Commnunication Failure and RSSI value

yoshiyuki kakishima

Other Parts Discussed in Thread: CC2590

Hi all,

In my application, CC8531 + CC2590 are used as MASTER(USB Headset) and CC8520 + CC2590 as SLAVE(Remote Headset). When they are pairing closely on sheet metal, wireless communication between them is broken. So, in order to investigate the cause, I measured RSSI value using PurePath Wireless Commander and CC debugger. I conducted RX/TX Test. Here are settings of the test and the result.

↓setting of MASTER side

↓setting of SLAVE side

The result at SLAVE is below.

In the result, the RSSI value measured in the condition that causes communication failure was about -7dBm. According to RF characteristics for CC85xx + CC2590 of CC85xx Datesheet, Saturation (maximum input level) is -12dBm. So, if the RSSI value exceeds -12dBm, is it all right at recognition that a communication failure occur?

Best regards,

Hirokuni Oota

over 13 years ago

0 Kristoffer S over 13 years ago

TI__Expert 7160 points

Hi Hirokuni,

I would say that this is expected results. -7 dBm is a way to strong signal.

-Kristoffer

0 yoshiyuki kakishima over 13 years ago in reply to Kristoffer S

Intellectual 360 points

Hi Kristoffer,

Thank you for your reply.

I have an another question.
When measuring RSSI values using RX/TX Test, what is a standard for RSSI values for good commnunication?
(For example, the RSSI value measured at a range from -50 dBm to -20 dBm is good for commnunication.)

Best regards,

Hirokuni Oota

0 Kjetil over 13 years ago in reply to yoshiyuki kakishima

TI__Mastermind 21125 points

Hi Hirokuni,

There is now standard answer per.se with regards to this. The wireless audio link will work down to the sensitivity limit, but the closer you are to this limit the more effects like multi-path and environmental changes will have on the robustness.

If anything I would say that -50 sounds a little pessimistic.

Regards,
Kjetil

0 yoshiyuki kakishima over 13 years ago in reply to Kjetil

Intellectual 360 points

Hi Kjetil,

Thank you for your answer.

Please let me change my last question.

What RSSI value (upper limit) measured in RX/TX Test causes saturation?

Best regards,

Hirokuni Oota

0 Kjetil over 13 years ago in reply to yoshiyuki kakishima

TI__Mastermind 21125 points

Hi Hirokuni,

The CC85xx saturation point is stated in the datasheet (with and without CC2590 and for both 5 Mbps and 2 Mbps).
http://www.ti.com/lit/ds/symlink/cc8530.pdf

Kjetil

0 yoshiyuki kakishima over 13 years ago in reply to Kjetil

Intellectual 360 points

Hi Kjetil and Kristoffer,

Thank you very much so far!

Best regards,

Hirokuni Oota

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Commnunication Failure and RSSI value