The project in the course TSKS05 Communication Systems CDIO has been to demonstrate the capabilities of Massive MIMO in an audio environment, building upon the work done by a previous project, Massive Audio Beamforming. Using the hardware built in the previous project we have designed and implemented communication and Zero Forcing capabilities to the already existing system. The Zero Forcing and MIMO technique can ultimately be demonstrated in the implemented system by sending different data to two different terminals, simultaneously and error-free.
Brief introduction to the techniques used
The code is implemented in MATLAB and consists of 5 main modules.
We have succesfully demonstrated the concept of Zero Forcing with a MIMO tehcnique based on audio. Simultaneous error-free data transmission to two terminals has been achieved. It is even possible to transmit data to four terminals at once if an error rate of a few percent is acceptable. The main reason for not achiveing better results is the inconsistency and low performance of the hardware, higher sampling frequencies of the A/D and D/A cards would make a clear improvement on the performance. The top figure shows the received symbols when one terminal is forced to zero while we are sending data to the other. In the bottom figure the received symbols are shown for the two terminals when data is sent simultaneously to both terminals. Note that the transmission is succesful if two clusters are distinguishable except when we force the signal to zero then we want all symbols in the origin.
More extensive information can be found in the documents section.