CEM: A Powerful Tool for Analyzing Low QoE in FTTx Networks

FTTx Network Development and User Experience

FTTx networks, based on the passive optical network (PON) technology, have been developing for more than 20 years. The global FTTx penetration rate had exceeded 65% by the end of 2022. FTTx broadband has become an essential part for modern households, providing technical infrastructure for various applications such as high-speed Internet (HSI), video streaming, online education, and online office.

As network technology evolves over time, the O&M of FTTx networks has gradually changed from the previous rough mode, focusing on key performance indicators (KPIs), to a refinement and experience-oriented approaches. User experience has becoming increasingly important. More than 64% of users consider user experience the most important factor when choosing a service provider, and 48% of users are willing to change providers for a better experience according to research. In addition, the COVID-19 has spurred a heightened demand for broadband user experience improvements, raising the bar for users’ expectations of their broadband network providers.

FTTx provides users with fixed broadband services such as IPTV, video streaming, and Internet. The bandwidth and speed of FTTx networks used to be the major concerns of users. However, with the upgrading of PON technologies and continuous bandwidth acceleration, the network speed is no longer a bottleneck that limits user experience. Users have gradually become less sensitive to bandwidth increases. Instead, the focus has shifted towards service-specific quality indicators, known as key quality indicators (KQIs), which include factors like delay, jitter, response success rate, response time, connection stability, and video smoothness. To monitor, quantify, analyze, and manage the user experience, customer experience management (CEM) systems have emerged.

CEM Solution Helps to Improve User Experience

To align with operators’ shift from network performance-based O&M to user experience-based O&M, and to meet their needs for transitioning to big data operations, ZTE has launched the CEM solution for FTTx networks (Fig. 1). Positioned at the service quality and user experience layer, the CEM system can perceive the service experience of home broadband users, and provide accurate data support for analyzing low quality of experience (QoE) issues, delimiting and locating root cause, actively optimizing low QoE, and enhancing user satisfaction.

The CEM solution enables collaboration of the built-in blade in OLT with the big data analysis system to provide user experience-oriented O&M service support. A built-in blade board is inserted in PON OLT to minimize equipment room space, resolve power supply and consumption issues, and enhance the edge computing capability on OLT. The service traffic of broadband users is forwarded to the built-in blade board through the OLT. The built-in blade board identifies the specific service type of the user, extracts key service quality indicators, and calculates the segment delay to facilitate the delimitation of low QoE issues.

After identifying services and finishing the initial processing of basic indicators, the board uploads the processed data to the CEM big data analysis platform. The CEM platform makes comprehensive analysis and calculations based on the raw data and third-party system interconnection data. It gives quantitative presentation of user experience, performs low QoE identification, root cause delimitation, and generates AI user profiles. This helps operators improve user experience and implement precise marketing strategies.

CEM Enables Wider Broadband Service Identification

In the CEM solution, PON OLT needs powerful computing capabilities to support the collection, analysis, and processing of service information. An OLT built-in blade board acts as a tool for collecting broadband service data. The new-generation OLT built-in blade board uses ZTE’s self-developed CPU and network processor, occupying only one slot of PON OLT (Fig. 2). The system can identify six major categories of broadband services, including video, gaming, web browsing, email, upload/download, and instant messaging. For each service type, the system selects the KQIs that affect the service for data collection and analysis as the basis of user experience quantification. ZTE’s CEM system can identify more than 18,000 service sources. A single built-in blade board can collect, analyze, and process service traffic from multiple OLTs, serving around 10,000 users. This built-in blade not only enhances the value-added service processing capabilities of OLTs, but also ensures low energy consumption and no additional space required in the equipment room, thereby reducing operational expenses (OPEX).

Clearer Insight into Low QoE Users

Quantifying user experience has been challenging due to its subjectivity and abstraction. ZTE’s CEM solution addresses this issue by creating an intelligent user perception evaluation model that leverages a neural network algorithm based on transformer structure. It comprehensively considers data such as access network link status, home networking status, and service experience indicators. Additionally, it takes into account the temporal aspect of human experience memory by employing long short-term memory (LSTM) neural network training. This results in the generation of customer experience indicators (CEI) for quantifying user experience, providing a comprehensive reflection of user experience change trends, and actively identifying low QoE users. The system enables real-time monitoring of CEIs by areas, devices, ports, and users, and supports 7×24-hour KQI metrics and user access traceability, helping operators gain clear insights into user experience.

Faster Location of Low QoE Root Cause

ZTE’s CEM solution uses OLT built-in blade boards to move the service protocol analysis tool closer to the user side. It calculates the segment service delay in the FTTx network to provide a low QoE delimitation capability. By analyzing the delays and packet losses in the segments of the “home network – ONU – OLT – BRAS – content source” path, it can more accurately identify issues between the network segments and facilitate fault delimitation. The CEM system can interconnect with third-party systems, such as EMS, resource management system, and remote management system. It can precisely locate low QoE users and analyze the root causes based on system data, covering over 20 low QoE scenarios. According to China Mobile’s existing network deployment experience, the adoption of ZTE’s CEM solution enables China Mobile to shorten the time needed to locate the root causes of low QoE from over four hours per user to just 10 minutes, thus substantially improving its efficiency in identifying the root causes of low QoE.

As the growth rate of broadband user base slows down, operators need to explore new network operational methods. In the future, broadband operational strategies will gradually change from scale-based and bandwidth-focused operations to experience-centric management, which has become a widely accepted trend. Prioritizing user experience, delivering scenario-based SLA guarantees to a vast user base, creating deterministic broadband experiences, and securing additional premiums will be the objectives of operators. ZTE is willing to partner with operators worldwide in building high-quality experience-driven FTTx networks, assisting in their transformation.