The application throughput obtained depends on several factors such as the traffic (application) generation rate, Network PHY (data) rate supported, number of applications, number of hops, RF channel conditions, etc.
Let us say we configure a simple Constant Bit Rate(CBR) application with a packet size of 1460 Bytes and Inter packet Arrival Time(IAT) of 1000000 microseconds. This means a traffic generation rate of 0.01 Mbps. In turn, this means, the application throughput obtained will not exceed this value, since only 0.01 Mbps of traffic is being generated at the source.
The formula for generation rate is
Generation Rate(Mbps) = ((Packet size(bytes)∗8)) / (Inter-arrival time(µs) )
The CBR (Constant Bit Rate) application generates a constant rate of traffic. Increasing the packet size or decreasing Inter packet Arrival time would increase the generation rate. For example, if you want to configure a generation rate of 1 Mbps, you could set the packet size to 1460 Bytes and set the inter-packet arrival time to 11680 microseconds.
However, generating at a higher rate does not automatically guarantee an increase in throughput. The network capacity also plays a role. In the case of a MANET network, users can increase the network capacity by changing the WLAN standard. In the wireless node properties in the wireless interface section, the WLAN standard to be used can be configured.
Each standard supports different data rates. Please refer to the following article for further details: