[SLS-CC] Current Version of Lunar Proximity-1 Directives (SPDU type 4 & 5)

[Kazz, Greg (US 312B)]

Hi All,

Please see the current working version of the Proximity-1 Generic Session Control White Book (235x), attached.
I have updated Annex D (1st Generation Lunar) based upon Brice’s email of today along with a few updates to the SPDU Type5 found in Annex E, in which I describe the changes in detail below. Please let me know if you have any questions or concerns regarding these changes. The Type 5 directives now include the PN Ranging Directive in E2.6.

Let me point out the changes, since our last joint meeting in London in Nov. 2024.


  1.  A new one bit field, LEC Reporting/Request (LEC = Link Establishment and Control directive) has been added.



E.2.2.15          LEC Report/Request
Bit 23 of the LINK ESTABLISHMENT & CONTROL (LEC) directive tells how the LEC directive is used as a status reporting/request mechanism. It provides the radio the intrinsic capability to report the values in the LEC directive to the partnered node without a demand nor a request. It also provides a means to request that the values in the LEC directive of the partnered radio be provided to the requesting node as per below:

  1.  ‘0’ = Report LEC Values Only;
  2.  ‘1’ = Request LEC Values.
(Motivation: This version clearly distinguishes between reporting the value vs requesting the value, which didn’t exist before.)



2.     A new value for Convolutional Coding has been added to the Coding Field, to match the Prox-1 C&S book update:


E2.2.16           Coding
Bits 24–29 of the LINK ESTABLISHMENT & CONTROL directive shall contain the following coding options:

c)      ‘000010’ = Convolutional Code(7,1/2) (G2 vector inverted) with attached CRC-32 (see reference [4]);



3.     More flexibility has been added to the SNR step size for reporting the instantaneous link SNR


E2.2.18  Instantaneous Link SNR
Bits 32–39 of the LINK ESTABLISHMENT & CONTROL directive shall contain the link Signal-to-Noise Ratio (SNR), Es/N0, in dB. The unit of the step size is defined by the LINK_SNR_STEP managed parameter. See Annex F. This value is a 2s complement signed integer multiplied by the step size.
NOTE: If the step size is 0.1dB, 0x01 = 0.1dB, 0xff = -0.1dB, 0x81 = -12.7dB, 0x80 = unavailable or invalid.
(Motivation: From all of our discussions on this parameter, it seemed providing more flexibility in setting the SNR step size will make this field more operable for various classes of mission with different operating points.)


4.      Dennis Lee has formulated the PN Ranging Directive. Please see E2.6

End

Best regards,
Greg
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