03 Sep 2012

Network Visualization the Key for LTE Migration

Warren Dumanski, Newfield Wireless explains how network visualisation assists operators to cost-effectively deploy, manage & optimise their LTE networks

It has been standard for mobile operators to receive network performance management statistics, at the base station level, through their OEM vendors, for several years.

However, as mobile networks have developed, and become more intricate, operators have increasingly required much more granular, and geo-located, network performance data.

They need this information in order to improve service assurance, understand changing subscriber behaviour and reduce their subscriber churn.

For 3G technologies, the wireless vendor ecosystem provided a series of solutions to address this need for greater network performance information. A subset of this suite of solutions is network visualisation applications. While these tools were initially deployed to support 3G, they are now evolving to address the exacting requirements of international mobile operators deploying LTE..

LTE Deployment Decisions

The proliferation of smartphones and tablets is driving the deployment of LTE networks. Supporting these data-intensive devices is crucial for operators when deploying LTE and they must pinpoint where network capacity is best employed. Once LTE networks are operational, the operator must then decide which areas of the network need to be prioritised for these capacity infills, which can be addressed through small cells, in order to ensure a first-class subscriber experience.

Another key consideration for operators launching LTE networks is how their new network interacts with their legacy infrastructure. Through the use of network visualisation tools operators can generate a range of network performance data which allows them to make informed decisions when looking at these questions.

For example, an operator can use a mobile traffic ‘heat map’ of their 3G footprint generated by the network visualisation tool to determine where capacity offload needs to be serviced by their new LTE overlay. Using this technology allows network engineers to view an area of the mobile network in real time; and identify where capacity is stretched.

In fact, a regular view of network throughput is a typical workflow used by engineers to drill down and establish the root cause of network problems. Operators will have their LTE deployment plan at the front of their mind. But the ‘heat map’ of the 3G network generated by the network visualisation tool, provides operators with the network information to allow them to optimise an initial LTE deployment.

 Heat map indicating traffic hotspot locations in an LTE network

Network visualisation solutions provide information to ease the process, and cost, of where network optimisation needs to occur – to ensure the network is performing at a high standard. They can help to remove the haphazard, and costly, process of deploying networks based on drive tests and customer support call data.

Drive testing is a process in which a vehicle, containing mobile radio network air interface measurement equipment, is driven around a geographic area detecting, and recording, a variety of physical and virtual network performance data. However, network visualisation and optimisation tools allow subscribers to ‘effectively’ drive test the LTE network for the operator.

Information from subscribers’ voice and data sessions can also be looked at individually, or rolled into area or network-wide assessments pertaining to coverage, traffic and data throughput. This information can allow the operator to make informed decisions on where to optimise the network and ensure it is providing best-in-class service. Understanding the experience of subscribers at the critical network launch stage, where perceptions of its quality are forged. This is where network visualisation applications excel.

This technology allows operators to detect how certain devices are performing on the LTE network; letting them use that performance data to optimise the network or ensure VIP service assurance.

Use Cases for LTE Network visualisation and optimisation tools:

• Network optimisation

• Small-cell, capacity planning

• Service assurance, customer experience management

• Device analytics

• 4G-3G technology interdependency management

 Individual LTE data sessions overlaid on a traffic map

Small Cells - Maximum Benefit

LTE networks will require small cells in order to deliver the capacity required by end users in dense urban areas. While there are discussions about heterogeneous network deployments, a more common roll-out scenario for LTE by incumbent operators is to overlay LTE onto existing sites.

As such, the operator’s initial LTE footprint is a subset of their larger 2G/3G network coverage. This preliminary ‘best effort’ network is then refined by RF and performance engineers, using any, and all, tools at their disposal. In the past, operators have assessed their capacity based on performance measurements delivered on a per-carrier and per sector basis.

At one time it was airports, stadiums and metros that engineers needed to consider as crucial areas for capacity planning. However, with smartphones and tablets driving network traffic, it is much more difficult to capacity plan for a network without a specialised tool, which can reveal actual network usage and geolocated events. Network visualisation applications enable an engineer to select a sector and determine the throughput being delivered on the network over a given period.

This visibility can allow an engineer to target the use of small cells to offload capacity from stretched infrastructure. In fact, Newfield Wireless engineers, on analogous 3G networks, have observed that deploying one to three small-cells in up to 30 per cent of sectors has allowed network capacity to be doubled, and in some cases tripled, without the use of new spectrum.

While there are a number of visualisation tools in the marketplace, not many are able to provide real-time analysis or support LTE. Using a real-time network visualisation application lets engineers optimise a cell in the field and see the impact on customer experience immediately. Understanding How 3G and 4G Work Together

Voice over LTE, VoLTE

Until Voice over LTE (VoLTE) is deployed -- and initial implementations are expected later in the year -- LTE operators are only using their 4G network for data sessions. Currently, when a subscriber on an LTE network makes or receives a voice call, the network re-routes the device to the 3G network where the voice call is supported. Upon the conclusion of the voice call the device must then be switched back to the LTE network.

If a simultaneous data session remains active after the call is completed, the subscriber data session will remain on the 3G network until that session is terminated. This has an impact on the subscriber’s perception of their 4G experience; and creates excessive demand for 3G services from stranded 4G subscribers.

Network visualisation applications provide operators with the only means to better understand the performance of this critical process, known as Circuit Switched Fall Back (CSFB), and its impact on network capacity and the experience of subscribers. CSFB is expected behaviour in the 3GPP standards framework – but must be managed until VoLTE is launched to support VoIP calls over an LTE network.

Network performance engineers can also use network visualisation applications to better understand the transitional zones between 3G and 4G networks. The information that these tools provide can be used to better manage the handoff that occurs when subscribers pass between 3G and 4G cell sites.

A much more solid understanding of hand-up to 4G and hand-down to 3G, where handoffs take place and the success rate they achieve is crucial in managing networks that contain multiple cellular technologies. Network visualisation applications also enable engineers to better understand transition zones between 3G/4G networks and manage the handoffs between technologies. Operators can set threshold triggers to ensure optimal customer experience.

Seamless LTE Deployment

The proliferation of data-hungry smart devices is driving LTE adoption by operators all over the globe. LTE provides the improved spectral efficiency and end-to-end IP infrastructure required to cope with the huge increase in mobile data usage. The network information operators use to make decisions during this transition to LTE is critical. Most operators deploying LTE will have agreed KPIs that their OEM vendors must achieve prior to their acceptance of the network. But these KPIs are often assessed by the vendor’s own performance management tools. Even more problematic is that an operator will usually conduct a multi-vendor deployment – which means comparison of reports from vendor tools that only work on their specific infrastructure.

However, the wireless vendor ecosystem has provided the answer to this conundrum – network visualisation tools. These powerful tools can draw information from multi-vendor equipment in the network. The information that they provide can assist in the decision making process for selecting and building out cell sites, small-cell site selection for capacity offload and how LTE and legacy network equipment is working together. In short – network visualisation tools make the complex transition to LTE as seamless as possible, creating value, increased capacity and a much smoother subscriber experience along the way.

Page 1 of 1

About the author

Most popular articles in Cellular telecoms