any replacement to CC2431?

thanks for that info. so, i assume location finding using RSSI is better then TI's location engine.

The location engine in the CC2431 was not TI IP, it was licensed from Motorola, and it was soley based on RSSI information from neighbors.

Indeed CC2530 is a great solution for locationing, but the location algorithm would be software instead of hardware based. The algorithm will still use RSSI, but also include correlation, and antenna diversity. A great software algorithm to be used on the centralized node (Coordinator/ Router)  is Adaptive Kalman filtering.

http://en.wikipedia.org/wiki/Kalman_filter
http://www.cs.ubc.ca/~murphyk/Software/Kalman/kalman.html
http://www.cs.unc.edu/~welch/kalman/

Data on the centralized node can be serial dump of the location data you want to use to be processed by Matlab using Kalman.

Enjoy,
LPRF Rocks the World

Hi, Dirty Harry.

I am using CC2430+ Zstack and trying to implement a simple RSSI-based tracking. I encountered the same problem described by MrGuga at this link http://e2e.ti.com/support/low_power_rf/f/158/t/17529.aspx. However, MrGuga's question was not answered in that post.

I am wondering how neighboring routers (not parent) are able to capture the RSSI/LQI of a sleeping end device? The end device could not broadcast to neighboring routers but can only indirectly send the broadcast message to its parent. Among all messages that a sleeping end device could send, only orphan notification and beacon request are broadcasts in the MAC layer.

Regards,

Yuan Jian

Hi Yuan,

In Z-stack a unit can broadcast a message, so other nodes can catch this broadcast

and extract the RSSI value. The blind node can periodically wake up and send such

broadcasts with an option of no farther retransmission of this broadcast.

Dear Igor Sherer,

Thank you for your reply. The unit in my case is a sleeping end device. I let it broadcast with destination addr - 0xfffc with radius 1. However, as I observed from the packet sniffer, this message is actually a MAC frame unicast message to its parent router. Only in its NWK frame, it is indicated as a broadcast.

As a result, all other neighbors except its parent could not get this broadcast message.

FYI. I used CC2430 with zstack-1.4.3-1.2.1. I know I must upgrade it to CC2530 so I could use the latest zstack where the neighbor table has an age bit. The old zstack I am using does not have the age bit. It only has a link quality bit but I could not know the freshness of it.

Regards,

Yuan Jian

Actually I'm not familiar with behavior of such an old stack, but from my own experience,

from Z-stack 2.3.0 and later, a broadcast of a message (broadcast address 0xfffc,

and broadcast radius = 1) works like a broadcast, no unicast messages sent to parent of

end device (in that case the sleeping device)

Hi,

Thanks for your info. That is exactly what I am looking for. I really should upgrade.

Yuan Jian

Hi, all.

I found out, in CC2430 and the Zstack 1.4.3, just use 'AF_SKIP_ROUTING' option in AF_DataRequest will do the trick.

I recently found out this solution in some other posts here.

Yuan Jian