ISO/IEC 4005-4:2023

INTERNATIONAL ISO/IEC
STANDARD 4005-4
First edition
2023-03
Telecommunications and information
exchange between systems —
Unmanned aircraft area network
(UAAN) —
Part 4:
Physical and data link protocols for
video communication
Télécommunications et échange d'information entre systèmes —
Réseau de zone de drones (Unmanned aircraft area network -
UAAN) —
Partie 4: Protocoles de liaison de données et physiques pour la
communication vidéo
Reference number
© ISO/IEC 2023
© ISO/IEC 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO/IEC 2023 – All rights reserved

Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 1
5 Physical layer . 2
5.1 Channel and frame structure for data channel . 2
5.1.1 The number of data channels and bandwidth . 2
5.1.2 Frame structure . 3
5.1.3 Slot transmit time mask . . 3
5.1.4 Sub channels . 4
5.1.5 Dedicated subchannels . 5
5.2 Channel and frame structure for tone channel . 5
5.2.1 General . 5
5.2.2 Slot transmit power . 5
5.3 Encoding procedure . 5
5.3.1 CRC encoding . 6
5.3.2 Turbo encoding . 6
5.3.3 Rate matching . 9
5.3.4 Interleaving . 9
5.3.5 Modulation mapping . 9
5.3.6 Burst mapping . 9
5.3.7 Pulse mapping . 11
5.4 Physical layer procedure .12
5.4.1 Synchronization .12
5.4.2 Subchannel power .12
5.4.3 Measurements .12
5.4.4 Coexistence operation .12
6 Data link layer .13
6.1 General .13
6.2 Channel mapping and measurements. 14
6.2.1 General . 14
6.2.2 Mapping of communication resources and subslot sets. 14
6.2.3 Interference power calculation . 15
6.2.4 Subchannel map . 16
6.3 Subchannel negotiation for allocation . 16
6.3.1 General . 16
6.3.2 Subchannel negotiation using shared channel . 20
6.3.3 Subchannel negotiation using dedicated slot . 23
6.3.4 Subchannel negotiation using CSCH . 24
6.4 Subchannel allocation and generated link confirmation . 25
6.4.1 General . 25
6.4.2 Subchannel resource allocation competition . 26
6.4.3 Generated link confirmation . 27
6.4.4 Broadcasting video subchannel (VSCH) information being allocated or
occupied .28
6.5 Subchannel occupation and collision management .29
6.5.1 General .29
6.5.2 Power control in occupation stage .29
6.5.3 Subchannel occupation and return method.30
6.5.4 Collision tone transmission and collision management .30
iii
© ISO/IEC 2023 – All rights reserved

6.5.5 Parsing block for video channel .30
6.6 Reallocation . . 30
6.6.1 General .30
6.6.2 Reallocation decision . 31
6.6.3 Subchannel reallocation procedure . 32
6.7 Data exchange . 33
6.7.1 General . 33
6.7.2 Data packet format .34
6.8 Synchronization . 35
6.9 Data link layer security . 35
6.10 Interface with upper layer. 37
6.10.1 General . 37
6.10.2 Initialization interface. 37
6.10.3 Dynamic interface . 42
6.11 Interface with other communication layer .46
6.11.1 General .46
6.11.2 Interface with SC .46
6.11.3 Interface with CC . 47
Annex A (normative) Turbo internal interleaver table .50
iv
© ISO/IEC 2023 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC
list of patent declarations received (see https://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 6, Telecommunications and information exchange between systems.
A list of all parts in the ISO/IEC 4005 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
v
© ISO/IEC 2023 – All rights reserved

Introduction
Unmanned aircrafts (UAs) operating at low altitudes will provide a variety of commercial services in
the near future. UAs that provide these services are distributed in the airspace. In level II, many people
operate their own UAs without the assignment of communication channels from a central control
centre.
This document describes video communication, which is a wireless distributed communication. Video
communication allows UAs distributed over the airspace to transmit video without serious interference
to the relevant video receiver which is usually a controller. The channels used for video communication
have a multi-channel structure, which enables UA and video receiver pairs to independently use the
occupied communication link. A wireless distributed communication described by this document is
intended to be used in licensed frequency bands.
The ISO/IEC 4005 series consists of the following four parts:
ISO/IEC 4005-1: To support various services for UAs, it describes a wireless distributed communication
model and the requirements that this model shall satisfy.
ISO/IEC 4005-2: It describes communication in which all units involved in UA operation can broadcast
or exchange information by sharing communication resources with each other.
ISO/IEC 4005-3: It describes the control communication for the controller to control the UA.
ISO/IEC 4005-4 (this document): It describes video communication for UAs to send video to a controller.

The International Organization for Standardization (ISO) and International Electrotechnical
Commission (IEC) draw attention to the fact that it is claimed that compliance with this document may
involve the use of patents.
ISO and IEC take no position concerning the evidence, validity and scope of these patent rights.
The holders of these patent rights have assured ISO and IEC that they are willing to negotiate licences
under reasonable and non-discriminatory terms and conditions with applicants throughout the world.
In this respect, the statements of the holders of these patent rights are registered with ISO and IEC.
Information may be obtained from the patent database available at www.iso.org/patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights other than those in the patent database. ISO and IEC shall not be held responsible for
identifying any or all such patent rights.
vi
© ISO/IEC 2023 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 4005-4:2023(E)
Telecommunications and information exchange between
systems — Unmanned aircraft area network (UAAN) —
Part 4:
Physical and data link protocols for video communication
1 Scope
This document specifies communication protocols for the physical and data link layer of video
communication, which is a wireless distributed communication network for units related with
unmanned aircrafts (UAs) in level II.
This document describes video communication, which is one-to-one communication that transmits
video from a UA to a video receiver. For the specific use of video communication, video can be
transmitted from a UA to multiple receivers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 4005-1, Telecommunications and information exchange between systems — Unmanned aircraft
area network (UAAN) — Part 1: Communication model and requirements
ISO/IEC 4005-2, Telecommunications and information exchange between systems — Unmanned aircraft
area network (UAAN) — Part 2: Physical and data link protocols for shared communication
ISO/IEC 4005-3, Telecommunications and information exchange between systems — Unmanned aircraft
area network (UAAN) — Part 3: Physical and data link protocols for control communication
ISO 21384-4, Unmanned aircraft systems — Part 4: Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in ISO/IEC 4005-1, ISO/IEC 4005-2,
ISO/IEC 4005-3, ISO 21384-4 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Abbreviated terms
CC Control Communication
CB Coding Block
CRC Cyclic Redundancy Check
© ISO/IEC 2023 – All rights reserved

CSCH Control Subchannel
DL Data Link
DLL Data Link Layer
DQPSK Differential Quadrature Phase Shift Keying
DS Dedicated Slot
FN Frame Number
GF Galois Field
PCCC Parallel Concatenated Convolutional Code
PB Parsing Block
PH Parsing Header
PKH Packet Header
PN Pseudo Noise
SA Source Address
SC Shared Communication
SRRC Square Root Raised Cosine
TSB Tone Slot Block
UTC Coordinated Universal Time
VC Video Communication
VSCH Video Subchannel
5 Physical layer
5.1 Channel and frame structure for data channel
5.1.1 The number of data channels and bandwidth
The number of data channels is L. L is greater than or equal to one. The bandwidth of one data channel
is 5 MHz as shown in Figure 1. The L is determined in the upper layer.
Figure 1 — Data channels in frequency region
© ISO/IEC 2023 – All rights reserved

5.1.2 Frame structure
The frame length of the data channel is 1 sec and consists of 250 slots. The one slot time T is 4 ms. A
s
data slot block has 2 slots. Therefore, there are 125 data slot blocks in one frame, and the data slot block
is 8 ms in length as shown in Figure 2. The frame number, FN changes from 0 to 59 in a 1 min interval,
and has the same value as the second of the current time.
a
1 frame, T = 1 second = 250 T .
f s
b
1 slot, T = 4 ms.
s
c
1 slot block, T = 8 ms = 2 T .
sb s
Figure 2 — Data channel frame structure
5.1.3 Slot transmit time mask
The transmission time mask of a slot is as shown in Figure 3.
Key
T 0 μs
T , T , T , T symbol offset from T
1 2 3 4 0
a
4 ms.
b
Modulated signal.
Figure 3 — The transmission time mask of a slot
T , T , T , T are symbol offsets from T and symbol time is 1/2688000 sec. Each value is as follows: T is
1 2 3 4 0 1
8, T is 10380, T is 10388, T is 10752.
2 3 4
T is 0 μs as the start time of the slot and the power amplifier is gated on and unmodulated fine signals
begin to be transmitted. T is an offset at which modulation signal transmission starts. T is an offset
1 2
at which the transmission of the modulated signal ends. T is an offset at which the power amplifier is
gated off, and transmission of unmodulated fine signals is stopped. The transmit power of T to T , T to
0 1 2
T shall be at least 50 dB less than the modulation signal transmit power.
© ISO/IEC 2023 – All rights reserved

5.1.4 Sub channels
a
V
x
b
V
x,0
c
V
x,1
d
V
x,8
e
V
x,9
Figure 4 — Sub channel structure of video communication in even frame
One data channel consists of 10 subchannels as shown in Figure 4. Subchannel y of video channel x is
composed of the following slot set.
V = S , S , S , …, S
x,y x,z x,z+10 x,z+20 x,z+240
ye, venframe
z= (1)
yy+−12(mod )/22× , oddframe
 
 
where
y is subchannel number, y=0, 1, …, 9;
S is slot z of video channel x.
x,z
© ISO/IEC 2023 – All rights reserved

The subchannel consists of 25 slots, the i-th slot resource of the subchannel y of the channel x is indicated
by SR , and the subchannel y of frequency channel x is indicated by V . Therefore, V is as follows:
x,y,i x,y x,y
V = SR , SR , …, SR (2)
x,y x,y,0 x,y,1 x,y,24
where SR  is i-th slot resource of subchannel y of channel x, i=0, …, 24.
x,y,i
All slots of video channel are downlink.
5.1.5 Dedicated subchannels
The upper layer can predetermine one or several subchannels as dedicated subchannels. In this case,
the tone subslot set mapped with the dedicated subchannel is not used as a competition tone and can be
used for other purposes.
Dedicated subchannel information is received from an upper layer through UPtoDL.
InfoDedicatedChannel.
5.2 Channel and frame structure for tone channel
5.2.1 General
The tone channel of video communication means a competitive tone channel. The tone channel used
for video communication resource allocation and the tone channel used for control communication
resource allocation are the same channel (see ISO/IEC 4005-3).
5.2.2 Slot transmit power
The maximum transmission power PmaxTCH of the tone slot mapped to the video subchannel (VSCH)
is received as UPtoDL.InfoPowerParamVCH from the upper layer. The power of the tone subslot signal
is determined by adding the PTX_VCHTCH_differ value to the transmission power of the mapped VSCH.
5.3 Encoding procedure
The encoding follows the following procedure. CRC encoding, turbo coding, rate matching, interleaving,
modulation mapping, burst mapping, and pulse mapping are performed in this order as shown in
Figure 5.
Figure 5 — Encoding procedure
The number of symbols according to each encoding stage is shown in Table 1, where the encoding
input consists of two code blocks, CB0 and CB1 as shown in Figure 14. Each code block undergoes CRC
encoding, turbo coding, rate matching, interleaving, and modulation mapping processes, respectively.
The length of each code block in these processes is 4094, 4928, 9868, 9856, 9856, and 4928. The two
code blocks are merged into one burst during burst mapping.
© ISO/IEC 2023 – All rights reserved

Table 1 — Number of symbols at each encoding stage
Stage Number of symbols
a 4904 × 2 (binary)
b 4928 × 2 (binary)
c 9868 × 2 (binary)
d 9856 × 2 (binary)
e 9856 × 2 (binary)
f 4928 × 2 (complex)
g 10364 (complex)
h 10372 × OS (complex)
5.3.1 CRC encoding
The input bits are defined as a , a , a , a , …, a and parity bits as p , p , p , p , …, p where A represents
0 1 2 3 A-1 0 1 2 3 23
the number of input sequences. Parity bits are generated through CRC generation polynomial as follows.
24 22 6 5
g (D) = D + D + D + D + D + 1 (3)
CRC
The encoding performed through the cyclic generator polynomials has a systematic form as follows.
The resulting polynomial has zero remainder when it is divided by g (D) on GF(2).
CRC
A+23 A+22 24 23 22 1
a D + a D + … + a D + p D + p D + … + p D + p (4)
0 1 A-1 0 1 22 23
After CRC insertion, bits are represented by b , b , b , b , …, b (where B = A + 24), and the relationship
0 1 2 3 B-1
between a and b is as follows.
k k
af, orkA=−01,,,21,
k
b = (5)
k
Pf, orkA=+,,,AA12++,A 23
kA−
5.3.2 Turbo encoding
The turbo encoder consists of Parallel Concatenated Convolutional Code (PCCC) with two 8-state
constituent encoders and one turbo coded internal interleaver. The coding rate of the turbo encoder is
1/2. The structure of the turbo encoder is shown in Figure 6. The PCCC transfer function is as follows.
G(D) = [1, g (D)/g (D)] (6)
1 0
2 3 3
where g (D) = 1+D +D , g (D) = 1+D+D .
0 1
When the input bits of the turbo encoder are encoded, the initial values of the shift registers of the
8-state constituent encoder shall all be zero.
For k = 0, 1, 2, …, B/2-1, the output value of the turbo encoder is expressed as follows.
c = x
4k 2k
c = z
4k+1 2k
c = x
4k+2 2k+1
© ISO/IEC 2023 – All rights reserved

c = z’ (7)
4k+3 2k+1
Output bits of the first and second 8-state constituent encoders for turbo encoder input bits b , b , b ,
0 1 2
b , …, b are z , z , z , z , …, z and z’ , z’ , z’ , z’ , …, z’ , and the output bits through the turbo code
3 B-1 0 1 2 3 B-1 0 1 2 3 B-1
internal interleaver that is described in Annex A are represented by b’ , b’ , b’ , b’ , …, b’ . These output
0 1 2 3 B-1
bits are used as inputs for the second 8-state constituent encoder.
Trellis termination is performed by taking tail bits from shift register feedback after all information
bits have been encoded. The generated tail bits are added after encoding of the information bits.
The first three tail bits are used for the first constituent encoder termination and not the second
constituent encoder. The remaining three tail bits are used for the termination of the second constituent
encoder and not the first constituent encoder.
The bits transmitted for trellis termination are determined as follows.
c = x , c = z , c = x’ , c = z’
2B B 2B+3 B+1 2B+6 B 2B+9 B+1
c = z , c = x , c = z’ , c = x’
2B+1 B 2B+4 B+2 2B+7 B 2B+10 B+2
c = x , c = z , c = x’ , c = z’ (8)
2B+2 B+1 2B+5 B+2 2B+8 B+1 2B+11 B+2
© ISO/IEC 2023 – All rights reserved

Key
1 turbo code internal interleaver
2 first constituent encoder
3 second constituent encoder
D register
b a k-th bit of turbo encoder input
k
b’ a k-th bit of turbo code internal interleaver output
k
x a k-th systematic bit of turbo encoder output
k
z a k-th bit of first constituent encoder output
k
x’ a k-th bit of second constituent encoder output for trellis termination
k
z’ a k-th bit of second constituent encoder output
k
Figure 6 — Turbo encoder structure
Input bit sequence of turbo code internal interleave, b , b , b , b , …, b and output bit sequence
0 1 2 3 B-1
generated from turbo code internal interleaver, b’ , b’ , b’ , b’ , …, b’ have the following relationship.
0 1 2 3 B-1
b’ = b (9)
i j
where the mapping between the output bit index i and the input bit index j shall follow Table A.1 of
Annex A where j and i are as follows, and row and column numbers start at zero.
j = (number shown in table) − 1
i = (row number in table) × 16+(column number in table) (10)
© ISO/IEC 2023 – All rights reserved

5.3.3 Rate matching
Rate matching outputs d , d , d , d , …, d by puncturing the input bits c , c , c , c , …, c . The
0 1 2 3 D-1 0 1 2 3 C-1
puncturing bit numbers are as follows.
— 821, 1643, 2461, 3283, 4101, 4923, 5741, 6563, 7381, 8203, 9021, 9843
5.3.4 Interleaving
The interleaver uses block interleaving with 77 rows and 128 columns.
e = d
m n
m = (n x 77) %9856 + ⎿n/128⏌ (11)
where ⎿x⏌ means the largest integer among integers less than or equal to x and 0 ≤ n ≤ 9855.
5.3.5 Modulation mapping
Modulation mapping generates a complex symbol f from the input bit e , 0 ≤ n ≤ 9855, 0 ≤ m ≤ 4927.
n m
Two input bits are mapped to one complex number as shown in Table 2.
Table 2 — Modulation mapping
e e 00 01 10 11
2n 2n+1
f exp( j/4π) exp( j·7/4π) exp( j·3/4π) exp( j·5/4π)
n
5.3.6 Burst mapping
Output complex symbols g , g , …, g are generated from f , f , …, f of CB0 and f , f , …, f of CB1.
0 1 4927 0 1 4927 0 1 4927
n
gc= ()k (12)
n
∏
k=0
where c(n) is shown in Table 3.
Table 3 — c(n)
Number of sym-
n c(n)
bols
0, 1 TSS(n) 2
2, …, 37 PTS1(n-2) 36
38, …, 767 f of CB0 730
n-38
768, …, 803 PTS1(n-768) 36
804, …, 1533 f of CB0 730
n-74
1534, …, 1569 PTS1(n-1534) 36
1570, …, 2299 f of CB0 730
n-110
2300, …, 2335 PTS1(n-2300) 36
2336, …, 3065 f of CB0 730
n-146
3066, …, 3101 PTS1(n-3066) 36
3102, …, 3831 f of CB0 730
n-182
3832, …, 3867 PTS1(n-3832) 36
3868, …, 4597 f of CB0 730
n-218
4598, …, 4633 PTS1(n-4598) 36
© ISO/IEC 2023 – All rights reserved

TTabablele 3 3 ((ccoonnttiinnueuedd))
Number of sym-
n c(n)
bols
4634, …, 5181 f of CB0 548
n-254
5182, … 5363 f of CB1 182
n-5182
5364, …,5399 PTS1(n-5364) 36
5400, …, 6129 f of CB1 730
n-5218
6130, …, 6165 PTS1(n-6130) 36
6166, …, 6895 f of CB1 730
n-5254
6896, …, 6931 PTS1(n-6896) 36
6932, …, 7661 f of CB1 730
n-5290
7662, …, 7697 PTS1(n-7662) 36
7698, …, 8427 f of CB1 730
n-5326
8428, …, 8463 PTS1(n-8428) 36
8464, …, 9193 f of CB1 730
n-5362
9194, …, 9229 PTS1(n-9194) 36
9230, …, 9959 f of CB1 730
n-5398
9960, …, 9995 PTS1(n-9960) 36
9996, …, 10361 f of CB1 366
n-5434
10362, 10363 TSS(n-10362) 2
where TSS(n) and PTS1(n) are shown in Table 4 and Table 5 respectively.
Table 4 — TSS(n)
TSS(0) TSS(1)
exp( j·3/4π) exp( j·7/4π)
Table 5 — PTS1(n)
n PTS1(n) n PTS1(n) n PTS1(n)
0 exp( j·5/4π) 12 exp( j·5/4π) 24 exp( j·7/4π)
1 exp( j·7/4π) 13 exp( j/4π) 25 exp( j·5/4π)
2 exp( j·7/4π) 14 exp( j/4π) 26 exp( j·7/4π)
3 exp( j·5/4π) 15 exp( j·5/4π) 27 exp( j/4π)
4 exp( j/4π) 16 exp( j·7/4π) 28 exp( j·5/4π)
5 exp( j/4π) 17 exp( j/4π) 29 exp( j·3/4π)
6 exp( j·3/4π) 18 exp( j·5/4π) 30 exp( j·3/4π)
7 exp( j·5/4π) 19 exp( j·3/4π) 31 exp( j/4π)
8 exp( j·3/4π) 20 exp( j·7/4π) 32 exp( j/4π)
9 exp( j/4π) 21 exp( j/4π) 33 exp( j·5/4π)
10 exp( j·5/4π) 22 exp( j/4π) 34 exp( j·3/4π)
11 exp( j·5/4π) 23 exp( j·3/4π) 35 exp( j·7/4π)
© ISO/IEC 2023 – All rights reserved

5.3.7 Pulse mapping
The complex symbol g is converted into a complex signal h , where the oversampling ratio of the filter
m n
is OS times and depends on implementation. For 0 ≤ n < 10372 × OS, the complex signal is defined as
follows.
nT
  10363 n
 
s
hw= p ()−−mT4 g (13)
 
n  ∑ sm
m=0
OS OS
 
 
where symbol duration T is the 1/2688000 second and pulse shape p(t) is defined as SRRC function of
s
roll-off factor 0,35 as follows.
sin(1−απ)/tT
 ()1+απt  ()
s
cos +
 
T 4αtT/
 
s ss
pt()= · (14)
()1−απ
14−(/αtT )
1+ s
4α
The window function w(t) is defined as follows.
(/12)(12−≤cos(πtT )), 02tT<
ss
12, Tt≤< 10370T
ss
wt()= (15)
 ππ 
(/12)(1− cos ()tT−10372 ), 10370Tt≤< 10372T
 ss s
2T
 
s
0,   otherwise
The modulated signal is shown in Figure 7. Timing of modulated signal transmission is as described in
5.1.3, i.e. the modulated signals are transmitted in the time intervals of T to T as shown in Figure 3.
1 2
Key
1 filter ripple (4 symbols)
2 TSS (2 symbols)
3 PTS1 (36 symbols)
4 data (730 symbols)
5 PTS1 (36 symbols)
6 data (730 symbols)
7 PTS1 (36 symbols)
8 data (730 symbols)
9 PTS1 (36 symbols)
10 data (336 symbols)
11 TSS (2 symbols)
12 filter ripple (4 symbols)
a
Modulated signal (10372 DQPSK symbol).
Figure 7 — Modulated signal structure
© ISO/IEC 2023 – All rights reserved

5.4 Physical layer procedure
5.4.1 Synchronization
All messages shall be transmitted based on UTC time. All times are measured based on UTC.
The synchronization mode of the unit includes 'A sync', 'B sync' and 'C sync'.
— A sync is synchronization obtained from UTC.
— B sync is secondary synchronization acquired from the synchronization signal of the A sync unit.
— C sync is sync status within 20 seconds after sudden loss of sync in A or B sync mode.
A sync unit shall know the date, hour, minute, second, slot number.
The time error of A sync shall be within ±0,4 μs. The time error of B sync shall be within ±4 μs. The time
error of C sync shall be within ±5 μs.
The frequency error of A sync shall be within ±0,1 ppm. The frequency error of the B sync shall be
within ±0,2 ppm. The frequency error of the C sync shall be within ±0,3 ppm.
5.4.2 Subchannel power
The maximum power PmaxVCH of the VSCH is received as UPtoDL.InfoPowerParamVCH from an upper
layer. The maximum transmission power and minimum transmission power of each VSCH are received
as UPtoDL.InfoPowerParamVCHsub from the upper layer. The power control of each VSCH is described
in the resource allocation procedure.
5.4.3 Measurements
The physical layer shall have the ability to measure the following parameters. The received signal
power of a tone subslot, the received signal power of a data slot, and propagation delay time of the
received data signal shall be measured. The receiving power determination point shall be the receiving
antenna connector.
5.4.4 Coexistence operation
If the hardware of shared communication described in ISO/IEC 4005-2 and the hardware of control
communication described in ISO/IEC 4005-3 and the hardware of video communication described
in this document are completely physically isolated and do not affect each other at all, it is possible
that coexistence operation is not performed, which is implementation dependent. In general, the
three communications affect each other, and in this case, the following coexistence operation shall be
performed.
The TX operation of a shared slot includes the TX of the corresponding shared slot and the TX operation
in the mapped tone subslot set. The TX operation of a control communication includes TX of the mapped
tone subslot set and TX in the subchannel for transmitting control data. The TX operation of video
communication includes TX of a mapped tone subslot set and TX in a subchannel for transmitting video
data.
When a UA periodically broadcasts its information to a shared slot of a shared channel, a shared slot
and a set of tone subslots mapped to the shared slot generally require 1 slot and 4 slots, respectively, for
TX operation. If the TX operation of the shared slot used for mandatory periodic broadcasting and the
TX operation of the video channel overlap, the TX operation of the shared slot shall be performed.
A control subchannel (CSCH) and a VSCH shall be allocated so that they do not overlap in time.
The TX time of the tone subslot set mapped with mandatory periodically broadcasted shared slot, the
TX time of the tone subslot set mapped with the CSCH, and the TX time of the tone subslot set mapped
© ISO/IEC 2023 – All rights reserved

with the VSCH shall not overlap each other. If the video tone slot block type is TSBtype0, the video tone
subslot set and the shared tone subslot set can be located in the same TSB. In this case, the two tone
subslot set numbers shall be different. If the video TSB type is not TSBtype0, the video tone subslot set
and the shared tone subslot set cannot be located in the same TSB.
The TX operation time of the tone subslot set mapped with a CSCH may overlap the TX time of a VSCH,
and in this case, the corresponding video slot cannot be transmitted. The TX operation time of the tone
subslot set mapped with a VSCH may overlap with the slot TX time of a CSCH, and in this case, the
corresponding control slot cannot be transmitted.
6 Data link layer
6.1 General
The data link layer allocates subchannels consisting of 25 slots to controllers and UAs. The controller
can use this subchannel to receive video from the UA. In this case, the controller shall include a video
channel receiver. The representative application service of video communication is that the controller
receives video from the UA, but it is possible to provide other services through the formed video link.
This is determined at the upper layer.
The process of using the VSCH is almost the same as the process of using the CSCH and shown in
Figure 8.
— negotiation of subchannel number to be allocated;
— competition for allocation and generated link confirmation;
— occupation and management of subchannels;
— subchannel return or reallocation.
Firstly, the UA and the controller each generate a map of the available subchannels. The controller
selects one of the subchannels available together and the controller transfers the selected subchannel
number to the UA where the subchannel negotiation is performed by the SC DLL or the CC DLL.
After that, the UA and the controller attempt to allocate subchannel at the same time. Subchannel can
be allocated only when the UA and the controller succeed in allocation at the same time. The controller
shall confirm whether a link is generated.
If the subchannel allocation is successful, the UA and the controller simultaneously perform slot clearing
to occupy the subchannel. While occupying a subchannel, the UA and the controller constantly check for
collisions of subchannel resources. They also calculate the amount of interference from neighboring
channels.
If collision of subchannel resources or interference with neighboring channels exceeding the threshold
is detected, the UA and the controller reallocate the subchannel. To do this, the UA and the controller
decide which subchannels to reallocate and perform allocation competition on that subchannel.
The UA and the controller return the subchannel when they can no longer maintain or need to maintain
them.
© ISO/IEC 2023 – All rights reserved

Figure 8 — Subchannel use procedure
6.2 Channel mapping and measurements
6.2.1 General
Allocating subchannel resources is performed by tone channel. One subslot set in a tone channel and
one subchannel have a mapping relationship. When one tone subslot set is allocated, a subchannel
mapped thereto is allocated.
In order for the UA and the controller to allocate a subchannel, the UA and the controller shall find
subchannels that can be allocated at the same time. To this end, the UA and the controller determine the
allocable subchannels by calculating the interference power for each subchannel.
6.2.2 Mapping of communication resources and subslot sets
The competition for allocating a subchannel is performed in the subslot set mapped thereto. Subslot
sets are mapped to subchannels.
© ISO/IEC 2023 – All rights reserved

The tone subslot set {S } is mapped to the subchannel V , where m is (((x mod 2)+ 2y+8) mod 20)
480+m-n x,y
- 20 × ⎿x/2⏌and n is as follows.
0, evenframe
n= (16)
20−(/xo22mod)×40, ddframe
 
 
Thereafter, {S } mapped to V is expressed as {S }.
480+m-n x,y x,y
This mapping shape is shown in Figure 9 key.
a) even frame
b) odd frame
a
Tone subslot set.
b
V , V , …, V , V , V .
0,6 1,6 1,4 0,5 1,5
c
V , V , …, V , V , V .
2,6 3,6 3,4 2,5 3,5
Figure 9 — Mapping of video subchannel (VSCH) and tone subslot sets
6.2.3 Interference power calculation
In order to allocate the VSCH, the controller shall calculate the interference power in the allocable
subchannel. Interference constants for calculating the interference power are received as UPtoDL.
InfoICConstant in the upper layer. The unit is dB. The estimated interference power of the subchannel is
expressed as PImVCH .
x,y
The interference power of the subchannel V experienced by the controller is calculated as follows.
x,y
N−1
PcIm VCHP=−()mdVCHIC (17)
xy,,iy xi−
∑
ii=≠0, x
where PmdVCH is the reception power of the tone transmitted by the UA in the tone subslot set
i,y
mapped with V and the unit of this is dBm. The unit of (PmdVCH − IC ) is also dBm.
i,y i,y |x-i|
© ISO/IEC 2023 – All rights reserved

6.2.4 Subchannel map
Each unit shall make a subchannel map indicating the availability of subchannels. The subchannel map
is expressed by 2 bits per subchannel.
In the case of a controller, a subchannel map shall be made as follows in consideration of the subchannel
interference.
If the subchannel interference PImVCH is PTH_SMI0 or less, it is written as '11'. If it is greater than
x,y
PTH_SMI0 and less than PTH_SMI1, it is written as '10', if it is greater than PTH_SMI1 and less than
PTH_SMI2, it is written as '01', and if it is greater than PTH_SMI2, it is written as '00', where, PTH_
SMI0, PTH_SMI1
...