RIDs and Comments Submitted Against the Restructured Panel 1 Recommendations with Proposed Dispositions
Part 3: Synchronization and Channel Coding
T. Yamada, Issue 3, 30 June, 2003
Text in black was generated at the P1A meeting held in Houston in October 2002.
Text in blue was added by the editor after the meeting.
TC Synchronization and Channel Coding, CCSDS 231.0-R-1
No.
1
Page
2-3
Para
2.3.1
and
Figure
2-2
Reviewer
J. P.
Rocher
RID Short
Title
Sublayer
naming (1)
Description of Requested Change
From :
"At the sending end, the Synchronization and Channel
Coding Sublayer accepts Transfer Frames from the
Logical Link Sublayer (see figure 2-1), performs
functions ...."
C
Supporting Analysis
E
"Logical Link
Sublayer" is not
consistent with the
CCSDS Layers terms
used in paragraph 2.1
and figure 2-1.
Disposition
Accept.
Done.
To :
"At the sending end, the Synchronization and Channel
Coding Sublayer accepts Transfer Frames from the
Data Link Protocol Sublayer (see figure 2-1), performs
functions...."
2
2-3
2.3.2
W. Fong
3
2-4
2.3.2
and
figure
2.3
J. P.
Rocher
Replace "Logical Link Sublayer" by "Data Link
Protocol Sublayer" on the top of figure 2.2
From "figures" to "figure" (line 2)
Sublayer
naming (2)
From :
"At the receiving end, the Synchronization and Channel
Coding Sublayer accepts streams of channel bits
together with information on the state of the physical
communications channel from the Physical Layer,
performs functions selected for the mission, and delivers
Transfer Frames (possibly incomplete or fill bits) to the
Logical Link Sublayer."
1
E
E
"Logical Link
Sublayer" is not
consistent with the
CCSDS Layers terms
used in paragraph 2.1
and figure 2-1.
Accept.
Done.
Accept.
Done.
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Supporting Analysis
Disposition
To :
"At the receiving end, the Synchronization and Channel
Coding Sublayer accepts streams of channel bits
together with information on the state of the physical
communications channel from the Physical Layer,
performs functions selected for the mission, and delivers
Transfer Frames (possibly incomplete or fill bits) to
the Data Link Protocol Sublayer."
4
5
3-1
3-1
6
7
Table 31
Table 31
4
4-1
4.3
G. P.
Calzolari
G. P.
Calzolari
W. Fong
G. P.
FECF
Randomizer
Replace "Logical Link Sublayer" by "Data Link
Protocol Sublayer" at the top of figure 2.3
First Row in the table in section 3 gives the FECF
Optional for case 1 and desirable for case 2. Actually the
FECF is mandatory in the ESA Standard.
I think we should try to avoid the problem we are
experiencing with the TM randomizer; i.e. it may appear
we hide the risk and give people the impression that the
spirit is "use it if unavoidable" while the correct aim
should be "don't use only if you sure 150% it is not
needed".
It may be we should have stronger sentences in this
direction. BTW, I am not debating about the correctness
of your statements.
Second Row in the table in section 3 gives the
Randomizer Optional.
Same remark as above.
Section 4
(Service
Definition)
This section strikes me as being more a part of the data
link layer description.
Service
Why the parameter is Frames and not Frame?
2
Discuss.
Change "desirable" to
"optional", and explain it in
the NOTE.
Section 3 was deleted. See
comments #14 and #15 for
TM Synchronization and
Channel Coding.
Discuss.
Put a NOTE.
Section 3 was deleted. See
comments #14 and #15 for
TM Synchronization and
Channel Coding.
Discuss.
Move to an Annex.
Done.
Discuss. My observation:
No.
Page
Para
Reviewer
Calzolari
RID Short
Title
parameter
Description of Requested Change
C
I agree that it can contain several frames but..........
In addition you state that Frames at sending end consists
of one or more TC Transfer Frames. Conversely Frames
at receiving end may consist of incomplete TC Transfer
Frames. It looks confusing.
Remembering that in the 201 book we have "INPUT
DATA at sending end" & "TC DATA at receiving end"
it may be we can find something smarter.
We may discuss about ANNEX C.......
You should state it is generated at sending end (same
approach of description as you have in 4.4.3.3).
Supporting Analysis
Disposition
INPUT DATA is always
Frames. TC DATA is
always Frames (plus fill
bits or an incomplete
Frame).
Reject (see C.1.1)
8
4-2
4.4.2.3
G. P.
Calzolari
Primitive
generation
9
5-1
5.2 (last
para)
G. P.
Calzolari
Filler bit
Should we mention why the filler bit shall always be
zero? This is (or was) in principle not required, but since
we mention SEC and TED, it may be useful.
Accept. Change "service
provider" to "service
provider at the sending
end".
Done.
Discuss. The old book does
not say why. This may be a
GB issue.
10
5-2
5.4
G. P.
Calzolari
Fill bits
For TM channel coding we agreed of going octet
oriented. Should we remark that fill bits are actually
added as octets?
Reject.
Discuss. Should we call
them fill octets instead of
fill bits?
11
5-3
5.5
G. P.
Calzolari
Decoding
I think that in the green book we have the acronyms
SEC and TED. Reuse them? The 201 book only
mentions the "A: Triple error detection / B: 1-bit error
correction" within performances.
12
6-1
6.2.2
J. P.
Rocher
Missing
Sync pattern
After :
"The CLTU Start Sequence field shall delimit the start
3
E
Reject.
Accept. Insert "(Triple
Error Detection, or TED)"
after "error-detecting
mode, and "(Single Error
Correction, or SEC)" after
"error-correcting mode".
(only after the first
appearance)
Done.
Accept.
It is not missing in the
No.
Page
Para
Reviewer
RID Short
Title
of Start
Sequence!
Description of Requested Change
C
Supporting Analysis
of the encoded data within the CLTU. It consists of a
16-bit synchronization pattern with low autocorrelation
side lobes and shall have the following pattern: "
Disposition
original Word file.
Add the 16-bit sync pattern :
1 1 1 0 1 0 1 1 1 0 0 1 0 0 0 0
|
|
BIT 0
BIT 15
13
6-1
6.2.2
W. Fong
14
6-2
6.2.3
J. P.
Rocher
Clarification
& use of
'random'
Reference 16-bit pattern missing.
E
From :
"The Encoded Data field shall consist of a set of BCH
Codeblocks which have been encoded in accordance
with the BCH Codeblock encoding procedure. In
addition to error control bits, these Codeblocks contain
the Transfer frame(s), plus any fill bits that were
appended to meet codeblock length constraints. The
Encoded Data field may have been randomized before
encoding, or not randomized, as selected for the
mission. (For brevity, 'random' is used in place of
'pseudo-random' throughout this document. See annex
A.)"
E
To :
"The Encoded Data field shall consist of a set of BCH
Codeblocks which have been encoded in accordance
with the BCH Codeblock encoding procedure. In
addition to error control bits, these Codeblocks contain
the Transfer frame(s), plus any fill bits that were
appended to meet codeblock length constraints. The
Transfer Frame(s) contained in the Encoded Data field
may have been randomized before BCH encoding, or
not randomized, as selected for the mission.
4
(1) Just some minor
clarification for the
second sentence of this
paragraph.
(2) The general added
sentence on using
'random' is more
relevant to the
Overview section.
Accept.
It is not missing in the
original Word file.
Accept.
Done.
No.
15
16
Page
7-1
7-2
Para
7.1
(second
para)
7.3
Reviewer
G. P.
Calzolari
J. P.
Rocher
RID Short
Title
Randomizer
Bit
Transition
Generator
Description of Requested Change
C
Supporting Analysis
In addition, the sentence :
("For brevity, 'random' is used in place of 'pseudorandom' throughout this document. See annex A.")
should be moved in Paragraph 2.2.4 (page 2-2)
To be aligned to the formulation used in TM to be
stronger?
From :
"The randomization shall be applied at the transmitting
end, and it shall be applied only to the Transfer
Frame(s). The BTG shall be preset to the 'all-ones' state
and then shall be exclusively ORed, bit by bit, with the
Transfer Frame(s) until the process ends with the last bit
of the Transfer Frame(s) to be transmitted in a CLTU."
Disposition
Discuss. The current
sentence is very similar to
the new sentence we
adopted for TM.
E
Some additional
clarification to
mention at which time
the initialization to "all
ones" of the Pseudorandomizer shall be
performed.
Use the text by Wai.
Done.
Accept.
Done.
To :
"The randomization shall be applied at the transmitting
end, and it shall be applied only to the Transfer
Frame(s). The BTG shall be preset to the 'all-ones' state
at the start of Transfer Frame(s) and then shall be
exclusively ORed, bit by bit, with the Transfer Frame(s)
until the process ends with the last bit of the Transfer
Frame(s) to be transmitted in a CLTU."
17
9-1
Table 92
G. P.
Calzolari
Maximum
CLTU
Length
In addition, on figure 7-1, we could also change :
From :"Initialize to an "all ones" state"
to : "Initialize to an "all ones" state for each Transfer
Frame(s)"
Should we go octet oriented?
5
Accept. Change "bits" to
"octets" after Maximum
CLTU Length
No.
18
Page
C-1
19
20
Para
Reviewer
C.1.1
G. P.
Calzolari
Annex
B (old
book)
G. P.
Calzolari
Figure
B-1 (old
book)
G. P.
Calzolari
21
2-1
2.1
G. P.
Calzolari
22
2-1
Figure
G. P.
RID Short
Title
only
transfers
Transfer
Frames
Description of Requested Change
C
Suggested
Editorial
change
Correspondi
Disposition
Done.
Accept. Change "transfers"
to "accepts" (two places).
Done.
You address what the layer transfers. I think we should
address what the layer accepts (wants to be delivered)
by the upper Layer. Same story but may be reworded.
That Annex is part of the recommendation. I think we
should have preserved more from it.
CONTROL
DATA
Supporting Analysis
Discuss. Could you
recommend what should be
added to what sections?
Accept. Explain the
relationship between
Annex B of the old book
and the new Annex of the
new book.
Done. Section D1.2 was
added.
Discuss. CONTROL
DATA is not specified in
the new book because it is
not specified in the old
book, but it is mentioned at
the end of 4.1 in the new
book.
TC Channel Service Model of the Book 201 had also
CONTROL DATA at both ends (though not really
defined). Where are they now? Is your section 9
covering it (completely)?
Same as comment #3 for TM Synchronization and
Channel Coding.
E
Accept. Explain the
relationship between
Annex B of the old book
and the new Annex of the
new book.
Done. Section D1.2 was
added.
Done.
Same as comment #4 for TM Synchronization and
R
Done.
6
No.
Page
Para
Reviewer
RID Short
Title
2-1
Calzolari
G. P.
Calzolari
G. P.
Calzolari
G. P.
Calzolari
G. P.
Calzolari
ng Physical
Layer in
CCSDS
Protocols
Unclear
sentence
symbol
transition?
Change
Section 3
Repeated
information
23
2-1
2.1
24
2-3
2.2.4
25
26
3
4-2
and
4-3
4.4.2.5
and
4.4.3.5
Description of Requested Change
C
Supporting Analysis
Disposition
Channel Coding.
Same as comment #4 for TM Synchronization and
Channel Coding.
Same as comment #9 for TM Synchronization and
Channel Coding.
Same as comments #14 and #15 for TM
Synchronization and Channel Coding
Same as comments #23 and #24 for TM
Synchronization and Channel Coding
R
Done.
R
Done.
R
Section 3 was deleted.
Done.
TM Synchronization and Channel Coding, CCSDS 131.0-R-1
No.
1
Page
1-1
Para
1.1
Reviewer
F. Pollara
RID Short
Title
Purpose
Description of Requested Change
C
From: These schemes are to be used over ground-tospace or space-to-space communications links by space
missions.
To: These schemes are to be used over space-to-ground
communications links by space missions.
2
1-4
1.6.2
G. P.
Calzolari
Nomenclatu
re?
The proposed conventions are not usual to CCSDS.
Options have always been marked explicitly. Desirable
7
R
Supporting Analysis
Disposition
It seems that the TC
book "Purpose"
section was
inadvertently copied
as is into the TM
book.
By the way, I am
surprised that the titles
of these books have
acronyms in them. A
novice reader will
have a hard time
finfing the explanation
of TC and TM.
To be discussed at
CCSDS Meeting.
Accept with a
modification. This book
should also apply to spaceto-space links when relay
satellites are used. Change
the sentence to:
"These schemes are to be
used over space-to-ground
or space-to-space
communications links by
space missions.
Done. The same change
has been done in
Foreword.
Accept.
Rejected. The conventions
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Supporting Analysis
options were not identified?
Should we go back to old fashion?
3
2-1
2.1
G. P.
Calzolari
Suggested
Editorial
change
4
2-1
Figure
2-1
G. P.
Calzolari
Correspondi
ng Physical
Layer in
CCSDS
Protocols
5
2-1
2.1
G. P.
Calzolari
Unclear
sentence
6
2-2
2.2.2
G. P.
Calzolari
Scheme or
technique?
From: The TM and AOS Space Data Link Protocols
specified in references [1] and [2], respectively,
correspond to the Data Link Protocol Sublayer, and
provide functions for transferring various data using the
protocol data unit called the Transfer Frame. The
Synchronization and Channel Coding Sublayer provides
some additional functions necessary for transferring
Transfer Frames over a space link.
To: The TM and AOS Space Data Link Protocols
specified in references [1] and [2], respectively,
correspond to the Data Link Protocol Sublayer, and
provide functions for transferring data using the protocol
data unit called the Transfer Frame. The
Synchronization and Channel Coding Sublayer provides
additional functions necessary for transferring Transfer
Frames over a space link.
[Delete the words various and some.]
It is recommended adding in the third column a box for
the CCSSD PROTOCOLS corresponding Physical
Layer. It corresponds to the books on RF and
Modulation by P1E and it is particularly relevant for this
book since RF & Modulation techniques have impact on
coding and randomisation.
The following sentence is not clear:
These functions are error-control coding/decoding
(optional), Transfer Frame delimiting/synchronizing,
and bit transition generation/removal (optional).
The first row says: “This draft Recommendation
specifies the following three error-control coding
schemes:” and then 3 items are listed: convolutional, RS
& Turbo.
8
Disposition
used here are specified in
3.3.1.6 b) of the CCSDS
Publications Manual.
Accept.
Done.
E
R
Accept.
Done.
R
Which one is the real
option?
Make sentence clearer.
Accept.
Done.
T
See the Description of
Requested Change
column.
Discuss. We need a
consistent set of terms to
specify codes and
combinations of codes, but
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Supporting Analysis
what terms should be used?
Accept. Add a bullet for
the concatenated RS and
convolutional coding in
section 2.2.2.
Since the above solution
does not match the text of
this section, the word
"coding schemes" was
changed to "codes".
It may be better to use here the terms “code” or
“technique” or “coding technique” and defining as
scheme the complete coding configuration; e.g.
concatenated coding scheme. In other words a scheme
may include one or more codes.
7
2-2
2.2.2
G. P.
Calzolari
Ignoring
Punctured
convolution
al Codes
8
2-2
2.2.2
G. P.
Calzolari
Frame
Validation
in Coding
Schemes
Supporting Analysis
It is true that the “old” book said: “Several space
telemetry channel coding schemes are described in this
document.” However it also said “The characteristics of
the codes are specified only to the extent necessary to
ensure interoperability and cross-support.”
The “old” book Annex E also says “None of the coding
techniques recommended (except for the rate=1/2
convolutional code with the inverter) can by itself
guarantee sufficient transitions to keep receiver symbol
synchronizers in lock.”
Add in the descriptive part after the list the sentence
“For telecommunication channels which are bandwidthconstrained and cannot tolerate the increase in
bandwidth required by the basic convolutional code
specified in 2.1, the punctured convolutional code
specified in 2.2 has the advantage of smaller bandwidth
expansion.”
From: “Some coding schemes are also used to check
whether or not each decoded Transfer Frame can be
used as a valid data unit by the upper layers at the
receiving end. This function is called Frame Validation.
The Reed-Solomon decoder can determine, with a very
high probability, whether or not it can correctly decode
a Transfer Frame. Therefore, the Reed-Solomon code is
also used for Frame Validation. When the ReedSolomon code is not used, the Frame Error Control
Field defined in references [1] or [2] shall be used for
9
Disposition
T
This sentence is
present in the old blue
book.
Accept.
Done.
T
As mentioned, a give
coding technique may
not be able to perform
frame validation while
the complete coding
scheme will do: either
with RS or CRC
check.
Discuss.
Aside from the
terminology issue, it
should be explained that
only the R-S and CRC can
provide Frame Validation
Reject.
[Remark there is also
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Frame Validation.”
9
2-3
2.2.4
G. P.
Calzolari
symbol
transition?
2-3,
2-4
2.3.1
and
Figure
2-2
J. P.
Rocher
Sublayer
naming (1)
Disposition
an editorial change for
the “whether or not”.]
To: “All the coding schemes here defined are also used
to check whether each decoded Transfer Frame can be
used as a valid data unit by the upper layers at the
receiving end or not.”
Presently this sentence is provided: “This draft
Recommendation specifies an optional pseudorandomizer to improve bit transition density as an aid to
bit synchronization (see section 9).”
R
Should also symbol transition be mentioned?
10
Supporting Analysis
From :
"At the sending end, the Synchronization and Channel
Coding Sublayer accepts Transfer Frames of fixed
length from the Logical Link Sublayer (see figure 2-1),
performs...."
E
In fact Convolutional
Code alone ensure bit
transition (sequence of
zeros are converted to
sequences of 01);
however this is not
sufficient if QPSK is
used since the
sequence of 01
becomes a constant
sequence of the
symbol “01”.
The term "Logical
Link Sublayer" is not
consistent with the
CCSDS Layers terms
used in paragraph 2.1
and figure 2-1.
Accept and discuss the
exact wording to be used.
Use Wai's text.
Done.
The term "Logical
Link Sublayer" is not
consistent with the
Accept.
Done.
Accept.
Done.
To :
"At the sending end, the Synchronization and Channel
Coding Sublayer accepts Transfer Frames of fixed
length from the Data Link Protocol Sublayer (see figure
2-1), performs...."
11
2-4,
2-5
2.3.2
and
figure
J. P.
Rocher
Sublayer
naming (2)
Replace "Logical Link Sublayer" by "Data Link
Protocol Sublayer" on the top of figure 2.2.
From :
"At the receiving end, the Synchronization and Channel
Coding Sublayer accepts a continuous and contiguous
10
E
No.
Page
Para
Reviewer
RID Short
Title
2.3
Description of Requested Change
C
stream of channel symbols from the Physical Layer,
performs functions selected for the mission, and delivers
Transfer Frames to the Logical Link Sublayer."
Supporting Analysis
Disposition
CCSDS
Layers terms used in
paragraph 2.1 and
figure 2-1.
To :
"At the receiving end, the Synchronization and Channel
Coding Sublayer accepts a continuous and contiguous
stream of channel symbols from the Physical Layer,
performs functions selected for the mission, and delivers
Transfer Frames to the Data Link Protocol Sublayer."
12
2-3
and
2-4
2.3.1
and
2.3.2
G. P.
Calzolari
13
2-5
2.4
G. P.
Calzolari
Remove
NOTE for
recommend
combination
s
Delete
section 2.4
RECOMME
NDED
COMBINA
TIONS OF
OPTIONS
14
3
G. P.
Calzolari
Change
Section 3
15
3-1
G. P.
Randomizer
Table 3-
Replace "Logical Link Sublayer" by "Data Link
Protocol Sublayer" on the top of figure 2.3.
Remove the NOTE - For recommended combinations of
options, see section 3.
R
See previous RID.
Discuss.
Accept.
Done.
This section is not really adding information. The
suitability of a given combination of options to a
mission scenario is in principle Green Book material.
R
This section should present the allowed Schemes and
not the allowed/proposed combinations. This is Green
Book material. The (future) blue book shall only make
sure of warning the user about selection of option and
not proposing any combination as preferred=good for all
seasons.
It is said that in case 2 (convol only), the pseudo
R
11
See previous two
RIDs. The
combination of
options shall be
selected according to
mission characteristics
and not necessarily to
“augment the
performance of each
other.”
To be discussed at
CCSDS Meeting.
Accept, but whether to
delete 2.4 is independent of
whether to delete the table
of recommended
combinations of options.
Accept.
Done.
Move the table to the
Green Book.
Section 3 was deleted.
Discuss. This section was
No.
Page
Para
1
Reviewer
RID Short
Title
Calzolari
Description of Requested Change
C
Supporting Analysis
Randomiser is optional but needless though we
concluded that the conv. encoding does not guarantee
enough and 'good' transitions (e.g. if QPSK is used!).
Disposition
generated based on
requests from Agencies.
My recommendation is to
change the word "needless"
to something else and add
a note below the table.
As I already mentioned to you for the TC book I think
we should try to avoid the problem we are experiencing
with the TM randomizer; i.e. it may appear we hide
the risk and give people the impression that the spirit is
"use it if unavoidable" while the correct aim should be
"don't use only if you sure150% it is not needed". It may
be we should have stronger sentences in this direction
and avoid the word needless.
Move the table to the
Green Book.
Section 3 was deleted.
It may also be that we should completely remove that
section (valid in principle only for BPSK) from your
book in favour of the forthcoming Coding Green Book.
16
3-1,
etc.
Table
3.1,
section
9, etc.
John
O'Donnell
Randomizer
From this point of view I do invite Pen-Shu team (that
was very sensible to the Randomizer problem!) to check
the contents of the Green Book for the randomiser and
to propose any improvement they consider useful.
In Table 3-1 and in Section 9 and in other references to
the pseudo-randomizer as "needless" there should be a
change such that pseudo-randomization is denoted as
being mandatory.
Supporting analysis:
Randomization is required not only to satisfy needed
transition density for clock recovery but also to suppress
periodicity in the baseband data so as not to distort the
transmitted spectrum and also to ensure baseband
transitions for Viterbi decoding when convolutional
inner code is used. Pseudo-randomization should be
optional only if some other means are enforced to
guarantee that repetitive data patterns due to fill packets
12
T
See the Description of
Requested Change
column.
Discuss. (The same
comment as the previous
one).
Delete "needless".
Explain in the Green Book.
Section 3 was deleted. (See
comments #14 and #15.)
No.
17
Page
3-1
18
19
Para
Table 31
4
4-1
4.1.2
Reviewer
RID Short
Title
G. P.
Calzolari
C
or instrument conditions are randomized to avoid
spectral lines. Taking this step also prevents the
possibility that in a system that uses multiple branch
convocoders in the presence of long strings of fixed byte
patterns, for example 10101010, that individual branch
coders won't be coding a static input. When that
happens, and it has happened on EOS-AM (Terra), the
Viterbi decoders in the ground segment cannot reliably
acquire valid node sync because they have no baseband
transitions.
Fourth Row from Heading, Columns 3 and 5.
From “Optional but needless” to “Optional”
W. Fong
W. Fong
Description of Requested Change
Section 4
(Service
Definition)
Single User?
Supporting Analysis
Several Missions have
reported problems
with the telemetry
links although CCSDS
coding was used and
CCSDS “compliance”
was observed. These
problems could have
been avoided through
the use of the
randomizer.
This section strikes me as being more a part of the data
link layer description.
The sentence “Only one user can use this service on a
Physical Channel, and Transfer Frames from different
users are not multiplexed together within one Physical
Channel.” may be misleading. It should be improved.
13
Disposition
Discuss. (The same
comment as the previous
two comments).
Delete "needless".
Explain in the Green Book.
Section 3 was deleted. (See
comments #14 and #15.)
Discuss. (See
RIDs/comments on Table
3-1).
R
In principle AOS
Frames and Packet
TM Frames may share
the same physical Link
(as long as length &
coding are identical).
In addition several
VCs are multiplexed.
Move it to an Annex.
Done.
Reject. The sentence is not
misleading because section
4.2 of the TM (or AOS)
Space Data Link Protocol
states that the Data Link
Protocol shall generate a
sequence of Frames to be
transmitted on one
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
20
4-1
4.2.1
G. P.
Calzolari
AOS &
Packet TM
Frames not
together?
Reword this section.
R
21
4-2
4.2.3
G. P.
Calzolari
Define what
a sequence
indicator is
The sequence indicator was not defined in the past.
Nevertheless this is consistent with SLE & reality. It is
recommend stating clearly what this sequence indicator
is.
R
22
4-2
4.3.2.3
G. P.
Calzolari
Synchronou
s
ChannelAcc
ess.request?
Make clear that the ChannelAccess.request primitive is
passed synchronously to the service provider to request
it to process and send the Frame.
R
23
4-3
4.3.2.5
G. P.
Calzolari
Repeated
information
Delete this section.
E
14
Supporting Analysis
Is a VC a user? Make
clear what a user is.
In principle AOS
Frames and Packet
TM Frames may share
the same physical Link
(as long as length &
coding are identical).
Sequence Indicators
are also built by
checking the Master
Channel Counter
and/or VC Counter. In
case of coding the
sequence indicator is
normally built by
investigating timing
distance, out of lock
etc,.
In fact, the physical
layer needs to generate
frames synchronously.
It is up to the upper
layer to generate e.g.
Idle frames.
This section adds no
real information. Why
repeating? All the
information could be
in the previous
Disposition
Physical Channel.
Reject. The TM (or AOS)
Space Data Link Protocol
shall of generate all Frames
transmitted over a Physical
Channel. (Otherwise, Idle
Frames cannot be
generated.) Therefore,
AOS and TM Frames
cannot share the same
Physical Channel.
Reject. It is already defined
in this section that it
indicates a loss of frame
synchronization.
Accept. Add the following
to 4.3.2.3:
"The user shall generate
this primitive periodically
at the rate specified by the
service provider."
Done.
Accept.
Done.
No.
Page
Para
Reviewer
RID Short
Title
G. P.
Calzolari
Inconsistent
sections
Description of Requested Change
C
Supporting Analysis
Disposition
section.
24
4-3
25
6-6
26
6-6
27
7-5
28
9-1
4.3.3.4
and
4.3.3.5
6.2
W. Fong
I+M de
Lande
Long
Missing
character in
PDF
Figure
7-2
Sandi
Habinc
(Gaisler
Research)
Incorrect
Turbo
encoder
block
diagram
9.1
W. Fong
These two sections seem to be inconsistent. It may be
worth to delete the latter section and combine the
information only in one section.
Page 6-6, lines 4, 5, 10.
Dual Basis symbol (l) is missing from lines/ equations
R
On page 6-6, line 4, and again further down the page,
there are problems with one of the special characters
used in the equations. The character does not appear in
the PDF version of the file. (deLL)
The block diagram of the Turbo encoder depicts the
component encoders as 5 bits wide shift registers,
although they only have 16 states i.e. 4 bits wide
registers. The corresponding figure in CCSDS 101-0-B5 should be used instead.
E
E
T
The corresponding
figure in CCSDS 1010-B-5 has been
corrected accordingly
after some previous
discussion in the
panel.
Accept. Delete 4.3.3.5
because it repeats 4.3.3.3.
Done.
Accept. Should be handled
by the Secretariat.
It is not missing in the
original Word file.
Accept. Should be handled
by the Secretariat.
It is not missing in the
original Word file.
Accept.
Done.
Page 9-1, Section 9.1, First Paragraph:
Discuss.
From: “The pseudo-randomizer defined in this section
is required unless a sufficient bit transition density is
ensured for the channel by other methods”
Use Wai's text.
Done. The same text as
that used in Telemetry
Channel Coding Blue
Book, Issue 6 was used
wherever the randomizer
is mentioned..
To: “To ensure proper receiver operation the data
stream must be sufficiently random. The pseudorandomizer defined in this section is the preferred
method to ensure sufficient randomness for all
combinations of CCSDS recommended modulation and
coding schemes. However, a system can be compliant
without this randomizer. It is imperative that the system
designer verify proper operation of the system if this
randomizer is not used*.”
15
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Supporting Analysis
Disposition
*[footnote] Unexpected problems with telemetry links
have been encountered because this pseudo randomizer
was not used and sufficient randomness was not ensured
by other means and properly verified. See Reference
[D2] for a list of these problems to consider in the
system design.
29
10-1
10.1
G. P.
Calzolari
Minimum
Frame
Length?
30
10-1
10.2
and
10.3
G. P.
Calzolari
Why 2048?
31
10-2
10.4
G. P.
Calzolari
More info
for E
32
10-2
10.4
G. P.
Calzolari
More info
for I
33
10-2
10.4
Prof.
Garello
(through
G. P.
RS coded
Frame
lengths
[D2] Channel Coding—Summary of Concept and
Rationale. Report Concerning Space Data System
Standards, CCSDS 100.0-G-2. Green Book. Issue 2.
Washington, D.C.: CCSDS, [under development].
It looks worth to add some remarks about the minimum
frame length allowed.
R
In principle an uncoded/conv-enecoded frame may be
longer that 2048 octets. This limitation should be better
explained/clarified though it looks reasonable for data
handling (i.e. it is likely that a sw program would put the
limit to this number).
R
From:
where E = error correction capability
To:
where E = error correction capability (i.e. 8 or 16)
From:
I = interleaving depth, and
To:
I = interleaving depth (i.e. 1,….or 8), and
From:
Transfer Frame length (in octet) = (255-2E-q)I and must
be a positive integer,
where E = error correction capability,
R
Increases readability.
R
Increases readability.
16
The First Header
Pointer gives the only
real limitation.
To be discussed at
CCSDS Meeting.
Reject. This section is
about constraints on frame
lengths, which include
constraints on minimum
frame lengths.
Reject. The current Packet
Telemetry
Recommendation specifies
that the frame shall not be
longer than 2048 octets,
but it does not explain
why. A GB issue.
Reject. It is P1B's decision
(in April 2002) to use a
parameter instead of
numbers.
Reject. It is P1B's decision
(in April 2002) to use a
parameter instead of
numbers.
Discuss.
Use L for Transfer Frame
length.
No.
Page
Para
Reviewer
RID Short
Title
Calzolari)
34
10-2
10.4
G. P.
Calzolari
Description of Requested Change
q = 0 or a positive integer,
I = interleaving depth, and
qI corresponds to the number of fill octets per
codeblock.
RS coded
Frame
lengths
To:
Transfer Frame length (in octet) = (255-2E-q)I,
where E = error correction capability,
q is an integer with 0 <= q <= (255-2E-1),
I = interleaving depth, and
qI corresponds to the number of fill octets per
codeblock.
1) If I remember well the natural integers include
positive integers and the zero; than
q = 0 or a positive integer,
could be replaced by
q = natural integer,
(If this is not considered too cryptic!)
2) the upper limit (255-2E-1) is mathematically correct
but in principle would also allow - when I=1 - to have a
frame 1 byte long! Then it is illogical for I=1, but for
I=8 would allow a frame 8 bytes long (stupid but not
illegal in principle)
3) We do not have a clear lower limit for frame length a
therefore we cannot replace the value 1 with another
number an it may be that the final formulation could be:
Transfer Frame length (in octet) = k
k = (255-2E-q)I
where
E = error correction capability,
q = natural integer,
I = interleaving depth,
17
C
Supporting Analysis
Disposition
L=(255-2E-q)I
such that L is a positive
integer,
q = number of virtual fill
symbols per R-S
codeword.
delete "qI corresponds …"
Done.
Discuss. See above.
Done.
No.
Page
Para
Reviewer
RID Short
Title
Description of Requested Change
C
Supporting Analysis
Disposition
such that k > X and
qI corresponds to the number of fill octets per
codeblock
[X could correspond to the length of mandatory fields
(e.g. frame header) plus one data octet though this
would still be a crazy frame!]
35
10-2
10.4
G. P.
Calzolari
Avoid use of
may
4) Point 3 above could be in favour of simply adding "k
> X" in text form; e.g. k shall be a positive value of
reasonable length (or something similar)
Replace the word “may” with “shall” in the sentence:
When 32-bit compatibility is required, the Transfer
Frame length must be chosen so that it may be
expressed by the above equation and the codeblock
length (255-q)I (in octets) may be a multiple of 4.
R
36
10-2
10.6
G. P.
Calzolari
Correspond
I values
Include the corresponding I values as done in the old
blue book.
R
37
11-2
11
G. P.
Calzolari
Units
missing
R
38
11-3
11.6
G. P.
Calzolari
Implicit
Length
Clarify the units (e.g. bits, octets, etc.) for some
parameters as (list may be not complete):
Virtual Fill Length (Q)
Information Block Length (k)
Should the value of ASM Length (bits) implicitly be
implied by the selected coding scheme?
18
R
Discuss.
Change "codeblock length
(255-q)I"
to "R-S codeword length
(255-q)"
It shows the clear
compatibility with RS
choices.
Add note/clarification
as appropriate.
Change "may" to "shall"
Done.
Reject. The corresponding
I values are shown in table
7-1. This section is taken
from Annex E of the old
book, which does not show
the corresponding I values.
Accept. Change as follows:
(Q) => (Q, symbols)
(k) => (k, symbols)
Done.
Accept. Add the following
after table 11-5.
"NOTE: The ASM length
is determined by the
selected coding schemes."
Done.
19