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Re: [10GBT] Comparison Table Between LDPC Coded Modulation Schemes

Title: Message
Thanks Scott for your inputs,
Let me respond to each:
The assumption was floating point simulations. I did get some private feedback regarding extension to fixed point simulations and I will be working on adding complexity estimations for these. I will be updating on this.
Regarding entry #4- fine, I will add an separate entry with the base LDPC code parameters with the coded modulation scheme construction. Since we may have multilevel LDPC coded modulation construction schemes, I will add an entry of #information bits/total # bits.
Regarding entry #5- I guess we can drop that since the final decision we take will be based on the performance of any proposed scheme. I suppose that the coset partitioning will be equal for all proposals.
Entry #6 includes both encoder + decoder latency.
In entry #7, I wanted to eliminate the PAM12/PAM8 differences. In addition, I wanted to take the code rate into account, so a fair comparison would be Eb/N0. If we do confine ourselves to codes at a certain rate (more or less) and a deterministic number of PAM levels, we can compare between SNRs. I would like to get to this stage ASAP. I don't mind having an additional entry for now, but I would like to leave the Eb/N0 comparison till be narrow down the uncertainties. Same goes for #11.
I will place the number of iterations as a separate entry.
I split #10 to encoding and decoding complexity and will send an update for the encoding complexity estimation.
I have added an entry for the code construction details, which will be placed as an attachment. The description should give enough details to allow implementation of the suggested scheme.
Attached is the updated document (which I have tagged as v1.1) and which replaces the previous version.

From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Scott Powell
Sent: Wednesday, July 21, 2004 3:11 AM
Subject: Re: [10GBT] Comparison Table Between LDPC Coded Modulation Schemes

Hi Amir,
  Thanks for taking a first crack at this.  We have some initial feedback for the table you've proposed:
- Are you assuming floating point simulations for the reported results ? 
- In entry #4, this is the overall rate (bits per symbol) but there should also be an entry for the base LDPC(m,n) code parameters - block length (m) and info bits (n).
- In entry #5, are you referring to the set partitioning gain (ie: both PAM-8 and PAM-12 schemes claim a 12dB set partitioning) ?   As Prof. Lin mentioned, determining the true minimum distance of the code may not be feasible in finite time.
- In entry #6, does your definition of latency include encoder+decoder ? 
- In entry #7,  I would prefer Es/No (or SNR) rather than Eb/No (SNR per "bit") since simulations must be performed with mapped symbols - most results to date are in terms of SNR.  Also, I would suggest putting "number of iterations required" as a separate table entry since it's pretty important.
- In entry # 10, we need to include a complexity metric for the encoder as well - probably a and+xor count would suffice.
- In entry # 11, same comments on Es/No vs Eb/No data format.
- There should probably be an entry that describes the code construction as either regular or irregular, random or algebraic, and if algebraic, how the code is constructed- ie: based on RS(32,2,31) or circulant decomposition, etc ...
  - Scott
Dr. Scott Powell
Senior Manager, Ethernet PHYs
Broadcom Corp.
-----Original Message-----
From: [] On Behalf Of Mezer, Amir
Sent: Tuesday, July 20, 2004 7:02 AM
Subject: [10GBT] Comparison Table Between LDPC Coded Modulation Schemes

Hi All,

Attached is a preliminary comparison table which defines comparison criteria between the proposed schemes.

<<LDPC Coded Modulation Schemes Comparison.doc>>

In addition to the preliminary table, there are a couple of further comparison criteria (item #12 in the table) which I believe should be added in the future after the first round of comparison.

I would like to have feedback on the suggested comparison criteria and will update/refine them as we go along.


Amir Mezer


LDPC Coded Modulation Schemes Comparison v1.1.doc