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C-Band: A Stepping Stone That Makes 5G Pervasive


C-Band: A Stepping Stone That Makes 5G Pervasive

  • Mohammed Mohiuddin

    Director of Strategy, Networks Division,
    Samsung Electronics America

Spectrum is a precious, critical resource. Today’s 5G mobile network operators use multiple spectrum ranges to meet specific network objectives. Low-band spectrum provides a good blanket of 5G coverage, while the high-band spectrum, also known as millimeter wave, delivers incredibly fast (lightning-fast) speeds due to the abundance of availiable bandwidth in hundreds of MHz. Unfortunately, a single cell operating in one of these bands can meet one of the objectives – speed or coverage, but not both. When working in lower frequencies, the cell provides expansive coverage at rates like those of current 4G LTE, but with higher performance, like lower latency between the user and radio than LTE. When functioning in high-frequencies, a cell offers very high data speeds over a much smaller coverage area.

Network operators are eager for the regulatory bodies to make mid-band frequencies available for 5G operations, as they offer efficiencies and benefits that allow mobile network operators to improve the experiences of their users. While networks in North America are leading in high-band and low-band 5G deployments, mid-band 5G deployments have only begun with one operator in 2.5GHz. Most recently, the FCC announced plans to auction mid-band spectrum called “C-Band” that will balance speed and coverage in 5G networks.

What’s All the Hype About C-Band?

In general, there are on-going discussions to free up large amount of spectrum for flexible use (fixed and mobile wireless including 5G) in the 3.0 GHz to 4.5 GHz frequency range – a range that offers a right balance of higher speeds with solid signal propagation that will help network operators provide expansive 5G coverage. C-Band comprises a portion of this frequency range, making it a prime spectrum choice that will make 5G service coverage pervasive in the US.

The FCC recently released the public notice that they will be repurposing 280 MHz of the C-Band spectrum for flexible use and conducting Auction 107 in December 2020.1

a. Block A will contain five 20-MHz sub-blocks between 3.7 GHz and 3.8 GHz

b. Block B will contain five 20-MHz sub-blocks between 3.8 GHz and 3.9 GHz

c. Block C will contain four 20-MHz sub-blocks between 3.9 GHz and 3.98 GHz

Now you might be asking yourself, what about the Citizens Broadband Radio Service (CBRS) spectrum, which is also in the 3.5GHz band? This is adjacent to the C-Band and is currently being used for LTE and with Release 16, it will be available for 5G. That said,  CBRS spectrum has some limitations in terms of its effectiveness for mobile network operators to leverage for broad 5G use. The key challenge is that under its shared licensing approach the CBRS spectrum is not universally available to network operator, so there can be times that spectrum is not available.  Secondly, due to the constrained transmitted power imposed limitation on the useful range for mobile application the typical use case for CBRS is geared toward FW (Fixed Wireless) and/or for a very small coverage area.

Now with C-Band spectrum, it offers the U.S. cricital spectrum for broad base 5G service coverage. First, users of the C-Band will have exclusive use of the blocks of the spectrum they win at Auction. Exclusivity means operators can deploy cells sites in any form and utilize them. Second, C-Band allows higher EIRP levels, which can translate into better capacity and coverage footprint offering.

These two attributes, when aligned with the 280MHz depth of C-Band spectrum, mean that operators can deploy network coverage that provides high-speed connectivity to more users with fewer cell sites.

After the auction, operators will be able to access 100MHz of C-Band for commericial use in 46 markets (partial economic areas) before or in December 2021 and 280MHz (+20MHz guard band) of C-Band will be available nationwide before or in December 2023.

Why Samsung Networks?

Samsung Networks views the C-Band spectrum as vital frequencies for 5G NR systems, and Samsung is well-positioned to support mobile network operator rollouts in the C-Band spectrum in North America. Samsung supported the first global 5G NR networks in this spectrum category, delivering Massive MIMO radios and 8T8R radios that are operating in the this critical spectrum in many markets around the world.

South Korea is a prime example, as all of the 5G network operates solely in the 3.5 GHz spectrum2. All three Korean operators are using Samsung’s 32T32R Massive MIMO radios and 8T8R radios in their network deployments. The result these network operators are using 3.5GHz across 115,000 base stations to provide 5G coverage and deliver 5G service to millions of subscribers, which, according to the country’s Ministry of Science and ICT represents a 5G penetration of 9.67%, signifying the highest penetration rate around the world3.  Samsung’s expertise in deploying and operating 5G in this mid-band spectrum will prove critical to the products being designed and deployed in the C-Band spectrum in the US.

In the U.S. to date, Samsung’s 64T64R Massive MIMO radios for CBRS and 2.5GHz bands are delivering commercial service and will provide critical foundations for a new C-Band 64T64R Massive MIMO radio. This new C-Band radio will leverage the same 64T64R antenna configuration and will adopt a new design, cooling architecture and new components to improve power management and reduce size. Among other innovations, Samsung’s C-Band products will continue using the convection cooling architecture that does not require powered fans nor fluid-based cooling systems that consume power and generate ambient noise. This product provides a high aggregated cell capacity and data throughput per user. It also provides a better containment of radiated signal due to a narrower user beam and a higher propogation range due to the high gain of the user beams thereby increasing the coverage area. By producing some of the most compact and highest performing 5G NR commercial network products in the market, Samsung’s C-band solutions will provide operators with an easy to deploy and maintain solution that delivers incredible service levels.

4 Pillars of 5G Network Evolution information image.