Hi!
I have been playing with Labview Comm based MIMO Application BS and MU side. While tweaking with code I came across following few query as hurdle in further development:
1. I need a vector with channel estimate of MISO (8 antenna BS and one RRH(USRP 2952). As I understand and see from FPGA code on Flex Rio Processor the packing based on OFDM symbols make it 1200 parallel channel( for each of OFDM subcarrier) which basically means I have 6 *1200 channels to be estimated. I understand the code does estimates Resource block wise(RBs 12 per subcarrier). Which I see is packed like 4 subcarrier of antenna one after another(16 runs of channel estimate gives 4 subcarrier channel estimate on each of antenna).
I need to send noise in orthonormal basis of 16*1 channel estimate on each of the subcarrier for which I need channel estimate of 16 channel in one go. But current code gets it from local memory in different manner for precoding.
It fetches subcarrier 48 array and multiplies with channel estimates of 12 sub carrier. The precoding matrix multiplication does not take all antenna at a time but ideally we send a data from all of the antenna. We should multiply one data to all the antenna weights. Right?
Can you help me understand this precoding design and where to tweak so that I can get 16 channels each subcarrier to inject noise along with data on sub carrier?
