signals; the third receiving path is configured to be used for supporting MIMO receiving of the low-frequency signal; and the fourth receiving path is configured to be used for supporting MIMO receiving of the low-frequency signals, and can realize a 4 * 4 MIMO receiving function of the low-frequency signals so as to improve the receiving performance of the low-frequency signals.

The invention discloses a cloud relay communication system comprising at least one cloud relay platform lapped on a high altitude operating platform and a remote ground platform connected with the cloud relay platform; the remote ground platform comprises a first accessing / forwarding antenna, at least one frequency shift channel, an uplink merging module, a downlink shunting module, an uplink relay power amplifier module, a downlink relay low noise amplifier module, a first duplex module and a directional relay antenna, the first accessing / forwarding antenna, the frequency shift channel, the uplink merging module, the uplink relay power amplifier module, the first duplex module, the downlink relay low noise amplifier module and the downlink shunting module are connected in sequence, and the downlink shunting module communicates with the cloud relay platform through the frequency shift channel and the first accessing / forwarding antenna; and the directional relay antenna is connected with the first duplex module.

The invention belongs to the technical field of sensing, and discloses a culture fishery distributed water quality remote monitoring system and a monitoring method; the culture fishery distributed water quality remote monitoring system is composed of a water quality monitoring node, a network controller and an Internet of Things monitoring platform; wherein the water quality monitoring node is used for monitoring water quality through sensors, controlling on and off of aerators according to numerical values measured by the sensors, and sending collected data and an actuator state to the network controller through an LoRa communication module; the network controller is used for packaging all node data and then sending the packaged node data to the Internet of Things monitoring platform; and the Internet of Things monitoring platform is used for looking up the historical data of the sensors and remotely controlling the working state of each aerator of each node. The invention provides a communication scheme which can realize long distance, long battery life, simple installation, low cost, strong expansibility and secure encryption, and the system can be operated in global free frequency bands at present.

The invention discloses an uplink scheduling correction method based on an LTE system, and the method comprises the steps: calculating a scaling factor alpha according to the relation of an SINR (signal to interference plus noise ratio), a spectrum utilization ratio, a PHR, and a number of RBs of a scheduled PUSCH at the moments t1+t2 and t1+k; calculating the number (shown in the description) ofschedulable data channels RB at the moment t1+t2 according to the scaling factor alpha and the number (shown in the description) of schedulable data channels RB. The method reduces the number of uplink schedulable RBs on the basis of external annular link adaption when a mobile terminal moves an edge of a cell and the MCS is lower than a preset reference threshold MCSthreshold when a base stationside performs the scheduling of a terminal side PUSCH. Therefore, the method can improve the transmission energy on each RB when the terminal side performs the data transmission on a PUSCH, thereby improving the decoding capability of the PUSCH. Through this strategy, the coverage distance of the base station can be increased. In the field of private network communication, the method is applied tothe application field with the higher requirement for the coverage distance of the base station, and is higher in practical value.

The invention relates to a polarization array omnidirectional antenna of the PHS's base stations and mainly solves the problems of poor signal and small percentage of coverage of the tri-sector polarization diversity omnidirectional antenna in the PHS's base stations. We arrange the three minus or plus 45 degrees dual-polarization platy directional antennas with three 0 degree / 90 degrees dual-polarization platy directional antennas interlacedly on the baseline of a hexagon to form the hexad-sector twelve-array minus or plus 45 degrees and 0 degree / 90 degrees qua-polarization diversity antenna structure and carry out the threeway power synthesis to the directional antenna with same degree. The terminals of the hexad-sector antenna export four cable wires of +45 degree, -45 degrees, 0 degree and 90 degrees and connect with the base station to realize receiving and sending out the signal with different polarization methods. The antenna has an omnidirectional radiation directional diagram in the horizontal plane. Compared with the common level omnidirectional antenna, the gain of every polarization terminal is more than 12.5dB, the isolation between any two terminals is less than -25dB and it improves the coverage of the omnidirectional base stations greatly and increases the covering distance of the base stations.

The invention discloses an intelligent micro socket having a trapezoid structure. The intelligent micro socket comprises a top cover and a pedestal. Three-jack units, two-jack units and USB ports are formed in the top cover; and the top cover is installed at the pedestal at a 18.5-degree angle between the top cover and the horizontal plane. A 70-degree angle is formed between each of the front end surface and the rear end surface and the horizontal plane of the pedestal; the pedestal is provided with a touch type display screen and a power cord; the power cord is connected with the center of the rear end surface of the pedestal. The pedestal includes a housing, a single-chip microcomputer module, a wireless module and a circuit switch module; the housing is made of a flame-retardant PC material; the single-chip microcomputer module is connected with the wireless module, the circuit switch module, the a touch type display screen, and power cord. The wireless module is a wifi module; and the circuit switch module is provided with a relay. The intelligent micro socket has a novel and beautiful appearance and has functions of remote control, wifi relay and timing operation.