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EP-4335142-B1 - CONTROLLING COMMUNICATIONS NETWORK

EP4335142B1EP 4335142 B1EP4335142 B1EP 4335142B1EP-4335142-B1

Inventors

  • HÖYKINPURO, Veijo

Dates

Publication Date
20260506
Application Date
20220411

Claims (15)

  1. A computer implemented method performed by an automation system (111) for controlling a communications network (101), the method comprising: checking whether amount of handover failures from a first cell to a second cell exceeds a first threshold, responsive to identifying that the amount of handover failures from the first cell to the second cell exceeds (301) the first threshold, setting (306) a new cell identifier code for the second cell in the communications network, characterized by preventing cell identifier code changes of the second cell for a predefined period of time after setting the new cell identifier code for the second cell
  2. A computer implemented method performed by an automation system (111) for controlling a communications network (101), the method comprising: checking whether amount of handover failures from a first cell to a second cell exceeds a first threshold, responsive to identifying that the amount of handover failures from the first cell to the second cell exceeds (301) the first threshold, selecting (304) the pair of the first cell and the second cell for analysis, checking whether the second cell is an erroneous neighbor for the first cell, responsive to finding that the second cell is an erroneous neighbor for the first cell, removing (305) the second cell from a neighbor list of the first cell, if the second cell exists in the neighbor list, and else, setting (306) the new cell identifier code for the second cell in the communications network, characterized by preventing cell identifier code changes of the second cell for a predefined period of time after setting the new cell identifier code for the second cell
  3. The method of claim 1 or 2, wherein the first threshold is defined as a percentage of failures over total number of handover attempts from the first cell to the second cell.
  4. The method of claim 3, wherein the first threshold is 1-50 %.
  5. The method of any preceding claim, wherein the first threshold is defined as an absolute number of handover failures from the first cell to the second cell.
  6. The method of claim 5, wherein the first threshold is 40-80 failures in 4 days or 7-20 failures per day.
  7. The method of any preceding claim, wherein the first threshold is defined as a combination of a percentage of failures over total number of handover attempts from the first cell to the second cell and an absolute number of handover failures from the first cell to the second cell.
  8. The method of any preceding claim, wherein exceeding the first threshold further requires that amount of handover attempts from the first cell to the second cell exceeds a second threshold.
  9. The method of claim 8, wherein the second threshold is 40-80 handover attempts in 4 days or 7-20 handover attempts per day.
  10. The method of any preceding claim, wherein exceeding the first threshold further requires that the first threshold is exceeded at least in two consecutive days.
  11. The method of any preceding claim, wherein exceeding the first threshold further requires that amount of connection re-establishments and/or amount of connection drops in the first cell exceeds a third threshold.
  12. The method of any preceding claim, wherein the cell identifier code is Scrambling Code, SC, of 3G; or Physical Cell Identifier, PCI, of 4G or 5G.
  13. The method of any one of claims 2-12, wherein finding that the second cell is an erroneous neighbor for the first cell requires that number of same frequency cells that use the same frequency with the second cell between the first cell and the second cell exceeds a fourth threshold, wherein the fourth threshold is 60-90% of the number of available unique cell identifiers or 300-1000.
  14. An apparatus (20, 111, 112) suited for operating as an automation system comprising a processor (21), and a memory (22) including computer program code; the memory and the computer program code configured to, with the processor, cause the apparatus to perform the method of any one of claims 1-13.
  15. A computer program comprising computer executable program code (23) which when executed by a processor causes an apparatus of claim 14 to perform the method of any one of claims 1-13.

Description

TECHNICAL FIELD The present application generally relates to controlling a communications network. BACKGROUND This section illustrates useful background information without admission of any technique described herein representative of the state of the art. Cellular communications networks comprise a plurality of cells serving users of the network. There are various factors that affect operation of individual cells and cooperation between the cells. In order for the communications network to operate as intended and to provide planned quality of service, cells of the communications network need to operate as planned. Known solutions related to controlling the communications networks have been presented in WO 2009/022974 A1, WO 2016/154604 A1, US 2013/0337794 A1, and WO 2015/038230 A1. Now a new approach is taken to controlling a communications network. SUMMARY The appended claims define the scope of protection. Any examples and technical descriptions of apparatuses, products and/or methods in the description and/or drawings not covered by the claims are presented not as embodiments of the invention but as background art or examples useful for understanding the invention. Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well. BRIEF DESCRIPTION OF THE FIGURES Some example embodiments will be described with reference to the accompanying figures, in which: Fig. 1schematically shows an example scenario according to an example embodiment;Fig. 2shows a block diagram of an apparatus according to an example embodiment;Fig. 3shows a flow diagram illustrating example methods according to certain embodiments; andFig. 4illustrates an example case. DETAILED DESCRIPTION Example embodiments of the present invention and its potential advantages are understood by referring to Figs. 1 through 4 of the drawings. In the following description, like reference signs denote like elements or steps. Cells of a communication network are allocated a cell identifier code. In 3G networks, the cell identifier code is Scrambling Code, SC, and in 4G or 5G networks, the cell identifier code is Physical Cell Identifier, PCI. The number of unique cell identifier codes is limited and therefore each cell cannot be allocated their own code. Instead, the codes need to be reused. For example in 4G LTE there are 504 PCIs, in 5G NR there are 1008 PCIs, and in 3G there are 512 SCs. Since the cell identifier codes are reused, the allocation of the cell identifier codes is an important network design parameter. Non-optimal allocation of the cell identifier codes may cause problems. Problems may occur for example, if a first cell has a defined neighbor with certain frequency - cell identifier code pair, but at the same time sufficiently strong signals may be received also from a different cell that uses the same frequency - cell identifier code pair. In such case, the first cell may attempt to handover connections to the cell in the neighbor list based on the signals received from the different cell, and such handover is likely to fail as the handover decision is not based on signals received from the cell in the neighbor list. The problems with the cell identifier codes may occur for example in areas where there are many cells close to each other, so that it is not possible to allocate unique code to all cells in the area; where the same cell identifier codes are allocated to cells that are too close to each other; where there are plenty of waterways that may cause that cells are serving unpredictably far; that are near state border and signals from frequency - cell identifier code pair of other country's network reach the area. The embodiments of the invention provide new methods for controlling communication networks by adjusting cell identifier codes of cells of the communication network based on analysis of handover failures. Fig. 1 schematically shows an example scenario according to an embodiment. The scenario shows a communications network 101 comprising a plurality of cells and base stations and other network devices, and an operations support system, OSS, 102 configured to manage operations of the communications network 101. Further, the scenario shows an automation system 111. The automation system 111 is configured to implement automated controlling of operation of the communications network 101. The automation system 111 is operable to interact with the OSS 102 for example to receive performance data from the OSS 102. The automation system 111 is configured to implement at least some example embodiments of present disclosure. In an example embodiment, the scenario of Fig. 1 operates as follow