Will 5G small cells be able to cover large distances?

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5G is finally here! In 2019, 57 mobile operators launched commercial 5G services globally. While the 5G network roll-out is expected to continue for the next 7 – 8 years, global small cells deployment is expected to cross the 10 million mark by 2025. However, deploying hundreds of small cells in urban networks will be neither cheap nor easy for the operators. A key concern continuously looms over 5G network planners and designers – how can operators optimize their 5G investments in a way to maximize network reach while providing optimal capacity and desired latency to end customers?

Let’s look at 3 strategies that network designers consider for improving the reach of their 5G network.

  1. Efficient management of 5G spectrum: 5G needs spectrum within three key frequency ranges to deliver widespread coverage and support for all use cases.
  • Sub-1 GHz bands supports widespread coverage across urban, suburban and rural areas and help support Internet of Things (IoT) services.
  • 1- 6 GHz bands offers a good mixture of coverage and capacity benefits. This includes spectrum within the 3.3-3.8 GHz range which form the basis of many initial 5G services. It also includes other spectrum ranges such as 1.8 GHz, 2.3 GHz and 2.6 GHz etc., which may be assigned to, or refarmed by operators for enabling their 5G network.
  • Above 6 GHz bands is needed to meet the ultra-high broadband speeds envisioned for 5G. Currently, the 26 GHz and/or 28 GHz bands have the most international support in this range.

By using lower frequency bands which offer increased reach, in combination with the Above 6 GHz band (24 – 28 GHz), 5G operators can benefit from faster and cost-efficient deployment of small-cells, delivering enhanced network reach without incurring very high initial network densification costs.

 2. Use of Massive MIMO (mMIMO) and adaptive beamforming for FWA and converged Access: The most common definition of mMIMO is a system where number of antennas is greater than the number of users. By increasing the signal-to-noise ratio, mMIMO enables transmissions to travel greater distances within a given transmit power. It also increases channel capacity through the use of sophisticated adaptive properties that enable automatic signal direction lock-in and optimization of radiation patterns.

Despite the promised benefits, adoption of mMIMO and beamforming for 5G have been low. The main challenges with technology adoption are its high energy cost at site, expensive equipment and complex signalling characteristics at different frequency bands. However, both mMIMO and adaptive beamforming technologies will be fundamental to providing Fixed Wireless Access services in the 5G era.

3. Increasing front-haul reach through low-loss Optical Distribution Network (ODN): The front-haul and base-station architecture of cellular networks have changed with C-RAN. In a typical C-RAN architecture, if more small cells with Remote Radio Heads (RRHs) are covered by one Central Office (CO is where BBUs are hosted), it results in both fewer COs, and consolidation of more BBUs at any given CO. While the theoretical ODN reach between RRU and CO is up to 24.6 kms, the actual realized distance by operators is much shorter, limited by the optical power budget (15 – 20dB) and the macro-bend losses that occur in dense urban access and last-mile networks. However, operators can increase length of ODN by using bend insensitive fiber and managing this optical budget more effectivity, creating a more geographically spread front-haul network. This results in higher overall BBU pooling efficiency, and increased 5G network reach.

It is clear that an operator’s ability to leverage both radio and optical technologies to expand 5G access reach, while optimizing network CapEx will be critical. We at STL are excited to see how our customers and partners are using networking technology and design principles to build future-ready access network infrastructure. What technological disruptions will they think of next? Whatever it is, STL is committed to help operators along their unique path to 5G success.

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