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HI, I have a question about the packet transmission rate.
How can I change set the packet's transmission rate to a wanted value? For example, 24 Mbps instead of 6Mbps.
Currently, I changed the frame_transmit() in the wlan_mac_dcf.c file. Previously the tx_rate of a beacon was 0x0b (corresponding to 6Mbps), if I didn't change that.
Could I set this value to another value saying 0x6c (108, divided by 2 is 54, since it is in the units of 500kbps) so that the transmission rate is 54Mbps?
I tried this method, and got problems for many parameters, saying 0x12, 0x24.
I don't know if there is a special conversion between the rate and tx_rate parameter, or there are some other reasons for this problem.
Thanks very much for your help!
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That depends on what you are trying to accomplish.
If you are trying to change the rate as part of an experiment, then I would suggest that you use the WLAN Experiments Framework. You cand use the set_tx_rate_* commands to set the rate for the appropriate type of traffic. This is definitely the easiest way to change the rate if you are just looking at static rates.
If you are trying to do something more dynamic, then you can modify the transmit parameters (tx_params). First, the rate is a per-packet field that is generally decided in CPU High. You can see how the rate is processed when the MPDU is passed down to CPU Low from CPU High. As you can see, the rate value from CPU high is used as an index into a lookup table as part of the function wlan_mac_mcs_to_phy_rate(). Now, if we look at the AP as an example of CPU High code, there are default transmission parameters that are used when a new station joins an AP. Once a station joins the AP, the default transmission parameters are copied an maintained for each station. You can see an example of how to change the rate for both the defaults and all the associated stations in the AP UART menu.
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Thanks for your comments. I will follow these instructions to find my method
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