JP5908021B2 - Neighbor cell self-configuration and optimization in wireless telecommunication networks - Google Patents

Description

  The present invention relates to self-configuration and optimization of neighboring cells in a wireless telecommunications network.

  FIG. 1 of the accompanying drawings shows a wireless telecommunication network. Here, many communication cells (A, B, C, D) are defined by this wireless telecommunication network, and the radio base station 2 provides services to each of them. Each communication cell covers a geographical range, and a wide range can be covered by combining many cells. The illustrated mobile terminal 4 is communicating in the cell A and can move around the system 1.

  The base station 2 includes a number of receiving units and transmitting units, and provides a radio coverage area to one or more cells. Each base station 2 is connected to a network “backbone”, ie, a core network infrastructure (not shown), thereby enabling communication between the base station and other networks. In the system example of FIG. 1, one base station is shown for each cell.

  An important concept in such a network is a cell and its neighboring cells. During a call, it is typical for the mobile terminal 4 to move around between cells, moving repeatedly from one cell to one of its neighboring cells. For both the network 1 and the mobile terminal 4, a list of known neighbor cells, a so-called “neighbor cell set”, is important in order to make handover between cells reliable. . The network 1 can store information on neighboring cell sets for each mobile terminal. When the mobile terminal crosses the cell boundary using the adjacent cell set, the mobile terminal is evaluated and handed over from one cell to another cell. It will be readily appreciated that the cell boundaries are not well defined but are actually somewhat blurred and the base station ranges will overlap each other.

  In the existing system, the mobile terminal 4 detects and measures cell operating parameters for neighboring cells by receiving signals from the surroundings. The measured operating parameter is typically a physical layer identifier, such as a scramble code, signal strength, signal quality, and timing information that are not uniquely assigned to a cell. The mobile terminal measures the operating parameter of each neighboring cell and reports it to the network 1. If it is determined that the quality of a neighboring cell is better than the current serving cell, the network performs a handover from the serving cell to the selected neighboring cell. Thus, the neighboring cell becomes a cell serving the mobile terminal.

  Typically, in a WCDMA (wideband code division multiple access) system, a common pilot channel (CPICH) from neighboring cells is used to determine id (scramble code) and timing information. The mobile terminal detects (Pilot Channel) transmission.

  When a mobile reports neighbor cell signal quality measurements to the network, the identity of each cell becomes important. At present, the cell identity (scramble code) is reused in a plurality of cells. Reusing identities means that cells in service may have the same identity information as neighboring cells, so the cells may become indistinguishable from each other.

  Since the physical layer identifier of a cell is not uniquely determined, the introduction and maintenance of neighboring cell sets cannot be fully automated. To resolve the conflict that there are multiple neighboring cells that use the same non-unique identifier as the serving cell, it is necessary to work manually.

  The present invention aims to reduce the cost of designing and maintaining neighboring cell sets. Based on the additional steps of the mobile terminal performing additional work, requesting to uniquely identify neighboring cells in the wireless network, and having the identity reported from the mobile terminal to the network. Embodiments of the present invention are intended to reduce human hand intervention. The method can be implemented as part of the operation support system and the base station, or can be implemented only in the RBS. This method is effective for wireless telecommunication technologies such as GSM®, WCDMA®, LTE.

1 illustrates a cellular wireless telecommunications network. A mobile terminal and a base station are shown. Fig. 4 illustrates steps of a method implementing an aspect of the present invention. Fig. 4 illustrates steps of a method implementing an aspect of the present invention. Fig. 4 illustrates steps of a method implementing an aspect of the present invention. Fig. 4 illustrates steps of a method implementing an aspect of the present invention.

  In contrast to the shortcomings of previous solutions, the present invention provides a method and architecture for maintaining a set of neighboring cells in a mobile cellular network.

  FIG. 2 is a schematic diagram showing the mobile terminal 4 and the base station 2 that communicate via the air interface 6. The base station 2 includes a control unit 22, an input / output (I / O) interface 24, a wireless transmission / reception unit 26, and an antenna 28. The control unit communicates with the mobile terminal through the air interface 6 via the transmission / reception unit 26 and the antenna 28. The controller 22 also communicates with other telecommunication networks via the I / O interface 24.

  The mobile terminal 4 includes a control unit 42, a man-machine interface (MMI) 44, a wireless transmission / reception unit 46, and an antenna 48. The control unit of the mobile terminal 4 serves to control communication with the base station 2 via the transmission / reception unit 46 that communicates with the air interface 6 and the antenna 48. Communication with the user of the apparatus is performed using a man-machine interface 44. Examples of the man-machine interface 44 include a keypad, a microphone, a loudspeaker, and a display device. The mobile terminal may be a communication device that has only a machine-to-machine interface. Such aspects of the base station and mobile terminal are designed to operate according to conventional usage.

  However, the base station 2 and the mobile terminal 4 operating according to the present invention are adapted to execute the method of the present invention described below with reference to FIGS. It will be appreciated that various functional units may be provided by the control unit, or other specific units in the device, or the network 1.

  Now, a method for carrying out the present invention will be described with reference to the flowcharts of FIGS. FIG. 3 shows steps performed by the mobile terminal 4. The first step of the method is step 101, where the mobile terminal 4 determines parameter measurements for neighboring cells. Next, the mobile terminal reports measurement information to the base station (step 103).

  Referring to FIG. 4, the base station 2 receives measurement information from the mobile terminal 4 (step 107). Here, the measurement information is related to the cell identity (not unique) detected by the mobile terminal 4. If a measurement from a cell identity that was not previously a member of a neighboring cell set is included in the information from the mobile terminal 4, the mobile terminal 4 may also be required to search for a unique cell identity (step 113). The unique cell identity is transmitted from the base station at a much lower frequency than the physical layer identity. In order to receive and decode this information, the mobile terminal 4 may have to interrupt communication with the serving cell for a short time. Once the unique cell identity is retrieved (step 115), this information is transmitted to the serving cell (step 117). When the serving cell receives a unique cell identity (step 119), it can add the newly discovered neighbor cell here to the neighbor cell set (step 121) and establish a transmission connection to that neighbor cell. Good. In a cellular network where several mobile terminals identify new neighboring cells, some filtering is performed on the measurement data, so that it is detected under exceptional propagation conditions, for example when the mobile terminal 4 is in an airplane Obviously, it may be desirable to prevent adding additional distant cells.

  In another example, the mobile terminal 4 can provide unique identity information to the base station 2 without having to receive an instruction to that effect from the base station 2.

  Referring to FIG. 6, base station 2 receives unique identity information (step 119) and then updates the neighbor cell set. Thus, the neighboring cell set includes unique identity information for the cell, and such a cell is determined as a neighboring cell that is a candidate cell for the handover of the mobile terminal 4.

  Utilizing a unique cell identifier (UCID) means that there is clear information regarding the identity of neighboring cells, thereby eliminating confusion about neighboring cells. Non-unique cell identities that are fast and require a small amount of resources for most measurements facilitate the efficient use of resources in the mobile terminal 4 and abrupt handover to neighboring cells. Only when a new neighbor cell is detected, or when an audit of the relationship between a non-unique cell identity and a unique cell identity seems appropriate, the mobile terminal 4 can identify a more cumbersome unique cell identifier. You are required to search.

  All cell relationships can be evaluated continuously. Inputs to this evaluation are mobile terminal reports, mobile terminal events, network events, operator inputs. The result of the evaluation is that the cell (or cell relationship) will retain various properties. It can also be seen that cells (relationships) are in various states.

  The main effect of the embodiment of the present invention is that it eliminates the need for human hands to be involved in the process of maintaining neighboring cell sets. The operator can leave the neighboring cells completely away and let the system determine the neighboring cells.

  Cell lookup associates a unique cell identity (UCID) with the address of the node that implements the cell. For example, in LTE, in normal DNS, a cell identity is associated with an IP address. The IP address then points to the RBS that realizes the cell.

Claims (8)

A method in a wireless communication system defining a plurality of communication cells, wherein a non-unique cell identity and a unique cell identity are transmitted in the plurality of communication cells,
The method
Communicating from a mobile station to a radio base station serving a first communication cell;
(111) transmitting a request for obtaining a unique cell identity of a second communication cell among the plurality of communication cells from the radio base station to the mobile station;
Obtaining the unique cell identity of the second communication cell in the mobile station in response to the request (115);
The radio base station from the mobile station, viewed including the step of reporting the unique cell identity of the acquired second communication cell to a radio base station of the first communication cell (117), a
The unique cell identity of the second communication cell is transmitted less frequently in the second communication cell than the non-unique cell identity of the second communication cell, and each non-unique cell identity Is a physical layer identity, and each unique cell identity is not a physical layer identity . The method of claim 1, comprising:
Performed prior to sending the request;
Determining at the mobile station a non-unique cell identity of the second communication cell (101);
Reporting the non-unique cell identity of the second communication cell from the mobile station to the radio base station (103). The method of claim 2, comprising:
Determining parameter measurements for the second communication cell at the mobile station;
Reporting measurement information from the mobile station to the radio base station along with the non-unique cell identity;
The method, wherein the parameter measurements include one or more of signal strength measurements, signal quality measurements, and timing information. The method according to any one of claims 1 to 3, wherein
The method wherein the second communication cell is adjacent to the first communication cell. A method according to any one of claims 1 to 4, comprising
In the radio base station, by finding in a lookup map a mapping between the unique cell identity of the second communication cell and the network address of the radio base station serving the second communication cell Establishing a transport connection. 6. A method according to claim 5, wherein
The method, wherein the network address is an IP address. The method according to any one of claims 1 to 6, comprising:
The wireless base station further includes the step of adding the second communication cell to a neighbor cell list. A wireless communication network defining a plurality of communication cells, wherein a non-unique cell identity and a unique cell identity are transmitted in the plurality of communication cells;
The network is
Network resources,
Comprising at least one mobile station;
A network operable to perform the method of any one of claims 1-7.

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