Collect adjacency matrix of wifi mobile nodes

[eduardopat...@gmail.com]

Hi,

I`m building an Ad-hoc wireless network scenario of 10 nodes that change position according to randomwalk mobilty model. I`d like to know how can I collect data connectivity (or an adjacency matrix) of the nodes every 10 seconds and save it in a file. In other words, my goal is to get an output file that give me the information of which nodes were connected to each other every 10 seconds.

I found ns3::YansWifiChannel::GetNDevices, that may help me with that purpose but I do not know how to use it. 

Is there any other way to do it? Does anybody have an example of this?

Any help will be appreciate,

Thanks

Eduardo

[Tommaso Pecorella]

Hi,

there's a major flaw in your request: the idea that an adjacency matrix can exist.

The best you could have is a mutual BER matrix, and even that is meaningful only for simple scenarios (i.e., where the BER is only dependent on the mutual ode positions).

In all the other cases... you'll have issues. Big issues.

Let me list the problems:

1. The packet loss probability is dependent on the packet length. Thus, two nodes may communicate with short packets, and not with long ones.
2. The channel loss probability may be not dependent only on the nodes mutual position.
3. The packet loss is not an on/off thing, it's a probability.
4. Two nodes will be "reachable" with different degrees of goodput. It depends on the modulation and coding...
5. Etc.

Just to make things clear: check the function:

YansWifiChannel::Send (Ptr<YansWifiPhy> sender, Ptr<const Packet> packet, double txPowerDbm,
                       WifiTxVector txVector, WifiPreamble preamble) const

Each receiver (all the nodes with the same channel) will be called by it, and each node will have to decide if the packet is received correctly knowing:

1. The rx power,
2. The TxVector (details on the packet),
3. etc.

and only the receiver will know what is the probability to receive the packet.

Summarizing, first define what you mean by "adjacent", then... well, you'll have to operate a lot of simplifications.

T.

PS: mind that a node can not know how many nodes are in its surroundings unless the nodes are transmitting. I have rejected (with shame) too many papers for this idiot mistake.

Nevertheless, there's always somebody ready to say "let's assume that a node knows what are its neighbors".

[Eduardo Luengo]

Thanks Tommaso for the response and advice, I `ll try to simplify the scope and hold to the information given by the OLSR routing tables...

Regards,

Eduardo

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