R&S®TS8980 scalable test system family

¸CMW500PTwith ¸CONTEST

¸CMW500PT + ¸AMU200A+ fading in realtime

¸TS8980S+ interferers

¸TS8980FTA+ spurious, TX intermod.and blocking test cases

¸TS8980IB+ self-calibration for

max. RF accuracy

Protocol conformance / R&D

Performance quality analysis (PQA)

RRM conformance

RF precompliance

Partial network-operator-specific RF test coverage Network-operator-specific RF conformance tests(NetOP package required)

RF conformance

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R&S®TS8980 test system family for LTE and WCDMA/HSPA+HSPA+ is inexorably conquering the market, and LTE is on the very threshold of commencing certification.

This confronts manufacturers and network operators with a challenging need for tests. Rohde&Schwarz has,

of course, provided test equipment in good time: the scalable R&S®TS8980 RF conformance test systems.

These systems incorporate the new R&S®CONTEST user interface and seamlessly integrate the radio

resource management (RRM) tests.

Scalable from lab applications to conformity testsThe R&S®TS8980 RF conformance test systems are scalable, and a suitable system is available for every task (FIG 1). An R&S®CMW500PT wideband radio communication tester and the R&S®CONTEST user interface can be used as the start-ing point, and the RF test functionality can then be expanded step by step up to the R&S®TS8980FTA (box on page 3) for full RF user equipment certification.

FIG 2 shows the block diagram of the R&S®TS8980FTA (FTA: full type approval). The R&S®CMW500PT simulates a base station for LTE or WCDMA/HSPA+. It is equipped with two independent RF channels so that MIMO test cases and diver-sity tests can also be carried out. The R&S®FSQ26 is a high-quality signal and spectrum analyzer for inband tests as well as for measuring unwanted harmonics and spurious emissions from user equipment. The R&S®SMU200A and

FIG 1  The R&S®TS8980 test system family provides leeway for customized expansions: from the R&S®CMW500PT protocol tester with R&S®CONTEST 

for development tasks in the lab, to the R&S®TS8980FTA for full RF user equipment certification.

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R&S®TS8980FTA RF conformance test system

¸SMU200Avector signal generator

¸SMF100Awideband signal gen.

Ethernet

Control PC with ¸CONTEST

¸FSQ26signal and

spectrum analyzer

¸CMW500signaling unit

A̧MU200Afading simulator

¸SFE100broadcast tester

¸SFE100broadcast tester

TV extens.combiner

Widebandsignal switching

andconditioning unit

2 × 2

¸NRP-Zpower sensor

Inbandsignal switching

andconditioning unit

2 × 2

¸NGMO2power supply

Rubidiumfrequency standard

DUT

USB

¸OSP open switchand control platform

MSCU(configurable)

R&S®SMF100A baseband and RF signal sources generate the adjacent channel and other interfering signals for receiver and performance characterization. The channel emulators inte-grated in the R&S®AMU200A baseband signal generator and fading simulator simulate the channel characteristics.

The test systems of the R&S®TS8980 family test user equip-ment in the 400 MHz to 6 GHz carrier frequency ranges. The inband signal switching and conditioning unit (ISSCU) includes the relays, directional couplers, combiners and amplifiers required for the inband tests. The modular signal switching and conditioning units (MSCU) are 19" plug-ins that can contain filters for up to six frequency ranges defined by the Global Certification Forum (GCF) or the PCS Type Certifi-cation Review Board (PTCRB). They filter outgoing signals and signals to be analyzed. The MSCU plug-ins are designed to be independent of standards and can therefore also be used for HSPA+ and WCDMA applications in addition to LTE in the specified band.

A Rubidium frequency standard as the frequency reference and an intelligent power sensor from the R&S®NRP-Z fam-ily for the path calibration complete the measurement system. To simulate TV interferers, the system can be expanded with two R&S®SFE100 broadcast testers and the R&S®OSP open switch and control platform.

FIG 2  Block diagram of the R&S®TS8980FTA test system. Orange: additional equipment for simulating TV interferers.

The R&S®TS8980FTA test system contains the wideband signal switching and conditioning unit (WSSCU), the MSCU filter units and the R&S®SMF100A microwave signal gen-erator. This means it includes all measuring equipment for spurious and blocking tests as well as for assessing inter-modulation susceptibility. If these seven especially demand-ing test cases for LTE-FDD and LTE-TDD can be omitted, the R&S®TS8980IB (inband) test system can be used wich cov-ers more than 90 % of the test cases and involves signifi-cantly less hardware.

Further savings result from the R&S®TS8980S configura-tions tailored to R&D and PQA applications or from the R&S®CMW500PT featuring the new R&S®CONTEST user interface. No test cases are currently validated on these two systems.

The TS 36.521 3GPP standard, which describes the confor-mance tests for LTE, contains transmitter, receiver, perfor-mance and channel state report tests in Part 1, Chap. 6-9. A simple software expansion enables the R&S®TS8980 test system to also support radio resource management tests in accordance with TS 36.521 Part 3. Rohde&Schwarz also offers the RRM test cases from TS 36.521-3 as a solution that is independent of the RF test system – an important advantage in certification applications with high throughput.

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User-adaptable GCF/PTCRB test casesAt the time of printing, Chapter 9 in TS 36.521-1 is not yet complete. However, the validation of currently around 50 LTE RF test cases already began with CAG#22 in April 2010. RF certification for LTE user equipment is scheduled to commence at the start of 2011.

In addition to the specification-compliant process, the R&S®TS8980 also allows numerous input parameters of the LTE RF tests to be modified in accordance with the TS 36.521-1 3GPP test specification. The optional 

performance evaluation mode (PEM) makes this easier through the configuration of additional test steps directly in the (otherwise unaltered) certification test plan with just a few clicks of the mouse. In the optional R&D mode, it is also pos-sible to compile fully user-defined test cases on the basis of the supplied test methods.

Test cases that comply with 3GPP Rel-7 for HSPA+ user equipment in accordance with TS 34.121-1 are generated and validated on the R&S®TS8980 test systems – in parallel to LTE. These test systems are designed for the broadest possible

Key features of the new R&S®TS8980 test system family ❙ Widest possible scope of test cases for (pre)certification, for acceptance by net-work operators, for development labs and for regression in performance quality analysis

❙ Utmost measurement accuracy, even outside the conformance test cases

❙ Fast test runs, since the frequency of a new connection setup is minimized

❙ Very rapid switchover of RMCs and fading profiles

❙ Output of the test run time for each test case and for the entire test sequence

❙ Calculation of measurement accuracy for each test case in realtime

❙ R&S®CONTEST user interface ❙ Generation of user-defined test cases without additional programming

❙ Wide range of logging and analysis tools ❙ RF and RRM tests on the same hardware ❙ Existing R&S®TS8950W and R&S®TS8970 test systems can be converted to R&S®TS8980IB or R&S®TS8980FTA

❙ RF acceptance tests of various network opera-tors already exist as ready-made test cases

FIG 3  The R&S®TS8980FTA test system.

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FIG 4  The new R&S®CONTEST user interface.

coverage of HSPA+ and LTE test cases. For the time being, however, full coverage of WCDMA tests in accordance with Rel-99 to Rel-6 and of GSM test cases is only provided by the R&S®TS8950* conformance test system.

Network-operator-specific RF acceptance tests In addition to R&D, PQA and certification applications, accep-tance tests of large network operators are also becoming increasingly important for user equipment manufacturers. The R&S®TS8980 family provides ideal support in this respect, since the test plans were developed and verified in good time in close cooperation with a number of network opera-tors. Expansions for Verizon Wireless, AT&T and NTT DoCoMo (Telec) are currently available. FIG 2 shows an example of such a “NetOP” expansion that consists of two R&S®SFE100 broadcast testers for simulating ATSC and MediaFLO™ inter-ferers in the FDD13 band (700 MHz) in the Verizon Wireless network.

New R&S®CONTEST user interfaceA sequence (test plan) can be composed easily and quickly with the new R&S®CONTEST user interface: The test cases are simply dragged from the “Applications” window (on the left in FIG 4) into the “Test Plan” (right) with the mouse. This allows test cases from the conformance, R&D and NetOp applications to be sequenced in any desired order. A test plan can contain test cases from different standards such as LTE combined with WCDMA in a single sequence. Free combinability with RRM test cases in accordance with TS 36.521-3 is also planned.

The central window area in FIG 4 (“General Statements”) pro-vides commands for flow control, which are also simply inserted into the test plan using drag-and-drop. Several loops (“Loop” commands) are automatically generated for confor-mance test plans. Parameters that change slowly, such as the climatic chamber temperature, are inserted into the outer loops; parameters that change rapidly over time, such as the test frequency, are inserted into the inner loops. This dramat-ically increases the speed of test plan execution, since the number of time-consuming connection setups is reduced to a minimum.

* R&S®TS8950W WCDMA test system: Conformance test system for WCDMA. News from Rohde&Schwarz (2003) No. 178, pp. 14–16.

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FIG 5  Result graphics are created in realtime.

Analysis – online and offlineA test plan runs completely automatically. The anticipated total run time appears on the user interface before the start. During the run time, result graphics are created in realtime (FIG 5). After completion, they are stored in the report along with the text output. The report is created in HTML and can therefore be easily processed and converted into other for-mats. The graphics are also stored in JPG format after the end of the test run. The optional summary report is available after the end of a test run to complement the reports for each test case. In addition to an overview of the tests that were run and their results (PASS / INCONCLUSIVE / FAIL), the sum-mary report also includes hyperlinks to the test case reports, allowing users to branch directly and rapidly from the sum-mary report to the problem analysis.

The summary report is stored in XML format. It is adapted to the display program (e.g. Internet Explorer) based on sample templates that provide various degrees of detail. Users can edit these sample templates, e.g. to insert company logos into the report.

SummaryWith the new R&S®TS8980 test system family, Rohde&Schwarz paves the way for its customers, from the design of broadband wireless user equipment for LTE and WCDMA / HSPA+ to its fastest possible market launch. Due to their extremely high configuration flexibility and scalabil-ity, the test systems can be easily and quickly adapted to indi-vidual requirements. The test system family has been greeted with a very positive response from user equipment manufac-turers and certification labs.

Ralph Gibbemeyer

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