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Always Set to Receive: Configuration Management for Small Cells in Mobile Networks

Network Services

Underground parking, elevators, re- inforced concrete – they all are strong enemies of mobile radio reception. The introduction of Femto-, Pico- and Micro Cells provides efficient support to resolve this problem and fill the co-verage gap in critical areas. In this context, the Femto cells are of particu-lar significance. The challenge for the providers is to integrate them into their networks.

Dropped calls belong to the major nuisances when talking on the phone outdoors while you are on the move, and with each new generation of smartphones equipped with more and more features, the tolerance towards the problems in telephony and data reception is dwindling: even if we got used to short battery lives of mobile phones, gaps in coverage are dama-ging the reputation of mobile service providers. It is not without reason that the annual network test has gained such importance so that the results are not only published in the trade papers, but also in the public media on a regular basis. The provision of addi-tional small radio cells, so-called Small Cells, offers key advantages to both user and provider.

Small Cells is an umbrella term for special "small" mobile radio cells with short range, usually from a few meters to several hundred. For comparison, the range of macro cells is several kilo-metres. Consequently, the trans- mission power and radio range of Small Cells is low. However, in terms of

radio technology they are based on the same principle as standard mobile cells (macro cells), and so they are also fully integrated into the mobile radio network of a network operator. Therefore, Small Cells should form integral part of the network operator's planning and operation process.

The connection to the provider's network (Mobile Backhaul) is usually made over the internet at any place granting you access. Hence, expensive leased lines are not necessary. This allows mobile service providers to ea-sily expand their networks, especially in above-mentioned indoor zones or other hard to reach places for radio technology. Thereby, providers are able to fill the gaps of mobile radio and coverage at reasonable cost and effort.

Focus of interest: Femto Cells and Pico CellsEven in areas with adequate radio coverage the transport capacity in the public provider network can be reduced by using Small Cells, because

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the data is transported to a small extent only via the network elements of the mobile service provider. Com- pared to ordinary base stations, the mobile service providers save additio-nal high costs accruing from network connections, location and network operation.

Based on the range and area of use (indoors / outdoors) there are three types of Small Cells: Micro Cells, Pico Cells and Femto Cells.

� Metro Cells or Micro Cells: Range approx. 500 meters up to 2 kilometers; transmit power approx. 2W up to 10W

� Pico Cells: Range 50 meters up to 500 meters; 200mW-2W

� Femto Cells: Range up to 50 meters; transmit power 20mW to 200mW

In particular, the "smaller" Femto Cells and Pico Cells, which are mainly used indoors due to their short range, are relevant for companies and home users because they can precisely fill any gaps. A major advantage for the mobile service provider is the fact that the radio frequencies on which these cells are transmitting the signals are not subject to any obligation of coordi-nation with the German Regulatory Authority. There is only one restric-tion: it must be guaranteed that the cells support the emergency call func-tion and the location tracking of the mobile phone used.

To achieve a smooth interaction with the "regular" radio network, a radio technology based integration into the provider network is required. This means that the communication and/or connection transfer, the so-called

handover from a macro cell to a Femto Cell and vice versa must be transpa-rent to the mobile phone user. As a result, network planners should care-fully plan and integrate Femto Cells in their network planning and network operation processes.

To ensure a speedy supply of Femto Cells to end users, a comprehensive and automated network provisioning is the basic requirement. This solution links all planning and operating systems involved and finally is respon-sible for the product's success with the provider. By integrating Femto Cells into the Common Planning & Configuration Manager (CPCM), MicroNova has excelled in closing the gap between planning and provisio-ning systems. The use of CPCM allows a consistent reconciliation of "Femto Planning Data" with the planning and

Core Network

Serving GPRSSupport Node MSC Server

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Node BImage 1: The Femto Cell is connected to the core network via the internet

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operating data of the macro network. Femto Provisioning with CPCMFrom a CPCM perspective, the process starts with the customer order and the communication of the provisioning data to the CPCM via WebService; the data includes the IDs and the so-called IMSI list (International Mobile Sub-scriber Identity) to unmistakably identify network subscribers. CPCM then automatically assigns a network element name and forwards the cell information to the Radio Planning Tool (RPT). The system continues to generate the cell in the RPT. If this task is completed successfully, the feed-back message consisting of Cell ID, location area code and location coordi-nates including emergency routing information is sent to CPCM. Thus, the Femto planning data necessary for the planning process can be managed in

CPM in the usual, tried, and tested manner and checked for consistency.

The CPM plug-in "Access Routing Zone Manager" (ARM) automatically creates cells with the associated routing information for the emergency service numbers in the Mobile Switching Server (MSS) of the provider's core network, the Mobile Core. At the same time, CPCM provides all necessary cell-specific information including Cell ID, location area code, location coordi-nates for the billing management in the billing system. After the cell is successfully set up in the Mobile Core, CPCM communicates the cell to the provisioning system of the Femto Cell manufacturer. Moreover, status information feedback of active Femto Cells in the provider network of CPM allows the network planner to request status monitoring and reporting.

Conclusion: Evidence of FlexibilityAs on numerous occasions before, MicroNova has shown the importance of a flexible configuration and management system for mobile radio networks by designing the CPCM. On the one hand, end users benefit from the services, on the other hand, providers benefit from customer satisfaction. The integration of Femto Cells into CPCM once again demonst-rates the flexibility and expandability of the solution provided by MicroNova and emphasizes the benefits for mobile service providers.

Image 2: Parameters and ranges of operation for the different cell types

Ingo.Bauer@micronova.de

www.micronova.de/netzmanagement/loesungen/cpcm

Dipl.-Inf. (Univ.) Ingo Bauer

Network Services

Indoor: 10-100mWOutdoor: 0.2-1WCell radius: several 10 meters

Indoor: 20-100mWOutdoor: 0.2-1WCell radius: several 10 meters

Indoor: 100-250mWOutdoor: 1-5WCell radius: several 10 meters

Outdoor: 5-10WCell radius: several 100 meters

Outdoor: >10WCell radius: several kilometers

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