I am making an application for angle of arrival (AoA) estimation using LimeSDR in MIMO spatial multiplexing mode. The plan is use WiFi signal for estimating the AoA.
To estimate the angle of arrival both receive antennas should be sampling at the same time and then phase difference between the received signal is used to estimate the angle. So far I have been able to setup the board in MIMO mode using both Rx antennas.
I wrote a simple application in Octave that transmits a tone of 2.5MHz from Tx1.
The carrier frequency is 2412MHz and sampling frequency is 10MHz.
I receive the signal at both Rx1 and Rx2. However, if I plot the received signal from both antennas some times there is a delay of 1 cycle.
It seems that the there is a delay of 1 sampling clock cycle between the 2 receivers. May be there is a setting in the board configuration .ini file that I need to change. Any help would be grateful ! I can also share the code on github if that will help.
Here are my questions:
What is the best way to calibrate the LimeSDR? I already tried LimeSuite and LimeUtil --cal both of them dont make a lot of difference.
After sometime the board heats up and the performance degrades. Is this a known issue ? How can it be solved?
Has some already tried using LimeSDR in MIMO 2x2 spatial multiplexing mode?