7/29/2019 A New Small Cell Approach is Required for Large Indoor Buildings

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A new small cell approach is required for large indoor buildings

Written by David Chambers

Tuesday, 06 November 2012 18:30

Behind the hockey stick growth charts showing rapid wireless data traffic increases, there is abehavioural change taking place inside our workplaces. Voice calls previously using fixed wiredtelephone extensions are more often being taken on mobile phones. Checking email is no longerconstrained to the desktop, or even laptop. These days your email is more likely to be read on aBlackberry, smartphone or tablet as evidenced by those little "sent from my iPhone" footnotes

on the reply.

This trend is present in all sizes of business, large and small, and across both public and privatesector. Competitive advantage is to be gained by anticipating and addressing this change in user

behaviour.

Mobile operators have traditionally addressed their large enterprise customers through a directsales channel, signing deals for thousands of employees in return for low rates and subsidisedphones. This market segment can contribute as much as 30% of their total revenue. Often, thearrangement will require the operator to provide adequate coverage and capacity inside the office

building to handle the traffic demand.

In the past, large buildings would be equipped with Distributed Antenna Systems (DAS) whichdistribute the wireless signal throughout using bulky and expensive RF feeder equipment.Installations may take weeks, involve RF technical specialists and have significant costs. This

restricted these solutions to the top tier of customers and left many corporate customers less thanhappy with the service provided.

New technical architecture required

At Small Cells Global Congress 2012, Huawei stated that "DAS is simply not good enoughanymore" new technical solutions are required. Their approach is to expand a nearbymacrocell, connecting it using fibre to a distributed array of radio access nodes inside thebuilding. However, the need for a dark fibre connection between the two (at a sensible price)cannot be assumed, even in urban areas. The cost of the system is based on macrocell

technology, rather than purpose designed small cell approach.

Also speaking at the conference were SpiderCloud, who have perfected their high capacityenterprise solution which they call an Enterprise Radio Access Network (E-RAN), specifically

architected to meet the needs of large scale enterprise deployments.

A third approach evolves from residential femtocells, but using more powerful and highercapacity. Ubiquisys offer a femto-grid which allows small clusters of enterprise femtocells to co-ordinate between themselves and shift the capacity and coverage of each cell to adapt to

measured traffic demand.

7/29/2019 A New Small Cell Approach is Required for Large Indoor Buildings

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Today, NEC currently resell and deploy both SpiderCloud and Ubiquisys systems.

While the needs of SOHO businesses could be met by 1 or 2 small cells, and small to medium

businesses might require up to 10, large businesses could justify anything up to 100 or more.

Key attributes of a large enterprise small cell solution

There are a number of factors that need to be designed into a small cell enterprise solution

targeted at the larger corporate premises.

1. Seamless Mobility. A residential or small office femtocell user may leave the building onlytwo or three times a day, and is unlikely to be mid-call. Large offices, equipped with manysmall cells, frequently have people walking around mid-call or mid-session. There areseveral issues with this:

Calls/Sessions need to be seamlessly transferred between the small cells and bydefault would be handled by the core network. This places a heavy load thatcould better be handled locally.

Frequent hard handovers require additional processing and transmissions with

the mobile device, increasing battery consumption and reducing battery life. There may also be a greater risk of call drops.

2. Consistently high throughput. One issue with DAS systems is that they distributed a fixedamount of capacity around the building improving coverage but not necessarilycapacity. Each extra small cell provides substantial extra throughput, essential to meetthe growing demand and avoid wide variations in data rates.

3. Enterprise-Centred Management. An operator should be able to manage each enterprisesmall cell system as a single entity, rather than having to manage individual small cells.This reduces operational costs and allows the operator to offer and report on SLAs(Service Level Agreements) to its enterprise customers.

4. Rapid deployment. The cost of an enterprise installation impact both parties businessescan't afford periods of long or disruptive downtime, while the operator needs the cost tobe low to remain viable and competitive. The system should be smart enough not torequire specialist technical planning or deployment staff, use commonly availablewiring/cabling, and be self-organising and self-optimising to adapt to each individualcorporate environment.

5. Efficient use of Backhaul. Dedicated transmission between the customer site and theoperator's core network can be costly, but is likely to be justified to ensure good QoS.Optimising the traffic on this link by reducing unnecessary signalling overhead, routingcalls and intranet traffic locally within the building improves system efficiency, securityand reduces cost. A by-product is the reduced transaction load on the core network.

6. Scalability. A solution needs to be able to cope with the largest enterprise buildings andcampuses of anything up to 500,000 square feet. It also needs to handle the forecastgrowth in higher traffic demand either by subsequent addition of extra small cells and/oruse of Wi-Fi and/or LTE within the same radio heads.