Is Wi-Fi the third RAN?

Most Metrocells trials that happened in the UK in 2012 and a few planned this year used Wi-Fi as the access technology. In the 3G4G blog I posted real life pictures from the Telefonica deployment. These small cells were using Wi-Fi as the access technology. The service providers are using WiFi for 'lamp/land grab' with the expectation that some of the sites would be replaced by LTE/HSPA Metrocells.

While some of these sites may start using the cellular technology, some of them will remain WiFi only. Also, the ones that use Cellular technology may still provide WiFi as an access technology, using Multimode Metrocells. We have to agree that Wi-Fi does solve the problem of Capacity crunch and when more users offload onto the WiFi, it can help improve coverage.

With Carrier Wi-Fi being touted as the next big thing, would it live up to the expectations and the hype?

Ruckus wireless have couple o interesting blog posts on this topic and I would advice anyone who is interested in this area to read them. They are available here and here. They also have an excellent whitepaper on Hotspot 2.0 that is available to view and download here.

What does the industry need from Metrocell Backhaul solutions?

An article by Justin Paul:

The original small cells, femtocells for residential and enterprise customers, used standard broadband internet for their backhaul connections into the mobile network core. Metrocells, deployed by operators for widespread public use in streets and densely populated urban areas, typically don't have this option. This has led to a range of innovative new wireless products both from established and upcoming vendors.

The Industry has already made its views known

In June 2012 the Next Generation Mobile Network Alliance (NGNM), an organisation of leading mobile communications companies, published a white paper outlining the requirements for small cell backhaul. The paper, written jointly by contributors from EE, Alcatel-Lucent, Huawei and others, provides an excellent overview of the topic.

"The raison d'etre of backhaul is to provide connectivity between the small cells and core nodes with the desired QoS level".

Using existing macrocell sites to consolidate backhaul for small cells

Most operators have pre-existing backhaul solutions that serve their macro cellular sites, even if in some cases that backhaul capacity is no longer adequate for the huge quantities of data required by smartphone users. These operators need to factor in the needs of their new small cells with the capabilities of their existing macro cells to ensure simple and cost-effective backhaul solutions.

In Dec 2012 EE revealed that they were in the process of upgrading every aggregation hub in their new LTE network from 1Gigabit/s to 10Gigabit/s as standard to cope with expected capacity demands.

There are also likely to be a few new "Small Cell Greenfield Operators" who will look to roll-out networks and provide backhaul with no existing legacy network, which presents a whole new set of challenges. These operators will start with a clean sheet and be able to use the most cost-effective solutions, but will suffer from the lack of a macrocellular base sites where backhaul can be aggregated.

Complete article: What does the industry need from Metrocell Backhaul solutions? | Metrocells | Small Cells:

We recently also held a Metrocells Masterclass at the IET in London where Justin Paul took us through the complete backhaul needs and options. The picture above is from his slide deck. The next one workshop is on the 21st of March in Cambridge. More details at: http://bit.ly/Metrocell  

EE: Sharing experiences from small cell backhaul trials

Here is the complete presentation by EE as requested by quite a few people.

EE: Sharing experiences from small cell backhaul trials from Zahid Ghadialy

What is a Metrocell? - definition by Alcatel-Lucent

Looking through an old ALU whitepaper, I found another way of describing Metrocell, so here it is:

Metro cells, the latest evolution in small cells, are based on the same low cost femtocell technology that has been successfully used in home and enterprise cells, but with enhanced capacity and coverage. With higher processing and transmit power, the first generation of metro cells is engineered to serve from 16 to 32 users and provide a coverage range from less than 100 meters in dense urban locations to several hundred meters in rural environments. However, unlike home and enterprise cells, metro cells are owned and managed by a MSP and typically used in public or open access areas to augment the capacity or coverage of a larger macro network.

Available in both indoor and outdoor versions, metro cells are plug-and-play devices that use Self-Organizing Network (SON) technology to automate network configuration and optimization, significantly reducing network planning, deployment and maintenance costs. While indoor versions use an existing broadband connection to backhaul traffic to a core network, outdoor versions may be opportunistically deployed to take advantage of existing wireline or wireless sites and backhaul infrastructure, such as Fiber-to-the-Node (FTTN), Fiber-to-the-Home (FTTH), Very-high-speed Digital Subscriber Line (VDSL) street cabinets, and DSL backbone.

Since metro cells use licensed spectrum and are part of the MSP’s larger mobility network, they provide the same trusted security and quality of service (QoS) as the macro network. With seamless handovers, users can roam from metro cells to the macro network and vice versa. Metro cells also deliver the same services as the macro network (for example, voice, Short Message Service (SMS), and multimedia services), and support application programming interfaces (APIs), that may be used for developing new, innovative services. In short, metro cells promise to be the ideal small cells for network offloading.

Original post: 3G and 4G Wireless Blog: Macrocells or Metrocells?:

There is one final chance to register for our Metrocells Masterclass in London on the 21st of Feb. Details here.

Infonetics: In-building, outdoor small cells to handle quarter of mobile traffic by 2016 - FierceMobileIT

By 2016, telecom operators expect in-building and outdoor small cells, such as microcells, picocells, and public access femtocells, to handle around one-quarter of mobile traffic, according to the latest research from Infonetics Research. 

A full 86 percent of the operators surveyed by Infonetics plan to backhaul small cell traffic to nearby macrocell sites using a variety of locations, including buildings, streetlights, and traffic and utility poles 

Operators will deploy various forms of microwave technology, such as non-line-of-sight, standard microwave and millimeter wave, although fiber is their preferred backhaul technology.

More info here: Infonetics: In-building, outdoor small cells to handle quarter of mobile traffic by 2016 - FierceMobileIT:

Small Cell Backhaul options: Wired and Wireless

Another couple of slides from Andy Sutton's presentation. This time focussing on the backhaul

Related posts on the same topic:

• Small Cell Business Cases: What does the industry need from Metrocell Backhaul solutions? - Think Small Cell
• Nice Picture summarising 'Wireless Backhaul' Options - 3G4G Blog
• Small Cell Backhaul Solution Types - 3G4G Blog

Where to Deploy Metrocells - Infographic by Alcatel Lucent

Where to Deploy Metrocells - Infographic by Alcatel Lucent from Zahid Ghadialy

Small Cells on the Lamp posts and other street furniture

A lot of discussions, especially in the UK are focussed on lamp posts and other street furniture that will be used to host the outdoor Small cells or Metrocells. Some new players / operators are using the opportunity for land grab as its being called.

In a recent discussion Andy Sutton, Principal Network Architect, Network Strategy, Architecture & Design, EE discussed some of the problems that are faced with the so called lamp posts deployment. An example given was that of Birmingham in UK. See below:

As can be seen, only in this one city there are 7 different types of lamp posts. Each of them requires a different type of Small cell, different planning permission, different risk assessments, etc. For each type there is a need to check how sturdy the pole is, how will the backhaul be provided, are there enough power points that can cater for the small cell and other electrical furniture (eg microwave backhaul, or electronic sign, Christmas lights, etc.). There is also a need for metering so that the electricity can be charged separately.

Edinburgh, Scotland for example does not have enough lamp-posts for Small cell deployments, so there is a need for alternative strategy. In Belfast, Northern Ireland, the lamp posts are controlled by one central switch. When they are switched off there is no power to the pole.

I am not even going to discuss about the planning issues as there are too many and needs its own dedicated post. My post from the Small Cells Global congress last year list some more issues. My favourite being that in the US, Small Cells should be in bullet proof casing due to too many guns being around.

Metrocell Q&A: Dedicated or Shared carrier?

From Alcatel-Lucent techzine:

SHOULD I USE DEDICATED OR SHARED CARRIER?

While both dedicated and shared carrier solutions can be built, a selective dedicated carrier is always preferred over shared carrier for metro cell deployments, especially in outdoor environments where macro cell signal levels will be higher (Figure 6):

• With dedicated carrier, the MNO reserves a carrier for the exclusive use of metro cells in geographies that have been specifically targeted as needing extra capacity. In all other areas this same carrier may be used by macro cells. The use of a dedicated carrier avoids interference with the macro cell, which enables metro cells to cover wider areas and to absorb a larger amount of traffic off the macro network – greatly improving the TCO.
• With shared carrier deployments, metro cells use one of the same carriers assigned to the macro layer, which would normally have one or more additional dedicated carriers. The coverage range and offload effectiveness of metro cells deployed with shared carrier are lower than those using dedicated carriers. Additionally, metro cells cannot be placed too close to high-power macro cells with this type of deployment, as represented by the red exclusion zone in Figure 6.

Figure 6. A dedicated carrier is preferred over a shared carrier

TURNING ANSWERS INTO STRATEGY

Each MNO’s metro cell deployment strategy should be based on their W-CDMA spectrum holdings and LTE launch timing (Table 2).

Table 2. Metro cells deployment strategies depend on W-CDMA spectrum and LTE plans

Spectrum-rich W-CDMA MNO launching LTE early (2011 – 2013)

MNOs with rich W-CDMA spectrum holdings and launching LTE early should deploy W-CDMA metro cells to both indoor locations and traffic hotspots using a dedicated carrier, while also deploying LTE metro cells to traffic hotspots. To help offload the macro network in hotspots, the MNO may also consider deploying Wi-Fi-integrated metro cells.

Spectrum-rich W-CDMA MNO launching LTE late (2013 – 2015)

Operators with rich W-CDMA spectrum holdings, but launching LTE late, should also deploy W-CDMA metro cells to both indoor locations and traffic hotspots, using shared carrier. To help manage interference and avoid handoffs, traffic should also be segmented, so only HSPA data traffic is offloaded to the metro cells in hotspots. These MNOs will also benefit from deploying Wi-Fi access points that are integrated with the metro cells to help further offload the macro network.

Spectrum-poor W-CDMA MNO launching LTE early (2011 – 2013)

MNOs with poor W-CDMA spectrum holdings and launching LTE early should deploy W-CDMA metro cells in shared carrier to indoor locations only, while also deploying LTE metro cells to traffic hotspots for extra capacity. If the MNO has a Wi-Fi access network, these sites can easily be used for the deployment of metro cells by simply swapping out the legacy Wi-Fi access points for Wi-Fi-integrated metro cells.

MSM: Multi Standard Metrocell

Interesting way of AT&T keeping the small cells differentiation simple. We generally classify them in some more types as can be seen from the Metrocells taster presentation below:

I encourage everyone working in this field to attend our workshop if possible to discuss these and much more. Link http://bit.ly/Metrocell

Non-Line-of-Sight Wireless Backhaul for LTE Picocell/Metrocell Deployments

Let’s Get Real! Non-Line-of-Sight Wireless Backhaul for LTE Picocell Deployments from Zahid Ghadialy