© Gianfranco Miele

UNIVERSITÀ DEGLI STUDI DI CASSINO

FACOLTA’ DI INGEGNERIA

Corso di sistemi radiomobili

Introduzione alle reti DVB-H

Gianfranco Miele

8 giugno 2007

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Contents

1 DVB-T system 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 General considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Channel coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.1 Transport multiplex adaptation and randomization for energy
dispersal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.2 Outer coding . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.3 Outer interleaver . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.4 Inner coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.5 Inner interleaver . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.6 Signal constellation and mapping . . . . . . . . . . . . . . . . 11
1.4 OFDM frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.5 Reference signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.5.1 Location of scattered pilot cells . . . . . . . . . . . . . . . . . 17
1.5.2 Location of continual pilot cells . . . . . . . . . . . . . . . . . 17
1.6 Transmission Parameter Signalling (TPS) . . . . . . . . . . . . . . . . 18
1.6.1 TPS transmission format . . . . . . . . . . . . . . . . . . . . . 19
1.6.2 TPS modulation . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.7 DVB-T system parameter summary and net data rate . . . . . . . . . 24
1.8 Spectrum characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.9 Time-domain signal characteristics . . . . . . . . . . . . . . . . . . . 26

A Additional features for DVB Handheld terminals (DVB-H) 29

A.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
A.2 Channel coding and modulation . . . . . . . . . . . . . . . . . . . . . 30
A.2.1 Inner interleaving . . . . . . . . . . . . . . . . . . . . . . . . . 30
A.3 OFDM frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . 33
A.4 Reference signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
A.4.1 Location of continual pilot carriers . . . . . . . . . . . . . . . 33
A.5 Transmission Parameter Signalling (TPS) . . . . . . . . . . . . . . . . 34
A.5.1 TPS transmission format . . . . . . . . . . . . . . . . . . . . . 34

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Chapter 1

DVB-T system

1.1 Introduction
The DVB Project is an alliance of about 250-300 public and private media interest
companies, originally of European origin but now worldwide.
Until late 1990, digital television broadcasting to the home was thought to be im-
practical and costly to implement. During 1991, broadcasters and consumer equip-
ment manufacturers discussed how to form a concerted pan-European platform to
develop digital terrestrial TV. Towards the end of that year, broadcasters, consumer
electronics manufacturers and regulatory bodies came together to discuss the forma-
tion of a group that would oversee the development of digital television in Europe.
This group was called European Launching Group (ELG), that provided to draft
a protocol named, Memorandum of Understanding (MoU), establishing the rules to
be adopted and respected by the members of the group. The Mou was signed by all
ELG participants in September 1993, and the Launching Group renamed itself as
the Digital Video Broadcasting Project (DVB).
DVB project has a bicameral structure:
• Commercial Module decides what features or cost levels are needed to make a
product a success.

• Technical Module is set the task of creating a technical specification which

meets the needs asked by the Commercial Module.
Finally, after the specification is prepared, the commercial module checks the tech-
nicians have done what was needed. Afterwards specifications are passed to the
European standards body for media systems, the European Broadcasting Union
(EBU)/Comité Européen de Normalisation ELECtrotechnique (CENELEC)/European
Telecommunications Standards Institute (ETSI), for approval. The specifications are
then formally standardised by either CENELEC or, in the majority of cases, ETSI.

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The first digital video broadcasting platform developed was the DVB-S system
for digital satellite broadcasting, in 1993. It is a relatively straightforward system
using QPSK modulation scheme and was introduced by the standard ETSI EN 300
421, approved in 1997. This standard describes different tools for channel coding
and error protection which were later used for other delivery media systems [1].
The DVB-C system for digital cable networks was developed in 1994. It is centred
on the use of 64-QAM modulation scheme, and for the European satellite and cable
environment can, if needed, convey a complete satellite channel multiplex on a cable
channel. The specification are described by the ETSI EN 300 429 standard [2].
Though digital television broadcasting via satellite and cable are accessible to
many households throughout the world, the DVB project decided to design an ad-
ditional coverage with digital terrestrial television for the following reasons [3]:
• Many countries in the world do not have satellite TV coverage, or only in-
adequately so, for the most varied reasons of a political, geographic or other
nature. In many cases, substitute coverage by cable is not possible, either,
because e.g. permafrost and also often can be financed because of sparse
population density. This leaves only the terrestrial coverage.
• The previous systems are not able to supply local supplementary municipal
services (regional/urban television).
• Portable and mobile reception is virtually only possible via the terrestrial path.
In 1995, the terrestrial standard for the trasmission of digital TV programs was
defined in (EN 300 744) [4]. This standard was more complex because it was intended
to cope with a different noise and bandwidth environment, and multi-path. The
key element is the use of the Orthogonal Frequency Division Multiplexing (OFDM).
There are two transmission modes: the 8K mode, that allows more multi-path
fading protection and 2K mode, that offers Doppler advantages where the receiver
is moving.
In this chapter is carried out an exhaustive description of the DVB-T standard
[4], focusing the attention to the transmitter structure and to the typical character-
istics of the modulated signal.

1.2 General considerations

The trasmitting chain of a DVB-T transmitter can be sketched by functional blocks
with the aim to adapt the baseband TV signals from the output of the MPEG-
2 transport multiplexer, to the terrestrial channel characteristics (see figure 1.1).
The system is designed to be directly compatible with MPEG-2 coded TV signals
(ISO/IEC 13818 )[5].

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1.2 – General considerations

Figure 1.1. Functional block diagram of a DVB-T transmitter

Since the system is being designed for digital terrestrial television services to
operate within the existing VHF (Very High Frequency) and UHF (Ultra High Fre-
quency) spectrum allocation for analogue transmissions, it is required that the Sys-
tem provides sufficient protection against high levels of Co-Channel Interference
(CCI) and Adjacent Channel Interference (ACI) emanating from existing PAL/SECAM/NTSC
services. It is also a requirement that the System allows the maximum spectrum effi-
ciency when used within the VHF and UHF bands; this requirement can be achieved
by utilizing Single Fequency Network (SFN) operation.
To allow optimal trade off between network topology and frequency efficiency,
a flexible guard interval is specified. This enable the system to support different
network configurations, such as large area SFN and single transmitter, while keeping
maximum frequency efficiency.
Furthermore the standard [4] specifies two transmission modes. The 2K mode
is suitable for single transmitter operation and for small SFN networks with limited
transmitter distances. The 8K mode can be used both for single transmitter oper-
ation and for small and large SFN networks. Exclusively for use in Digital Video
Broadcasting-Handheld (DVB-H) systems, a third transmission mode is defined 4K.
This additional trasmission mode permits to offer an additional trade-off between

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transmission cell size and mobile reception capabilities, providing an additional de-
gree of flexibility for DVB-H network planning.
The system allows different levels of QAM modulation and different inner code
rates. The system also allows two level hierarchical channel coding and modulation,
including uniform and multi-resolution constellation. In this case the functional
block diagram of the system shall be expanded to include the modules shown dashed
in figure 1.1. Two independent MPEG transport streams, referred to as the high-
priority and the low-priority stream, are mapped onto the signal constellation by the
mapper and the modulator which therefore has a corresponding number of inputs.

1.3 Channel coding

The first five functional blocks have the channel coding task. These blocks are:

• Transport multiplex adaptation and randomization for energy dispersal;

• Outer coding;

• Outer interleaver;

• Inner coder;

• Inner interleaver.

Afterwards will be given a detailed description of each single block operation.

1.3.1 Transport multiplex adaptation and randomization for

energy dispersal
The System input stream shall be organized in fixed length packets coming from the
MPEG-2 transport multiplexer. The total packet length of the MPEG-2 transport
multiplex (MUX) packet is 188 bytes (figure 1.2).

Figure 1.2. MPEG-2 transport multiplexer packet

These packets are composed by 1 sync-word byte SYNC (47HEX ) and 187 data
bytes.

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1.3 – Channel coding

Figure 1.3. Scrambler/descrambler schematic diagram

This data stream is randomized using a scrambler-descrambler, depicted in fig-

ure 1.3. Scrambler-descrambler uses a Pseudo Random Binary Sequence (PRBS)
generator, and the polynomial for the generator is given by

1 + X 14 + X 15 . (1.1)

The PRBS register is initiated at the start of every eight transport packets load-
ing into it the initialization sequence 100101010000000. To provide an initialization
signal for the descrambler, the MPEG-2 sync byte of the first transport packet in a
group of eight packets is bit-wise inverted from 47HEX to B8HEX (figure 1.4).

Figure 1.4. Randomized transport packets

The first bit at the output of the PRBS generator shall be applied to the first
bit of the first byte following the inverted MPEG-2 sync byte. To aid other synchro-
nization functions, during the MPEG-2 sync bytes of the subsequent seven transport
packets, the PRBS generation shall continue, but its output shall be disabled, leav-
ing these bytes unrandomized. Thus, the period of the PRBS sequence shall be 1503
bytes.

1.3.2 Outer coding

The outer coding and interleaving is performed by a Reed-Solomon RS(204,188,t =
8) shortned code. This code is applied to each randomized transport packet of 188
bytes, generating an error protected packet 204 bytes long, consisting of 188 data

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bytes and 16 parity bytes, allowing to correct up to 8 random erroneous bytes in

a received word of 204 bytes (figure 1.5). The shortened Reed-Solomon code is

Figure 1.5. Reed-Solomon RS(204,188,t = 8) error protected packets

implemented by adding 51 bytes, all set to zero, before the information bytes at the
input of an RS (255,239, t = 8) encoder. After the RS coding procedure these null
bytes are discarded, leading to a RS code word of 204 bytes length.

1.3.3 Outer interleaver

In this function block the interleaver sketched in figure 1.6 is applied to the error pro-
tected packets. The interleaver is composed of I = 12 branches, cyclically connected
to the input byte-stream by the input switch. Each branch j contains a First-In,
First-Out (FIFO) shift register, with depth j ∗ M cells where M = 17 = N/I,
N = 204. The cells of the FIFO contains 1 byte, and the input and output switches
are synchronized.

Figure 1.6. Conceptual diagram of the outer interleaver and deinterleaver

1.3.4 Inner coding

This coder uses a punctured convolutional code, based on a mother convolutional
code of rate 1/2 with 64 states. This allows to selection the most appropriate
level of error correction for a given service or data rate in either non-hierarchical

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1.3 – Channel coding

or hierarchical transmission mode. The generator polynomials of the mother code

are G1 = 171OCT = 1111001BIN for X output and G2 = 133OCT = 1011011BIN for Y
output (figure 1.7). If two level hierarchical transmission is used, each of the two

Figure 1.7. The mother convolutional code of rate 1/2

parallel channel encoders can have its own code rate.

In addition to the mother code of rate 1/2 the system shall allow punctured rates
of 2/3, 3/4, 5/6 and 7/8, as represented in table 1.1.

Table 1.1. Puncturing pattern and transmitted sequence after parallel-to-serial

conversion for the possible code rates

Code Rates r Puncturing pattern Transmitted sequence

(after parallel-to-serial conversion)
1/2 X: 1 X1 Y1
Y: 1
2/3 X: 1 0 X1 Y1 Y 2
Y: 1 1
3/4 X: 1 0 1 X1 Y1 Y 2 X3
Y: 1 1 0
5/6 X: 1 0 1 0 1 X1 Y1 Y 2 X3 Y4 X 5
Y: 1 1 0 1 0
7/8 X: 1 0 0 0 101 X1 Y1 Y 2 Y3 Y4 X 5 Y6 X7
Y: 1 1 1 1 010

1.3.5 Inner interleaver

As depicted in figure 1.8, the inner interleaver is consisted of a bit-wise interleaver,
followed by a symbol interleaver. Both the interleaving processes are block-based.

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Figure 1.8. Inner interleaver: a) non-hierarchical transmission mode, b) hierar-

chical transmission mode

Bit-wise interleaver

The input of this block, which consists of up to two bit streams, is demultiplexed into
v sub-streams, where v = 2 for QPSK, v = 4 for 16-QAM, and v = 8 for 64-QAM.
In non-hierarchical transmission mode, the single input stream is demultiplexed
into v sub-streams. In hierarchical transmission mode, the high priority stream is
demultiplexed in two sub-streams and the low priority stream is demultiplexed into
v − 2 sub-streams.
The demultiplexer has to map the input bits xdi onto output bits be,do , following
these rules:

• Non-hierarchical transmission mode

xdi = b[di(mod)v](div)(v/2)+2[di(mod)(v/2)],di(div)v (1.2)

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• Hierachical transmission mode

x0 di = bdi(mod)2,di(div)2
00 (1.3)
x di = b[di(mod)(v−2)](div)((v−2)/2)+2[di(mod)((v−2)/2)]+2,di(div)(v−2)

where:
- xdi is the input to the demultiplexer in non-hierarchical mode;
- x0di is the high priority input to the demultiplexer;
- x00di is the low priority input, in hierarchical mode;
- di is the input bit number;
- be,do is the output from the demultiplexer;
- e is the demultiplexed bit stream number (0 ≤ e < v);
- do is the bit number of a given stream at the output of the demultiplexer;
- mod is the integer modulo operator;
- div is the integer division operator.

Each sub-stream from the demultiplexer is processed by a separate bit interleaver.

There are therefore up to six interleavers depending on v, labelled I0 to I5. Each of
these interlevers works on a block size of 126 bits, but the interleaving sequence is
different in each case. The block interleaving process is therefore repeated exactly
twelve times per OFDM symbol of useful data in the 2K mode and forty-eight times
per symbol in the 8K mode.
For each bit interleaver, the input bit vector is defined by:

B(e) = (be,0 ,be,1 ,be,2 , . . . ,be,125 ) (1.4)

where e ranges from 0 to v − 1.

The interleaved output vector A(e) = (ae,0 ,ae,1 ,ae,2 , . . . ,ae,125 ) is defined by:

ae,w = be,He (w) w = 0,1,2, . . . ,125 (1.5)

where He (w) is a permutation function which is different for each interleaver, defined
in table 1.2.
The outputs of the v bit interleavers are grouped to form the digital data symbols,
such that each symbol of v bits will consist of exactly one bit from each of the v
interleavers. Hence, the output from the bit-wise interleaver is a v bit word y 0 , that
has the output of I0 as its most significant bit:

y 0 w = (a0,w ,a1,w , . . . ,av−1,w ) (1.6)

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Table 1.2. Bit-wise interleaver permutation function

I0 H0 (w) = w
I1 H1 (w) = (w + 63)mod126
I2 H2 (w) = (w + 105)mod126
I3 H3 (w) = (w + 42)mod126
I4 H4 (w) = (w + 21)mod126
I5 H5 (w) = (w + 84)mod126

Symbol interleaver
The purpose of the symbol interleaver is to map the v bit word onto the 1512 (2K
mode) or 6048 (8K mode) active carriers per OFDM symbol.
Thus in the 2K mode, 12 groups of 126 data words from the bit interleaver are
0
read sequentially into a vector Y 0 = (y00 ,y10 ,y20 , . . . ,y1511 ). Similarly in the 8K mode,
0 0 0 0 0
a vector Y = (y0 ,y1 ,y2 , . . . ,y6047 ) is assembled from 48 groups of 126 data words.
The interleaved vector Y = (y0 ,y1 ,y2 , . . . ,yNmax −1 ) is defined by:

yH(q) = yq0 for even symbols for q = 0, . . . ,Nmax − 1

0 (1.7)
yq = yH(q) for odd symbols for q = 0, . . . ,Nmax − 1

where Nmax = 1512 in the 2K mode and Nmax = 6048 in the 8K mode, and H(q) is
the permutation function defined by the following.
Let an (Nr − 1) bit binary word Ri0 is defined, with Nr = log2 Mmax , where
Mmax = 2048 in the 2K mode and Mmax = 8192 in the 8K mode, taking the
following values: a vector Ri is derived by the vector Ri0 by the it permutation

i = 0,1: Ri0 [Nr − 2,Nr − 3, · · · ,1,0] = 0,0, · · · ,0,0

i = 2: Ri0 [Nr − 2,Nr − 3, · · · ,1,0] = 0,0, · · · ,0,1
2 < i < Mmax {Ri0 [Nr − 3,Nr − 3, · · · ,1,0] = Ri−1
0
[Nr − 2,Nr − 3, · · · ,2,1]
0 0 0
in the 2K mode: Ri [9] = Ri−1 [0] ⊕ Ri−1 [3]
0 0 0 0 0
in the 8K mode: Ri [11] = Ri−1 [0] ⊕ Ri−1 [1] ⊕ Ri−1 [4] ⊕ Ri−1 [6]}

defined in table 1.3 and in table 1.4.

Table 1.3. Bit permutations for 2K mode

Ri0 bit positions 9 8 7 6 5 4 3 2 1 0

Ri bit positions 0 7 5 1 8 2 6 9 3 4

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1.3 – Channel coding

Table 1.4. Bit permutations for 8K mode

Ri0 bit positions 11 10 9 8 7 6 5 4 3 2 1 0

Ri bit positions 5 11 3 0 10 8 6 9 2 4 1 7

The permutation function H(q) is defined by the following algorithm:

q=0
for(i = 0; i < Mmax ; i = i + 1)
N
X r −2

{H(q) = (imod2)2 Nr −1
+ Ri [j]2j ;
j=0
if(H(q) < Nmax ) q = q + 1;}

In similar way to y 0 , y is made up of v bits:

yq0 = (y0,q0 ,y1,q0 , . . . ,yv−1,q0 ) (1.8)

where q 0 is the symbol number at the output of the symbol interleaver. These values
of y are used to map the data into the signal constellation, as described in the next
paragraph.

1.3.6 Signal constellation and mapping

As said previous the system uses ODFM transmission. All data carriers in one
OFDM frame are modulated using either QPSK, 16-QAM, 64-QAM, non-uniform
16-QAM or non-uniform 64-QAM constellations (see the examples in figure 1.9).
All constellations are made using the Gray mapping.
The exact proportions of the constellations depend on the parameter α, which can
take three values 1,2,or 4. α is the minimum distance separating two constellation
points carrying different HP-bit values divided by the minimum distance separating
any two constellation points.
The exact values of the constellation points are z ∈ {n + jm} with values of n,
m given below for the various constellations:
• QPSK
n ∈ {−1,1}, m ∈ {−1,1}
• 16-QAM (uniform and non-uniform with α = 1)
n ∈ {−3, − 1,1,3}, m ∈ {−3, − 1,1,3}
• non-uniform 16-QAM with α = 2

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Figure 1.9. Constellation examples: a) uniform 16-QAM or non-uniform 16-QAM

with α = 1, b) non-uniform 16-QAM with α = 2, c) non-uniform 16-QAM with
α=4

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1.4 – OFDM frame structure

n ∈ {−4, − 2,2,4}, m ∈ {−4, − 2,2,4}

• non-uniform 16-QAM with α = 4
n ∈ {−6, − 4,4,6}, m ∈ {−6, − 4,4,6}
• 64-QAM (uniform and non-uniform with α = 1)
n ∈ {−7, − 5, − 3, − 1,1,3,5,7}, m ∈ {−7, − 5, − 3, − 1,1,3,5,7}
• non-uniform 64-QAM with α = 2
n ∈ {−8, − 6, − 4, − 2,2,4,6,8}, m ∈ {−8, − 6, − 4, − 2,2,4,6,8}
• non-uniform 64-QAM with α = 4
n ∈ {−10, − 8, − 6, − 4,4,6,8,10}, m ∈ {−10, − 8, − 6, − 4,4,6,8,10}

Non-hierarchical transmission
The data stream at the output of the inner interleaver consists of v bit words, that
are mapped onto a complex number z, in according to one of the three uniform
constellations described above.

Hierarchical transmission
In the case of hierarchical transmission, the data streams are formatted as shown in
figure 1.8 b), and then the used constellations are only that non-uniform ones.
In particular in this case the high priority bits are the first two bits of the inner
interleaver output word (y0,q0 ,y1,q0 ). Thanks to the Gray mapping, all the symbols
located in a quadrant have the same two first bits. For these reason in reception
they can be easily decoded using a QPSK demapper. Instead to decode the low
priority bits, the full constellation shall be examined.

1.4 OFDM frame structure

The transmitted signal is organized in frames. Each frame consists of 68 OFDM
symbols. Four frames constitute one super-frame. Each symbol is constituted by a
set of K = 6817 carriers in the 8K mode and K = 1705 carriers in the 2K mode,
and transmitted with a duration TS . It is composed of two parts: a useful part with
duration TU and a guard interval with duration ∆. The guard interval consists in a
cyclic continuation of the useful part, TU , and is inserted before it. Four values of
guard intervals may be used according to table 1.6.
The symbols in an OFDM frame are numbered from 0 to 67. All symbols contain
data and reference information, that are modulated with a different modulation
scheme respect to the data. For these reasons, each symbol can be considered to be
divided in cells, each corresponding to the modulation carried on one carrier during
one symbol.
In addition to the transmitted data an OFDM frame contains:

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- scattered pilot cells;

- continual pilot cells;
- TPS carriers.

The pilots can be used for frame synchronization, frequency synchronization, time
synchronization, channel estimation, transmission mode identification and can also
be used to follow the phase noise.
The carriers are indexed by k ∈ [Kmin ; Kmax ] and determined by Kmin = 0 and
Kmax = 1704 in 2K mode and 6816 in 8K mode respectively. The spacing between
adjacent carriers is 1/TU while the spacing between carriers Kmin and Kmax are
determined by (K − 1)/TU .
The numerical values for the OFDM parameters for the 8K and 2K modes are given
in table 1.5 and table 1.6 for 8 MHz channels. The values for the various time-related
parameters are given in multiples of the elementary period T and in microseconds.
The elementary period T is 7/64 µs for 8 MHz channels, 1/8 µs for 7 MHz channels,
7/48 µs for 6 MHz channels and 7/40 µs for 5 MHz channels.

Table 1.5. Numerical values for the OFDM parameters for the 8K and 2K modes
for 8 MHz channels

Parameter 8K mode 2K mode

Number of carriers K 6817 1705
Value of carrier number Kmin 0 0
Value of carrier number Kmax 6816 1704
Duration TU [µs] 896 224
Carrier spacing 1/TU [Hz] 1116 4464
Spacing between carriers Kmin and Kmax (K − 1)/TU [Hz] 7607143 7607143

Table 1.6. Duration of symbol part for the allowed guard intervals for 8 MHz
channels
Mode 8K mode 2K mode
Guard Interval 1/4 1/8 1/16 1/32 1/4 1/8 1/16 1/32
∆/TU
Duration of symbol 8192×T 2048×T
part TU 896 224
Duration of guard 2048×T 1024×T 512×T 256×T 512×T 256×T 128×T 64×T
interval ∆ [µs] 224 112 56 28 56 28 14 7
Symbol duration 10240×T 9216×T 8704×T 8448×T 2560×T 2304×T 2176×T 2112×T
TS = ∆ + TU [µs] 1120 1008 952 924 280 252 238 231

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1.4 – OFDM frame structure

The emitted signal is described by the following expression:

( ∞ X
67 K
)
X X max

s(t) = Re ej2πfc t cm,l,k × Ψm,l,k (t) (1.9)

m=0 l=0 k=Kmin

where
( 0
j2π k (t−∆−lTS −68mTS )
e TU (l + 68m)TS ≤ t ≤ (l + 68m + 1)TS
Ψm,l,k (t) = (1.10)
0 else

where:
- k denotes the carrier number;
- l denotes the OFDM symbol number;
- m denotes the transmission frame number;
- K is the number of transmitted carriers;
- TS is the symbol duration;
- TU is the inverse of the carrier spacing;
- ∆ is the duration of the guard interval;
- fc is the central frequency of the RF signal;
- k 0 is the carrier index relative to the center frequency, k 0 = k−(Kmax +Kmin )/2;
- cm,l,k is the complex symbol for carrier k of the OFDM symbol number l in
frame number m.

There is a clear resemblance between this and the Inverse Discrete Fourier Trans-
form (IDFT):
N −1
1 X
xn = Xq ej2πnq/N (1.11)
N q=0

Since various efficient Fast Fourier Transform algorithms exist to perform the DFT
and its inverse, it is a convenient form of implementation to use the Inverse FFT
(IFFT) in a DVB-T modulator to generate N samples xn corresponding to the useful
part, TU long, of each symbol. The guard interval is added by taking copies of the
last N ∆/TU of these samples and appending them in front.
The cm,l,k values are normalized modulation values of the constellation point z
according to the modulation alphabet used for the data. The normalization factors
yield E[c × c∗ ] = 1 and are shown in table 1.7.

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Table 1.7. Normalization factor for data symbols

Modulation scheme Normalization

√ factor
2
QPSK c = z/√ 2
2
16-QAM α=1 c = z/√ 10
2
α=2 c = z/√20
2
α=4 c = z/√ 52
2
64-QAM α=1 c = z/√42
α=2 c = z/√2 60
α=4 c = z/ 2 108

1.5 Reference signals

Various cells within the OFDM frame are modulated with reference information
whose transmitted value is known to the receiver. Cells containing reference infor-
mation are transmitted at “boosted” power level, i.e. E[c × c∗ ] = 16/9. These cells
are scattered or continual pilot cells.
Each continual pilot coincides with a scattered pilot every fourth symbol; the
number of useful data carriers is constant from symbol to symbol: 1512 useful car-
riers in 2K mode and 6048 useful carriers in 8K mode. The continual and scattered
pilots are modulated according to a Pseudo Random Binary Sequence (PRBS), wk ,
corresponding to their respective carrier index k. This sequence is generated in
according to figure 1.10.

Figure 1.10. Generation of PRBS sequence

The PRBS is initialized so that the first output bit from the PRBS coincides
with the first active carrier. A new value is generated by the PRBS on every used
carrier (whether or not it is a pilot).

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1.5 – Reference signals

The polynomial for the Pseudo Random Binary Sequence (PRBS) generator shall
be:
X 11 + X 2 + 1. (1.12)

1.5.1 Location of scattered pilot cells

As said previous, scattered pilot cells are always transmitted at the “boosted” power
level. Thus the corresponding modulation is given by:

Re {cm,l,k } = 4/3 × 2(1/2 − wk )

(1.13)
Im {cm,l,k } = 0

For the symbol of index l (ranging from 0 to 67), carriers for which index k
belongs to the subset {k = Kmin + 3(lmod4) + 12p | p ∈ N, p ≥ 0,k ∈ [Kmin ; Kmax ]}
are scattered pilots.
The pilot insertion pattern is shown in figure 1.11.

Figure 1.11. Location of scattered pilot cells • = scattered pilot, ◦ = data

1.5.2 Location of continual pilot cells

In addition to the scattered pilots described above, 177 continual pilots in the 8K
mode and 45 in the 2K mode, are inserted according to table 1.8. Continual means
that they occur on all symbols.
All continual pilots are modulated according to the reference sequence, and trans-
mitted at “boosted” power level, using this modulation rule:

Re {cm,l,k } = 4/3 × 2(1/2 − wk )

(1.14)
Im {cm,l,k } = 0.

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Table 1.8. Carrier indices for continual pilot carriers

2K mode 8K mode
0 48 54 87 141 156 192 0 48 54 87 141 156 192
201 255 279 282 333 432 450 201 255 279 282 333 432 450
483 525 531 618 636 714 759 483 525 531 618 636 714 759
942 969 984 1050 1101 1107 1110 942 969 984 1050 1101 1107 1110
1137 1140 1146 1206 1269 1323 1377 1137 1140 1146 1206 1269 1323 1377
1491 1683 1704 1491 1683 1704 1752 1758 1791 1845
1860 1896 1905 1959 1983 1986 2037
2136 2154 2187 2229 2235 2322 2340
2418 2463 2469 2484 2508 2577 2592
2622 2643 2646 2673 2688 2754 2805
2811 2814 2841 2844 2850 2910 2973
3027 3081 3195 3387 3408 3456 3462
3495 3549 3564 3600 3609 3663 3687
3690 3741 3840 3858 3891 3933 3939
4026 4044 4122 4167 4173 4188 4212
4281 4296 4326 4347 4350 4377 4392
4458 4509 4515 4518 4545 4548 4554
4614 4677 4731 4785 4899 5091 5112
5160 5166 5199 5253 5268 5304 5313
5367 5391 5394 5445 5544 5562 5595
5637 5643 5730 5748 5826 5871 5877
5892 5916 5985 6000 6030 6051 6054
6081 6096 6162 6213 6219 6222 6249
6252 6258 6318 6381 6435 6489 6603
6795 6816

1.6 Transmission Parameter Signalling (TPS)

The TPS carriers are used for the purpose of signalling parameters related to the
transmission scheme, i.e. to channel coding and modulation. The TPS is trans-
mitted in parallel on 17 TPS carriers for the 2K mode and on 68 carriers for the
8K mode. Every TPS carrier in the same symbol conveys the same differentially
encoded information bit. The carrier indices containing TPS carriers are listed in
table 1.9.
The TPS is defined over 68 consecutive OFDM symbols, referred to as one OFDM
frame. The reference sequence corresponding to the TPS carriers of the first symbol
of each OFDM frame are used to initialize the TPS modulation on each TPS carrier.
Each OFDM symbol conveys one TPS bit. Each TPS block (corresponding to one
OFDM frame) contains 68 bits, defined as follows:
- 1 initialization bit;
- 16 synchronization bits;

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1.6 – Transmission Parameter Signalling (TPS)

Table 1.9. Carrier indices for TPS carriers

2K mode 8K mode
34 50 209 346 413 34 50 209 346 413 569 595
569 595 688 790 901 688 790 901 1073 1219 1262 1286
1073 1219 1262 1286 1469 1469 1594 1687 1738 1754 1913 2050
1594 1687 2117 2273 2299 2392 2494 2605 2777
2923 2966 2990 3173 3298 3391 3442
3458 3617 3754 3821 3977 4003 4096
4198 4309 4481 4627 4670 4694 4877
5002 5095 5146 5162 5321 5458 5525
5681 5707 5800 5902 6013 6185 6331
6374 6398 6581 6706 6799

- 37 information bits;
- 14 redundancy bits for error protection.

Of the 37 information bits, 31 are used. The remaining 6 bits shall be set to zero.

1.6.1 TPS transmission format

The transmission parameter information shall be transmitted as shown in table 1.10.

Table 1.10. TPS signalling information and format

Bit number Purpose/Content

s0 Initialization
s1 to s16 Synchronization word
s17 to s22 Length indicator (see appendix A)
s23 , s24 Frame number
s25 , s26 Constellation
s27 , s28 , s29 Hierarchy information (see appendix A)
s30 , s31 , s32 Code rate, HP stream
s33 , s34 , s35 Code rate, LP stream
s36 , s37 Guard interval
s38 , s39 Transmission mode (see appendix A)
s40 to s47 Cell identifier
s48 to s53 all set to “0” see appendix A
s54 to s67 Error protection

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The TPS information transmitted in super-frame m0 bits s25 -s39 always apply to
super-frame m0 + 1, whereas all other bits refer to super-frame m0 .

Initialization
The first bit, s0 , is an initialization bit for the differential 2-PSK modulation.

Synchronization
Bits 1 to 16 of TPS makes a synchronization word.
The first and third TPS block in each super-frame have the following synchronization
word:

s1 -s16 = 0011010111101110.

The second and fourth TPS block have the following synchronization word:

s1 -s16 = 1100101000010001.

TPS length indicator

The first 6 bits of the TPS information are used as a TPS length indicator (is the
binary count of TPS information bits starting from and including bit s17 to s47 ) to
signal the number of used bits of the TPS.
This field is indispensable beacuse in DVB-T the transmission of the Cell Identifi-
cation is optional. The TPS length indicator carries then the values:
- “010111” when Cell Identification information is not transmitted (23 TPS bits
in use);
- “011111” when Cell Identification information is transmitted (31 TPS bits in
use).

Frame number
As said previous, 4 frames constitute one super-frame and the frames inside the
super-frame are numbered from 1 to 4. For this reason a 2 bits field in TPS block
is used to transmit the frame number as specified in table 1.11.

Constellation
The constellation shall be signalled by 2 bits field according to table 1.12. In order
to determine the modulation scheme, the receiver shall also decode the hierarchy
information given in table 1.13.

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1.6 – Transmission Parameter Signalling (TPS)

Table 1.11. Signalling format for frame number

Bits s23 , s24 Frame number

00 Frame number 1 in the super-frame
01 Frame number 2 in the super-frame
10 Frame number 3 in the super-frame
11 Frame number 4 in the super-frame

Table 1.12. Signalling format for the possible constellation patterns

Bits s25 , s26 Constellation characteristics

00 QPSK
01 16-QAM
10 64-QAM
11 Reserved

Hierarchy information
The hierarchy information specifies whether the transmission is hierarchical and, if
so, what the α value is used. These information are signalled by three bits according
to table 1.13.

Table 1.13. Signalling format for the α values

Bits s27 , s28 , s29 α value

000 Non-hierarchical
001 α=1
010 α=2
011 α=4
100 See appendix A
101 See appendix A
110 See appendix A
111 See appendix A

Code rates
HP stream and LP stream code rates are transmitted using the six bits from s30
to s35 in according to table 1.14. In case of non-hierarchical channel coding and
modulation requires signalling of one code rate r. In this case, three bits specifying

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the code rate as shown in table 1.14 are followed by another three bits of value 000.

Table 1.14. Signalling format for each of the code rates

Bits Code rate

s30 , s31 , s32 (HP stream)
s33 , s34 , s35 (LP stream)
000 1/2
001 2/3
010 3/4
011 5/6
100 7/8
101 reserved
110 reserved
111 reserved

Guard intervals
The value of the guard interval is signalled according to table 1.15.

Table 1.15. Signalling format for each of the guard interval values

Bits s36 , s37 Guard interval values (∆/TU )

00 1/32
01 1/16
10 1/8
11 1/4

Transmission mode
Two bits are used to signal the transmission mode (2K mode or 8K mode).

Cell identifier
The eight bits s40 -s47 are used to identify the cell from which the signal comes from.
The most significant byte of the cell id, i.e. b15 -b8 , shall be transmitted in super-
frames with the frame number 1 and 3. The least significant byte of the cell id, i.e.
b7 -b0 , shall be transmitted in super-frames with the frame number 2 and 4. The

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1.6 – Transmission Parameter Signalling (TPS)

Table 1.16. Signalling format for transmission mode

Bits s38 , s39 Transmission mode

00 2K mode
01 8K mode
10 see appendix A
11 reserved

mapping of bits is according to table 1.17. If the transmission of the cell id is not
foreseen the eight bits shall be set to zero.

Table 1.17. Mapping of the cell id on the TPS bits

TPS bit number Frame number 1 or 3 Frame number 2 or 4

s40 cell id b15 cell id b7
s41 cell id b14 cell id b6
s42 cell id b13 cell id b5
s43 cell id b12 cell id b4
s44 cell id b11 cell id b3
s45 cell id b10 cell id b2
s46 cell id b9 cell id b1
s47 cell id b8 cell id b0

Error protection of TPS

The 53 bits containing the TPS synchronization and information (bits s1 -s53 ) are
extended with 14 parity bits of the BCH(67,53,t = 2) shortened code, derived from
the original systematic BCH(127,113,t = 2) code. The code generator polynomial
is:
h(x) = x14 + x9 + x8 + x6 + x5 + x4 + x2 + x + 1. (1.15)
The shortened BCH code may be implemented by adding 60 bits, all set to zero,
before the information bits input of an BCH(127,113,t = 2) encoder. After the BCH
encoding these null bits shall be discarded, leading to a BCH code word of 67 bits.

1.6.2 TPS modulation

As said previous, every TPS carrier is DBPSK modulated and conveys the same
message. The DBPSK is initialized at the beginning of each TPS block.

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The rule used for differential modulation of the carrier k of the OFDM symbol l
(l > 0) in frame m is:

Re {cm,l,k } = Re {cm,l−1,k } ; Im {cm,l,k } if sl =0

(1.16)
Re {cm,l,k } = −Re {cm,l−1,k } ; Im {cm,l,k } if sl =1

The absolute modulation of the TPS carriers in the first symbol in a frame is derived
from the reference sequence wk as follows:

Re {cm,l,k } = 2(1/2 − wk )
(1.17)
Im {cm,l,k } = 0

1.7 DVB-T system parameter summary and net

data rate
In summary, the following parameters can be chosen in the DVB-T system:
- code rate of inner error protection(1/2, 2/3, 3/4, 5/6, 7/8);
- carrier modulation (QPSK ⇒ 2 bits per carrier; 16-QAM ⇒ 4 bits; 64-QAM
⇒ 6 bits);
- guard interval length (1/4, 1/8, 1/16, 1/32);
- modulation parameter α (1, 2, 4);
- FFT length; number of carriers (2k ⇒ 1705 carriers; 8k ⇒ 6817 carriers).

The net bit rate depends on the code rate of the inner error correction, the
method of the carrier modulation and the chosen guard interval length. In table 1.18
is summarized all possible net data rates in the DVB-T system. The net date rates
are calculated from the following formula [6]:

RU = RS × v × CRI × CRRS × (TU /TS ) (1.18)

where:
- RU is the useful net data rate (Mbit/s);
- RS is the symbol rate, 6.75 Msymbols/s;
- v is the number of bit per carrier;
- CRI is the inner code rate;
- CRRS is the Reed Solomon code rate, 188/204;
- TU is the duration of (useful) symbol part;
- TS is the symbol duration, including guard interval.

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1.8 – Spectrum characteristics

Table 1.18. Net data rates in the DVB-T system (in Mbit/s)

∆/TU
Modulation v CRI 1/4 1/8 1/16 1/32
QPSK 2 1/2 4.98 5.53 5.85 6.03
2 2/3 6.64 7.37 7.81 8.04
2 3/4 7.46 8.29 8.78 9.05
2 5/6 8.29 9.22 9.76 10.05
2 7/8 8.71 9.68 10.25 10.56
16-QAM 4 1/2 9.95 11.06 11.71 12.06
4 2/3 13.27 14.75 15.61 16.09
4 3/4 14.93 16.59 17.56 18.10
4 5/6 16.59 18.43 19.52 20.11
4 7/8 17.42 19.35 20.49 21.11
64-QAM 6 1/2 14.93 16.59 17.56 18.10
6 2/3 19.91 22.12 23.42 24.13
6 3/4 22.39 24.88 26.35 27.14
6 5/6 24.88 27.65 29.27 30.16
6 7/8 26.13 29.03 30.74 31.67

1.8 Spectrum characteristics

The OFDM symbols are constituted by a juxtaposition of equally-spaced orthogonal
carriers. The amplitudes and phases of the data cell carriers are varying symbol by
symbol according to the mapping process described previous.
Each carrier is situated at frequency:

k
fk = fc + ; (1.19)
TU

and has a power spectral density Pk (f ) defined by the following expression:

 2
sin π(f − fk )TS
Pk (f ) = . (1.20)
π(f − fk )TS

The overall power spectral density (PSD) of the modulated data cell carriers is
the sum of the power spectral densities of all these carriers. A theoretical DVB
transmission signal spectrum is illustrated in figure 1.12 (for 8 MHz channels).

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Figure 1.12. Theoretical DVB transmission signal spectrum for guard interval
∆ = TU /4 (for 8 MHz channels)

1.9 Time-domain signal characteristics

How it is possible to see in figure 1.13 the DVB-T signal in time-domain exhibits a
noise-like characteristic, this is a OFDM signals typical feature. In general this kind
of signals present high crest factor cf and DVB-T signal isn’t an exception [3]. The
crest factor is defined as:  
U
cf = 20log10 (1.21)
Û
where U is the maximum peak voltage and Û is the root mean square rms voltage.
Because the OFDM signals is composed by a sum of modulated signals, the
maximum peak voltage is obtained by adding together the peak amplitudes of all
single carriers:
N
X −1
U= Uk (1.22)
k=0

where N is the total number of modulated carriers in a OFDM symbol, and Uk is

the maximum peak voltage of the carrier k. If all carriers have the same maximum

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1.9 – Time-domain signal characteristics

Figure 1.13. Time-domain DVB-T signal for guard interval ∆ = TU /4 and 64-
QAM modulation scheme

peak voltage, i.e. QPSK, the relation 1.22 becomes:

U = N U0 . (1.23)
In the same manner, the rms value of an OFDM signal is calculated from the
quadratic mean as: v
uN −1
uX 2
2
Û = t Uˆk (1.24)
k=0

where Uˆk is the rms value of the carrier k of a OFDM symbol. If all carriers have
the same maximum peak voltage, i.e. QPSK, the relation 1.24 can be written as:
r
U0 2
q
2 2 2
Û = N Û0 = N . (1.25)
2
After these considerations, the cf of a OFDM signal is
 
N U0  √ 
2
cf = 20log10  q = 20log10 2N = 10log10 (2N ) . (1.26)
2 U0 2
N 2

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The theoretical cf in DVB-T are then

(
35 dB in 2K mode with 1705 carries used
cf = (1.27)
41 dB in 8K mode with 6817 carries used.

Even though the theoretical cf is very high, the cf of a real DVB-T signal is limited
to about 11-12 dB before the signal is fed into the power amplifier. This limitation is
necessary because any practical power amplifier can’t operate with high cf without
causing its destruction.

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Appendix A

Additional features for DVB

Handheld terminals (DVB-H)

A.1 Introduction
Although the DVB-T transmission system has proven its ability to serve fixed,
portable and mobile terminals, handheld terminals (defined as a light battery pow-
ered apparatus) require specific features from the transmission system serving them:
• as battery powered, the transmission system shall offer them the possibility to
repeatedly power off some part of the reception chain to increase the battery
usage duration;
• as targeting nomadic users, the transmission system shall ease access to the
DVB-H services when receivers leave a given transmission cell and enter a new
one;
• as expected to serve various situations of use (indoor and outdoor, pedestrian
and inside moving vehicle), the transmission system shall offer sufficient flex-
ibility / scalability to allow reception of DVB-H services at various speeds,
while optimizing transmitter coverage.

To overcome these problems the following processes variant are implemented, as

depicted in figure A.1:
- Orthogonal Frequency Division Multiplexing (OFDM) transmission: an addi-
tional 4K mode is provided with the implied reference signals and Transmission
Parameter Signalling (TPS);
- Inner interleaving: a native inner interleaver for the 4K transmission mode
is provided as well as an in-depth symbol interleaver to be used with the 2K
or 4K modes. Also, the implied Transmission Parameter Signalling (TPS) is
defined;

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A – Additional features for DVB Handheld terminals (DVB-H)

- Signalling information: Transmission Parameter Signalling bits are defined

to signal to the receivers the use of Time-Slicing and / or MPE-FEC in the
DVB-H transmission.

Figure A.1. Functional block diagram of the additional features

This appendix describes additional features to DVB-T to support Handheld termi-

nals transmitting DVB-H services.

A.2 Channel coding and modulation

A.2.1 Inner interleaving
A native inner interleaver for the 4K mode as well as the option to use the 8K
inner interleaver onto the encoded bit-flows produced for the 2K and 4K modes are
specified in [4]. As illustrated in figure A.2, this option, called in-depth interleaver,
enlarge the depth of the inner interleaving to four consecutive OFDM symbols (2K)
or two consecutive OFDM symbols (4K).
As described in DVB-T, the inner interleaving consists of bit-wise interleaving
followed by symbol interleaving. Both the bit-wise interleaving and the symbol
interleaving processes are block-based.

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A.2 – Channel coding and modulation

Figure A.2. In-depth inner interleaver for 2K and 4K modes

Bit-wise interleaving
The block interleaving process, defined in paragraph 1.3.5, shall be repeated twenty-
four times per OFDM symbol in the 4K mode and when the in-depth interleaving
is applied in the 2K or 4K modes, either hierarchical or non-hierarchical, the block
interleaving process is repeated forty-eight times, thus providing the symbol inter-
leaver with the blocks of useful data needed to produce four consecutive 2K OFDM
symbols and two consecutive 4K OFDM symbols.

Native symbol interleaver

In the 4K mode, the purpose of the symbol interleaver is to map v bit words onto
the 3024 active carriers per OFDM symbol.
When the native 4K mode interleaver is implemented, the symbol interleaver acts
on blocks of 3024 data symbols. Thus in the in the 4K mode, 24 groups of 126 data
words from the bit interleaver are read sequentially into a vector Y 0 = (y00 ,y10 ,y20 , . . . ,y3023
0
).
The interleaved vector Y = (y0 ,y1 ,y2 , . . . ,yNmax −1 ) is defined by 1.7, where Nmax =
3024 and H(q) is the permutation function defined by the following.

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A – Additional features for DVB Handheld terminals (DVB-H)

Let an (Nr − 1) bit binary word Ri0 is defined, with Nr = log2 Mmax , where
Mmax = 4196, taking the following values: a vector Ri is derived by the vector Ri0

i = 0,1: Ri0 [Nr − 2,Nr − 3, · · · ,1,0] = 0,0, · · · ,0,0

i = 2: Ri0 [Nr − 2,Nr − 3, · · · ,1,0] = 0,0, · · · ,0,1
2 < i < Mmax 0
{Ri0 [Nr − 3,Nr − 3, · · · ,1,0] = Ri−1 [Nr − 2,Nr − 3, · · · ,2,1]
0 0 0
in the 4K mode: Ri [10] = Ri−1 [0] ⊕ Ri−1 [2]

by the it permutation defined in table A.1. The algorithm used to generate the

Table A.1. Bit permutations for 4K mode

Ri0 bit positions 10 9 8 7 6 5 4 3 2 1 0

Ri bit positions 7 10 5 8 1 2 4 9 0 3 6

permutation function is the same described in paragraph 1.3.5.

In-depth symbol interleavers

When the in-depth interleaver is selected in the 2K mode or 4K mode contexts, the
symbol interleaver acts on blocks of 6048 data symbols, whatever the mode. Thus,
0
a vector Y 0 = (y00 ,y10 ,y20 , . . . ,y6047 ) is assembled from 48 groups of 126 data words.
The interleaved vector Y = (y0 ,y1 ,y2 , . . . ,yNmax −1 ) is defined by:

yH(q) = yq0 for even interleaved vectors for q = 0, . . . ,Nmax − 1

0 (A.1)
yq = yH(q) for odd interleaved vectors for q = 0, . . . ,Nmax − 1

where Nmax = 6048 in the 2K mode and Nmax = 6048 in the 8K mode, and H(q) is
the permutation function defined for native 8K mode in paragraph 1.3.5.
In the 2K mode, interleaved vectors shall be mapped onto four consecutive
OFDM symbols. For even interleaved vectors these shall start with symbols 0,
8, 16, 24, etc. and for odd interleaved vectors these shall start with symbols 4, 12,
20, 28, etc. in every super-frame.
In the 4K mode, interleaved vectors shall be mapped onto two consecutive OFDM
symbols. For even interleaved vectors these shall start with symbols 0, 4, 8, 12, etc.
and for odd interleaved vectors these shall start with symbols 2, 6, 10, 14, etc. in
every super-frame.

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A.3 – OFDM frame structure

A.3 OFDM frame structure

For the 4K mode, each symbol is constituted by a set of K = 3409 carriers and
transmitted with a duration TS . It is composed of two parts: a useful part with
duration TU and a guard interval with duration ∆. The guard interval consists in a
cyclic continuation of the useful part, TU , and is inserted before it. Four values of
guard intervals may be used according to table A.3. For the 4K mode, the carriers
are indexed by k ∈ [Kmin ; Kmax ] and determined by Kmin = 0 and Kmax = 3408.
For the 4K mode, the numerical values for the OFDM parameters in 8 MHz channel
are given in table A.2 and table A.3.

Table A.2. Numerical values for the OFDM parameters for the 4K mode for
8 MHz channels

Parameter 4K mode
Number of carriers K 3409
Value of carrier number Kmin 0
Value of carrier number Kmax 3408
Duration TU [µs] 448
Carrier spacing 1/TU [Hz] 2232
Spacing between carriers Kmin and Kmax (K − 1)/TU [Hz] 7607143

Table A.3. Duration of symbol part for the allowed guard intervals for 8 MHz
channels
Mode 4K mode
Guard Interval 1/4 1/8 1/16 1/32
∆/TU
Duration of symbol 8192×T
part TU 896
Duration of guard 1024×T 512×T 256×T 128×T
interval ∆ [µs] 112 56 28 14
Symbol duration 5120×T 4608×T 4352×T 4224×T
TS = ∆ + TU [µs] 560 504 476 462

A.4 Reference signals

A.4.1 Location of continual pilot carriers
For the 4K mode, 89 continual pilots shall be inserted according to table A.4.

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A – Additional features for DVB Handheld terminals (DVB-H)

Table A.4. Carrier indices for continual pilot carriers

Continual pilots carrier positions for 4K mode

0 48 54 87 141 156 192
201 255 279 282 333 432 450
483 525 531 618 636 714 759
942 969 984 1050 1101 1107 1110
1137 1140 1146 1206 1269 1323 1377
1491 1683 1704 1752 1758 1791 1845
1860 1896 1905 1959 1983 1986 2037
2136 2154 2187 2229 2235 2322 2340
2418 2463 2469 2484 2508 2577 2592
2622 2643 2646 2673 2688 2754 2805
2811 2814 2841 2844 2850 2910 2973
3027 3081 3195 3387 3408

A.5 Transmission Parameter Signalling (TPS)

For the 4K mode, the TPS shall be transmitted in parallel on 34 TPS carriers and
shall be carried on the carrier having the indices presented in table A.5.

Table A.5. Carrier indices for TPS carriers

TPS carrier indices for 4K mode

34 50 209 346 413 569 595
688 790 901 1073 1219 1262 1286
1469 1594 1687 1738 1754 1913 2050
2117 2273 2299 2392 2494 2605 2777
2923 2966 2990 3173 3298 3391

A.5.1 TPS transmission format

When DVB-H signalling is performed, of the 37 information bits, 33 are used. The
remaining 4 bits shall be set to zero.
Options shown in table A.6 are specified in this appendix. The definitions for
the other signalling bits are given in the paragraph 1.6.

TPS length indicator

In DVB-H signal valid Cell Identification information shall be transmitted and the
value of the TPS length indicator shall be set to “100001” (33 TPS bits in use).

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A.5 – Transmission Parameter Signalling (TPS)

Table A.6. TPS signalling information and format

Bit number Purpose/Content

s17 to s22 Length indicator
s27 , s28 , s29 Hierarchy and Interleaving information
s38 , s39 Transmission mode
s48 to s49 DVB-H signalling
s50 to s53 all set to “0”

Hierarchy and Interleaving information

The bits s27 , s28 , s29 are used to signal if the in-depth interleaver is in use and if the
transmission is hierarchical.
The use of the in-depth interleaver for 2K or 4K transmission mode shall be signalled
using bit s27 as indicated in table A.7. When an 8K signal is transmitted only the
native interleaver shall be used.

Table A.7. Signalling format for in-depth inner interleaver

Bit s27 In-depth inner interleaver information

0 native interleaver
1 in-depth interleaver

Hierarchical transmission and, if so, the value of the α factor shall be signalled,
using bits s28 and s29 , in compliance with table A.8.

Table A.8. Signalling format for Hierarchy information

Bits s28 , s29 Hierarchy information

00 Non-hierarchical
01 α=1
10 α=2
11 α=4

Transmission mode

The transmission mode shall be signalled according to table A.9.

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A – Additional features for DVB Handheld terminals (DVB-H)

Table A.9. Signalling format for transmission mode

Bits s38 , s39 Transmission mode

00 2K mode
01 8K mode
10 4K mode
11 reserved

DVB-H signalling
Bits s48 and s49 shall be used to indicate to the receivers the transmission of DVB-H
services in compliance with table A.10.
In case of hierarchical transmission, the signification of these bits varies with the
parity of the OFDM frame transmitted, as follows:
- when received during OFDM frame number 1 and 3 of each super frame, DVB-
H signalling shall be interpreted as in relation with the High Priority stream
(HP);
- when received during OFDM frame number 2 and 4 of each super frame, DVB-
H signalling shall be interpreted as in relation with the Low Priority stream
(LP).

In case of non-hierarchical transmission, every frame in the super-frame carries the

same information.

Table A.10. DVB-H service indication

s48 s49 Transmission mode

0 x Time Slicing is not used
1 x At least one elementary stream uses Time Slicing
x 0 MPE-FEC not used
x 1 At least one elementary stream uses MPE-FEC
NOTE: “x” means whatever bit state.

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Bibliography

[1] ETSI EN 300 421: “Digital Video Broadcasting (DVB); Framing structure,
channel coding and modulation for 11/12 GHz satellite services (V1.1.2)”. Au-
gust 1997.
[2] ETSI EN 300 429: “Digital Video Broadcasting (DVB); Framing structure,
channel coding and modulation for cable systems (V1.2.1)”. April 1998.
[3] W. Fischer, Digital Television - A Pratical Guide for Engineers. Springer-Verlag,
2004.
[4] ETSI EN 300 744: “Digital Video Broadcasting (DVB); Framing structure,
channel coding and modulation for digital terrestrial television (V1.5.1)”.
November 2004.
[5] ISO/IEC 13818 (Parts 1 to 3): “Information technology - Generic coding of
moving pictures and associated audio information”. 1998.
[6] ETSI TR 101 190: “Digital Video Broadcasting (DVB); Implementation guide-
lines for DVB terrestrial services; Transmission aspects (V1.2.1)”. November
2004.

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List of Tables

List of Tables

1.1 Puncturing pattern and transmitted sequence after parallel-to-serial

conversion for the possible code rates . . . . . . . . . . . . . . . . . . 7
1.2 Bit-wise interleaver permutation function . . . . . . . . . . . . . . . . 10
1.3 Bit permutations for 2K mode . . . . . . . . . . . . . . . . . . . . . . 10
1.4 Bit permutations for 8K mode . . . . . . . . . . . . . . . . . . . . . . 11
1.5 Numerical values for the OFDM parameters for the 8K and 2K modes
for 8 MHz channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.6 Duration of symbol part for the allowed guard intervals for 8 MHz
channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7 Normalization factor for data symbols . . . . . . . . . . . . . . . . . . 16
1.8 Carrier indices for continual pilot carriers . . . . . . . . . . . . . . . . 18
1.9 Carrier indices for TPS carriers . . . . . . . . . . . . . . . . . . . . . 19
1.10 TPS signalling information and format . . . . . . . . . . . . . . . . . 19
1.11 Signalling format for frame number . . . . . . . . . . . . . . . . . . . 21
1.12 Signalling format for the possible constellation patterns . . . . . . . . 21
1.13 Signalling format for the α values . . . . . . . . . . . . . . . . . . . . 21
1.14 Signalling format for each of the code rates . . . . . . . . . . . . . . . 22
1.15 Signalling format for each of the guard interval values . . . . . . . . . 22
1.16 Signalling format for transmission mode . . . . . . . . . . . . . . . . 23
1.17 Mapping of the cell id on the TPS bits . . . . . . . . . . . . . . . . . 23
1.18 Net data rates in the DVB-T system (in Mbit/s) . . . . . . . . . . . . 25

A.1 Bit permutations for 4K mode . . . . . . . . . . . . . . . . . . . . . . 32

A.2 Numerical values for the OFDM parameters for the 4K mode for
8 MHz channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
A.3 Duration of symbol part for the allowed guard intervals for 8 MHz
channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
A.4 Carrier indices for continual pilot carriers . . . . . . . . . . . . . . . . 34
A.5 Carrier indices for TPS carriers . . . . . . . . . . . . . . . . . . . . . 34
A.6 TPS signalling information and format . . . . . . . . . . . . . . . . . 35
A.7 Signalling format for in-depth inner interleaver . . . . . . . . . . . . . 35

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List of Tables

A.8 Signalling format for Hierarchy information . . . . . . . . . . . . . . . 35

A.9 Signalling format for transmission mode . . . . . . . . . . . . . . . . 36
A.10 DVB-H service indication . . . . . . . . . . . . . . . . . . . . . . . . 36

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List of Figures

List of Figures

1.1 Functional block diagram of a DVB-T transmitter . . . . . . . . . . . 3

1.2 MPEG-2 transport multiplexer packet . . . . . . . . . . . . . . . . . 4
1.3 Scrambler/descrambler schematic diagram . . . . . . . . . . . . . . . 5
1.4 Randomized transport packets . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Reed-Solomon RS(204,188,t = 8) error protected packets . . . . . . . 6
1.6 Conceptual diagram of the outer interleaver and deinterleaver . . . . 6
1.7 The mother convolutional code of rate 1/2 . . . . . . . . . . . . . . . 7
1.8 Inner interleaver: a) non-hierarchical transmission mode, b) hierar-
chical transmission mode . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.9 Constellation examples: a) uniform 16-QAM or non-uniform 16-QAM
with α = 1, b) non-uniform 16-QAM with α = 2, c) non-uniform 16-
QAM with α = 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.10 Generation of PRBS sequence . . . . . . . . . . . . . . . . . . . . . . 16
1.11 Location of scattered pilot cells • = scattered pilot, ◦ = data . . . . . 17
1.12 Theoretical DVB transmission signal spectrum for guard interval ∆ =
TU /4 (for 8 MHz channels) . . . . . . . . . . . . . . . . . . . . . . . . 26
1.13 Time-domain DVB-T signal for guard interval ∆ = TU /4 and 64-
QAM modulation scheme . . . . . . . . . . . . . . . . . . . . . . . . . 27

A.1 Functional block diagram of the additional features . . . . . . . . . . 30

A.2 In-depth inner interleaver for 2K and 4K modes . . . . . . . . . . . . 31

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