Monday, 15 January 2018

Autonomous Relaying Drones

Came across this post from Prof. David Gesbert about the project ERC PERFUME are involved in. The post says:

Autonomous Flying Cellular Relay Robots

The team of ERC Advanced PERFUME project ( at EURECOM under Prof. David Gesbert recently pioneered autonomous flying base station relays. The aerial robots  use machine learning to self-optimize their position based on suitable radio measurements and provide end-to-end enhanced connectivity to mobile users carrying off-the-shelf commercial terminals.  The communication layer builds on the OpenAirInterface developped at EURECOM's Communications Systems Department.

A first video was just unveiled here:

I have written about drones multiple times in the past (see here, here & here for example). Last week I looked at the relays (or Relay Nodes, RNs) as defined by 3GPP. We could safely assume that this autonomous relaying drone is Layer 3 Type 1a/1b RN.

I have heard multiple operators talking about this kind of approach where a person or group of people can get preferential services via drones in festivals and events. Of course it would make sense that these people are on some VIP package or emergency services workers.

Its an interesting concept but there will be many open questions. It would have to be tried for a long time to identify and iron out all the issues.

Do you agree / disagree?

Wednesday, 10 January 2018

Relays (RN) and Donor eNode Bs (DeNB)

Relays a.k.a. Relay Node (RN) in standards has been a part of the standards for a while but I don't hear about them often. The only time recently when I heard about them were with Airspan's MagicBox small cells deployed in Sprint (see news here). In fact the article speculates:

LTE UE Relay was specified within 3GPP’s Release 10. There are different types of Relay and it would seem Sprint’s will be Type 2, which sees the Relay Node (or MagicBox) retransmit on the same code as provided by its macro “donor” cell.

While I don't have any further details about it, I am not too sure about it. Type 2 relays are complex and require change in the existing eNodeB's. I should clarify here that we are talking about Layer 3 relays in this post. An earlier presentation from Airspan mentioned that they use Type 1a/1b relay architecture. See here.

The presentation below has some nice simple explanation of the Relay nodes and its workings

In case of Type 2 relays, there is a much more architecture change involved. This architecture change requires modification of the existing eNB to Donor eNB (DeNB).

Going back to 3GPP TS 36.300: E-UTRA and E-UTRAN Overall description; Stage 2 document:

The DeNB hosts the following functions in addition to the eNB functions:
- S1/X2 proxy functionality for supporting RNs;
- S11 termination and S-GW/P-GW functionality for supporting RNs.

Further on, in section 4.7

E-UTRAN supports relaying by having a Relay Node (RN) wirelessly connect to an eNB serving the RN, called Donor eNB (DeNB), via a modified version of the E-UTRA radio interface, the modified version being called the Un interface.

The RN supports the eNB functionality meaning it terminates the radio protocols of the E-UTRA radio interface, and the S1 and X2 interfaces. From a specification point of view, functionality defined for eNBs, e.g. RNL and TNL, also applies to RNs unless explicitly specified. RNs do not support NNSF.

In addition to the eNB functionality, the RN also supports a subset of the UE functionality, e.g. physical layer, layer-2, RRC, and NAS functionality, in order to wirelessly connect to the DeNB.

The RN terminates the S1, X2 and Un interfaces. The DeNB provides S1 and X2 proxy functionality between the RN and other network nodes (other eNBs, MMEs and S GWs). The S1 and X2 proxy functionality includes passing UE-dedicated S1 and X2 signalling messages as well as GTP data packets between the S1 and X2 interfaces associated with the RN and the S1 and X2 interfaces associated with other network nodes. Due to the proxy functionality, the DeNB appears as an MME (for S1-MME), an eNB (for X2) and an S-GW (for S1-U) to the RN. 

In phase II of RN operation, the DeNB also embeds and provides the S-GW/P-GW-like functions needed for the RN operation. This includes creating a session for the RN and managing EPS bearers for the RN, as well as terminating the S11 interface towards the MME serving the RN.

The RN and DeNB also perform mapping of signalling and data packets onto EPS bearers that are setup for the RN. The mapping is based on existing QoS mechanisms defined for the UE and the P-GW.

In phase II of RN operation, the P-GW functions in the DeNB allocate an IP address for the RN for the O&M which may be different than the S1 IP address of the DeNB.

Based on the complexity and additional changes required for Type 2 relays, I am not surprised that they are not very popular. If you think otherwise, do let me know.

Thanks to Dr. Kit Kilgour for providing insights into this topic.

Wednesday, 3 January 2018

How Small Cells will develop through 4.5G & 5G

Just came across this old article from Radisys (in TMN magazine), written by Renuka Bhalerao. Available on Radisys site here if you want to download.

Some points from the article:
  • Small Cells are good for LTE in unlicensed bands
  • … and LTE in unlicensed is good for small cells
  • Moving to cloud architecture is promising for the RAN – but there’s no one way to do it
  • Mobile Edge Computing and the intelligent edge requires small cells
  • We are seeing the emergence of an “IoT small cell”
  • LTE-A PRO features will tax small cell software systems

Complete article available here.

Thursday, 21 December 2017

CW Seminar on DAS vs Small Cells

I mentioned about the CW seminar in my earlier post here. The event is over so here are a few takeaways from the seminar.

The good news about CW Small Cells events is that David Chambers (ThinkSmallCell) does a very comprehensive summary. For this one, its available here.

For a limited time (for non-members), the presentations from the speakers is available on CW website here.

I wanted to highlight few takeaways and stats that were quoted during the seminar as follows:

  • The 5 challenges of deploying small cells: compelling event, capacity, complexity, coverage, cost
  • 90 operators now offer unlimited service with voice, SMS & Data
  • Due to European roaming charges having been scrapped, there is 300% growth in European roaming traffic since last year.
  • Average consumption is 1.9Gbytes/month forecast to be 15.8Gbytes by 2022. Finish operator Elisa is already running at an average of 18GB/month
  • Modern inbuilding systems are 2T2R with many older installation still using SISO.
  • 40% of the workforce will be freelancers, temps, independent contractors and solopreneurs by 2020 (Not sure if this is UK or worldwide figure)
  • 39% of millenials say they interact more with their smartphones than they do with theur significant others, parents, friends, children or co-workers
  • By the end of 2017, around 14000 co-working spaces will be in operation worldwide
  • 67% of people around the world use a personal device at work to some degree

I have highlighted Opencell's view on DAS vs Small Cells in the earlier post here. This Tweet below also shows the comparison points

Bob Slorach, from Wireless Infrastructure Group (WIG), drew some clear guidelines about building size, pointing to the needs of buildings between about 50000 to 300000 sq. ft. This represents a huge unmet demand of around 2 Billion sq. ft. in the UK alone.

As can be seen in the picture above, picocells can serve smaller venues while a 5 watt small cell (microcell) with distributed RF can satisfy the 100 - 300K sq. ft. venues. For bigger venues, a higher power unit would be required. It would also justify to have a neutral host solution so the costs could be distributed and coverage is available for everyone.

Adis Omeragic, Special Projects Manager at EE, shared his side of the story. While his slides are still not on the site (they are expected to be available), I have emnedded a tweet below.

Some of the points he made were, while passive DAS may no longer be used, active DAS will be around. Only about 5% of DAS deployments in the UK have all four operators connected as of today.

According to Adis, DAS displacement is slow because of lack of roadmap alignment between macros and small cells. Small cells upgrade path is very limited. DAS allows Carrier Aggregation, Multi-technology and multi-band capability, SON features which are more common in macros, etc.

Due to the new features like 4x4 MIMO and even Massive MIMO, things may start going in favour of small cells.

One final point that was discussed in the panel was whether VoWiFi is good enough so there is no longer a need for residential or enterprise femtocells.

While the panelists agreed that VoWifi is good enough for residential, it may not be good enough for enterprises. I disagree. If the enterprise has designed their WiFi networks properly, this may not be much of an issue.

There is other issue of the lack of devices and operators support for VoWiFi. As EE pointed out, they only support it for post-paid customers, on direct contract with them. So pre-paid, MVNO and partner customers wont benefit. Also, its supported in limited number of devices.

Sunday, 17 December 2017

Small Cells Densification for 4G & 5G

The recent Small Cell Forum (SCF) press release mentions that: SCF forecasts that between 2015 and 2025, new non-residential small cell deployments will grow at a compound annual rate of 36%, to reach almost 8.5 million, and by 2025 deployments will be 22 times higher than in 2015.

The research also provides an insight into operator’s densification plans, with 40% of operators expecting to deploy between 100 and 350 small cells per square kilometer (indoors and outdoors) in the areas they densify by 2020. Additionally, in the first 2-3 years of deploying 5G New Radio, 58% expect to focus primarily on small cells. The research also shows that the industry is already seeing acceleration of deployments in the Enterprise, where small cell deployments rose by 98% between 2015 and 2017, and are set to grow by up to 1600% from 2015 to 2025.

In addition, SCF also published Release 10 (not a permanent link though), a collection of documents, presentations and videos that present the organization’s vision for the 5G era. This collection is a response to the requirements the Forum spent the summer collating resulting from regional and partner events in India, North America and Latin America. SCF listened to input from operators, across the various geographies, on their key challenges and created a work program designed specifically to resolve the key issues raised.

I will link some SCF documents at the bottom of this post.

Stephane Daeuble, Nokia also published a blog post on this topic not long back. In that he points out:

Nokia looked at the growth in demand facing one operator in a very busy US city. In 2014, traffic density was around 1 Gbps/km2 and was served by an average 20 macrocell sites per km2.

By 2017, traffic density hit 4 Gbps/km2. The operator simply adds 40 outdoor small cells and 50 indoor small cells per km2 to the network. Deploying relatively few small cells allows the operator to meet quadrupled capacity and coverage demand, both indoors and outdoors.

Let’s project these figures forward. By 2025, the operator will need a very dense network to support a ten-fold increase in traffic density. With no scope for deploying more macrocell sites and upgrades to macrocell base stations unlikely to meet the demand, even this extreme density can be supported with the help of small cells. Now we are looking at 150 outdoor and 500 indoor small cells deployed per km2, keeping to the intial 20 macrocell sites. Over the period covered by the study, the average inter-site distance plunges from 240m to 82m – a figure impossible to achieve without small cells.

The most obvious advantage of small cells is their compact physical size. They can be deployed unobtrusively to meet city regulations, giving the network a rapid, yet low cost boost in performance. Not only do they provide much-needed extra capacity and improve indoor coverage, but small cells can aid network balancing by off-loading traffic from the surrounding macrocells. Deployments have shown that, after deploying small cells, some macrocells stay above 60% average RF usage, indicating there was substantial unserved traffic with the macros alone.

If you prefer in-depth technical papers, this IEEE paper on small cell Ultra Dense Networks (UDN) is an interesting read.

Check out my introduction to macrocells & small cells and HetNets if you are looking for a quick refresher on these topics.

Here is a list of new SCF documents on densification

SCF Release 10 Vision for Densification into 5G Era

Overall Vision and Requirements gathering
[SCF110] Vision for densification into the 5G Era: Release overview
[SCF200] Ten trends SCF has driven and vision for 2027
[SCF201] Partners’ Day: Industry alignment on densification roadmap
[SCF202] Mumbai Densification Summit: Asia Market Requirements

Technologies for Densification
[SCF014] Edge Computing made simple
[SCF197] mmWave-based 5G eMBB 5G

Standards and Interoperability
[SCF085] SCF Plugfests and long term vision
[SCF208] Private ePC PlugFest report
[SCF209] Test cases for the Private ePC PlugFest
[SCF196] TR196 Small cell updates to 3GPP SA5

[SCF203] Operational aspects of densification into the 5G Era
[SCF079] Enterprise deployment process (2017 revision)

Business Models
[SCF204] 5G Era business models and stakeholder engagement
[SCF206] Business case for small cells in healthcare

Market Status and Engagement
[SCF050] Small cells market status report December 2017
[SCF194] SCF operator survey: Deployment plans and business drivers for a dense HetNet
[SCF205] Connectivity in healthcare - an essential service

References of the form [SCFXXX] are linked to their landing page on, where they can be downloaded free of charge.

Thursday, 7 December 2017

Connecting the remote Alaskan Villages

A very nice article from the recent IEEE Spectrum Magazine here.

The $300 million telecom project will boost speeds or provide service to many areas of Alaska for the first time. TERRA was completed in October after six years of construction when engineers installed its final microwave repeater. The network uses a combination of repeater data links and fiber optics to form a giant, 5,000 kilometer ring around southwest Alaska — a sparsely populated region with few paved roads and wilderness areas larger than West Virginia.

Quoting from the magazine:

With TERRA, Kotzebue residents now pay $59.99 per month for an Internet plan with download speeds of 3 Mb/s, which is not even fast enough to stream a high-definition movie. To be able to do that, they would need to pay at least $149.99 per month for 6 Mb/s. Compare that with New York City, where residents pay an average of $55 per month for 25 Mb/s.

So was it worth $300 million to bring slightly better Internet to approximately 45,000 people in 84 rural villages spread out over an area roughly the size of Germany? For GCI, it was a strategic move. The project was completed as more customers began to watch more content online. Large clients such as hospitals and schools in rural communities also needed better access to the outside world. Partly thanks to TERRA, the company welcomed $12 million in new revenue for Internet service in the first three quarters of 2017, while losing $8 million from its cable-TV division.

Here is a video on how its done and the challenges:

Complete article here.

If you like to learn more about different backhaul types, see our short video tutorial here.

Monday, 4 December 2017

MTN: Connecting Rural & Remote Africa

The annual Telco Infra Project (TIP) Summit took place recently in California. As always, there are some great presentations that have all be shared online here.

The video of the presentation is embedded below but the two images above are the main points of discussion from this presentation. The first image shows the challenges and possible approaches to solve them. The second one highlights the important point that the traditional infrastructure costs are just too high to provide connectivity in rural and remote locations.

A slightly surprising point that the speaker, Navindran Naidoo, Executive, Network Planning & Design, MTN Group brought up was that they are still looking to rollout 3G networks. In an earlier post on 3G4G blog, I talked about how the developing nations will ditch 3G in favour of 2G & 4G so this is a bit of a surprise. Even the OpenCellular project is focusing on 2G & 4G as can be seen below.

Steve Song in his blog post here highlights some good points. He points out that not enough 4G devices have reached African markets, VoLTE has still not matured and also operators have 3G spectrum available today or they can re-farm 900MHz.

Anyway, here is the video from Navindran Naidoo, Executive, Network Planning & Design, MTN Group in TIP Summit 2017.

Thursday, 30 November 2017

Virtua Small Cell Lamppost for IoT & Telematics

Virtua are showing off their rural solar small cell that fits nicely on the lamppost. The lamppost can be taken down to deploy the small cell and can be hoisted back up. Their website says:

The objective was to engineer a more cost effective rural small cell solution that would support applications such as Telematics & IOT.
The solution benefits from a hinged levered pole solution for ease of installation and maintenance. One of the applications uses GSM/Mesh repeater with a bespoke antenna and bracket design keeping the installation simple. This GSM/Mesh repeater radio technology negates the need for immediate backhaul and accelerates the solution into live operation.
A solar powered solution means that the active radio equipment is contained in the bespoke solar housing that sits at the top of the pole. The housing benefits from a lower wind resistant design and slides centrally down the levered pole for ease of install, no external power is required thus no electrical certification is necessary.  Installation is quick and simple with no external cables other than the antenna RF cables at the top of the pole making the speed to deploy cost effective keeping the customer ahead of the competition.
I can see some power issues with 3G/4G small cells, as they are more power hungry. Also, there may be issue in countries that has small winter days and very little sunshine. Nevertheless, its interesting concept.

Interesting video of their installation:

Rural Coverage Small Cells Solution - Installation from Virtua on Vimeo.

Saturday, 25 November 2017

Defining HetNets (Heterogeneous Networks)

Recently added a video/presentation looking at 2 different definitions of Heterogeneous Networks (HetNets). Presentation with video embedded below. If you like to jump to video directly, here is the link.

Related post: