Analog joint source channel coding for block fading Multiple Access Channels

We address the transmission of discrete-time analog samples over a block fading Multiple Access Channel (MAC). We propose two practical access schemes to achieve the sum capacity of a MAC channel: opportunistic and Code Division Multiple Access (CDMA). The first one is optimal when the Channel State Information (CSI) from all users is available at all the transmitters. However, it can lead to an unfair distribution of the power and transmission rate for each user. On the other hand, the CDMA access scheme allows setting individual rate constraints while showing excellent performance when transmitting either uncompressed or compressed analog Gaussian samples.