Link level performance results for physical antenna port muting in LTE are presented. In this paper we examine the block error rate performance of the LTE downlink control channels (PBCH, PCFICH, PDCCH, and the PHICH) for different antenna muting configurations. Also the throughput performance of the LTE downlink data channel (PDSCH) is studied for 2Tx and 4Tx transmit diversity formats. The results show that the combination of logical antenna port merging with physical antenna port muting provides a very minor performance loss. Since antenna muting should only be used when the traffic in a cell is low, this performance loss is not significant in practice. With antenna muting we can save energy by activating radio units only when motivated by the traffic load in the cell.