Flying Small Cells are here...

The UK mobile network operator EE has done a press release on 'Airmast technology for rural mobile coverage and disaster recovery'. The idea of having mobile base stations was first conceived by the previous CEO of EE, Olaf Swantee and then Director of RAN Mansoor Hanif in early 2015.

With the 4G small cells making it to the market in 2015/16, Mansoor brought in the  Ayan Ghosh (a.k.a. "Droneman") to lead the airmast project. While Parallel Wireless (PW) and Nokia had been actively working with EE, innovative solutions require innovative partners. This led to finding some very innovative solution providers, some of them based in the UK. Allsopp Helikites based for example is based in Salisbury who specialise in balloon deployments. Other partners included Voltserver with their smart digital power, Avanti with the satellite, UVue with their drones, Parallel Wireless with the Mesh 4G radio and Nokia with Smallcells were introduced to each other for collaboratively coming up with a solution.

The Helikite and Drone solutions are designed to provide temporary coverage not only in case of emergency but also in case of floods, power failures, fiber breaks, etc. They can also supplement the existing coverage in case of big festivals like Glastonbury, etc. In fact one of the example given by Marc Allera, CEO of EE was that anyone climbing a mountain where there may be a limited coverage can order 'coverage on demand' in future.

As part of the team to convert these innovative ideas into reality, we (Parallel Wireless) focused on small cell on the helikite with with tethered power, in-band backhaul (IBBH) and mesh link. The picture below will clarify what we have achieved.

In our case, the small cells worked in tandem with the HetNet Gateway (HNG) can self-configure and self-optimize the power, coverage, etc.

A more detailed slide from Mansoor Hanif's presentation at the Facebook TIP Summit can be seen below.

In fact to make this a success, there were many different components. Voltserver providing digital power that allows a thin cable to run along with the tether and power the small cell and other equipment on the Helikite. Having power to the helikite ensures that it can stay up for 2 - 4 weeks before being brought down to refill helium. Without this power source, 2 x 24V battery would last maybe an hour or two.

The Helikite itself by Allsopp helikites which are unique in their own way. A whitepaper by Aerostats All Australia (AAA) provides a nice comparison of different Aerostats and shows that Helikite performs better than other types, mainly in windy scenarios.

In addition to the Parallel Wireless solution, Nokia showed drones with and without the power tether and also satellite based backhaul, powered by Avanti.

From EE's press release:

EE’s breakthroughs in developing innovative aerial solutions have been achieved with the support of the most innovative partners from the mobile industry and beyond: Nokia has provided world class, lightweight, compact and portable Flexi Zone small cell basestation solutions; Parallel Wireless has delivered a unique technology with self-configuring and self-optimising basestation, in-band backhaul capability, and network meshing techniques; Avanti has enabled a fast, reliable satellite backhaul connection; VoltServer has provided touch-safe and flexible Digital Electricity power over data cable/tether; uVue has evolved drone designs to meet the specific requirements of providing mobile coverage; and Allsopp Helikites has provided the ‘Helikite’ solution that makes a stable, high altitude service possible.

The press release also notes that "EE’s tethered and powered mobile ‘air mast’ solutions are currently in patent-pending status."

Here is an interesting video from EE on how air masts will work:




My favourite picture is one posted by Mansoor Hanif on Linkedin after the first demo at BT, Madley.

Related links:

• EE Pioneers Air Mast Technology for Rural Mobile Coverage and Disaster Recovery
• Parallel Wireless and EE – Taking Small Cells to the Skies
• EE demonstrate innovative disaster recovery using small cells
• Some pictures from the EE showcase on Facebook

Related Blog Posts:

• The 3G4G Blog: An Introduction to Non-Terrestrial Networks (NTN)
• Connectivity Technology Blog: TIP has launched 'Non-Terrestrial Connectivity Solutions' Group
• The 3G4G Blog: Connectivity on Planes
• The 3G4G Blog: Satellites & Non-terrestrial networks (NTN) in 5G

*Full Disclosure: I work for Parallel Wireless as a Solutions Architect. This blog is maintained in my personal capacity and expresses my own views, not the views of my employer or anyone else. Anyone who knows me well would know this.

Multi-vendor LTE Small Cells SON

Before we proceed further, in case the reader is not aware of Self-Organizing Networks (SON), please refer to my old tutorial here.

BT has recently published a white paper on multi-vendor LTE SON based on tests using LTE small cells provided by Node-H and Qucell. From the news posted on Node-H website:

The white paper focuses on the important issue of interference management between small cells. The paper is the result of a joint effort by British Telecom's Research and Innovation group and the technical teams of Qucell and Node-H. It addresses some of the major challenges of LTE HetNets and expands on the work of the 2016 ETSI Plugfest, which was run under the auspices of the Small Cell Forum. The authors’ conclusion is that interoperability between different vendors' SON implementations is achievable and so operators can look forward to robust, seamless and tailored solutions from multiple vendors.

The white paper shows that it is possible to operate mobile networks in which the individual LTE cells execute different ICIC algorithms. These findings challenge preconceptions about SON that are common in the mobile industry and make the case towards larger multi-vendor deployments of LTE small cells and call for bolder efforts in multi-vendor SON testing.

The ICIC algorithms used during these tests have been developed independently and without exchange of technical details between two separate HeNB vendors. Despite this, it has been shown that both algorithms can gracefully co-exist in the same LTE network. ICIC standardization efforts within 3GPP, along with the Small Cell Forum's Plugfest activities, have been key to this success.

The whitepaper embedded as follows and is available to download from here:

Related posts:

• Interoperability and Plugfests for Multi-vendor HetNet's
• X2: The necessity for Interoperability and Interference management in HetNets

Wireless densification via HetNet orchestration

According to a whitepaper that was published late last year by ThinkSmallCell:

There are commonly thought to be three ways to densify wireless traffic capacity:
1. More spectrum (expensive, limited)
2. More spectrally efficiency (e.g. LTE rather than 2G)
3. More spatial reuse (i.e. small cells)
But there is also a fourth aspect which can deliver significant additional benefit
4. Orchestration and tighter control. (e.g. SON (Self Organising Networks), traffic steering/shaping across and between all available wireless resources)

This has been a key factor driving replacement of outdated macrocells with “Single RAN” basestation equipment that supports all generations of radio interface. These specifically address (1) and (2) above. What’s needed next is investment in tools and equipment that provides similar flexibility for (3) and (4), scaling to cope with an influx of small cells and introducing real-time management and co-ordination across all available wireless technologies, both cellular and Wi-Fi.

While we dont generally hear a lot about SON nowadays, I know most of the vendors have implemented some or the other aspects of SON in their equipment. Orchestration can definitely have a much bigger impact than SON by itself on the densification.

In 5G, we talk about 'edgeless cells', 'no-edge networks', etc. Orchestration of the network will have a big part to play in this too.

Anyway, here is the whitepaper embedded below and available to download from Slideshare

X2: The necessity for Interoperability and Interference management in HetNets

Recently I wrote an article in the TMN magazine here about HetNet co-ordination. One important point that I mentioned here (and in several of the trainings that I do) is that X2 can be quite a useful interface, especially when you want to manage Interference between just macro cells or between different types of cells, as in HetNet environment. From the TMN article:

The initial deployments of LTE did not pay too much emphasis on X2 interface being present. Inter-operability was another issue for which X2 didn’t work very well. One of the major benefits of having an X2 interface is that different base stations or eNodeB’s (hereafter referred to as just eNB’s) can talk to each other and coordinate to make sure interference is kept at the minimum, especially on the cell edges. The Macro-cell’s had the provision for the X2 interface from the beginning, which formed the basis for Inter-Cell Interference Coordination (ICIC). Initially, the Small-cell’s didn’t have a facility for an X2 interface amongst them or with the Macro-cell. The support of X2 for Small-cell’s was added in 3GPP Release-10 and 3GPP Relese-11 (hereafter referred to as just Release-10 and Release-11) as seen in the picture. X2 for Small-cell’s is crucial for Interference management in HetNets.

The Small Cell Forum just published a whitepaper called "X2 interoperability in multi-vendor X2 HetNets". This paper is quite interesting with just the right amount of details. In their own words:

A key area of standardization needed to support small cells relates to the procedures to assist co-ordination with macrocells over LTE’s ‘X2’ interface. This document surveys standards currently in place to support frequency domain interference coordination,time domain interference coordination, mobility robustness and mobility load balancing. 

The whitepaper is available to download from here and is embedded below:

Small Cell Forum Release 4: X2 Interoperability from Zahid Ghadialy

Small Cells Research Bible

Here is a detailed research on Small Cells from Mehdi Bennis and Walid Saad presented in IEEE Dyspan 2014, this month. Feel free to add any comments for questions you may have.

Recent Advances in Wireless Small Cell Networks from Zahid Ghadialy