JP2011114586A - Radio communication system, radio base station and network device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the transmission power of a radio base station while suppressing the deterioration of communication service quality. <P>SOLUTION: In this radio communication system 1, two adjacent radio base stations 100 belong to different groups, and time zones where the transmission power falls off in the radio base stations 100 are different at each group. In order to attain such grouping, a network device 10 in a high order of the radio base station devices 100 performs the grouping so that the two adjacent radio base stations 100 belong to the different groups by dividing the respective radio base stations 100 into four groups byso-called the four-color theorem. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio communication system having a plurality of radio base stations, a radio base station constituting the radio communication system, and a network apparatus in a higher rank of the radio base station.

  In a wireless communication system, when maintenance work for a wireless base station is performed, the wireless base station performs processing (blocking processing) for stopping transmission power. In this blocking process, the radio base station does not accept a new call indicating a call that is newly generated by the radio terminal. In addition, when there is an existing call indicating a call that is continuing communication between the radio base station and the radio terminal, the radio base station performs handover of the existing call to another adjacent radio base station. Then, the transmission power is stopped (see, for example, Patent Document 1). Such a process is called a pre-occlusion process. Further, from the viewpoint of energy saving, it has been proposed to reduce the transmission power of a radio base station in a time zone with a small amount of communication such as at night.

Japanese Patent Laid-Open No. 10-209947

  However, when maintenance work is performed by stopping a plurality of radio base stations constituting the radio communication system one by one, it takes a long time until the maintenance work of all the radio base stations is completed. On the other hand, in order to shorten the maintenance work time, it is conceivable to simultaneously stop the transmission power of a plurality of radio base stations. However, if two adjacent radio base stations simultaneously stop transmission power, a wide dead zone may occur. Similarly, when reducing the transmission power of a radio base station from the viewpoint of energy saving, if a plurality of adjacent radio base stations simultaneously stop transmission power, a wide dead zone may occur.

  In view of the above problems, an object of the present invention is to provide a radio communication system, a radio base station, and a network device that reduce transmission power of a radio base station while suppressing deterioration in quality of communication services.

  In order to solve the above-described problems, the present invention has the following features. A first feature of the present invention is a wireless communication system having a plurality of wireless base stations, wherein two adjacent wireless base stations belong to different groups, and a time zone in which transmission power decreases in the wireless base station The gist is that it differs for each group.

  In such a wireless communication system, two adjacent wireless base stations belong to different groups, and the time periods during which the transmission power decreases are different. Therefore, as a result of two adjacent radio base stations stopping transmission power at the same time, a wide dead zone does not occur, and the transmission power of the radio base station is reduced while suppressing deterioration of the quality of communication service. Is possible.

  According to a second aspect of the present invention, there is provided a network device at an upper level of the radio base station, and the network device performs grouping to divide the plurality of radio base stations into four or more groups according to a predetermined condition. The gist is to include a grouping processing unit (grouping processing unit 52) to perform.

  According to a third aspect of the present invention, when the radio base station is added to the radio communication system, or when another radio base station is excluded from the radio communication system, The gist of the invention is that it includes a regrouping processing unit (regrouping processing unit 156) that performs regrouping processing to divide the plurality of radio base stations into groups again using inter-base station communication.

  A fourth feature of the present invention is a radio base station that constitutes a radio communication system together with another radio base station, and a plurality of groups together with other radio base stations so that adjacent radio base stations belong to different groups. And a transmission power control unit (transmission power control unit 154) that reduces transmission power in the same time zone as other radio base stations belonging to the same group as the own radio base station. .

  According to a fifth aspect of the present invention, there is provided a network device in a higher rank of a plurality of radio base stations constituting a radio communication system, wherein the plurality of radio base stations are divided into four or more groups according to a predetermined condition. A grouping processing unit (grouping processing unit 54) that performs grouping is provided, and the gist of the invention is that the time zone in which the transmission power decreases in the radio base station differs for each group.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to reduce the transmission power of a wireless base station, suppressing the deterioration of the quality of a communication service.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. 1 is a configuration diagram of a network device according to an embodiment of the present invention. It is a figure which shows an example of adjacent base station information. It is a figure which shows an example of grouping information. It is a block diagram of the radio base station which concerns on embodiment of this invention. It is a sequence diagram which shows operation | movement of the initial grouping of the radio | wireless communications system which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement of the regrouping of the wireless base station which concerns on embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) the configuration of the wireless communication system, (2) the operation of the wireless communication system, (3) the operation and effect, and (4) other embodiments will be described. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) Configuration of Radio Communication System (1.1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system 1 according to an embodiment of the present invention. The wireless communication system 1 shown in FIG. 1 is based on, for example, LTE Release 9 that is a 3.9th generation (3.9G) mobile phone system or LTE-Advanced that is positioned as a 4th generation (4G) mobile phone system. It has a configuration.

  As shown in FIG. 1, the radio communication system 1 includes a network device 10 and radio base stations 100a to 100s. The network apparatus 10 is an apparatus such as an MME (Mobility Management Entity) that is connected to the radio base stations 100a to 100t via a network (not shown) and performs various controls on the upper level of the radio base stations 100a to 100t. In the following, when the radio base stations 100a to 100t are not distinguished, they are simply referred to as “radio base station 100”.

  In the present embodiment, each radio base station 100 is divided into four groups by grouping processing. In this case, grouping processing is performed so that two adjacent radio base stations 100 belong to different groups. Here, “adjacent” is defined as follows. That is, the radio base stations 100 a to 100 t in the radio communication system 1 are connected to each other by the link 101. At this time, the link 101 is set so as not to cross the other link 101. Here, when the two links 101 intersect, it is preferable to avoid the intersection by preferentially setting the link 101 having a short distance. In other words, as the distance between the radio base stations 100 is shorter, it is preferable that the link 101 is preferentially set between the radio base stations 100. In a state where the link 101 is set in this way, the two radio base stations 100 located at both ends of the one link 101 are adjacent to each other.

  According to the so-called four-color theorem, if each radio base station 100 is divided into at least four groups, two adjacent radio base stations 100 can belong to different groups. Therefore, in this embodiment, in order to satisfy the condition that two adjacent radio base stations 100 belong to different groups, each radio base station 100 in the radio communication system 1 is divided into four groups.

  In FIG. 1, each radio base station 100 includes a radio base station 100a, 100h, 100j, 100p, and 100s corresponding to black, and a radio base station 100e, 100l, 100o, 100q, and 100t corresponding to white. The second group to which the radio base stations 100b, 100d, 100f, 100i, and 100m belong, and the radio base stations 100c, 100g, 100k, and 100n that correspond to the downward stripe pattern , 100r belong to a fourth group.

  By such grouping, two adjacent radio base stations 100 belong to different groups. For example, when paying attention to the radio base station 100q belonging to the second group, if the radio base station 100c, 100d, 100r, 100j, 100k, 100p adjacent to the radio base station 100q is confirmed, the radio base station 100c is the fourth group, radio base station 100d is the third group, radio base station 100r is the fourth group, radio base station 100j is the first group, radio base station 100k is the third group, and radio base station 100p is the first group. These are all different from the second group to which the radio base station 100q belongs.

  In the present embodiment, when the network device 10 performs an initial grouping process and then a radio base station is added to the radio communication system 1 or when a radio base station is excluded from the radio communication system 1. Each radio base station 100 performs grouping processing (regrouping processing) again.

(1.2) Configuration of Network Device FIG. 2 is a configuration diagram of the network device 10. As illustrated in FIG. 2, the network device 10 includes a control unit 12, a storage unit 13, and a wired communication unit 14.

  The control part 12 is comprised by CPU, for example, and controls the various functions with which the network apparatus 10 is provided. The storage unit 13 is configured by a memory, for example, and stores various types of information used for control and the like in the network device 10. The wired communication unit 104 transmits and receives data to and from the radio base station 100 via a network (not shown). In communication between the network device 10 and the radio base station 100, for example, an S1 connection as a logical communication path is established in a network (not shown).

  The control unit 12 includes a base station information acquisition unit 52 and a grouping processing unit 54.

  The base station information acquisition unit 52 acquires position information including the longitude and latitude of the radio base station 100 for each radio base station 100 and a base station ID that is identification information of the radio base station. The location information is transmitted from the radio base station 100, for example. In this case, the base station information acquisition unit 52 inputs position information from the radio base station 100 received by the wired communication unit 14. Alternatively, the position information is stored in advance in the storage unit 13. In this case, the base station information acquisition unit 52 reads position information from the storage unit 13.

  Further, the base station information acquisition unit 52 acquires the operating state information of the radio base station 100 for each radio base station 100. The operating state information is information indicating whether the corresponding radio base station 100 is operating or is stopped due to a failure or the like. This operating state information is transmitted from the radio base station 100, for example. In this case, the base station information acquisition unit 52 inputs operation state information received by the wired communication unit 14. Alternatively, the operating state information is stored in the storage unit 13 in advance. In this case, the base station information acquisition unit 52 reads the operating state information from the storage unit 13.

  The grouping processing unit 54 performs an initial grouping process based on the position information and operation state information for each radio base station 100 acquired by the base station information acquisition unit 52.

  Specifically, the grouping processing unit 54 sets, as a node, the radio base station 100 indicating that the corresponding operation information state is operating among the radio base stations 100 in the radio communication system 1. Then, a plane graph in which a link connecting two adjacent radio base stations 100 is set is created. Here, when setting the link, the grouping processing unit 54 specifies the position of each radio base station 100 based on the position information of each radio base station 100 set as a node, and the link does not intersect. Set the link as follows.

  Next, the grouping processing unit 54 includes, for each radio base station 100 set as a node, the base station ID of the radio base station 100 as a reference base station ID, and other radio base stations adjacent to the radio base station 100 Neighboring base station information including the base station ID of the station 100 as the neighboring base station ID is generated. The generated adjacent base station information is stored in the storage unit 13. FIG. 3 is a diagram illustrating an example of adjacent base station information.

  Next, for each radio base station 100 set as a node, the grouping processing unit 54 uses the vertex coloring method so that the two adjacent radio base stations 100 belong to different groups. Divide into 4 groups of 4 groups. Here, each of the first to fourth groups is associated with a group ID as identification information. In addition, the first to fourth groups are associated with different transmission time reduction time zones.

  Next, the grouping processing unit 54 generates grouping information for each radio base station 100 set as a node. Specifically, the grouping processing unit 54 includes, for each radio base station 100, adjacent base station information corresponding to the radio base station 100, that is, the base station ID of the radio base station 100 as a reference base station ID. The adjacent base station information is read from the storage unit 13. Next, the grouping processing unit 54 transmits, to the reference base station ID in the read adjacent base station information, a group ID corresponding to the group to which the radio base station 100 specified by the reference base station ID belongs, and transmission power Add a drop time zone. Further, the grouping processing unit 54 sets the group ID corresponding to the group to which the radio base station 100 specified by the adjacent base station ID belongs to the adjacent base station ID in the read adjacent base station information, and the transmission power reduction. Add time zone. FIG. 4 is a diagram illustrating an example of grouping information.

  In this way, after generating grouping information for each radio base station 100 set as a node, the grouping processing unit 54 identifies each grouping information by the reference base station ID in the grouping information. The wireless base station 100 to be transmitted is transmitted via the wired communication unit 104.

(1.3) Configuration of Radio Base Station FIG. 5 is a configuration diagram of the radio base station 100. As illustrated in FIG. 5, the radio base station 100 includes a control unit 102, a storage unit 103, a wired communication unit 104, a radio communication unit 106, and an antenna 108.

  The control unit 102 is configured using a CPU, for example, and controls various functions provided in the radio base station 100. The storage unit 103 is configured using, for example, a memory, and stores various types of information used for controlling the radio base station 100 and the like. The wired communication unit 104 communicates with the network device 10 and other wireless base stations 100 via a network (not shown). In communication between the radio base station 100 and another radio base station 100, for example, an X2 connection as a logical communication path is established in a network (not shown).

  The wireless communication unit 106 is configured using, for example, a radio frequency (RF) circuit, a baseband (BB) circuit, and the like, and transmits and receives a wireless signal to and from a wireless terminal (not shown) via the antenna 108. In addition, the wireless communication unit 106 performs encoding and modulation of the transmission signal and demodulation and decoding of the reception signal.

  The control unit 102 includes a grouping information acquisition unit 152, a transmission power control unit 154, and a regrouping processing unit 156.

  The grouping information acquisition unit 152 acquires grouping information from the network device 10 via a network (not shown) and the wired communication unit 104. Further, the grouping information acquisition unit 152 causes the storage unit 103 to store the acquired grouping information.

  The transmission power control unit 154 reads the grouping information stored in the storage unit 103. Furthermore, when the transmission power reduction time zone in the read grouping information comes, the transmission power control unit 154 controls the wireless communication unit 106 to reduce the transmission power. Here, the decrease in transmission power includes a case where transmission power stops. In the radio base stations 100 belonging to the same group, the transmission power decrease time period is the same. Therefore, the radio base stations 100 belonging to the same group reduce the transmission power in the same transmission power reduction time zone. Moreover, the transmission power reduction time zone corresponding to each group is different. Further, two adjacent radio base stations 100 belong to different groups. Therefore, two adjacent radio base stations 100 do not simultaneously reduce transmission power.

  When a radio base station is added to the radio communication system 1 or when a radio base station is excluded from the radio communication system 1, the regroup processing unit 156 performs a regrouping process (regrouping process). )I do.

  Specifically, the regrouping processing unit 156 identifies another radio base station 100 adjacent to the own radio base station 100 based on the adjacent base station ID in the grouping information. Next, the regrouping processing unit 156 transmits the group ID (affiliation) of the group to which the own radio base station 100 belongs to the other specified adjacent radio base stations 100 via the wired communication unit 104 and a network (not shown). Group ID). Further, the regrouping processing unit 156 transmits the group ID (affiliation group) of the group to which the other adjacent radio base station 100 belongs from the other adjacent radio base station 100 via the network and wired communication unit 104 (not shown). ID). In each radio base station 100, the regrouping processing unit 156 in the control unit 102 performs the above-described processing, so that the group ID of the group to which the radio base station 100 belongs between two adjacent radio base stations 100. Will be replaced.

  Next, the regrouping processing unit 156 performs the adjacent processing based on the group IDs corresponding to all the adjacent base station IDs in the grouping information and the belonging group IDs from all the other adjacent radio base stations 100. It is determined whether or not the group to which the other radio base station 100 belongs has changed. Specifically, the regrouping processing unit 156, for each other adjacent radio base station 100, the group ID corresponding to the other adjacent radio base station 100 in the grouping information, and the other adjacent radio base station 100 The group IDs from the radio base station 100 are compared, and if they match, it is determined that there is no change in the group to which the other adjacent radio base station 100 belongs. It is determined that a change has occurred in the group to which the wireless base station 100 belongs.

  When a change is made to a group to which another adjacent radio base station 100 belongs, the regrouping processing unit 156 further includes a group ID that is a group ID of the group after the change and a group of the group to which the own radio base station 100 belongs. Compare the ID. When the two group IDs match, the own radio base station 100 and another adjacent radio base station 100 belong to the same group. In this case, the regrouping processing unit 156 changes the group to which the own radio base station 100 belongs. Further, the regrouping processing unit 156 transmits the group ID of a new group to which the own radio base station 100 belongs to another adjacent radio base station 100 via the wired communication unit 104 and a network (not shown). .

  By performing the above-described processing until the groups to which two adjacent radio base stations 100 belong become different, each radio base station 100 autonomously performs regrouping.

(2) Operation of Radio Communication System Next, the operation of the radio communication system 1 will be described. FIG. 6 is a sequence diagram showing an initial grouping operation of the wireless communication system 1.

  In step S <b> 100, the network device 10 acquires location information for each radio base station 100. Furthermore, the network device 10 acquires operating state information for each wireless base station 100.

  In step S <b> 101, the network device 10 performs an initial grouping process for each radio base station 100 based on the acquired position information and operation state information for each radio base station 100. In the initial grouping process, the network device 10 generates grouping information for each radio base station 100.

  In step S <b> 102, the network device 10 transmits grouping information to the radio base station 100. The radio base station 100 receives the grouping information from the network device 10.

  Thereafter, in step S103, when the transmission power reduction time zone in the grouping information arrives, the radio base station 100 performs control to reduce the transmission power.

  FIG. 7 is a flowchart showing the regrouping operation of the radio base station 100.

  In step S <b> 200, the radio base station 100 transmits the belonging group ID corresponding to the own radio base station 100 to another adjacent radio base station 100. Furthermore, in step S <b> 201, the radio base station 100 receives a belonging group ID corresponding to the adjacent radio base station 100 from another adjacent radio base station 100.

  In step S202, the radio base station 100 determines whether or not the group to which another adjacent radio base station 100 belongs has changed.

  When the group to which another adjacent radio base station 100 belongs has not changed, the series of operations ends. On the other hand, when the group to which another adjacent radio base station 100 belongs has changed, in step S203, the radio base station 100 performs a regrouping process.

  Further, in step S204, the radio base station 100 transmits the group ID (affiliation group ID) of the group to which the own radio base station 100 newly belongs as a result of the regrouping process to another adjacent radio base station 100. To do.

(3) Operation / Effect In the wireless communication system 1 according to the embodiment of the present invention, two adjacent wireless base stations 100 belong to different groups, and the time zone in which the transmission power decreases in the wireless base station 100 is a group. Every one is different.

  In order to realize such grouping, the network device 10 in the upper layer of the radio base station 100 divides each radio base station 100 into four groups by the so-called four-color theorem, so that two adjacent radio base stations 100 Grouping is performed so that the stations 100 belong to different groups.

  Thereby, in order to shorten the maintenance work time, when stopping the transmission power of a plurality of radio base stations 100 simultaneously, or when reducing the transmission power of the radio base station from the viewpoint of energy saving, As a result of the two adjacent radio base stations 100 stopping transmission power simultaneously, a wide dead zone does not occur, and the transmission power of the radio base station 100 is reduced while suppressing deterioration in the quality of communication services. Is possible.

  In the wireless communication system 1 according to the present embodiment, when a wireless base station is added to the wireless communication system 1 or when a wireless base station is excluded from the wireless communication system 1, each wireless base station 100 exchanges the group ID of the group to which the own radio base station 100 belongs with another adjacent radio base station 100 by inter-base station communication. Thereby, each radio base station 100 can specify the group to which the other adjacent radio base station 100 belongs, and the own radio base station according to the change of the group to which the other adjacent radio base station 100 belongs. A regrouping process of changing the group to which 100 belongs can be performed. Furthermore, the radio base station 100 transmits the group ID of the group to which the own radio base station 100 newly belongs to another adjacent radio base station 100. Thereby, it is possible to notify another adjacent radio base station 100 of a group to which the own radio base station 100 newly belongs, and to perform the regrouping process also in the adjacent other radio base station 100. Become.

(4) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, in order to satisfy the condition that two adjacent radio base stations 100 belong to different groups, each radio base station 100 in the radio communication system 1 is divided into four groups. It may be divided into the above groups. For example, when each radio base station 100 in the radio communication system 1 is divided into five groups, a radio base station is added to the radio communication system 1 or a radio base station is excluded from the radio communication system 1 In the regrouping process in the case of being performed, it is possible to limit the range of the radio base station 100 in which the group is changed.

  In the above-described embodiment, the wireless communication system 1 is configured based on LTE Release 9 or LTE-Advanced, but may be configured based on other communication standards.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

  The wireless communication system, the wireless base station, and the network device of the present invention can reduce the transmission power of the wireless base station while suppressing the deterioration of the quality of the communication service, and are useful as a wireless communication system or the like.

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 10 ... Network apparatus, 12 ... Control part, 13 ... Memory | storage part, 14 ... Wired communication part, 52 ... Base station information acquisition part, 54 ... Grouping process part, 100a-100t ... Wireless base station, DESCRIPTION OF SYMBOLS 102 ... Control part, 103 ... Memory | storage part, 104 ... Wired communication part, 106 ... Wireless communication part, 108 ... Antenna, 152 ... Grouping information acquisition part, 154 ... Transmission power control part, 156 ... Regrouping process part

Claims (5)

A wireless communication system having a plurality of wireless base stations,
Two adjacent radio base stations belong to different groups,
A radio communication system in which a time zone in which transmission power decreases in the radio base station differs for each group. Having a network device above the radio base station,
The wireless communication system according to claim 1, wherein the network device includes a grouping processing unit that performs grouping to divide the plurality of wireless base stations into four or more groups according to a predetermined condition.   The radio base station uses inter-base station communication when another radio base station is added to the radio communication system, or when another radio base station is excluded from the radio communication system, The radio | wireless communications system of Claim 1 or 2 provided with the regrouping process part which performs the regrouping process which divides | segments a some radio base station into a group again. A radio base station that constitutes a radio communication system with other radio base stations,
It is divided into a plurality of groups together with other radio base stations so that two adjacent radio base stations belong to different groups.
A radio base station comprising a transmission power control unit that reduces transmission power in the same time zone as other radio base stations belonging to the same group as the own radio base station. A network device above a plurality of radio base stations constituting a radio communication system,
A grouping processing unit that performs grouping to divide the plurality of radio base stations into four or more groups according to a predetermined condition,
A network device in which a time zone in which transmission power decreases in the radio base station differs for each group.

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