As a 3g standard for autonomous intellectual property rights in china, testing has received considerable attention in the td-scdma commercial process. R & s (rod and schwartz) has been following the development of td-scdma in china. Several years ago, the industry pioneered the td-scdma test solution and is currently the rare instrumentator that offers a comprehensive td-scdma radiofrequency test programme。
Based on different processes from research and development to production, the td-scdma test can be divided into four stages:
1. Test evaluation of modules and devices;
2. Integration of modules into the system and validation testing of the entire system;
3. Production tests at bulk production;
4. Network planning, deployment and optimization testing。
At different stages, testing methods, focus and attention vary: the device tests focus primarily on parameters indicators associated with the device; the system tests focus on the performance of the whole machine; the production tests focus on speed, repetition and stability; and the network planning and optimization would like the network to function properly and improve its quality. To meet the needs of the different stages of testing, r&s provides the corresponding solutions for each stage of testing。
Module and device testing
In order to ensure that the final product is tested for strict consistency, it is necessary first to ensure that the base band and radio frequency (rf) device circuits meet stricter requirements. In addition to traditional linear and non-linear analyses using vector network analysers (e. G., s parameters, 1 db compression points, 3rd-order intersections, etc.), during the test phase of the device and module, a vector signal source plus a spectrum analyser or vector signal analyser is required for the analysis of the time, frequency, code and modem domains of the measure under the td-scdma signal conditions (e. G., ccdf, acp, evm, etc.). The vector signal source smj100a and spectrum spectrometer fsu (or fsp) of r&s can achieve these tests. The following is an example of multi-load wave power release and direct drop station (rru) testing。
The test items for the td-scdma base station and the direct site testing of major evaluations include:
:: faith power;
:: power-to-time relationship (pvt) (up and down templates);
:: adjacent channel leakage ratio (aclr) (single and multi-load waves);
:: multi-load wave power;
:: spectrum fragmentation templates;
:: spectrum launch template (sem);
* error vector range (evm)。
During the td-scdma r & d test, the need for pvt, multi-load aclr and various trigger signals was relatively high and r&s could fully meet the requirements。
Fsu and fsp use special methods for pvt (power time template) testing to achieve a large range of 112 db switches. This allowed fsu and fsp to easily test the td-scdma base at pvt with maximum launch power。
The td-scdma base station will require a maximum test of six carrier aclr, and smj100a will produce a very desirable signal, while the fsu/p also provides an adequate range of measurements. This ensures that the aclr tested was not caused by the test instrument. Fsu six wave aclr can reach 66db and fsp six wave aclr can reach 61db。
3. Due to the timing properties of td-scdma, multiple trigger signals are required for testing, provided to analytical instruments and to be tested, and smu has flexible and convenient trigger signal settings that can generate various trigger signals。
4. For testing as a modem indicator, the error vector range evm is important for direct drop stations and performance tests, as it directly reflects signal distortion and malformations caused by the non-linearity of amplifiers. The td-scdma selection, embedded in the fsu/p, can test not only the power and spectrum of the td signal, but also its evm directly, which greatly facilitates the installation and direct station testing。
5. The introduction of a 16qam high-level mode in td-hsdpa places greater demands on the linearity of power and direct stations. In addition to the need to test evm-typed indicators, the symbol constellation is also a necessary test. Figure 1 provides an example of testing indicators for constellation maps and modems。
Research and development and consistency testing of base stations and terminals
3gp 25. 142 (base station) and 34. 122 (end) radio frequency consistency test specifications define test requirements for transmitters, receiver characteristics and systemic capabilities. The td-scdma lcr base station/end was tested in accordance with the requirements of 1. 28 mcps tdd of the code. These norms are those used in research and development and consistency testing. At that stage, tests of the equipment being tested were often very rigorous to remove potential deficiencies. Research and development tests are extremely demanding for instrument functions, dynamic ranges, precision, etc。
R&s provided r & d test solutions for smu200a + fsq + sma + nrp. Smu200a may incorporate a two-way independent source of signals, which can be used to generate useful signals, and a normatively defined range of jamming signals (continuous wave or modem signal interference), which will enable the performance of two signals sources. Moreover, smu200a can produce various decay simulations and awgns of the normative requirements, so that a smu200a can meet the requirements of regulation for signal sources. The fsq spectrometer model has the best dynamic range in the same product, which is very important in the conduct of the required proliferation tests and aclr tests. The fsq vector signal analysis model, on the other hand, allows for iq domain analysis of signals and allows for location and analysis of malfunctions at the research and development stage. Sma is a high-performance analogue signal source that can be used to receive traffic characterization tests. Power nrp is primarily used for precision power testing。
Audio performance testing is important for the td-scdma/gsm two-module terminals. User satisfaction is directly affected by the good and bad performance of the audio. 3gp specifications ts 26. 132 and ts 26. 131, as well as national tender yd/t 1538-2006, detail the technical requirements and test methods for audio performance of digital mobile terminals. Three main components are required for the build-up of audio testing systems: system simulators (e. G. R&s cmu200), audio analysers (e. G. R&s upv or upl) and artificial mouth-to-mouth ears. This is a certification-level testing platform, and in china, upv and upl have also been used by authoritative testing agencies to test the audio consistency of the td-scdma/gsm two-modules。
Production tests for base stations and terminals
The production tests for the td-scdma terminal are usually divided into two steps: the former makes radio frequency adjustments to the receiver and transmitter of the terminal; and the latter, after completion of the complete assembly, tests whether the performance indicators for the complete machine meet the required requirements. Because of the high output of the terminals, test equipment is required to be fast, accurate, test consistent, failure rate and maintenance costs。
There is an urgent need for a fast td-scdma production tester for the industry, which is currently in the production phase of the td-scdma terminal. The r&s high-speed amplifier cmw500, which provides a very high speed, accuracy and testing capability, supports a number of mobile communication standards, including td-scdma, and meets this industry demand。
Cmw500 is based on a new testing platform, which is introduced from modern testing concepts and needs. As modern mobile phones become more complex, increasing new communication standards and frequency allocations have led to increased testing demand, which has significantly increased the cost of testing for end producers. Therefore, in order to cope with the increase in test time and costs associated with multiple standards and frequency bands, in addition to maximizing the speed of instrument testing, it is necessary to have completely new testing methods and concepts。
In terms of radio frequency performance and support for future wireless communications, the cmw 500 frequency may be assigned to 3. 3 ghz or 6 ghz, with a medium bandwidth of 40 mhz analyser and 70 mhz signal source, respectively. Future trends in wireless technology have been fully taken into account in the design of the instrument, allowing users to achieve minimum test costs and low-risk investment. Cmw 500 sets up a powerful radio frequency analyser and signal source, as well as an entirely new test concept, which ensures the highest test performance, the smallest volume and the lowest amount of effort。
As noted earlier, innovative testing concepts are needed to further improve the speed of testing. R&s has developed r&s smart calibration (r&s smart association) testing techniques for chip and wireless equipment producers. Cmw500 can support this innovative testing technique, as well as derived rapid radio frequency calibration tests such as the radio frequency calibration method based on rx/tx power scanning (power sweep). This allows the end-line radio frequency calibration time to be accelerated 10 times faster than the traditional method。
In addition, for end-production, if the pass rate of the first test is maximized, errors can be reduced and thus the overall test time reduced. The improvement in the rate of passivity depends on the optimization of the entire production process, in which the precision and consistency of the instrument is crucial. R&s cmw500 is excellent in absolute accuracy, test repetitivity and linearity, which ensures a high rate of first-time test pass。
For the td-scdma base station and the direct drop site, r&s recommended fsp+smj00a. This is a quick and economical test solution. The k50/k51 selection, which is embedded in smj, produces a standard signal of different levels and frequencies, which can be used both to test the transmitter radio frequency module and to perform receiver sensitivity ber/bler measurements. Smj has excellent radio frequency performance and very fast frequency/level stabilization time, allowing for rapid and accurate testing. Spectrometer fsp, in conjunction with the built-in k76 selection, can test indicators for launch modules such as power, pvt, error vector range (evm), frequency error and spectrum characteristics. The test is fast and accurate. Smjs and fsps provide easy access to base and direct site testing systems。
Network deployment and planning, optimization testing
The road monitoring system is an important test equipment for this phase. The tsmq/tsmu/tsml series of r&s is a high-performance, full-frequency, multi-standard wireless analyser and a core equipment in the road monitoring system. It is independent of testing mobile phones for measuring and analysing wireless signals. The high speed of continuous wave (cw) tests allows multi-frequency, high-mobility tests to be performed and provide important data for network planning and optimization, meeting li's law. R&s' romes overlay testing software is a common routing platform that connects to test mobile phones, gsps, tsmx, and achieves routing of various communication standards。
The electromagnetic environment must also be considered when the network is deployed. Along with the rapid development of wireless communications, public attention to the level of electromagnetic radiation in the environment has increased. In order to carry out the measurement of the environmental electromagnetic field, rod and schwartz introduced the portable environmental electromagnetic field test system r&s ts-emf: it consists of field detectors and spectrum spectrometers (fsh or fsl), with external testing software r&s rfex, which facilitates accurate measurements and statistical assessments of the electromagnetic field in space areas, as shown in figure 2。
An accurate and reliable assessment of the radiation effects of a base station requires not only comprehensive short- and long-term measurements of its electromagnetic field, but also measurements at a larger regional scale. To date, there are two methods of measuring the environmental electromagnetic effects: broadband measurements with a full field probe or frequency selective measurements with directional antennas. The ts-emf of r&s combines the advantages of two measurement methods: frequency selective measurements with a full-way antenna at 30m ~3ghz. The test software r&s rfex is dedicated to environmentally compatible electromagnetic applications that facilitate accurate measurements and statistical assessments of electromagnetic fields in densely populated areas and allow for long-term monitoring of certain locations (e. G. Schools) for several days or weeks, giving scientific and accurate assessments。
Concluding remarks
As a new technical standard, td-scdma suffers from a slight lack of technological maturity and commercial experience, and therefore extensive testing is an essential prerequisite for its successful commercialization. In addition to radio frequency testing, testing in areas such as operations and connectivity is important。
