About PurePath Wireless(CC85xx)

Hi Hirokuni-san,

I don't know what you mean by TELEC. Can you please elaborate?

The hopping sequence is working like this:

The PurePath Wireless protocol has 18 RF channels in total. At any given time 4 of these are so-called active channels (A) and the remaining 14 is so-called trial channels (T). The protocol master maintains a list of all the RF channels, containing the latest history of how well they have been performing. The 4 active channels are considered to be the best performing RF channels at the moment. If any of the active channels start to decrease in performance it will be swapped out with the best performing trial channel. This trial channel will then become an active channel and the bad active channel will become a trial channel.

The time is divided in timeslots. The timeslot length depends on the application, but a typical timeslot length is 2.5ms. In this timeslot all nodes in the system send a packet (if the master packet is received by the slaves). The timeslot starts with the master sending its master packet to the slaves. Each slave sends a slave packet back to the master if it has received the master packet. Within a timeslot all nodes use the same RF channel. In the next timeslot they all use another RF channel. The sequence for RF channel usage is as follows: A1, A2, A3, A4, T1, A1, A2, A3, A4, T2, A1, A2, A3, A4, T3, .... and so on, where AX is the active channels and TX is the trial channels. So after 70 (14x5) timeslots all the 18 RF channels have been used at least one time. The reason for using the trial channels occationally is to probe their performance.

I hope this answered your question. You can find more information in the CC85xx Family User's Guide: http://www.ti.com/lit/ug/swru250k/swru250k.pdf

Best regards

Kristoffer

Dear Kristoffer

Thank you for giving an answer.

TELEC is a standard of wireless applications of Japan.

I think that this resembles FCC.

In Japan, unless it passes TELEC, wireless applications cannot be sold.

I would like to carry out an additional question.

1. About Time Slot  I got the answer of TimeSlot=2.5ms.

  I understood it as time for one channel to transmit this once.

  Is it right?

  Please let me know the value of the attached figure.

2. About Hopping  

 When connected for the first time, how are an active channel and a trial channel used?  

 Is an active channel used for the purpose of communication being established?

I beg your kindness.

Hirokuni Oota

7382.Burst Wave.pdf

Hi Hirokuni,

I have not heard of TELEC before. Has it anything to do with ARIB? That is the regulations in Japan I know of. We have designed the device to fulfill the ARIB standard, but we have not done a formal test against ARIB, but we have tested against FCC and ETSI and we have had customers passing ARIB with their designs.

1. You can read about the anatomy of a timeslot in chapter 2.4.2 in the CC85xx Family User's Guide: http://www.ti.com/lit/ug/swru250k/swru250k.pdf

Below is also an updated figure:

2. At power up the channel hopping sequence and active/trial grouping are selected from the unique device ID of the master. Thus we have the same 4 active channels and initial channel sequence each time at power up for a given master. But different masters will have different sequences and groupings.

Best regards

Kristoffer

Dear Kristoffer

Thank you. Your reply.

 I am sorry to have asked a question repeatedly.

I would like to know about arib.

I read the data of your company, such as swru250k.pdf. It was written to it that it corresponded to ARIB STANDARD T66.

If there are data which can prove conforming to ARIB STANDARD T66, I want. It is because it will be easy to do examination in Japan if there is it.

2. Thank you. Your reply about hopping.

I understood your answer about the first operation.

about active channel and trial channel

I think that I use trial channel only for checking communicative quality.

And I think that I use active channel for other all, such as data communication.

Is my thinking right?

I beg your kindness.  

Hirokuni Oota

Hi Hirokuni,

1. As I mentioned we have not done a formal test against ARIB, so I can not provide any test report proving this. However here's the link to the FCC test report of the CC85XXDK-HEADSET: 

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=417104&fcc_id='ZAT85XXHEADSET

2. Whenever a trial channel is used we treat it as any other active channel, meaning that the procedures are similar. Data is attempted to be transmitted in the trial channels as well. So it is NOT ONLY for checking communicative quality. 

Best regards

Kristoffer