FAQ: ADRadioNet - "Upstream" and "Downstream"

Document created by NagarjunaG Employee on Aug 11, 2014Last modified by carol.nelson on Sep 11, 2014
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The ADRadioNet protocol defines 10 channels in each ISM band that is supported as part of the offering. On a given node, any channel or all channels can be chosen to send data, and one channel has to be chosen for receiving the data.


Consider the following scenario, where the sensor mote (E) is sending sensor data to the Center Point (CP) via the Router (R). One may choose the first channel (or any one of the available channels) as Downstream channel - to receive the data from upper orbits, and the remaining 9 channels can be used to transmit data to lower orbits. (a.k.a Upstream Channels).



The mote (E) is sending data to the Router (R):       => on mote's Upstream channel


The Router (R) is receiving data from the mote (E):  <=  on router's Downstream channel

The Router (R) is sending data to the Center (CP):   =>  on router's Upstream channel


The Center (CP) is receiving data from Router (R):   <=  on CP's Downstream channel


Now, don't be bamboozled looking at the following statement. Take a deep breath, and digest the information

The mote (E) is receiving data from the Router (R):  <=  on router's Downstream channel, which is nothing but the mote's Upstream channel


It shall be noted that there is no downstream channel for endpoints or no upstream channel for center point. This is because the end points will be positioned in the outermost orbit and obviously won’t be allowed to receive any data from the next higher orbits. Likewise as the center point does not have any other lower orbit, it does not need any upstream channel.


In-order to have successful communication of data, at least one of the up channel frequency of the nodes in upper orbits (EP/Routers) must be equal to the down channel frequency of the lower orbits (CP/Router).The acknowledgement is sent using the same channels as the upstream data, using the channel information that was added in the packet at each hop.


This FAQ was generated from the following discussion: What is "Upstream" and "Downstream" in ADRadioNet