Re: stds-802-16-tg4: Need for RF input to TG4 PHY specs
For QPSK 1/2, Turbo Codes can run as low as 2.0 SNR for the BER rage of 1e-6
to 1e9, although that is about as low as they will go for the frame sizes
under consideration. Block Turbo Codes should get pretty close to this as
well.
Obviously the SNR will increase from there as the modulation and coding
increases. Are you saying you want a table of SNR's for the various turbo
code based modulation-coding schemes (QPSK/16QAM/64QAM being proposed)?
I am sure I could generate something like that before Orlando. Let me know
if that is what you are looking for.
-Brian Edmonston
iCODING Technology Incorporated
----- Original Message -----
From: "Drayt Avera" <davera@rf-solutions.com>
To: "Brian Edmonston" <brian@icoding.com>; "Stds-802-16-Tg4@Ieee. Org"
<stds-802-16-tg4@ieee.org>
Sent: Thursday, May 03, 2001 8:47 PM
Subject: RE: stds-802-16-tg4: Need for RF input to TG4 PHY specs
> Brian,
> My goal was to determine a minimal signal level at which standard products
> will exceed a specified BER (or similar parameter). For example: -xx dBm
> for 1E-6 BER under some std conditions.
>
> The key parameters required are:
> - minimal RF front end performance (easily determined)
> - maximum SNR requirements for demod vs symbol size/rate and modulation
> (should be a table?)
> - any minimal requirements for FEC improvement (may require a standard
test
> signal or a way to disable for testing?)
>
> If all of these things add up to only 2dB, please walk me through the
> details. I'm open to other ideas on how to spec this, but this method is
> similar to that used on 802.11a (pg 31) or cell phone specs and would be
> easy to test.
>
> Drayt
>
>
> -----Original Message-----
> From: Brian Edmonston [mailto:brian@icoding.com]
> Sent: Thursday, May 03, 2001 12:17 PM
> To: Drayt Avera; Stds-802-16-Tg4@Ieee. Org
> Subject: Re: stds-802-16-tg4: Need for RF input to TG4 PHY specs
>
>
> If you want to get the range advantage of the advanced FEC I think the SNR
> target should be around 2dB.
>
> It may be preferable to make that target optional since advanced FEC will
> (most likely) be optional as well.
>
> -Brian Edmonston
>
> ----- Original Message -----
> From: Drayt Avera <davera@rf-solutions.com>
> To: Stds-802-16-Tg4@Ieee. Org <stds-802-16-tg4@ieee.org>
> Sent: Thursday, May 03, 2001 7:17 AM
> Subject: stds-802-16-tg4: Need for RF input to TG4 PHY specs
>
>
> > TG4 Team,
> > Here are some items which need to be addressed in the TG4 spec. Let's
get
> a
> > dialog started and try to solidify some numbers prior to the meeting in
a
> > few weeks.
> >
> > 1) Need specs for the expected interference conditions or protection
> > requirements. In 802.11a minimal adjacent channel specs are specified,
> and
> > I would think we would need greater interference protection. Some
> possible
> > specs to add:
> > minimum adjacent channel protection (about 40dB?) vs channel bandwidth
> > selected
> > alternate adjacent channel protection
> > TBD MHz blocking (jamming protection)
> > max expected receiver level (in-band and out of band)
> >
> > 2) Transmit or receive linearity requirements should be specified. The
> > receiver linearity will impact the system design for near/far issues.
On
> > the transmit side, maybe an EVM measurement under standard conditions
> > (similar to 802.11a) make more sense.
> >
> > 3) Need to determine a sensitivity requirement. Depending on the
> > interference and linearity requirements it should be around 5-6dB. What
> SNR
> > is required for the various modulation methods? I think a table of
> minimum
> > sensitivity vs channel bandwidth would be most appropriate.
> >
> > 4) Adjustment range for power control and any Rx AGC including response
> > characteristics and resolution. There were some previous responses
> showing
> > around 30-40dB, and it would be good to discuss the calculations that
> anyone
> > has done. 802.11a has requirements for the Tx flatness of +/-2dB.
> >
> > 5) Tx flatness: are the 802.11a requirements good enough?
> >
> > 6) Should we have a Clear Channel Assessment (CCA) type function and a
> > threshold to transmit?
> >
> > 7) TDD and FDD coexistence strategy. Are most of you are headed towards
> > TDD?
> >
> > 8) Phase noise requirement: Is this buried in the EVM measurement? It
> > would be simpler to specify it directly.
> >
> > 9) Are there any group delay requirements (absolute or variation)?
> >
> > 10) Some misc items need to be addressed:
> > temp range: same as 802.11a but add Type 4= -40 to +85C
> > Tx and Rx antenna port impedance=50ohms
> >
> > 11) What hooks are needed for frequency diversity/MIMO, etc... TJ, are
> you
> > including these in the future enhancements section?
> >
> > 12) Do you see most systems being 1 or 2 box solutions? If 2 boxes,
> should
> > add some recommended practice for standardization.
> >
> > Let's get a dialog going and I'll try to provide a coordinated input to
> the
> > PHY spec.
> >
> > Regards,
> > Drayt
> >
> >
>
>