Impact of relays and supporting nodes on locally restricted cooperation in future cellular networks

In this paper, we compare different locally restricted cooperation schemes for the downlink of LTE-Advanced. The focus in our investigations is on schemes which are easy to implement and thus have a high level of practical relevance. Two different optimization goals are considered. We first investigate how a target data rate can be achieved with lowest transmit (Tx) power. Reduction of Tx power will lead to reduced electromagnetic radiation as well as lower total power consumption of the eNodeBs. Furthermore, it will result in reduced interference between adjacent cooperation sets. We secondly maximize the data rate that can be achieved by different schemes for fixed Tx power while considering fairness between the users. Additionally, we consider implementation issues and give an estimation of achievable data rates in case of limited backhaul capacity of practical 4G networks.