Bottom Line: Sprint is accelerating its small-cell deployments with innovative strategies that capitalize on its favorable radio spectrum position. To ease radio planning challenges, Sprint has dedicated a portion of its 2600MHz TDD spectrum for small-cell access, and in some cases, has used the same spectrum band for small-cell back-haul.
For many years, Tolaga has lamented the difficulties for the mobile industry to adopt outdoor small-cells. In June 2016, Tolaga published a research report entitled, Operationalizing Small-Cells and DAS, which asserted that:
“until the mobile industry transitions from deployment and operational strategies designed for macro-cells, small-cell and DAS adoption will continue to languish despite efforts to resolve site acquisition and back-haul challenges.”
“because of the localized coverage footprints for small-cells and DAS, the level of control needed for network planning is greatly reduced relative to that for macro-cells.”
While many mobile operators position small-cells as a niche technology, this is changing. The importance of small-cells in network designs is becoming abundantly clear as operators contend with localized coverage and capacity demands. Operators that recognize the importance of small-cells and are using small-cells to densify their networks, are introducing innovative solutions to address site acquisition, planning and design and back-haul challenges. As innovative solutions are identified, they create momentum for small cell adoption. Noteworthy examples are, stealth small-cells that are integrated into street furniture such as light poles, bus shelters and existing infrastructure cabinets, and small-cells that are strand-mounted on cable plant. Other examples include, innovative small-cell designs that incorporate embedded functionality for advertising, citizens advice and Wi-Fi connectivity. These designs create value for municipalities and other entities that own and manage physical infrastructure suitable for small-cell site fixtures.
Small-cells are creating somewhat of a land-grab mentality amongst some mobile operators, who are eager to capitalize on the innovations of others. In many respects, as the variety of small-cell implementation case studies grow, they will bring the most benefit to fast-follower adopters of small-cell technology as opposed to those who are willing to push the innovation boundaries. Rather than merely following or innovating in a manner that can be replicated by their peers, we believe that it is important for operators to seek small-cell strategies that facilitate a unique advantage.
Sprint in the United States has been bucking the conventional approach towards its small-cell deployments by capitalizing on its strong spectrum position to ease planning and deployment challenges. In most markets, Sprint has 40-50MHz more spectrum than its competitors. Sprint obtained much of this spectrum from its acquisition of Clearwire in 2013, which operates in the 2600MHz band with TDD channelization. Historically, this spectrum did not carry significant intrinsic value since it was created from a tapestry of local licenses (see Tolaga Report 2010), and lacked a robust LTE device ecosystem. Nevertheless, since 2600-TDD has been adopted by major operators, including China Mobile and Sprint, a robust LTE device and infrastructure ecosystem is now in place. We believe that the vast majority of Sprint’s small-cells are supplied by Nokia.
By deploying its small-cells in a portion of dedicated 2600 TDD spectrum; Sprint does not require complicated planning between its outdoor small and macro-cells, and can be more flexible with the physical locations that it uses for small-cell placements. Spectrum constrained operators cannot pursue this strategy, but might be able to in the future if suitable spectrum, such as in the 3.5GHz band is made available.
Sprint connects some of its small-cells to nearby macro-cells using in-band 2600 TDD spectrum (i.e. UE-relay technology) to overcome back-haul challenges. From a network design perspective, this solution effectively concentrates residual macro-cell capacity into hot-spot locations where it is needed. Again, Sprint is capitalizing on its strong spectrum position to enable this solution. By using an in-band solution, Sprint can reduce the form-factor, cost and complexity of its small-cells, and ease deployment challenges. For spectrum constrained operators, the notion of dedicating access spectrum for small-cell back-haul is not feasible in urban environments. However, with more advanced macro-cellular antenna technologies, in-band solutions might become easier to implement for spectrum constrained providers, and provide a means for targeting macro-cellular capacity to localized coverage hotspots. Some operators are using in-band back-haul for small-cells in rural environments, where their macro-cellular networks are coverage limited – a compelling solution, which we believe should be more readily used.
Exhibit 1: SWOT Analysis for Sprint’s Small-Cell Strategy
Source:Tolaga Research, 2017
Conventional network design philosophies suggest that small-cells are best suited for capacity constrained network operators that lack network and spectrum resources. However, Sprint has demonstrated how it can leverage its rich spectrum position to buoy its small-cell efforts. We believe that differentiated small-cell strategies depend on operators’ ability to break from conventional network design philosophies and capitalize on their unique assets and capabilities.
About the Author
Dr. Phil Marshall