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approx-comm [2008/09/07 18:59]
sschmitt
approx-comm [2009/05/02 13:31] (current)
sdsen
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-=====Approximate communications using Software Radio.===== +**[[http://​pages.cs.wisc.edu/​~sdsen/​wiki/​doku.php?​id=old_page_apex|Older updates]]**\\ 
-The digital domain allows for much easier recovery ​of information from coherent systems. Even though ​radio channels ​are noisy and fading and difficult to work with, information can be recovered using approximation+**TODO** 
-====Setup==== +    - **Evaluate the impact ​of proposed changes to the radio pipeline(via simulations),​ ie whether the desired behavior of scrambling(consecutive sequence of 0/1 removal), interleaving(burst error mitigation) ​are hampered because of our suggested pipeline modifications.** 
-Currently, a two-USRP GNURadio setup is being used, with either differential 8-PSK or straight 8or 16-QAM. +    **Bit-mapping scheme switch (ie switching from BlockII to grey etc.) -> when to switch ​(finding a metric). Currently we just say that the h/w should have capability to estimate error rates for all schemes ​(more clarifications/methodology) ​and some results (correlation between schemesie if we estimate the errors ​for just one schemecan we predict ​the same for other schemes ?) + rate assignment??​ *
- +    ​- Better ​bit position assignment algorithmsome joint-optimization of bit position assignment and priority ​of data ??other things instead of greedy (needs more thoughts, not sure what exactly to do
-====Todo==== +    ​**Comment on delay induced by our protocol(we are buffering data), comment on the trade-off between additional delay(jitter??​) and performance benefits observedOne more knob that the application can use.** Maybe point out how the protocol ​can be opportunistic. 
-  * GNURadio: Feedback ​(non-feedforwardAGC that doesn'​t use std::max(), which should be more noise-resistant +    - Comment on throughput achieved by different ​bit-mapping schemes(as opposed to application performance). Comment on what to choose if thrpt. is the only metric. 
-  * Error data using PSK/QAM +    Do the multicast experiments as done by softcast, ie collect profiles from different ​location and show performance variation. and show that we let the users get performance commensurate with their channel conditions
-    * PSK should be taken before differential decoding ​and after differential encodingto give numbers ​for the actual effect on constellation pointsin addition to the actual values used +    Results ​for audio 
-  ​Working QAM implementation:​ +    - Other video metric like mos 
-    ​* GNURadio +**Writing Issues** 
-      * Scrambler block? ('​scrambling'​ can be on a bit level basisi.e. each bit of a 16QAM gets scrambled independentlyif that would aid us. Mason is admittedly unfamiliar with scrambling.+    - Why are selected ​error rate/ FEC rate values relevant ?(SB had commented earlier ​that the choice of evaluation seetings seem ad-hoc) 
-    * WARP +    - The MOS mapping table(from medusa).
-  ​Streaming video +
-    * On GNURadio using IP +
-    * On GNURadio using straight video transmission ​(benchmark_[tr]x.py) +
-    * On WARP +
- +
-====HelpI Don't Have the Permissions to Create a New Page for This==== +
- +
-What [[Steve]] is doing this week: +
- * Reading about how [[DSSS]] works, used in 802.11b,g to spread ​the signal in frequency Open questions are: +
-  ​How can this be used to put multiple ​bit streams with __different__ error protection into one signal? ​(__same__ error protection seems easy+
-   * sub-thought: perhaps ​by spreading ​different ​bit streams by different amounts+
-  * Is this implemented in GNU Radio? in WARP? +
-   * sub-question: where'​s the documentation ​for WARP? +
- ​* ​Assuming that QAM on GNU Radio is dead, unless a better AGC/​phase ​error calculator works magically, given that we'll have WARP radios soon.+
approx-comm.1220831954.txt.gz · Last modified: 2008/09/07 18:59 by sschmitt