App coverage. ericsson White paper Uen Rev B August 2015

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1 ericsson White paper Uen Rev B August 2015 App coverage effectively relating network performance to user experience Mobile broadband networks, smart devices and apps bring significant benefits for people, business and society. However, operators looking to grasp opportunities in this ecosystem face a number of challenges to driving growth and staying competitive. App coverage provides an integrated approach to these challenges by allowing operators to relate network performance to user experience and to manage it effectively.

2 Evolving demands raise user expectations Over the past decade, mobile service usage has evolved from predominantly voice to a variety of apps on a multitude of smart devices. These apps support new ways of innovating, collaborating and socializing in the Networked Society, and drive users expectations of mobile broadband services. Ultimately, for every operator and for other stakeholders that are part of the mobile broadband ecosystem, success depends on the quality of the user experience. This influences everything from brand reputation and subscriber loyalty, to the ability to generate a sufficient return on investment. Operators using the Net Promoter Score (NPS) to monitor subscriber loyalty have consistently found that network performance is the leading factor determining a customer s likelihood to recommend their mobile service to others [1]. As a user s experience of network performance is increasingly related to how their apps perform, app coverage therefore becomes a critical link between network performance and subscriber satisfaction. App coverage an indicator of user experience App coverage is the geographical area within which an app works as the user expects. As every app has its own set of requirements, it means that each app has its own coverage map [2]. App coverage can be measured as the probability that a mobile broadband network will deliver sufficient performance for a good user experience for that app. App coverage is the geographical area within which an app works as the user expects Each app has its own coverage map App coverage Evolving demands raise user expectations 2

3 The ecosystem: devices, apps, networks The significance of the overall mobile broadband ecosystem in delivering user experiences needs to be considered in the app coverage approach. This ecosystem is characterized by an everexpanding array of highly capable smart devices and powerful apps delivered over mobile broadband networks. Each of these elements has its own development cycle, and they all have to work well together to create the best possible user experience [3]. Apps Networks Devices Figure 1: The mobile broadband ecosystem. Devices Device technology is continuously advancing. New smartphones, feature phones, laptops and tablets are constantly being developed, while bigger screens, better resolution, faster processors as well as better camera and video capabilities are influencing user behavior, driving usage, and leading to higher data traffic volumes. At the same time, new adaptive mechanisms are available that allow higher resolution in content delivery [4]. Apps There are millions of apps designed for different platforms available for download from the major application stores and other marketplaces, and the number is growing constantly. All of these apps place a variety of demands on the network that need to be taken into consideration. Mobile broadband networks Mobile broadband networks are evolving with higher speeds and improved functionality. As an example, WCDMA/HSPA 900MHz deployments are today considered mainstream. To give another example, LTE performance has been further enhanced by carrier aggregation functionality. In the coming years, there will be continued evolutionary steps toward improved downlink and uplink speeds and improvements in network and terminal capabilities. Low-band networks can complement higher frequency deployments, as they improve coverage, QoS and QoE. Providing a good user experience will always involve a balancing act between these continuously evolving networks, devices and apps. In other words, the elements of the ecosystem are interdependent, and it takes time for one element to be upgraded and use the capabilities of the other elements, although this cycle is shortening. App coverage The ecosystem: devices, apps, networks 3

4 Different apps, different demands Popular apps with different network needs constantly come and go. A successful approach to app coverage therefore involves not only understanding the requirements of the most used app types, but also anticipating the usage trends and number of new users with smart devices. This understanding allows targets to be set to deliver sufficient performance end-to-end with a high probability throughout the network coverage area. Uploading photos and video clips on social networks at events, for instance, is dependent on uplink throughput, while apps that involve streaming media, such as music and video, are predominantly dependent on downlink throughput rates. While streaming apps tend to use a variety of mechanisms to smoothen variable network performance (adaptive codecs, local caching and buffering), if downlink throughput is not high enough, time-to-content increases along with the risk of media freezing during the actual streaming process. Web browsing and social media are, besides downlink throughput, also dependent on latency caused by the way network protocols interact with system signaling. Web pages are not static documents; they are built dynamically and usually consist of many objects, which places tougher demands on the end-to-end latency of the system. Real-time apps on IP, such as voice services, and cloud based services, such as enterprise apps, also place demands on latency. Real-time collaboration services such as videoconferencing typically need symmetrical uplink and downlink throughput, and since good uplink throughput is normally more challenging to obtain, it often becomes the limiting factor. Type of app Downlink throughput Uplink throughput Latency Photo and video upload Streaming music and video Web browsing Videoconferencing Table 1: Main limiting factors on network performance for different app types. Each app has its own set of requirements and therefore has its own coverage map App coverage Different apps, different demands 4

5 Network considerations In the previous section, requirements on network performance for the different apps have been structured around throughput (both uplink and downlink) and latency. To ensure the expected performance, an end-to-end approach will have to be applied, taking all network domains into consideration: RAN, transport, core and beyond. For example, the radio part of the system will have a strong impact on the available throughput. In general, throughput depends on the achieved signal-to-interference (SIR) ratio, as well as the availability of transmission slots in the scheduler that governs the multiplexing of resources. Typically, SIR at the cell center is good, and then degrades as the user gets closer to the cell edge, due to attenuation of the desired signal and stronger interference levels from the surrounding cells. The quality of the radio frequency (RF) design (mainly signal strength, antenna settings and site density) will determine whether the throughput at the cell edge is sufficient for certain apps or services. In addition, the derivation of a sound RF design needs to account for site-to-site distance, the existence of different propagation environments, obstacles, construction materials and traffic hotspots, as well as indoor locations that may require dedicated indoor solutions, specifically for environmentally sound buildings. Moreover, the RF design will also determine the radio capacity of the system; that is to say, the amount of simultaneous users that can be served with minimum throughput across the target area. Capacity is a major issue affecting user experience, and it cannot be separated from coverage, as they are the result of a trade-off between the same network resources. Furthermore, latency is also related to the number of users among which the radio resources are shared, which depends on the RF design and the geographical traffic density. If a radio base station needs to handle too much traffic and the scheduler is excessively loaded, this might end up introducing excessive delay. Some potential actions to improve the radio domain are: power optimization, RF adjustments, deployment of indoor systems, activation of more capable software features, and the addition of new sites. Similarly, in the transport network, latency, throughput and capacity will be determined by the way in which the different links and routing entities are dimensioned, as well as by the configuration of the different QoS policies that dynamically grant priority to certain traffic flows over others. Along the same lines, in the core, the aforementioned set of parameters will be strongly influenced by the way in which the main nodes are dimensioned and configured, for example, with regard to QoS policies. Ultimately, suboptimal performance might be due to issues outside the mobile network, such as overload in the Domain Name Server, limited app server capacity or saturated links. Consequently, managing network performance in order to protect user experience demands a true end-to-end approach to designing, building and running mobile networks. This includes the performance of the radio network as well as the backhaul, packet core and content delivery networks. To ensure the expected performance, an end-to-end approach will have to be applied App coverage Network considerations 5

6 App coverage applied A fundamental question for operators should be: How can we enable the best user experience as effectively as possible for as many users as possible, while considering and adapting to the implications of the evolving ecosystem given the apps and devices in use today and in the future? Originally, mobile networks were built to deliver access to voice services across a defined coverage area. The main indicators for determining service quality are accessibility, retainability and integrity, which in the context of voice include measurements of network availability, droppedcall rates and speech quality. However, the indicators for voice quality are not applicable for data services. A new set of indicators therefore needs to be settled regarding accessibility, retainability and integrity. Delivering data services for use with many apps, on a variety of devices, requires decisions about service levels that must be continually revisited, as each app coverage map is dynamic and evolves with the ecosystem and app usage. Each app coverage map is dynamic and evolves with the ecosystem and app usage The app coverage approach enables the integration of coverage, capacity and quality into a holistic view of network performance relative to app requirements. These requirements are those set for apps to work according to users expectations. The app coverage approach enables the integration of coverage, capacity and quality into a holistic view of network performance relative to app requirements The following app coverage approach, leveraging system service KPIs (S-KPIs) and resource KPIs (R-KPIs) to ensure the relation between user experience and network performance, can be built into an operator s quality process: 1. Define user experience (S-KPIs) As a first step, it is important to understand the S-KPIs with the highest correlation with the NPS for each service/app, as well as the thresholds that need to be reached in order to ensure user satisfaction. These thresholds are typically different for each market and operator, and also evolve as time goes by. 2. Monitor user experience (S-KPIs) After defining the important S-KPIs, it is paramount to deploy a system able to monitor them. The end-to-end nature of these S-KPIs makes it typically impossible to estimate them based on traditional resource-oriented performance management platforms, and new systems are required, based on, for example, probes or terminal agents. 3. Identify improvement areas (R-KPIs/S-KPIs) When a certain S-KPI does not reach the required level for a certain area, an intelligent analysis is needed in order to find out the elements in the end-to-end chain that are causing this problem. Those individual elements (or interfaces) will typically show suboptimal performance, which can be seen by monitoring the relevant R-KPIs. The target will be to improve those R-KPIs. App coverage App coverage applied 6

7 4. Optimize After identifying elements with suboptimal performance, their corresponding R-KPIs need to be improved. First of all, there is a need to explore how to improve the systems that are currently deployed, either by troubleshooting malfunctioning elements or by tuning the different settings to make the most of the available installed base. 5. Determine investments After ensuring that the current systems are fully optimized, it is necessary to explore whether further investments are required in extra hardware, features or bandwidth. In this respect, it is fundamental to command investments exactly where and when needed. Determine investments Define user experience (S-KPIs) Optimize (R-KPIs / S-KPIs) Monitor user experience (S-KPIs) Identify improvement areas (R-KPIs) Figure 2: Improving and maintaining the quality of user experience is a continuous process. An effective way to improve app coverage is to enhance network performance; starting by optimizing and improving the existing radio infrastructure, and then densifying the macro layer and adding small cells in additional layers as a complement to the macro layer when and where it matters. Operators should therefore: > > Improve: Tune and optimize the radio network to gain maximum spectrum efficiency; upgrade system software to the latest release; review parameter settings, and deploy software features to maximize the performance of the current radio-network infrastructure; introduce low-band HSPA and/or LTE; add MIMO (multiple-input, multiple-output) and increased sectorization; modernize and increase capacity in backhaul and transport networks by using microwave and fiber solutions; and add support for more spectrum. > > Densify: Add capacity to the macro network; upgrade content and application servers; add hybrid radio configurations to reuse the existing installed base (for example, by connecting additional macro or micro radio units to existing baseband units); deploy antenna integrated radios to simplify expansion to new and existing macro sites; and expand the backhaul network to new sites. > > Add: Add integrated small cells to secure maximum performance so that all the technologies (3G, LTE and Wi-Fi) are harmonized across different network layers at indoor and outdoor locations; optimize to ensure seamless interworking between cell layers. Each small cell can be connected directly to the macro network through microwave or fiber. App coverage App coverage applied 7

8 Conclusion For every operator and for other industry stakeholders, success depends on the quality of the user experience. This influences everything from brand reputation and subscriber loyalty, to the ability to generate a sufficient return on investment. As a user s experience of network performance is directly related to how their apps perform, app coverage therefore becomes a critical link between network performance and subscriber satisfaction. App coverage can be measured as the probability that a mobile broadband network delivers sufficient performance for a good user experience for a specific app. The app coverage approach enables operators to relate evolving app requirements to network performance in order to deliver the defined user experience. To deliver the expected performance, a true end-to-end approach to designing, building and running mobile broadband networks will have to be applied. All aspects of network performance radio network throughput, latency and capacity, as well as the performance of the backhaul, packet core and content delivery networks need to be considered while identifying improvement areas. Network improvements should start with optimizing the current system before additional network investments are considered. In summary, mobile broadband networks, smart devices and apps bring significant benefits for people, business and society. However, operators looking to grasp opportunities in this ecosystem face a number of challenges to driving growth and staying competitive. App coverage provides an integrated approach to these challenges by allowing operators to relate network performance to user experience and to manage it effectively. App coverage conclusion 8

9 References [1] Ericsson ConsumerLab, Performance shapes smartphone behavior, July 2014, available at: [2] Ericsson, App coverage applied, Extract from the Ericsson Mobility Report, November 2013, available at: [3] Ericsson, Smart mobile devices and app coverage, Extract from the Ericsson Mobility Report, June 2014, available at: [4] Ericsson, Screen size matters, Extract from the Ericsson Mobility Report, June 2015, available at: App coverage references 9

10 GLOSSARY nps rf R-kpi sir S-kpi Net Promoter Score radio frequency resource KPI signal-to-interference ratio system service KPI 2015 Ericsson AB All rights reserved App coverage glossary 10