1 Introduction
Test instruments and test systems are important links in the TD-LTE industry chain. At present, the demand for TD-LTE test instruments has covered all stages of the entire industry chain.
2 R & S LTE test solution
Rohde & Schwarz (R & S), as the largest supplier of test and measurement instruments in Europe, has strong R & D and production capabilities. Based on its leading position in the field of 2G and 3G testing, R & S has started tracking research on LTE from the early research and development stage, and has accumulated rich experience. In order to promote the development of the TD-LTE industry, R & S provides customers with a series of test and measurement solutions from LTE (including TD-LTE and FDD LTE) simulation, design, research and development, production, testing, etc., which can meet the needs of customers at all stages (see picture 1).
Figure 1 R & S LTE test solution
3 LTE chip and terminal development
(1) LTE signal generation and analysis
R & S signal sources such as SMU, AMU and SMBV series with options can generate LTE uplink / downlink RF or baseband signals in real time according to the specifications for component performance testing and terminal receiver testing; R & S FSx series spectrum And signal analyzer can analyze LTE uplink / downlink radio frequency or baseband signal, used for component performance test and terminal transmitter test.
Since the device under test may use a special digital baseband signal format, R & S provides EX-IQ-BOX to adapt to different digital baseband signal formats.
(2) LTE terminal protocol and IOT test
The LTE protocol stack test is used to verify some signaling functions, such as call establishment and release, call reconfiguration, state processing, and mobility. Interoperability (IOT) testing with 2G and 3G systems is another requirement for LTE. In order to ensure that the terminal's protocol stack and applications can handle high data rate data, it is necessary to test and verify the terminal throughput requirements. In the early days of LTE implementation, the R & D department needed a variety of test scenarios with various parameter configurations to test the LTE protocol stack. In addition, the LTE physical layer has many important functions, including cell search, HARQ protocol, scheduling, link adaptation, uplink time control, and power control, etc., and these processes have very strict timing requirements. Therefore, the physical layer also needs to be fully tested to ensure LTE performance.
R & S's CMW500 protocol tester can be used for protocol conformance testing, performance testing, and interoperability testing of LTE terminals. At the same time, R & S also provides virtual tester (Virtual Tester) software for PCs, enabling engineers to carry out protocol development work at an early stage. Therefore, the use of CMW500 enables parallel development, testing, and optimization of software and hardware, thereby speeding up the time to market.
CMW500 can provide the low-level and high-level programming interfaces required by the two protocol stack tests of MLAPI and LLAPI, so that developers can flexibly test the protocol stack at an early stage, and such tests are fully compatible with later conformance tests. Can save the time and cost of later testing.
(3) LTE terminal RF certification / pre-certification test
Before any communication terminal goes on the market, it needs to carry out strict terminal RF certification test. In order to support the RF development and certification testing of TD-LTE terminals, R & S launched the TS8980 LTE RF test system. TS8980 has 3 different configurations. Among them, TS8980S is a pre-certification platform for R & D customers. It can be flexibly configured according to customer needs for transmitter or receiver and performance testing; TS8980IB is a certification test platform that mainly performs in-band testing; TS8980FTA is a full certification test platform that can perform full certification tests required by GCF or PTCRB on terminals. For mobile terminal manufacturers, in addition to passing the above certification test, they may also need to pass the operator test. Such as US operators Verizon and AT & T, Japan NTT Docomo and so on. R & S and these operators have cooperated to develop some test cases that meet their special network access certification requirements. Mobile phone terminal manufacturers only need to purchase related equipment and test cases from R & S to build the same test environment in the laboratory, thus ensuring that they can pass Operator's network access test.
(4) LTE terminal RRM test
RRM (Radio Resource Management) testing is an important part of terminal certification testing. The LTE RRM test system launched by R & S can be integrated into the TS8980 RF conformance test system, share some hardware with it, and use the same control software R & S CONTEST to execute and analyze test cases. The RRM test system mainly includes the following hardware: the CMW500 system simulator can simulate LTE, WCDMA, CDMA and GSM cells, AMU200 is a baseband fading simulator, which can be connected to the CMW500 baseband for fading simulation of downlink signals, and the FSQ spectrum analyzer performs uplink signals RF analysis and calibration of the entire system.
(5) LTE terminal data application test
LTE mainly provides data services, so application testing is an important part of LTE research and development. After the R & S CMW500 is equipped with a data application unit and related test software, various data application tests can be performed. And because a graphical interface is provided, intuitive display results can be obtained through simple operations. So that users can easily verify the data performance of the terminal in the laboratory.
The CMW-PQA (Performance Quality Analyze) system is a set of platforms developed for operators based on the CMW500 protocol tester hardware platform that can simulate various complex wireless environments and perform various data application tests on terminals. The system composition is as follows: CMW500 is a system simulator; AMU200 is a baseband fading simulator; R & S CONTEST test software runs on the system controller, which can provide fully automated operation of test cases, powerful analysis functions of test reports, and summary of all aspects of reports Features. Provides an easy-to-use test plan, script-level R & D test application, and comprehensive test tools, which accelerate the progress of LTE R & D test.
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