WO2010051660A1

WO2010051660A1 - Method for testing maximum power reduction

Info

Publication number: WO2010051660A1
Application number: PCT/CN2008/002152
Authority: WO
Inventors: 王曼
Original assignee: 中兴通讯股份有限公司
Priority date: 2008-11-04
Filing date: 2008-12-31
Publication date: 2010-05-14
Also published as: CN101741479B; CN101741479A

Abstract

A method for testing maximum power reduction (MPR) is provided in the present invention, which includes: establishing a test loop; and setting relevant parameters of MPR under the case that a user equipment UE being in the loop mode is assured; setting a test environment according to test requirements for MPR and adjacent channel leakage ratio (ACLR); sending the continuous uplink power control instructions to the UE so that system is able to enter into normal operation state; then testing ACLR value; resetting the relevant parameters of MPR, repeating the above steps and getting the new ACLR value, judging whether the ACLR value is up to snuff, if the result is “yes” then the MPR value being up to snuff, otherwise the MPR value being not up to snuff. Using the present invention, it can set relevant parameters of MPR and test whether MPR is up to snuff while testing ACLR. Thus the test parameters could be adjusted according to the actual instance and it can test MPR according to the actual requirement while testing ACLR, meanwhile test time could be saved and test steps could be reduced so that test process could be simplified.

Description

A test method for maximum transmit power backoff

Technical field

The present invention relates to a test method for MPR (Maximum Transmit Power Regression), and in particular to a test for adding an MPR (Maximum Transmit Power Backoff) to an ACLR (Adjacent Channel Leakage Ratio) test, and testing the adjacent channel leakage ratio. , determine whether the maximum launch power back-off meets the requirements.

Background technique

The nonlinear distortion of the RF power amplifier causes it to generate new frequency components, such as second harmonics for second-order distortion and third harmonics for third-order distortion. These new frequency components, if they fall within the passband, will directly interfere with the transmitted signal, and if they fall outside the passband, they will interfere with the signals of other channels. The amplifier has a linear dynamic range within which the output power of the amplifier increases linearly. As the input power continues to increase, the amplifier gradually enters the saturation region and the power gain begins to drop. The output power value, which is usually reduced to a lower gain than the linear gain ldB, is defined as the ldB compression point of the output power.

The maximum transmit power back-off is to back up the power amplifier's maximum input power by a few decibels, working at a level much smaller than the ldB compression point, leaving the power amplifier away from the saturation region and entering the linear working region, thereby improving the power amplifier. Third-order intermodulation coefficient.

The maximum transmit power backoff is also applied to the latest communication systems such as LTE (Long Term Evolution) and LTE+ (Enhanced Long Term Evolution). Orthogonal Frequency Division Multiplexing (OFDM) used in LTE is particularly suitable for high-speed transmission in wireless environments because it can effectively combat inter-symbol interference, and is widely considered to be an indispensable technology for next-generation communication systems. However, one of the main disadvantages of OFDM is that the peak-to-average power is high, and the high peak-to-average ratio causes the nonlinear distortion of the RF power amplifier, which causes many problems in the design of the system.

For RF devices, the device's reasonable maximum transmit power backoff value can be estimated by measuring the ldB compression point. However, after the maximum transmit power is retracted, it may have an impact on other parameters of the entire system. For each system, the maximum transmit power backoff value is defined by testing or simulation, but in the prior art, there is no tester that the maximum transmit power backoff value is reasonable. Summary of the invention

The invention provides a method for maximum transmit power backoff, which can accurately test whether the MPR value is reasonable.

The technical solution adopted by the present invention is: A test method for maximum transmit power back-off, comprising: establishing a test loop, and ensuring that the UE works in the loopback mode;

Set the parameters related to MPR;

Set the test environment according to the test requirements of MPR and ACLR;

Sending a continuous uplink power control command to the UE to put the system into a normal working state; measuring the ACLR value;

Reset the MPR related parameters, repeat the above steps, and measure the new ACLR to determine whether the ACLR value meets the requirements. If yes, the MPR value meets the requirements. Otherwise, the MPR value does not meet the requirements.

Further, the MPR related parameters include a modulation mode of the UE, a resource block RB, and a parameter channel.

Further, the modulation method includes QPSK and 16QAM.

Further, the test environment includes settings for temperature, voltage, frequency, and bandwidth of the test. Further, the setting of the bandwidth requires testing of all bandwidths of the system under test. Further, the system to be tested is an LTE system.

Further, the testing of the ACLR value includes the following steps:

Measuring the average power of the system main channel P;

Measuring the average power P1 of the first adjacent channel of the primary channel;

Measure the RRC average power 第一 and P2' of the first adjacent channel and the second adjacent channel;

Calculate ACLR=P/P1;

Calculate ACLR1= PI '/Ρ and ACLR2= P2'/P.

The invention provides a test method for maximum transmit power back-off, which is designed while testing ACLR Set the MPR related parameters and test whether the MPR meets the requirements. In this way, the test parameters can be adjusted according to the actual situation. The MPR is tested according to actual needs while measuring the ACLR, saving test time and reducing test steps, thereby simplifying the test process.

BRIEF abstract

Figure 1 is a schematic view of a test circuit of the present invention;

Figure 2 is a flow chart of the operation of the present invention;

Figure 3 is a schematic diagram of testing ACLR.

Preferred embodiment of the invention

The invention provides a test method for maximum transmit power back-off, and adds new test conditions based on the existing test ACLR to achieve the purpose of simultaneously testing ACLR and MPR.

The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

In the ACLR test, the test environment includes test temperature and test voltage. The test temperature is divided into extreme high temperatures and low temperatures (typically between -10 and +55 degrees Celsius), as well as general temperature conditions. The test voltage is also divided into high voltage, low voltage and general voltage conditions. The temperature and voltage settings during the test are generally combined by the above extreme cases, and the normal temperature and general voltage are measured.

The test frequency selects several representative frequencies in the general ACLR test, which are the low frequency zone, the intermediate frequency zone and the high frequency zone. For band1 (1920-1980MHz) of LTE, the low frequency range is 1922.5, 1925, 1927.5, 1930MHz, the IF area is 1950MHz, and the high frequency range is 1977.5, 1975, 1972.5, 1970MHz.

Taking the LTE system as an example, the MPR test is related to the modulation mode, system bandwidth, and whether it is a complete resource block. Therefore, in addition to the original parameters, it is necessary to additionally set these parameters when testing the ACLR to ensure that the test is performed under the correct conditions. .

In LTE systems, the bandwidth is 1.5MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz,

20 MHz. In the general ACLR test, the representative minimum bandwidth, maximum bandwidth and 5MHz are selected for testing. However, after adding the MPR test, all relevant bandwidths must be tested, because MPR related parameters such as RB (resource block, LTE radio resource unit), etc. The values are different under different bandwidths. However, after the MPR test is added, since the MPR value is different under different modulation modes, bandwidths, and RB conditions, the parameter settings of the test environment need to be changed.

The settings for the test temperature, test voltage, and test frequency are unchanged as described above, but the modulation method and RB settings must be added. The modulation methods are QPSK and 16QAM.

In addition, because of the different resource block requirements for different bandwidths, it is necessary to test all bandwidth conditions, rather than the normal ACLR, but to test values under typical bandwidth conditions. In addition, different maximum RB values need to be set according to different bandwidth conditions.

After the test environment is configured, set up the test link. As shown in Figure 1, enable the system to talk normally, and set the parameters of the system simulator and UE. Ensure that the UE works in loopback mode.

The complete test procedure of the present invention is shown in Figure 2:

Step 201: Set MPR related parameters, including modulation mode and RB;

Step 202: Set a new test environment according to the test requirements of MPR and ACLR, including temperature, voltage, frequency and bandwidth settings;

Step 203: Send a continuous uplink power control command to the UE to establish a test loop. Step 204: Test whether the ACLR meets the requirements. If the ACLR meets the requirements, the MPR meets the requirements, otherwise the MPR does not meet the requirements.

Then reset the MPR related parameters, repeat the above test steps, measure the new ACLR, and judge whether the ACLR meets the requirements;

The modulation mode and RB settings follow the MPR regulations. For example, when the modulation mode is 16QAM and the bandwidth is 1.5MHz, the MPR is 2, that is, when the MPR is 2, the modulation mode can be set to 16QAM and the bandwidth is set to 1.5MHz. Another example is that in the QPSK (Quadrature Phase Shift Keying) modulation mode, the system bandwidth is 5MHz, and when RB is greater than 8, the MPR must not be greater than 1.

The detailed steps for testing ACLR (Figure 3) are as follows:

Measuring the average power of the system main channel P;

Measuring the average power P1 of the first adjacent channel of the primary channel; Measure the RRC average power ΡΓ and P2' of the first adjacent channel and the second adjacent channel;

Calculate ACLR=P/P1;

Calculate ACLR1= PI '/Ρ and ACLR2= P2'/P, ACLR1 is the ACLR value of the first adjacent channel, and ACLR2 is the ACLR value of the second adjacent channel.

It is judged whether the calculated ACLR, ACLR1 and ACLR2 are reasonable, and the judgment standard is the same as the prior art.

Using the method of the present invention, after adding new test conditions (i.e., test conditions affecting MPR) when testing ACLR, each setting corresponds to an MPR value. If the measured ACLR is still in compliance with the original specifications, it is reasonable to say that this MPR maximum transmit power backoff is reasonable. If the measured ACLR is not in compliance with the new conditions (and these test conditions are based on MPR considerations), this MPR is unreasonable.

The present invention is applicable not only to LTE but also to systems in which resource blocks are used.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

Industrial applicability

Using the solution of the present invention, the MPR related parameters are set while testing the ACLR, and the MPR is tested to meet the requirements. In this way, the test parameters can be adjusted according to the actual situation, and the MPR can be tested according to actual needs while measuring ACLR, saving test time and reducing test steps, thereby simplifying the test process.

Claims

Claim

1. A test method for maximum transmit power back-off, characterized in that:

Establish a test loop, and ensure that the user equipment UE works in loopback mode;

Set the parameters related to the maximum transmit power backoff MPR;

Set the test environment according to the MPR and adjacent channel leakage ratio ACLR test requirements;

2. The method of claim 1 wherein:

The MPR related parameters include a modulation mode of the UE and a resource block RB.

3. The method of claim 2, wherein:

The modulation methods include QPSK and 16QAM.

4. The method of claim 1 wherein:

The test environment includes settings for temperature, voltage, frequency, and bandwidth of the test.

5. The method of claim 4 wherein:

The setting of the bandwidth requires testing of all bandwidths of the system under test.

6. The method of claim 5 wherein:

The system to be tested is an LTE system.

7. The method of claim 1 wherein the testing of the ACLR value comprises the steps of:

Measuring the average power of the system main channel P;

Measuring the average power P1 of the first adjacent channel of the primary channel; Measure the RRC average power 第一 and Ρ2' of the first adjacent channel and the second adjacent channel; calculate ACLR=P/P1;

Calculate ACLR1= Pl'/P and ACLR2= P2'/P.