Presentation is loading. Please wait.

Presentation is loading. Please wait.

A d v a n c i n g w i r e l e s s t e s t Testing the Radio Performance of TETRA Terminals and Base Stations 4 th TETRA World Congress, Nice, 10 th December.

Similar presentations


Presentation on theme: "A d v a n c i n g w i r e l e s s t e s t Testing the Radio Performance of TETRA Terminals and Base Stations 4 th TETRA World Congress, Nice, 10 th December."— Presentation transcript:

1 a d v a n c i n g w i r e l e s s t e s t Testing the Radio Performance of TETRA Terminals and Base Stations 4 th TETRA World Congress, Nice, 10 th December 2001 Clive Rodmell Graham Stevens Senior Principal Engineer Product Manager

2 a d v a n c i n g w i r e l e s s t e s t 2 Overview of Presentation Understanding the impact of TETRA equipment performance on network operation Examining the new radio performance requirements of TETRA compared with analogue systems Analyzing the new challenges of testing TETRA equipment Evaluating test solutions for TETRA

3 a d v a n c i n g w i r e l e s s t e s t 3 The Impact of TETRA Equipment Performance... Understanding the impact of TETRA equipment performance on network operation Examining the new radio performance requirements of TETRA compared with analogue systems Analyzing the new challenges of testing TETRA equipment Evaluating test solutions for TETRA

4 a d v a n c i n g w i r e l e s s t e s t 4 TETRA is a RADIO network The radio link is the weakest link in the chain TETRA Network Operation Validation Proves the theory of network operation Manufacture Ensures individual equipment meet requirements initially Service Ensures individual equipment continues to meet requirements Conformance Proves the equipment design

5 a d v a n c i n g w i r e l e s s t e s t 5 Requirements for TETRA Network Integrity Correct BS transmit power level for coverage required Correct MS transmit power level as dictated by network Adequate sensitivity of MS and BS receivers Minimal interference caused to other users Minimal susceptibility to signals from other users Protection and maintenance of antennas and cables

6 a d v a n c i n g w i r e l e s s t e s t 6 The Impact of Poor Radio Performance Interference Excess power Reduced coverage Inadequate power Inadequate sensitivity Retransmissions Increased response times Reduced system capacity Poorer quality speech and video Failure to set up or maintain a call

7 a d v a n c i n g w i r e l e s s t e s t 7 New Radio Performance Requirements of TETRA... Understanding the impact of TETRA equipment performance on network operation Examining the new radio performance requirements of TETRA compared with analogue systems Analyzing the new challenges of testing TETRA equipment Evaluating test solutions for TETRA

8 a d v a n c i n g w i r e l e s s t e s t 8 TETRA compared with Analogue systems TETRA is a TDMA system (Time Division Multiple Access) TETRA is a DIGITAL system TETRA is a CONTROLLED LINK system

9 a d v a n c i n g w i r e l e s s t e s t Scrambled Bits 14 Bits Training Sequence 16 Bits 216 Scrambled Bits 14.2 ms Typical slot ms TDMA Frame Air Interface - TDMA Illustrated 1.02 s Multiframe s 3 Hyperframe

10 a d v a n c i n g w i r e l e s s t e s t 10 TETRA Power Profile Mask Transmitted power of a TDMA signal is BURSTY Power is transmitted in short bursts t 1 t dBc +6 dB 0 dBc +3 dB of nominal power 1.5 dB - + t 2 (time intervals not to scale)

11 a d v a n c i n g w i r e l e s s t e s t 11 Performance Requirements of a TDMA System Power ramp up / down according to mask Controlled profile to minimize interference Adjacent channel power due to switching Timing of bursts must be correct Power is attenuated between bursts Non-constant envelope Active Timeslot Power +1 Time dBc (MS) Consequences of a bursty signal

12 a d v a n c i n g w i r e l e s s t e s t 12 Performance Requirements of the Digital System All transmitted signals are binary data Successful transmission and recovery of 1s and 0s Requirements for Parametric measurements change Vector accuracy replaces distortion for Tx measurements Vector Diagrams Bit Error Rate (BER) replaces SINAD for Rx sensitivity RF Loopback Synchronization of MS to BS frequency and timing

13 a d v a n c i n g w i r e l e s s t e s t 13 Vector Accuracy 0.3R - Peak Vector Error (limit 30 %) 0.05R - Residual Carrier Leak Removed (limit 5 %) RMS Vector Error limit 10 % R Q I

14 a d v a n c i n g w i r e l e s s t e s t 14 Measuring sensitivity requires the use of BER measurements Measuring Rx Sensitivity Test Port T1 Signal Generator Radio Under Test Bit Error Rate meter RF MS BS Static-112 dBm-115 dBm Faded-106 dBm-103 dBm

15 a d v a n c i n g w i r e l e s s t e s t 15 UUT Test Equipment Tx Rx Returned patterns Test patterns RF Loop Back Test Configuration Optimized for manufacturing and service testing Eliminates need for proprietary interfaces and test modes

16 a d v a n c i n g w i r e l e s s t e s t 16 TETRA radios operate at defined power ratings MS power level is variable in defined steps A TETRA radio determines optimum power level itself This requires measurement by MS of received signal strength MS determines level and quality of signals from serving and neighboring BS 30 mW Performance required of a Controlled Radio Link MS power is optimized Reduces interference Increases battery life

17 a d v a n c i n g w i r e l e s s t e s t 17 TETRAs co-existence with Analogue TETRA system is very highly specified to avoid interference with analogue systems In terms of both close to carrier and far from carrier emission The following may cause interference to analogue radio channels Adjacent Channel Power (ACP) TETRA Power Ramping (Switching) TETRA Transmitter Linearization TETRA Transmitter Intermodulation This has presented some CHALLENGES in TESTING

18 a d v a n c i n g w i r e l e s s t e s t 18 TETRAs co-existence with Analogue Analogue signals may cause interference in the TETRA Receiver Blocking Spurious Response Intermodulation Response Measures performance in the presence of two strong interfering signals Reference Sensitivity Wanted Channel 200kHz -47 dBm +3 dB T1T3 400kHz T2

19 a d v a n c i n g w i r e l e s s t e s t 19 New Challenges of Testing TETRA Equipment Understanding the impact of TETRA equipment performance on network operation Examining the new radio performance requirements of TETRA compared with analogue systems Analyzing the new challenges of testing TETRA equipment Evaluating test solutions for TETRA

20 a d v a n c i n g w i r e l e s s t e s t 20 Conventional Test Methods Unsuitable for TETRA Most conventional analogue test methods can not be used Traditional power meter does not work for burst power Traditional frequency meter does not work for DQPSK modulation 1 kHz distortion meter does not work for digital transmitter 1 kHz SINAD meter does not work for digital receiver Conventional swept spectrum analyzer is inadequate New Innovative methods are required

21 a d v a n c i n g w i r e l e s s t e s t 21 New Testing Challenges for TETRA Tx Most TETRA Tx measurements Must be TETRA filtered >80 dB Require high dynamic range Must be time-aligned

22 a d v a n c i n g w i r e l e s s t e s t 22 T3 T2 T1 New Testing Challenges for TETRA Rx Key RF Rx measurements: Sensitivity Selectivity Intermodulation Response Spurious Response Blocking These tests require the use of: TETRA signal generator (T1) One or two interfering signals TETRA interferer (T2) CW interferer (T3) Test system performance must be considerably better than the equipment under test Minimize influence on results

23 a d v a n c i n g w i r e l e s s t e s t 23 Evaluating Test Solutions for TETRA Understanding the impact of TETRA equipment performance on network operation Examining the new radio performance requirements of TETRA compared with analogue systems Analyzing the new challenges of testing TETRA equipment Evaluating test solutions for TETRA

24 a d v a n c i n g w i r e l e s s t e s t 24 Interoperability Testing Validation R&D concentrate on a particular aspect Manufacture Fast and accurate Service Test functionality, easily Different stages of testing require different equipment All testing requires specialized TETRA test equipment Test Solutions for TETRA Conformance Comprehensive testing

25 a d v a n c i n g w i r e l e s s t e s t 25 Important Issues for Conformance Testing Comprehensive radio equipment testing RF Parametric Protocol tests Purpose is to prove to Users and Operators that radio equipment conforms to specification Static Dynamic Using propagation simulator and Fading models Automated system

26 a d v a n c i n g w i r e l e s s t e s t 26 Important Issues for Manufacturing All radio equipment is tested to a degree Level of test is dependent on: PASSED Test 1 passed Test 2 passed Test 3 passed Test 4 passed Test 5 passed Test 6 passed Design repeatability Manufacturing process Speed of testing required Remote control of test equipment Quality Control Level of testing reduces as TETRA technology matures

27 a d v a n c i n g w i r e l e s s t e s t 27 Test Solutions for TETRA Equipment Manufacture TETRA specific modulation analyzer for Tx measurements High dynamic range Accurate implementation of TETRA filter Speed of test important T1 or similar signals required for receiver testing Dynamic (faded) receiver tests usually too time consuming

28 a d v a n c i n g w i r e l e s s t e s t 28 TETRA Installation and Servicing Important issues Ease of use of test equipment Subset of measurements required for manufacturing Test solution RF Loopback eliminates special test connectors Functional tests (registration, call set-up) Give confidence that TETRA radio is dependable

29 a d v a n c i n g w i r e l e s s t e s t 29 IFRs Support for TETRA Support the TETRA standard Actively involved in development of standards ETSI EN Radio Conformance Specification TETRA Interoperability Profile (TIP) Supply equipment for radio conformance testing Supply equipment for interoperability testing Participate in the Interoperability trials Working with the radio manufacturers to provide Production Test solutions Ensuring effective test equipment for service is available

30 a d v a n c i n g w i r e l e s s t e s t 30 and Finally..... Testing Ensures Trust Reliability Availability


Download ppt "A d v a n c i n g w i r e l e s s t e s t Testing the Radio Performance of TETRA Terminals and Base Stations 4 th TETRA World Congress, Nice, 10 th December."

Similar presentations


Ads by Google