The better mapper and the frequency of the "S" header bit

[Gareth Edwards <Gareth.Edwards@xxxxxxxxxx>]

Hello all,

 

In the meeting this morning there was some discussion over p7 of tf3_1508_korhonen_cpri_better_mapper_3a.pdf

 

http://www.ieee1904.org/3/meeting_archive/2015/08/tf3_1508_korhonen_cpri_better_mapper_3a.pdf

 

with Richard Maiden suggesting that the hyperframe boundary was too often and the radio frame boundary was the key synchronization point

 

I had a think about this after the call and agree with Richard on the hyperframe boundary being suboptimal for the ‘S’ bit occurrence – my only uncertainty is whether the 10ms frame or the 1ms subframe boundary is the more optimal sync point for the ‘S’ bit to appear in – probably the 10ms frame but it’s worth discussing the alternative.

 

I would guess that the reason that CPRI originally specified hyperframe boundaries was to provide a more frequent source of commas for the serdes synchronization in the physical layer, but with Ethernet providing our transport we don’t care.

 

Thanks

Gareth