CC1312R: CCA/LBT in Simplelink LRM application.

Andrew Bakin

Expert 1665 points

Part Number: CC1312R

Hi,

My application is based on the Collector and Sensor examples from simplelink_cc13x2_26x2_sdk_4_30_00_54.

My network is non-beacon, non_FH operating at 863MHZ. PHY = RF_CONFIG_5KBPS_868MHZ_PHY_131

I'm testing to ETSI 300 220-1 and need the CSMA-CA paramters.

Here's what I have so far:

Minimum CCA interval = 5ms?

Minimum deferral period = ?

Minimum unit of deferral period = 140us

minimum unit of deferral period = (2^CONFIG_MIN_BE - 1) * macUnitBackoffPeriod, for my application macUnitBackoffPeriod = 20 (found by searching this variable in debug mode).and CONFIG_MIN_BE == 3

Dead Time = ?

Thanks,

Andy

over 4 years ago

0 AndresM over 4 years ago

TI__Expert 3886 points

Hi Andrew,

I need to do some digging to see if the information that you want is available for the TI15.4 Stack. But may I ask how did you come up with those values so far?

BR,
Andres

0 Andrew Bakin over 4 years ago

Expert 1665 points

Hi,

Thanks for your help. I'm at the test lab now so need to move forward with something.

The figures I have already are taken from reading every post I could find on the subject in this forum. The information is very scattered so I'm not sure my approach is correct.

Many thanks,

Andy

0 AndresM over 4 years ago in reply to Andrew Bakin

TI__Expert 3886 points

Hi Andy,

Have you seen this E2E thread?

e2e.ti.com/.../3516931

Perhaps it has some of the information that you need.

BR,
Andres

0 Andrew Bakin over 4 years ago in reply to AndresM

Expert 1665 points

Hi,

Yes I have, thanks. I still need Dead Time and CCA Interval.

Thanks,

Andy

0 Andrew Bakin over 4 years ago in reply to Andrew Bakin

Expert 1665 points

Calculating maximum packet duration.

From SWRA642 application note on LRM, equation 2:

M = 2 (default I'm guessing)

N = 128 in my application

number of symbols = (M+1) * 64 + N * 8 * 2 * DSSS + 7 * 2 * DSSS

= 192 + 16320 + 56

= 16568

total packet duration = 1000000 * (number of symbols / symbol rate in Hz)

= 1000000 * (16568 / 20000)

= 828400us

= 0.8284s (standard limit is 1s)

Sub-1 GHz

Sub-1 GHz forum

CC1312R: CCA/LBT in Simplelink LRM application.