1. SLS AREA REPORT Goal: Next Generation Uplink WG
Develop a Green Book for Next Generation Uplink (NGU) application profiles.
Whenever possible incorporate new requirements into existing Blue books supported by the RF & Modulation, Channel Coding & Synchronization, and Link Layer protocol WGs.
If incorporation into existing Blue books is not possible, determine if a new Magenta or Blue book needs to be written.
WG Status: Active X Idle ____
WG Summary Situation: Good progress.
status: OK
CAUTION
PROBLEM
comment:
Good progress
March 2008

2. SLS AREA REPORT
NGU WG (cnt’d
NGU has handed down requirements to RF&MOD, C&S, and SLP to provide the blue book sections for the File Upload application profile i.e., for data rates > 256 Kbps to 2 Mbps. (extending existing TC standard)
Action items assigned to RF&Mod, C&S, SLP chairmen during joint meeting
RF&Mod to examine how to specify multiple access to spacecraft from one antenna on the uplink
Ground sends commands up to 4 spacecraft on one frequency
Spacecraft sweeps to acquire the uplink
Independent transponder ratio used for each spacecraft to telemeter, range, and use Doppler.
March 2008

3. Major Findings:
If a stronger code (stronger than the current BCH) was standardized for Telecommand, missions could in principle could uplink to their spacecraft at higher rates using AOS, TC, Proximity-1.
Currently no one in NGU WG can envision any agency need to simultaneously range and command on the same channel. Therefore, NGU plans on keeping ranging and telecommand on separate physical channels.
Need support from the RF&Mod WG, in ensuring that CCSDS 401 contains the requirement to allow for Multiple Spacecraft per Aperture (MSPA) on the uplink. In this case, the ground transmits up to a maximum of 4 spacecraft simultaneously using a single frequency and the spacecraft sweeps the uplink(instead of the ground) to acquire and each spacecraft has it’s own transponding ratio. In the GHz band, apparently multiple discrete turnaround ratios have been defined. The bands where these assignments need to occur are: X-band 7/8 GHz, Ka-band 34/32 GHz, Ka-band 40/38 GHz. Also CSS Forward CLTU service maybe impacted since, with the ground servicing up to 4 S/C within a single beam of an antenna, multiple POCCs maybe supplying the telecommand data to uplink. Also since the data maybe files, ARQ maybe returned from all 4 spacecraft affecting the CSS Return services. This needs to be confirmed with CSS.
March 2008

4. Major Findings Continued:
Major discussion on decoupling the frame layer from the coding sublayer for CCSDS Telecommand. Migration path identified for ESA to keep the BCH code and simultaneously run the LDPC code in the physical layer. At some future time, drop the BCH code and keep the LDPC code. This approach provides up to 8dB gain over the BCH. Only issue to resolve is how to do time correlation. Time tagging must be done in the coding sublayer i.e., One of the bits of the ASM of block code would need to time stamped., due to undeterministic delays between frame layer and coding sublayers. Time stamps would be saved into files by both the receive and send sides. Note that NASA MSL and LDCM already have implemented this capability. Strong support by NASA Mars Program has been requested of CCSDS to evaluate this proposal for standardization – in particular in light of international cross support at Mars for 2016 mission set and beyond. Note by decoupling the data link layer from the coding sublayer, it makes it possible for the coding sublayer and physical layer to be coupled, and keep the data link layer independent of both of them. This is to take advantage of advanced modulation techniques tied to channel coding.
March 2008

5. Major Findings Continued:
Application profiles have been prioritized by NGU for future requirements definition and assignment to other WGs. Priority of work is: 1) File upload (current), 2) Emergency Comm, 3) Human Support
NGU to relook at CMLP study report to mine it for more potential requirements.
Definition of discrete steps of data rates for the file upload profile seem to be needed and steps of 1.5 dB have been proposed for the file upload profile.
March 2008

6. Problems and Issues: SLS AREA REPORT None
Next Generation Uplink WG (cnt’d)
Problems and Issues:
None
March 2008

7. Planning : SLS AREA REPORT
Next Generation Uplink WG (cnt’d)
Planning :
NASA to provide a timeline for when the high rate file upload application profile is needed.
Green book descriptive information needs to be gathered for the file upload profile
Once the File upload profile is completed, the next profile should be worked on by NGU
RF&MOD WG to provide multiple transponding ratios to allow for Multiple Spacecraft per Antenna on the uplink in the bands reported in this report
March 2008

8. Resolutions : None at this time. SLS AREA REPORT
Next Generation Uplink WG (cnt’d)
Resolutions :
None at this time.
March 2008