Optimization

MNOs must optimize their networks to support 5G. One goal is saving tower real estate by adding and consolidating antennas. For this, operators will use high-density antennas, perhaps compressing three 6-port antennas into one 18-port antenna to create room on the crowded tower for new antennas.

Massive MIMO

Massive MIMO (Multiple Input-Multiple Output) antenna architectures will be used with mid- and high-band spectrum to deliver an enhanced mobile broadband experience. The term massive MIMO is typically used when the number of antenna elements is equal to or higher than 64. As higher frequencies are used, the size of antennas decreases and hence it is feasible to fit tens or hundreds of them in a planar array within a reasonably small area (as small as the palm of a hand). By controlling each antenna or a group of antennas individually, it is possible to steer beams toward the desired direction on a per-UE (user equipment) basis.

Time Division Duplexing

5G will also likely include a significant role for Time-Division Duplex (TDD) modes. TDD and Frequency Division Duplex (FDD) are both full-duplex transmission technologies. TDD spectrum is a better fit than FDD for massive MIMO, because the reciprocal nature of the uplink and downlink make it easier to perform channel estimation as part of the beamforming process.

Interference Mitigation

Like the journeys to 3G and 4G, the RF path will be critical in the arrival of 5G, as will be the need for a high Signal to Interference Plus Noise Ratio (SINR) to ensure a robust data service. SINR has become increasingly important as the demands for high-speed data increase. The quality of the RF path is always mission-critical in a wireless network; the level of noise and interference strongly determines the data throughput. To this end, operators must focus on ensuring a clean RF path.

Wavelength Division Multiplexing (WDM)

Passive WDM optical components can have a significant impact on the efficiency of fiber fronthaul/backhaul networks. The incorporation of wavelength division multiplexers reduces the amount of fibers in the network, decreasing both the footprint and the investment cost of network rollouts. In existing networks, these components allow capacity upgrades at a relatively low cost without additional construction work.

Mobile Edge Computing

To service low-latency use cases, cloud-computing capabilities are needed at the edge of the mobile network. Mobile Edge Computing (MEC) architecture is being integrated into the 5G vision. MEC involves many smaller data centers distributed closer to the cell sites, forming an edge cloud where intelligence can be placed closer to devices and machines (Figure 2).

Figure 2: 5G networks will use Mobile Edge Computing to move intelligence closer to devices and machines.

The Road to 5G

As we have seen, moving from 4G to 5G requires myriad changes and upgrades. In general, networks will become much denser, spectrum management and virtualization will be crucial, and optimizing the network by moving parts of the radio infrastructure to the edges of the network will also be essential for supporting 5G in the future.