b21c - d11-1 - dvb-h network planning

WP3 – NETWORK & CHANNELS

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DELIVERABLE D11-PART 1

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DVB-H NETWORK PLANNING

B21C – CELTIC project CP4-004

WP3 – Network & Channels

Deliverable D11 – 1

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Participants in project B21C are:

Åbo Akademi University (ABO) - Finland Agilent - Belgium Alcatel-Lucent - France BBC - UK DiBcom- France Digita OY - Finland Elektrobit Corporation – Finland Ecole Nationale Supérieure des Télécommunications (ENST) - France Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V. (FhG) – Germany France Telecom R&D – France Hispasat - Spain Institut d’Electronique et de télécommunications de Rennes (IETR) - France Mier Comunicaciones S.A. Nokia Corporation - Finland NXP Semiconductors -france Radio Televisione Italiana (RAI) - Italy Retevisión (Abertis Telecom group) - Spain Rohde & Schwarz - Germany Robotiker - Spain SIDSA – Spain Sony – UK Space Hellas - Greece Tampere University of Technology (TUT) TeamCast - France Télédiffusion de France (TDF) - France Telefonica – Spain Spectracom (formerly Temex Sync) – France Technical University Braunschweig, Institut für Nachrichtentechnik - Germany Teracom – Sweden Thomson Grass Valley (formerly Thales Broadcast & Multimedia) - France Turku University of Applied Science (TUAS) – Finland Universitat ramon Lull – Spain University of Bologna – Italy University of Surrey – UK University of Turku - Finland

B21C – Broadcast for the 21st Century - Project coordinator: Gérard Faria TeamCast

CELTIC published project result

2007 CELTIC participants in project B21C

Disclaimer

This document contains material, which is copyright of certain CELTIC PARTICIPANTS and may not be reproduced or copied without permission. The information contained in this document is the proprietary confidential information of certain CELTIC PARTICIPANTS and may not be disclosed except in accordance with the regulations agreed in the Project Consortium Agreement (PCA). The commercial use of any information in this document may require a licence from the proprietor of that information. Neither the PARTICIPANTS nor the CELTIC Initiative warrant that the information contained in this document is capable of use, or that use of the information is free from risk, and accept no liability for loss or damage suffered by any person using the information.




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EEXXEECCUUTTIIVVEE SSUUMMMMAARRYY

DVB-H networks are much denser than conventional radio and TV-networks. They consist of several stations operating on the same frequency (single frequency networks, SFN). Therefore, new network planning methods, taking into account the summation of several SFN signals, are required. TF 303 has concentrated efforts to analyse existing DVB-H networks field measurements in order to improve the planning tools by comparing the measured and predicted field strengths.

In this document, section 2 describes the channel models adopted for the analysis and section 3 details the link budget for different reception cases (roof top, portable outdoor, portable indoor and mobile handheld). The link budget is required in order to specify the minimum field strength required at the reception point and the minimum median equivalent field strength to be used in planning.

Section 4 presents the propagation model and the coverage prediction method that have been used to estimate the coverage area of SFN networks.

Section 5 presents the results of field measurements carried out in 2007 in four places of Finland: Helsinki, Turku, Tampere and Oulu, in order to verify the accuracy of the coverage prediction.

The results of the comparison between measurements and predictions are analysed in section 6. It has been observed that:

The biggest differences are observed in regions close to the transmitting stations (field strength > 90 dBµV/m), but this is not important in practice since there is always a good service in these areas.

The highest standard deviations between measurements and predictions are in general observed for field strength values below 70 dBµV/m, but a good service cannot be ensured in these areas and prediction errors are not so important.

The range of interest of field strength values for network planning is between 70 and 90 dBµV/m. In this range, measurements fit fairly well to the predictions (the standard deviation is in the order of 4 - 5 dB).

The accuracy of the planning methods can be improved if some terms in the link budget, like lower field strength location variations, were better known. Therefore, a complementary study presented in section 7 has been performed in order to analyse these variations in SFN networks. Some measurements have been carried out in different urban, sub-urban and rural zones of Finland in order to determine the location variation of the field strength as a function of the distance between points or “pixel size”. It has then been observed that the location variation of dense SFN networks is much smaller than normally used in link budgets (5.5 dB) and that the so-called “SFN gain” (the reduction of the number of transmitters required to cover a given area using SFN compared to a multiple frequency network) is mainly due to lower field strength location variations.

Section 8 presents the results of the compatibility study between DVB-H and DVB-T systems. The performance of several low-cost DVB-T receivers has been measured in the presence of a DVB-H interfering signal. It has been shown that:

In the case of normal DVB-T reception, receivers are (more than) compliant with protection ratios specified in the baseline receiver specification IEC 62216-1.

In the case of DVB-T receiver overloading, protection ratio defined in IEC 62216-1 could be applied as a function of interfering signal level and frequency.

A major recommendation would be not to use DVB-T adjacent channels to plan DVB-H.




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Most of the DVB-T receivers have a sufficient performance to reject DVB-H. Only in some local cases, the receiver distance to DVB-H transmitter might be too small. This can be avoided by careful network design and ad-hoc solutions.

In section 9, the impact on the network architecture of the frequency band choice (VHF: 174–230 MHz, UHF IV/V: 470–862 MHz and L–band: 1452–1492 MHz) is studied, resulting in the following comments:

VHF band is hardly compatible with handheld terminals, due to the physical constraint on the reception antenna size.

Theoretical network planning studies show that the use of L-band will have a strong impact on network architecture, as a denser network than in UHF band IV/V will be required to get the same coverage and use cases, including indoor reception. The number of sites may be up to three times higher, due to propagation characteristics in this band, and reduced guard intervals to enable mobility, thus resulting in a costlier network.

UHF is the best trade-off between network cost, mobility, building penetration losses and antenna integration in the handheld terminal. However, this band is already heavily used and the introduction of mobile TV in UHF may require spectrum optimisation or reallocation.

Many European countries which have launched or are planning to launch mobile TV services have selected DVB-H and the UHF band IV/V restricted to channels 21-55 (474 – 750 MHz), using one of the layers from the Geneva 06 agreement. In most cases the current coverage is limited by the heavy use of this spectrum, but it is planned to be gradually extended as the switch-off of analogue services will progress until 2011.




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LLIISSTT OOFF AAUUTTHHOORRSS // DDOOCCUUMMEENNTT HHIISSTTOORRYY

Version Date Author(s) Comment

v0 01.12.2007 Esko Huuhka …

v1 21.12.2007 Esko Huuhka …

v2 12.06.2009 Esko Huuhka

v2 12.06.2009 Pierre Bretillon

v3 01.10.2009 Esko Huuhka




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TTAABBLLEE OOFF CCOONNTTEENNTT

1 Introduction .................................................................... 8

2 Channel Models ............................................................... 9

3 Link Budget ................................................................... 10

3.1 SFN gain ...................................................................................... 12

4 Planning Methods ......................................................... 13

4.1 Propagation Models ..................................................................... 13

4.2 DVB-H Coverage Prediction ......................................................... 14

5 Field Measurements ...................................................... 16

5.1 Measuring system ....................................................................... 16

5.2 Analyzing Method ........................................................................ 16

6 Comparisons between measurements and predictions 19

6.1 Conclusions ................................................................................. 25

7 Location variations ........................................................ 26

7.1 Conclusions ................................................................................. 38

8 DVB-T/H Compatibility ................................................. 41

8.1 Measurements ............................................................................. 41

8.2 Impact on Network Planning ...................................................... 46

8.3 Conclusions ................................................................................. 48

9 Consideration of spectrum other than UHF for DVB-H . 49

9.1 Introduction ................................................................................ 49

9.2 Spectrum status for DVB-H services ........................................... 49

9.3 Frequency band impact on system and network architecture .... 50 9.3.1 Impact of VHF ............................................................................................... 50 9.3.2 Impact of L-Band .......................................................................................... 50

9.4 Status on frequency bands used for DVB-H in several European countries ..................................................................................... 53

9.4.1 Finland ......................................................................................................... 53 9.4.2 France .......................................................................................................... 53 9.4.3 Germany ....................................................................................................... 53 9.4.4 Italy ............................................................................................................. 53




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9.4.5 Spain ............................................................................................................ 54

9.5 Conclusions ................................................................................. 54




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11 IINNTTRROODDUUCCTTIIOONN

DVB-H networks are much denser than conventional radio and TV-networks. The networks consist of several stations operating on the same SFN-frequency. Therefore new network planning methods which can sum the SFN-signals are required

IDVB-H is a broadcast technology, where the same signal is distributed to any number of terminals located in the coverage area of the SFN network. There is no need for reducing the cell radius in order to increase the number of connected users, as conversely needed in cellular networks (e.g. GSM, UMTS).

However, DVB-H handheld terminals are normally mobile phones (actually, DVB-H is already one of the options available on mobile phones), and this implies requirements in terms of required field strength.

As a consequence, planning a DVB-H network has to deal with new issues, and requires a different approach with respect to DVB-T. High power DVB-T transmitter has typically coverage area radius 50 – 60 kilometres for fixed antenna reception but for DVB-H reception the coverage area radius with the same power is only 10 – 15 km. Therefore for the DVB-H area coverage large number of SFN transmitters is required.

The Wing TV Project has already examined the various issues relevant to DVB-H networks, providing tools for network operators and defining a channel model and a set of parameters for DVB-H link budget calculations.

In B21C project WP3 TF303 has concentrated to analyse existing DVB-H networks field measurements and tried to improve the planning tools by comparing the measured and predicted field strengths.




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22 CCHHAANNNNEELL MMOODDEELLSS

The propagation channels between transmitter(s) and reception point must be modelled in -order to specify the required S/N-values. In DVB-H three channels, portable indoor (PI) portable outdoor (PO) and mobile, has been defined. The channel models are based on channel measurements

The main parameters to be resolved from measured data are number of taps (with appropriate power cut threshold), power delay profile (PDP) -exponent (when it is appropriate), maximum excess delay, rms (root mean square) delay spread. These parameters will help to understand the physical behaviour of the radio channel. Spatial dispersion (i.e. measurements were conducted with SISO system) was not explicitly included in the treatment.

Derivation of the tapped delay line models is based on average power delay profiles for each selected channel type. The individual multipath components are extracted from the measurements using 30 dB power cut threshold. The PDPs were determined from the impulse response data by dividing the data into smaller sets (time-wise) to satisfy the stationary requirement. Then the average PDP of each set was calculated and finally the PDPs from several measurements (from the same environment) were averaged. Accurate 24 tap channel models were formed by visual inspection from these averaged PDPs. One criterion in the selection process was the frequency correlation of the taps: the selected taps should have a low frequency correlation on the bandwidth of the receiver.

Reduction to 12 taps is accomplished by using localized delay and power estimation. The delay axis is divided into groups or sub-regions allocated by the power concentration and the total number of required taps. The more local power density the PDP has, the more densely the sub-regions are located, hence providing enhanced accuracy for the modelling. For each segment, mean delay value is calculated corresponding to tap delay. Special care has been used to maintain possible SFN-structure of the profile. Consequently, the power of the tap is found by summing all the multipath powers within segment. Finally power normalization is made, i.e., the largest tap has value of 0 dB.

The verification of PI and PO channel models is in deliverable B21C – D08 Part 1 – PIPO Channel Verification.




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33 LLIINNKK BBUUDDGGEETT

The link budget is required for planning to specify the minimum field strength required in the reception point and the minimum median equivalent field strength to be used in planning.

The minimum field strength and minimum median equivalent field strength values calculated using the following equations:

Pn = F + 10 log (k T0 B)

Ps min = C/N + Pn

Aa = G + 10 log (1.64 2/4 )

φmin = Ps min – Aa + Lf

Emin = φmin + 120 + 10 log (120 )

= φmin + 145.8

Emed = Emin + Pmmn + Cl for roof top level fixed reception

Emed = Emin + Pmmn + Cl + Lh for portable outdoor and mobile reception

Emed = Emin + Pmmn + Cl + Lh + Lb for portable indoor and mobile hand-held reception

Cl = µ σt

σt = 22mb

where:

Pn : receiver noise input power (dBW)

F : receiver noise figure (dB)

k : Boltzmann’s constant (k = 1.38 10–23 (J/K))

T0 : absolute temperature (T0 = 290 (K))

B : receiver noise bandwidth (B = 7.61 106 (Hz))

Ps min : minimum receiver input power (dBW)

C/N : RF S/N at the receiver input required by the system (dB)

Aa : effective antenna aperture (dBm2)

G : antenna gain related to half dipole (dBd)

: wavelength of the signal (m)

φmin : minimum pfd at receiving place (dB(W/m2))

Lf : feeder loss (dB)

Emin : equivalent minimum field strength at receiving place (dB( V/m))

Emed : minimum median equivalent field strength, planning value (dB( V/m))

Pmmn : allowance for man-made noise (dB)




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Lh : height loss (reception point at 1.5 m above ground level) (dB)

Lb : building or vehicle entry loss (dB)

Cl : location correction factor (dB)

σt : Total standard deviation (dB)

σm : standard deviation macro-scale (dB)

σb : standard deviation building entry loss (dB)

µ : distribution factor being 0.52 for 70%, 1.28 for 90%, 1.64 for 95% and 2.33 for 99%.

The height loss Lh can be included in the prediction method and it is not included in the link budget. In practice it is useful to make an excel table to use the above formulas (Table 1.). Note that the minimum median equivalent field strength for planning is given at the height of 1.5 meters from the ground level, the height loss calculation is included in the prediction method.

Example of Link Budget, 16QAM 1/2 MPE-FEC 5/6 (8.29 or 9.21 Mb/s)

Parameter Abbr Unit Urban PI

Rural PI

Urban PO Mobile Train

Frequency Fr MHz 474 746 554 610 610

Noise floor PN=kTB dBm -105 -105 -105 -105 -105

Rx Noise Figure F dBm 5 5 5 5 5

C/N C/N dB 13 13 13 17 17

Min Rx input power Ps min dBm -87 -87 -87 -83 -83

Rx antenna gain Grx dBd -12 -7 -10 -9 -9

Antenna aperture Aa dBm2 -25 -24 -24 -24 -24

Min. Field Strength Emin dBµV/m 53 52 53 57 57

Location correction Cl dB 9 9 9 9 9

Building loss Lb dB 15 8 0 6 20

E in planning at 1.5 m Emed dBµV/m 77 69 62 72 86

Table 1, Example of DVB-H Link Budget

The noise figure and antenna gain depends on the terminals. Therefore it would be very important to get some more information of these values and B21C project should recommend some values for planning. The C/N values are coming from channel models.

The location correction value is historically based on standard deviation of 5.5 dB. It is probably the combination of field strength location variation and prediction error. In Chapter 6 the prediction accuracy and in Chapter 7 the location variation is dealt in detail. The location correction factor used for DVB-H planning should be derived from location variation in the “pixels” used and the field strength prediction accuracy as proposed in conclusions in chapter 7.1.

The vehicle entry loss of 6 dB is based on mobile phone measurements and it is probably quite good value. The building entry losses have very high deviation (4 – 35 dB) depending on the type of building. A single




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value can not be used in all cases, the value should be chosen by using best knowledge.

If the planning method calculates field strengths at the height of roof top level the height loss must be added in the link budget calculation.

33..11 SSFFNN GGAAIINN The “SFN gain” is the reduction of number of transmitters to cover a given area using synchronized transmitters compared to the number of independent MFN transmitters. Depending on the network topology, this transmitter savings may be carefully translated into an average increase of coverage.

In Chapter 7. it is shown that the SFN-gain is due to lower field strength location variation in SFN networks compared to MFN networks. It is not considered in the link budget as separate term but it is taken into account as lower location variation.




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44 PPLLAANNNNIINNGG MMEETTHHOODDSS

DVB-H planning methods are used to estimate the coverage area of an SFN network. The DVB-H coverage planning methods normally consist of propagation prediction model and method to combine the predicted field strengths and to show the results on the map. The input parameters are always the network site information (site coordinates, antenna height and radiation pattern and ERP) and the required minimum median equivalent field strength (link budget).

44..11 PPRROOPPAAGGAATTIIOONN MMOODDEELLSS To implement DVB-H network, propagation models are necessary to determine propagation characteristics for any arbitrary installation. The predictions are required for a proper coverage planning, the determination of multipath effects as well as for interference, which are the basis for the high-level network planning process.

The great complexity of the propagation mechanism makes difficult to have accurate methods that can be adapted to all the different possible environments. The results provided by the propagation methods must be considered as estimations that could be corrected in certain circumstances. Many propagation models can be tuned based on measurements campaigns in the coverage area. A tuning algorithm finds the parameters of the calculation model that better adjust to the measurements.

The mechanisms behind electromagnetic wave propagation are diverse, but can generally be attributed to reflection, diffraction and scattering. The accuracy of the propagation model depends on available cartography and its resolution (pixel size). Normally the terrain height and clutter databases are used.

The widely used path loss model for signal strength prediction and simulation in macro cellular environments is the Hata-Okumura model. This model is valid for the 500-1500 MHz frequency range, receiver distances greater than 1 km from the base station, and base station antenna heights greater than 30 m. There exists an elaboration on the Hata-Okumura model that extends the frequency range up to 2000 MHz.

CRC-model

The propagation prediction method used in Digita is based on Canadian Research Centre CRC-PREDICT® program. This VHF/UHF Propagation Prediction Program is used for estimating radio signal strengths on terrestrial paths at VHF and UHF, given a transmitter location, power, and a receiver location(s). Since transmission paths are often obstructed by terrain, CRC-PREDICT operate concurrently with a machine-readable topographic database consisting of elevation and surface codes; recorded at 25 m intervals.

When a path profile is present, the main calculation is that of diffraction attenuation due to terrain obstacles. These obstacles are primarily hills, or the curvature of the earth, but can also include trees and/or buildings. The presence and particular location of trees and buildings are considered in the calculation. If the user is aware of a particular obstacle consisting of trees or buildings that are not present in the terrain data, an additional loss estimate can be included. The diffraction calculation is done by starting at the transmitting antenna and finding the radio field at progressively greater distances. At each step, the field at a point is found by a numerical integration over the field values found in the previous step. For long paths, troposphere scatter becomes important. CRC-Predict combine the tropospheric scatter signal with the diffraction signal.

The field strength is calculated first at the height of the nearest building or trees and special formulas have been added to the CRC program to calculate the height loss from calculation height to 1.5 meter height. The height loss is not constant but it depends on the height of the near by buildings/trees as well as the distance to the transmitter.




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44..22 DDVVBB--HH CCOOVVEERRAAGGEE PPRREEDDIICCTTIIOONN

The DVB-H coverage prediction is normally done to certain geographical area. The user interfaces are different but it is most common to specify the calculation area on map. After the area has been determined the “pixel size” must be defined. The calculations are made to a grid of points and the “pixel size” is the distance between neighbouring calculation points. The calculation point is in the middle of the grid.

CRC-coverage prediction

The CRC coverage prediction and interface programs for DVB-H SFN-calculations are developed in Digita. First the calculation points are produced with MapBasic interface program where the calculation area is specified on map and the distance between points (“pixel size”) is given.

The propagation calculations are made from all stations in SFN network to every calculation point. The time delays between the first coming signal and other signals are calculated. The power sum of all signals which are inside the guard interval is calculated and that value is the median equivalent field strength. The signals (if any) which are outside guard interval are taken as interfering signals and are used in SFN self-interference calculations.

When all propagation calculations are done a MapInfo MIF file is written and the calculation result is imported into map. Attached is calculated coverage area of DVB-H network in Helsinki area. In the yellow area the calculated is the median equivalent field strength is above 80 dBµV/m and in red area between 75 an 80 dBµV/m at the height of 1.5 meters. The SFN-network consists of 13 main stations, typically ERP 4 kW and 4 gap-fillers, ERP 100 W.




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Figure 1, Helsinki area DVB-H coverage prediction




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55 FFIIEELLDD MMEEAASSUURREEMMEENNTTSS

Field measurements are necessary in order to verify the accuracy of the coverage prediction. When the measurements and predictions are compared only field strength measurements with location information are needed. DVB-H receiver which gives BER, packet error, frame error, RSSI etc. information can also be stored.

55..11 MMEEAASSUURRIINNGG SSYYSSTTEEMM

The field measurements are done with specially equipped vehicle. The measuring system of Digita measuring vehicle is shown in figure 2. The field strength values were measured with R&S ESVP Field Strength meter connected to calibrated antenna. Using external trigger the field strength samples were taken 600 times per second. The field strength data with location coordinates were stored on every second. The measuring PC software has been done in Digita.

Figure 2, Vehicle measuring system

55..22 AANNAALLYYZZIINNGG MMEETTHHOODD




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The analysing software were used, one for comparisons between measured and predicted field strength and the other for location variation analyses.

Analyses for comparisons

The comparison program divided the whole measuring route into 25 meter sections. The coordinates, Emin, Emed and Emax were stored for each 25 meter section. If the vehicle was driven in two seconds time 22 meters and in three seconds time 34 meters then 1350 values (1200, two first seconds plus 150 (600*3/12), third second) were taken to get exactly those measurements which were in this 25 meter section. The output files of this program were used as an input for propagation prediction software.

Analyses for location variation

The program used in location variation analyses was modified from the comparison program. The distance where the data was taken was put as input parameter. Then all measured field strength values within the specified distance were selected. If the specified distance was less than the driven distance during one second then only part of the 600 measured field strength values were taken. For instance if the specified distance was 1 meter and during the second 10 meters were driven, only 60 first measurements were taken for analyses.

For each specified distance the mean value and standard deviation of the field strength were calculated and stored with coordinates and Emin and Emax values into file. Also the distributions of the field strength samples were stored.

For the whole route the minimum, mean and maximum standard deviations of the specified section standard deviations were calculated. Also the difference between 95 % and 99 % and mean field strength values were calculated.




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Sect. (m)

Std min

Std max

Std mean 95 % 99 %

No of sect.

1 0 4.6 0.9 1.6 2.7 53425

2 0 4.4 1.1 2 3.2 26102

5 0 4.5 1.3 2.3 3.6 9854

10 0 4.5 1.5 2.5 3.9 4567

15 0 4.3 1.6 2.7 4.1 2885

20 0 5 1.6 2.8 4.3 1747

25 0 4.9 1.6 2.8 4.3 1694

30 0 5.4 1.7 2.9 4.5 1445

40 0 4.5 1.7 3 4.7 893

50 0 5 1.8 3.1 4.9 864

75 0 5.4 1.9 3.4 5.5 580

100 0 5.3 2 3.4 5.6 488

150 0 6.2 2.2 3.9 6.9 326

200 0 6.8 2.3 4.1 7.4 255

300 0 6.7 2.5 4.7 8.2 172

400 0.2 6.9 2.8 5.3 8.4 130

500 0.2 7.1 3 5.5 9.3 103

Table 2. Output of location variation analysing program




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66 CCOOMMPPAARRIISSOONNSS BBEETTWWEEEENN MMEEAASSUURREEMMEENNTTSS AANNDD

PPRREEDDIICCTTIIOONNSS

DVB-H field measurements were done in the beginning of 2007 in three places in Finland, in Helsinki Turku and Oulu area. The CRC-propagation prediction program was modified so that the coordination points for the calculations were taken from the measurements analyses program output file. The propagation calculations were done to all 25 meter sections. Table 3. shows the beginning of the CRC comparison program output file.

Lat Lon Meas-Calc Calc Meas PKatt RXheight

60.2726707 25.0958691 -0.7 102.3 101.6 12.0 8.0

60.2728691 25.0960503 -5.6 103.0 97.4 12.0 8.0

60.2734299 25.0966301 -8.7 105.7 97.1 12.0 8.0

…………………………

Table 3. Output of CRC-comparison program

The results of the comparisons were imported into both EXCEL and MapInfo for further analyses. There is no direct way to calibrate the CRC program and therefore an iterative approach was necessary. The program, mainly the height loss formula, was modified and new comparison calculation was performed. The main target was to try to minimise the standard deviation of the difference between measured and calculated field strength. After several modification and calculation rounds no further improvement was seen. The following results are after the modifications were done.

Comparisons in Helsinki area

The Helsinki area measurements are shown in figure 3.




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Figure 3, Helsinki area measurements

The measured field strength values are shown in different colours. The table 4. shows the comparison results in Helsinki area.

COMPARISONS BETWEEN MEASURED AND CALCULATED

FIELD STREGTHS IN HELSINKI AREA

Case Count Mean Stdev

All 42482 1.2 6.2

F-S > 90 dBµV/m 12621 6.3 6.3

90 < F-S < 80 dBµV/m 16393 -0.1 3.8

80 < F-S < 70 dBµV/m 10284 -2.5 5.1

F-S < 70 dBµV/m 3184 -0.2 7.3

Table 4. Comparison results in Helsinki area

The mean difference (measurement – prediction) was 1.2 dB and the standard deviation 6.2 dB. The measurements were divided according to the measured F-S into four categories to find out if there are




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differences. Near the stations (F-S > 90 dBµV/m) there were the biggest differences but this is in practice not so important, there are no problems with the coverage. The best results were got when the measured F-S was between 80 and 90 dBµV/m, the biggest number of comparisons and the StDev only 3.8 dB. When F-S is below 70 dBµV/m, too low for good service, standard deviation is the highest.

Comparisons in Turku area

In Turku there are at this moment only two DVB-H stations. Therefore the coverage area is much smaller compared to Helsinki area and the field strength is less then 70 dBµV/m in most of the measure routes. The original CRC-prediction model gave too high field strengths for distances outside the coverage area. It was calibrated to give closer results compared to measurements. The Turku area measurements are shown in figure 4 and table 5 shows the comparison results in Turku area.

COMPARISONS BETWEEN MEASURED AND CALCULATED FIELD STREGTHS IN TURKU AREA


All 19169 -1.6 6.6

F-S > 90 dBµV/m 1535 1.0 7.1

90 < F-S < 80 dBµV/m 2365 -0.6 4.7

80 < F-S < 70 dBµV/m 4996 -1.4 5.4

F-S < 70 dBµV/m 10272 -2.2 7.3

Table 5. Comparison results in Turku area

The mean value (measured – predicted) is 2.7 dB lower than in Helsinki and standard deviation 0.4 dB higher. Again the lowest standard deviation is on field strengths 80 – 90 dBµV/m and the highest above 90 and below 70 dBµV/m.




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Figure 4, Turku area measurements

Comparisons in Tampere area

In Tampere area there are at five vertically polarized DVB-H stations. The ERP’s are 9 – 13 kW and antenna heights 84 – 91 meters. Tampere area field strength measurements are shown in figure 5

and table 6 shows the comparison results in Tampere area.




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Figure 5, Tampere area measurements

COMPARISONS BETWEEN MEASURED AND CALCULATED FIELD STREGTHS IN TAMPERE AREA


All 34530 0.6 6.5

F-S > 90 dBµV/m 6518 7.5 6.5

90 < F-S < 80 dBµV/m 14541 1.2 4.9

80 < F-S < 70 dBµV/m 10649 -2.7 4.4

F-S < 70 dBµV/m 2822 -5.7 6.3

Table 6. Comparison results in Tampere area

The mean value (measured – predicted) is 0.6 dB and standard deviation 6.5 dB. The lowest standard deviation is on field strengths 70 – 80 dBµV/m and the highest above 90 and below 70 dBµV/m. These




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values very close to Helsinki and Turku SFN network comparisons.

Comparisons in Oulu area

During the first Oulu measurements there was one high power station using the same antenna as DVB-T transmissions. The antenna height is 300 m and ERP 50 kW. The Oulu area measurements are shown in figure 6 and table 7 shows the comparison results in Oulu area.

Figure 6, Oulu area measurements




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COMPARISONS BETWEEN MEASURED AND CALCULATED FIELD STREGTHS IN OULU AREA


All 29608 2.9 5.6

F-S > 90 dBµV/m 4652 7.6 5.8

90 < F-S < 80 dBµV/m 13973 3.0 4.7

80 < F-S < 70 dBµV/m 9416 0.6 5.2

F-S < 70 dBµV/m 1576 2.0 6.2

Table 7. Comparison results in Oulu area

The calculated field strength values are about 3 dB lower than measured. The Oulu area is very flat and that may be the reason for the average difference.

66..11 CCOONNCCLLUUSSIIOONNSS

The results in this study are preliminary and the analyses will continue next year. Especially further studies of SFN gain are needed.

Comparisons between measurements and predictions show that the overall standard deviation is in the order of 6dB. If the field strength is higher than 90 dBμV/m there is always good service and if the field strength is below 70 dBμV/m there is no coverage and prediction errors are not so important. For planning the important field strength levels are 70 – 90 dBμV/m. On that area the standard deviation between measurements and predictions are in the order of 4 - 5 dB.




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77 LLOOCCAATTIIOONN VVAARRIIAATTIIOONNSS

A great number of analyses were done in Digita in order to get better understanding of the location variation of the field strength in SFN network.

Helsinki area analyses

Altogether 33 measuring routes were analysed with the analysing program explained in section 5. In figures 7 – 10 are example of analyses in central Helsinki urban area, standard deviations are plotted on map for 10, 25, 50 and 100 meter sections. Figures 11 – 14 show similar analyses in Espoo sub-urban area and figures 15 -1 8 show 10, 50, 100 and 200 meter sections in rural area.

Figure 7, Urban analyses, 10 meter sections




Figure 11, Sub-urban analyses, 10 meter sections




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©B21C Project WP3 - Deliverable XX Page : 28 (54)


Figure 15, Rural analyses, 10 meter sections





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The above figures show that the standard deviations of the location variations increase when the analysed sections become longer. In urban area the “pixel size” should be smaller than in rural area for accurate calculations.

The location variations were analysed with EXCEL. Figure 19 and 20 show how the standard deviations of the location variations increase in Helsinki area measurements when section length increases.

Means of the standard deviations of the field strengths

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1 2 5

10

15

20

25

30

40

50

75

10

0

15

0

20

0

30

0

40

0

50

0

Analysed distance (m)

dB

Keha3_1

Kehä3_2

Espoo_centrum

Tapiola

Itäkeskus

Jäähalli

Jän-Sello

Jäm-Soukka

Jumbo

Leppäv_1

Leppäv_2

Messukeskus

Mtjpaa

Figure 19, Helsinki location variation analyses



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©B21C Project WP3 – Deliverable XX Page : 30 (54)

Means of the standard deviations of the field strengths

0

0.5

1

1.5

2

2.5

3

3.5

4

1 2 5 10 15 20 25 30 40 50 75 100

150

200

300

400

500


dB

Myyri

Otaniemi

Sello

Espoo

Jpaa

K-nummi

L-as

L-as_ymp

Tuusula

Itä-Hki

Sipoo

Korso

Savio

Nahkela

Figure 20, Helsinki location variation analyses

The mean values for all Helsinki area 31 measuring routes were also calculated. The mean standard deviations of location variations as well as 95% and 99% values are shown in figure 21. The 95% curve shows the value when 95% of standard deviations are lower or equal. The 99% curve shows the values when only 1% of the standard deviations are higher.



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Means of the location variariations of the field strengths

0

1

2

3

4

5

6

7

8

9

10

1 2 5

10

15

20

25

30

40

50

75

10

0

15

0

20

0

30

0

40

0

50

0


dB

Helsinki_Stdev

Helsinki_95%

Helsinki_99%

Figure 21, Mean location variations of all Helsinki area measurements

Turku area analyses

Similar analyses were done in Turku area measurements. Figures 22 – 25 show an example of analyses in central Turku urban area; standard deviations are plotted on map for 10, 25, 50 and 100 meter sections.

Figure 22, Turku urban area,10 m

Figure 23, Turku urban area, 25 m



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Figure 26 shows how the standard deviation of the location variation increases as a function of distance in different parts of Turku area.

Means of the location variation of the field strengths

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1 2 5 10 15 20 25 30 40 50 75 100

150

200

300

400

500


dB

IsoH

LahiKeskus

LahiPaask

PeitoHirve

Lieto

Masku

Paimia

Parainen

Piikkiö

Ruissalo

Rusko

Figure 26, Turku location variation analyses

Figure 27 shows how the mean standard deviation of the location variation of all Turku measurements increases when the analysed distance increases.



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Means of the location variariations of the field strengths

0

1

2

3

4

5

6

7

8

9

10

1 2 5 10 15 20 25 30 40 50 75 100

150

200

300

400

500


dB

Turku_Stdev

Turku_95%

Turku_99%

Figure 27, Mean location variations of all Turku area measurements

The Turku area location variations are quite similar to Helsinki area results.

Tampere area analyses

Similar analyses were done in Tampere area measurements. Figures 28 – 32 show the analyses in central Tampere area, location variation standard deviations are plotted on map for 25, 50, 100, 200 and 500 meter sections.

Figure 28, Tampere area, 25 m




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Figure 33 show the standard deviation of location variation versus distance (“pixel size”)



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Figure 33, Mean location variations of all Tampere area measurements

Oulu area analyses

Two different measurements were done in Oulu. In the first measurement there was on horizontally polarised station and in the second two additional vertically polarised stations. Figures 34 – 38 show the standard deviations of the location variation in the first measurement (1 station) and figure 39 – 43 the second measurement (3 stations) for 25, 50, 100, 200 and 500 meter sections.

Figure 34, Oulu 1 station, 25 m


Means of the location variation of the field strengths

0

2

4

6

8

10

12

10 15 20 25 30 40 50 75 100 150 200 300 400 500


dB

Tampere_Stdev

Meas_95%

Meas_99%



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Figure 39, Oulu 3 stations, 25 m



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Figure 4 shows how the mean standard deviation of the location variation of both Oulu measurements. The standard deviation is 0.5 – 1 dB higher in the one station case and in the measured 99% case the difference is 2 – 3 dB.





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Figure 44, Mean location variations of both Oulu area measurements


Figure 48 shows the summary of the standard deviations of the field strengths of all DVB-H measurements. The four SFN networks are rather similar in “pixel size” 10 – 100 m. In distances 100 – 500 there are some differences, at 500 meter “pixel size” from 2.6 to 3.6. The Oulu MFN (1 station) measurements give higher standard deviations in al “pixel sizes”.

The location variation of dense SFN-network is much smaller than normally used in link budgets (5.5 dB). It depends on the “pixel size”, the summary results are in table 8. If the 95 and 99 % values are calculated from standard deviation assuming that the field strength values are normally distributed they are somewhat smaller than average measured values. This indicates that the field strength distribution is not exactly normally distributed.



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Figure 45, Mean standard deviations of all DVB-H measurements



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Measured Calculated

Pixel size StDev 95 % 99 % 95 % 99 %

10x10 1.6 2.5 4.0 2.6 3.7

20x20 1.8 2.9 4.7 3.0 4.2

50x50 2.0 3.3 5.4 3.3 4.7

100x100 2.2 4.0 6.7 3.6 5.1

150x150 2.4 4.3 7.3 3.9 5.6

200x200 2.6 4.7 7.9 4.3 6.1

300x300 2.8 5.2 8.6 4.6 6.5

400x400 3.0 5.5 8.9 4.9 7.0

500x500 3.2 6.0 9.2 5.2 7.5

Table 8. Location variation in SFN network

The location correction should be calculated with formulas

Cl = µ σt

σt =22

pv

where:

Cl : location correction factor (dB)

σt : Total standard deviation (dB)

σv: standard deviation of location variation (dB)

σp : standard deviation prediciton error (dB)

µ : distribution factor being 0.52 for 70%, 1.28 for 90%, 1.64 for 95% and 2.33 for 99%.

An example, pixel size 100 x 100, 95 % of time:

σv = 2.2 dB

σp = 4.5 dB

µ = 1.64

Cl = 1.64 * 5.01 = 8.2 dB



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88 DDVVBB--TT//HH CCOOMMPPAATTIIBBIILLIITTYY

DVB-H requires much higher field strength than DVB-T and therefore the network structure is different. DVB-H SFN network normally consists of several small/median power transmitters and gap-fillers. DVB-H can cause interference to DVB-T reception.

There is a need to:

Verify or update DVB-T protection ratios in presence of DVB-H interference

Measure DVB-H interference level to block DVB-T receiver

Specify critical distance from DVB-T reception site to DVB-H transmitter

The following items have been studied:

DVB-T Receiver performances under normal operation

DVB-T receiver performance under overload conditions

Impact on DVB-H network design

88..11 MMEEAASSUURREEMMEENNTTSS

The measurement set-up is shown in figure 46.

The used wanted DVB-T signal is was 8k, 64 QAM, CR 2/3, GI 1/32, frequency 650 MHz. The Tx power was varied, receiver sensitivity +3 dB / 10 dB / 20 dB / 30 dB. The target was to evaluate protection ratio, impact of receiver overload on selectivity and worst-case receiver overload.

The Interfering DVB-H signal was 8k, 16 QAM, CR ½ and GI 1/8, max power -2 dBm

Following low cost (less than 90 €) receivers were tested:

– Technisat digipal 2

– Philips DTR-210

– Metronic Zapbox Slim

– Newsat RNT 100

– Elap Thema V



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Figure 46, Measurement set-up

Protection ratio results

Sensitivity

– -83 dBm (4 receivers) to -84 dBm (1 receiver)

Protection ratio

– Useful DVB-T signal level at receiver sensitivity +3dB

– Criterion: No visible impairment during 60 s

– In agreement with IEC 62216-1 (-26 dB in adjacent channel, -40 dB in others except image channel)

– Tested receivers have much better protection ratio than IEC for non adjacent channels

This is independent of the DVB-H interfering signal level (below overload threshold)



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Figure 47, Protection ration results

Figure 48, Worst case protection ratio

Measured DVB-T protection ratios compared

with those defined in EMC standard IEC 62216-1

-80

-70

-60

-50

-40

-30

-20

-10

0

-80 -72 -64 -56 -48 -40 -32 -24 -16 -8 0 8 16 24 32 40 48 56 64 72 80

Frequency offset in MHz (fi-fu)

C/I (

dB

)

Measured w orst-case C/I (DVB-T signal leve=sensitivity+3 dB, f=650 MHz)

C/I defined in IEC 62216-1

DVB-T protection ratios defined by measurement

(DVB-T signal leve=sensitivity+3 dB; fu=650 MHz)

-90

-80

-70

-60

-50

-40

-30

-20

-80 -72 -64 -56 -48 -40 -32 -24 -16 -8 0 8 16 24 32 40 48 56 64 72 80


C/I (

dB

)

Rx_1 Rx_2 Rx_3 Rx_4 Rx_5 Worst-case C/I curve



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DVB-T receiver overload

DVB-T Receiver Overload conditions

– Useful DVB-T signal levels at receiver sensitivity +10 / 20 / 30 dB – Interfering DVB-H signal level adjusted to overload receiver –

Receiver Overload results – Overload power thresholds are very high (–18 dBm to –2 dBm) – In some cases the interfering DVB-H signal level was not sufficient

(–2 dBm) – No impact of DVB-T signal level

Figure 49, Interference levels that blocks the receiver

Impact of strong DVB-H signal on Protection ratio:

– Protection ratio is dramatically increased for most receivers (3 out of 5). The receiver loses its ability to discriminate interfering signals

– Protection ratio remains quite unchanged for the best receivers (#4 and #5)

DVB-H interfering levels higher than overload level

DVB-T receiver front-end overlod thresholds defined by measurement

(DVB-T signal leves=sensitivity+10, 20 and 30 dB dB; fu=650 MHz)

-40

-30

-20

-10

0

10

-80 -72 -64 -56 -48 -40 -32 -24 -16 -8 0 8 16 24 32 40 48 56 64 72 80


I p

ow

er

(dB

m)

Rx_1 Rx_2 Rx_3 Rx_4 Rx_5 Worst-case thresholds



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Figure 50, Protection ratio, typical receiver

Figure 51, Protection ratio, best receiver

Rx_5 (fu=650 MHz)

-90

-80

-70

-60

-50

-40

-30

-20

-80 -72 -64 -56 -48 -40 -32 -24 -16 -8 0 8 16 24 32 40 48 56 64 72 80


C/ I (d

B)

Rx_sens+3 dB Rx_sens+10 dB Rx_sens+20 dB Rx_sens+30 dB

Rx_1 (fu=650 MHz)

-80

-70

-60

-50

-40

-30

-20

-80 -72 -64 -56 -48 -40 -32 -24 -16 -8 0 8 16 24 32 40 48 56 64 72 80


C/I (

dB

)

Rx_sens+3 dB Rx_sens+10 dB Rx_sens+20 dB Rx_sens+30 dB



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88..22 IIMMPPAACCTT OONN NNEETTWWOORRKK PPLLAANNNNIINNGG Hypotheses

– Free space calculations, same polarisation – DVB-H

– Tx power 10 W to 4 kW EIRP – Height 20 to 100 m

– DVB-T receiver – antenna height: 10 m – antenna gain: 12 dB (- 3 dB cable loss) –

Minimum distances (for DVB-H at 4 kW, 100 m high) – Low performance receiver: overloaded at 370 m

High performance receiver: overloaded at 20 m

Figure 52, High quality receiver

Receiver front-end overload distance from the DVB-H radio site

(DVB-H transmitter height = 100 m, DVB-T receiver height = 10 m)

-50

-40

-30

-20

-10

0

10

0 50 100 150 200 250 300 350 400 450 500

Distance (m)

I lev

el (d

Bm

)

4 kW (e.r.p) 2 kW (e.r.p)

1 kW (e.r.p) 500 W (e.r.p)

200 W (e.r.p) Overload th =-4 dBm (at N+3)



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Figure 53, Low quality receiver

Possible solutions to DVB-H interference on DVB-T receivers – On Transmitter side

– Increase the transmit power: primarily on small power sites – Filtering of DVB-H Tx signal – Use alternate frequency

– On receiver side: ad hoc solutions

– Attenuate input signal – Improve receivers – Move DVB-T antenna

Receiver front-end overload distance from the DVB-H radio site

(DVB-H transmitter height = 100 m, DVB-T receiver hieght = 10 m)

-50

-40

-30

-20

-10

0

10

0 50 100 150 200 250 300 350 400 450 500

Distance (m)

I lev

el (d

Bm

)

4 kW (e.r.p) 2 kW (e.r.p)1 kW (e.r.p) 500 W (e.r.p)200 W (e.r.p) Overload th =-18 dBm (at N±3)Overload th =-14 dBm (at N+4) Overload th =-8 dBm (at N+8)Overload th =-6 dBm (at N-9)



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Protection ratios

– In the case of normal DVB-T receiver operation, receivers are (more than) compliant to IEC 62216-1. The standard could be more demanding

– In the case of DVB-T receiver overloading, protection ratio defined in IEC 62216-1 could be applied as a function of interfering signal level and frequency.

– Do not use DVB-T adjacent channels to plan DVB-H

Network impact

– Overall the DVB-T receivers have a sufficient performance to reject DVB-H.

Only in some local cases receiver distance to DVB-H Transmitter might be too small. This can be avoided by careful network design and ad-hoc solutions



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99 CCOONNSSIIDDEERRAATTIIOONN OOFF SSPPEECCTTRRUUMM OOTTHHEERR TTHHAANN

UUHHFF FFOORR DDVVBB--HH

99..11 IINNTTRROODDUUCCTTIIOONN The motivation for this study is that UHF is overall heavily used introducing mobile television in UHF may require spectrum optimisation or reallocation. Another aspect of the issue is that a pan-European frequency band for mobile television is desirable in order to enable cross-border operation of terminals. In this context, this section outlines the current status in Europe concerning the spectrum potentially used by mobile television, and investigates the technical implications of using spectrum other than the UHF band for mobile television. In the framework of B21C, this study concerns particularly DVB-H, which is available on the market now.

In the following paragraphs, section 9.2 will outline the spectrum regulatory status and list the possibilities which are available to implement DVB-H. Section 9.3 will focus on the technical impacts of an alternative frequency, considering mainly VHF and L bands. Finally, the current national status in several countries is described.

99..22 SSPPEECCTTRRUUMM SSTTAATTUUSS FFOORR DDVVBB--HH SSEERRVVIICCEESS Frequency spectrum is regulated at the international level by the ITU in order to enable interoperability of wireless services. At the European level, the European Conference of Postal and Telecommunications administration (CEPT) is the body responsible for this regulation. Concerning terrestrial broadcast services, several bands may be used as follows:

- VHF (170 MHz – 240 MHz)

- UHF (470 MHz – 862 MHz);

- L band (1452 MHz – 1492 MHz)

The DVB-H standard has been designed for these three bands. A brief status and characteristics of these bands is as follows.

VHF band III

In Europe the VHF band is currently allocated and used for terrestrial analogue and digital Television services and terrestrial digital radio services (DAB). The use of these frequencies has been agreed during the ITU Regional Radiocommunication Conference in May-June 2006 (RRC-06). However, it seems that most digital television services are implemented in UHF, mostly leaving VHF for Digital radio.

VHF has very good propagation properties which would enable to use few transmitters to provide a good coverage. However this advantage is counterbalanced by several terminal constraints such as suboptimal reception because the antennas are very small compared to the signal wavelength. This is especially true in the case of mobile handheld TV.

UHF band IV/V

The UHF band is allocated and used for analogue and digital terrestrial television. Despite the heavy UHF usage, it seems to be possible to find UHF frequencies to deploy mobile TV in some European countries, at least in cities, based on the ITU Regional Radiocommunication Conference in May-June 2006 (RRC-06).

UHF has interesting propagation properties, though less good than VHF. Also, in case of a DVB-H/GSM



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converging terminal, DVB-H can only be used in the lower range of UHF (470 MHz – 698 MHz) due to GSM uplink interference. However UHF allows good reception on handheld devices, and has been used for most DVB-H trials throughout Europe.

L band

L-band has been allocated to terrestrial and satellite Digital Audio Broadcasting (DAB) services in two steps during 1995 Wiesbaden and 2002 Maastricht CEPT conferences. The lower part 1452-1479 MHz can be used for terrestrial DAB. However DAB did not take up and most of the 25 MHz bandwidth split into 1.7 MHz channels is often available. DVB-H could accommodate this band under the assumption that several consecutive DAB channels can be aggregated to match 5, 6, 7 or 8 MHz bandwidth required by DVB-H, which needs regulation decisions.

L-Band has more or less line-of-sight propagation properties, which means that more transmit stations than VHF or UHF will be needed to cover a similar area. On the other hand good antenna integration in a handheld terminal is possible.

VHF III UHF IV/V L-band

Propagation ++ + –

Antenna size (handheld terminal) – – + ++

Availability / regulation issues – + –

Table 1: Comparison of Frequency bands merits for handheld mobile TV

99..33 FFRREEQQUUEENNCCYY BBAANNDD IIMMPPAACCTT OONN SSYYSSTTEEMM AANNDD

NNEETTWWOORRKK AARRCCHHIITTEECCTTUURREE

99..33..11 IIMMPPAACCTT OOFF VVHHFF Due to the physical constraint on antenna size which is difficult to accommodate to a handheld terminal, and because this band is often already used by fixed digital TV, it is not considered relevant to consider VHF as a realistic alternative to UHF.

99..33..22 IIMMPPAACCTT OOFF LL--BBAANNDD

99..33..22..11 LLIINNKK BBUUDDGGEETT

The goal of this section is to establish a comparative link budget between UHF and L-band for DVB-H transmission, considering the same coverage targets and usage options as follows:

- Outdoor, indoor pedestrian and in-car reception on a handheld terminal with integrated antenna, roof-top reception on a terminal integrated to a car.

- Good coverage, i.e. 95% of receiving locations for pedestrian usage and 99% of receiving locations for mobile usage.

- Use of 7 MHz DVB-H channel in L-band, resulting from the aggregation of four T-DAB channels of 1.712 MHz. This choice is motivated by the need to optimise spectrum usage, by choosing the highest ratio of effective DVB-H bandwidth and aggregated 1.712 MHz channels. Effective DVB-H bandwidth for 5, 6, 7, 8 MHz systems are 4.754 , 5.705, 6.656 or 7.607 MHz respectively.



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The link budget is established according to the methodology and figures used by the BMCOforum (Broadcast Mobile Convergence Forum) [3]. Applying this methodology, it appears that the main items that differ are, in the case of deep indoor usage:

- L-band antenna gain which is up to 5 dB higher than in UHF

- L-band building penetration losses are 2 dB higher

- L-band higher frequency affects effective antenna aperture by –7 dB compared to UHF (698 MHz)

Also, reducing system bandwidth from 8 to 7 MHz is beneficial to L-band but marginal (0.5 dB).

Table 2 shows the detailed comparative UHF and L-band link budgets, for good deep indoor coverage. The better antenna gain does not fully compensate for higher L-band attenuation.

Frequency f (MHz) 698

Bandwidth B (MHz) 8

Modulation QPSK 1/2 MPE 3/4

Reception Deep Indoor

Quality Good

Frequency f (MHz) 1452

Bandwidth B (MHz) 7

Modulation QPSK 1/2 MPE 3/4

Reception Deep Indoor

Quality Good

Noise factor F (dB) 6

Boltzmann constant K 1,38E-23

Temperature T (K) 290

Bandwidth B (MHz) 7,61

C/N (dB) 7,5

Reception antenna gain Gr (dBd) -9,2

Penetration Losses p (dB) 17

Combined Standard deviation (dB) 8,1

Correction coefficient 1,64

Polarisation mismatch (dB) 0

Manmade noise (dB) 0

Implementation margin (dB) 3

Minimum median equivalent field

strength at 1.5 m (50% time)83 dBuV/m

Minimum received power at 1.5 m

(50% time)-58 dBm

Noise factor F (dB) 6

Boltzmann constant K 1,38E-23

Temperature T (K) 290

Bandwidth B (MHz) 6,66

C/N (dB) 7,5

Reception antenna gain Gr (dBd) -4,2

Penetration Losses p (dB) 19

Combined Standard deviation (dB) 8,1

Correction coefficient 1,64

Polarisation mismatch (dB) 0

Manmade noise (dB) 0

Implementation margin (dB) 3

Minimum median equivalent field

strength at 1.5 m (50% time)86 dBuV/m

Minimum received power at 1.5 m

(50% time)-56 dBm

Table 2: Comparative link budgets and required field strengths for UHF and

L-band, for Good Deep indoor coverage

Applying the same process to all use cases classes and various typical configurations results in Table 3 and Table 4.

DVB-H

698 MHz

QPSK ½

MPE FEC 3/4

QPSK 2/3

MPE FEC 3/4

16QAM ½

MPE FEC 3/4

16QAM 2/3

MPE FEC 3/4

C – Mobile roof-top 62 dB V/m 65 dB V/m 68 dB V/m 71 dB V/m

A – Outdoor 62 dB V/m 65 dB V/m 68 dB V/m 71 dB V/m

D – Mobile in-car 74 dB V/m 77 dB V/m 80 dB V/m 83 dB V/m

B1 – Light indoor 76 dB V/m 79 dB V/m 82 dB V/m 85 dB V/m

B2 – Deep indoor 83 dB V/m 86 dB V/m 89 dB V/m 92 dB V/m

Table 3: DVB-H link budgets for UHF



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DVB-H

1452 MHz

QPSK ½

MPE FEC 3/4

QPSK 2/3

MPE FEC 3/4

16QAM ½

MPE FEC 3/4

16QAM 2/3

MPE FEC 3/4

C – Mobile roof-top 67 dB V/m 70 dB V/m 73 dB V/m 76 dB V/m

A – Outdoor 62 dB V/m 65 dB V/m 68 dB V/m 71 dB V/m

D – Mobile in-car 74 dB V/m 77 dB V/m 80 dB V/m 83 dB V/m

B1 – Light indoor 79 dB V/m 82 dB V/m 85 dB V/m 88 dB V/m

B2 – Deep indoor 86 dB V/m 89 dB V/m 92 dB V/m 95 dB V/m

Table 4: DVB-H link budgets for L-band

It follows that in some cases the required field strength in L-band is similar to UHF (pedestrian outdoor and Mobile in-car), but significantly higher for other cases, such as the most demanding one (+3 dB for deep indoor).

99..33..22..22 MMOOBBIILLIITTYY IISSSSUUEESS

Using a higher frequency also has an impact on Doppler frequency shift that is experienced by the terminal. Since the Doppler shift is proportional to the carrier frequency, the Doppler shift is multiplied by 2 or 3, since the L-band / UHF frequency ratio is between 2 and 3. It results that given a maximum Doppler frequency supported by the receiver, the maximum speed is reduced by the same amount.

In order to support mobility use cases (Mobile roof-top and mobile in-car), a reasonable maximum speed is 130 km/h. Transposing the DVB-H implementation guidelines [4] to L–band will leave no choice but using 2k and 4k modes, which reduce the duration of the guard interval (Table 5).

Table 5: Doppler and Speed figures in UHF (500 MHz)

This is a very strong constraint, considering that DVB-H networks would use Single Frequency Network mode, because reducing the distance between transmitters leads to a more dense and costly network.

99..33..22..33 NNEETTWWOORRKK DDIIMMEENNSSIIOONNIINNGG

In order to compare the amount of transmitters needed for L-band and UHF, the difference in signal attenuation has to be evaluated. To this end, the COST 207 attenuation model has been used at 1466 MHz, considering a theoretical regular network composed of low power transmitters compared to traditional broadcast high power sites. With the same transmit power in UHF and L-band, and considering the same regular network structure in UHF and L-band, this theoretical model shows that about three times more sites are needed in L-band compared to UHF, which inevitably strongly affects



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network building and operational costs.

It appears that L-band has an interest in terms of network costs if it is restricted to the least demanding usages (e.g. pedestrian Outdoor, mobile roof-top). UHF is a good trade-off between network costs, mobility, building penetration losses and antenna integration in the handheld terminal.

99..44 SSTTAATTUUSS OONN FFRREEQQUUEENNCCYY BBAANNDDSS UUSSEEDD FFOORR DDVVBB--HH

IINN SSEEVVEERRAALL EEUURROOPPEEAANN CCOOUUNNTTRRIIEESS

99..44..11 FFIINNLLAANNDD The license for one Geneva 06 agreement UHF-layer covering the whole country has been granted by Finnish Communications Regulatory Authority to Digita. The DVB-H free to air service started in 2006 with five TV and three radio programs. The existing network covers 40% of population in six major cities. The negotiations with content providers are going on and the full DVB-H service is expected to be launched by the end of 2008. The DVB-H network will be extended as required by the content providers. There are currently no plans to use channels other than UHF channels 21-55, as VHF band 3 and L-band are allocated to other services in Finland and/or in the neighbouring countries.

99..44..22 FFRRAANNCCEE In France DVB-H has been officially selected as the technology for Mobile TV broadcasting in the UHF bands IV/V, and DVB-SH for the S-band. The DVB-H service is planned to be launched early 2009, in the UHF band. The media regulator has already selected all DVB-H channels (13 private plus 3 pre-empted for public services). The channels editors are now due to create a multiplex operator (together with the Mobile Network Operators).

The target coverage with DVB-H demanded by the regulation authorities is limited in the period until the switch off: 30% of the population outdoor after 3 years. The plan is to use the frequency layers from Geneva 06 agreement, which will be made available after the switch off in 2011 to extend the coverage in UHF band IV/V, which is the selected spectrum for DVB-H.

99..44..33 GGEERRMMAANNYY In Germany Mobile TV has been on air with T-DMB in the L-band until last may. A new service based on DVB-H is under preparation. The licenses needed to launch a DVB-H service have been granted by the Federal State Media Authorities to Media Broadcast regarding the network and spectrum, and to the Mobile 3.0 regarding the services. The current plan is to roll-out the network to Germany’s 16 largest cities by the end of 2008, in the UHF band IV/V.

99..44..44 IITTAALLYY In Italy two commercial DVB-H networks are operational since 2006, transmitting in the UHF bands IV/V. No special range of frequencies within the UHF band has been allocated to DVB-H services, but available UHF channels are used by the operators in the various coverage areas, in a multi-SFN network. The whole multiplex is dedicated to DVB-H. More than 1000 transmitters, from 5 W to



Deliverable D11-1


2.5 kW, are used to cover 85% of the population (outdoor coverage). The service content includes pay TV, free-to-air and pay-per-view programmes.

A DAB/T-DMB trial is currently going on, operating in the VHF band III and covering 75% of the population (outdoor coverage).

99..44..55 SSPPAAIINN The first step to have a well established regulatory framework for the frequency license is to have a general regulatory framework being adopted for mobile TV. Following the Public consultation the government issued a draft Law to set up the basic regulation of mobile TV, but the adoption of this Law by the Parliament has been postponed. The following schedule can be expected:

• License framework may be at the End 2008

• Tender opening is expected at 1st half 2009

• Licence granting may be at 2nd half 2009

The platform licence will be granted together with the frequency licence, for which no well established regulatory framework has been set so far.

Preferred Spectrum: UHF band

99..55 CCOONNCCLLUUSSIIOONNSS In this section the frequency bands which can be used for mobile TV in Europe (VHF: 170–240 MHz, UHF IV/V: 470–862 MHz and L–band: 1452–1492 MHz) have been studied. Theoretical network planning studies conclude that the use of L-band will have a strong impact on network architecture, as a denser network than in UHF band IV/V will be required to get the same coverage and use cases, including indoor reception. The number of sites may be up to three times higher, due to propagation characteristics in this band, and reduced guard intervals to enable mobility. There is no doubt that using L-band will strongly affect network building and operational costs. VHF is considered to be difficult to use in practice, particularly because the physical size of a reception antenna is not compatible with a handheld receiver.

Many European countries which have launched or are planning to launch mobile TV services have selected DVB-H and the UHF band IV/V restricted to channels 21-55 (474 – 750 MHz), using one of the layers from the Geneva 06 agreement. In most cases the current coverage is limited by the heavy use of this spectrum, but it is planned to be gradually extended as the switchoff of analogue services will progress until 2011.

b21c - d11-1 - dvb-h network planning

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