Meadowcells (a.k.a. Rural Small Cells)

Picture Source: Wilson Street

I last remember mentioning a Meadowcell in September when we had our Cambridge Wireless event.

We have the term #MeadowCell being thrown about today at #CWSmallCell - thanks to @simon_saunders :-)
— Zahid Ghadialy (@zahidtg) September 19, 2013

and then I forgot all about it till I saw this:

What the hell is a meadowcell? We're talking about it here: http://t.co/evsEwxgz8c via @Light_Reading
— Dan Jones (@Dan_LRMobile) February 12, 2014

So, based on the discussion on Light Reading, Simon Saunders says the following:

However I've found one additional category helpful: "Meadowcell" to contrast rural public access small cells against their "metrocell" urban counterparts. And we've found certain regulators to be enthusiastic about the opportunities they bring. The electronics for 'meadowcells'  may not be so very different from their metro counterparts though issues like backhaul may be. Its a trickier more diverse market, but given government incentives I think there is scope for the market to be comparable in size to the metro market - vendors should leap on it!

In another discussion in Forum Oxford last year, Simon stated the following:

The terms aren’t interchangeable, but likewise they don’t have hard boundaries. Femtocells = typically home and small office/SoHo. Picocells = Enterprise, retal etc (mainly indoors), Metrocells = busy cities, outdoors, “Meadowcells” = rural outdoor application of metrocells.

From what we see above, the big challenge with Meadowcell is probably the backhaul. See my earlier post on Satellite backhaul for Rural Small Cells here.

IP.Access: From Startup to Volumes

We heard from Nick Johnson last month in our Cambridge Wireless event, talking about Enterprise Small cells. He gave us some very good real life deployment examples of Small cells in public and enterprise scenarios. One such slide is shown above and others can be seen from his presentation below.

IP.Access also did a webinar with ThinkSmallCell recently in which they expanded on their offering, approach and solutions. Considering that they are one of the leaders and pioneers in the Small cells arena, it may be worthwhile hearing the webinar. The video of the webinar is embedded below and the slides are available from Slideshare here.

LTE C-RAN / Fronthaul Architectures

Its been a while since I talked about C-RAN on this blog. Meanwhile on the 3G4G blog, a presentation by Orange labs have proved to be very popular. Netmanias have posted couple of slideshares on the C-RAN architecture. They are as follows:

The first one is NTT Docomo's advanced C-RAN architecture. I have posted a presentation on Slideshare as well on this topic. It can be viewed here for more details.

The next one is the Fronthaul and Backhaul architecture by SK Telecom. I have a slideshare on a similar topic by SK Telecom here. In fact a post on 3G4G blog from the iGR whitepaper here is an interesting read on this topic as well.

Small Cells and WiFi Forecast 2012 - 2018

I have been following and having some interesting discussions on a Linkedin group where the main argument is that Small Cells may never really take off as its not a good solution and doesn't make a good business case. I think that kind of discussion is best left to do on Linkedin.

ThinkSmallCell held a webinar recently inviting couple of leading experts to discuss their forecasts for Small cells. The webinar slides and videos are embedded below. Here is a quick comparison of what these independent leading experts had to show:

The main point to note above is that we will hopefully hit 1 million public access small cells probably around/after 2015. My view on why operators have been slow in deploying small cells have been mainly to do with interference management. As we know, Small cells are deployed for Coverage and Capacity and is mainly deployed in Co-channel (same carrier as Macro). If there is no or little coverage, Small cells deployment is not an issue. With higher frequencies, the reception in the houses goes down so deploying Femtocells make sense. With public access small cells, interference (especially on 3G) has to be managed. Surprisingly the practical results for co-channel public access outdoor small cells deployed for capacity purpose is not too bad but there is a no coverage area created as a result of interference at the edge of the small cell. This can cause handover issues.

In LTE-A, Interference techniques like (f)eICIC will help handle these situations so I wont be surprised if there are lots of deployments next year with this interference management capability.

The main thing to note is that WiFi will play a huge part for the connected devices of the future. Most of the small cells deployed with also have a WiFi capability so operators can use that to offload traffic from the cellular on Wi-Fi.

My understanding is that in future we will see Macro cells mainly serve high-mobility connections (including connected cars) and Small cells and WiFi will be used for low mobility and fixed access. I guess the real advantage of cellular over Wi-Fi in this low mobility scenario is that since Wi-Fi is unlicensed, there could be interference from many unpredictable sources. Licensed cellular bands dont generally have this issue.

Anyway, the presentation and video from webinar is embedded below:

Business case for Enterprise Small Cells

In our recent Cambridge Wireless SIG event where we discussed about Enterprise small cells, Simon Saunders from Real Wireless presented a business case on Enterprise small cells. David Chambers from ThinkSmallCell has also written an excellent summary that is available here.

The presentation from Real wireless is embedded below. A more detailed study from Small cell forum is available on Scf.Io here.

Enterprise Small Cells: The Business Case from Zahid Ghadialy

Quortus: Evolving architectures for Small Cells in the Enterprise

Continuing on our theme of Enterprise Small cells, here is slightly old presentation by Quortus from the Small Cell World Summit 2013

An Introduction to 'Enterprise Small Cells'

A nice presentation by David Chambers from ThinkSmallCell summarising Enterprise Small Cells from our recent Cambridge Wireless event 'Small Cells and the Enterprise'

Enterprise Small Cells from Zahid Ghadialy

Dual-connectivity, Bearer split and other Release-12 small cell enhancements

3GPP TR 36.842 has some interesting details on the small cells enhancements for Release-12. There is too much details for me to go through at the moment but there is some discussions. One of them is on the Dual connectivity and another is Bearer split. The concept of Master eNB (MeNB) and Secondary eNB (SeNB) seems to have been introduced. Here are some interesting definitions:

Bearer Split: in dual connectivity, refers to the ability to split a bearer over multiple eNBs.

Dual Connectivity:Operation where a given UE consumes radio resources provided by at least two different network points (Master and Secondary eNBs) connected with non-ideal backhaul while in RRC_CONNECTED.

Master Cell Group: the group of the serving cells associated with the MeNB.

Master eNB: in dual connectivity, the eNB which terminates at least S1-MME and therefore act as mobility anchor towards the CN.

Secondary Cell Group: the group of the serving cells associated with the SeNB.

Secondary eNB: in dual connectivity, an eNB providing additional radio resources for the UE, which is not the Master eNB.

Xn: interface between MeNB and SeNB. Since the current E-UTRAN architecture was selected as baseline in this study, Xn in this TR means X2.

There is also the concept of RRC diversity which can help mobility. as per 36.842

RRC diversity is a potential solution for improving mobility robustness. With RRC diversity, the handover related RRC signalling could additionally be transmitted from or to a potential target cell as illustrated in Figure 7.1.3-1.  RLF could in this case be prevented as long as the UE is able to maintain a connection to at least one of the cells.  This will eventually lead to a more successful handover performance (i.e. avoiding UE RRC re-establishment procedure). The RRC diversity scheme could also be applied for handovers from the macro to pico cells, between macro or between pico cells.

Finally, the security aspects for this Bearer split and dual connectivity is also being discussed. See the latest Rel-12 security update here.

Carrier Wi-Fi: Automatic handovers in the next generation Wi-Fi

Ericsson published a paper in their journal last month about how the next generation of Wi-Fi and its integration in the 3GPP core would help moving between Wi-Fi networks and the Cellular network seamlessly.

People who read the 3G4G blog regularly would know that this is done using the Access Network Discovery and Selection Function (ANDSF). For details see here.

Another post from the 3G4G blog explains the key challenges in moving between the Cellular and Wi-Fi technology. If not done properly, the QoE can be really off putting for the end user.

The Ericsson paper highlights the following as the top-three priorities for the next generation carrier Wi-Fi:

• Traffic steering 3GPP/Wi-Fi – to maintain optimal selection of an access network so quality of experience can be ensured and data throughput maintained;
• Authentication – to provide radio-access network security for both SIM- and non-SIM-based devices; and
• DPI, support for unified billing and support for seamless handover – achieved by integrating with the core infrastructure already deployed for 3GPP access.

3GPP has been working extensively in the new releases to come up with new features that would solve some of the issues and limitations that is affecting widespread deployment of carrier Wi-Fi and seamless roaming between the different technologies. Sometime back I provided the list of the features that are being released as part of different 3GPP releases, available here.

The Ericsson paper is available on Slideshare, embedded below:

More details on NTT Docomo's Xi Femtocell

Japanese operator, NTT Docomo recently published some more details about its Xi Femtocell service. The Femtocell is a dual mode LTE-WCDMA femtocell. WCDMA is mainly used as a CS Fallback option when used with LTE device. In this case if the WCDMA part stops working for some reason then depending on the macro availability, it may hand the UE back to Macro or just keep using the LTE only service.

I could not completely figure out but it also looks like the Femtocell operates in co-channel with the Macro. During the power on, SON algorithms device the codes, the power of the femtocell, etc.

The complete article is embedded below:

W-CDMA/LTE dual-mode Ultra-compact Base Station (Xi Femtocell) from Zahid Ghadialy