ISO/IEC 4005-2:2023

Telecommunications and information exchange between systems — Unmanned aircraft area network (UAAN) — Part 2: Physical and data link protocols for shared communication

This document describes communication protocols for the physical and data link layer of shared communication, which is a wireless distributed communication network for units related with UAs in level II. Physical layer includes frame structure, encoding procedure, physical layer procedure and coexistence operations. Data link layer includes channel and slot, resource management, broadcast and exchange of data, synchronization, security, and interface with upper layer and other communication layers.

Télécommunications et échange d'information entre systèmes — Réseau de zone de drones (Unmanned aircraft area network - UAAN) — Partie 2: Protocoles de liaison de données et physiques pour la communication partagée

General Information

• Status: Published
• Publication Date: 21-Mar-2023
• ICS: 35.100.10 - Physical layer
• ICS: 35.100.20 - Data link layer
• ICS: 49.020 - Aircraft and space vehicles in general
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6/WG 1 - Physical and data link layers
• Current Stage: 6060 - International Standard published
• Start Date: 22-Mar-2023
• Due Date: 09-Feb-2023
• Completion Date: 22-Mar-2023

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 4005-2
First edition
2023-03
Telecommunications and information
exchange between systems —
Unmanned aircraft area network
(UAAN) —
Part 2:
Physical and data link protocols for
shared communication
Télécommunications et échange d'information entre systèmes —
Réseau de zone de drones (Unmanned aircraft area network -
UAAN) —
Partie 2: Protocoles de liaison de données et physiques pour la
communication partagée
Reference number
ISO/IEC 4005-2:2023(E)
© ISO/IEC 2023

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ISO/IEC 4005-2:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO/IEC 4005-2:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Physical layer . 3
5.1 Physical layer frame structure . . 3
5.1.1 Data channel . 3
5.1.2 Tone channel . 4
5.2 Encoding procedure . 7
5.2.1 CRC encoding . 8
5.2.2 Turbo encoding . 8
5.2.3 Rate matching . 11
5.2.4 Interleaving . 11
5.2.5 Modulation mapping . 11
5.2.6 Burst mapping . 11
5.2.7 Pulse mapping .13
5.3 Physical layer procedure . 14
5.3.1 Slot synchronization . 14
5.3.2 Transmit power control . 14
5.3.3 Measurements . 14
5.4 Coexistence operation. 14
6 Data link layer .15
6.1 General . 15
6.2 Channel and slot . 16
6.2.1 General . 16
6.2.2 Information tone slot . 16
6.3 Allocation and occupation and return of data slot . 16
6.3.1 General . 16
6.3.2 Mapping of data slots and competition tone slots . 16
6.3.3 Allocation and occupation and return of broadcast slot . 18
6.3.4 Talk slot allocation transmission and response transmission . 27
6.4 Data broadcast and exchange . 30
6.4.1 Data packet format . 30
6.4.2 Slot planning . 37
6.4.3 Data broadcasting . 39
6.4.4 Data exchange .40
6.4.5 Interworking with CC and VC. 41
6.5 Synchronization . 41
6.6 Data link layer security . 42
6.7 Interface with upper layer. 43
6.7.1 General . 43
6.7.2 Initialization interface. 43
6.7.3 Dynamic Interface .46
6.8 Interface with other communication layer .49
6.8.1 General .49
6.8.2 Interface with CC .49
6.8.3 Interface with VC . . 51
Annex A (normative) Turbo internal interleaver table .53
Annex B (normative) Parsing field description of PB 0x8D .55
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ISO/IEC 4005-2:2023(E)
Annex C (normative) Way point information.59
Annex D (informative) Subslot signal waveform example and spectrum .60
Annex E (informative) Competition example .62
Annex F (informative) Slot clearing example .64
Annex G (informative) Information tone slot example .65
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ISO/IEC 4005-2:2023(E)
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.
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ISO/IEC 4005-2:2023(E)
Introduction
Unmanned aircrafts (UAs) operating at low altitude 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 shared communication, which is a wireless distributed communication.
Shared communication allows all units related with UAs to communicate with UAs when necessary.
Shared communication can support communication between UAs, UAs and controllers, UAs and
ground equipment, UAs and landing devices, and UAs and obstacle devices. 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 (this document): It describes communication in which all units involved in UA
operations 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: 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.
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INTERNATIONAL STANDARD ISO/IEC 4005-2:2023(E)
Telecommunications and information exchange between
systems — Unmanned aircraft area network (UAAN) —
Part 2:
Physical and data link protocols for shared communication
1 Scope
This document describes communication protocols for the physical and data link layer of shared
communication, which is a wireless distributed communication network for units related with UAs in
level II.
Physical layer includes frame structure, encoding procedure, physical layer procedure and coexistence
operations. Data link layer includes channel and slot, resource management, broadcast and exchange of
data, synchronization, security, and interface with upper layer and other communication layers.
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 4005-3:2023, Telecommunications and information exchange between systems — Unmanned
aircraft area network (UAAN) — Part 3: Physical and data link protocols for control communication
ISO/IEC 4005-4:2023, Telecommunications and information exchange between systems — Unmanned
aircraft area network (UAAN) — Part 4: Physical and data link protocols for video 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 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/
3.1
broadcast slot
slot used to broadcast the information of a unit
3.2
data slot block
block in which multiple slots are grouped together for efficient resource allocation
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ISO/IEC 4005-2:2023(E)
3.3
linearization slot
slot used to maintain the linearity of the power amplifier
3.4
response clearing
transmission of a tone signal in subslot 0 of the subslot set corresponding to the same slot of this frame,
in order to respond to a talk packet received in a slot of the previous frame
3.5
slot block
block in which four slots are grouped together to perform efficient competition
3.6
super frame slot
slot with a frame period greater than one second
3.7
talk slot
slot used to exchange information with a specific counterpart
3.8
tone slot block
block in which multiple slots are grouped together to perform efficient competition
4 Abbreviated terms
CC Control Communication
CRC Cyclic Redundancy Check
CSCH Control Subchannel
DL Data Link
DLL Data Link Layer
DQPSK Differential Quadrature Phase Shift Keying
GF Galois Field
LFSR Linear Feedback Shift Register
PCCC Parallel Concatenated Convolutional Code
PB Parsing Block
PF Parsing Field
PN Pseudo Noise
SA Source Address
SC Shared Communication
SRRC Square Root Raised Cosine
TX Transmission
UTC Coordinated Universal Time
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ISO/IEC 4005-2:2023(E)
VC Video Communication
VSCH Video Subchannel
5 Physical layer
5.1 Physical layer frame structure
5.1.1 Data channel
5.1.1.1 Frame structure
The frame length of the data channel is 1 second and consists of 500 slots. The one slot time T is 2 ms.
s
A data slot block has four slots. Therefore, there are 125 slot blocks in one frame, and the slot block is
8 ms in length as shown in Figure 1. The frame number changes from 0 to 59 in 1 min interval.

a
1 frame, T =1 second=500 T .
f s
b
1 slot, T =2 ms.
s
c
1 slot block, T =8 ms=4 T .
sb s
Figure 1 — Data channel frame structure
5.1.1.2 Slot block transmit time mask
The transmission time mask of a slot block is shown Figure 2.
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ISO/IEC 4005-2:2023(E)
Key
T 0 μs
0
T , T , …, T symbol time offsets from T
1 2 17 0
a
8 ms.
b
Modulated signal.
Figure 2 — Transmission time mask of a slot block
T , T , T , T , T , T , T , T , T , T , T , T , T , T , T , T , T are symbol offsets from T , and symbol
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 0
time is 1/672000 second. Each value is as follows.
T is 152, T is 154, T is 1449, T is 1451, T is 1456.5, T is 1459.5, T is 2754.5, T is 2756.5, T is 2763,
1 2 3 4 5 6 7 8 9
T is 2765, T is 4060, T is 4062, T is 4068.0, T is 4070.5, T is 5365.5, T is 5366.5, T is 5376.
10 11 12 13 14 15 16 17
T is 0 μs as the start time of the slot block. T , T , T and T are offsets when the power amplifier is
0 1 5 9 13
gated on, and unmodulated fine signals begin to be transmitted. T , T , T , and T are offsets at which
2 6 10 14
modulation signal transmission starts. T , T , T , and T are offsets at which the transmission of the
3 7 11 15
modulated signal ends. T , T , T , and T are offsets at which the power amplifier is gated off, and
4 8 12 16
transmission of unmodulated fine signals is stopped. The transmit powers of T to T , T to T , T to
1 2 3 4 5
T , T to T , T to T , T to T , T toT and T to T shall be at least 50 dB less than the modulation
6 7 8 9 10 11 12 13 14 15 16
signal transmit power.
5.1.2 Tone channel
5.1.2.1 Frame structure
5.1.2.1.1 General
There are two types of tone channels. One is a competition tone channel and the other is an
information tone channel. The competition tone channel is used for resource allocation, occupation,
and management operations. Information tone channels are used to convey simple information. In this
document, the frame structure for the information tone channel is described, but whether and how to
use the information tone channel is determined by the upper layer.
5.1.2.1.2 Information tone channel frame structure
The frame length of information tone channel is 1 sec and the number of slots per frame is 500. One slot
is divided into 33 subslots, and the length T of a subslot is 60 μs as shown in Figure 3. The information
ss
given to each subslot is determined by the upper layer. SS means the x-th subslot (see Annex G).
x
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ISO/IEC 4005-2:2023(E)

a
1 frame, T = 1 second = 500 T .
f s
b
1 slot, T = 2 ms.
s
c
T = 60 μs.
ss
d
20 μs.
Figure 3 — Frame structure of information tone channel
5.1.2.1.3 Competition tone channel frame structure
The frame length of competition tone channel is 1 sec and the number of slots per frame is 500. Four
tone slots constitute one slock block. Thus, there are 125 slot blocks in one second frame. There are a
total of 132 subslots in one slot block. The length T of the subslot is 60 μs. The 132 subslots are divided
ss
into four parts, as shown in Figure 4, according to each slot numbers.
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ISO/IEC 4005-2:2023(E)

a
1 frame, T = 1 second = 500 T .
f s
b
1 slot, T = 2 ms.
s
c
1 slot block, T = 8 ms.
sb
d
T = 60 μs.
ss
e
40 μs.
Figure 4 — Frame structure of competition tone channel
The n-th slot block is composed of the following subslots.
— (0, 4n), (0, (4n + 1)), (0, (4n + 2)), (0, (4n + 3)), (1, 4n), (1, (4n + 1) ), (1, (4n + 2)), (1, (4n + 3)),. , (32,
4n), (32, (4n + 1)), (32, (4n + 2)), (32, (4n + 3))
where (x, y) is the x-th subslot of the y-th subslot set. The 132 subslots constitute 4 subslot sets.
5.1.2.2 Subslot transmit time mask
Subslot transmission time mask is shown in Figure 5.
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ISO/IEC 4005-2:2023(E)
Key
T , T , T , and T are time offsets from T
1 2 3 4 0
T is 1 μs
1
T is 41 μs
2
T is 42 μs
3
T is 60 μs
4
T is the start time of the subslot, the power amplifier is gated on and the unmodulated fine signal starts to be
0
transmitted
T is the time at which transmission of the modulated signal begins
1
T is the time at which transmission of the modulated signal is terminated
2
T is the time when the power amplifier is gated off and the transmission of unmodulated fine signals is stopped
3
a
Subslot start.
b
Subslot end.
c
Tone signal.
d
Guard time.
Figure 5 — Subslot transmission time mask
The transmission power between T and T and between T and T shall be 50 dB less or less than the
0 1 2 3
maximum transmission power of the modulated signal.
5.1.2.3 Subslot signal waveform
The modulation scheme of subslot signal is on-off keying. The subslot transmission signal is transmitted
in the 40 μs interval from T to T in Figure 5. The waveform of the subslot transmission signal uses a
1 2
raised cosine function. The subslot signal is generated by the following formula.
cos(()πα tT−2 )
()tT−2
 
gt(;α)= sinc , 04≤≤t TT (1)
 
2
T
 
12−−((α tT2 )/T)
where
α is 0,75 as a roll-off factor;
T is 10 μs as a raised cosine period.
See Annex D.
5.2 Encoding procedure
The encoding follows the following procedure as shown in Figure 6. CRC encoding, turbo coding, rate
matching, interleaving, modulation mapping, burst mapping, and pulse mapping are performed in this
order.
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ISO/IEC 4005-2:2023(E)
Figure 6 — Encoding procedure
The number of symbols according to each encoding stage is shown in Table 1.
Table 1 — Number of symbols at each encoding stage
Stage Number of symbols
a 792 (binary)
b 816 (binary)
c 2460 (binary)
d 2432 (binary)
e 2432 (binary)
f 1216 (Complex)
g 1288 (Complex)
h 1295×OS (Complex)
5.2.1 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 (2)
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 (3)
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 = (4)
k
Pf, orkA=+,,,AA12++,A 23
kA−
5.2.2 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
1/3. The structure of the turbo encoder is shown in Figure 7. The PCCC transfer function is as follows:
G(D) = [1, g (D)/g (D)] (5)
1 0
2 3 3
where g (D) = 1+D +D , g (D) = 1+D+D .
0 1
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ISO/IEC 4005-2:2023(E)
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, …, K-1, the output value of the turbo encoder is expressed as follows:
c = x
3k k
c = z
3k+1 k
c = z’ (6)
3k+2 k
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
3 B-1 0 1 2 3 B-1 0 1 2 3 B-1
code internal interleaver that is described in Annex A are represented by b’ , b’ , b’ , b’ , …, b’ and
0 1 2 3 B-1
these output bits are used as inputs for the second 8-state constituent encoder. The turbo code internal
interleaver shall use Table A.1 in Annex A.
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’
3B B 3B+3 B+1 3B+6 B 3B+9 B+1
c = z , c = x , c = z’ , c = x’
3B+1 B 3B+4 B+2 3B+7 B 3B+10 B+2
c = x , c = z , c = x’ , c = z’ (7)
3B+2 B+1 3B+5 B
...