Tilt angle adaptation in LTE networks with advanced interference mitigation

In this paper we investigate the role of tilt angle adjustment in next generation LTE networks where SIMO receivers and adaptive OFDM/TDMA transmission scheduling may additionally be used to mitigate interference. We present detailed performance measurements when (i) optimal fair tilt angle adjustment is applied in combination with SIMO receivers using Linear Minimum Mean Square Error (LMMSE) detection to mitigate interference, and when (ii) tilt angle adjustment is applied in combination with proportional fair OFDM transmission scheduling which adapts the transmission rate per subcarrier (narrow-band rate allocation). We find that even when SIMO/LMMSE reception and adaptive transmission scheduling are used to mitigate interference, tilt angle adjustment still offers the potential for significant performance gains, namely increases in mean user throughput of more than 65% and improvements in the network sum-log rate of greater than 20%.