Public access small cells could carry more mobile user traffic than macros in urban hotspots

New Small Cell Forum report outlines best practices and challenges in the use of public access small cell deployments including the backhaul options, interference mitigation, hybrid subscriber services and new applications

Public access small cells could carry more mobile user traffic than macros in urban hotspots

Small cells could be used to offload a large amount of mobile user traffic in urban hotspots, according to a new whitepaper published this week (8 May 2012) by the Small Cell Forum, which outlines the opportunities and challenges facing public access 3G small cell deployments. 

The new research by the Small Cell Forum - an independent industry and operator association that supports small cell deployment worldwide - highlights the major impact the technology could have in urban hotspots with conservative models indicating they could offload the majority of mobile user traffic from the local macro network. However, the report also points out important deployment considerations including challenges such as backhaul and interference and how these can be mitigated.

The paper found that public access small cells could play a key role in providing additional mobile coverage, capacity and new services in both urban and rural areas. The Forum’s research found that even with conservative public deployments, small cells could offload the majority of subscribers in many areas thereby drastically reducing network load and improving the user experience. It found that with a ratio of one public access small cell per macrocell, 21% of users would be offloaded; this rises to 56% with four small cells and 75% with 10 small cells.

Equal access or hybrid subscriber services

A major operator deployment consideration is whether to roll out open access small cells that would allow all subscribers equal access or hybrid that prioritises some users. By choosing hybrid access operators will be able to provide a ‘gold-class’ service to certain subscribers or to organisations, such as police or first responders, who may help to cover the cost of deployment by providing small cell sites and potentially backhaul as well. 

Another important operator decision will be whether to self-deploy or allow organisations (e.g. systems integrators, tenant owners, train stations or shopping malls or local IT staff) to deploy these open access small cells themselves without mobile operator personnel. This report concludes that SON (Self OrganisingNetwork) technology will be required in both cases as networks will need to be permanently aware of their surroundings – it also notes many of these capabilities are included in the 3GPP release 10 standard.

Interference challenges

A significant value of this paper is that it highlights the full variety of interference challenges that operators need to be aware of and more importantly the report describes the recommended methods for overcoming these potential issues. These potential challenges include downlink and uplink interference as well as potential impacts from mobile connections in fast-moving vehicles quickly passing through small cells. It concludes that although these challenges are very real, they can be mitigated using measures such as inter-frequency and intra-frequency handover, active hand-in as well as by re-calibrating transmit power and scheduling, all fully described in the report.

Small cell backhaul options

The paper also outlines the full range of backhaul options for public access small cells and how they vary in terms of availability, suitability, cost and latency. It notes that in rural areas there are the fewest backhaul options, but that DSL and satellite have already been successfully employed. A more extensive paper on small cell backhaul will be published by the Small Cell Forum in the coming months.

Simon Saunders, Chairman of the Small Cell Forum, said: ‘The next major stage in small cell deployments is going to be in public spaces. The entire operator community now appreciates that small cells are the key to long term mobile network capacity increases, as well as providing a means of economically delivering coverage in rural blackspots. Their impact will be especially dramatic in dense urban hotspots where small cells could quickly be carrying more users and data capacity than the local macro network. However, this transformation in mobile networks is not without its challenges. This new paper outlines the key considerations for public access small cell deployments, as well as how these challenges can be overcome.’

New applications using public access small cells

The paper also notes a range of new applications that are possible with public access small cells by employing their fine-grained location awareness, strong coverage and low cost, high-speed data connection – including coffee shop ordering and reward programs, shopping mall VIP applications and powerful and simple museum or local points of interest guides. 

However, it also points out the challenges that could impact uptake. First, in order to encourage broad uptake of public small cell apps, the small cells will need to support subscribers from other mobile networks. Second, in order to retain high levels of user loyalty and satisfaction it will need to support opt-in functionality. Finally, operators need to consider alternative billing arrangements such as support for ‘gold subscribers’, or to allow shops hosting applications to take on the data costs rather than the consumer. 

Small cell growth predictions

The public access small cell market is set to undergo dramatic growth with Informa predicting installed units to rise from 595,000 in 2012 to 2.9 million in 2016 – a 480% (or 5x) increase. According to ABI Research, the public access market is likely to represent 64% of small cell market revenues despite comprising only 6% of shipments by 2016.

Written by Wireless magazine
Wireless magazine

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