Zero-Forcing Design of Precoders and Decoders in Multiuser CDMA Cooperative Networks
Consider a multiuser cooperative CDMA networks where multiple sources transmit signals toward their respective destinations with assistance of multiple relays. The authors propose joint designs of pre-coders at relays and decoders at the destinations to eliminate MAI and improve system performance. Specifically, two sub-optimal designs of pre-coders are developed to maximize SNR averaged over all users and to maximize SNR of the worst user respectively. It shows through computer simulations that the pre-coder maximizing average SNR favors the best user, while the pre-coder maximizing the minimal SNR balances radio usage of relays such that all users can achieve near-optimal diversity order.