June 14, 2019
With the advent of LTE capable smartphones the roll out of LTE is gathering pace around the world. The capabilities of LTE networks are set to revolutionize the user experience of applications such as mobile gaming and video-intensive applications. However, a customer will not be served purely by an LTE network, rather they will be served by the LTE layer of a heterogeneous network consisting of multiple technologies. Their experience will be highly influenced by the service they are delivered when they inevitably drop back to the UMTS/HSDPA layer and, in many cases, the GPRS/EDGE layer, as shown in Figure 1.
Figure 1. Poor service causing LTE customers to shift to UMTS
In the process of rolling out 4G service, a Tier 1 Mobile Operator was interested in situations where 4G devices were being inappropriately passed to the existing 3G network layer. The operator sought guidance regarding the priorities for future site deployment and identification of sub-optimal 4G infrastructure behavior. They turned to the Viavi Solutions™ ariesoGEO to provide detailed intelligence on the performance of the new 4G service and on 4G-on-3G hotspots within their network.
Achieving unprecedented performance levels
Traditional network data-driven techniques are not sufficient to address these multitechnology challenges. Understanding intertechnology handovers merely at a cell statistics level does not give any insight into the impact on user experience, or the steps
required to resolve issues. By focusing on the customer and geolocating every segment of a subscriber call or session, ariesoGEO allows the operator to understand the true customer experience across all layers and gain unprecedented insight into how the layers are interacting.
Stop drive testing
Early deployments of new technologies have traditionally relied on extensive drive testing to understand the network performance. As well as the very high cost of such testing, it does not represent real traffic. With ariesoGEO, every customer with an LTE capable device becomes a drive test team. By analyzing real calls, ariesoGEO reveals the performance on the network where it really matters without the cost of drive test teams, as Figure 2 shows.
Figure 2: Real call analysis with ariesoGEO
Growing the network for real traffic
With limited resources, operators must focus their LTE rollout to places where customers are actually using the new services. Then as data grows, they must ensure that expansion keeps pace to preserve the initial experience. Using geolocation technology that leads the industry, ariesoGEO can locate traffic hotspots across all technologies, typically down to building level. By supporting all technologies and collecting data 24/7, all customers’ traffic patterns can be identified. The advanced analytical techniques help them to understand this traffic, revealing insights, such as device mix, that are critical in making load management and offload decisions, as Figure 3 shows. Harnessing the power of this technology allows operators to deploy capital with surgical precision.
Figure 3. Traffic can be broken down by technology
Cut problem-solving time in half
By processing and storing every event of every call, ariesoGEO provides unprecedented insight into the precise root cause of problem areas of the network. Powerful analyses quickly sort the causes of bad experience to help engineers focus on the critical issues. Detailed RF KPI maps enable them to clearly understand the RF conditions, not only of the LTE layer but also the RF conditions in the other technology layers, allowing immediate understanding of the service a user will experience on both sides of an intertechnology handover. Access to this detailed information, shown in Figure 4, lets engineers to solve problems requiring multiple data collection tasks in hours rather than days, and all from a single solution.
Figure 4. Root-cause analysis – dropped connections
Automating key optimization tasks
As networks evolve, neighbor relationships must be updated daily. With a proven track record in automatic neighbor optimization in 3G networks, ariesoGEO now delivers it across technology layers. Fully automating this task frees valuable engineering resources from routine tasks so they can focus on more critical areas.
4G and 3G Interactions
Generally, 4G-capable devices can utilize 3G and even 2G network services. The intention is that such devices should use the 4G layer as far as possible, deferring to lower specification layers only when the higher layer cannot sustain the service required. While on lower layers, devices should return to the 4G layer as soon as conditions permit. The ariesoGEO solution was used to generate maps showing the density of usage that 4G devices were making on the 3G layer. The representation in Figure 5 was achieved by tracking 3G activity and filtering to include usage only from 4G-capable devices. The dots identify the operators’ sites, while sector symbols identify operational 4G infrastructure. Clearly some 4G-on-3G usage occurs in areas where the operator has yet to roll out 4G service.
There are three reasons why devices may pass from 4G down to other technologies:
1. Where users request services such as voice that are not offered by the 4G network
2. Where devices that have roamed from elsewhere cannot access to the 4G network
3. Where 4G services are unavailable or 4G connectivity cannot be sustained
Figure 5. 3G network usage by 4G-capable devices
The first two reasons have to be accepted within any network. They can be accounted for through additional filtering of the usage maps by service type and by device capability. Figure 6 shows remaining data usage that could be handled by a 4G network.
4G Deployment and Optimization
In addition to roll-out issues, ariesoGEO also revealed cases where 4G service should have been expected, yet 4G devices appeared enmasse on the 3G layer. For example, Figure 6 shows heavy usage to the south of the area close to sites that Figure 8 reveals to offer high data throughput. Analysis of events captured by ariesoGEO in these areas revealed that much of this 3G usage stemmed from a reluctance of the network to return devices to the 4G layer after use of 3G. Figure 5 shows that data connections make up only a part of the total set of 4G-on-3G connections in this area. AriesoGEO found that, following circuit-switched fallbacks (handovers to 3G to establish voice calls), subsequent data transfers were kept on the 3G layer rather than being passed back to 4G.
Figure 6. 3G network data usage by 4G – capable devices
Cross-Technology Insight
The third reason whereby 4G devices were passed down to lower layers because the device was unable to access 4G provided the source of the issues that the operator aimed to investigate. Clearly, the center and the northwest corner of Figure 6 show high 3G data usage from 4G devices in the vicinity of sites without 4G deployed. Devices in those areas may find the more distant 4G sites do not provide coverage, or the data rates available from such sites are substantially poorer than those offered by the 3G sites.
Figure 7 shows maps generated by ariesoGEO that reveal the peak data rates reported by devices connecting to the 3G layer (bottomleft) and the 4G layer (top-right). The 3G service is consistent across the map at around 5 Mbps, dropping to 1 Mbps in some places and rising to 10 Mbps in others. The 4G service, however, is less consistent with some areas reaching up to 50 Mbps and others falling to 100kbps or less. This analysis was taken a step further in ariesoGEO by generating a Delta map showing the differences between the peak rates reported by the two networks, as shown in Figure 8.
Figure 7. Peak throughput for UMTS and LTE layers
Blue areas indicate that 4G is measured to be faster than 3G, and red areas show that 3G was the faster service. As expected, 4G service is stronger near operational sites, while 3G service prevails elsewhere.
Figure 8. Delta difference in peak rates (LTE-UMTS)
Conclusion
It can be seen that through specific cases, ariesoGEO solution has effectively supported LTE operators to design, optimize, and ensure quality of experience, save time, cost and another resources.
Viavi ariesoGEO solution has been deploying in over 30 countries with over 75 operators. This is the solution which ensures quality of RAN experience, using geo-location, which be used by top operators such as AT&T, Vodafone, Telefonica… AriesoGeo solution offers cross-technology, cross-vendor, 24/7 support with superior performance.
In Vietnam, COMIT Corporation is a strategic partner of Viavi Solutions in providing telecommunication test & measurement solutions, including ariesoGeo solution. With experience, COMIT will provide consultant, designing, test & measurement, optimization services and solutions for 2G, 3G, and 4G LTE technologies for network operators.