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Enter the cloud. The telecom industry saw heightened focus on the cloud and virtualization techniques in 2013. On the RAN side, operators are seeing the cloud enable an efficient use of network resources, while adding the baseband pooling. This helped designate 2014 as a proof-of-concept year for the cloud radio access network, with expected deployments in 2015.

 

C-RAN expands upon the growing utility of the RAN, wherein the radio frequency and physical layer/baseband are decoupled, providing more flexibility and efficiency in managing baseband functionality. Complementary to software-defined networking and network functions virtualization, C-RAN is based on open-platform and base station virtualization, enabling processing aggregation and dynamic allocation of resources from a centralized processing unit.

 

Simultaneously, it reduces the power consumption and increases the utilization rate of processing resources, making it an energy-efficient infrastructure that adapts to changing requirements. When virtual base stations are idle at night and most of the processing power is not needed, they can be selectively turned off, or be reduced to a lower power state, without affecting service.

 

Combining radio and baseband with a real-time cloud infrastructure, C-RAN architecture is a centralized, general-purpose processing solution that enables the network to respond efficiently, dynamically and on demand.

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Given the traditional RAN’s coverage restrictions and limitations of transmission and reception signal support, the benefits of deploying a C-RAN infrastructure are clear. The C-RAN, as a centralized, general purpose processing solution, enables the efficient use of network resources. Based on open-platform and base station virtualization, C-RAN provides an ideal architecture for LTE-A functionality as well as being complementary to next-generation SDN and NFV deployments. Many major mobile operators across the globe are preparing to incorporate the cloud into their existing RAN platforms. We anticipate that 2014 will move the C-RAN beyond the “cloud hype” as operators gain a competitive edge through integrating the C-RAN in their LTE-A migration.

 

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http://www.rcrwireless.com/article/20140505/opinion/reader-forum-emergence-c-ran-lte-deployments

Unlike SDN (software-defined Networking) of NFV (network functions virtualization), C-RAN might the hottest wireless acronym you've never heard of. C-RAN stands for Cloud RAN (radio access network) as well as the less catchy Centralized RAN. In either case, C-RAN leverages distributed base station architecture to enable a host of benefits, such as capex and opex savings, increased asset utilization and savings on energy.

 

C-RAN separates the radio and antenna parts from the digital baseband path and pools multiple baseband units (BBUs) in a central office, or base station hotel. These digital-only base stations are linked via fiber to remote radio heads (RRHs). Combined with NFV, baseband tasks would be accomplished through the use of general purpose processors and generic server farms, which would link via fiber to a virtual server somewhere in the cloud.

 

That could enable companies like Intel and IBM to become the suppliers for RAN infrastructure, analysts say, challenging traditional RAN vendors like Ericsson. So far, C-RAN is dominating the advanced wireless markets of Asia, where fiber is abundant and high population densities make the architecture fiscally beneficial. But proponents of the technology believe it could eventually spread around the world. Find out more in this FierceWirelessTech special report (C-RAN: Plotting next-generation wireless from inside the base station hotel).

 

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http://www.fiercewireless.com/tech/special-reports/c-ran-plotting-next-generation-wireless-inside-base-station-hotel

Over the past couple of years a new buzzword has entered network discussions. Siân Harris finds out what mobile fronthaul is, and why mobile operators are so excited about it

 

There are several approaches for delivering fibre fronthaul for C-RAN. First, there is the use of dark fibre, which can be a good option where there is already plenty of fibre available. This has benefits for speed of deployment, but network extensibility could be a challenge.

 

An alternative is to use a solution based on wavelength-division multiplexing (WDM) and optical transport network (OTN). This improves the bandwidth for transporting RF over fibre using standards such as the common public radio interface (CPRI) protocol and enables a large number of cascading RRHs on one pair of optical fibres. CPRI is a digitised RF signal that can be carried over an optical network. It supports a number of line rates from roughly 600 Mbits/s to 10 Gbits/s.

 

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‘Fronthaul is quite challenging to do. Fundamentally it’s quite simple, but the reality is that the synchronisation and low-latency requirements are really quite hard to achieve,’ observed Jon Baldry, technical marketing director for Sweden-based optical systems manufacturer Transmode. ‘Early developments in fronthaul have been in Asia, but have been almost exclusively throwing fibre at the problem rather than building an optical network. OTN multiplexing today can’t meet the synchronisation requirements to support the protocol, although there are advances coming along to address this.’

 

For Transmode, fronthaul presents an interesting opportunity. The company already had in its portfolio equipment that could be used, and has been testing it in these new applications.

‘The technology we use for fronthaul we’ve had for very many years and use for other things. It’s early days for fronthaul technology, but our equipment is tried and tested for us so it’s business as usual for us,’ he said.

This, he explained, is an advantage for scaling quickly. ‘Some fronthaul projects have the potential to be very big and there can be a risk in scaling manufacturing very quickly with totally new products.’

 

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‘At the start of 2013 not many people had heard of fronthaul; 2014 will be key for taking it forward.’

 

Markus agreed: ‘We have crossed the line of the question mark. The market that will be created with fronthaul could be enormous. To call it snowballing would be an understatement.’

 

 

Advantages of a C-RAN architecture

A C-RAN architecture, where remote radio heads (RRHs) are sited at cell towers and baseband units (BBUs) are centralised and connected via predominantly radio over fibre links, promises several benefits over traditional approaches.

One of the biggest anticipated advantages is in energy efficiency. Centralised processing enables the number of BS sites to be reduced, which brings savings on support equipment such as air conditioning.

 

Centralised processing should also help traffic to be allocated more efficiently between cells and reduce interference between RRHs. This should simplify load balancing and traffic sharing between sites because all the BBUs are in one place and, in some implementations, shared across all the RRHs using virtualisation.

 

This is a particular benefit for new LTE networks where rapid communication between BSs is an important part of the standard. Optimising the use of each BBU and use of virtualisation also lowers power consumption because at times of lower use idle virtual BSs could be selectively turned off without disrupting the service.

 

In addition to power savings, the C-RAN architecture promises other savings in both capital expenses and operating costs. Aggregating BBUs and site support equipment in a few central locations simplifies management and operation. In the C-RAN architecture the equipment located at cell sites is simpler and lighter so requires less maintenance and support and is quicker to install. 

 

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http://fibre-systems.com/feature/tackling-mobile-data-tsunami

 

Cloud RAN is about much more than centralising baseband processing in one location and using fibre to connect to remote radio heads located, say Frank Rayal and Joe Madden. Potential cost savings and performance improvements must be balanced against the requirements for increased fronthaul capacity and low latency, and there's plenty of work left to do on the technology side as well.
By Frank Rayal, Xona Partners and Joe Madden, Mobile Experts

 

The evolution of base station architecture to a split design comprising baseband processing and remote radio head (RRH) connected by a fiber optical cable heralds the advent of Cloud RAN. 

As an architecture, Cloud RAN is much more than centralising baseband processing in one location and using the fibre optical cables to connect to remote radio heads located at the cell sites. More importantly, Cloud RAN is an attempt at decoupling the hardware and software platforms of wireless base stations. Instead of dedicated hardware, operators would deploy commercial servers in data centres to run base station functions and thereby leverage the cost structure of data centres in running wireless networks. 

The strategic implications on operator-vendor relationship cannot be more profound as this vision allows operators more agility in implementing network upgrades and selecting between vendors. 

Aside from the strategic implications, there are practical and measured benefits to Cloud RAN that fundamentally centre on reducing the cost of network operations. Leaving the cost of equipment aside, there are three main areas for cost reduction: site rental expenses, energy consumption, and network operations and maintenance. These savings are balanced against the cost of the fibre optical network required to meet fronthaul (connection between baseband and RRH) capacity and latency requirements. 

After all, supporting 2.5 Gbps for a single 2x2 20 MHz LTE channel will not come cheap. Nevertheless, there are additional benefits in performance improvement to be had. With baseband processing located in a central location, LTE-Advanced techniques such as coordinated multipoint (CoMP) become feasible.

 

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We are still in the early days of Cloud RAN and much work is still required to achieve this vision. For one, commercial servers are not powerful and efficient enough to run certain base station functions. Work is ongoing to solve this problem by innovative specialists as well as established companies (Intel, for example, has been active on this front and their recent acquisition of Mindspeed provides an additional boost). 

 

A popular approach is to offload certain base station functions to a secondary processor similar in concept to the math co-processors installed on motherboards of old PCs. How to do this and what to offload is a space where baseband and silicon vendors will strive to differentiate. Other areas for development include pooling and virtualisation of baseband processing to derive greater benefits and savings from centralisation.

 

Cloud RAN has the potential to be a disruptive architecture. It has different use cases and application scenarios that almost guarantee it will be a concept to take hold in the future where the business case is amenable. It will also energise new developments to push the limits of a number of technologies as outlined above. With the evolution of LTE to incorporate greater intelligence at Layer 2 and higher layers to expand network capacity, Cloud RAN delivers on performance in a manner the traditional distributed architecture never could.

 

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http://the-mobile-network.com/news_detail.html?news=MjI2

The wireless infrastructure network is going through a critical phase of technology evolution. A slew of equipment form factors are being rolled out to meet perpetual growth in capacity demand. All these solutions are gravitating toward maximizing the potential of precious and limited spectrum resource.

 

The 3rd Generation Partnership Project (3GPP) is a collaboration among groups of telecommunications associations. Its standardization efforts are devising ways to pack more and more bits into available spectrum within the capacity constraints governed by Shannon's law, but the wireless radio network is on the move to create topologies that allow fewer users per node to extract more bandwidth from the same spectrum.

 

There are two major macro trends pushing the network expansion in completely opposite directions. The first macro trend is deployment of an underlay of tens of small cells per macro base station, initially to improve coverage and then to deliver capacity by serving a small set of users. This trend enables the radio access network to support a higher density of callers for a given area, but it also creates complexity and scale challenges in the backhaul network. The second macro trend is splitting the traditional centralized base station into a network. The radios are located remotely, and the base station chassis is made solely of baseband functions. This split into distributed base stations allows ease of scalability in terms of increasing the density of baseband processing as well as the number of connected remote radio heads to address coverage and capacity needs effectively.

 

Cloud-RAN (also referred to as C-RAN and Centralized-RAN) is a new cellular network architecture for the future mobile network infrastructure. It is a network of high-density base stations connected to a large number of distributed remote radio heads. The concept is mobilizing technologies from wired networks to pool baseband resources using virtualization technologies. This is resulting in significant changes in baseband card architecture and design. Also, every radio node within Cloud-RAN is designed to connect to any channel card. The connectivity and algorithmic functions on the radio are also changing to leverage resource sharing effectively for load balancing and network failover. The Cloud-RAN trend simplifies backhaul but adds complexity to the connectivity between the base station chassis and the multitude of remote radio heads, also referred to as the fronthaul network.

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http://www.eetimes.com/author.asp?section_id=36&doc_id=1320836

 

You can download pdf files here (Part 1, Part2)

 

 

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What's next after Super Macros and what are the technical issues to overcome?

A critical performance metric relates to efficiency of data capacity, measured in bits per second per hertz per square metre. I've been impressed by how high the traffic levels are that we can achieve using Super Macros alone, but this won't be enough for all our future needs.

We want to evolve from our Super Macro strategy into a full HetNet (Heterogeneous Network) and what I want is a single point of control of small cells integrated with Super Macros.

For this to work well, the X2 interface which co-ordinates between small and large cells will be vital. At the outset, it's important to understand what we are trying to achieve through this mechanism.

We are very likely to be sharing the same spectrum between small cells and super macros, and this will need eICIC (enhanced Inter-Cell Interference Co-ordination), or a similar mechanism, to provide coordinated scheduling across both network layers.

When we look to implement ABS (Almost Blank Subframes) patterns, we find that these don't change often – perhaps at most every five minutes and perhaps as little as only once per hour. Although subscribers move around, the traffic hotspots might not. We find we can determine where to locate small cells to capture the maximum traffic capacity, meaning we only need install a few to make a substantial difference.

Latency across the X2 interface is a critical factor. Today, we route X2 in parallel with S1 via the security gateway, which gives us latency in the region of 10-20ms. That's less than the break/make time for mobility procedures in LTE and perfectly adequate to support eICIC and many of the other centrally coordinated techniques being discussed. These optimisation techniques do require the use of time (phase) synchronisatrion between base stations, which is something we'll introduce as and when necessary.

If you look at some of the joint processing schemes being discussed today for CoMP (Co-ordinated Multi-Point), then the X2 interface requires very low latency, which would be hugely expensive. It would need dedicated dark fibre to each site or a complete wireless mesh.

This leads me to question the C-RAN (Cloud RAN) over D-RAN (Distributed RAN) approach as a capacity enhancement. It might work well where you have access to dark fibre at low cost to connect cellsites but we find that using our Super Macro strategy combined with 5 to 8 small cells and eICIC can deliver phenomenal capacity with a D-RAN.

There are further improvements that can be made, such as better optimization tools, better radios in the handsets or using MIMO in small cells. We have been pleasantly surprised at just how much capacity we have delivered already and are able to achieve by adding a small cell layer.

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http://www.thinksmallcell.com/Femtocell-Interview/thinksmallcell-interview-with-andy-sutton-principal-network-architect-at-ee-uk-on-their-future-small-cell-plans.html

 

Other articles,

What is the potential of fronthaul /C-RAN for future radio access? 

In order to reap the rewards of fronthaul for future radio access, there is a requirement for very high capacity networks with multiple GBs. This solution only works if you own the fibre and the network, which is a rare scenario in the UK. Fronthaul for future radio access has the potential to be huge, but only in those instances where the operator already owns a high capacity dedicated network to transmit multiple GBs. In the markets MLL Telecom serves in the UK, we’re not seeing this as being a viable alternative at the moment.

Cloud-RAN must adapt to be central to carriers' LTE toolbox

By Caroline Gabriel, Research Director, Maravedis-Rethink

 

Cloud-RAN is one of the most discussed topics among mobile operators as their conversations about next generation networks become more complex. We used to hear about the elements of the new network - small cells, Wi-Fi offload, super macro and so on – largely isolation, but the priority for most cellcos is to weave all these threads together and eventually create the heterogeneous network (HetNet).

Similarly Cloud-RAN – often dismissed as an architecture that is too radical for any but a few fiber-rich, cutting edge Asian cellcos – will in fact be an important tool in a complex box. It will be an important part of LTE deployments during the rest of the decade, and 40% of cellcos will adopt it for some parts of their roll-outs by 2018, according to a new report from Maravedis-Rethink, entitled 'Tearing the Network Apart: The Economics of the New RAN to 2018'.

 

However, that level of adoption will be achieved only if certain key barriers are addressed, and it will see operators changing the basic architecture, as laid out by pioneers like China Mobile and Korea Telecom, significantly. Hybrid solutions will emerge which will be less expensive and capable of being added step-by-step to existing infrastructure and sites, as well as interworking effectively with layers of small cells or Wi-Fi, a key step to real HetNet.

Although small cells will be very important to add capacity, coverage and greater network responsiveness, the macro layer remains the primary way to expand the network, and it too must be modernized to provide better total cost of ownership, cost of data delivery and overall efficiency. There are two main approaches to this. One is Cloud-RAN, in which carriers deconstruct their networks completely, virtualizing the baseband functions in base station hotels or on standard cloud servers, and leaving just low-cost, low power radio/antenna units at the cell sites (which may be increasingly small). The other is to add more intelligence to that cell site and create what the UK's leading cellco, EE, dubs the 'super macro'.

 

These approaches need not be either/or – many operators will use a mixture of both, or will converge the two into a hybrid system where super macros act as 'master cells' within a Cloud-RAN, localizing some functions like caching and supporting a large number of more basic sub-cells, which may use a distributed antenna design.

Similarly, most operators will use a combination of Cloud-RAN and small cells on the road to HetNet, even though these two are often presented as mutually exclusive (or even confused with one another). Small cells are initially being deployed, in the public access environment, to fill gaps in the 3G network, but their real disruptive effect will be felt when they form a separate layer of capacity, interworking completely with a reconstructured macro layer.

LTE-Advanced functions such as eICIC and CoMP will make such an architecture easier to roll out, addressing some of the issues of interference between layers, and cell edge performance (indeed, many believe the main motivation to invest in Cloud-RAN will be to support CoMP better). According to the Maravedis-Rethink report, cellcos will spend $3.45bn on Cloud-RAN equipment between 2013 and 2018, in order to reduce cell site costs, allocate capacity more flexibly between sites, and better enable LTE-Advanced in the macro layer.

 

The report found that carriers are preoccupied with reducing cell site equipment costs as they 'densify' their networks to meet capacity demands. That will involve investing in integrated, autonomous small cells, but also shrinking macro layer cells to an extent where traditional base station architectures become unaffordable. The low footprint radio head/antenna units that are coming to market – such as Alcatel-Lucent's lightRadio or Ericsson's AIR – indicate how the macro RAN is increasingly distributed, with several cell sites sharing a common baseband resource. C-RAN will take that further, virtualizing those baseband functions in software on standard server platforms, and supporting hundreds of sites per central resource. Operators will slash costs by leaving only ultra-low cost equipment at the cell site, eventually driving the equipment cost down below $100 by 2020.

 

However, while C-RAN economics are very tempting, but they will only be realized by investing heavily at the back end, and by harnessing standards to ensure interoperability and reduce cost. That, in turn, will create a whole new ecosystem, as carriers are set to deploy almost 2.5m cloud-connected macro layer sites from 2013 to 2018. Many of these macro sites will be equipped with extremely low cost antenna/radio units, creating a significant opportunity for vendors in the antenna and remote radio spaces, and for a reworking of the DAS idea for C-RAN. There is also considerable R&D effort going into the IT-centric back end, notably in the massive China Mobile/Intel project with various RAN partners.

 

C-RAN faces other barriers, notably the immature state of telecoms virtualization systems, and the current need for fiber to link the basebands to every radio head. Development of virtualization standards and of microwave fronthaul technologies will be critical to improve the business model and enablers like these, which usher new vendors and platforms into the RAN ecosystem, will open up opportunities for new entrants, whether start-ups or companies from the enterprise space. There may be many architectures under discussion, but one thing is clear – the RAN of 2020 will look completely different to that of 2010.

 

For more information about Maravedis-Rethink's new RAN Service report, 'Tearing the Network Apart: The Economics of the New RAN to 2018' please contact Adlane Fellah on afellah@maravedis-bwa.com.

 

You can view this article here

The report "Cloud RAN Market (Radio Access Network) - by Components (Remote Radio Units, Optical Transport Network, BBU, Processors, Servers, Test & Measurement), by Services (Integration, Network) - Worldwide Market Forecasts and Analysis (2013 - 2018)" defines and segments the Cloud RAN market into various segments with an in-depth analysis and forecasting of revenues. The report also identifies the factors driving this market, various restraints, challenges and opportunities impacting it along with the future roadmaps.

 

Browse 82 market data tables and 54 figures spread through 211 pages and in-depth TOC on "Cloud RAN Market (Radio Access Network) - by Components (Remote Radio Units, Optical Transport Network, BBU, Processors, Servers, Test & Measurement), by Services (Integration, Network) - Worldwide Market Forecasts and Analysis (2013 - 2018)"
http://www.marketsandmarkets.com/Market-Reports/cloud-radio-access-network-ran-market-1001.html 
Early buyers will receive 10% customization on reports.

 

With the swift and continuous advancements in technology, the telecommunication industry is experiencing tremendous changes. The mobile operators have initiated an eco-friendly and centralized approach, Cloud RAN, in order to deliver quality mobile services to consumers, while maintaining their own profitability. Cloud RAN offers benefits over the traditional RAN systems and is an alternative approach for data transport in mobile communication.

 

MarketsandMarkets broadly segments the Cloud RAN market by type of components used in the architecture: Remote Radio Heads (RRHs), Baseband Units (BBUs), Optical Transport Network (OTN), processors, servers and test and measurement equipment; by services being offered: network services, system integration and custom services; and by geographical regions: North America (NA), Europe (EU), Asia Pacific (APAC), Middle East and Africa (MEA) and Latin America (LA).

 

MarketsandMarkets expects the global Cloud RAN market is expected to grow from $1.71 billion in 2013 to $11.31 billion in 2018. This represents a Compound Annual Growth Rate (CAGR) of 45.9% from 2013 to 2018. MarketsandMarkets expects Asia Pacific to hold the largest market for Cloud RAN, in terms of geographical territories and over the next five years, it is expected to experience the highest spending in the Cloud RAN space.

SAN JOSE, Calif.— Three service providers are working on plans to deploy cloud radio access networks (C-RANs), a new approach to building cellular networks. The radical concept uses banks of x86 servers to connect cellular calls rather than traditional wireless base stations.

 

China Mobile, the world's largest carrier with 700 million subscribers, has been spearheading trials and plans to deploy systems as early as 2015. Japan's NTT Docomo said it will follow in 2016, and a third unnamed carrier is now preparing plans for C-RANs, said Gilad Garon, chief executive of Asocs Ltd. which sells silicon cores for modems.

 

"In last few months any doubts whether C-RAN would happen have gone away," said Garon, whose company was chosen in February to supply baseband technology for China Mobile's trials, in an interview. "Korea Telecom is involved, and we see interest in Europe primarily from Deutsche Telekom."

 

China Mobile aims to lower the cost of C-RANs to less than $30 per LTE sector, down from about $10,000 two years ago. It will start a second round of trials later this year using servers equipped with PCI Express cards to handle baseband processing. Each card will pack four FPGAs using Asocs cores, each FPGA capable of handling 12 LTE sectors, said Garon.

 

The trial also will test Asocs' MPL, a programming language for baseband chips. MPL lets developers call C-language libraries that will run jobs on ARM, Mips or x86 processors.

 

The next trial will use only Intel servers, but emerging low power ARM servers could be used in C-RANs in the future. "There's still the cost of optics, software and servers, but the sheer DSP processing will be cheap," said Garon.

 

C-RANs will likely take their place beside traditional base stations and emerging small-cell base stations as another tool for building cellular nets, said Gordon Mansfield, chairman of the Small Cell Forum and executive director of small cell solutions and radio access network delivery at AT&T Mobility.

 

"C-RANs' biggest challenge is backhaul," said Mansfield. "It requires extreme low latency and that requires fiber" which is expensive and not widely deployed in many parts of the world where traditional and small cells will be a better fit, he said.

 

With the exception of Intel, C-RANs also lack the support of the major chip makers, Mansfield, said. "Having general purpose hardware and software is the ultimate goal, and all the big, heavy-processing silicon providers will end up there I believe, but right now it's too early to see who will come out as leaders," he added.

 

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http://www.eetimes.com/document.asp?doc_id=1318782