Realize TD-SCDMA RF front-end full duplex testing apparatus and method
Technical field
The present invention relates to the full duplex testing apparatus and the method for radio-frequency front-end in a kind of TD-SCDMA of the realization system.
Background technology
TD-SCDMA is one of 3G (Third Generation) Moblie air interface technologies standard 3 big standards of the formal issue of the ITU of International Telecommunications Union, and its key technology has time division duplex technology, intelligent antenna technology, the associated detection technique that can adjust the up-downgoing switching point.The advantage outstanding behaviours of TD-SCDMA has obtained good equilibrium, there have been good sustained development and technology evolution in efficient support, the system self of mixed service between the anti-interference and power system capacity in system.
The multiple access access scheme of TD-SCDMA belongs to DS-SCDMA, and spreading rate is 1.28Mc/s, and apread spectrum bandwidth is about 1.6MHz, adopts FDMA (TDD) working method that does not need pair frequency.Its descending and up information is to transmit on the different time-gap of same carrier frequency.The physical channel of TD-SCDMA adopts four-layer structure: system-frame, radio frames, subframe and time slot/sign indicating number.Fig. 1 is the physical channel signal form of TD-SCDMA.Its frame structure is divided into the subframe of two 5ms with the radio frames of 10ms, and 7 conventional time slots and 3 special time slots are arranged in each subframe.Three special time slots are respectively descending pilot frequency time slot DwPTS, main protection time slot GP and uplink pilot time slot UpPTS.
Radio-frequency front-end is the important component part of TD-SCDMA Remote Radio Unit, it mainly is made up of power amplifier, LNA, circulator, radio-frequency (RF) switch and control switching circuit thereof, its function is to deliver to antenna after the radiofrequency signal power amplification from the base station, accept signal simultaneously from antenna, and will give the base station after its low noise amplification, its structured flowchart is seen shown in Figure 2.
Characteristics at TD-SCDMA up-downgoing time division duplex, the traditional test of radio-frequency front-end is divided into down going channel test and data feedback channel test, during descending test, send the test signal that downlink data is only arranged, after descending all index tests are over, change the connection of radio frequency, connect up link, carry out up test then, what send equally is the signal that upstream data is only arranged.In fact, the real operational environment of radio-frequency front-end then is that existing upstream data has downlink data again, and traditional method of testing can not reflect the radio-frequency performance of radio-frequency front-end really; Test down after the row index at every turn, need to change once connection, if by manual operations, this influences testing efficiency greatly in automatic test, and uses the radio frequency matrix, and cost is too high.
Summary of the invention
The problem that purpose of the present invention exists for the method for testing that overcomes above-mentioned existing radio-frequency front-end, the present invention utilizes the characteristics of TD-SCDMA radio-frequency front-end (hereinafter to be referred as FE), propose a kind of new simple, realization TD-SCDMA RF front-end full duplex testing apparatus and method that cost is low, the present invention can realize full duplex, once connecting can testing uplink and following row index, be that radio-frequency front-end works in existing upstream data and has again in the environment of downlink data and test, only need to connect the test that once just can finish up link and down link index, the centre does not need to change and connects, and plays in the automatic test and the equal effect of radio frequency matrix.
Technical scheme of the present invention:
Realize TD-SCDMA RF front-end full duplex testing apparatus, comprise signal source, frequency spectrograph, 3 isolators, 2 attenuators, circulator, mixer, power splitter, the test control panel, signal source links to each other with power splitter by radio frequency cable, signal source links to each other with the test control panel by triggering line, signal source links to each other with frequency spectrograph with reference clock by triggering line, power splitter one outlet is drawn by radio frequency cable and is inserted the descending input of radio-frequency front-end (Tx) end, power splitter another the outlet by radio frequency cable successively with isolator, attenuator, isolator, circulator, attenuator, mixer links to each other with frequency spectrograph, circulator inserts radio-frequency front-end antenna opening (Ant) end by another outlet that radio frequency cable is drawn, the last line output (Rx) of radio-frequency front-end end by radio frequency cable successively with isolator, mixer links to each other with frequency spectrograph, and the test control panel is connected by 10 core control lines with radio-frequency front-end.
The test signal of sending from signal source is the signal that uplink and downlink timeslot all has data, process power splitter one tunnel is as up input signal, one the tunnel as descending input signal, need not to change the connection of radio frequency line in the process of test, as long as just can obtain the test result of uplink and downlink by the minislot parameter of revising frequency spectrograph.
Characteristics at the TD-SCDMA signal, utilize passive devices such as a spot of circulator, isolator, attenuator, mixer to make up in a certain order, realization is to the full duplex of TD-SCDMA Remote Radio Unit (RRU) radio-frequency front-end, need not to change the test of connection midway, and test macro networking block diagram as shown in Figure 3.Test control panel among the figure provides the radio-frequency (RF) switch switch-over control signal for measured piece FE.Two of Event1, Event2 trigger line and are used to make signal source, frequency spectrograph, radio-frequency front-end three synchronous.Isolator 1, isolator 2 are used for the guard signal source and prevent the interference of the following line output of FE to input.The attenuator of 20dB is used to adjust the uplink and downlink input power, this connected mode, can guarantee descendingly to output to isolation between the input greater than 100dB, the up isolation that outputs between the input reaches more than the 80dB, thereby eliminate the power amplifier self-excitation, and interfering with each other between the input and output.
In the cycle of every subframe 5ms of TD-SCDMA signal, 0,4,5,6 is descending time slot, the bearing downlink business datum, 1,2,3 time slots are ascending time slot, send the test signal that 7 time slots all have data from signal source, this signal is through after the power splitter, and one the tunnel delivers to the Tx mouth of FE, and the Ant mouth is delivered on another road.0,4,5,6 time slots just during descending time slot, down link is got through, and promptly solid arrow is represented up link among Fig. 3, and up link disconnects under the control of test panel during this, thus what guarantee that frequency spectrograph collects is the signal of down link entirely.1,2,3 time slots just during the ascending time slot, control panel is got through up link, and the with dashed lines arrow is represented up link among Fig. 3, turn-offs down link.Thereby realize full duplex test to RF front-end module.
Method of testing of the present invention can be expressed as step:
The first step: the configuration signal source, utilize R﹠amp; Or the SignalStudio of the WinIQsim software Agilent company of S produces a frame TD-SCDMA base band data, and 7 time slots of these frame data all have data, comprises ascending pilot frequency and descending pilot frequency; Second step: the RF front-end full duplex testing apparatus is connected to radio-frequency front-end FE module corresponding ports; The 3rd step: utilize the test control panel, make radio-frequency front-end FE module work in dynamic switching state; The 4th cloth: to testing apparatus and device power, signal source accesses the signal of making in the first step, and send radiofrequency signal, frequency spectrograph is accepted uplink and downlink signals simultaneously, and can demodulation come out, by changing the minislot parameter setting of frequency spectrograph, thereby read the test result of uplink and downlink signals, minislot parameter is provided with: read the uplink test result when time slot is made as 1,2,3, time slot is made as and read descending test result at 0,4,5,6 o'clock.When the frequency spectrograph that uses is not supported the full-time crack of demodulation signal, allow signal source send out upward signal, downstream signal separately, frequency spectrograph comes the up-downgoing index of testing radio frequency front-end module at twice, and the FE module still works in switching state.
Adopt advantage of the present invention to be: the test platform cost of structure is low, simply is easy to realize, and is simple to operate.Can realize the full duplex test of FE module, the operational environment of real simulation FE module is the uplink and downlink signals coexistence, the real result of test.Once connect and just can test the uplink downlink index, the centre need not to change and connects, and has improved testing efficiency greatly, and then has reduced the cost of equipment, has improved the qualification rate of product.
Description of drawings
Fig. 1 is the physical channel signal format chart of TD-SCDMA.
Fig. 2 is the structured flowchart of radio-frequency front-end FE module.
Fig. 3 is the Test Networking figure of radio-frequency front-end FE module.
Among Fig. 3
Represent radio frequency cable
Represent the downstream signal trend
Represent the upward signal trend
Embodiment
In order to make the solution of the present invention clearer, the present invention is described in further details below in conjunction with example.Realize TD-SCDMA RF front-end full duplex testing apparatus, comprise signal source, frequency spectrograph, 3 isolators, 2 attenuators, circulator, mixer, power splitter, the test control panel, signal source links to each other with power splitter by radio frequency cable, signal source links to each other with the test control panel by triggering line, signal source links to each other with frequency spectrograph with reference clock by triggering line, power splitter one outlet is drawn by radio frequency cable and is inserted the descending input port of radio-frequency front-end (Tx) end, power splitter another the outlet by radio frequency cable successively with isolator, attenuator, isolator, circulator links to each other with the antenna opening (Ant) of radio-frequency front-end, circulator another the outlet by radio frequency cable successively with attenuator, mixer is connected to frequency spectrograph, the last line output Rx end of radio-frequency front-end by radio frequency cable successively with isolator, mixer links to each other with frequency spectrograph, and the test control panel is connected by 10 core control lines with radio-frequency front-end.Instrument is selected R﹠amp for use in this example; The SMU signal source of S company, FSQ frequency spectrograph, 1 watt radio-frequency front-end FE module.
First step configuration signal source.Utilize R﹠amp; The WinIQsim software of S produces a frame TD-SCDMA base band data, require 7 time slots (Slot) of these frame data all to have data, comprise ascending pilot frequency and descending pilot frequency, when the configuration base band data, can adjust the power ratio of uplink and downlink timeslot as required, thereby satisfy the different requirements of FE the up-downgoing input power.The base band data that produces is examined in the signal source with USB flash disk, in order to calling;
Second step: put up test platform according to connected mode shown in Figure 3, connect reference clock, trigger line, after also passive devices such as the mixer used in the system, power splitter, circulator, isolator can being connected, be fixed on a chest the inside, only need in the time of usefulness FE, signal source, frequency spectrograph are connected to corresponding ports and get final product;
The 3rd step: the school line, measure signal source respectively to antenna opening (Ant) port of FE, the line loss of descending input (Tx) port with signal source and frequency spectrograph, and frequency spectrograph is to the Ant port of FE, the line loss of last line output (Rx) port, and notes.
The 4th step: utilize the test control panel, make the FE module work in dynamic switching state, i.e. module real mode of operation in the middle of system, this mode are measured the characteristic that the index of coming could real reaction FE;
The 5th cloth: to testing apparatus and device power, signal source accesses the signal of making in the first step, and sends radiofrequency signal, by changing the minislot parameter setting of frequency spectrograph, thereby reads the test result of uplink and downlink signals.Read the uplink test result at 1,2,3 o'clock as time slot is made as, time slot is made as and read descending test result at 0,4,5,6 o'clock.If this method is applied in the automatization test system, reading all of the setting of these parameters and result finished by computer, and the advantage of this method of testing will be more obvious.