Transcript of Filename -1. DARPA Spectrum Challenge - The Basics 2 1.Adversarial communications (competitive...
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- DARPA Spectrum Challenge - The Basics 2 1.Adversarial
communications (competitive tournament) Each team gets two radios
(a Tx and an Rx) Two teams (four radios) will be competing at once
Team that successfully transmits and receives give data file the
fastest wins 2.Non-adversarial Spectrum Sharing (cooperative
tournament) Four teams operate at once Multiple rounds are played
in round robin format Teams score for round is the groups score
Team with highest sum score after 10 rounds wins Each tournament
will be competed twice: Prelim competition and Final competition
Timeline Orbit Testbed 31 Jan: Register Team Feb: Complete
Qualification Hurdles Mar: Contestants announced Sep: Preliminary
Tournament Mar 2014: Final Tournament
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- Competitive Setup SDDS DARPA Packet Server 3
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- Cooperative Setup SD SD DARPA Packet Server SD 4
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- Cognitive Spectrum Operations Testbed (CSOT) Ad-hoc DSC team
formed from individuals at GTRI with an interest in SDRs Team
background Leader: Bob Baxley Comms theory Ethan Trewhitt Machine
learning, SW Andy Henshaw Tactical data links, SW Sean Nowlan
Comms, Security, GNURadio Jeff Hodges Comms, SDR
(Ettus/DRT/X-Midas) Brett Walkenhorst Comms theory Ryan Westafer
Propagation physics Chris Valenta RFID, GNURadio/Ettus SDRs DSC
& GTRI research Cognitive radio/sensing/EW SDR development
Communication theory Team Information
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- Development Logistics gr-GTRI GNURadio Module 1,842 Unique
Files 6,405 Commits Most-Changed Files 1: grc/tx_ofdm_diff.grc 2:
grc/Makefile 3: grc/rx_wreck.grc 4:
gr-GTRI/python/GTRI_wirehair_enc.py 5: gr-GTRI/grc/CMakeLists.txt
6: grc/tx.grc 7: grc/gtri_tx.py 8: grc/rx_wreck_sense.grc 9:
gr-GTRI/lib/tx_wreckC_impl.cc 10: grc/tx_inner.grc veriton-1
10.50.17.150 veriton-3 10.50.17.235 veriton-2 10.50.17.241
veriton-4 10.50.17.249 aspire-4 10.50.17.107 aspire-3 10.50.17.106
aspire-2 10.50.17.??? aspire-1 10.50.17.??? GTRI Router Lab Router
USRP N210 SBX USRP N200 SBX USRP N210 SBX USRP N200 SBX USRP B210
GTRI SDRL Testbed Grid Workflow: dsc-code_tx/rx tmux gtri_tx/rx.py
Start match: omf exec ssh grid ssh nodex-y tmux attach console
output Kill match: tmux kill-session
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- Common Waveform Elements Ns NNNN One Burst = One or more
Packets (1452 raw bytes/packet) Preamble Symbol Sense Window 255 RS
symbols K symbols One Raw Packet K= {121,132,162,182,20 8,242} File
Server Packet 1440 Bytes WH 8 bytes CR C One Coded Packet
{6,7,8,9,11,12} RS blocks/packet Start with the uncoded vector of
packets: = = Rx a subset of the Tx rows 4: Wirehair erasure code If
A is invertible, solve for x; if not, collect more symbols and try
again: Transmit that vector and then create linear combination of x
and transmit those too: (Do this forever) 1: Signal Structure 2:
Synchronization Correlation over time One Burst Ns+s 3: Sensing Tx
receives transmissions and correlates to find the sense window.
This is 600 zero samples immediately after the preamble
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- Tournament Radios: GTRI Wreck Waveform COOP (mostly-open loop):
Ramblin 64-carrier OFDM;54 occupied carriers Data is differentially
encoded across OFDM symbols; Each stream is an independent packet
54 parallel decoders at Rx Average 22 FFTs during sense window to
estimate occupancy Carriers are dynamically nulled based on
threshold; retransmit nulled Symbol-wise scaling to maximize SNDR
20s max speed; game rate is 33s Fast time: GR blocks at sample rate
( custom and canned blocks ) Slow time (20Hz): asynchronous
function probes for adaptation ( all custom) COMP (closed loop):
Wreck
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- Competitive Mode: Second Place! Our waveform adapted well,
becoming more aggressive when possible, falling back to robust when
jammed Effectively jammed many competitors by using entire band
Cooperative Mode: Effectively transmitted without colliding with
other teams Retransmitted dropped packets Only team to complete our
file in all matches Eliminated in first round due primarily to
quirks in opposing teams approaches Competition Results
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- Backup: Logo Screenshot