Design of analog Joint Source-Channel Coding systems for Broadcast Channels with MSE balancing

We consider the transmission of discrete-time continuous amplitude source information symbols over Multiple-Input Multiple-Output (MIMO) Broadcast Channels (BCs) using analog Joint Source Channel Coding (JSCC). We propose a distributed scheme that consists of single-user analog mappings concatenated with a BC access scheme specifically designed for the BC. Two different access methods are considered depending on the level of channel knowledge at transmission: Code Division Multiple Access (CDMA) and linear Minimum Mean Square Error (MMSE). The resulting analog JSCC systems are optimized to satisfy the requirements corresponding to the user MSEs and the power constraint. The idea of MSE balancing is also introduced to guarantee the feasibility of the optimization problems. Computer simulations show that CDMA provides good performance, although better results are obtained when the linear MMSE codes are employed instead of the CDMA ones.