ns in 3GPP Release 8. Beamforming was included in the 5G specifications already in the first 3GPP Release 15. Beamforming benefits are obtained in practice with massive MIMO antennas. The target is to make 5G radio design fully optimized for massive MIMO beamforming. The underlying principle of beamforming is illustrated in Figure 3.5. The traditional solution transmits data over the whole cell area while beamforming sends the data with narrow beams to the users. The same resources can be reused for multiple users within a sector, interference can be minimized, and the cell capacity can be increased. Massive MIMO is the extension of traditional MIMO technology to antenna arrays having large number of controllable transmitters. 3GPP defines massive MIMO as more than eight transmitters. Beams can be formed in number of different ways to deliver either a fixed grid of beams or user equipment (UE)-specific beamforming. If the antenna has two transceiver (TRX) branches, it can send with two parallel streams 3 Technology Components Non-beamforming Beamforming with Figure 3.5 Beamforming enhances radio capacity and transmission example 8 beams coverage. to one UE. If the antenna has four TRXs, it can send four streams to one UE having four antennas, or dual-stream to two UEs simultaneously with Multi-user Multiple Input Multiple Output (MU-MIMO). If the antenna has 64 TRXs, it can send data to multiple UEs in parallel. The number of TRXs is an important design factor in massive MIMO antennas. The greater the number of TRXs used, the more beams can be generated, which gives more capacity. But incorporating more TRXs also makes the antenna larger and increases the costs. Another important antenna design factor is the number of antenna elements, which can be greater than the number of TRXs. Figure 3.6 illustrates an example antenna with 192 elements: 12 vertical, 8 horizontal, and 2 different polarizations. The number of antenna elements defines the antenna gain and the coverage. The use of more antenna elements makes the 