Final Report - An Evaluation of Potential GPRS 900 … · These field levels would correspond to...

Authorised Use Only

Report prepared by: 1 30 December 2002 Telstra Research Laboratories GPRS/WCDMA EMI report

REPORT PREPARED BY:

EME Safety Research

Radio Networks Section

Final Report - An Evaluation of Potential GPRS 900 MHz and WCDMA 1900 MHz Interference to Consumer Electronics

Steve Iskra, Barry Thomas, Amico Carratelli and Mick Durrant

Version: 2.1 Date: 30 December 2002

Authorised Use Only


REPORT PREPARED BY:

EME Safety Research

Radio Networks Section


Steve Iskra, Barry Thomas, Amico Carratelli and Mick Durrant

Version: 2.1 Date: 30 December 2002

© The GSM Association 2002.

All rights reserved.

Use of this publication is permitted by the GSM Association only on the condition that:

1. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise;

2. No part of this publication may be used for any commercial purpose; and 3. No part of this publication may be given to any entity other than the entity to which the

GSM Association or its authorised representative has directly provided this publication without the prior consent of the GSM Association.

Approved by: Ray McKenzie, Project Manager, Telstra Research Laboratories. Address: 770 Blackburn Road, Clayton, VIC 3168, Australia [email protected] Approval Date: 30 December 2002

Authorised Use Only


EXECUTIVE SUMMARY Since the widespread introduction of mobile telephone services in the late 1980s, numerous studies have been conducted to assess the potential for radio frequency (RF) interference from mobile telephone handsets to consumer and business electronic equipment. Of particular interest has been the proliferation of handsets into sensitive environments such as health centres and hospitals, which utilise life and non life supporting medical equipment, and the influence of RF fields from handsets on body worn devices such as hearing aids. The main aim of this study was to compare the potential for interference to consumer electronics from RF fields radiated by GPRS 900 MHz and WCDMA 1900 MHz handsets (at their nominal in-band transmission frequencies). GPRS is a packet-based radio service that overlays additional control signalling on an existing GSM network and uses the same air interface as a GSM handset. It uses additional timeslots to obtain increased data rates which are necessary to support new mobile data and multimedia applications. In this study, a two-timeslot GPRS signal was used to simulate uplink transmission. Most GPRS and WCDMA (frequency division duplex (FDD) mode) handsets will have nominal peak output power levels of 2 W and 125 mW respectively. This work was conducted at Telstra’s Research Laboratories and sponsored by the GSM Association Environment Working Group Chaired by Brent Gerstle (SingTel Optus) and co-ordinated by Dr Jack Rowley, Director Environmental Affairs, GSM Association. A second phase of this work is being considered which would assess the interference potential of GPRS and WCDMA to medical equipment. The study was enhanced by additional testing with fields that are characteristic of radio transmissions from GSM 900/1800 MHz handsets, and 900/1800 MHz fields that comply with the requirements of the international immunity standard to RF fields, IEC 61000-4-3 [3]. This additional test data gives a sense of the overall interference impact that GPRS and WCDMA (FDD) handsets may have relative to current handset technologies and to the internationally recognised standard for radiated RF immunity. Four examples of consumer electronics were tested: a 40 cm colour television; a portable AM/FM/CD player; a portable AM/FM/SW radio; and a telephone (fixed line, analogue). Generally, each device exhibited some form of interference at one or all of the test field levels (1, 3, 10 and 30 V/m) with the exception of GSM 1800 MHz and WCDMA signals which caused no interference to any device at 1 V/m. The IEC 61000-4-3 specified test signal (80% amplitude modulated (AM) with 1 kHz sinewave) consistently produced more audio/visual interference than a GPRS or GSM type signal at the same carrier frequency and test field level. At the same test field level, audio/visual interference produced by WCDMA signals was generally lower than that produced by GPRS. The application of carrier amplitude power control to the WCDMA signal resulted in comparable, or in some instances, greater audio/visual interference than GPRS. The CD function of the AM/FM/CD player was equally sensitive to WCDMA single channel transmission (up to ~480kbps uplink data rate) and to GPRS, experiencing failure at 17.2 and 16 V/m respectively (playback of audio CD completely ceased). These field levels would correspond to distances of 0.09 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power. For 6 channel transmission (up to ~2 Mbps uplink data rate, with and without power control activated) the CD function was more susceptible to WCDMA (failed at 8.2 V/m) than to GPRS (failed at 16 V/m). These field levels would correspond to separation distances of 0.18 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power.

Authorised Use Only


The telephone failed to establish a connection to a recorded voice service at 20.3 V/m for GPRS (0.29 m from a handset operating at nominal peak output power). No telephone dialing failure was observed for WCDMA test signals at field levels up to 30 V/m. These results, when combined with the inherently lower maximum output power level of WCDMA, indicate that WCDMA will usually pose a lower risk of interference compared to GPRS for similar separation distances between handsets and common items of consumer electronics.

Authorised Use Only


CONTENTS 1. Introduction............................................................................................................6 2. Methodology..........................................................................................................7 3. Electromagnetic fields from handsets ...................................................................8 4. Test Conditions .....................................................................................................9

4.1 The radiated test field ...................................................................................9 4.2 The test signals...........................................................................................10 4.3 Measured average and peak power of test signals ....................................17 4.4 Recording of interference effects on equipment .........................................18 4.5 Equipment tested........................................................................................18

5. Results ................................................................................................................18

5.1 40 cm colour television ...............................................................................19 5.2 AM/FM/CD player .......................................................................................19 5.3 AM/FM/SW radio.........................................................................................20 5.4 Telephone (fixed line, analogue).................................................................20 5.5 Impact of test signal characteristics on interference...................................20 5.6 Summary.....................................................................................................21

6. Conclusions.........................................................................................................22 7. Acknowledgement ...............................................................................................23 8. References ..........................................................................................................24 Appendix 1 – Table 1: Portable 40 cm colour television ............................................25 – Table 2: Portable AM/FM/CD player ....................................................27 – Table 3: Portable AM/FM/SW radio .....................................................29 – Table 4: Telephone (fixed line, analogue)............................................31 Appendix 2 Images of visual interference on 40cm colour television 10 V/m test field strength ......................................................................33 Appendix 3 Frequency domain plots of GSM and GPRS TDMA characteristics.................................................................37

Notes Two supplements to this report are available, Supplement #1 and Supplement #2. Supplement #1 contains selected spectral plots and linked audio files of live recordings of interference heard on the AM/FM/SW radio. (size: ~11MB) Supplement #2 contains selected spectral plots of interference heard on the AM/FM/SW radio. (size: ~730KB)

Authorised Use Only



1. Introduction Since the widespread introduction of mobile telephone services in the 1980s, numerous studies have been conducted to assess the potential for radio frequency (RF) interference from mobile telephone handsets to consumer and business electronic equipment. Of particular interest has been the proliferation of handsets into environments such as health centres and hospitals, which utilise life and non life supporting medical equipment, and the influence of RF fields from handsets on body worn devices such as hearing aids. To control and minimise the likelihood of interference, protocols on the use of mobile technologies have been introduced in hospitals, and immunity standards have been developed for medical equipment [1] and devices such as hearing aids [2]. To date, a significant body of data has been collected which establishes the RF interference potential of existing analogue and digital mobile technologies to a range of electrical and electronic devices. However, new mobile technologies are constantly emerging, and it is the aim of this report to assess the potential for interference from GPRS (General Packet Radio Service) 900 MHz and wideband CDMA (WCDMA) 1900 MHz handsets to consumer electronic equipment. GPRS is a packet based radio service that overlays additional control signalling on an existing GSM network and uses the same air interface as a GSM handset. It uses additional timeslots to obtain increased data rates which are necessary to support new mobile data and multimedia applications. This report expands and extends on the results presented in the paper for the GSM Association, Interim Report – An Evaluation of Potential GPRS 900 MHz and WCDMA 1900 MHz Interference to Consumer Electronics, October 2002. It presents results of the first phase of work conducted at Telstra’s Research Laboratories and sponsored by the GSM Association Environment Working Group Chaired by Brent Gerstle (SingTel Optus) and co-ordinated by Dr Jack Rowley, Director Environmental Affairs, GSM Association. A second phase of this work is being considered which would assess the potential for interference from GPRS and WCDMA to medical equipment.

Authorised Use Only


2. Methodology

The evaluation of the potential for RF interference to consumer electronic equipment has been conducted by selecting a small but typical range of equipment and subjecting them to electromagnetic fields that are characteristic of radio transmissions from GPRS or WCDMA (frequency division duplex (FDD) mode) compliant handsets. The consumer electronic equipment used in this study consisted of a 40 cm colour television, portable AM/FM/CD player, portable AM/FM/SW radio and a fixed line, analogue telephone. The GPRS and WCDMA study has been enhanced by additional testing with fields that are characteristic of radio transmissions from GSM 900 and 1800 MHz handsets, and 900/1800 MHz fields that comply with the requirements of the international immunity standard to radio frequency fields, IEC 61000-4-3 [3]. This additional test data gives a sense of the overall interference impact that GPRS and WCDMA handsets may have relative to current handset technologies and to the internationally recognised standard for radiated RF immunity. The actual frequencies used for testing were 905.2 MHz (GSM/GPRS and 80% amplitude modulated (AM) with a 1kHz sinewave), 1810.4 MHz (GSM and 80% AM 1kHz sinewave) and 1920 MHz (WCDMA). In this report, these test frequencies are referred to as 900, 1800 or 1900 MHz respectively. The electromagnetic test field conditions were created in a semi-anechoic chamber using the method decribed in IEC 61000-4-3 [3], which establishes a ‘uniform’ plane wave environment in which the equipment is placed. The test field levels used during the study were 1, 3, 10 and 30 volts per metre (V/m). The response of equipment to the test fields was recorded in terms of the degradation in its performance using subjective and objective analysis. The equipment was subjected to vertically and horizontally polarised fields, and was rotated in the horizontal plane so that each of its sides was exposed to the test field. The worst case interference result was recorded (i.e., the equipment orientation and field polarisation that produced the most severe degradation at the test field level). Degradation to picture and/or audio quality was assessed using the following subjective grading scale:

• Imperceptible – interference is not visually or audibly detectable • Perceptible – faint audio/visual impact, not causing annoyance • Slightly annoying – viewer/listener may continue to listen/watch • Annoying – viewer/listener may persevere if content is important • Very annoying – difficult to watch/listen, viewer/listener unlikely to persevere • Unlistenable/unwatchable

Subjective assessment of picture quality and audio interference was performed using a range of program material. The grading of audio/visual interference was performed by three laboratory staff and the consensus view is shown in the tables of Appendix 1 (Tables 1 to 4). Appendix 2 contains photographs of interference on the television for a test level of 10 V/m. The subjective grading of audible interference was performed both during quiet passages of speech or music, and during sustained, louder periods of program material. In this way it is possible to gain an insight into the likely level of annoyance to listeners for various types of program material (eg., speech only, classical music, popular music, etc). Selected live recordings of interference heard on the AM/FM/SW radio are contained in the audio files linked to the report titled, Supplement #1 to Final Report – An Evaluation of Potential GPRS 900 MHz and WCDMA 1900 MHz Interference to Consumer Electronics.

Authorised Use Only


An objective interference effect was noted when the device either stopped working or lost one or more of its functions. For example, the AM/FM/CD player failed to operate in its CD mode and the telephone failed to establish a connection to a recorded voice service when subjected to particular field strengths and test signals.

3. Electromagnetic fields from handsets The free space field from a handset can be approximately determined by use of the dipole equation (1). If the output power of a handset is known, equation (1) can be used to estimate the far field as a function of distance ([3] Annex F and [4] Annex C).

dPkE = -- (1)

where E electric field in volts per metre P output power of the transmitter in watts d distance from the handset antenna in metres k a constant in the range 0.45 to 7, dependent on the antenna Equation (1) can be applied to the results of actual peak value field strength measurements from a GSM 900 handset reported in Table 1 of [5]. Using these results, a value of 4.2 is obtained for the factor k. This factor will however vary for different handsets and will be dependent on the efficiency and the gain of the handset antenna. Using Equation (1) and with k=4.2, the free space fields from GSM, GPRS and WCDMA handsets have been calculated based on their nominal peak output power level. Results are shown in plotted in Figure 1. The typical nominal peak output powers from handsets are: GPRS 900 MHz 2 W peak, average dependent on number of uplink timeslots GSM 900 MHz 2 W peak, 250 mW average GSM 1800 MHz 1 W peak, 125 mW average WCDMA (FDD) 1900 MHz 125 mW Handset transmit levels are controlled by the base station and are set to optimise the received signal levels and to conserve handset battery power. This generally results in transmit power levels that are significantly lower than the maximum permitted levels. In practice, the field created by a handset will be altered by reflections from walls, floors and ceilings, and by other objects in the immediate vicinity. This will result in a complex field pattern where the actual value of the field at any point in space may be more than double the free space calculation, or may be completely cancelled by reflections from nearby objects.

Authorised Use Only


Free space fields from handsets

1

10

100

0.1 1 10

distance (m)

Elec

tric

fiel

d (V

/m)

2 W1 W125 mW

Figure 1: Variation with distance of the free space fields from handsets for different transmit power levels calculated using Equation (1)

Table 1 below gives the distances from handsets, when operating at their nominal peak output power level, at which the peak fields are equal to the test field levels.

Power level (W) 1 V/m 3 V/m 10 V/m 30 V/m2 6 2 0.6 0.21 4.2 1.4 0.42 0.14

0.125 1.5 0.5 0.15 0.05

Test field levels

Distance from handset (m)

Table 1: Distance of peak fields from handsets

4. Test Conditions

4.1 The radiated test field

The test setup is based on the radiated immunity test method described in IEC 61000-4-3. The equipment under test (eg., consumer electronics) is placed in a RF screened, semi-anechoic chamber and a known, uniform field is established at the device. The electromagnetic field from a handset was simulated using a transmit antenna placed at a fixed height, and at a horizontal distance such that the equipment was in the far field region of the antenna. A log-periodic transmit antenna was used at 900 MHz and a waveguide transition at 1800/1900 MHz. The equipment was placed on a non-metallic, 0.9 m high turntable. The turntable structure consisted of a 0.6 m wooden table (rotatable in azimuth) on which a 0.3 m thick foam block was placed. The foam block was used to isolate the equipment from the wooden table to reduce the effect of reflections from the wooden table at higher frequencies.

Authorised Use Only


In accordance with IEC 61000-4-3, a uniform area of electric field strength was established at the equipment. The uniform area measured 0.5 m x 0.5 m and was a hypothetical vertical plane in which the field variations were acceptable small. The equipment had its face to be illuminated coincident with the uniform area. The unmodulated, continuous wave electric field at nine regularly spaced points in the area was measured with a Wandel & Goltermann EMR-300 electric field probe (100 kHz to 3 GHz, Type 8.2). The estimation of the measurement uncertainty associated with the uniform field is given in Table 2 and is based on the method described in the draft UKAS publication [6].

Sources of uncertainty Value (dB)

Field strength monitor1 2.75Power amp. drift 0.2Power amp. harmonics 0.3Field disturbance 0.5Measurement system repeatability 0.5

Total uncertainty 4.2

1 Includes frequency response, isotropicity and linearity

Table 2: The components of measurement uncertainty associated with establishing the uniform test field. The total measurement uncertainty is estimated to be ± 4.2 dB (95% confidence level) at 900/1800/1900 MHz using the method described in [6].

The unmodulated, root mean square values of the nominal test field levels chosen for the evaluation were 1, 3, 10 and 30 V/m. The field strength levels measured at the nine points varied between 0 dB and + 3.8 dB of the nominal test level for either vertical or horizontal polarisation (IEC 610004-3 requires that the variation be not more than 0 dB to +6 dB). For EMC immunity compliance testing, UKAS [6] recommends that the actual test field strength levels used during testing should be the nominal test level increased by an amount equal to the measurement uncertainty. The actual test field strength levels in this study were the nominal test levels and were not adjusted for measurement uncertainty. This does not impact on the outcomes of the study as its primary aim was to derive data on the relative potential for RF interference from handsets. It should be noted that the electromagnetic field at distances within a half wavelength from a handset (i.e., 0.17 m at 900 MHz) will be highly complex and non-uniform, unlike the plane wave test conditions created by the setup of IEC 61000-4-3. However, the advantage in adopting the approach of IEC61000-4-3 is that it provides test conditions that can be closely replicated in other laboratories and therefore allow inter-laboratory comparisons of interference results. 4.2 The test signals

A Rohde & Schwarz (R&S) signal generator (model SMIQ 03B) was used to produce the following test signals: GPRS (2 timeslots), GSM, WCDMA and 80% amplitude modulated carrier with a 1 kHz sinewave. Sinewave amplitude modulation is specified in IEC 61000-4-3 and is the basis of EMC immunity product standards such as CISPR 24 (IEC immunity standard for information technology equipment) [7].

Authorised Use Only


4.2.1 GSM/GPRS

In a GSM network, users are allocated carrier frequencies which are then divided in time using a time division multiple access (TDMA) scheme. The basic unit of time in this TDMA scheme is called a burst period (timeslot) which lasts for 0.577 ms. GPRS is a packet based radio service that overlays additional control signalling on an existing GSM network and uses the same air interface as a GSM handset. The essential difference in the air interface between GPRS and GSM that is of relevance to these tests is the use of additional timeslots by GPRS to obtain increased data rates and therefore support new mobile data and multimedia applications. Figure 2 below illustrates the differences. See Appendix 3 for frequency domain plots of GSM and GPRS TDMA characteristics.

Timeslot (TS)0 1 2 3 4 5 6 7 0 1 2

0 1 2 3 4 5 6 7 0 1 2

GSM

GPRSTS 0&4

4.615ms0.577ms

Figure 2: TDMA characteristics of GSM and GPRS (2 timeslots, 0 & 4). The pulse repetititon rate for GSM is 217 Hz and 434 Hz for GPRS TS 0 & 4.

The use of additional timeslots by GPRS changes the time-varying characteristics of the modulated signal and increases the time-averaged transmit power in direct proportion to the number of timeslots. These may influence the type and amount of audio and visual interference produced in consumer electronics.

Authorised Use Only


Figure 3 below shows the basic TDMA characteristics of a GSM signal produced by the signal generator. The plot was obtained with a HP 8546A EMI spectrum analyser in ZERO SPAN mode with 300 kHz resolution bandwidth and 100 kHz video bandwidth (carrier frequency 905.2 MHz). The pulse like nature of transmission is evident with the carrier turned on for 0.577 ms and the pulses repeated every 4.615 ms (4.613 ms measured).

Figure 3: TDMA characteristics of GSM signal. The carrier was modulated with random data using the GMSK (Gaussian Minimum Shift Keying) scheme.

Authorised Use Only


GPRS test signals were based on a network supporting handsets capable of transmitting two timeslots. Time slot (TS) combinations of TS 0 & 1, TS 0 & 2, TS 0 & 3 and TS 0 & 4 were used to simulate GPRS handset uplink transmission. Figure 4 below shows the envelope of the signal carrier for timeslot combination of 0 and 4 (GPRS TS 0 & 4). The signal generator produced a pulse of width 0.577 ms with a period of 2.29 ms. Initial testing revealed that the differences in interference outcomes obtained from the four TS combinations were slight, mainly exhibiting as shifts in demodulated audio tones and changes in the vertical spacing of horizontal interference bars on the television. The majority of GPRS testing was performed with the timeslot combinations of TS 0 & 2 and TS 0 & 4.

Figure 4: TDMA characteristics of GPRS (timeslots 0 and 4). The carrier was modulated with random data using the GMSK (Gaussian Minimum Shift Keying) scheme.

Authorised Use Only


4.2.2 WCDMA

The ITU first initiated the process of defining the standard for 3rd generation (3G) mobile systems1 and in 1998 the Third Generation Partnership Project (3GPP) was formed to continue with the work. WCDMA is a 3G mobile technology designed by 3GPP to provide global mobile access to real time and non-real time applications including voice, high speed data and multimedia applications. It is CDMA based but its spectral bandwidth has been increased to 5 MHz and it operates in the 1900-2000 MHz frequency band. Figure 5 below shows a WCDMA (FDD) signal produced by the signal generator. Network dimensioning and planning can support data rates of up to or more than 2 Mbps from handsets.

Figure 5: WCDMA (FDD) spectral bandwidth (curve shown for 15 ksps, uplink)

Two modes of operation for WCDMA have been specified – frequency division duplex (FDD) and time division duplex (TDD). FDD allocates frequency bands (uplink/downlink pairs) to users whilst in TDD the user is allocated timeslots. The signal generator can produce FDD physical channel layer signals to simulate either downlink (base station) or uplink (handset) operation based on version 3.4.1(Release ’99) of the WCDMA standard. The signal generator was not equipped for TDD operation. The WCDMA uplink direction uses QPSK-like in-phase (I) and quadrature phase (Q) multiplexing for user data and physical layer control information [8]. The control information is carried by the Dedicated Physical Control Channel (DPCCH) and the user data (along with higher layer information) is carried on one or more Dedicated Physical Data Channels (DPDCH). Each channel (DPDCH) has a maximum data rate of 960 kilo symbols per second (ksps) which is equivalent to 480 kbps (kilo bits per second) if the channel coding rate is ½. Up to six channels can be used by a handset resulting in a maximum uplink user data rate of 2 Mbps or more. 1 In the ITU, 3rd generation systems are known as International Mobile Telephony 2000 (IMT-2000). Within IMT-2000, several different air interfaces are defined based on either CDMA (e.g. WCDMA) or TDMA (e.g. EDGE) technology.

Authorised Use Only


To evaluate the impact of different data rates on the interference potential of WCDMA (FDD), the signal generator was configured in its handset (mobile station) mode to produce three signals: 1 channel of 15 ksps; 6 channels of 960 ksps; and 6 channels of 960 ksps with carrier amplitude power control. The plots in Figure 6 show the time instantaneous level of the carrier for 15 ksps and 6x960 ksps WCDMA transmission. When higher data rates are required, multiple channels are used which have the effect of increasing the peak-to-average level of the carrier.

Figure 6: Example time domain plot of WCDMA (FDD) 15 ksps and 6x960 ksps signals,and the unmodulated carrier. Note that the resolution bandwidth of the analyser (3 MHz) is less than the WCDMA signal (5 MHz) so that relative levels are indicative rather than absolute.

Authorised Use Only


The handset power is controlled by the base station in a closed loop power control, ensuring that the received power is at the correct and constant level. The steps of the power control is 1, 2 or 3 dB, and the rate of variation is 1500 Hz. Power control is implemented in handsets to compensate for signal variations due relative movement between the handset and the environment. The actual power variations will depend on the velocity of the user and the environment. The signal generator implements a simple form of power control as shown in Figure 7 (saw-tooth carrier amplitude). A 1 dB power step was chosen to represent actual situations. Note that power control imposes amplitude modulation on the carrier which in turn can be another source of interference to electronic equipment. The components of modulation will be 1500 Hz in the spectrum of the power variations (e.g. 1 dB steps), and a wider continuous spectrum at lower frequencies which represent the time varying channel power (e.g. saw-tooth function in Figure 7).

Figure 7: 6x960 ksps with power control applied (carrier level reducing in steps of 1 dB at rate of 1500 Hz). Plot also shows the level of the unmodulated carrier. The signal generator power control function is shown operating over the period of one radio frame (10 ms). In practice, handset power control can accommodate deeper fades (by choosing larger power control steps) that span over multiple radio frames.

Authorised Use Only


4.2.3 Sinewave amplitude modulation (sinewave AM)

Additional testing was performed with a signal that was 80% amplitude modulated with a 1kHz sinewave – see Figure 8 below. This allowed comparison of results obtained with GPRS and GSM test signals with the recommended test signal defined in the international immunity standard IEC 61000-4-3. Note that the peak amplitude of the AM signal is 80% higher than the carrier level. This contrasts with GPRS/GSM signals where the peak level is equal to the carrier level. Since the test fields are based on the level of the unmodulated carrier [3], it’s likely that the higher peak levels associated with the IEC test signal may give rise to stronger interference than for GPRS/GSM.

Figure 8: Time domain characteristics of an 80% amplitude modulated carrier with a 1 kHz sinewave.

4.3 Measured average and peak power of test signals

The peak and average power of test signals was either measured with an Agilent E4416A power meter and E9326A power sensor, or for WCDMA, the values were obtained from the information displayed by the signal generator. Table 3 below shows these values.

15 - 9601 6x960 2 6x960+PC

Average 0 dB +1.2 dB -6.3 dB -9.3 dB -0.1 dB -0.1 dB -0.1 dB

Peak 0 dB +5.1 dB 0 dB 0 dB +3.6 dB +6.8 dB +11.5 dB 1 Single channel: data rate between 15 and 960 ksps2 Six channels of 960 ksps

Power WCDMA (ksps)

Test signalUnmodulated carrier (reference level) 80% AM GPRS

(2 slots)GSM

Table 3: Measured average and peak power of test signals referenced to the unmodulated carrier. (+PC=with power control)

Authorised Use Only


4.4 Recording of interference effects on equipment

The effects of the applied test fields on the operation of the equipment under test was recorded and stored as a sound file (.wav format) for audio interference, digital photograph (.jpg/.bmp format) for visual interference, and written observations noting the subjective and/or objective interference effect. Audio interference was recorded with a SONY electret microphone (ECM-MS957) connected to a YAMAHA PCI audio card with the PC running Syntrillium Corporation’s “CoolEdit 2000” audio capture and analysis software. The immunity of the microphone at the test field levels was assessed to ensure that no measurement artifacts were introduced into the audio recordings during testing. The volume control setting on the equipment (radio, CD player and TV) being tested was adjusted so that the sound pressure level (SPL) did not exceed 80 dB (unweighted measurement) at 1 m from the equipment when measured with a RION NA-27 sound level meter. Spectral plots and selected live recordings of interference heard on the AM/FM/SW radio are contained in the audio files linked to the report titled, Supplement #1 to Final Report – An Evaluation of Potential GPRS 900 MHz and WCDMA 1900 MHz Interference to Consumer Electronics. Supplement #2 contains spectral plots of live recordings of interference heard on the AM/FM/SW radio. Visual interference observed on the TV screen was recorded using a Canon Powershot S20 digital camera. 4.5 Equipment tested

The following four items of consumer electronics were tested to obtain data on their immunity characteristics: a 40 cm colour television (PAL system B, no remote control function); a portable AM/FM/CD player; a portable AM/FM/SW radio; and a fixed line, analogue telephone. The physical dimensions (height x width x depth (m)) of the equipment were:

Height (m) Width (m) Depth (m)Colour TV 0.32 0.44 0.37AM/FM/CD player 0.15 0.5 0.25AM/FM/SW radio 0.18 0.3 0.08Telephone 0.07 0.2 0.22

5. Results The results of immunity testing are summarised in Appendices 1, 2 and in the Supplements to this report. Appendix 1 contains four tables which describe the observed interference effects for equipment tested. The observations of interference are expressed in subjective terms to describe the audio and visual impairments, and in objective terms to describe the failure of the telephone and the CD function in the AM/FM/CD player. A more detailed description and analysis of the audio interference for the AM/FM/SW portable radio at test field levels of 3 and 10 V/m are given in the Supplements to this report. A description of visual interference observed on the 40 cm colour television is given in Appendix 2 with accompanying photographs.

Authorised Use Only


In each of the tests described below, the polarisation of the test field and the relative position of the equipment in the horizontal plane (i.e., by rotation of the turntable) was changed in order to obtain a maximum interference effect. 5.1 40 cm colour television

The interference observed on the 40 cm colour television (Table 1 of Appendix 1 and photographs in Appendix 2 for a test field of 10 V/m) showed that 900 MHz sinewave AM and WCDMA 6x960 ksps (with power control) signals were similar in their interference ranking and produced the worst case results. The nature of the visual interference was different between 900 MHz sinewave AM and WCDMA signals. Interference produced by 900 MHz sinewave AM signals appeared as distinctive horizontal, evenly spaced bars, whilst WCDMA produced “wriggles” in vertical lines. WCDMA 6x960 ksps (without power control), GPRS/GSM 900 and 1800 MHz sinewave AM were equally less severe, with WCDMA 15 ksps and GSM 1800 producing the least amount of interference. 5.2 AM/FM/CD player

The AM/FM/CD player was tested in its radio and CD mode (Table 2 of Appendix 1). The radio was tuned to the FM station that exhibited the worst example of interference (access to AM broadcast signals in the shielded chamber was not readily available). Furthermore, preliminary testing outside of the shielded chamber with fields generated by GSM 900 and 1800 handsets revealed that the interference characteristics of the radio were independent of the broadcast band. This observation is consistent with previous experience and confirms that demodulation of the interfering signal is primarily occurring within the audio rather than RF stages of the radio. Therefore testing in the FM band provides an indication of the interference effect that would be observed in the AM broadcast band. The worst case interference was produced by the 900 MHz sinewave AM signal. The interference produced by the 900 MHz sinewave AM signal could be heard through the radio speaker as an audible 1 kHz tone. GPRS and GSM 900 were slightly less severe followed by 1800 MHz sinewave AM, WCDMA 6x960 ksps (with power control), GSM 1800, WCDMA 6x960 ksps (no power control) and WCDMA 15 ksps producing the least interference. The CD function was tested by playing an audio CD and observing the functioning of the player as the test field level was increased. Test fields in the range 8 to 17 V/m caused the CD player to completely stop functioning. Just prior to failure, the audio became very distorted with short, intermittent dropouts occurring. The CD player was most sensitive to a 1800 MHz sinewave AM test signal which caused failure at 7.1 V/m. The CD player was least sensitive to the 900 MHz test signals and to WCDMA 15 ksps. The CD function of the AM/FM/CD player was equally sensitive to WCDMA single channel transmission and to GPRS, experiencing failure at 17.2 and 16 V/m respectively (playback of audio CD completely ceased). These field levels would correspond to distances of 0.09 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power. For 6 channel transmission (up to ~2 Mbps uplink data rate, with and without power control activated) the CD function was more susceptible to WCDMA (failed at 8.2 V/m) than to GPRS (failed at 16 V/m). These field levels would correspond to separation distances of 0.18 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power.

Authorised Use Only


5.3 AM/FM/SW radio

Interference to the AM/FM/SW radio was observed with the radio tuned to the FM station that exhibited the worst example of interference (again, access to AM and SW broadcast signals in the shielded chamber was not readily available) (Table 3 of Appendix 1). Furthermore, preliminary testing outside of the shielded chamber with fields generated by GSM 900 and 1800 handsets revealed that the interference characteristics of the radio were independent of the broadcast band. This observation is consistent with previous experience and confirms that demodulation of the interfering signal is primarily occurring within the audio rather than RF stages of the radio. Therefore testing in the FM band provides an indication of the interference effect that would be observed in the AM or SW broadcast band. WCDMA 6x960 ksps (with power control) and 900 MHz sinewave AM produced the worst case audio interference (an audible 1kHz tone detected). Interference produced by the WCDMA test signal could be heard as an audible “buzz”. GPRS/GSM 900 and WCDMA 6x960 ksps signals were less interfering followed by WCDMA 15 ksps and 1800 MHz sinewave AM, with GSM 1800 producing the least amount of interference. 5.4 Telephone (fixed line, analogue)

Two modes of testing were performed on the telephone. In the first test mode, the telephone’s ‘REDIAL’ memory location was programmed with the telephone number of a recorded voice service (eg., time or weather). The ‘REDIAL’ button was pressed and connection to the service was established. The test field was then turned on and the audio interference noted (the call remained ‘up’). The second test mode involved dialing the recorded service (using the telephone’s ‘REDIAL’ function) whilst the test field was on. The results of tests are given in Table 4 of Appendix 1. It shows that for the first test mode, 900 MHz sinewave AM produced the worst case audible interference followed by GPRS/GSM 900, 1800 MHz sinewave AM, GSM 1800 and WCDMA 6x960 ksps (with power control). WCDMA 15 ksps and 6x960 ksps (no power control) produced the least amount of interference. In the second test mode, the telephone was unable to establish a connection to the recorded service when subjected to 900 MHz test fields. Dialing failure was observed at 11.7 V/m for 900 MHz sinewave AM, 20.3 V/m for GPRS and 24.8 V/m for GSM 900. No dialing failure was observed for 1800/1900 MHz fields at levels up to 30 V/m. The field levels 20.3 V/m and 24.8 V/m correspond to separation distances of 0.29 m and 0.25 m respectively from GPRS and GSM handsets operating at nominal peak output power. 5.5 Impact of test signal characteristics on interference

Observations of failure in the operation of the CD player and telephone provide some data on the influence of the peak versus the average value of a signal on failure threshold (i.e., field level at which failure occured). The comparison can be undertaken with some confidence since the tests required only that the field level be changed for different test signals whilst keeping all other parameters constant. Failure threshold levels at 900 MHz for the CD player and telephone are given in Appendix 1, and power levels for GPRS, GSM and 80% AM are given in Table 3. If the data is normalised to its respective 80% AM value, it can be plotted and a comparison made between the variation in the normalised peak and average values of GPRS, GSM and 80% AM signals, and the normalised failure threshold levels for the CD player and telephone. The results are plotted in Figure 9 below showing that the CD player and telephone are less susceptible to GPRS or GSM than to an 80% AM signal.

Authorised Use Only


-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

dB

(nor

mal

ised

to 8

0% A

M)

Ave pwr

Telephone

Pk pwr

CD player

GPRS GSM 80% AM

Figure 9: Plots of the normalised values of peak and average power, and CD player and telephone threshold levels (based on 900 MHz data).

The results also suggest that failure of the CD player and the telephone appears more closely related to the peak rather than the average value of a signal. The threshold failure result at 1800 MHz for the CD player shows that the player fails at 7.1 V/m for 80% AM and 9.4 V/m for GSM, representing a difference of 2.4 dB in threshold levels. Again, this indicates that the CD player is less susceptible to GSM than to 80% AM and that its failure is more closely related to the peak rather than average value of a signal. This is a first order analysis and the result is indicative only. No attempt has been made, for example, to examine the impact of the time domain characteristics of the modulating signal on the susceptibility of equipment. For instance, changing the modulation frequency of the 80% AM signal will not change its peak or average value but may cause a different response from electronic equipment. 5.6 Summary

The results are summarised as:

1. A two timeslot GPRS 900 MHz signal produced similar subjective rankings of audio/visual interference to that of a GSM 900 MHz signal for the same test field strength level;

2. The audio interference resulting from the use of GPRS timeslot 0 & 4 was slightly more

annoying than for timeslots 0 & 3, 0 & 2, 0 & 1 or GSM. The 0 & 4 combination produces 434 Hz tonal interference which appears slightly more audibly severe than a 217 Hz tone at the same acoustic level;

3. The audio/visual interference produced by sinewave AM signals appeared slightly more

annoying than that produced by GPRS or GSM type signals for the same carrier frequency and test field strength level;

4. At the same test field level, single channel WCDMA transmission (at uplink data rates from

~ 7.5 to 480 kbps) generally produced less audio/visual interference than GPRS. At uplink data rates approaching 2 Mbps and with carrier amplitude power control activated, WCDMA can produce similar and sometimes greater audio/visual interference than GPRS 900 MHz;

Authorised Use Only


5. The CD function of the AM/FM/CD player was equally sensitive to WCDMA single channel transmission and to GPRS, experiencing failure at 17.2 and 16 V/m respectively. For 6 channel transmission (up to 2 Mbps uplink data rate, with and without power control activated), the CD function was more sensitive to WCDMA (failed at 8.2 V/m) than to GPRS (failed at 16 V/m). The telephone failed to establish a connection to a voice recorded service at a field level of 20.3 V/m for GPRS. No telephone dialing failure was observed for WCDMA test signals at field levels up to 30 V/m;

6. The failure of the CD player and telephone (inability to establish a call) appeared to be

more closely related to the peak rather than the average value of the test signal;

7. These results, when combined with the inherently lower maximum output power level of WCDMA, indicate that WCDMA will usually pose a lower risk of interference compared to GPRS for similar separation distances between handsets and common items of consumer electronics.

6. Conclusions The main aim of this study was to compare the potential for interference to consumer electronics from RF fields radiated by GPRS 900 MHz and WCDMA 1900 MHz handsets (at their nominal in-band transmission frequencies). The study was enhanced by additional testing with fields that are characteristic of radio transmissions from GSM 900/1800 MHz handsets, and 900/1800 MHz fields that comply with the requirements of the international immunity standard to radio frequency fields, IEC 61000-4-3 [3]. This additional test data gives a sense of the overall interference impact that GPRS and WCDMA handsets may have relative to current handset technologies and to the internationally recognised standard for radiated RF immunity. Generally, all equipment tested exhibited some form of interference at one or all of the test field levels (1, 3, 10 and 30 V/m) with the exception of the GSM 1800 MHz and WCDMA signals which caused no interference to any device at 1 V/m. The IEC 61000-4-3 specified 80% amplitude modulated test signal generally produced greater audio/visual interference than a GPRS or GSM type signal at the same carrier frequency and test field strength level. The potential for interference from WCDMA was found to be related to the uplink data rate. Single channel transmission (at uplink data rates from ~ 7.5 to 480 kbps) produces significantly less audio/visual interference than GPRS at the same field level. Higher data rates require multiple channels which increase the modulation characteristics of the carrier and increase the interference potential of WCDMA - however its potential for interference is still generally lower than GPRS. WCDMA handset power control is another source of amplitude modulation and contributes significantly to an increase in interference. At uplink data rates approaching 2 Mbps and with carrier amplitude power control activated, WCDMA produced comparable, and sometimes greater, audio/visual interference than GPRS 900 MHz at the same field level. The CD function of the AM/FM/CD player was equally sensitive to WCDMA single channel transmission and to GPRS, experiencing failure at 17.2 and 16 V/m respectively (playback of audio CD completely ceased). These field levels would correspond to distances of 0.09 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power. For 6 channel transmission (up to ~2 Mbps uplink data rate, with and without power control activated) the CD function was more susceptible to WCDMA (failed at 8.2 V/m) than to GPRS (failed at 16 V/m). These field levels would correspond to separation distances of 0.18 m and 0.37 m respectively from WCDMA and GPRS handsets operating at their nominal peak output power.

Authorised Use Only


The telephone failed to establish a connection to a recorded voice service at 20.3 V/m for GPRS (0.29 m from a handset operating at nominal peak output power). No telephone dialing failure was observed for WCDMA test signals at field levels up to 30 V/m. These results, when combined with the inherently lower maximum output power level of WCDMA, indicate that WCDMA will usually pose a lower risk of interference compared to GPRS for similar separation distances between handsets and common items of consumer electronics. Therefore, guidelines for separation distances for consumer and other electronic devices derived from work with GSM-type signals are likely in the main to be conservative for WCDMA signals. Further work is being considered to extend this study to assess the effects of GPRS and WCDMA signals on medical electronics. However, an inital assessment based on studies of interference by GSM 900/1800 MHz and CDMA 800 MHz mobile phones with medical devices [9], suggests that existing guidelines will be conservative for the specific case of biomedical electronics.

7. Acknowledgement The authors thank Dr Anthony Saliba for providing assistance with the FFT function of the audio software, John Campbell and Fred Bullock for their guidance on the technical aspects of WCDMA technology, and to Ray McKenzie for his very helpful suggestions and comments.

Authorised Use Only


8. References [1] IEC 60601-1-2 (2001-09), Medical electrical equipment - Part 1-2: General requirements for safety - Collateral standard: Electromagnetic compatibility - Requirements and tests. [2] AS/NZS 1088.9:1995, Hearing aids – Immunity requirements and methods of measurement for hearing aids exposed to radiofrequency fields in the range 300kHz to 3 GHz, Standards Australia. [3] IEC 61000-4-3, EMC, Part 4: Testing and measurement techniques, Section 3: Radiated radio-frequency, electromagnetic field immunity test. [4] ANSI C63.18-1997, Recommended practice for an on-site, ad hoc test method for estimating radiated electromagnetic immunity of medical devices to specific RF transmitters. [5] K.J. Clifford, K. H. Joyner, D.B. Stroud, M. Wood, B. Ward and C. H. Fernandez, Mobile telephones interfere with medical electrical equipment, Australasian Physical & Engineering Sciences in Medicine (1994) Vol. 17, No. 1. [6] The Expression of Uncertainty in EMC Testing, United Kingdom Accreditation Service (UKAS) Publication LAB 34, Draft Edition 3, January 2002. [7] IEC CISPR 24:1997, Information technology equipment – Immunity characteristics – Limits and methods of measurement. [8] Holma, H. and Toskala, A., WCDMA for UMTS – Radio Access for Third Generation Mobile Communications, John Wiley & Sons, 2000 [9] S. Iskra, R. McKenzie and Z. Pleasants, Characterising the Electromagnetic Interference of Medical Equipment to GSM 900/1800 MHz and CDMA 800 MHz Mobile Telephones, Engineering and Physical Sciences in Medicine (EPSM) Conference, Rotorua, New Zealand 10th-14th November 2002

Authorised Use Only

Report prepared by Telstra Research Laboratories 25 30 December 2002 GPRS/WCDMA EMI report

Observed interference effects for the different types of modulation Field strength level GPRS 900 MHz WCDMA 1900 MHz GSM 900 MHz GSM 1800 MHz 900 MHz with 80% AM 1 kHz 1800 MHz with 80% AM 1 kHz

1 V/m Visual interference is imperceptible.

Audio interference is imperceptible.

15 ksps, 6x960 ksps and 6x960 ksps +PC: Visual and audio interference is imperceptible for all three test conditions.

Other functions remained unaffected.

Visual interference is imperceptible.






Visual interference is imperceptible. Audio interference is imperceptible.

3 V/m Visual interference is imperceptible.


15 ksps, 6x960 ksps and 6x960 ksps +PC: Visual and audio interference is imperceptible for all three test conditions.






Visual interference is perceptible.

Stationary, well-defined, horizontal, 5mm high, dark bands spaced 5mm apart vertically.

Audio interference perceptible during quiet passages.




For the 10 V/m data below refer to Appendix 2 for more detail of images of visual interference on 40 cm colour television

10 V/m Visual interference is perceptible and may be slightly annoying during some program material. Stationary, light bands ‘flicker’ through the picture.

Visual annoyance depends on program content (colours, movement).



15 ksps: Visual interference is perceptible, affecting vertical lines (small wriggles) more so than horizontal lines. Audio interference is imperceptible.

6x960 ksps: Visual interference is slightly annoying. Affects vertical lines more so than horizontal lines. Audio interference is imperceptible.

6x960 ksps + PC: Visual interference is annoying. Affects vertical lines more so than horizontal lines. Audio interference slightly annoying during quiet passages.


Visual interference is perceptible and may be slightly annoying during some program material. Lighter bands ‘flicker’ through the picture. (similar to GPRS.)

Structure of interference – stationary, well-defined, horizontal, 7mm high, lighter bands spaced 13mm apart that ‘flicker’ in the picture.






Visual interference is annoying.

Stationary, well-defined, horizontal, 5mm high, dark bands spaced 5mm apart vertically.

Audio interference annoying during speech and quieter passages. Perceptible during other audio content.

Visual interference is perceptible and may be slightly annoying during some program material (horizontal, dark bars ~5mm high and spaced ~5mm apart). Annoyance depends on program content (colours, movement).


30 V/m Visual interference is very annoying.

Stationary, light bands ‘flicker’ through the picture.



Audio interference very annoying during quiet passages.

15 ksps: Visual interference is annoying, affecting vertical lines more so than horizontal lines. Audio interference is imperceptible.

6x960 ksps: Visual interference is very annoying. Affects vertical lines more so than horizontal lines. Audio interference is imperceptible.

6x960 ksps + PC: Visual interference is very annoying. Affects vertical lines more so than horizontal lines. Audio interference annoying during quiet passages.


Visual interference is very annoying. Structure of interference – stationary, well-defined, horizontal, 7mm high, lighter bands spaced 13mm apart. Lighter bands ‘flicker’ through the picture.



Audio interference very annoying during quiet passages.

Visual interference is perceptible.


Visual interference is very annoying verging on being unwatchable. More annoying than GSM/GPRS.

Audio interference dominates – unlistenable.


Visual interference is slightly annoying (horizontal, dark bars ~5mm high and spaced ~5mm apart). Annoyance depends on program content (colours, movement).

Audio interference slightly annoying during quiet passages.

Appendix 1 – Table 1: Portable 40 cm colour television (mains powered, coaxial cable connection to aerial)

Authorised Use Only


THIS PAGE INTENTIONALLY BLANK

Authorised Use Only



1 V/m AM/FM radio – slightly annoying interference during quiet passages and imperceptible during loud passages. Increases with increasing volume setting.

CD – imperceptible interference. No loss of other functions.

AM/FM radio

15ksps No PC: imperceptible interference.

6x960ksps No PC: imperceptible interference.

6x960ksps+PC: imperceptible interference.

CD – imperceptible interference.

AM/FM radio – slightly annoying interference during quiet passages and imperceptible during loud passages. Increases with increasing volume setting.

CD – imperceptible interference. No loss of other functions.

(Essentially as for GPRS).

Audio interference is lower pitched than for AM 80% and GPRS. Slightly less annoying than GPRS.

AM/FM radio and CD – Imperceptible interference.

AM/FM radio – annoying audio interference during quiet passages and perceptible during louder passages.

CD – slightly annoying interference with interference independent of volume control setting (less annoying at high volume setting). No loss of other functions.

AM/FM radio – Perceptible only during quiet passages. Interference increases with increasing volume setting.

CD – imperceptible interference.

3 V/m AM/FM radio - very annoying interference for all types of program material. Increases with increasing volume setting.

CD – slightly annoying interference during quiet passages and imperceptible interference at high volume settings.

Interference independent of volume control setting. No loss of other functions.

AM/FM radio

15ksps No PC: Imperceptible interference.

6x960ksps No PC: Imperceptible interference.

6x960ksps+PC: Perceptible interference only during quiet passages.

CD – perceptible interference only during quiet passages.

AM/FM radio - very annoying interference for all types of program material. Increases with increasing volume setting.

CD – slightly annoying interference during quiet passages and imperceptible interference at high volume settings.

Interference independent of volume control setting. No loss of other functions.



AM/FM radio – Perceptible interference only during quiet passages and imperceptible during loud passages. Independent of volume control.

CD – as for radio.

AM/FM radio – very annoying interference for all types of program material. Interference increases with increasing volume setting.

CD – annoying interference in quieter passages, interference independent of volume control setting ( interference is perceptible at high volume setting). No loss of other functions.

AM/FM radio – annoying audio interference during quiet passages and imperceptible during louder passages. Interference increases with increasing volume setting.

CD – slightly annoying interference with interference independent of volume control setting (less annoying at high volume setting). No loss of other functions.

10 V/m AM/FM radio – unlistenable for all types of program material. Increases with increasing volume setting.

CD – very annoying interference during quiet passages and annoying at high volume settings. Interference independent of volume control setting. No loss of other functions.

AM/FM radio – Interference increases with increasing volume setting.

15ksps No PC: imperceptible interference.

6x960ksps No PC: Perceptible interference (‘white noise’) during quiet passages, imperceptible interference during loud passages.

6x960ksps+PC: annoying interference during quiet passages (low frequency ‘buzz’) and imperceptible during louder passages.

AM/FM radio – unlistenable for all types of program material. Increases with increasing volume setting.

CD – very annoying interference during quiet passages and annoying at high volume settings. Interference independent of volume control setting. No loss of other functions.



AM/FM radio – Annoying interference during quiet passages and imperceptible interference during loud passages. Independent of volume control.

CD – Annoying interference during quiet passages. Imperceptible interference during loud passages

AM/FM radio – unlistenable. Interference dominates over program material.

CD – annoying interference independent of volume control setting (less annoying at high volume setting). No loss of other functions.

AM/FM radio – very annoying interference for all types of program material. Interference increases with increasing volume setting.

CD – annoying interference in quieter passages. Interference independent of volume control setting (interference is perceptible at high volume setting). No loss of other functions.

8-17 V/m CD – stopped playing at 16 V/m

Severe audio distortion near point of failure..

CD – stopped playing at: 17.2 V/m for 15 ksps 8.6 V/m for 6x969 ksps 8.2 V/m for 6x960 ksps+PC

Severe audio distortion near point of failure.

CD – stopped playing at 16.6 V/m.








30 V/m No test conducted. No test conducted. No test conducted. No test conducted. No test conducted. No test conducted.

Appendix 1 – Table 2: Portable AM/FM/CD player (mains powered during testing)

Authorised Use Only



Authorised Use Only



1 V/m Perceptible during quiet passages.

15ksps No PC: imperceptible during quiet passages.

6x960ksps No PC: imperceptible during quiet passages.

6x960ksps+PC: imperceptible during quiet passages.

Perceptible during quiet passages.

(Essentially as for GPRS.)

Imperceptible during quiet passages.

Perceptible during quiet passages.

Imperceptible.

For the 3 V/m and 10 V/m data below refer to the Supplements to this report for more detail on the test conditions as well as spectral plots and 10 second audio samples of the program material

3 V/m

Test condition No. 1 Slightly annoying interference during loud passages. Annoying interference during quiet passages.

Test condition No. 2 Slightly annoying interference during loud passages. Annoying interference during quiet passages. i.e., TS0&4 “buzz” 2 x 217Hz tone.

Test condition No. 3 15ksps No PC: Perceptible interference only during quiet passages.

Test condition No. 4 6x960ksps No PC: Slightly annoying interference for loud music passages. (Sample 1 of 2) Annoying interference during quieter music passages and speech. (Sample 2 of 2)

Test condition No. 5 6x960ksps+PC: Very annoying interference for any program material.


(Essentially as for GPRS TS 0 +2.)

Test condition No. 7 Imperceptible interference during quiet passages.


(Overall slightly more annoying than GSM/GPRS due to the 1 kHz tone.)

Test condition No. 9 Perceptible interference only during quiet passages.

10 V/m

Test condition No. 1 and Test condition No. 2

Unlistenable – interference obliterates program material with an overall marked increase in audio level.

Test condition No. 3 15ksps: Annoying interference, ‘scratchy’ in nature, program material clearly audible.

Test condition No. 4 6x960ksps No PC: Annoying interference (as above), but slightly lower overall audio level.

Test condition No. 5 6x960ksps+PC: Unlistenable – interference obliterates program material with an overall marked decrease in audio level.

Test condition No. 6 Unlistenable – interference obliterates program material with an overall marked increase in audio level.


Test condition No. 7 Slightly annoying interference during loud music passages. (Sample 1 of 2) Annoying interference during quieter music passages and speech. (Sample 2 of 2)

Test condition No. 8 Unlistenable – interference dominates over audio program material.

Test condition No. 9 Annoying interference during loud passages. Very annoying interference during quiet passages.

30 V/m Unlistenable – interference obliterates program material with an overall marked increase in audio level.

15ksps: Interference is annoying, ‘scratchy’ in nature, program material clearly audible.

6x960ksps+PC: Unlistenable – interference obliterates program material with an overall marked decrease in audio level.

Unlistenable – interference obliterates program material with an overall marked increase in audio level.


Annoying interference during loud passages.

Very annoying interference during quiet passages.

Unlistenable – interference dominates over audio program.

Not tested.

Appendix 1 – Table 3: Portable AM/FM/SW radio (mains powered during testing)

Authorised Use Only



Authorised Use Only



1 V/m (Just) perceptible interference. 15 ksps – imperceptible interference.

6x960 ksps – imperceptible interference.

6x960 ksps+PC – imperceptible interference.

(Just) perceptible interference. Imperceptible interference. Slightly annoying interference. Imperceptible interference.

3 V/m Annoying interference. 15 ksps – imperceptible interference.


6x960 ksps+PC – perceptible interference.

(line quality masks ‘white’ noise-like interference).

Annoying interference. Perceptible interference Slightly annoying interference at times.

Very annoying interference. Slightly annoying interference.

10 V/m Very annoying interference. Distorts voice.

15 ksps – imperceptible interference.


6x960 ksps+PC – annoying interference.


Very annoying interference. Distorts voice.

Annoying interference. Fails to establish call.

Unlistenable if call in progress when interference turned on (program material barely audible).

Very annoying interference.

11- 25 V/m Telephone fails to establish a call at 20.3 V/m.

Telephone fails to establish a call at 24.8 V/m

Telephone fails to establish a call at 11.7 V/m

30 V/m Fails to establish call when test field on.

Unlistenable if call in progress when interference turned on (program material barely audible compared with interference).

15 ksps – perceptible interference.

6x960 ksps:– perceptible interference.

6x960 ksps+PC:– very annoying interference.


Fails to establish call when test field on.

Unlistenable if call in progress when test field turned on (program material barely audible compared with interference).

Very annoying interference. Fails to establish call when test field on.

Unlistenable if call in progress when interference turned on (program material completely suppressed – only interference remains.

Verging on being unlistenable.

NOTE: The analogue telephone was connected to dialup Recorded Voice Announcements and the interference rankings above were heard across speech and silence.

Appendix 1 – Table 4: Telephone (fixed line, analogue)

Authorised Use Only



Authorised Use Only


Appendix 2

Images of visual interference on 40cm colour television

10 V/m test field strength

900 MHz, 80% amplitude modulated carrier with a 1kHz sinewave

Interference is annoying. 1800 MHz, 80% amplitude modulated carrier with a 1kHz sinewave

Enlargement

dark bands

Visual interference is perceptible and may be slightly annoying for some program material.

Stationary horizontal bands

Authorised Use Only


WCDMA 15 ksps

Visual interference may generally be imperceptible. However, interference can be perceptible in program material (such as cartoons) that contains clear, sharply defined lines. WCDMA 6x960 ksps

Visual interference may be slightly annoying, particularly when program content contains sharply defined lines.

Small ‘wriggles’ in vertical line

‘wriggles’ in lines

Authorised Use Only


WCDMA 6x960 ksps with power control (1dB steps)

Visual interference may be annoying when program content contains sharply defined lines. Application of WCDMA power control has increased the interference effect. GSM 900 MHz Interference is perceptible and may be slightly annoying depending on program content.

Enlargement

Lines become ‘torn’ and ‘smudgy’

Authorised Use Only


GSM 1800 MHz Visual interference is imperceptible. GPRS 900 MHz, uplink timeslots 0 & 4

Enlargement

bands

Interference is perceptible and may be slightly annoying depending on program content. Timeslot combinations simply alter the spacing between interference bands but do not change the visual intensity of the bands.

Authorised Use Only


Appendix 3

Frequency domain plots of GSM and GPRS TDMA characteristics GSM

GPRS (timeslots 0 & 1)

Authorised Use Only




Authorised Use Only



Date post:	30-Jul-2018
Category:	Documents
Upload:	truongthuan
View:	214 times
Download:	0 times

Final Report - An Evaluation of Potential GPRS 900 … · These field levels would correspond to...

Documents