Harmonization | 5G Bands

Spectrum harmonization delivers many benefits, including higher economies of scale, better battery life, improved roaming, and reduced interference along borders.

As regulators make more spectrum available, it is important that they follow guidelines such as those espoused by 4G Americas

1.       Configure licenses with wider bandwidths.

2.       Group like services together.

3.       Be mindful of global technology standards.

4.   Pursue harmonized/contiguous spectrum allocations.

5.       Exhaust exclusive use options before pursuing shared use.

6.       Because not all spectrum is fungible, align allocation with demand.

Emerging technologies such as LTE benefit from wider radio channels. These wider channels are not only spectrally more efficient, they also offer greater capacity. Figure 1 shows increasing LTE spectral efficiency obtained with wider radio channels, with 20 MHz on the downlink and 20 MHz (20+20 MHz) on the uplink showing the most efficient configuration.

Figure 1: LTE Spectral Efficiency as Function of Radio Channel Size

Of some concern in this regard is that spectrum for LTE is becoming available in different frequency bands in different countries. Roaming in many cases is based on GSM or HSPA on common regional or global bands.

The organization tasked with global spectrum harmonization, the International Telecommunication Union, periodically holds World Radiocommunications Conferences (WRC).

Harmonization occurs at multiple levels:

q  Allocation of radio frequencies to a mobile service in the ITU frequency allocation table.

q  Establishment of global or regional frequency arrangements, including channel blocks and specific duplexing modes.

q  Development of detailed technical specifications and standards, including system performance, RF performance, and coexistence with other systems in neighboring bands.

q  Assignment for frequency blocks with associated technical conditions and specifications to appropriate operators and service providers.31

Figure 2 shows the harmonization process.

Figure 2: Spectrum Harmonization

5G Bands

As radio technology progresses, it can handle higher frequencies, and it occupies greater bandwidth. 1G systems used 30 kHz radio carriers, 2G in GSM uses 200 kHz carriers, 3G in UMTS uses 5 MHz carriers, and 4G in LTE uses carriers of up to 100 MHz through carrier aggregation.

Although 5G research and development is in its infancy, to achieve the 10 Gbps or higher throughput rates envisioned for 5G will require radio carriers of at least 1 GHz, bandwidths available only at frequencies above 5 GHz. Researchers globally are studying high-frequency spectrum options. For example, the 5G organization Mobile and wireless communications Enablers for the Twenty-twenty Information Society (METIS) has published a report on spectrum needs that evaluates the following frequency bands:

q  380 to 5925 MHz (current systems)

q 5.925 MHz to 40.5 GHz

q  40.5 GHz to 95 GHz

q  95 GHz to 275 GHz (representing the upper limits of mmWave bands)

Higher frequencies are well suited for ultra-dense small-cell deployments, but longer propagation is also possible using antenna arrays and beamforming. For example, Samsung has demonstrated 2 km line-of-sight transmission at 28 GHz.