Proximity-1 Space Link Protocol

Recommendation for Space Data System Standards

BLUE BOOK

PROXIMITY-1 SPACE

LINK PROTOCOL—

PHYSICAL LAYER

RECOMMENDED STANDARD

CCSDS 211.1-B-4

December 2013

Recommendation for Space Data System Standards

PROXIMITY-1 SPACE

LINK PROTOCOL—

PHYSICAL LAYER

RECOMMENDED STANDARD

CCSDS 211.1-B-4

BLUE BOOK

December 2013

CCSDS RECOMMENDED STANDARD FOR PROXIMITY-1 SPACE LINK PROTOCOL—

PHYSICAL LAYER

CCSDS 211.1-B-4 Page 1-1 December 2013

AUTHORITY

Issue: Recommended Standard, Issue 4

Date: December 2013

Location: Washington, DC, USA

This document has been approved for publication by the Management Council of the

Consultative Committee for Space Data Systems (CCSDS) and represents the consensus

technical agreement of the participating CCSDS Member Agencies. The procedure for

review and authorization of CCSDS documents is detailed in Organization and Processes for

the Consultative Committee for Space Data Systems (CCSDS A02.1-Y-3), and the record of

Agency participation in the authorization of this document can be obtained from the CCSDS

Secretariat at the address below.

This document is published and maintained by:

CCSDS Secretariat

Space Communications and Navigation Office, 7L70

Space Operations Mission Directorate

NASA Headquarters

Washington, DC 20546-0001, USA

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CCSDS 211.1-B-4 Page 1-2 December 2013

STATEMENT OF INTENT

The Consultative Committee for Space Data Systems (CCSDS) is an organization officially

established by the management of its members. The Committee meets periodically to address

data systems problems that are common to all participants, and to formulate sound technical

solutions to these problems. Inasmuch as participation in the CCSDS is completely

voluntary, the results of Committee actions are termed Recommended Standards and are

not considered binding on any Agency.

This Recommended Standard is issued by, and represents the consensus of, the CCSDS

members. Endorsement of this Recommendation is entirely voluntary. Endorsement,

however, indicates the following understandings:

o Whenever a member establishes a CCSDS-related standard, this standard will be in

accord with the relevant Recommended Standard. Establishing such a standard

does not preclude other provisions which a member may develop.

o Whenever a member establishes a CCSDS-related standard, that member will

provide other CCSDS members with the following information:

-- The standard itself.

-- The anticipated date of initial operational capability.

-- The anticipated duration of operational service.

o Specific service arrangements shall be made via memoranda of agreement. Neither

this Recommended Standard nor any ensuing standard is a substitute for a

memorandum of agreement.

No later than three years from its date of issuance, this Recommended Standard will be

reviewed by the CCSDS to determine whether it should: (1) remain in effect without change;

(2) be changed to reflect the impact of new technologies, new requirements, or new

directions; or (3) be retired or canceled.

In those instances when a new version of a Recommended Standard is issued, existing

CCSDS-related member standards and implementations are not negated or deemed to be

non-CCSDS compatible. It is the responsibility of each member to determine when such

standards or implementations are to be modified. Each member is, however, strongly

encouraged to direct planning for its new standards and implementations towards the later

version of the Recommended Standard.

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CCSDS 211.1-B-4 Page 1-3 December 2013

FOREWORD

Attention is drawn to the possibility that some of the elements of this document may be the

subject of patent rights. CCSDS shall not be held responsible for identifying any or all such

patent rights.

Through the process of normal evolution, it is expected that expansion, deletion, or

modification of this document may occur. This Recommended Standard is therefore subject

to CCSDS document management and change control procedures, which are defined in

Organization and Processes for the Consultative Committee for Space Data Systems

(CCSDS A02.1-Y-3). Current versions of CCSDS documents are maintained at the CCSDS

Web site:

http://www.ccsds.org/

Questions relating to the contents or status of this document should be addressed to the

CCSDS Secretariat at the address indicated on page i.

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At time of publication, the active Member and Observer Agencies of the CCSDS were:

Member Agencies

– Agenzia Spaziale Italiana (ASI)/Italy.

– Canadian Space Agency (CSA)/Canada.

– Centre National d’Etudes Spatiales (CNES)/France.

– China National Space Administration (CNSA)/People’s Republic of China.

– Deutsches Zentrum für Luft- und Raumfahrt (DLR)/Germany.

– European Space Agency (ESA)/Europe.

– Federal Space Agency (FSA)/Russian Federation.

– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.

– Japan Aerospace Exploration Agency (JAXA)/Japan.

– National Aeronautics and Space Administration (NASA)/USA.

– UK Space Agency/United Kingdom.

Observer Agencies

– Austrian Space Agency (ASA)/Austria.

– Belgian Federal Science Policy Office (BFSPO)/Belgium.

– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.

– China Satellite Launch and Tracking Control General, Beijing Institute of Tracking

and Telecommunications Technology (CLTC/BITTT)/China.

– Chinese Academy of Sciences (CAS)/China.

– Chinese Academy of Space Technology (CAST)/China.

– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.

– Danish National Space Center (DNSC)/Denmark.

– Departamento de Ciência e Tecnologia Aeroespacial (DCTA)/Brazil.

– European Organization for the Exploitation of Meteorological Satellites

(EUMETSAT)/Europe.

– European Telecommunications Satellite Organization (EUTELSAT)/Europe.

– Geo-Informatics and Space Technology Development Agency (GISTDA)/Thailand.

– Hellenic National Space Committee (HNSC)/Greece.

– Indian Space Research Organization (ISRO)/India.

– Institute of Space Research (IKI)/Russian Federation.

– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.

– Korea Aerospace Research Institute (KARI)/Korea.

– Ministry of Communications (MOC)/Israel.

– National Institute of Information and Communications Technology (NICT)/Japan.

– National Oceanic and Atmospheric Administration (NOAA)/USA.

– National Space Agency of the Republic of Kazakhstan (NSARK)/Kazakhstan.

– National Space Organization (NSPO)/Chinese Taipei.

– Naval Center for Space Technology (NCST)/USA.

– Scientific and Technological Research Council of Turkey (TUBITAK)/Turkey.

– South African National Space Agency (SANSA)/Republic of South Africa.

– Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.

– Swedish Space Corporation (SSC)/Sweden.

– Swiss Space Office (SSO)/Switzerland.

– United States Geological Survey (USGS)/USA.

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CCSDS 211.1-B-4 Page 1-5 December 2013

DOCUMENT CONTROL

Document Title Date Status

CCSDS

211.0-B-1

Proximity-1 Space Link Protocol October

2002

Original issue,

superseded

CCSDS

211.1-B-1

Proximity-1 Space Link Protocol—

Physical Layer

April

2003

Superseded

CCSDS

211.1-B-2

Proximity-1 Space Link Protocol—

Physical Layer

May

2004

Superseded

CCSDS

211.1-B-3

Proximity-1 Space Link Protocol—

Physical Layer, Recommended

Standard, Issue 3

March

2006

Superseded

CCSDS

211.1-B-4

Proximity-1 Space Link Protocol—

Physical Layer, Recommended

Standard, Issue 4

December

2013

Current issue:

This update includes

several improvements

and clarifications,

accomplishing better

alignment and

consistency with the

other Proximity-1 Blue

Books.

CCSDS

211.1-B-4

EC 1

Editorial change 1 January

2018

Repairs broken cross

reference; improves

formatting in Table of

Contents.

NOTE – Changes from the current issue are too extensive to permit markup.

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CONTENTS

Section Page

1 INTRODUCTION .......................................................................................................... 1-1

1.1 PURPOSE ............................................................................................................... 1-1

1.2 SCOPE .................................................................................................................... 1-1

1.3 APPLICABILITY ................................................................................................... 1-1

1.4 RATIONALE .......................................................................................................... 1-2

1.5 CONVENTIONS AND DEFINITIONS................................................................. 1-2

1.6 REFERENCES ....................................................................................................... 1-5

2 OVERVIEW ................................................................................................................... 2-1

2.1 PHYSICAL LAYER OVERVIEW ........................................................................ 2-1

2.2 DATA LINK LAYER OVERVIEW ...................................................................... 2-1

3 GENERAL REQUIREMENTS FOR THE PHYSICAL LAYER ............................ 3-1

3.1 RADIO EQUIPMENT ............................................................................................ 3-1

3.2 PHYSICAL LAYER FUNCTIONS ....................................................................... 3-1

3.3 CONTROLLED COMMUNICATIONS CHANNEL PROPERTIES ................... 3-5

3.4 PERFORMANCE REQUIREMENTS ................................................................... 3-9

ANNEX A PROTOCOL IMPLEMENTATION CONFORMANCE

STATEMENT PROFORMA (NORMATIVE) .......................................... A-1

ANNEX B SECURITY, SANA, AND PATENT CONSIDERATIONS

(INFORMATIVE) ..........................................................................................B-1

ANNEX C INFORMATIVE REFERENCES (INFORMATIVE) .............................. C-1

ANNEX D ABBREVIATIONS AND ACRONYMS (INFORMATIVE) .................... D-1

Figure

1-1 Proximity-1 Rate Terminology ..................................................................................... 1-5

2-1 Sim

plified Overview of Proximity-1 Layers ................................................................ 2-2

3-1 Control Variables, Signals, and Data Transfers ............................................................ 3-2

3-2 Oscillator Phase Noise

................................................................................................ 3-10

3-3 Discrete Lines Tem

plate for the Transmitter (Normalized Power in

dBc vs. Normalized Frequency: (f-f

)/A) .................................................................. 3-10

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CONTENTS (continued)

Table Page

3-1 Categories of Radio Equipment Contained on Proximity-1 Link Elements ................. 3-1

3-2 Control Variables for Transmitter ................................................................................ 3-3

3-3 Control Variables for Receiver ..................................................................................... 3-4

3-4 Proximity-1 Channel Assignments 0 through 7 (Frequencies in MHz) ....................... 3-7

A-1 Major Capabilities ....................................................................................................... A-4

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1 INTRODUCTION

1.1 PURPOSE

The purpose of this Recommended Standard is to specify Physical Layer procedures used

with the Proximity-1 Data Link Layer (references [3] and [2]). Proximity space links are

defined to be short-range, bi-directional, fixed or mobile radio links, generally used to

communicate among probes, landers, rovers, orbiting constellations, and orbiting relays.

These links are characterized by short time delays, moderate (not weak) signals, and short,

independent sessions.

1.2 SCOPE

This Recommended Standard defines the Proximity-1 Space Link Protocol Physical Layer.

The specification for the channel connection process, provision for frequency bands and

assignments, hailing channel, polarization, modulation, data rates, and performance

requirements are defined in this document.

Currently, the Physical Layer only defines operations at UHF frequencies for the Mars

environment.

The Data Link Layer is defined in the two separate CCSDS Recommended Standards entitled,

Proximity-1 Space Link Protocol—Coding and Synchronization Sublayer (reference [2]), and

Proximity-1 Space Link Protocol—Data Link Layer (reference [3]).

This Recommended Standard does not specify

a) individual implementations or products;

b) implementation of service interfaces within real systems;

c) the methods or technologies required to perform the procedures; or

d) the management activities required to configure and control the protocol.

1.3 APPLICABILITY

This Recom

mended Standard applies to the creation of Agency standards and to future data

communications over space links between CCSDS Agencies in cross-support situations. It

applies also to internal Agency links where no cross-support is required. It includes

specification of the services and protocols for inter-Agency cross support. It is neither a

specification of, nor a design for, systems that may be implemented for existing or future

missions.

The Recommended Standard specified in this document is to be invoked through the normal

standards programs of each CCSDS Agency and is applicable to those missions for which

cross support based on capabilities described in this Recommended Standard is anticipated.

Where mandatory capabilities are clearly indicated in sections of the Recommended

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Standard, they must be implemented when this document is used as a basis for cross support.

Where options are allowed or implied, implementation of these options is subject to specific

bilateral cross support agreements between the Agencies involved.

1.4 RATIONALE

The CCSDS believes it is important to document the rationale underlying the

recommendations chosen, so that future evaluations of proposed changes or improvements

will not lose sight of previous decisions. Concept and rationale behind the decisions that

formed the basis for Proximity-1 are documented in the CCSDS Proximity-1 Space Link

Protocol Green Book, reference [C1].

1.5 CONVENTIONS AND DEFINITIONS

1.5.1 DEFINITIONS

1.5.1.1 Terms from the Open Systems Interconnection (OSI) Basic Reference Model

This Recommended Standard makes use of a number of terms defined in reference [1]. In

this Recommended Standard those terms are used in a generic sense, i.e., in the sense that

those terms are generally applicable to any of a variety of technologies that provide for the

exchange of information between real systems. Those terms are as follows:

a) connection;

b) Data Link Layer;

c) Physical Layer;

d) protocol data unit;

e) real system;

f) service;

g) service data unit.

1.5.1.2 Terms Defined in This Recommended Standard

For the purposes of this Recommended Standard, the following definitions also apply. Many

other terms that pertain to specific items are defined in the appropriate sections.

caller and responder: Initiator and receiver, respectively, in a Proximity space link session.

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NOTE – A caller transceiver is the initiator of the link establishment process and

manager of negotiation (if required) of the session. A responder transceiver

typically receives link establishment parameters from the caller. The caller

initiates communication between itself and a responder on a prearranged

communications channel with predefined controlling parameters. As necessary,

the caller and responder may negotiate the controlling parameters for the session

(at some level between fully controlled and completely adaptive).

forward link: That portion of a Proximity space link in which the caller transmits and the

responder receives (typically a command link). The term ‘forward’ is used in

association with any parameters referring to the forward link.

hailing: The persistent activity used to establish a Proximity link by a caller to a responder

in either full or half duplex. It does not apply to simplex operations.

hailing channel: The forward and return frequency pairs that a caller and responder use to

establish physical link communications.

physical channel: The RF channel upon which the stream of channel symbols is transferred

over a space link in a single direction.

PLTU: Proximity Link Transmission Unit, the data unit composed of the Attached

Synchronization Marker, the Version-3 Transfer Frame, and the attached Cyclic

Redundancy Check (CRC)-32.

Proximity link: A full-duplex, half-duplex, or simplex link for the transfer of data between

Proximity-1 entities in a session.

return link: That portion of a Proximity space link in which the responder transmits and the

caller receives (typically a telemetry link). The term ‘return’ is used in association

with any parameters referring to the return link.

session: A dialog between two or more communicating Proximity link transceivers.

NOTE – A session consists of three distinct operational phases: session establishment,

data services (which may include resynchronization and/or reconnect subphases),

and session termination. Session termination can be coordinated (through the

exchange of no-more-data-to-send directives), or, if communication is lost

(inability to resynchronize or reconnect), the transceivers will eventually

independently conclude the dialog is over.

space link: A communications link between transmitting and receiving entities, at least one of

which is in space.

working channel: A forward and return frequency pair used for transferring User

data/information frames (U-frames) and Protocol/supervisory frames (P-frames)

during the data service and session termination phases.

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1.5.2 NOMENCLATURE

1.5.2.1 NORMATIVE TEXT

The following conventions apply for the normative specifications in this Recommended

Standard:

a) the words ‘shall’ and ‘must’ imply a binding and verifiable specification;

b) the word ‘should’ implies an optional, but desirable, specification;

c) the word ‘may’ implies an optional specification;

d) the words ‘is’, ‘are’, and ‘will’ imply statements of fact.

NOTE – These conventions do not imply constraints on diction in text that is clearly

informative in nature.

1.5.2.2 INFORMATIVE TEXT

In the normative section of this document (section 3), informative text is set off from the

normative specifications either in notes or under one of the following subsection headings:

– Overview;

– Background;

– Rationale;

– Discussion.

1.5.3 CONVENTIONS

Throughout this Recommended Standard, directive, parameter, variable, and signal names

are presented with all upper-case characters; data-field and MIB-parameter names are

presented with initial capitalization; values and state names are presented with predominantly

lowercase italic characters.

In Proximity-1, data rate (R

), coded symbol rate (R

) and channel symbol rate (R

chs

) are

used to denote respectively:

– the data rate of the bitstream composed by PLTUs and Idle data measured at the

encoder input;

– the coded data rate measured at the interface between the Coding and

Synchronization Sublayer and the Physical Layer; and

– the rate measured at the output of the transmitter.

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The terms are used as shown in figure 1-1.

Bi-Phase-L

MODULATOR

CHANNELBITSTREAM

FOR ENCODING

SYMBOLS

POWER AMPLIFIER

& RF CHAIN

CHANNEL

SYMBOL RATE

REFERENCE

POINT

chs

)

CODED SYMBOL RATE

CODED

SYMBOLS

REFERENCE POINT

)

ENCODER

(or Bypass)

DATA RATE

REFERENCE POINT

)

Figure 1-1: Proximity-1 Rate Terminology

With respect to the modulation scheme specified in 3.3.5.1, the following relationship applies

for the purpose of the present standard:

chs

= R

1.6 REFERENCES

The following publications contain provisions which, through reference in this text,

constitute provisions of this document. At the time of publication, the editions indicated

were valid. All publications are subject to revision, and users of this document are

encouraged to investigate the possibility of applying the most recent editions of the

publications indicated below. The CCSDS Secretariat maintains a register of currently valid

CCSDS publications.

[1] Information Technology—Open Systems Interconnection—Basic Reference Model: The

Basic Model. International Standard, ISO/IEC 7498-1:1994. 2nd ed. Geneva: ISO,

1994.

[2] Proximity-1 Space Link Protocol—Coding and Synchronization Sublayer. Issue 2.

Recommendation for Space Data System Standards (Blue Book), CCSDS 211.2-B-2.

Washington, D.C.: CCSDS, December 2013.

[3] Proximity-1 Space Link Protocol—Data Link Layer. Issue 5. Recommendation for

Space Data System Standards (Blue Book), CCSDS 211.0-B-5. Washington, D.C.:

CCSDS, December 2013.

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2 OVERVIEW

2.1 PHYSICAL LAYER OVERVIEW

Proximity-1 is a bi-directional Space Link Layer protocol for use by space missions. It

consists of a Physical Layer (the subject of this document) and a Data Link Layer (references

[2] and [3]). This protocol has been designed to meet the requirements of space missions for

efficient transfer of space data over various types and characteristics of Proximity space

links.

Proximity-1 activities are divided between a send side and a receive side. The send side is

concerned with the transmitted physical channel, and also with the acquisition of the received

physical channel in order to establish a Proximity-1 link. The operation of the transmitter is

state-driven. The receive side is concerned with the reception of data on the received

physical channel: the input symbols stream and the protocol data units it contains. Once the

receiver is turned on, its operation is modeless. It accepts and processes all valid local and

remote directives and received service data units.

On the send side, the Physical Layer:

– accepts control variables from the MAC Sublayer of the Data Link Layer for control

of the transceiver;

– accepts a coded symbols stream from the Coding & Synchronization Sublayer

(reference [2]) of the Data Link Layer for modulation onto the radiated carrier.

On the receive side, the Physical Layer:

– provides status signals (CARRIER_ACQUIRED and SYMBOL_INLOCK_STATUS)

to the MAC Sublayer of the Data Link Layer.

2.2 DATA LINK LAYER OVERVIEW

This subsection provides a brief overview of the Data Link Layer, with em

phasis on the

features relevant to the Physical Layer. For a fuller description of the overall Proximity-1

system, of the Data Link Layer and of its sublayers (see reference [3]).

On the send side, the Data Link Layer is responsible for providing the coded symbols to be

transmitted by the Physical Layer. On the receive side, the Data Link Layer accepts the

serial coded symbols stream output from the receiver in the Physical Layer and processes the

Protocol Data Units contained in it.

Within the Data Link Layer, the Medium Access Control (MAC) Sublayer (reference [3])

and the Coding and Synchronization (C&S) Sublayer (reference [2]) have interfaces to the

Physical Layer.

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The Medium Access Control (MAC) Sublayer controls the establishment, maintenance, and

termination of communications sessions for point-to-point communications between

Proximity entities. It controls the operational state of the Data Link and Physical Layers,

using control variables. It accepts Proximity-1 directives both from the local vehicle

controller and across the Proximity link to control its operations. The MAC Sublayer is also

responsible for the storage and distribution of the Management Information Base (MIB)

parameters.

On the send side, the C&S Sublayer generates the output coded symbols stream, containing

Proximity Link Transmission Units (PLTUs) and Idle data, which is delivered to the Physical

Layer for modulation onto the radiated carrier. On the receive side, the C&S Sublayer

accepts the incoming serial coded symbols stream from the Physical Layer and delimits each

PLTU contained in the symbol stream.

Figure 2-1 gives a simplified view of the relationship of the Data Link Layer to the Physical

Layer. (For a more detailed view of the Proximity-1 system, see reference [3].)

Physical Layer

Frame Sublayer

Data Services

Sublayer

I/O Sublayer

MAC

Sublayer

(MIB)

Local S/C

Controller

INPUT of USER DATA

+ Routing information

USER DATA

Delivery

SEND RECEIVE

Data Link Layer

Coding & Synchronization Layer

Figure 2-1: Simplified Overview of Proximity-1 Layers

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3 GENERAL REQUIREMENTS FOR THE PHYSICAL LAYER

3.1 RADIO EQUIPMENT

3.1.1 OVERVIEW

The Proximity-1 Link system supports the communication and navigation needs between a

variety of network elements, e.g., orbiters, landers, rovers, microprobes, balloons, aerobots,

gliders. The categories of radio equipment in network elements (E1, E2,…) are listed in

table 3-1.

3.1.2 COHERENCY REQUIREMENT

Link elements in category E2c (table 3-1), for which range and range-rate measurements are

needed, shall have transmit/receive frequency coherency capability. (See 3.4.5 for Doppler

tracking and acquisition requirements.)

Table 3-1: Categories of Radio Equipment Contained on Proximity-1 Link Elements

Category Description

E1: Elements with transmit-only capability.

E2: Elements with transmit and receive capability.

E2n: E2 elements with non-coherent mode only.

E2c: E2 elements offering in addition transmit/receive frequency coherency

capability.

E2d: E2 elements with a descoped receiver capable of receiving an FSK modulated

carrier. These elements transmit using PSK modulation.

NOTE – E2d radio equipment is intended to be used in microprobes. This option is not

required for cross support.

3.2 PHYSICAL LAYER FUNCTIONS

3.2.1 OVERVIEW

3.2.1.1 Physical Layer to Data Link Layer Interfaces

The prime function of the Physical Layer is to establish and maintain a communications

channel upon which the data can flow. To enable a physical channel connection, the

Physical Layer goes through a series of actions to establish a communications channel.

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The Physical Layer accepts control variables (MODE, DUPLEX, TRANSMIT,

MODULATION) from the MAC Sublayer of the Data Link Layer for control of the

transceiver. Reference [3] contains the specification of the actions to establish, maintain and

terminate a Proximity-1 communications session: the actions are specified in state tables and

the control variables are defined. Requirements in 3.2.2 and 3.2.3, below, complement the

specifications in reference [3].

Figure 3-1 shows the data and control flows between the Physical Layer and elements of the

Data Link Layer.

MAC sublayer

variables

MODE

DUPLEX

TRANSMIT

MODULATION

coded symbol

stream for

transmission

C&S

Physical layer

Data Link layer

signals:

CARRIER_ACQUIRED

SYMBOL_INLOCK_STATUS

received

coded symbol stream

Figure 3-1: Control Variables, Signals, and Data Transfers

3.2.1.2 Configuration of the Physical Layer

The establishment of the communications channel depends on the configuration of the

following Physical Layer parameters: frequency, polarization, modulation, acquisition, idle

sequence, and coded symbol rates, such that common operating characteristics exist in both

communicating entities.

The MAC Sublayer sets the local transceiver to the desired physical configuration, under the

control of the directives SET TRANSMITTER PARAMETERS and SET RECEIVER

PARAMETERS

. A SET PL EXTENSIONS directive is the mechanism by which additional

Physical Layer parameters defined outside of the Proximity-1 Physical Layer can be enabled

or disabled. The format and content of these and other Proximity-1 directives are specified

in an annex of reference [3].

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3.2.2 TRANSMITTER

3.2.2.1 Operational State of the Transmitter

The operational state of the transmitter shall depend on the state control variables MODE,

TRANSMIT, and MODULATION, as shown in table 3-2.

Table 3-2: Control Variables for Transmitter

MODE TRANSMIT MODULATION Transmitter state

inactive

N/A N/A

off

any value

except

inactive

off

N/A

off

on false

on, radiated output is carrier only

on true

on, data modulated onto the radiated carrier

NOTES

1 Unless MODE is inactive, a change in the value of TRANSMIT signals the Physical

Layer to transition the transmitter to on or off.

2 An MIB parameter, Carrier_Only_Duration, is used in the Data Link Layer to control

the duration of the carrier-only transmission (TRANSMIT = on and MODULATION

= false).

3 When TRANSMIT is on and MODULATION is true, the Physical Layer receives

coded symbols for transmission from the Data Link Layer (C&S Sublayer). The

content of the output coded symbols stream is specified in reference [3], which

defines an output coded sym

bols stream FIFO. The data include PLTUs and Idle

data, for example in the Acquisition sequence that is sent when transmission

commences so that the receiving unit can acquire the signal. The format of Idle data

is specified in reference [2].

3.2.3 RECEIVER

3.2.3.1 Operational State of the Receiver

The operational state of the receiver shall depend on the state control variables MODE,

DUPLEX, and TRANSMIT, as shown in table 3-3.

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Table 3-3: Control Variables for Receiver

MODE DUPLEX TRANSMIT Receiver state

inactive

N/A N/A

off

any value except

inactive

full or

simplex receive

N/A

simplex transmit

N/A

off

half on off

half off on

NOTE – The Physical Layer notifies the Data Link Layer (MAC Sublayer) of the status of

the received channel, using the signals CARRIER_ACQUIRED and

SYMBOL_INLOCK_STATUS. When SYMBOL_INLOCK_STATUS is true,

the

Physical Layer delivers the received coded symbol streams to the Data Link

Layer (C&S Sublayer).

3.2.3.2 Acquisition

The receiver shall sweep the frequency channel to which it is assigned in order to acquire

carrier lock at an assigned frequency channel.

NOTE – During this process, the receiver first attempts to lock to the carrier.

3.2.3.3

CARRIER_ACQUIRED signal

3.2.3.3.1 The

CARRIER_ACQUIRED signal shall notify the MAC Sublayer that the receiver

has acquired a carrier signal.

3.2.3.3.2 The CARRIER_ACQUIRED signal shall be set to true when the receiver is locked

to the received RF signal and false when not in lock.

3.2.3.4 SYMBOL_INLOCK_STATUS signal

3.2.3.4.1 The

SYMBOL_INLOCK_STATUS signal shall notify the MAC Sublayer that

symbol synchronization has been acquired and the received serial symbol stream is being

provided to the Data Link Layer.

3.2.3.4.2 The

SYMBOL_INLOCK_STATUS signal shall be set to true when the receiver is in

symbol lock and false when the receiver is not in symbol lock.

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NOTE – The receiver is considered to be in symbol lock when it is confident that its

symbol detection processes are synchronized to the modulated symbol stream

and the symbols output are of an acceptable quality for processing by the Data

Link Layer.

3.2.3.5 Received Symbol Stream

When SYMBOL_INLOCK_STATUS is true, the Physical Layer shall deliver the received

symbol stream to the C&S Sublayer.

NOTE – Soft symbol decisions with at least three bits quantization are recommended

whenever constraints (such as complexity of demodulator) permit.

3.3 CONTROLLED COMMUNICATIONS CHANNEL PROPERTIES

3.3.1 BACKGROUND

This Recommended Standard is designed primarily for use in a Proximity link space

environment far from Earth. The radio frequencies selected in this Recommended Standard

are designed not to cause interference to radio communication services allocated by the

Radio Regulations of the International Telecommunication Union (ITU). It should be noted

that particular precautions have to be taken to protect frequency bands allocated to Near

Earth Space Research, Deep Space, and Space Research, passive.

The frequencies specified near 430 MHz cannot be used for this purpose in the vicinity of the

Earth, and particular precautions have to be taken for equipment testing on Earth. However,

by layering appropriately, provision is made to change only the Physical Layer by adding

other frequencies to enable the same protocol to be used in near Earth applications; in the

latter case a strict compliance with the frequency allocations in the ITU Radio Regulations is

mandatory.

3.3.2 UHF FREQUENCIES

3.3.2.1 General

The frequency range for the UHF Proximity-1 links consists of 60 MHz between 390 MHz to

450 MHz with a 30 MHz guard-band between forward and return frequency bands.

3.3.2.2 Frequency Range

3.3.2.2.1 The forward frequency band shall be from 435 to 450 MHz.

3.3.2.2.2 The return frequency band shall be from 390 to 405 MHz.

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NOTES

1 Annex A of reference [3] defines the SET TRANSMITTER PARAMETERS and SET

RECEIVER PARAMETERS

directives, which are used to configure the channel

assignment for the remote vehicle’s transmitter and receiver for Channels 0 through 7.

Annex A of reference [3] also defines the SET PL EXTENSIONS directive for

Channels 8 through 15.

2 The selection of the frequencies is subject to Space Frequency Coordination Group

(SFCG) recommendations.

3.3.2.3 Hailing Channel

3.3.2.3.1 For interoperability at UHF, the default hailing channel shall be Channel 1

configured for 435.6 MHz in the forward link and 404.4 MHz in the return link (1348/44*33

turnaround ratio).

NOTE – Enterprise-specific hailing channel frequencies can be defined in the default

configuration of the Physical Layer parameters.

3.3.2.3.2 If the Proximity link radio equipment supports only a single channel (i.e., a single

forward and return frequency pair), then the hailing channel shall be the same as the working

channel (see 1.5.1.2).

3.3.2.3.3 If the Proximity link radio equipment supports multiple channels, then the hailing

channel shall be distinct from the working channel.

3.3.2.3.4 After link establishment through hailing is accomplished, transition to the

working channel (if available) should be done as soon as possible.

NOTES

1 Hailing is an activity used to establish a Proximity link with a remote vehicle.

Hailing requires the use of a hailing frequency pair.

2 Hailing is bi-directional; i.e., either element can initiate hailing. Hailing is done at a

low data rate and therefore is a low bandwidth activity. Channel 1 has been selected

to minimize the use of UHF bandwidth.

3 Hailing is performed between transceivers that are pre-configured. Therefore it is

nominally performed on the hailing channel. However, if transceivers are compatibly

configured, hailing can occur on an agreed-to channel. The first generation

transceivers are fixed frequency and use Channel 0.

4 Subsection 4.2 of reference [3] (MAC Sublayer) provides further details on hailing in

the link establishm

ent process. There are various parameters associated with the

hailing activity that are defined in the MIB. Annex B of reference [3] defines these

enterprise-specific param

eters.

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3.3.2.4 Single Forward and Single Return Frequency Pairs

NOTE – Forward and return link frequencies may be coherently related or non-coherent.

3.3.2.4.1 The following three additional channels (fixed single forward and return

frequency pairs) are defined for Proximity-1 operations:

a) Channel 0. In the case where the system requires only one return frequency,

associated with the forward 437.1 MHz frequency, the return frequency shall be

401.585625 MHz (147/160 turnaround ratio).

b) Channel 2. In the case where the system requires only one return frequency,

associated with the forward 439.2 MHz frequency, the return frequency shall be

397.5 MHz (1325/24*61 turnaround ratio).

c) Channel 3. In the case where the system requires only one return frequency,

associated with the forward 444.6 MHz frequency, the return frequency shall be

393.9 MHz (1313/38*39 turnaround ratio).

3.3.2.4.2 Table 3-4 details Proximity-1 channel assignments 0 through 7.

NOTE – Channels 8 through 15 are defined in the SET PL EXTENSIONS directive (see

annex A of reference [3]). The assignment of specific frequencies to these

channels is reserved by CCSDS.

Table 3-4: Proximity-1 Channel Assignments 0 through 7 (Frequencies in MHz)

Channel (Ch) Number Forward (F) Frequency Return (R)Frequency

0 437.1 401.585625

1 435.6 404.4

2 439.2 397.5

3 444.6 393.9

4 Within 435 to 450 Within 390 to 405

5 Within 435 to 450 Within 390 to 405

6 Within 435 to 450 Within 390 to 405

7 Within 435 to 450 Within 390 to 405

3.3.2.5 Multiple Forward and Multiple Return Frequencies

In the case where there is a need for one or multiple return frequencies paired with one or

multiple forward frequencies, the forward frequencies shall be selected from the 435 to 450

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MHz band in 20 kHz steps and the return frequencies shall be selected from 390 to 405 MHz

in 20 kHz steps. These frequency pairs shall be distinct from the frequency pairs defined in

Channels 0 through 7. The forward and return frequency components of Channels 8 through

15 are reserved for this purpose.

NOTE – Forward and return link frequencies may be coherently related or non-coherent.

3.3.3 DISCUSSION—OTHER FREQUENCY BANDS

Other frequency bands are intentionally left unspecified until a user need for them is

identified.

NOTE – If such a need arises, users are requested to contact the CCSDS Secretariat at:

[email protected].

3.3.4 POLARIZATION

Both forward and return links shall operate with Right Hand Circular Polarization (RHCP).

3.3.5 MODULATION

3.3.5.1 The PCM data shall be Bi-Phase-L encoded and modulated directly onto the carrier.

3.3.5.2 Residual carrier shall be provided with modulation index of 60° ± 5%.

3.3.5.3 The symmetry of PCM Bi-Phase-L waveforms shall be such that the mark-to-space

ratio is between 0.98 and 1.02.

3.3.5.4 A positive-going signal shall result in an advance of the phase of the radio

frequency carrier. For directly modulated Bi-phase-L waveform,

a) a symbol ‘1’ shall result in an advance of the phase of the radio frequency carrier at

the beginning of the symbol interval;

b) a symbol ‘0’ shall result in a delay.

3.3.6 PROXIMITY-1 RATES

3.3.6.1 Forward and Return Coded Symbol Rates

The Proximity-1 link shall support one or more of the following 13 discrete forward and

return values for the coded symbol rate R

shown in symbols per second: 1000, 2000, 4000,

8000, 16000, 32000, 64000, 128000, 256000, 512000, 1024000, 2048000, 4096000.

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NOTE – The correspondence between R

and R

can be found in annex A of reference [3].

The data rate R

is configured using the SET TRANSMITTER PARAMETERS,

SET RECEIVER PARAMETERS and SET PL EXTENSIONS directives defined

in annex A of reference [3]; the coded symbol rate R

is set according to the set

value of R

and to the selected coding option.

3.3.6.2 Short Term Channel Symbol Rate Stability

Each channel symbol period, as measured at the output of the transmitter, shall differ by no

more than 1% from the channel symbol period corresponding to the Proximity-1 channel

symbol rate in use.

3.3.6.3 Channel Symbol Rate Offset

Generated channel symbol rate, measured over an interval greater than 10000 symbol

periods, shall differ less than 0.1% from the defined Proximity-1 channel symbol rates as

measured at the output of the transmitter.

3.4 PERFORMANCE REQUIREMENTS

3.4.1 CARRIER FREQUENCY STABILITY REQUIREMENTS

3.4.1.1 The long-term oscillator stability (over the life of the mission) including all effects

and over all operating conditions shall be 10 ppm.

3.4.1.2 The short-term oscillator stability over 1 minute shall be 1 ppm.

3.4.2 RESIDUAL AMPLITUDE MODULATION

Residual amplitude modulation of the phase modulated RF signal shall be less than 2% RMS.

3.4.3 NON-COHERENT MODE CARRIER PHASE NOISE

In non-coherent mode, the minimum specification for the oscillator phase noise at 437.1 MHz

shall be limited by the template shown in figure 3-2.

NOTE – The figure shows normalized power in dBc (where dBc refers to the power

relative to the carrier power) vs. frequency offset from the carrier in Hz.

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Frequency in Hz

10000010000100010010

-20

-40

-60

-80

-100

-120

Phase Noise L(fm) in dBc

Figure 3-2: Oscillator Phase Noise

3.4.4 DISCRETE SPURIOUS SPECTRAL LINES

The discrete spurious spectral lines of the transmit RF signal shall be limited by the template

shown in the figure 3-3.

NOTE – The figure shows normalized power in dBc vs. normalized frequency (f-f

)/A

(where A = 2*R

, f

= carrier frequency). The factor of 2 is due to the use of Bi-

phase-L waveforms.

-70

-60

-50

-40

-30

-20

0,1 1 10 100

Figure 3-3: Discrete Spurious Spectral Lines Template for the Transmitter

(Normalized Power in dBc vs. Normalized Frequency: (f-f

)/A)

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3.4.5 DOPPLER TRACKING AND ACQUISITION REQUIREMENTS

3.4.5.1 UHF Frequencies

For the UHF frequencies specified in this Recommended Standard, the applicable Doppler

requirements shall be as follows.

a) Doppler frequency range: ±10 kHz;

b) Doppler frequency rate:

1) 100 Hz/s (non-coherent mode),

2) 200 Hz/s (coherent mode).

NOTES

1 The Doppler frequency rate does not include the Doppler rate required for tracking

canister or worst-case spacecraft-to-spacecraft cases.

2 The Doppler acquisition and tracking requirements imposed on any of the network

elements are specified according to radio frequencies employed on the link.

3 The type of Proximity Radio Equipment (table 3-1) and the vehicle type in which it

resides (e.g., orbiter, lander) will determine the applicability of capturing Doppler

Measurements.

4 The requirement applies to the RF interface between all E1 and E2 elements. In the

case of the coherent RF interface between E2c elements the effect of the coherent

turnaround ratio of the responding element has to be considered.

3.4.5.2 Discussion—Other Frequency Bands

Other frequency bands requirements are intentionally left unspecified until a user need for

them is identified.

NOTE – If such a need arises, users are requested to contact the CCSDS Secretariat at:

3[email protected].

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ANNEX A

PROTOCOL IMPLEMENTATION CONFORMANCE

STATEMENT PROFORMA

(NORMATIVE)

A1 INTRODUCTION

A1.1 OVERVIEW

This annex provides the Protocol Implementation Conformance Statement (PICS)

Requirements List (RL) for an implementation of Proximity-1 Space Link Protocol—

Physical Layer (CCSDS 211.1-B-4). The PICS for an implementation is generated by

completing the RL in accordance with the instructions below. An implementation claiming

conformance must satisfy the mandatory requirements referenced in the RL.

The RL support column in this annex is blank. An implementation’s completed RL is called

the PICS. The PICS states which capabilities and options have been implemented. The

following can use the PICS:

– the implementer, as a checklist to reduce the risk of failure to conform to the standard

through oversight;

– a supplier or potential acquirer of the implementation, as a detailed indication of the

capabilities of the implementation, stated relative to the common basis for

understanding provided by the standard PICS proforma;

– a user or potential user of the implementation, as a basis for initially checking the

possibility of interworking with another implementation (it should be noted that,

while interworking can never be guaranteed, failure to interwork can often be

predicted from incompatible PICSes);

– a tester, as the basis for selecting appropriate tests against which to assess the claim

for conformance of the implementation.

A1.2 ABBREVIATIONS AND CONVENTIONS

The RL consists of information in tabular form. The status of features is indicated using the

abbreviations and conventions described below.

Item Column

The item column contains sequential numbers for items in the table.

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Feature Column

The feature column contains a brief descriptive name for a feature. It implicitly means ‘Is

this feature supported by the implementation?’

Status Column

The status column uses the following notations:

M mandatory.

O optional.

O.<n> optional, but support of at least one of the group of options labeled by

the same numeral <n> is required.

C conditional.

C<n> conditional on ‘C<n>:’ predicate below table.

Support Column Symbols

The support column is to be used by the implementer to state whether a feature is supported

by entering Y, N, or N/A, indicating:

Y Yes, supported by the implementation.

N No, not supported by the implementation.

N/A Not applicable.

The support column should also be used, when appropriate, to enter values supported for a

given capability.

A1.3 INSTRUCTIONS FOR COMPLETING THE RL

An implementer shows the extent of compliance to the Recommended Standard by

completing the RL; that is, the state of compliance with all mandatory requirements and the

options supported are shown. The resulting completed RL is called a PICS. The implementer

shall complete the RL by entering appropriate responses in the support or values supported

column, using the notation described in A1.2. If a conditional requirement is inapplicable,

N/A should be used. If a mandatory requirement is not satisfied, exception information must

be supplied by entering a reference Xi, where i is a unique identifier, to an accompanying

rationale for the noncompliance.

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A2 PICS PROFORMA FOR PROXIMITY-1 SPACE LINK PROTOCOL—PHYSICAL

LAYER (CCSDS 211.1-B-4)

A2.1 GENERAL INFORMATION

A2.1.1 Identification of PICS

Date of Statement (DD/MM/YYYY)

PICS serial number

System Conformance statement

cross-reference

A2.1.2 Identification of Implementation Under Test (IUT)

Implementation name

Implementation version

Special Configuration

Other Information

A2.1.3 Identification of Supplier

Supplier

Contact Point for Queries

Implementation Name(s) and Versions

Other information necessary for full

identification, e.g., name(s) and version(s)

for machines and/or operating systems;

System Name(s)

A2.1.4 Identification of Specification

CCSDS 211.1-B-4

Have any exceptions been required?

NOTE – A YES answer means that the implementation does not

conform to the Recommended Standard. Non-supported

mandatory capabilities are to be identified in the PICS,

with an explanation of why the implementation is non-

conforming.

Yes [ ] No [ ]

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A2.2 REQUIREMENTS LIST

Table A-1: Major Capabilities

Item Description Reference Status

Values

Allowed

Support/Values

Implemented

1.1 Radio equipment category E1 table 3-1 O.1

1.2 Radio equipment category E2n table 3-1 O.1

1.3 Radio equipment category E2c table 3-1 O.1

1.3.1 Transmit/receive frequency

coherency capability

3.1.2 C1

(note 1)

1.4 Radio equipment category E2d table 3-1 O.1

2.1 Transmitter 3.2.2 M

2.2 Receiver 3.2.3 C2

3.1 Frequency Range (MHz) 3.3.2.2 M Forward:

from 435

to 450;

Return:

from 390

to 405

3.2 Hailing channel 3.3.2.3 M

(note 2)

Channel 1,

Channel 0,

Channel N

with N=2,

3, .. 15

3.3 Working channel(s) 3.3.2.4,

3.3.2.5

(note 3)

Channel 0

.. 15

3.3.1 Forward and return link

frequencies for channels 4, 5, ..

15 (MHz)

3.3.2.5 M Forward:

from 435

to 450 in

20 kHz

steps;

Return:

from 390

to 405 in

20 kHz

steps

4 Polarization 3.3.4 M Right Hand

Circular

5 Modulation 3.3.5 M Bi-Phase-L

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Item Description Reference Status

Values

Allowed

Support/Values

Implemented

6.1 Forward coded symbol rates

(symbols/s)

3.3.6.1 M

(note 4)

1000,

2000,

4000,

8000,

16000,

32000,

64000,

128000,

256000,

512000,

1024000,

2048000,

4096000

6.2 Return coded symbol rates

(symbols/s)

3.3.6.1 M

(note 4)

1000,

2000,

4000,

8000,

16000,

32000,

64000,

128000,

256000,

512000,

1024000,

2048000,

4096000

6.3 Short Term Channel Symbol Rate

Stability

3.3.6.2 M ≤ 1%

6.4 Channel Symbol Rate Offset 3.3.6.3 M < 0.1%

7 Performance Requirements 3.4 M

O.1: Support for one of these categories must be indicated.

C1: IF (Category = E2c) THEN M ELSE O.

C2: IF (Radio equipment category NOT E1) THEN M ELSE N/A.

NOTES

1 Mandatory for link elements in category E2c (table 3-1), for which range and range-

rate measurements are needed.

2 Channel 1 is recommended; Channel 0 is used by legacy systems; Channel N is to be

used by radios with only one channel (for hailing and working) or if agreed to.

3 The working channel has to be the same as the hailing channel for radios with only

one channel.

4 Support for at least one of the indicated 13 discrete values for the coded symbol rate

is mandatory.

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ANNEX B

SECURITY, SANA, AND PATENT CONSIDERATIONS

(INFORMATIVE)

B1 SECURITY CONSIDERATIONS

B1.1 INTRODUCTION

The security concern involves radio frequency jamming of the forward and/or return link

signal. Jamming of the signal could lead to the total loss of data, and potential navigation

errors if Doppler tracking is disrupted.

B1.2 SECURITY CONCERNS WITH RESPECT TO THE CCSDS DOCUMENT

The forward and return link signals are vulnerable to jamming, although there are several

mitigating factors. The forward signal cannot be transmitted from Earth since the currently

specified channels are reserved by ITU to other services on the Earth surface. A deliberate

attempt at jamming the forward signal in violation of the ITU regulations would disrupt a

very large number of terrestrial links in light of the difference in distances involved between

a terrestrial user and a Proximity-1 user on Mars. Concerning the return signal (received by

the orbiter in a deep space scenario), there is limited availability of equipment capable of

generating enough uplink power to effectively jam the spacecraft receiver at interplanetary

distances.

B1.3 POTENTIAL THREATS AND ATTACK SCENARIOS

Jamming of the signal could result in the loss of data or of Doppler measurements. During a

critical maneuver (e.g., probe landing on Mars), jamming could cause uncertainty in the

lander trajectory.

B1.4 CONSEQUENCES OF NOT APPLYING SECURITY TO THE

TECHNOLOGY

While these security issues are of concern, they are out of scope with respect to this

document.

Jamming denies all communications, and protection must be accomplished by Physical-

Layer techniques such as spread spectrum and/or frequency hopping. This problem is

somewhat mitigated by the amount of power and the size of antennas needed to communicate

with the spacecraft, or by the need of having a jamming source in Mars orbit.

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B2 SANA CONSIDERATION

The current issue of this Recommended Standard does not require any action from SANA.

B3 PATENT CONSIDERATIONS

No patents are known to apply to this Recommended Standard.

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ANNEX C

INFORMATIVE REFERENCES

(INFORMATIVE)

[C1] Proximity-1 Space Link Protocol—Rationale, Architecture, and Scenarios. Issue 2.

Report Concerning Space Data System Standards (Green Book), CCSDS 210.0-G-2.

Washington, D.C.: CCSDS, December 2013.

[C2] TM Synchronization and Channel Coding. Issue 2. Recommendation for Space Data

System Standards (Blue Book), CCSDS 131.0-B-2. Washington, D.C.: CCSDS, August

2011.

[C3] Radio Frequency and Modulation Systems—Part 1: Earth Stations and Spacecraft.

Issue 22. Recommendation for Space Data System Standards (Blue Book), CCSDS

401.0-B-22. Washington, D.C.: CCSDS, January 2013.

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ANNEX D

ABBREVIATIONS AND ACRONYMS

(INFORMATIVE)

C&S Coding and Synchronization

CRC Cyclic Redundancy Check

FSK Frequency-Shift Keying

ITU International Telecommunication Union

MAC Medium Access Control

MIB Management Information Base

OSI Open Systems Interconnection

PCM Pulse-Code Modulation

PLTU Proximity Link Transmission Unit

PSK Phase-Shift Keying

chs

channel symbol rate

coded symbol rate

data rate

RHCP Right Hand Circular Polarization

SANA Space Assigned Numbers Authority

SFCG Space Frequency Coordination Group