JP6929988B2 - Self-configuration and optimization of adjacent cells in wireless telecommunications networks - Google Patents

Description

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

FIG. 1 of the attached drawing shows a wireless telecommunications network. Here, many communication cells (A, B, C, D) are defined in this wireless telecommunications network, and the wireless base station 2 provides a service 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 cell A and can move around the system 1.

The base station 2 includes many receivers and transmitters, and provides one or more cells with a radio coverage area. Each base station 2 is connected to a network "backbone", or core network infrastructure (not shown), which allows 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 adjacent cells. It is typical for the mobile terminal 4 to move around between cells during a call, repeatedly moving from one cell to one of its adjacent cells. For both the network 1 and the mobile terminal 4, in order to make the handover between cells reliable, a list of known adjacent cells, a so-called "neighbor cell set", is important. .. The network 1 can store information about a set of adjacent cells for each mobile terminal. When a mobile terminal crosses a cell boundary using an adjacent cell set, the mobile terminal is evaluated and handed over from one cell to another. It is easy to see that the cell boundaries are not well defined and are actually somewhat blurry, and that the base station ranges will overlap each other.

In the existing system, the mobile terminal 4 detects and measures cell operating parameters for adjacent cells by receiving signals from the surroundings. The measured operating parameters are typically physical layer identifiers, such as scrambled codes, signal strength, signal quality, and timing information that are not uniquely assigned to a cell. The mobile terminal measures the operating parameters of each adjacent cell and reports it to network 1. If the quality of an adjacent cell is determined to be better than the current serviced cell, the network performs a handover from the serviced cell to the selected adjacent cell. Then, the adjacent cell becomes the cell in service to the mobile terminal.

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

The identity of each cell is important when mobile reports adjacent cell signal quality measurements to the network. Today, cell identities (scramble codes) are reused in multiple cells. Reusing identities means that cells in service may have the same identity information as neighboring cells, which may make them 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. In order to resolve the conflict that there are multiple adjacent cells that use the same non-uniqueness identifier as the cell in service, it is necessary to manually perform the work.

An object of the present invention is to reduce the cost of designing and maintaining an adjacent cell set. It is based on the addition of a step that requires the mobile terminal to perform additional work, uniquely identify adjacent cells in the wireless network, and have the mobile terminal report its identity to the network. Embodiments of the present invention are intended to reduce human hand intervention. The method can be carried out as part of an operational support system and base station, or can be carried out only in the RBS. This method is effective for wireless telecommunications technologies such as GSM®, WCDMA®, and LTE.

Indicates a cellular wireless telecommunications network. Indicates a mobile terminal and a base station. The steps of the method of carrying out one aspect of the present invention are shown. The steps of the method of carrying out one aspect of the present invention are shown. The steps of the method of carrying out one aspect of the present invention are shown. The steps of the method of carrying out one aspect of the present invention are shown.

In contrast to the disadvantages of the prior solutions, the present invention provides methods and architectures for maintaining a set of adjacent cells within a mobile cellular network.

FIG. 2 is a schematic view showing a mobile terminal 4 and a base station 2 communicating via an 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 control unit 22 also communicates with other telecommunications 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 functions to control communication between the transmission / reception unit 46 communicating with the air interface 6 and the base station 2 via the antenna 48. Communication with the user of the device is performed using the 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 base stations and mobile terminals are designed to operate according to convention.

However, the base station 2 and the mobile terminal 4 that operate according to the present invention are designed to carry out the method of the present invention described below with reference to FIGS. 3 to 6. It will be appreciated that various functional units can be provided by the control unit, or other specific unit in the device, or network 1.

Here, a method of carrying out the present invention will be described with reference to the flowcharts of FIGS. 3 to 6 and FIG. FIG. 3 shows the steps performed by the mobile terminal 4. The first step of this method is step 101, where the mobile terminal 4 determines parameter measurements for peripheral cells. Next, the mobile terminal reports the measurement information to the base station (step 103).

Looking at FIG. 4, the base station 2 receives the 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 the information from the mobile terminal 4 contains measurements from cell identities that were not previously members of the adjacent cell set, the mobile terminal 4 may also be required to search for a unique cell identity (step). 113). Unique cell identities are transmitted from the base station at a much less frequent cycle than physical layer identities. In order to receive and decrypt this information, the mobile terminal 4 may have to interrupt communication with the cell in service for a short time. Once the unique cell identity has been retrieved (step 115), this information is sent to the serviced cell (step 117). When a serviced cell receives a unique cell identity (step 119), adding a newly discovered adjacent cell here to the adjacent cell set (step 121), even if a send connection to that adjacent cell is established. good. In a cellular network where some mobile terminals identify new adjacent cells, the measurement data is filtered in some way so that it can be detected under exceptional propagation conditions, for example, the mobile terminal 4 is in an airplane. It is clear that it may be desirable to prevent adding distant cells that have been made.

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

Looking at FIG. 6, base station 2 receives unique identity information (step 119) and then updates the adjacent cell set. As described above, the adjacent cell set includes the unique identity information for the cell, and such a cell is determined as an adjacent cell which is a candidate cell for handover of the mobile terminal 4.

Utilizing a unique cell identifier (UCID) means that there is clear information about the identity of an adjacent cell, thereby eliminating confusion about the adjacent cell. The non-unique cell identity, which is fast for most measurements and requires a small amount of resources, facilitates efficient use of resources in the mobile terminal 4 and abrupt handover to an adjacent cell. Only when a new adjacent cell is detected, or when auditing the relationship between the non-unique cell identity and the unique cell identity seems appropriate, the mobile terminal 4 gives the more awkward unique cell identifier. You are required to search.

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

A major effect of embodiments of the present invention is to eliminate the need for human intervention in the process of maintaining adjacent cell sets. It is possible for the operator to leave the adjacent cell completely alone and leave the determination of the adjacent cell to the system.

Cell lookup associates a unique cell identity (UCID) with the address of the node that implements the cell. For example, in LTE, it usually corresponds to DNS, and the cell identity is associated with the IP address. Then, the IP address points to the RBS that realizes the cell.

Claims (20)

A method of operating a mobile terminal in a wireless telecommunications network.
The method is
Communicating with a wireless base station servicing the first cell of the wireless telecommunications network
Determining a non-unique cell identity based on a signal received at the physical layer from a radio base station in a second cell of said wireless telecommunications network.
To report the determined non-unique cell identity to the radio base station providing the service.
Receiving an instruction to detect the unique cell identity of the second cell from the radio base station providing the service, and
In response to the command, receiving an additional signal from the second cell,
Determining a unique cell identity based on additional signals received from the second cell,
A method comprising reporting the unique cell identity to a radio base station providing the service. The additional signal includes data received from said second cell.
The method of claim 1, wherein determining the unique cell identity comprises receiving and decoding the data. The method of claim 1 or 2, wherein the unique cell identity is received within the second cell less frequently than the non-unique cell identity. The method is to measure the signal quality of the signal received in the second cell and
Including reporting the signal quality to the radio base station providing the service.
The method according to any one of claims 1 to 3, wherein the signal quality includes one or more of signal strength measurement, signal quality measurement, and timing information. The reported unique cell identity of the second cell allows the radio base station providing the service to look up the IP address of the radio base station providing the service to the second cell. The method according to any one of claims 1 to 4. The method according to any one of claims 1 to 5, wherein the mobile terminal is an LTE compatible mobile terminal. A mobile terminal that constitutes a wireless telecommunications network
The mobile terminal
Wireless transmitter / receiver and
A control unit paired with the wireless transmission / reception unit is provided.
The control unit passes through the wireless transmission / reception unit.
Communicate with a wireless base station servicing the first cell of the wireless telecommunications network and
Based on the signal received at the physical layer from the radio base station in the second cell of the wireless telecommunications network, a non-unique cell identity is determined.
Report the determined non-unique cell identity to the radio base station providing the service and
Upon receiving an instruction to detect the unique cell identity of the second cell from the radio base station providing the service,
In response to the command, an additional signal is received within the second cell to
Based on the additional signal from the second cell, a unique cell identity is determined.
A mobile terminal that reports the unique cell identity to a radio base station that is providing the service. The additional signal includes data received from said second cell.
The mobile terminal according to claim 7, wherein the control unit determines the unique cell identity by receiving and decoding the data. The mobile terminal according to claim 7 or 8, wherein the unique cell identity is received in the second cell at a lower frequency than the non-unique cell identity. The control unit
The signal quality of the signal received from the second cell is measured, and the signal quality is reported to the radio base station providing the service.
The mobile terminal according to any one of claims 7 to 9, wherein the signal quality includes one or more of signal strength measurement, signal quality measurement, and timing information. The reported unique cell identity of the second cell is that the radio base station providing the service looks up the IP address of the second radio base station providing the service to the second cell. The mobile terminal according to any one of claims 7 to 10, which enables the above. The mobile terminal according to any one of claims 7 to 11, wherein the mobile terminal is an LTE compatible mobile terminal. A node in a wireless telecommunications network
A wireless transmitter / receiver that communicates with a mobile terminal operated in the first cell of the wireless telecommunications network through an air interface.
A control unit paired with the wireless transmission / reception unit is provided.
The control unit
Upon receiving the non-unique cell identity of the second cell of the wireless telecommunications network from the mobile terminal,
Requesting the mobile terminal to also acquire the unique cell identity of the second cell,
When the second cell is not included in the adjacent cell set of the first cell, the mobile terminal receives the unique cell identity of the second cell and receives the unique cell identity of the second cell.
The mobile terminal
The non-unique cell identity is determined based on the signal received at the physical layer from the radio base station in the second cell of the wireless telecommunications network.
A node that determines the unique cell identity based on a signal received from a radio base station in the second cell. The control unit
13. A transmission connection is established by finding a mapping between the unique cell identity of the second cell and the network address of the radio base station servicing the second cell in the lookup map. Nodes listed in. The control unit
13. Receiving the non-unique identity associated with the operating parameter of at least one said second cell, including at least one of a scrambled code, a signal strength measure, a signal quality measure, and timing information. Described node. The control unit
13. The node according to claim 13, which receives unique cell identities of a plurality of cells from the mobile terminal. A method at the node of a wireless telecommunications network,
The non-unique cell identity of the second cell of the wireless telecommunications network is received through the air interface from the mobile terminal operated in the first cell of the wireless telecommunications network.
Requesting the mobile terminal to also acquire the unique cell identity of the second cell,
When the second cell is not included in the adjacent cell set of the first cell, the mobile terminal receives the unique cell identity of the second cell and receives the unique cell identity of the second cell.
The mobile terminal
The non-unique cell identity is determined based on the signal received at the physical layer from the radio base station in the second cell of the wireless telecommunications network.
A method of determining the unique cell identity based on a signal received from a radio base station in the second cell. 17. A transmission connection is established by finding a mapping between the unique cell identity of the second cell and the network address of the radio base station servicing the second cell in the lookup map. The method described in. 17. Claim 17, which receives the non-unique identity associated with the operating parameter of at least one said second cell, including at least one of a scrambled code, a signal strength measure, a signal quality measure, and timing information. The method described. 17. The method of claim 17, wherein the mobile terminal receives unique cell identities of a plurality of cells.

Images