Wireless Backhaul and Vendor Landscape

As mentioned earlier, backhaul is one of the biggest challenges for Small Cells Deployment. A recent article in Maravedis Rethink stated the following:

While some people forecast that as many as 80 or 90% of outdoor metrocells will be connected by wireless backhaul, Maravedis-Rethink believes we'll see something closer to today's split in macrocells - about 55% wireless and 45% fiber. Operators will use fiber wherever possible and install short range wireless in the gaps.

In some countries, the availability of fiber is far higher than in others, for example in South Korea, China and Japan. Even in the US, where there is plenty of copper, my guess is that operators will try to reuse existing copper lines to reach the nearest fibre point of presence. As an analyst, it would be quite easy to be aggressive with high wireless backhaul forecasts, but we have to consider that in reality most operators are very conservative about adopting new technology.

So wireless backhaul may be more important for metrocells than for macrocells, but not excessively so.The most important issue for a metrocell is to offload traffic from the macro network. Location is fundamental – the NGMN (Next Generation Mobile Network) Alliance has indicated that cells need to be located within 10 meters of each traffic hotspot – so there really needs to be far more flexibility in backhaul. This is where wireless backhaul becomes more significant.

The role that third party players offering ‘small cells as a service’ such as Virgin and Colt can play is also important. The value of street furniture will increase in the coming years. Those who deployed city Wi-Fi in the past (and failed through lack of monetization) have now realised they were getting access to valuable infrastructure. If you get permission for public Wi-Fi and small cell deployment then that could make the service provider Wi-Fi business more interesting. This gives intermediate players like Virgin, who can deal directly with building, real estate and council owners, an important role to isolate network operators from many/multiple negotiations with location owners. This would make it much more convenient for operators to contract through intermediate players than directly themselves. 

Which wireless technology will be most important?

The issue here is less about technology and more about spectrum. In my opinion, the key requirements are the flexibility to deploy without having to wait for regulatory permission or having to deal with interference from other operators. Taking this into account, the main spectrum choices for mobile operators for small cells are between:

a) Availability of block allocated point to multi-point (PMP) spectrum. These are microwave frequencies, licensed exclusively in a given geographical area. For example, in Europe 26 or 28GHz or even 42GHz. 42GHz is interesting because it can use a smaller antenna and there is more spectrum available.

One reason why PMP spectrum is more interesting for metrocells than for macro is that the cells will be positioned at low heights 3-6m above street level. Streets become canyons with good RF isolation between different parallel streets. This leads to much greater spectrum reuse than has been possible before in macro, ultimately allowing the P-MP spectrum to be used more like point-to-point (P-P) because it avoids interference.

Some of the intermediate players may acquire spectrum in these bands. This will be the first place to look for small cell deployment.

b) V-Band (60GHz) is the perfect complement, especially for those who don't own block allocated spectrum. There is plenty of capacity and minimal interference. Spectrum is lightly licensed (effectively free) and the wavelength provides a benefit of small size antennas. This technology perfectly fits small cell backhaul requirements.

By contrast, the E-Band (70/80GHz) requires a larger antenna to meet the regulator requirements of the radiation mask. The larger form factor cannot be quite so easily hidden and integrated into street furniture. Some advances in size reduction are being achieved though, such as E-Band Communications' E-Link Mini.

c) Non-Line-Of-Sight (NLoS). The main challenge here is availability of spectrum, which must be below 6GHz. Some vendors in the industry such as Fastback Networks are promising high capacity also in NLoS conditions, where throughput has traditionally decreased considerably compared to LoS. If capacity is insufficient, then operators can't ensure the quality of experience. So I will be very interested to see what real-world performance these new vendors can achieve and learn how they have surmounted the capacity constraints in sub-6GHz spectrum. Advanced antenna techniques are certainly among the main tools to achieve this.

Complete article is available here.

ThinkSmallCell has compiled an excellent list of Small Cells Wireless Backhaul Vendors here. The list differentiates between different wireless technologies based on the spectrum and which vendors offer solutions for that band.

More than 5 Million Metrocells to be shipped in 2017

From the Microwave Journal:

Mobile Experts has released a new Small Cell Market Forecast, predicting more than 5 million metrocells shipped in 2017.

Based on weak shipment data during 2012, Mobile Experts predicts slow growth for residential femtocells, at only 12 percent per year. Faster growth will come from capacity upgrades, as mobile operators are pushing hard for high-capacity small cells. The new Mobile Experts forecast predicts that, taken together, outdoor metrocells and indoor capacity nodes will overtake residential femtocell shipments in the 2016 time frame.

"The Asia-Pacific market has led the way in small cells, with more than 100,000 public small cells already deployed in Korea and Japan," explained Joe Madden, Principal Analyst at Mobile Experts. "The Asian market is stretching the femtocell into areas where the small cells are handling capacity effectively for operators like KT, SKT, and NTT DoCoMo. Many other operators around the world will follow this example, as the LTE macro roll-out is completed and capacity tightens up in North America, China, Latin America, Europe, and the Middle East. The bottom line is that small cells are 65 percent less expensive than macro base stations, for adding mobile capacity."

This forecast identifies eight different types of small cells, by architecture and by power level. In this year's analysis, Mobile Experts included low-power Remote Radio Head units, multi-band small cells, and Carrier Aggregation into the forecast, with 33 band combinations identified for inter-band CA. The report breaks down small cell shipments by frequency band and identified 38 frequency bands for small cell deployment.

Complete article can be accessed here.

I have to admit that this is a very optimistic forecast on the number of Metrocells. An earlier post that listed the forecasts from Informa suggested that the number of Metrocells deployed by 2016 would be around 681,000.

The Small Cells Analyst Forecast that I posted on the 3G4G blog, did list a similar forecast from Mobile experts though. The picture above lists the differentiation in Small Cells as viewed by Mobile experts and has been obtained from here.

UK 'Not-spot' gets five Metrocells from Vodafone

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From Salisbury Journal:

LAST year, the village of Cranborne was selected as one of 12 communities UK-wide that would participate in a Vodafone pilot project to bring mobile telephone signal to rural “not-spot” areas.

Having successfully fulfilled the technical criteria for the trial, which included having no 2G or 3G signal and a sufficiently fast fixed-line broadband connection to support Vodafone’s new Open Femtocell technology, Vodafone engineers visited local businesses and community buildings in the centre of Cranborne to position five Metro Cells, each the size of a home broadband router, to give the best signal cover to the village.

The only cost to the trial community is the cost of power to each box.

In February the system was successfully installed and, earlier this month, the village celebrated the official launch of the technology.

North Dorset MP Robert Walter attended the launch. He said: “I am thrilled the new technology has been successfully installed and that, for the first time, businesses, residents and visitors can make and receive mobile telephone calls from the heart of the village. It is my sincere wish that the experience of these trials helps to deliver more solutions to rural areas affected by signal blackouts.

A good example of how Metrocells can solve coverage problem and may also future proof against capacity issues.

Are we going to see more of Cloud RAN (C-RAN) in future?

China Mobile was in news a few times the last month with regards to Metrocells and C-RAN. The first item from TelecomAsia:

Alcatel-Lucent has unveiled a new TD-LTE metro base station for its lightRadio product line that will be deployed by China Mobile, which co-developed it.

 

The compact lightRadio Metro Radio – revealed at this year’s Mobile World Congress in Barcelona – houses two lightRadio cubes, fully integrated with a directional antenna, with an output of 5W.

 

Alcatel-Lucent says the design allows it to “provide the coverage normally associated with a much bulkier, heavier remote radio unit linked to an external antenna via an RF coaxial cable.”

 

China Mobile will deploy the 2.6 GHz Metro Radio in its TD-LTE network in Shanghai, Nanjing and Qingdao – specifically, in busy indoor and outdoor locations like shopping centers where macro coverage can suffer either from building density or too many people trying to access the network.

 

The Metro Radio is the first product to result from a co-creation agreement signed by Alcatel-Lucent and China Mobile just over a year ago to conduct joint development and test activities on lightRadio TD-LTE projects.

An article on the same topic in Rethink-wireless throws a bit more light:

The TDD lightRadio Metro Radio houses two of ALU's now-famous 'cubes' (highly compact radios which can be installed on lamp posts) integrated with a directional antenna. This enables a level of coverage which would normally require a far larger remote radio unit linked to an external antenna via cable, claimed ALU.

China Mobile's first trial TD-LTE network using the lightRadio product covers 13 cities including Shanghai, Nanjing and Qingdao. The base station will be deployed in busy indoor and outdoor locations, such as retail malls and sports stadia. As well as C-RAN, Mobile also plans to deploy compact metrocells combining 3G, 4G and Wi-Fi on a massive scale in future.

Another one:

ASOCS Ltd., a Silicon IP provider of software defined radio solutions and CMRI, Research Institute of China Mobile (CMCC) Ltd., the world's largest mobile operator, have signed a strategic memorandum of understanding for the joint development, commercialization, testing and deployment of large-scale baseband processing units for China Mobile's next generation Cloud-RAN network.

Earlier trials undertaken by leading mobile operators, identified the bottleneck of Centralized Base-band Units, consisting of general purpose CPU, to perform major baseband calculations in cost and power efficient management. The solution was to introduce significant offloading capabilities of such calculations with highly specialized Modem Processing Units (MPU).

Today there is a growing understanding in the industry that such MPU should support a wide range of system partitioning, topologies and real time system performance, including large scale Collaborative Multi-point communications (COMP) and massive MIMO. Since communication algorithms are evolving over time, and since the C-RAN concept provisions on-the-fly reconfiguration of the BBU to support a variety of mobile communication standards, an MPU solution which is re-configurable at runtime has a great advantage over traditional hard-wired designs.

China Mobile (CMCC) has been pushing the cloud agenda for a long time. A whitepaper from them on the same topic is available here.

Picture source: NTT Docomo press release

NTT Docomo is another operator who believes very much in C-RAN. Occasionally it refers to the C-RAN as Centralized RAN. There were couple of announcements from their side:

The first one was a press release from Docomo here:

NTT DOCOMO, INC., Japan’s leading mobile operator and provider of integrated services centered on mobility, announced today it will begin developing high-capacity base stations built with advanced C-RAN architecture for DOCOMO’s coming next-generation LTE-Advanced (LTE-A) mobile system. The new architecture will enable quick, efficient deployment of base stations, especially in high-traffic areas such as train stations and large commercial facilities, for significantly improved data capacity and throughput.

Advanced C-RAN architecture, a brand new concept proposed by DOCOMO, will enable small “add-on” cells for localized coverage to cooperate with macro cells that provide wider area coverage. This will be achieved with carrier aggregation technology, one of the main LTE-Advanced technologies standardized by the Third Generation Partnership Project (3GPP). The small add-on cells will significantly increase throughput and system capacity while maintaining mobility performance provided by the macro cell.

High-capacity base stations utilizing advanced C-RAN architecture will serve as master base stations both for multiple macro cells covering broad areas and for add-on cells in smaller, high-traffic areas. The base stations will accommodate up to 48 macro and add-on cells at launch and even more later. Carrier aggregation will be supported for cells served by the same base station, enabling the flexible deployment of add-on cells. In addition, maximum downlink throughput will be extendible to 3Gbps, as specified by 3GPP standards.

Another one from Rethink-wireless here:

Japan's Docomo has selected the vendors, Nokia Siemens and Panasonic, which will upgrade its network with certain LTE-A features like carrier aggregation.

This is a good win for NSN, which has not featured as heavily as Ericsson and Alcatel-Lucent in the most advanced LTE roll-outs to date. Breaking into the Japanese carriers is tough, since Docomo in particular tends to rely on trusted local suppliers with which it has long-standing development alliances.

Panasonic, of course, falls into that category - it has worked with the operator since 2007 on LTE network infrastructure, but NSN was also brought into that project at an early stage and its efforts have borne fruit. The European vendor will supply its Liquid Radio multiple standard RAN. Like Docomo's LTE network, there will be heavy use of remote radio heads, with baseband processing virtualized in the cloud, as well as increasing roll-out of small cells to increase indoor and outdoor capacity. NSN says the base stations will deliver capacity of 300Mbps.

In future, the two vendors will support Docomo's own particular definition of Cloud-RAN, a concept which is being pioneered in China, Japan and South Korea, and which takes the idea of remote radio heads and shared basebands to a new level. Docomo says it favors C-RAN because the cell site equipment, consisting of radio and antenna, is compact and low power, and so can be deployed quickly in high traffic areas like train stations. It calls its architecture Advanced C-RAN and this will rely on some HetNet principles, including a separate layer of 'add-on' small cells adding localized capacity while cooperating with macrocells.

In the C-RAN, there will be high capacity master base stations supporting multiple macrocells plus the local small cells. The master BTSs will handle up to 48 macro and small cells at launch and more later. Carrier aggregation will be supported for cells served by the same base station. The carrier says it will boost peak downlink speed to 3Gbps over time, hitting 'true 4G' and 3GPP LTE-B standards.

If you are wondering what 'LTE-B' or the 'true 4G' is, see this post here.

In South Korea, both KT and SK Telecom have announced C-RAN strategies for their LTE deployments, dubbed Cloud Communications Center (CCC) and Smart Cloud Access Network (SCAN) respectively. As early as June 2011, SKT had deployed 1,772 RRHs and 609 baseband units within its LTE network in capital Seoul. The lower amount of baseband units suggests an average of almost three RRHs per baseband unit, assuming each RRH is single sector.

The above two pictures are from the Small Cells Standardization presentation here.

An old article from Rethink-wireless mentions the following:

This is the central concept of C-RAN, deconstructing the traditional base station to leave a low power unit at the cell site, integrating antenna and radio, while centralizing all the baseband activity and supporting hundreds or thousands of sites flexibly from the cloud. KT calls its LTE approach its Cloud Communications Center (CCC) architecture, and it has been co-developed with Samsung and Intel. The latter is leaping on the opportunity to bring its expertise in servers and data centers to the telco network, and in this case its platforms are integrated with Samsung modems to create a centralized exchange for signals communications processing. This is linked by fiber (essential for C-RAN) to the cell sites.

As seen in vendor strategies like ALU's lightRadio and Nokia Siemens' Liquid Radio, the CCC also harnesses virtualization technology so that the central processing resources can be allocated flexibly according to the peaks and troughs of demand in different sites. Yung Kim, senior EVP head of strategy planning at KT, told TelecomAsia: "For example, at a sports stadium you can dynamically allocate more resources for that area during a game on a millisecond basis." The design also improves coverage at the cell edge, he added, claiming twice the capacity per cell, on average, because of better improved edge management.

The CCC architecture can manage 144 base stations per server and accommodate 1,000 servers in each data center, all them acting as a central processing entity. Most tasks are run on off-the-shelf processors rather than dedicated ASICs, also a key trend to reduce the cost of data networks and to converge the norms of the IT data center with those of telecoms. The performance and power advantages of modern computer processors are now up to the task of massive telecoms networks, believe carriers like KT, hence the intense interest of Intel, although some ARM-based chip vendors like Marvell and Freescale are also pushing from the network into the data center.

Do you have an opinion on the C-RAN architectures in the future? If yes, we would like to hear.

Would Millimeter Waves be preferred Metrocell backhaul option?

Backhaul was probably the most talked about subject in our Masterclass last month and in the Cambridge Wireless Small Cells SIG event, the month before. I have also recently attended a few webinars in the last couple of months that have been talking about backhaul issues ad options. Having said that in a recent post a survey of operators showed that backhaul is the biggest challenge for Small cell deployment. There are also couple of other interesting posts on the backhaul here and here.

As can be seen in the picture above (from our Masterclass), the Millimeter wave starts from around 30GHz.

A recent article in ElectronicDesign mentioned the following:

Millimeter waves occupy the frequency spectrum from 30 GHz to 300 GHz. They’re found in the spectrum between microwaves (1 GHz to 30 GHz) and infrared (IR) waves, which is sometimes known as extremely high frequency (EHF). The wavelength (λ) is in the 1-mm to 10-mm range. At one time this part of the spectrum was essentially unused simply because few if any electronic components could generate or receive millimeter waves.

All that has changed in the past decade or so. Millimeter waves are now practical and affordable, and they’re finding all sorts of new uses. Best of all, they take the pressure off the lower frequencies and truly expand wireless communications into the outer limits of radio technology (see the table). If we go any higher in frequency, we will be using light. 

Millimeter waves open up more spectrum. Today, the spectrum from dc through microwave (30 GHz) is just about used up. Government agencies worldwide have allocated all of the “good” spectrum. There are spectrum shortages and conflicts. The expansion of cellular services with 4G technologies like LTE depends on the availability of the right sort of spectrum. The problem is that there isn’t enough of it to go around.

As a result, spectrum is like prime real estate—it’s expensive. And the expression “location, location, location” is apt for spectrum. Millimeter waves partially solve the problem by providing more room for expansion. You can take all of the useful spectrum we now use from dc to 30 GHz and drop it into the lower end of the millimeter-wave region and still have 240 GHz left over.

You can read the complete article here that gives lot more details.

Bluwan has an interesting marketing video on the same subject, embedded below:

Small Cell Forum has recently released a whitepaper on Backhaul technologies for Small Cells, available here.

The biggest challenge to Small Cells deployment

Last year when I spoke in the Small Cells Global congress, I listed the small cells deployment challenges as follows:

This list was based on the operator Mindshare session a day earlier.



Small cells deployment is gathering pace and this can be seen being reflected in the recent survey that Light Reading conducted with 103 operators during Mobile World Congress 2013.

The question relevant to Small Cells is as follows:



Its good to see that the operators are concerned about integration with Wi-Fi and Interference challenges.

Complete details of the survey can be found here.

Is 2013 the year of Metrocells?

A recent market market report by Informa for the Small Cell Forum has highlighted the following:

• December last year marked the first launch of a dual mode 3G/LTE femtocell by NTT DoCoMo which allows CS fallback and will be used to promote the migration from 3G to LTE. Orange France has also launched consumer femtocells, diversifying its small cell offerings.
• The small-cell market is growing at a rapid pace: The largest deployments have already reached 1 million active cells. Initial metrocell deployments are taking place while all the operators in several markets now offer femtocells.
• Both SKT and KT have launched LTE small cells for public access in South Korea.
• According to Informa Telecoms & Media’s estimates, the small cell market will generate US$22 billion during 2016, 73% of which will be driven by public area small cells.
• The number of small cells deployed overtook the total number of macrocells between October and November 2012 and consumer femtocells overtook macrocells during February 2013.
• The femtocell market now includes several deployments that reach well into hundreds of thousand units, including Vodafone, Softbank and SFR. Sprint’s deployment reached 1 million units as of October 2012 and analysts estimate that AT&T’s deployment has reached similar numbers.
• As of February 2013, there are 46 commercial services and a total of 60 deployment commitments.

According to this report: The Small Cell Forum released these numbers here at the Mobile World Congress. Gordon Mansfield, chairman of the Small Cell Forum, said 2013 is the "year of public access" small cells, noting that by 2016 public access small cells will drive $16.2 billion in revenue despite the fact that they only make up 4 percent of small cells today.  Mansfield also said 98 percent of mobile operators believe small cells are essential; however, of the 46 operators that have deployed small cells, the majority are larger operators.

The Informa report does provide a definition of the type of Small Cells but clearly mentions that these are for guidance only. I have posted my views earlier about what Metrocells are here and here. I much prefer to use the term 'Indoor Metrocells' rather than Picocells as Picocells are associated with legacy networks without an intelligence (SON, etc.) of its own. The same is true in outdoor case as I prefer 'Outdoor Metrocells' rather than Microcells. Having said that Microcells are still available from vendors and are comparatively more expensive but provide capability to cover larger areas and more simultaneous number of users.

The Small Cell Forum has also embarked on a Release plan to help speed up operator deployments. 'Release One' was released in the Mobile World Congress 2013 with focus on Home, the future releases with focus on Enterprise and Metrocells. An Infographic on releases is available here.

Below are some of the announcements regarding Metrocells from the last couple of weeks:

• Russia Is Bringing High-Speed Fiber to All Its Towns and will also provide cellular coverage in those towns using Metrocells. See here and here.
• ALU and China Mobile unveil TD-LTE lightRadio. The TDD lightRadio Metro Radio houses two of ALU's now-famous 'cubes' (highly compact radios which can be installed on lamp posts) integrated with a directional antenna. This enables a level of coverage which would normally require a far larger remote radio unit linked to an external antenna via cable. Details here.
• Node-H supports Broadcom’s Dual-Mode Small Cell SoC Family. Details here.
• Giza Systems and Bluwan Partner to Accelerate Middle East Heterogeneous Network Rollouts. Details here.
• CEVA and Mindspeed Extend Relationship to Address LTE-Advanced Small Cells. Details here.
• Aricent and Mindspeed Raise the Bar — Announce Launch of a High-Performing 20MHz Small Cell Reference Solution. Details here.
• Jin-Magic and Ubiquisys Join Forces to Improve Small Cell Performance. Details here.

David Chambers from ThinkSmallCell has written an excellent report rounding up Small Cells from the MWC which is available here.

Finally, there is one last chance to come to out Metrocell Masterclass in Cambridge on the 21st of March. Details here.