base station beckoning to all nodes over common channel!

[vinodh123]

Hi All,

     I'm working over Routing Protocols for wireless sensor networks. Some protocols mention this, "Base station sends beckon signal to all the nodes which it can reach over a common channel" and they use the Received Signal Strength of beckon signals for further protocol formulation. So, my doubt lies in the initiating step. What does sending over common channel mean? Is it that they assume base station to know exact locations of all the nodes in network and sends them the beckon signal initially? Or is that the base station sends some messages over a common channel (say air medium) and all nodes are assumed to catch at least one of those messages and records the Received Signal Strength for further protocol formulation? Please enlighten me  over this! 

Thanks in Advance,

Vinodh

[abh]

Hello Vinodh,

Yes you can say that base station beacons to all the nodes over common channel, but actually what happens is after every 61 seconds the base station sends the message to all the nodes which is also known as Heartbeat interval for synchronizing all the nodes with it. With this the signal strength also gets updated as per my knowledge.

Cheers,

Abhinav Sharma

[Brian_A]

Abhinav, 

You are correct about NI's WSN nodes but it sounds like Vinodh is talking about wireless protocols in general. A common channel would be a defined part of the RF spectrum such as a wifi channel. Generally the radio hardware/software will be able to report back signal strength (RSSI or LQI). Once that is calculated they can send it back to the gateway and then the gateway can use the information for optimizing the network. 

Cheers,

Brian A

R & D Product Support Engineer | WSN/Network DAQ

National Instruments 

[abh]

Hello Brian sir,

As per my knowledge i don't think that we have to take care about the initiating step because beacons are started transmitting when the connection establishes and it is not in our hands to control that. the only thing which we can do to optimize the network is can take out the RSSI and calculate the signal strength in dbm and according to which we can place our nodes.

One thing i would like to ask is can we be able to access their wireless protocol they have alredy implemented