The focus, in enhanced 4G and 5G network design, on an increasingly intelligent edge network, makes small cells a critical element of the platform, rather than a useful tactical solution for gaps in capacity and coverage.
The major network vendors were once ambivalent about solutions which were – in the initial small cell hype – seen as potential replacements for expensive macrocell deployments. Now times have changed. It is clear that even 5G will still have macrocell build-out, with small cells complementing that to add targeted capacity, extend coverage cost-effectively, and support private sub-nets (see previous article). Also, operators are insisting on an entirely new cost base – if their traditional suppliers do not provide commoditized low cost hardware of all shapes and sizes, they will turn to emerging vendors including the open source community as epitomized by Facebook’s Telecom Infra Project (TIP).
However, if small cells are to be the foundations of a very dense 5G network (at least in some areas such as urban centers), they not only need to be cheaper and more deployable, but they must support multi-operator and neutral host models. This will be essential for vertical and IoT sub-nets, but also to make the MNOs’ new network economics work. That will involve extensive sharing, with differentiation coming from quality of service and applications, looking ahead to network slicing. Building three or four dense small cell networks in a city or enterprise campus will not only be expensive but impossible to manage and optimize.
Technology exists to support multi-operator activities (3GPP’s MOCN and MORAN, in particular), and has been supported in commercial systems like ip.access’s enterprise-focused Viper platform. So far, however, such offerings have been only sparingly deployed and neutral host pioneers have gained limited traction. That has been largely down to MNOs’ fear of cannibalizing their own business, or their failure to see a strong business case in these sectors.
But that is starting to change. Densification has not been a priority for most operators – it has been something they knew they would have to do in preparation for 5G, or to enhance LTE services, but did not have to do urgently. That is changing, as projects by Sprint, Softbank, Reliance Jio and others indicate.
Large vendors are keen to ensure that these dense, multi-operator small cells still fit within their overall portfolios, where possible linked to their macrocells and mobile core networks – so while MNOs may dream of multivendor, interoperable small cell networks enabled by open APIs like Small Cell Forum’s FAPI and nFAPI, vendors still dream of end-to-end control, whether that is to support traditional MNO customers, private operators or enterprises.
So Nokia, in a slew of announcements geared to private networks (see above), has enhanced the features of its Flexi Zone range of small cells with neutral host in mind. For the US market, its Flexi Zone models for the 3.5 GHz CBRS band will now support the FCC-mandated Spectrum Access Server, which avoids interference in shared spectrum; plus CBRS Device Proxy connectivity to improve coverage and capacity, inside buildings. Nokia says these features enhance the ability to support neutral host capabilities, allowing operators to lease capacity to other providers inside malls, hotels and office blocks.
Other additions include self-optimizing network (SON) features and flexible backhaul options for dense networks, enabled by Carrier SDN, now implemented on its Wavence microwave backhaul range.
Crucially, all these small cell technologies are anchored by the cloud-native Nokia Cloud Packet Core, leaving the control firmly in Nokia’s hands.
For Ericsson, that point of control reaches right into the RAN. Once a great opponent of small cells, the vendor has found various ways to ensure they fit within its preferred models. It offers small cell-as-a-service (SCaaS), which puts it in the driving seat in terms of managing dense networks. And it came up with Radio Dot, a sort of hybrid between distributed small cells and DAS (distributed antenna system), which extends in-building coverage and capacity like a small cell cluster, but remains tied to the Ericsson macrocell.
And now Ericsson is meeting the need for more multi-operator choices by launching its Multi-Operator Dot. This allows one operator to manage the Dots and up to four others to provide RF signals. The Multi-Dot Enclosure combines several Dots in a single box, to improve aesthetics compared to multiple-cell approaches.
Meanwhile, the Strand Mount Unit should make it easier to deploy outdoor small cells on aerial coax, fiber or electricity cables. It can support up to four micro radios across multiple operators, to improve cost-effectiveness. All three products will go on sale next year.
Nishant Batra, head of product area network infrastructure at Ericsson, said: “With the Multi-Operator Dot and the Multi-Dot Enclosure, our customers can enhance the in-building user experience with excellent connectivity for both smartphones and IoT devices. The Strand-Mount Unit for outdoor micro radios, meanwhile, facilitates the dense deployments that will be required for 5G – enabling operators to deploy small cells in areas where they may not have been able to do so previously.”
Meanwhile, Huawei – whose LampSight offering has many similarities with Radio Dot, including the links to the macrocell – is eyeing outdoor densification projects with its new cloud access point. The AP works in unlicensed spectrum, in two 5 GHz bands, supporting LTE and future 5G-Unlicensed. It works with the Chinese firm’s CloudCampus solution for planning, optimizing and deploying small cell networks outdoors, rapidly and cost-effectively.
“Rapid development of wireless standards and cloud computing promotes continuous upgrades of campus networks. In the next few years, more enterprises will choose to migrate their campus networks to the cloud,” said Wang Shihong, general manager of Huawei’s switch & enterprise gateway product line.