WO2016078324A1 - 下行导频抑制方法、装置及干扰机 - Google Patents

下行导频抑制方法、装置及干扰机 Download PDF

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Publication number
WO2016078324A1
WO2016078324A1 PCT/CN2015/077229 CN2015077229W WO2016078324A1 WO 2016078324 A1 WO2016078324 A1 WO 2016078324A1 CN 2015077229 W CN2015077229 W CN 2015077229W WO 2016078324 A1 WO2016078324 A1 WO 2016078324A1
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signal
air interface
interference
power
pilot
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PCT/CN2015/077229
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English (en)
French (fr)
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胡文彬
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中兴通讯股份有限公司
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information

Definitions

  • This paper relates to the field of communication technologies, and in particular, to a TD-SCDMA (TDS, TimeDivision-Synchronous Code Division Multiple Access) downlink pilot suppression method, device and jammer.
  • TDS TimeDivision-Synchronous Code Division Multiple Access
  • TD-SCDMA wireless networks are widely covered in China.
  • users in a certain area need to be prevented from accessing 3G networks.
  • cell search process of the mobile phone The process of booting a mobile phone and logging in to a suitable cell is defined as a cell search. After the mobile phone is turned on, the cell search process of TD-SCDMA can be roughly divided into the following steps:
  • the first step to find the location of the cell Dwpts is the basis for the cell search success.
  • the principle of suppressing the interference device of the mobile phone user accessing the base station is: synchronizing the wireless interference device to the macro base station cell in real time, and transmitting the interference code in the Dwpts position, so that the mobile phone user in the interference area cannot be synchronized to the TD- SCDMA network.
  • the process of synchronizing the jammer to the macro station cell is consistent with the first step of the cell phone cell search, that is, searching for the location of the Dwpts of the air interface.
  • the basic principle of sliding correlation is: using the relevant characteristics of the SYNC code, the 32 sets of SYNC_DL codes are respectively correlated with the received signal. When the maximum correlation value is found, the position of the SYNC_DL and the set of SYNC_DL codes are found.
  • the basic principle of the feature window method is to use the power shape of Dwpts to determine the approximate position of Dwpts.
  • the TD-SCDMA radio frame structure divides a 10 ms radio frame into two 5 ms sub-frames, each of which has 7 regular slots (including TS0, broadcast channel) and 3 special slots.
  • the three special time slots are a downlink pilot time slot DwPTS, a guard time slot GP, and an uplink pilot time slot UpPTS.
  • the physical sub-frame structure of the TDS is shown in Figure 1.
  • There is a guard interval around SYNC_DL There is a guard interval around SYNC_DL. During this period of protection, neither the base station nor the mobile terminal sends a signal, and SYNC_DL transmits at the full power level. Therefore, the power of the SYNC_DL itself is much larger than the power of the guard slots on both sides. Comparing the power of SYNC_DL with the power of the two GP slots, the approximate position of
  • the embodiments of the present invention provide a downlink pilot suppression method, apparatus, and jammer to solve the technical problem of how to effectively adapt to interference of a spontaneous interference signal and a complicated external environment, and stably lock a pilot signal of a cell.
  • an embodiment of the present invention provides a downlink pilot suppression method, including:
  • the step of searching for the air interface pilot signal, searching for the location of the cell DWPTS according to the air interface pilot signal, and based on the power feature window method includes:
  • the power feature matching curve is compared with the set power feature window. If it matches, it is determined that the location of the cell DWPTS is searched for, and the lock indication signal is output.
  • comparing the power feature matching curve with the set power feature window includes:
  • the power feature matching curve is compared with the set power feature window in combination with an anti-noise processing technique.
  • the step of sending an interference signal to the air interface at the location of the cell DWPTS based on the interference source and combining the automatic gain control technology includes:
  • the reverse The gain control module While transmitting the interference signal, continuously monitoring the lock indication signal, and when the lock indication signal is not detected, increasing a gain of the set reverse gain control module until the lock indication is normal, the reverse The gain control module is provided with an initial attenuation value.
  • the method further includes:
  • the regular time slot TS0 area sends an interference signal to the air interface; the transmission length of the interference signal at the location of the cell DWPTS is smaller than the transmission length of the air interface pilot signal.
  • the method further includes:
  • the received air interface pilot signal is filtered, low noise placed, gain adjusted, and/or down converted to an intermediate frequency signal.
  • the method further includes:
  • the embodiment of the present invention further provides a downlink pilot suppression apparatus, including:
  • a pilot search module configured to search for an air interface pilot signal, and search for a location of the cell DWPTS according to the air interface pilot signal and based on a power feature window method
  • Generating a module configured to generate an interference source when the location of the cell DWPTS is searched;
  • the sending module is configured to send an interference signal to the air interface at the location of the DWPTS of the cell based on the interference source and the automatic gain control technology, so that the interference signal is superimposed with the air interface pilot signal, and then the air interface is transmitted.
  • the pilot search module is configured to receive an air interface pilot signal sent by the cell, dynamically obtain a bottom noise power value of the air interface pilot signal, and detect an average power of the air interface pilot signal; Describe the bottom noise power value and the mean power level, and generate a power feature matching curve according to the comparison result; compare the power feature matching curve with the set power feature window, and if matched, determine the location of the searched cell DWPTS, and output the lock Indication signal.
  • the pilot search module is configured to compare the power feature matching curve with a set power feature window by:
  • the power feature matching curve is compared with the set power feature window in combination with the anti-noise processing technique.
  • the sending module is configured to continuously monitor the lock indication signal when transmitting the interference signal, and improve a gain of the set reverse gain control module when the lock indication signal is not detected
  • the reverse gain control module is set to have an initial attenuation value until the lock indication is monitored to be normal.
  • the sending module is further configured to send an interference signal to the air interface in the regular time slot TS0 area; the transmission length of the interference signal at the location of the cell DWPTS is smaller than the transmission length of the air interface pilot signal.
  • the pilot search module is further configured to filter, low noise, gain adjust, and/or downconvert the received air interface pilot signal to an intermediate frequency signal.
  • the sending module is further configured to upconvert the interference source to a radio frequency signal; and perform power amplification and filtering on the transmitted interference signal.
  • Embodiments of the present invention also provide a jammer, including the apparatus as described above.
  • Embodiments of the present invention also provide a computer storage medium, where the computer storage medium is stored There are computer executable instructions for performing the methods described above.
  • the downlink pilot suppression method and device and the jammer according to the embodiment of the present invention detect the air interface pilot signal based on the power feature window method, combine the dynamic gain control technology, and the anti-self-interference optimization, so that the interference function can effectively adapt to the spontaneous interference.
  • 1 is a schematic structural diagram of a TD-SCDMA subframe
  • FIG. 2 is a schematic flowchart of a downlink pilot suppression method according to an embodiment of the present invention
  • FIG. 3 is a schematic structural diagram of a jammer system designed according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of a power feature matching curve generated by an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of interference signal output of a jammer according to an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of functional modules of a downlink pilot suppression apparatus according to an embodiment of the present invention.
  • the air interface pilot signal is detected based on the power feature window method, combined with the dynamic gain control technology and the anti-self-interference optimization, so that the interference function can effectively adapt to the interference of the spontaneous interference signal and the complex external environment, and stably lock the cell.
  • the pilot signal effectively suppresses the access of the mobile phone user within the interference range to the TDS network.
  • an embodiment of the present invention provides a downlink pilot suppression method, including:
  • Step S101 Search for an air interface pilot signal, and search for a location of the cell DWPTS according to the air interface pilot signal according to the power feature window method;
  • the jammer design does not need to know the SYNC_DL code of the cell, use the sliding phase.
  • the off method will cause too much computation waste, and the correlator design is complex; and the related feature window method can not effectively adapt to the interference of spontaneous interference signals and complex external environment.
  • the embodiment of the invention designs a TD-SCDMA jammer adapted to indoor and outdoor environments, detects air interface pilot signals based on power feature window method, combines dynamic gain control technology, and anti-self-interference optimization, so that the jamming function can effectively adapt to spontaneous Interference signal interference and complex external environment, stably lock the pilot signal of the cell, effectively suppress the mobile phone users within the interference range from accessing the TDS network.
  • the jammer system designed in this embodiment is composed of an antenna (including a receiving antenna and a transmitting antenna), a filter, a power amplifier unit, a low noise amplifier unit, a gain adjusting unit, and a medium RF link unit.
  • the DWPTS pilot detection module and the interference source generation module are composed.
  • the receiving antenna is configured to receive an air interface pilot signal sent by the cell, and an omnidirectional antenna is used as the receiving antenna.
  • the transmit antenna is configured to transmit a pilot interferer to the air interface, and the directional antenna is used to transmit the interference signal to a fixed area.
  • the filter is set to filter out signals other than TD-SCDMA.
  • the power amplifier unit and the low noise amplifier unit are arranged to amplify the received signal and the transmitted signal.
  • the gain adjustment module of the transmission direction is set to implement power adjustment of the transmission signal and control the interference area range.
  • the reverse gain adjustment module is set to implement dynamic gain control for reverse reception, increasing the anti-jamming performance of the jammer.
  • the reverse received medium RF link unit is configured to downconvert the received RF signal to an intermediate frequency signal.
  • the medium-frequency link unit of the forward transmission is set to up-convert the interference source generated by the pilot interference source generating module to the radio frequency, and is amplified by the power amplifier and sent to the air interface.
  • the location of the DWPTS of the cell is searched based on the power feature window method, and the process is as follows:
  • the jammer receives the air interface pilot signal sent by the cell; dynamically acquires the bottom noise power value of the air interface pilot signal; and detects the average power of the air interface pilot signal.
  • the bottom noise power value and the average power level are compared, and a power feature matching curve is generated according to the comparison result.
  • the power feature matching curve is compared with the set power feature window. If it matches, it is determined that the location of the cell DWPTS is searched, and the lock indication signal is output.
  • the DWPTS pilot detection module performs a pilot search using a feature window method, and the bottom layer is implemented using an FPGA (Field Programmable Gate Array).
  • the SYNC_DL code has 64chip (1.28Mcps) for full power transmission, and 48chip and 96chip guard slots are not signaled before and after SYNC_DL.
  • the mean power in the protection time slot is the noise floor of the received signal, assuming that the signal greater than or equal to the noise floor A db is high (A can be set), and the signal below the noise floor Adb is low.
  • the power curve of the DWPTS position is 37.5us low, 50us high, and 75us low.
  • the pilot detection technique designed in this embodiment can be performed according to the following steps:
  • the time domain detection length of the bottom noise design in this embodiment is B, B ⁇ GP2/2.
  • the bottom noise value design M ms is updated once (M can be set), keeping the minimum value within M ms each time. Ensure that the interference function adapts to changes in the external environment and dynamically update the noise floor power value.
  • the mean power for obtaining the noise floor is defined as P1.
  • SYNC_DL is 50us long and has guard slots greater than 25us before and after. Therefore, in this design, the length of the power matching window is set to 100us. Since the detection length in step 2 is C, in the case where the particle size is C, 100us is divided into 100/C aliquots. Therefore, in step 2, C needs to be designed to be a common divisor of 100us, so that the number of high and low levels obtained in step 3 is exactly an integer. Through the above design, the high and low levels stored in the cache RAM should be 25/C low level, 50/C high level, and 25/C high level.
  • Step S102 When searching for the location of the cell DWPTS, generating an interference source
  • an interference source is generated in the FPGA according to the lock indication signal generated in step 5 of step S101.
  • the interference source is a random sequence, and the data source is modulated by the medium frequency to the application frequency of the TDS network.
  • the receiver described in the embodiments of the present invention supports the F-band (1880-1920 MHz) and the A-band (2015-2025 MHz).
  • Step S103 based on the interference source and combined with the automatic gain control technology, send an interference signal to the air interface at the location of the cell DWPTS, so that the interference signal is superimposed with the air interface pilot signal, and then perform air interface transmission.
  • the interference signal is superimposed on the air interface pilot signal and then transmitted outside the air interface, so that the interference of the interference signal can prevent the mobile terminal and the like from searching for the air interface pilot signal, that is, the mobile terminal and the like cannot find the base station.
  • the cell information is such that the base station cannot be accessed.
  • the interference sequence can only be transmitted at the downlink pilot position.
  • the interference signal of Figure 5 is designed, the interference signal is transmitted in the TS0 area, and the interference signal of less than 50us width is transmitted in the SYNC_DL position. Since the SYNC_DL time domain width of the air interface is larger than the interference signal, it does not cause a false positive when generating the power matching curve. Moreover, after the actual measurement, the interference effect is best when the interference signal is also transmitted in the TS0 area.
  • an interference signal is sent to the air interface at the location of the cell DWPTS.
  • the jammer searches for the pilot signal of the air interface base station and sends a high power interference signal to the air interface.
  • the transmitted interference signal is superimposed with the pilot signal of the base station.
  • the interference signal transmitted by itself is high, which may block the reverse link device of the interference machine.
  • the interference signal may affect the judgment of the interference signal to the air interface pilot signal.
  • This design uses dynamic gain control technology and designs a special output interference signal, which effectively reduces the effects of self-interference.
  • the reverse gain control module sets an initial attenuation value, and the system continuously monitors the lock indication signal of the pilot detection module.
  • the system increases the gain of the reverse gain control module. Until the monitoring of the lock indication is normal.
  • the noise floor of the jammer obtained according to the detection length of 20us during the initial search is -98dbm. Since the pilot signal of the air interface has a good signal-to-noise ratio with respect to the noise floor, it is assumed that the power of the pilot position reaches about -70 dBm. Setting the noise greater than the bottom noise of 6dm is a high-level signal, so that the pilot position will obtain the first 25us length low level, then 50us high level, then 25us low level power window. This feature matches the designed power feature window and outputs a lock indication signal indicating that the internal disturbance source generation module begins to generate an interference source.
  • the noise floor of the jammer changes rapidly.
  • the noise floor changes to -80dbm
  • the jammer can adapt to the environmental changes and ensure that the generated power window is not deformed. If it is a method of fixed detection threshold, if the detection threshold is designed below -80dbm, the power feature window cannot be obtained.
  • the jammer starts to transmit the interference signal according to the designed time domain characteristics, and the interference signal is amplified by the jammer to the antenna port output, and the output power reaches 45dbm.
  • the interference signal is designed to transmit the interference signal at the pilot position and the TS0 position.
  • the transmission length of the pilot position needs to be less than the 50us length of the pilot signal sent by the air interface.
  • the interference signal sent by the embodiment of the present invention is only 40 us, so that the interference signal is in the air interface. Within the frequency signal, when the air interface pilot signal is superimposed and entered into the RRU, the judgment of the power characteristic curve is not affected.
  • the 45dbm interference signal is transmitted at the same frequency as the received signal, which is transmitted out through the air interface coupling.
  • the received signal has an amplification function, so that the power to the intermediate frequency ADC port exceeds its saturated power.
  • the automatic gain adjustment technology designed by the embodiment of the invention can adjust the gain adjustment module of the interference link of the jammer in real time, and monitor the lock indication signal in real time. If the lock cannot be locked for a period of time, the attenuation amount of the signal is adjusted and re-detected until stable locking. . In addition, if the pilot signal has a more serious tailing, all power window detection methods will fail. At this time, the gain adjustment module automatically attenuates the input signal, and the tailing of the pilot signal can be reduced, thereby functioning as a signal shaping.
  • the algorithm part of the embodiment of the invention is implemented by using an FPGA (Field Programmable Gate Array), which has a fast running speed and can track and lock the air interface pilot signal in real time.
  • FPGA Field Programmable Gate Array
  • the logic resources used are small, only two DSP cores are needed, and a small amount of lookup table resources can be used to complete the operation, which saves system cost compared with a complicated filter designed.
  • the embodiment of the invention detects the air interface pilot signal based on the power feature window method, combines the dynamic gain control technology, and the anti-self-interference optimization, so that the interference function can effectively adapt to the interference of the spontaneous interference signal and the complex external environment, and the stable locked cell guide
  • the frequency signal effectively suppresses the access of the mobile phone user within the interference range to the TDS network.
  • the embodiment of the present invention provides a downlink pilot suppression apparatus, which is carried in a jammer.
  • the apparatus includes: a pilot search module 201, a generation module 202, and a sending module 203, where:
  • the pilot search module 201 is configured to search for an air interface pilot signal, and search for a location of the cell DWPTS according to the air interface pilot signal according to the air interface pilot method; the pilot search module 201 may be a DWPTS pilot as shown in FIG. Detection module
  • the generating module 202 is configured to generate an interference source when the location of the cell DWPTS is searched; the generating module 202 may be the interference source generating module shown in FIG. 3;
  • the sending module 203 is configured to send an interference signal to the air interface at the location of the cell DWPTS based on the interference source and in combination with the automatic gain control technology, so that the interference signal is superimposed with the air interface pilot signal, and then the air interface is transmitted.
  • the embodiment of the invention designs a TD-SCDMA jammer adapted to indoor and outdoor environments, detects air interface pilot signals based on power feature window method, combines dynamic gain control technology, and anti-self-interference optimization, so that the jamming function can effectively adapt to spontaneous Interference signal interference and complex external environment, stably lock the pilot signal of the cell, effectively suppress the mobile phone users within the interference range from accessing the TDS network.
  • the pilot search module is configured to receive an air interface pilot signal sent by the cell; dynamically obtain a bottom noise power value of the air interface pilot signal; and detect an average power of the air interface pilot signal; Describe the bottom noise power value and the mean power level, and generate a power feature matching curve according to the comparison result; compare the power feature matching curve with the set power feature window, and if matched, determine the location of the searched cell DWPTS, and output the lock Indication signal.
  • the pilot search module is configured to compare the power feature matching curve with a set power feature window by combining the power feature matching curve and the set with an anti-noise processing technique.
  • the power feature window is compared.
  • the sending module is configured to continuously monitor the lock indication signal when transmitting the interference signal, and improve a gain of the set reverse gain control module when the lock indication signal is not detected
  • the reverse gain control module is set to have an initial attenuation value until the lock indication is monitored to be normal.
  • the sending module is further configured to send an interference signal to the air interface in the normal time slot TS0 area; the transmission length of the interference signal at the location of the cell DWPTS is smaller than the transmission length of the air interface pilot signal.
  • the pilot search module is further configured to filter, low noise, gain adjust, and/or downconvert the received air interface pilot signal to an intermediate frequency signal.
  • the sending module is further configured to upconvert the interference source to a radio frequency signal; and perform power amplification and filtering on the transmitted interference signal.
  • the jammer system designed in this embodiment is composed of an antenna (including a receiving antenna and a transmitting antenna), a filter, a power amplifier unit, a low noise amplifier unit, a gain adjusting unit, and a medium RF link unit.
  • the DWPTS pilot detection module and the interference source generation module are composed.
  • the receiving antenna is configured to receive an air interface pilot signal sent by the cell, and an omnidirectional antenna is used as the receiving antenna.
  • the transmit antenna is configured to transmit a pilot interferer to the air interface, and the directional antenna is used to transmit the interference signal to a fixed area.
  • the filter is set to filter out signals other than TD-SCDMA.
  • the power amplifier unit and the low noise amplifier unit are arranged to amplify the received signal and the transmitted signal.
  • the gain adjustment module of the transmission direction is set to implement power adjustment of the transmission signal and control the interference area range.
  • the reverse gain adjustment module is set to implement dynamic gain control for reverse reception, increasing the anti-jamming performance of the jammer.
  • the reverse received medium RF link unit is configured to downconvert the received RF signal to an intermediate frequency signal.
  • the medium-frequency link unit of the forward transmission is set to up-convert the interference source generated by the pilot interference source generating module to the radio frequency, and is amplified by the power amplifier and sent to the air interface.
  • the location of the DWPTS of the cell is searched based on the power feature window method, and the process is as follows:
  • the jammer receives the air interface pilot signal sent by the cell; dynamically acquires the bottom noise power value of the air interface pilot signal; and detects the average power of the air interface pilot signal.
  • the bottom noise power value and the average power level are compared, and a power feature matching curve is generated according to the comparison result.
  • the power feature matching curve is compared with the set power feature window. If it matches, it is determined that the location of the cell DWPTS is searched, and the lock indication signal is output.
  • the DWPTS pilot detection module performs a pilot search using a feature window method, and the bottom layer is implemented using an FPGA (Field Programmable Gate Array).
  • the SYNC_DL code has 64chip (1.28Mcps) for full power transmission, and 48chip and 96chip guard slots are not signaled before and after SYNC_DL.
  • the mean power in the protection time slot is the noise floor of the received signal, assuming that the signal greater than or equal to the noise floor A db is high (A can be set), and the signal below the noise floor Adb is low.
  • the power curve at the DWPTS position is 37.5us low, 50us high, and 75us low.
  • the pilot detection technique designed in this embodiment can be performed according to the following steps:
  • the time domain detection length of the bottom noise design in this embodiment is B, B ⁇ GP2/2.
  • the bottom noise value design M ms is updated once (M can be set), keeping the minimum value within M ms each time. Ensure that the interference function adapts to changes in the external environment and dynamically update the noise floor power value.
  • the mean power for obtaining the noise floor is defined as P1.
  • SYNC_DL is 50us long and has guard slots greater than 25us before and after. Therefore, in this design, the length of the power matching window is set to 100us. Since the detection length in step 2 is C, in the case where the particle size is C, 100us is divided into 100/C aliquots. Therefore, in step 2, C needs to be designed to be a common divisor of 100us, so that the number of high and low levels obtained in step 3 is exactly an integer. Through the above design, the high and low levels stored in the cache RAM should be 25/C low level, 50/C high level, and 25/C high level.
  • an interference source is generated in the FPGA according to the lock indication signal generated in step 5 above.
  • the interference source is a random sequence, and the data source is modulated by the medium frequency to the application frequency of the TDS network.
  • the receiver described in the embodiments of the present invention supports the F-band (1880-1920 MHz) and the A-band (2015-2025 MHz).
  • an interference signal is sent to the air interface at the location of the cell DWPTS, so that the interference signal is superimposed with the air interface pilot signal, and then the air interface is transmitted.
  • the interference signal is superimposed on the air interface pilot signal and then transmitted outside the air interface, so that the interference of the interference signal can prevent the mobile terminal and the like from searching for the air interface pilot signal, that is, the mobile terminal and the like cannot find the base station.
  • the cell information is such that the base station cannot be accessed.
  • the interference sequence can only be transmitted at the downlink pilot position.
  • the interference signal of Figure 5 is designed, the interference signal is transmitted in the TS0 area, and the interference signal of less than 50us width is transmitted in the SYNC_DL position. Since the SYNC_DL time domain width of the air interface is larger than the interference signal, it does not cause a false positive when generating the power matching curve. Moreover, after the actual measurement, the interference effect is best when the interference signal is also transmitted in the TS0 area.
  • an interference signal is sent to the air interface at the location of the cell DWPTS.
  • the jammer searches for the pilot signal of the air interface base station and transmits a high power interference signal to the air interface, and the transmitted interference signal is superimposed with the pilot signal of the base station.
  • the interference signal transmitted by itself is high, which may block the reverse link device of the interference machine.
  • the interference signal may affect the judgment of the interference signal to the air interface pilot signal.
  • the reverse gain control module sets an initial attenuation value and the system continuously monitors The lock indication signal of the pilot detection module, when monitoring that the jammer continues to be unable to lock, the system increases the gain of the reverse gain control module until the lock indication is monitored to be normal.
  • the noise floor of the jammer obtained according to the detection length of 20us during the initial search is -98dbm. Since the pilot signal of the air interface has a good signal-to-noise ratio with respect to the noise floor, it is assumed that the power of the pilot position reaches about -70 dBm. Setting the noise greater than the bottom noise of 6dm is a high-level signal, so that the pilot position will obtain the first 25us length low level, then 50us high level, then 25us low level power window. This feature matches the designed power feature window and outputs a lock indication signal indicating that the internal disturbance source generation module begins to generate an interference source.
  • the noise floor of the jammer changes rapidly.
  • the noise floor changes to -80dbm
  • the jammer can adapt to the environmental changes and ensure that the generated power window is not deformed. If it is a method of fixed detection threshold, if the detection threshold is designed below -80dbm, the power feature window cannot be obtained.
  • the jammer starts to transmit the interference signal according to the designed time domain characteristics, and the interference signal is amplified by the jammer to the antenna port output, and the output power reaches 45dbm.
  • the interference signal is designed to transmit the interference signal at the pilot position and the TS0 position.
  • the transmission length of the pilot position needs to be less than the 50us length of the pilot signal sent by the air interface.
  • the interference signal sent by the embodiment of the present invention is only 40 us, so that the interference signal is in the air interface. Within the frequency signal, when the air interface pilot signal is superimposed and entered into the RRU, the judgment of the power characteristic curve is not affected.
  • the 45dbm interference signal is at the same frequency as the received signal, so it will couple into the receiving channel through the air interface.
  • the received signal has an amplification function, so that the power to the intermediate frequency ADC port exceeds its saturated power.
  • the automatic gain adjustment technology designed by the embodiment of the invention can adjust the gain adjustment module of the interference link of the jammer in real time, and monitor the lock indication signal in real time. If the lock cannot be locked for a period of time, the attenuation amount of the signal is adjusted and re-detected until stable locking. . In addition, if the pilot signal has a more serious tailing, all power window detection methods will fail. At this time, the gain adjustment module is The input signal is attenuated, and the tailing of the pilot signal can be reduced, which serves as a signal shaping function.
  • the algorithm part of the embodiment of the invention is implemented by using an FPGA (Field Programmable Gate Array), which has a fast running speed and can track and lock the air interface pilot signal in real time.
  • FPGA Field Programmable Gate Array
  • the logic resources used are small, only two DSP cores are needed, and a small amount of lookup table resources can be used to complete the operation, which saves system cost compared with a complicated filter designed.
  • the embodiment of the invention detects the air interface pilot signal based on the power feature window method, combines the dynamic gain control technology, and the anti-self-interference optimization, so that the interference function can effectively adapt to the interference of the spontaneous interference signal and the complex external environment, and the stable locked cell guide
  • the frequency signal effectively suppresses the access of the mobile phone user within the interference range to the TDS network.
  • the embodiment of the present invention further provides a jammer including the downlink pilot suppression device as described above, and its function and principle. Please refer to the foregoing embodiment, and details are not described herein again.
  • all or part of the steps of the above embodiments may also be implemented by using an integrated circuit. These steps may be separately fabricated into individual integrated circuit modules, or multiple modules or steps may be fabricated into a single integrated circuit module. achieve.
  • the devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.
  • Each device/function module/function unit in the above embodiment is implemented in the form of a software function module. And when sold or used as a stand-alone product, it can be stored on a computer readable storage medium.
  • the above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.
  • the above technical solution enables the interference function to effectively adapt to the interference of the spontaneous interference signal and the complex external environment, stably lock the pilot signal of the cell, and effectively suppress the mobile phone user in the interference range from accessing the TDS network.

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Abstract

一种下行导频抑制方法、装置及干扰机，其方法包括：搜素空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置；当搜索到所述小区DWPTS的位置时，生成干扰源；基于干扰源并结合自动增益控制技术，在小区DWPTS的位置向空口发送干扰信号，以使干扰信号与空口导频信号叠加后进行空口传输，防止手机等移动终端搜索到空口导频信号。上述技术方案使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定的锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。

Description

下行导频抑制方法、装置及干扰机 技术领域
本文涉及通讯技术领域，尤其涉及一种TD-SCDMA(TDS，TimeDivision-SynchronousCodeDivisionMultipleAccess，时分同步码分多址)下行导频抑制方法、装置及干扰机。
背景技术
目前，TD-SCDMA无线网络在国内大规模的覆盖，在某些应用场景下需要抑制某区域的用户接入3G网络。为了达到抑制手机用户接入基站，首先需要了解手机的小区搜索过程。手机开机搜索、登录到合适小区的过程定义为小区搜索。手机开机后，TD-SCDMA的小区搜索过程大致可以分为以下几个步骤：
(1)搜索DwPTS(Downlink Pilot Time Slot，下行导频)的位置，获取DwPTS时隙中SYNC_DL(下行同步序列码)；
(2)识别扰码和基本中间码；
(3)实现复帧同步；
(4)读广播信道BCH(broadcast channel)信息。
根据手机小区搜索的步骤来看，第一步找到小区Dwpts的位置是小区搜索成功的基础。目前，采用的抑制手机用户接入基站的干扰机的原理即为：将无线干扰装置实时同步到宏基站小区，在Dwpts位置发送干扰码，这样在干扰区域内的手机用户将无法同步到TD-SCDMA网络。干扰机同步到宏站小区的过程与手机小区搜索的第一步一致，即搜索空口的Dwpts的位置。
在搜索Dwpts位置时，目前普遍的做法是滑动相关法和特征窗法搜索Dwpts的大致位置。
滑动相关的基本原理为：利用SYNC码的相关特征，将32组SYNC_DL码分别与接收信号做滑动相关，当找到最大相关值时，则找到了SYNC_DL的位置以及使用了哪组SYNC_DL码。
特征窗法的基本原理为：利用Dwpts的功率形状来确定Dwpts的大致位置。TD-SCDMA无线帧结构将10ms的无线帧分成两个5ms的子帧，每个子帧中有7个常规时隙(包括TS0，广播信道)和3个特殊时隙。三个特殊时隙分别为下行导频时隙DwPTS、保护时隙GP和上行导频时隙UpPTS。TDS的物理子帧结构如图1所示。SYNC_DL左右均有一段保护间隔，在这段保护期内基站和移动终端都不发送信号，而SYNC_DL是以全功率级别发射，所以SYNC_DL本身的功率相对两边的保护时隙功率要大很多，因此用SYNC_DL的功率与两边GP时隙的功率做比较，就可以确定出SYNC_DL的大致位置。
但是，由于干扰机设计时不需要知道小区的SYNC_DL码为多少，使用滑动相关的方法会造成过多的运算浪费，且相关器设计复杂；而相关的特征窗法，则无法有效的适应自发干扰信号的干扰和复杂的外界环境。
发明内容
本发明实施例提供一种下行导频抑制方法、装置及干扰机，以解决如何有效的适应自发干扰信号的干扰和复杂的外界环境，稳定地锁定小区的导频信号的技术问题。
为了达到上述目的，本发明实施例提出一种下行导频抑制方法，包括：
搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置；
当搜索到所述小区DWPTS的位置时，生成干扰源；
基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
可选地，所述搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置的步骤包括：
接收小区发出的空口导频信号；
动态获取所述空口导频信号的底噪功率值；
检测所述空口导频信号的均值功率；
比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线；
将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
可选地，将所述功率特征匹配曲线与设定的功率特征窗进行对比包括：
结合抗噪处理技术将所述功率特征匹配曲线与设定的功率特征窗进行对比。
可选地，所述基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号的步骤包括：
在发送所述干扰信号时，持续监测所述锁定指示信号，在监测不到所述锁定指示信号时，提高设定的反向增益控制模块的增益，直至监控到锁定指示正常，所述反向增益控制模块设置有一初始衰减值。
可选地，所述方法还包括：
除在小区DWPTS的位置向空口发送干扰信号外，还在
常规时隙TS0区域向空口发送干扰信号；在所述小区DWPTS的位置的干扰信号的发送长度小于所述空口导频信号的发送长度。
可选地，所述方法还包括：
对接收的所述空口导频信号进行滤波、低噪放、增益调整和/或下变频至中频信号。
可选地，所述方法还包括：
将所述干扰源上变频至射频信号；以及对发送的干扰信号进行功率放大及滤波。
本发明实施例还提出一种下行导频抑制装置，包括：
导频搜索模块，设置为搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置；
生成模块，设置为当搜索到所述小区DWPTS的位置时，生成干扰源；
发送模块，设置为基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
可选地，所述导频搜索模块，是设置为接收小区发出的空口导频信号；动态获取所述空口导频信号的底噪功率值；检测所述空口导频信号的均值功率；比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线；将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
可选地，所述导频搜索模块是设置为通过如下方式实现将所述功率特征匹配曲线与设定的功率特征窗进行对比：
结合抗噪处理技术，将所述功率特征匹配曲线与设定的功率特征窗进行对比。
可选地，所述发送模块，是设置为在发送所述干扰信号时，持续监测所述锁定指示信号，在监测不到所述锁定指示信号时，提高设定的反向增益控制模块的增益，直至监控到锁定指示正常，所述反向增益控制模块设置有一初始衰减值。
可选地，所述发送模块，还设置为在所常规时隙TS0区域向空口发送干扰信号；在所述小区DWPTS的位置的干扰信号的发送长度小于所述空口导频信号的发送长度。
可选地，所述导频搜索模块，还设置为对接收的所述空口导频信号进行滤波、低噪放、增益调整和/或下变频至中频信号。
可选地，所述发送模块，还设置为将所述干扰源上变频至射频信号；以及对发送的干扰信号进行功率放大及滤波。
本发明实施例还提出一种干扰机，包括权如上所述的装置。
本发明实施例还提出一种计算机存储介质，所述计算机存储介质中存储 有计算机可执行指令，所述计算机可执行指令用于执行上述的方法。
本发明实施例提出的一种下行导频抑制方法、装置及干扰机，基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定的锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
附图概述
图1是TD-SCDMA子帧结构示意图；
图2是本发明实施例下行导频抑制方法的流程示意图；
图3是本发明实施例设计的干扰机系统架构示意图；
图4是本发明实施例生成的功率特征匹配曲线示意图；
图5是本发明实施例干扰机干扰信号输出示意图；
图6是本发明实施例下行导频抑制装置的功能模块示意图。
本发明的较佳实施方式
本发明实施例中，基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定地锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
如图2所示，本发明实施例提出一种下行导频抑制方法，包括：
步骤S101，搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置；
如前所述，在搜索Dwpts位置时，目前普遍的做法是采用滑动相关法和特征窗法搜索Dwpts的大致位置。
由于干扰机设计时不需要知道小区的SYNC_DL码为多少，使用滑动相 关的方法会造成过多的运算浪费，且相关器设计复杂；而相关的特征窗法，则无法有效的适应自发干扰信号的干扰和复杂的外界环境。
本发明实施例方案设计一种适应室内和室外环境的TD-SCDMA干扰机，基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
可选地，如图3所示，本实施例设计的干扰机系统由天线(包括接收天线和发射天线)、滤波器、功放单元、低噪放单元、增益调整单元、中射频链路单元、DWPTS导频检测模块、干扰源生成模块组成。
接收天线设置为接收小区发出的空口导频信号，使用全向天线作为接收天线。发射天线设置为向空口发送导频干扰源，使用定向天线将干扰信号发送到固定的区域。
滤波器设置为滤除除TD-SCDMA之外的信号。
功放单元、低噪放单元设置为放大接收信号和发送信号。
发送方向的增益调整模块设置为实现发送信号的功率调节，控制干扰区域范围。反向增益调整模块设置为实现反向接收的动态增益控制，增加干扰机的抗干扰性能。
反向接收的中射频链路单元设置为将接收到的射频信号下变频到中频信号。前向发送的中射频链路单元设置为将导频干扰源生成模块产生的干扰源上变频至射频，通过功放放大后发送至空口。
基于上述系统结构，在本实施例方案中，首先，基于功率特征窗法搜索小区DWPTS的位置，过程如下：
干扰机接收小区发出的空口导频信号；动态获取所述空口导频信号的底噪功率值；检测所述空口导频信号的均值功率。
之后，比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线。
最后，将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
可选地，DWPTS导频检测模块使用特征窗法进行导频搜索，底层使用FPGA(现场可编程门阵列)实现。如前所述，SYNC_DL码有64chip(1.28Mcps)为满功率发射，SYNC_DL前后分别有48chip和96chip的保护时隙没有信号发送。在时域上，保护时隙内的均值功率即为接收信号的底噪，假设大于或等于底噪A db的信号为高电平(A可设置)，小于底噪Adb的信号为低电平，理想情况下，DWPTS位置的功率曲线为37.5us低电平，50us高电平，75us低电平。本实施例设计的导频检测技术可按照下面步骤来进行：
(1)动态获取底噪值。由于保护时隙的功率接近于底噪，为了保证检测的时域均值功率能落在保护时隙，本实施例设计底噪的时域检测长度为B，B<GP2/2。底噪值设计M ms更新一次(M可设置)，每次保持M ms内的最小值。保证干扰机能适应外部环境的变化，动态更新底噪功率值。在本步骤中定义获得底噪的均值功率为P1。
(2)按照检测长度为C(单位us，C可设置)的颗粒度检测输入信号的均值功率。为了保证功率计算的正确性，需要保证一定量的采样点数。在本步骤中定义获得接收信号的实时均值功率为P2。
(3)比较输入信号的实时均值功率P2与底噪的均值功率P1的大小。如果P2比P1大Adb，则输入信号为高电平，如果P2与P1的差小于或等于Adb，则输入信号为低电平。根据此规则，将输入的高低电平信号依次输入RAM中缓存，生成的功率特征匹配曲线如图4所示。
(4)功率特征窗设计。SYNC_DL为50us长度，前后均有大于25us的保护时隙。因此在本设计中，设置功率匹配窗的长度为100us。由于在步骤2中的检测长度为C，在颗粒度为C的情况下，100us被分为100/C等份。因此在步骤2中，C需要设计为100us的公约数，这样在步骤3中得到的高低电平数目正好为整数。通过上面的设计，存入缓存RAM中的高低电平依次应为25/C个低电平，50/C个高电平，25/C个高电平。
(5)将缓存RAM内的功率电平与功率特征窗进行对比，如果匹配，则表示搜索到DWPTS的位置，输出锁定指示信号。
在本步骤中，将缓存RAM内的功率电平与功率特征窗比较时，需要加入抗噪的设计。由于外部多径以及其他噪声的干扰，导致在SYNC_DL信号 的爬升和下降区间比较缓，功率判断容易出现错误。另外，由于实时功率检测颗粒度为C，带来一定的检测误差。因此，在本设计的特征窗匹配环节，需要预留一定的余量，设计SYNC_DL区域高电平数目需要大于D(可以设置)，前后保护间隔区域高电平数目需要分别小于E(可以设置)和F(可以设置)。
步骤S102，当搜索到所述小区DWPTS的位置时，生成干扰源；
当搜索到所述小区DWPTS的位置后，根据步骤S101中第5步生成的锁定指示信号，在FPGA内生成干扰源。干扰源为随机序列，数据源经中射频调制至TDS网络的应用频点。本发明实施例所描述的接收机支持F频段(1880-1920MHz)与A频段(2015-2025MHz)。
步骤S103，基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
干扰信号与空口导频信号叠加后在空口向外传输，这样通过干扰信号的干扰，达到防止手机等移动终端搜索到空口导频信号的目的，也就是说，手机等移动终端就不能搜到基站的小区信息，这样就接入不了基站。
可选地，干扰机工作时只影响某区域内的手机用户不能接入TDS网络，但不能影响基站正常工作，这样干扰区域之外的手机用户可以正常运转。因此只能在下行导频位置发送干扰序列。
考虑到干扰机发送的干扰信号通过反向进入干扰机，会影响导频检测模块对SYNC_DL的搜索。因此，本设计中设计了如图5的干扰信号，在TS0区域发送干扰信号，在SYNC_DL位置发送小于50us宽度的干扰信号。由于空口的SYNC_DL时域宽度大于干扰信号，这样在生成功率匹配曲线时不会引起误判。并且，经过实测，在TS0区域也发送干扰信号时干扰效果最好。
可选地，本实施例中，结合自动增益控制技术，在小区DWPTS的位置向空口发送干扰信号。
阐述如下：
干扰机搜索空口基站的导频信号，并发送大功率的干扰信号至空口，发 送的干扰信号与基站的导频信号叠加。自身发送的干扰信号功率大，可能阻塞干扰机反向链路器件，另外干扰信号会影响干扰机对空口导频信号的判断。本设计使用动态增益控制技术，并设计特殊的输出干扰信号，有效的较低了自干扰的影响。
动态增益控制技术的原理如下：
干扰机上电后，反向增益控制模块设置一个初始衰减值，系统持续监测导频检测模块的锁定指示信号，当监测到干扰机持续不能锁定的情况时，系统提高反向增益控制模块的增益，直到监控到锁定指示正常。
下面结合实例来描述上述过程。
假设露天环境下，干扰初始搜索时按照20us的检测长度得到的干扰机的底噪值为-98dbm。由于在室外，空口的导频信号相对底噪有较好的信噪比，假设导频位置的功率达到-70dbm左右。设定大于底噪6dm即为高电平信号，这样在导频位置会获得先25us长度低电平，然后50us高电平，再25us低电平的功率窗。这个特征吻合设计的功率特征窗，输出锁定指示信号，指示内部干扰源生成模块开始生成干扰源。
由于复杂的干扰环境的影响，干扰机的底噪迅速变化，当底噪变化到-80dbm时，由于有动态底噪检测，干扰机可以适应环境的变化，保证生成的功率窗不变形。如果是固定检测门限的方法，如果检测门限设计在-80dbm以下时，则无法得到功率特征窗。
当搜索到导频信号后，干扰机开始按照设计的时域特征发送干扰信号，干扰信号通过干扰机放大到天线口输出，输出功率达到45dbm。干扰信号设计为在导频位置和TS0位置发送干扰信号，导频位置的发送长度需要小于空口发出的导频信号的50us长度，本发明实施例发送的干扰信号只有40us，这样干扰信号在空口导频信号之内，和空口导频信号叠加后进入RRU时不会影响功率特征曲线的判断。
45dbm的干扰信号由于与接收的信号同频率，这样会通过空口耦合向外传输。
相比相关技术，本发明实施例中，由于反向链路有低噪放等器件，对接收的信号还有放大的功能，这样到中频ADC口的功率会超过其饱和功率。本发明实施例设计的自动增益调整技术可以实时的调整干扰机接收链路的增益调整模块，实时监控锁定指示信号，如果一段时间不能锁定，则调整信号的衰减量，重新再检测，直到稳定锁定。另外，如果导频信号有比较严重的拖尾的情况发生时，所有功率窗检测的方法都会失效。此时，增益调整模块自动对输入的信号进行衰减，导频信号的拖尾能消减，起到了信号整形的作用。
另外，本发明实施例算法部分使用FPGA(现场可编程门阵列)实现，运行速度快，能实时的跟踪锁定空口导频信号。使用的逻辑资源少，只需要两个DSP核，少量的查找表资源即可完成运算，相比设计复杂的相关滤波器而言，节约了系统成本。
本发明实施例基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定的锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
如图6所示，本发明实施例提出一种下行导频抑制装置，该装置承载于干扰机中，该装置包括：导频搜索模块201、生成模块202及发送模块203，其中：
导频搜索模块201，设置为搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置；该导频搜索模块201可以为图3所示的DWPTS导频检测模块；
生成模块202，设置为当搜索到所述小区DWPTS的位置时，生成干扰源；该生成模块202可以为图3所示的干扰源生成模块；
发送模块203，设置为基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
可选地，如前所述，在搜索Dwpts位置时，目前普遍的做法是采用滑动相关法和特征窗法搜索Dwpts的大致位置。
由于干扰机设计时不需要知道小区的SYNC_DL码为多少，使用滑动相关的方法会造成过多的运算浪费，且相关器设计复杂；而相关的特征窗法，则无法有效的适应自发干扰信号的干扰和复杂的外界环境。
本发明实施例方案设计一种适应室内和室外环境的TD-SCDMA干扰机，基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
可选的，所述导频搜索模块，是设置为接收小区发出的空口导频信号；动态获取所述空口导频信号的底噪功率值；检测所述空口导频信号的均值功率；比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线；将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
可选的，所述导频搜索模块是设置为通过如下方式实现将所述功率特征匹配曲线与设定的功率特征窗进行对比：结合抗噪处理技术将所述功率特征匹配曲线与设定的功率特征窗进行对比。
可选的，所述发送模块，是设置为在发送所述干扰信号时，持续监测所述锁定指示信号，在监测不到所述锁定指示信号时，提高设定的反向增益控制模块的增益，直至监控到锁定指示正常，所述反向增益控制模块设置有一初始衰减值。
可选的，所述发送模块，还设置为在常规时隙TS0区域向空口发送干扰信号；在所述小区DWPTS的位置的干扰信号的发送长度小于所述空口导频信号的发送长度。
可选的，所述导频搜索模块，还设置为对接收的所述空口导频信号进行滤波、低噪放、增益调整和/或下变频至中频信号。
可选的，所述发送模块，还设置为将所述干扰源上变频至射频信号；以及对发送的干扰信号进行功率放大及滤波。
可选地，如图3所示，本实施例设计的干扰机系统由天线(包括接收天线和发射天线)、滤波器、功放单元、低噪放单元、增益调整单元、中射频链路单元、DWPTS导频检测模块、干扰源生成模块组成。
接收天线设置为接收小区发出的空口导频信号，使用全向天线作为接收天线。发射天线设置为向空口发送导频干扰源，使用定向天线将干扰信号发送到固定的区域。
滤波器设置为滤除除TD-SCDMA之外的信号。
功放单元、低噪放单元设置为放大接收信号和发送信号。
发送方向的增益调整模块设置为实现发送信号的功率调节，控制干扰区域范围。反向增益调整模块设置为实现反向接收的动态增益控制，增加干扰机的抗干扰性能。
反向接收的中射频链路单元设置为将接收到的射频信号下变频到中频信号。前向发送的中射频链路单元设置为将导频干扰源生成模块产生的干扰源上变频至射频，通过功放放大后发送至空口。
基于上述系统结构，在本实施例方案中，首先，基于功率特征窗法搜索小区DWPTS的位置，过程如下：
干扰机接收小区发出的空口导频信号；动态获取所述空口导频信号的底噪功率值；检测所述空口导频信号的均值功率。
之后，比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线。
最后，将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
可选地，DWPTS导频检测模块使用特征窗法进行导频搜索，底层使用FPGA(现场可编程门阵列)实现。如前所述，SYNC_DL码有64chip(1.28Mcps)为满功率发射，SYNC_DL前后分别有48chip和96chip的保护时隙没有信号发送。在时域上，保护时隙内的均值功率即为接收信号的底噪，假设大于或等于底噪A db的信号为高电平(A可设置)，小于底噪Adb的信号为低电平， 理想情况下，DWPTS位置的功率曲线为37.5us低电平，50us高电平，75us低电平。本实施例设计的导频检测技术可按照下面步骤来进行：
(1)动态获取底噪值。由于保护时隙的功率接近于底噪，为了保证检测的时域均值功率能落在保护时隙，本实施例设计底噪的时域检测长度为B，B<GP2/2。底噪值设计M ms更新一次(M可设置)，每次保持M ms内的最小值。保证干扰机能适应外部环境的变化，动态更新底噪功率值。在本步骤中定义获得底噪的均值功率为P1。
(2)按照检测长度为C(单位us，C可设置)的颗粒度检测输入信号的均值功率。为了保证功率计算的正确性，需要保证一定量的采样点数。在本步骤中定义获得接收信号的实时均值功率为P2。
(3)比较输入信号的实时均值功率P2与底噪的均值功率P1的大小。如果P2比P1大Adb，则输入信号为高电平，如果P2与P1的差小于或等于Adb，则输入信号为低电平。根据此规则，将输入的高低电平信号依次输入RAM中缓存。生成的功率特征匹配曲线如图4所示。
(4)功率特征窗设计。SYNC_DL为50us长度，前后均有大于25us的保护时隙。因此在本设计中，设置功率匹配窗的长度为100us。由于在步骤2中的检测长度为C，在颗粒度为C的情况下，100us被分为100/C等份。因此在步骤2中，C需要设计为100us的公约数，这样在步骤3中得到的高低电平数目正好为整数。通过上面的设计，存入缓存RAM中的高低电平依次应为25/C个低电平，50/C个高电平，25/C个高电平。
(5)将缓存RAM内的功率电平与功率特征窗进行对比，如果匹配，则表示搜索到DWPTS的位置，输出锁定指示信号。
在本步骤中，将缓存RAM内的功率电平与功率特征窗比较时，需要加入抗噪的设计。由于外部多径以及其他噪声的干扰，导致在SYNC_DL信号的爬升和下降区间比较缓，功率判断容易出现错误。另外，由于实时功率检测颗粒度为C，带来一定的检测误差。因此，在本设计的特征窗匹配环节，需要预留一定的余量，设计SYNC_DL区域高电平数目需要大于D(可以设置)，前后保护间隔区域高电平数目需要分别小于E(可以设置)和F(可以设置)。
当搜索到所述小区DWPTS的位置后，根据上述第5步生成的锁定指示信号，在FPGA内生成干扰源。干扰源为随机序列，数据源经中射频调制至TDS网络的应用频点。本发明实施例所描述的接收机支持F频段(1880-1920MHz)与A频段(2015-2025MHz)。
之后，基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
干扰信号与空口导频信号叠加后在空口向外传输，这样通过干扰信号的干扰，达到防止手机等移动终端搜索到空口导频信号的目的，也就是说，手机等移动终端就不能搜到基站的小区信息，这样就接入不了基站。
可选地，干扰机工作时只影响某区域内的手机用户不能接入TDS网络，但不能影响基站正常工作，这样干扰区域之外的手机用户可以正常运转。因此只能在下行导频位置发送干扰序列。
考虑到干扰机发送的干扰信号通过反向进入干扰机，会影响导频检测模块对SYNC_DL的搜索。因此，本设计中设计了如图5的干扰信号，在TS0区域发送干扰信号，在SYNC_DL位置发送小于50us宽度的干扰信号。由于空口的SYNC_DL时域宽度大于干扰信号，这样在生成功率匹配曲线时不会引起误判。并且，经过实测，在TS0区域也发送干扰信号时干扰效果最好。
可选地，本实施例中，结合自动增益控制技术，在小区DWPTS的位置向空口发送干扰信号。
阐述如下：
干扰机搜索空口基站的导频信号，并发送大功率的干扰信号至空口，发送的干扰信号与基站的导频信号叠加。自身发送的干扰信号功率大，可能阻塞干扰机反向链路器件，另外干扰信号会影响干扰机对空口导频信号的判断。本设计使用动态增益控制技术，并设计特殊的输出干扰信号，有效的较低了自干扰的影响。
动态增益控制技术的原理如下：
干扰机上电后，反向增益控制模块设置一个初始衰减值，系统持续监测 导频检测模块的锁定指示信号，当监测到干扰机持续不能锁定的情况时，系统提高反向增益控制模块的增益，直到监控到锁定指示正常。
下面结合实例来描述上述过程。
假设露天环境下，干扰初始搜索时按照20us的检测长度得到的干扰机的底噪值为-98dbm。由于在室外，空口的导频信号相对底噪有较好的信噪比，假设导频位置的功率达到-70dbm左右。设定大于底噪6dm即为高电平信号，这样在导频位置会获得先25us长度低电平，然后50us高电平，再25us低电平的功率窗。这个特征吻合设计的功率特征窗，输出锁定指示信号，指示内部干扰源生成模块开始生成干扰源。
由于复杂的干扰环境的影响，干扰机的底噪迅速变化，当底噪变化到-80dbm时，由于有动态底噪检测，干扰机可以适应环境的变化，保证生成的功率窗不变形。如果是固定检测门限的方法，如果检测门限设计在-80dbm以下时，则无法得到功率特征窗。
当搜索到导频信号后，干扰机开始按照设计的时域特征发送干扰信号，干扰信号通过干扰机放大到天线口输出，输出功率达到45dbm。干扰信号设计为在导频位置和TS0位置发送干扰信号，导频位置的发送长度需要小于空口发出的导频信号的50us长度，本发明实施例发送的干扰信号只有40us，这样干扰信号在空口导频信号之内，和空口导频信号叠加后进入RRU时不会影响功率特征曲线的判断。
45dbm的干扰信号由于与接收的信号同频率，这样会通过空口耦合进入接收通道。
相比相关技术，本发明实施例中，由于反向链路有低噪放等器件，对接收的信号还有放大的功能，这样到中频ADC口的功率会超过其饱和功率。本发明实施例设计的自动增益调整技术可以实时的调整干扰机接收链路的增益调整模块，实时监控锁定指示信号，如果一段时间不能锁定，则调整信号的衰减量，重新再检测，直到稳定锁定。另外，如果导频信号有比较严重的拖尾的情况发生时，所有功率窗检测的方法都会失效。此时，增益调整模块自 动对输入的信号进行衰减，导频信号的拖尾能消减，起到了信号整形的作用。
另外，本发明实施例算法部分使用FPGA(现场可编程门阵列)实现，运行速度快，能实时的跟踪锁定空口导频信号。使用的逻辑资源少，只需要两个DSP核，少量的查找表资源即可完成运算，相比设计复杂的相关滤波器而言，节约了系统成本。
本发明实施例基于功率特征窗法检测空口导频信号，结合动态增益控制技术，以及抗自干扰优化，使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定的锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。
本发明实施例还提出一种包括如上所述下行导频抑制装置的干扰机，其功能特点及原理，请参照上述实施例，在此不再赘述。
以上所述仅为本发明的优选实施例，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或流程变换，或直接或间接运用在其它相关的技术领域，均同理包括在本发明的专利保护范围内。
本领域普通技术人员可以理解上述实施例的全部或部分步骤可以使用计算机程序流程来实现，所述计算机程序可以存储于一计算机可读存储介质中，所述计算机程序在相应的硬件平台上(如系统、设备、装置、器件等)执行，在执行时，包括方法实施例的步骤之一或其组合。
可选地，上述实施例的全部或部分步骤也可以使用集成电路来实现，这些步骤可以被分别制作成一个个集成电路模块，或者将它们中的多个模块或步骤制作成单个集成电路模块来实现。
上述实施例中的各装置/功能模块/功能单元可以采用通用的计算装置来实现，它们可以集中在单个的计算装置上，也可以分布在多个计算装置所组成的网络上。
上述实施例中的各装置/功能模块/功能单元以软件功能模块的形式实现 并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。上述提到的计算机可读取存储介质可以是只读存储器，磁盘或光盘等。
工业实用性
上述技术方案使干扰机能有效的适应自发干扰信号的干扰和复杂的外界环境，稳定的锁定小区的导频信号，有效的抑制干扰范围内的手机用户接入TDS网络。

Claims (16)

  1. 一种下行导频抑制方法，包括：
    搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区下行导频DWPTS的位置；
    当搜索到所述小区DWPTS的位置时，生成干扰源；
    基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
  2. 根据权利要求1所述的方法，其中，所述搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区DWPTS的位置的步骤包括：
    接收小区发出的空口导频信号；
    动态获取所述空口导频信号的底噪功率值；
    检测所述空口导频信号的均值功率；
    比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线；
    将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
  3. 根据权利要求2所述的方法，其中，将所述功率特征匹配曲线与设定的功率特征窗进行对比包括：
    结合抗噪处理技术将所述功率特征匹配曲线与设定的功率特征窗进行对比。
  4. 根据权利要求2所述的方法，其中，所述基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号的步骤包括：
    在发送所述干扰信号时，持续监测所述锁定指示信号，在监测不到所述锁定指示信号时，提高设定的反向增益控制模块的增益，直至监控到锁定指示正常，所述反向增益控制模块设置有一初始衰减值。
  5. 根据权利要求2、3或4所述的方法，所述方法还包括：
    除在小区DWPTS的位置向空口发送干扰信号外，还在常规时隙TS0区域向空口发送干扰信号；在所述小区DWPTS的位置的干扰信号的发送长度小于所述空口导频信号的发送长度。
  6. 根据权利要求1所述的方法，所述方法还包括：
    对接收的所述空口导频信号进行滤波、低噪放、增益调整和/或下变频至中频信号。
  7. 根据权利要求1所述的方法，所述方法还包括：
    将所述干扰源上变频至射频信号；以及对发送的干扰信号进行功率放大及滤波。
  8. 一种下行导频抑制装置，包括：
    导频搜索模块，设置为搜索空口导频信号，根据所述空口导频信号，并基于功率特征窗法搜索小区下行导频DWPTS的位置；
    生成模块，设置为当搜索到所述小区DWPTS的位置时，生成干扰源；
    发送模块，设置为基于所述干扰源并结合自动增益控制技术，在所述小区DWPTS的位置向空口发送干扰信号，以使所述干扰信号与所述空口导频信号叠加后进行空口传输。
  9. 根据权利要求8所述的装置，其中，
    所述导频搜索模块，是设置为接收小区发出的空口导频信号；动态获取 所述空口导频信号的底噪功率值；检测所述空口导频信号的均值功率；比较所述底噪功率值与均值功率大小，根据比较结果生成功率特征匹配曲线；将所述功率特征匹配曲线与设定的功率特征窗进行对比，如果匹配，则判定搜索到小区DWPTS的位置，输出锁定指示信号。
  10. 根据权利要求9所述的装置，其中
    所述导频搜索模块是设置为通过如下方式实现将所述功率特征匹配曲线与设定的功率特征窗进行对比：
    结合抗噪处理技术将所述功率特征匹配曲线与设定的功率特征窗进行对比。
  11. 根据权利要求9所述的装置，其中，
    所述发送模块，是设置为在发送所述干扰信号时，持续监测所述锁定指示信号，在监测不到所述锁定指示信号时，提高设定的反向增益控制模块的增益，直至监控到锁定指示正常，所述反向增益控制模块设置有一初始衰减值。
  12. 根据权利要求9、10或11所述的装置，
    所述发送模块，还设置为在常规时隙TS0区域向空口发送干扰信号；在所述小区DWPTS的位置的干扰信号的发送长度小于所述空口导频信号的发送长度。
  13. 根据权利要求8所述的装置，
    所述导频搜索模块，还设置为对接收的所述空口导频信号进行滤波、低噪放、增益调整和/或下变频至中频信号。
  14. 根据权利要求8所述的装置，
    所述发送模块，还设置为将所述干扰源上变频至射频信号；以及对发送的干扰信号进行功率放大及滤波。
  15. 一种干扰机，包括权利要求8-14中任一项所述的装置。
  16. 一种计算机存储介质，所述计算机存储介质中存储有计算机可执行指令，所述计算机可执行指令用于执行权利要求1～7中任一项所述的方法。
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