Network Management procedures and tools have been steadily evolving the last 20 years, in order to provide a clearer view of the managed devices and networks, help the network owner/operator take decisions for network expansion and reduce the network maintenance costs while at the same time increase network and service availability.
Network Management Solution Types
Network Management solutions have been segmented to match the specific requirements of the respective target market.
Network Management solutions for enterprises have evolved to become low-cost, commercial-off-the-shelf solutions that manage a wide variety of devices with no integration, providing a basic set of management functions, typically including performance graphs and basic trap recording as alarms.
Network Management solutions for mobile operators have evolved to incorporate advanced configuration and monitoring functions due to the importance of the Radio Access Networks and their respective backhaul networks.
Finally, another segment is focusing on integrated, unified, umbrella management for all Service Providers that manages complex networks from a single monitoring solution thus simplifying the integration effort and operational complexity of multiple Element and Network Managers.
Are these solutions so different? What do we expect to happen in the future?
The NMS market/technology segment that faces the biggest challenges is NMS for mobile operators. The importance of mobile devices and telephony is driving the mobile operators to invest heavily in their infrastructure in order to satisfy the incredible demand for capacity. As a consequence, the network architecture is under transformation and Network Management is facing a paradigm shift.
Evolution of NMS solutions for Mobile Operators
Network Management for mobile operators has seen tremendous development in both technical and commercial (market size) point of view, due to the record breaking growth and importance of mobile devices and telephony. And things are about to change once again. In fact, mobile broadband demand is growing at a tremendous rate mainly due to the popularity of smart phones and tablets, and the explosion of data hungry applications for smart devices from the likes of Apple and Google stores.
Actually, data capacity demand is expected to be increased over the next five years in a rate that is impossible to be covered by technology advancements in radio access networks. For example, most researches from the likes of TMForum and Tolaga Research, just to name a few, indicate a 20 to 30-fold increase in capacity demand, while advanced radio access technologies such as LTE and even new spectrum resources will not achieve more than 4-times capacity improvement.
This gap, this problem, cries for a solution. And the solution must come by thinking out-of-the-box. If we cannot increase capacity in the network with the technologies we use, what else can we do?
The answer to the network capacity problem is to use other technologies to offload the excess capacity demand.
Wi-Fi is a technology that when combined with other solutions such as Metro-cells, Micro-cells, Pico-cells and Femto-cells will be able to handle this increased capacity demand. But what are all these technologies, and what is required from the existing NMS for Mobile Operators to manage them?
New technologies must be managed
All these new solutions have something in common; they provide coverage to a smaller range when compared with the traditional technologies employed by Mobile Operators but they differ in their usage. That is why we need to use new terminology to help us identify these different network architectures; we name:
- Macro cells, the existing solutions that offer coverage in a relatively range area but with limited capacity,
- Small cells (SmC), the solutions that provide bigger capacity to a smaller coverage range, including outdoor metro and micro-cells for hotspots, indoor pico-cells for enterprise capacity and coverage and indoor femto or home-cells for residential capacity and coverage.
- Wi-Fi Access Points, the solutions that provide traffic offload via public or private networks.
In this new network architecture, Macro Cells will provide umbrella coverage, small cells will provide indoor and outdoor capacity extension and Wi-Fi will provide traffic offload.
But, the introduction of new technologies will have an effect on the Network Management solutions currently employed for both the Radio Access and the Backhaul. As networks become heterogeneous (i.e. hetnets), the Mobile Operators/Service Providers are forced to transform their legacy network design and management philosophies in order to enable automation and real-time network optimization. This real-time network optimization will allow on demand distribution and routing of traffic between the macro, small cells, and Wi-Fi access points of the mobile network.
But how can you implement this and what is the impact on network management?
Self Organized Networks (SON) brings a new paradigm in Network Management
The mobile industry is working to solve the problem of efficiently managing complex network architectures, by introducing a new standard that targets to simplify the operation of the network by automating many network management functions with the Self Organize Networks (SON) concept.
SON has been already used for the automated provisioning of existing small cells, such as enterprise pico cells and residential femto cells. These small cells are the “smaller” and simpler ones in terms of management, as they do not introduce interference to the Macro Cells due to their relatively low power levels. The SON provisioning function of the femto and pico cells is based on the well established TR-069 standard, that was introduced by the Broadband Forum (then named DSL Forum) and is well established in the broadband market.
But SON is not only about provisioning femto and pico cells with TR-069. SON is a concept that has been standardized for the LTS and 2G/3G networks, and consists of the following parts:
SON applicability on Wireless Backhaul
SON is included in the 3GPP specifications for LTS and is also available for 2G/3G technologies. Current implementations of SON include femto and pico cells and we see gradual migration to the metro cells. Ultimately, SON will be embraced by the whole mobile ecosystem, including macro-cells, even if this means that not all SON functions are implemented in some technologies. But how about wireless backhaul?
Wireless backhaul faces a big challenge, that is directly related with the introduction of small cells. The cost structure required for small cells must be migrated also at the backhaul. Although no specification exists, backhaul vendors are considering SON functions and their proprietary implementation where applicable in wireless backhaul. Self-configuration is the area that is most important for backhaul vendors, in order to keep installation costs low and make their solutions attractive to mobile operators.
Backhaul vendors are introducing innovative small cell backhaul products in the market, that incorporate self configuration capabilities, such as:
- Automatic Inventory, which enables operators to track the status and whereabouts of small cell backhaul devices. This is important in provisioning and configuration management of backhaul devices that are typically installed by inexperienced personnel.
- Antenna automatic alignment, that minimizes site visits and disturbance at the urban environment.
- Network Planning Integration with Network Management, to fast-track complex and lengthy procedures especially for Point-to-Multi-Point configurations.
- Automatic software download, to ensure small cell backhaul devices have the proper and latest software load
- Automatic configuration download, to ensure small cell backhaul devices get their configuration via pre-planned templates and profiles.
What is SON?
SON is a specification that consists of three main parts, Self-Configuration, Self-Optimization and Self-Healing that target to simplify and automate network management.
SON is expected to further evolve as a standard to better handle provisioning, inventory, and operation of Small Cells, Wi-fi and their backhaul. The areas that SON will play a major role are:
- Manage interference between Macro and small cells
- Smart distribution of traffic across all network layers, including macro, small-cells and Wi-Fi.
- Inclusion of Wi-Fi in the unified management platforms.
- Manage a network with substantial bigger scale, due to the small cells.
- Reduce cost for deployment and optimization of networks.
- Automatic Inventory, as described above to constantly monitor status and location of cells.
- Automatic Identification, to ensure that each cell has a unique network identity.
- Automatic Software Download, to ensure devices have the latest software load.
- Automatic Configuration Download, based on identification to enable plug-and-play provisioning.
- Automatic Neighbour Coordination, which enables small cells to identify nearby cells and configure themselves in a way to enable connection handovers.
To be able to perform self-configuration, the function of automatic inventory is required. The Network Management solution enables continuous monitoring of the status of the equipment, as well as their location and environment (neighbouring cells). Once the status and location of the device is known, provisioning and configuration can be performed. Thus, self-configuration consists of:
Currently, radio engineers continually monitor radio network performance using a variety of batched reports processed by optimization algorithms to identify configuration changes that will enable performance and availability increase. These changes can be physical, such as re-alignment or tilt of antennas, or software parameter changes such as power settings and modulation profile settings. Automation of radio optimisation is not a new concept. What SON brings is improved reliability and transparency of the optimisation algorithms, in an effort to convince radio engineers to trust these automatic algorithms.
Self-Optimization algorithms that can bring important performance improvements in next-generation mobile networks that include macro, small-cells and Wi-Fi, include:
- Energy saving algorithms, that will improve (lower) the carbon footprint of the network, but may also improve the battery life of connected mobile devices.
- Enhanced Inter-cell Interference Coordination (e-CIC), that capitalise on granular radio resource partitioning to perform radio resource allocation between macro and small cells, in order to minimise interference. e-CIC requires low latency backhaul networks to work properly.
- Real-time parameter optimisation, that allows continuous monitoring of Key Performance Indicators (KPI) and network parameters fine tuning to improve network performance. For example, if inter-cell handover performance KPI is poor, this can be detected in real time to automatically perform micro-fine-tuning of handover parameters.
- Load Balancing, that allows smart distribution of traffic between small, macro-cells and Wi-Fi. In case a cell witnesses excessive load, the algorithm will carefully orchestrate traffic to metro, pico and femto-cells to maximise capacity while at the same time minimising interference.
Alarm correlation rules will play an important role, in order to:
- Identify the root cause of alarms
- Automatically trigger actions such as self tests
- Re-configure the network the handle the failure of the cell, by distributing the traffic to neighbouring cells.
- Automatically create trouble tickets and monitor the flow of corrective actions
Barriers for SON adaption in Network Management Platforms
- SON brings a radical change in the way the Network Operation Center (NOC) operates and administers the network. The established procedures and processes, typically in the form of re-active batch-type management and optimization actions, will be replaced by automation flows. NOC engineers need to be trained and embrace the new concepts, actually the paradigm shift, otherwise problems may appear. On the other hand, engineers must be able to incorporate in the SON automation engine their own best practices, therefore the optimization process must be visible and configurable.
- The introduction of SON requires the development of new advanced functions and algorithms in the Network Management platforms. Vendors have a lot of work to do, especially when thinking about multi-vendor networks. Accordingly, Service Operators will have to upgrade their network management infrastructure to incorporate SON functionality. This results to increased cost (CAPEX).
- SON is not mature. New capabilities are emerging such as better inter-cell interference coordination with e-CIC, load balancing and real time parameter optimization. These capabilities need time to mature and to become capable to work in a demanding, complex multi-vendor network environment.
Due to this lack of maturity, Mobile Operators are not really in any hurry to adopt SON at least at the macro cell or 2G and 3G ecosystem, but the need for capacity is expected to force them to experiment with SON at least for the small cell part of the network.
Only time will tell, but automation is a definite benefit and therefore it consists the single most important motive behind all the effort and cost associated with overcoming the challenge of adapting a new paradigm in the Network Management area.
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