JP2011061456A - Communication system, mobile station device, and base station apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently balance loads between frequency bands by correcting the balance of the loads between the frequency bands. <P>SOLUTION: The communication system includes the mobile station device 1 and the base station apparatus 3A, and performs load balancing for distributing the loads for the respective frequency bands allocated to the mobile station device 1. When the load balancing is required in a specified frequency band, the base station apparatus 3A transmits paging in which a load balancing index indicating the execution of the load balancing is set to the mobile station device 1 in a standby state (S404). When the load balancing index is set in the received paging, the mobile station device 1 in the standby state sets again a parameter required for executing cell reselection and executes the cell reselection using the reset parameter (S405). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system, a mobile station apparatus, and a base station apparatus that can efficiently balance loads in a plurality of frequency bands.

  Evolved Universal Terrestrial Radio Access (hereinafter referred to as EUTRA), which evolved the 3rd generation mobile communication system in 3GPP (3rd Generation Partnership Project), which is a standardization project, and Advanced EUTRA (also referred to as LTE-Advanced), which is a further development Is under consideration.

  In Advanced EUTRA, introduction of technologies such as carrier aggregation and relay transmission (Relay) has been proposed in order to maintain higher compatibility with EUTRA and improve higher-speed data transmission and throughput ( Non-patent document 1).

  In Advanced EUTRA, a base station apparatus and a mobile station apparatus are connected using a plurality of frequency bands (multi-carriers) by carrier aggregation, and a base station apparatus and a mobile station apparatus are connected to one frequency band as in EUTRA. (Single carrier) may be used for connection. Mobile station devices that do not support carrier aggregation (including EUTRA mobile station devices) are connected using one frequency band. At this time, if mobile station devices connected using one frequency band are concentrated in a certain frequency band, the occupancy rate of the control signal in the radio resource increases in that frequency band, and conversely the data A problem arises in that satisfactory throughput cannot be obtained due to a decrease in the amount of radio resources that can be allocated for transmission. Therefore, in a base station apparatus having a plurality of frequency bands, it is necessary to perform load balancing for correcting the load balance for each frequency band so that the mobile station apparatus is not concentrated on a certain frequency band.

  However, although the cell selection method and cell reselection method in EUTRA are performed by the mobile station apparatus, cell selection / cell reselection is not performed in consideration of load balancing (Non-patent Document 2). That is, the load balancing in EUTRA is led by the base station apparatus when the mobile station apparatus is connected (radio resource control connection state; RRC_Connected). For example, in Non-Patent Document 3, a frequency at which a base station apparatus once releases a radio resource control connection (RRC Connection) of a mobile station apparatus and moves to a layer 3 message instructing the release by cell reselection. There has been proposed a method in which bandwidth priorities are individually set and transmitted.

3GPP TR36.814, Further Advancements for E-UTRA, Physical Layer Aspects.V1.0.0; http: //www.3gpp.org/ftp/Specs/html-info/36814.htm 3GPP TS36.304, User Equipment (UE) procedures in idle mode.V8.6.0; http: //www.3gpp.org/ftp/Specs/html-info/36304.htm 3GPP TSG-RAN WG2 LTE RRC ad-hoc, R2-075561, Vienna, Austria 13-14th December 2007

  As described above, EUTRA does not introduce a load balancing control method led by a mobile station apparatus. For this reason, control for distributing (equalizing) the load according to the actual load situation has to be performed while the mobile station apparatus is connected to the base station apparatus. Therefore, even when balancing between frequency bands is necessary, there is a problem that the base station device cannot move a mobile station device that is not connected to the base station device to a different frequency.

  Further, since the conventional load balancing method is performed by once releasing the radio resource control connection of the mobile station apparatus to which the base station apparatus is connected, the power consumption of the mobile station apparatus increases and the radio resource control connection There has been a problem that processing delay occurs with the release of.

  In view of the above problems, the present invention provides a communication system, a mobile station apparatus, and a base station apparatus capable of correcting the load balance between frequency bands and efficiently balancing the load between frequency bands. The purpose is to provide.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, a communication system according to the present invention includes a mobile station device and a base station device, and performs load balancing for distributing a load for each frequency band assigned to the mobile station device, wherein the base station device When the load balance is necessary in a specific frequency band, the mobile station apparatus in the standby state transmits a paging in which a load balance index indicating the execution of the load balance is set to the mobile station apparatus in the standby state. If the load balancing indicator is set in the received paging, reset parameters necessary for performing cell reselection, and perform cell reselection using the reset parameters. Features.

  As described above, when the load balancing index is set in the received paging, the mobile station apparatus in the standby state resets the parameters necessary for performing cell reselection, and uses the reset parameters to Since the reselection is performed, the base station apparatus can notify the mobile station apparatus of the execution of the load balancing control using paging, thereby eliminating the need for adding a dedicated message for the load balancing control. , Consumption of radio resources can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, it is more than the conventional method in which control is individually notified for each connected mobile station device. Also, load balancing can be performed efficiently. Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control.

  Moreover, since the load balance is corrected by balancing the load between the frequency bands, the radio resources can be effectively used, and the throughput is improved. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (2) In the communication system of the present invention, the communication system includes a mobile station apparatus and a base station apparatus, and performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus, When the load balancing is necessary in a specific frequency band, the station apparatus has a load balancing index indicating the execution of the load balancing and the ratio of the mobile station apparatus performing the load balancing with respect to the mobile station apparatuses in the standby state. When the mobile station apparatus in the standby state sets the load balance index and the load balance coefficient in the received paging, the mobile station apparatus in the standby state transmits a randomly selected value and the paging The load balance coefficient is compared, and based on the comparison result, parameters necessary for executing cell reselection are reset, and the reset parameter is reset. And wherein the performing cell reselection using the meter.

  As described above, when the load balance index and the load balance coefficient are set in the received paging, the mobile station apparatus in the standby state compares the randomly selected value with the load balance coefficient, and based on the comparison result, The parameters necessary for executing cell reselection are reset, and cell reselection is executed using the reset parameters. Therefore, the base station apparatus uses the paging to implement load balancing control to the mobile station apparatus. This can be notified, and it is not necessary to add a dedicated message for load balancing control, and consumption of radio resources can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, the radio resources can be effectively used, and the throughput is improved. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  Further, since the base station device transmits paging with a load balancing coefficient indicating the proportion of mobile station devices that perform load balancing to the mobile station device that is waiting, a plurality of a predetermined proportion of standby The mobile station apparatus can be notified of the execution of control all at once by one paging, and the number of paging transmissions necessary for load balancing can be suppressed, so that the utilization efficiency of radio resources is improved. In addition, it is possible to shorten the time required to complete load balancing between frequency bands.

  (3) Moreover, in the communication system of the present invention, the parameter includes a frequency priority indicating a priority of a serving frequency in which the mobile station device is located, and the mobile station device broadcasts from the base station device. The cell reselection is performed by resetting the frequency priority of the serving frequency notified by the information to the lowest value.

  Thus, the mobile station apparatus resets the frequency priority of the serving frequency notified by the broadcast information from the base station apparatus to the lowest value and performs cell reselection. It can be diverted, and no additional function is required for realization, and control is simplified.

  (4) In the communication system according to the present invention, the parameter includes a frequency priority indicating a priority order for each frequency band, and the mobile station apparatus is notified by broadcast information from the base station apparatus. The cell reselection is performed by resetting the frequency priority indicated by the paging instead of the frequency priority of the different frequency different from the service frequency and the service frequency.

  In this way, the mobile station apparatus resets the frequency priority indicated by paging instead of the in-service frequency notified by the broadcast information from the base station apparatus and the frequency priority of a different frequency different from the in-service frequency. Since cell reselection is performed, different frequencies that move due to cell reselection can be selected based on the frequency priority according to the load status for each frequency band, and efficient load balancing can be realized. Can do.

  (5) In addition, the mobile station apparatus of the present invention includes a mobile station apparatus and a base station apparatus, and is applied to a communication system that performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus. If the load balancing index indicating the execution of load balancing is set in the paging received in the standby state in the station apparatus, parameters necessary for performing cell reselection are reset, and the resetting is performed. It is characterized in that cell reselection is carried out using the selected parameters.

  As described above, when a load balancing index indicating the load balancing is set in the paging received in the standby state, the mobile station apparatus resets the parameters necessary for performing cell reselection, and resets the parameters. Since the cell reselection is executed using the set parameters, the base station apparatus can notify the mobile station apparatus of the execution of load balancing control using paging, and a dedicated message for load balancing control is added. This eliminates the need to perform wireless resource consumption. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently. Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control.

  Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (6) The mobile station apparatus of the present invention includes a mobile station apparatus and a base station apparatus, and is applied to a communication system that performs load balancing that distributes a load for each frequency band allocated to the mobile station apparatus. If the paging received in the standby state is set with a load balance index indicating the load balance and a load balance coefficient indicating the ratio of the mobile station devices performing the load balance, the paging received in the standby state is randomly The selected value is compared with the load balance coefficient, the parameter necessary for executing cell reselection is reset based on the comparison result, and the cell reselection is executed using the reset parameter. It is characterized by that.

  As described above, when the mobile station apparatus is set to the paging received in the standby state, the load balance index indicating the execution of load balance and the load balance coefficient indicating the ratio of the mobile station apparatuses performing the load balance are set randomly. Compare the selected value with the load balance coefficient, reset the parameters necessary to perform cell reselection based on the comparison result, and perform cell reselection using the reset parameters, The base station apparatus can notify the mobile station apparatus of execution of load balancing control by using paging, and it is not necessary to add a dedicated message for load balancing control, and consumption of radio resources can be suppressed. . In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  In addition, since a load balancing coefficient indicating the ratio of mobile station apparatuses that perform load balancing is set in the mobile station apparatus, the base station apparatus applies a certain ratio to a plurality of mobile station apparatuses that are waiting. The execution of control can be notified all at once by one paging, and the number of transmissions of paging necessary for load balancing can be suppressed, so that the utilization efficiency of radio resources is improved. In addition, it is possible to shorten the time required to complete load balancing between frequency bands.

  (7) Moreover, in the mobile station apparatus of the present invention, the parameter includes a frequency priority indicating a priority of a serving frequency in which the own station is located, and the serving area notified by broadcast information from the base station apparatus Cell reselection is performed by resetting the frequency priority of the frequency to the lowest value.

  Thus, the mobile station apparatus resets the frequency priority of the serving frequency notified by the broadcast information from the base station apparatus to the lowest value and performs cell reselection. It can be diverted, and no additional function is required for realization, and control is simplified.

  (8) In the mobile station apparatus of the present invention, the parameter includes a frequency priority indicating a priority order for each frequency band, and the in-service frequency and the in-service area notified from the base station apparatus by broadcast information. Instead of the frequency priority of a different frequency different from the frequency, the frequency priority indicated by the paging is reset and cell reselection is executed.

  In this way, the mobile station apparatus resets the frequency priority indicated by paging instead of the in-service frequency notified by the broadcast information from the base station apparatus and the frequency priority of a different frequency different from the in-service frequency. Since cell reselection is performed, different frequencies that move due to cell reselection can be selected based on the frequency priority according to the load status for each frequency band, and efficient load balancing can be realized. Can do.

  (9) The mobile station apparatus of the present invention includes a mobile station apparatus and a base station apparatus, and is applied to a communication system that performs load balancing that distributes a load for each frequency band allocated to the mobile station apparatus. A station apparatus that receives a paging from the base station apparatus in a standby state, and performs a cell reselection when the received paging is set with a load balancing index indicating the implementation of the load balancing A cell selection unit that resets parameters necessary for the resetting and performs cell reselection using the reset parameters.

  As described above, the mobile station apparatus receives paging from the base station apparatus in the standby state, and is necessary for performing cell reselection when the received paging is set with a load balance index indicating implementation of load balance. Therefore, the base station apparatus can notify the mobile station apparatus that the load balancing control is performed using paging, and the load balancing control is performed. Therefore, it is not necessary to add a dedicated message for the wireless communication, and consumption of radio resources can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (10) A mobile station apparatus according to the present invention includes a mobile station apparatus and a base station apparatus, and is applied to a communication system that performs load balancing that distributes a load for each frequency band allocated to the mobile station apparatus. A receiving unit that receives paging from the base station device in a standby state, and a ratio of a mobile station device that performs load balancing on the received paging and a load balancing index indicating execution of the load balancing When a load balance coefficient indicating is set, a value selected at random is compared with the load balance coefficient, and based on the comparison result, parameters necessary for performing cell reselection are reset, A cell selection unit that performs cell reselection using the reset parameter.

  In this way, the mobile station apparatus receives the paging from the base station apparatus in the standby state, the load balance index indicating the load balance execution and the ratio of the mobile station apparatus performing the load balance to the received paging. When the load balance factor shown is set, the value selected at random is compared with the load balance factor, and the parameters necessary to perform cell reselection are reset and reset based on the comparison result. Since the cell reselection is performed using the parameters, the base station apparatus can notify the mobile station apparatus of the execution of the load balancing control using paging, and therefore a dedicated message for the load balancing control is added. This eliminates the need for radio resource consumption. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  In addition, since a load balancing coefficient indicating the ratio of mobile station apparatuses that perform load balancing is set in the mobile station apparatus, the base station apparatus applies a certain ratio to a plurality of mobile station apparatuses that are waiting. The execution of control can be notified all at once by one paging, and the number of transmissions of paging necessary for load balancing can be suppressed, so that the utilization efficiency of radio resources is improved. In addition, it is possible to shorten the time required to complete load balancing between frequency bands.

  (11) A base station apparatus according to the present invention is a base station apparatus that includes a mobile station apparatus and a base station apparatus, and performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus, When the load balance is necessary in a specific frequency band, paging with a load balance index indicating execution of the load balance is transmitted to the mobile station apparatus in a standby state.

  In this way, when load balancing is necessary in a specific frequency band, the base station device transmits paging in which a load balancing index indicating execution of load balancing is set to the standby mobile station device. It is not necessary to add a dedicated message for load balancing control, and consumption of radio resources can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (12) A base station apparatus according to the present invention is a base station apparatus that includes a mobile station apparatus and a base station apparatus, and performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus, When the load balance is necessary in a specific frequency band, the load balance index indicating the load balance index indicating the execution of the load balance and the ratio of the mobile station devices performing the load balance for the mobile station devices in the standby state A paging with a coefficient set is transmitted.

  As described above, when load balancing is necessary in a specific frequency band, the base station device performs load balancing index indicating execution of load balancing and mobile station device that performs load balancing for a mobile station device in a standby state. Therefore, it is not necessary to add a dedicated message for load balancing control, and radio resource consumption can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (13) Also, in the base station apparatus of the present invention, when the load balance is necessary, paging in which a frequency priority indicating a priority order for each frequency band is set is transmitted to the mobile station apparatus. It is characterized by.

  In this way, when load balancing is necessary, the base station device transmits paging with frequency priority indicating the order of priority for each frequency band to the mobile station device, so the mobile station device Different frequencies that move due to cell reselection can be selected based on the frequency priority according to the load status for each frequency band, and efficient load balancing can be realized.

  (14) Further, the base station apparatus of the present invention is a base station apparatus that includes a mobile station apparatus and a base station apparatus, and performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus, A load balance determination unit that determines whether or not the load balance is necessary in a specific frequency band; and if the load balance is necessary as a result of the determination, the load balance is determined for the mobile station apparatus in a standby state. And a transmitter that transmits paging in which a load balance index indicating implementation is set.

  In this way, when load balancing is necessary, the base station device transmits paging with a load balancing index indicating execution of load balancing to the mobile station device in a standby state. It is no longer necessary to add a dedicated message, and radio resource consumption can be reduced. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  (15) A base station apparatus according to the present invention is a base station apparatus that includes a mobile station apparatus and a base station apparatus, and performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus, A load balance determination unit that determines whether or not the load balance is necessary in a specific frequency band; and if the load balance is necessary as a result of the determination, the load balance is determined for the mobile station apparatus in a standby state. A transmission unit configured to transmit a paging in which a load balance index indicating execution and a load balance coefficient indicating a ratio of mobile station apparatuses performing the load balance are set.

  As described above, when load balancing is required, the base station apparatus has a load balancing index indicating the load balancing and a load indicating the ratio of the mobile station apparatuses performing the load balancing with respect to the mobile station apparatuses in the standby state. Since paging with the balance factor set is transmitted, it is not necessary to add a dedicated message for load balancing control, and consumption of radio resources can be suppressed. In addition, since the base station device can notify the execution of control to a plurality of waiting mobile station devices by one paging, than the conventional method in which control is individually notified for each connected mobile station device Also, load balancing can be performed efficiently.

  Moreover, since the mobile station apparatus can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

  Further, since the base station device transmits paging with a load balancing coefficient indicating the proportion of mobile station devices that perform load balancing to the mobile station device that is waiting, a plurality of a predetermined proportion of standby The mobile station apparatus can be notified of the execution of control all at once by one paging, and the number of paging transmissions necessary for load balancing can be suppressed, so that the utilization efficiency of radio resources is improved. In addition, it is possible to shorten the time required to complete load balancing between frequency bands.

  As described above, according to the present invention, a communication system, mobile station apparatus, and base station apparatus capable of correcting the load balance between frequency bands and efficiently balancing the load between frequency bands. Can be provided.

It is a block diagram which shows an example of the base station apparatus which concerns on embodiment of this invention. It is a block diagram which shows an example of the mobile station apparatus which concerns on embodiment of this invention. It is the sequence chart which showed the outline of the load balancing method using paging which concerns on embodiment of this invention. It is an example of the flowchart for the mobile station apparatus which concerns on the 1st Embodiment of this invention to judge whether load balance control is required in the reception process of paging. FIG. 5 is an example of a flowchart illustrating load balancing control of a mobile station apparatus that is determined to require load balancing control in FIG. 4 in the first embodiment of the present invention. It is an example of the flowchart for the mobile station apparatus which concerns on the 2nd Embodiment of this invention to judge whether load balance control is required in the receiving process of paging. FIG. 9 is an example of a flowchart illustrating load balancing control of a mobile station apparatus that is determined to require load balancing control in FIG. 6 in the second embodiment of the present invention. It is an example of the sequence chart in connection with the cell reselection in EUTRA. It is the flowchart shown about an example of the method of the same frequency (Intra-frequency) cell reselection. 5 is a flowchart illustrating an example of a method for re-selecting an inter-frequency cell.

  Before describing an embodiment of the present invention, a physical channel and cell reselection method according to the present invention will be briefly described.

(1) Physical Channel A physical channel (or physical signal) used in EUTRA and Advanced EUTRA will be described. The physical channel may be added or changed in the future in EUTRA and Advanced EUTRA, but even if it is changed, the description of each embodiment of the present invention is not affected.

  Synchronization signals (Synchronization Signals) are composed of three types of primary synchronization signals and secondary synchronization signals composed of 31 types of codes arranged alternately in the frequency domain. Depending on the combination, 504 cell identifiers (cell IDs) for identifying the base station apparatus and frame timing for radio synchronization are shown. The mobile station device specifies the cell ID of the synchronization signal received by the cell search.

  A physical broadcast information channel (PBCH; Physical Broadcast Channel) is transmitted for the purpose of notifying control parameters (broadcast information (system information): System information) that are commonly used by mobile station apparatuses in a cell. Broadcast information that is not notified by the physical broadcast information channel is transmitted by a layer 3 message using the downlink data channel, in which radio resources are notified by the downlink control channel. As broadcast information, access restriction information, a cell global ID (CGI) indicating an individual identifier of a cell, and the like are notified.

  The downlink reference signal is a pilot signal transmitted at a predetermined power for each cell. The downlink reference signal is a known signal that is periodically repeated at a frequency / time position based on a predetermined rule. The mobile station apparatus measures the reception quality for each cell by receiving the downlink reference signal. The mobile station apparatus also uses the downlink reference signal as a reference signal for demodulation of the downlink control channel or downlink data channel transmitted simultaneously with the downlink reference signal. The sequence used for the downlink reference signal is a sequence that can be uniquely identified for each cell. In addition, although a downlink reference signal may be described as cell-specific RS (Cell-specific reference signals), the use and meaning are the same.

  A downlink control channel (PDCCH: Physical Downlink Control Channel) is transmitted in some OFDM symbols from the beginning of each subframe, and radio resource allocation information according to the scheduling of the base station apparatus is transmitted to the mobile station apparatus. Used to indicate the amount of power increase / decrease adjustment. The mobile station apparatus receives a downlink control channel before transmitting and receiving downlink data and layer 3 messages (paging, handover command, etc.), and transmits radio resource allocation information called an uplink grant at the time of transmission and a downlink grant at the time of reception. Need to get.

  A downlink data channel (PDSCH; Physical Downlink Shared Channel) is used to notify paging and broadcast information as a layer 3 message in addition to downlink data. The radio resource allocation information of the downlink data channel is indicated by the downlink control channel.

  The uplink data channel (PUSCH: Physical Uplink Shared Channel) mainly transmits uplink data, and can include control data such as downlink reception quality and ACK / NACK. Similarly to the downlink, the radio resource allocation information of the uplink data channel is indicated by the downlink control channel.

  A random access channel (PRACH; Physical Random Access Channel) is a channel used to notify a preamble sequence and has a guard time. The random access channel is used as an access procedure to the base station apparatus by an asynchronous mobile station apparatus whose uplink transmission timing is not synchronized with the base station apparatus, and is used for adjusting a radio resource request and uplink transmission timing. Since other physical channels are not related to each embodiment of the present invention, detailed description thereof is omitted.

(2) Cell Reselection Method FIG. 8 is an example of a sequence chart related to cell reselection in a mobile station apparatus of EUTRA. Cell reselection is performed when the mobile station apparatus 1 is in a non-radio resource control connection state (RRC_Idle) in a standby state (waiting). A cell is an area where the base station device 3 and the mobile station device 1 can communicate, and is distinguished by a frequency and a cell ID. The frequency is represented by an absolute radio frequency channel number (ARFCN). FIG. 8 shows a case where a plurality of base station devices 3 that transmit a mobile station device 1 and a downlink reference signal that can be received by the mobile station device 1 are arranged (in the example of FIG. 8, the base station device 3A, the base station The apparatus 3B) starts from a state in which the mobile station apparatus 1 determines that the reception quality of the downlink reference signal of the base station apparatus 3A is the best by cell search. The mobile station apparatus 1 receives broadcast information from the base station apparatus 3A and determines whether camping is possible (step S101). If it is possible to camp, camp on the base station device 3A (step S102). The process up to step S102 is called cell selection. Here, camping on the base station device 3A indicates that the mobile station device 1 is in a standby state in the cell of the frequency band transmitted by the base station device 3A.

  Moreover, the mobile station apparatus 1 receives parameters necessary for cell reselection from the broadcast information. As parameters notified by broadcast information, there are a frequency priority indicating the order of priority for each frequency band, an offset value applied to the reception quality of the cell, a timer indicating a time required for establishment of cell reselection, and the like. Then, the reception quality of the downlink reference signal between the base station device 3A and the base station device 3B is compared based on the received broadcast information (step S103A, step S103B). When the reception quality of the downlink reference signal of the base station device 3B exceeds the reception quality of the downlink reference signal of the base station device 3A for a predetermined time, the mobile station device 1 determines that cell reselection has been established ( In step S104, the camping destination is changed from the base station device 3A to the base station device 3B (step S105). And the broadcast information of base station apparatus 3B is received, and cell reselection is completed (step S106).

  The reception quality is obtained by the mobile station apparatus 1 measuring the reference signal received power (RSRP) or reference signal received quality (RSRQ) of each downlink reference signal. Note that the base station device 3A and the base station device 3B are not different base station devices 3, but may be different transmission devices (cells with the same frequency or cells with different frequencies) of the same base station device 3.

  FIG. 9 is a flowchart illustrating an example of a method of re-selecting the same frequency (Intra-frequency) cell. In FIG. 9, the mobile station apparatus 1 measures the reception quality of the serving cell that is the camping destination cell, and determines whether or not the receiving quality of the serving cell is equal to or less than the threshold (step S201). If it is not less than or equal to the threshold value, the mobile station device 1 ends the cell reselection. When it is below the threshold value, the mobile station apparatus 1 performs cell ranking, which is the ordering of the cells being measured (step S202). Cell ranking adds the offset value acquired from broadcast information to the reception quality of the serving cell and neighboring cells other than the serving cell, and calculates the ranking reference value for each cell used for ranking. That is. Subsequently, the mobile station device 1 compares the ranking reference value of the neighboring cell and the serving cell, and uses a timer indicating the required time when the ranking reference value of the serving cell falls below the ranking reference value of the neighboring cell. If it is too short, the cell reselection is terminated. The mobile station apparatus 1 determines that the cell reselection condition is satisfied when the ranking reference value of the serving cell is lower than the ranking reference value of the neighboring cell is longer than the timer indicating the required time (step S203). ), The same frequency cell is reselected (step S204).

  FIG. 10 is a flowchart illustrating an example of an inter-frequency cell reselection method. In FIG. 10, the mobile station apparatus 1 has a frequency band in which a higher priority than the priority (frequency priority) set in the frequency band of the serving cell that is the camping destination cell exists. Whether or not is determined from the notification information (step S301). When there is no frequency band with high priority, the mobile station apparatus 1 ends cell reselection. When there is a frequency band with high priority, the mobile station apparatus 1 measures the reception quality of the serving cell and determines whether the reception quality of the serving cell is equal to or less than the threshold (step S302). If it is not less than or equal to the threshold value, the mobile station apparatus 1 ends the cell reselection. When it is equal to or lower than the threshold, the mobile station device 1 compares the reception quality of the neighboring cell in the frequency band with high priority and the serving cell, and the reception quality of the serving cell is in the neighboring cell having the frequency band with high priority When the time lower than the reception quality is longer than the timer indicating the required time, the cell reselection is terminated (step S303). The mobile station apparatus 1 satisfies the cell reselection condition when the reception quality of the serving cell is lower than the reception quality of a neighboring cell having a high priority frequency band and is longer than the timer indicating the required time. (Step S303), and reselection of a different frequency cell is performed (Step S304). Note that the flowchart of FIG. 10 is also applied to inter-system (Inter-RAT) cell reselection.

  Considering the above matters, preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the present invention, detailed descriptions of known functions and configurations related to the present invention will be omitted if it is determined that the gist of the present invention will be obscured.

<First Embodiment>
A first embodiment of the present invention will be described below. The present embodiment relates to a method in which the base station apparatus 3 notifies the mobile station apparatus 1 of execution of load balancing using paging.

  FIG. 1 is a block diagram illustrating an example of a base station apparatus 3 according to an embodiment of the present invention. The base station apparatus 3 includes a reception unit 101, a demodulation unit 103, a decoding unit 105, an upper layer 107, an encoding unit 109, a modulation unit 111, an RS generation unit 113, a multiplexing unit 115, a transmission unit 117, a control unit 119, a load balancer. The determination unit 121 is configured.

  The upper layer 107 inputs downlink data and downlink control data to the encoding unit 109. The encoding unit 109 encodes each input data and inputs the encoded data to the modulation unit 111. Modulator 111 modulates the encoded signal. Further, the signal output from the modulation unit 111 and the downlink reference signal generated by the RS generation unit 113 are mapped to the frequency domain by the multiplexing unit 115. An output signal from the multiplexing unit 115 is input to the transmission unit 117. The transmission unit 117 converts the frequency domain signal into a time domain signal, places the converted signal on a carrier having a predetermined frequency, performs power amplification, and transmits the signal. In addition, load information for each frequency band is input from the upper layer 107 to the load balance determination unit 121. When the load balance determination unit 121 determines that load balancing is necessary in one or a plurality of frequency bands from the load information for each frequency band, the load balance determination unit 121 generates data necessary for creating paging for notifying load balance, Input to the unit 109. The load balance determination unit 121 may be realized as a sub-block of the upper layer 107. A downlink data channel in which downlink control data is arranged typically constitutes a layer 3 message (RRC message).

  The receiving unit 101 converts a signal received from the mobile station device 1 into a baseband digital signal. The digital signal is input to the demodulator 103 and demodulated. The signal demodulated by the demodulation unit 103 is then input to the decoding unit 105 and decoded, and the correctly decoded uplink control data and uplink data are output to the upper layer 107. Control information necessary for the control of each block is input from the upper layer 107 to the control unit 119, and control information related to transmission from the control unit 119 is transmitted as transmission control information as an encoding unit 109, a modulation unit 111, and an RS generation unit. Control information related to reception is appropriately input to each block of the reception unit 101, demodulation unit 103, and decoding unit 105 as reception control information in each block of 113, multiplexing unit 115, and transmission unit 117. In FIG. 1, the other constituent elements of the base station apparatus 3 are omitted because they are not related to the present embodiment.

  FIG. 2 is a block diagram showing an example of the mobile station apparatus 1 according to the embodiment of the present invention. The mobile station apparatus 1 includes a reception unit 201, a demodulation unit 203, a decoding unit 205, a measurement processing unit 207, a cell selection unit 209, a random access generation unit 211, an encoding unit 213, a modulation unit 215, a transmission unit 217, and a transmission band setting. Part 219, control part 221, and upper layer 223. Prior to reception, control information is input from the upper layer 223 to the control unit 221, and control information related to reception is appropriately input to the reception unit 201, the demodulation unit 203, and the decoding unit 205 as reception control information. The reception control information includes information such as reception timing, multiplexing method, and radio resource arrangement information regarding each channel in addition to information on the reception frequency band.

  The reception signal is received by the reception unit 201. The receiving unit 201 receives a signal in the frequency band notified by the reception control information. The received signal is input to the demodulation unit 203. Demodulation section 203 demodulates the received signal, inputs a signal to decoding section 205 to correctly decode downlink data and downlink control data, and inputs each decoded data to higher layer 223. The decoding unit 205 has a paging processing unit as a sub-block (not shown). When the decoded data is paging, the paging processing unit appropriately processes the data based on the control content instructed by paging. If the information set for paging is load balancing, the paging processing unit notifies the cell selection unit 209 of the start of load balancing. In the case of paging other than load balancing (notification information change notification, disaster information notification, call notification), the paging processing unit notifies the upper layer 223 of the corresponding instruction content. The measurement processing unit 207 performs measurement processing based on the measurement results of the downlink reference signal reception quality for each cell and the measurement results of the reception error rate of the downlink control channel or the downlink data channel, and the measured reception quality is measured. Measurement information averaged (filtered) for each sample is generated, and the measurement information is output to the upper layer 223 and the cell selection unit 209 as necessary.

  The cell selection unit 209 operates when the mobile station apparatus 1 is in the non-radio resource control connection (RRC_Idle) mode, and is optimal based on parameters necessary for cell selection (cell reselection) and measurement information measured by the measurement processing unit 207. The correct cell. The cell selection unit 209 further includes a priority management unit that manages priority for each frequency band and a cell quality comparison unit that compares reception quality between cells (not shown). The cell selection (cell reselection) method performed by the cell selection unit 209 uses the method shown in FIG. 9 or FIG. 10, respectively. Note that the cell selection unit 209 may be realized as a sub-block of the upper layer 223.

  Prior to transmission, control information is input from the upper layer 223 to the control unit 221, and control information related to transmission is transmitted to the random access generation unit 211, the encoding unit 213, the modulation unit 215, and the transmission band setting unit 219. Entered appropriately. The transmission control information includes information such as encoding information, modulation information, transmission frequency band information, transmission timing for each channel, multiplexing method, and radio resource arrangement information as uplink scheduling information of the transmission signal. The random access information is input to the random access generation unit 211, and the random access generation unit 211 generates random access data. The random access information includes preamble information, radio resource information for transmission, and the like. In addition to the random access data, uplink data and uplink control data are input to the encoding unit 213 from the upper layer 223. The encoding unit 213 appropriately encodes each data according to the transmission control information, and outputs the data to the modulation unit 215. The modulation unit 215 modulates the input from the encoding unit 213.

  The transmission band setting unit 219 sets a frequency band to be transmitted to each transmission unit. The transmission unit maps the output of the modulation unit 215 to the frequency domain, converts the frequency domain signal into a time domain signal, performs power amplification on a carrier wave of a predetermined frequency, and transmits the signal. The event information input to the upper layer 223 is input as uplink data to the encoding unit 213 and the modulation unit 215, and is appropriately arranged in the uplink data channel and transmitted as a transmission signal. The uplink data channel in which the uplink control data is arranged typically constitutes a layer 3 message (RRC message). In FIG. 2, the other components of the mobile station apparatus 1 are omitted because they are not related to this embodiment.

  FIG. 3 is a sequence chart showing an outline of a load balancing method using paging according to the embodiment of the present invention. The mobile station apparatus 1 receives broadcast information from the base station apparatus 3A selected by cell selection (or cell reselection) (step S401). If the mobile station apparatus 1 determines that camping is possible based on the broadcast information, the mobile station apparatus 1 sets other broadcast information parameters and camps on the base station apparatus 3A (step S402). That is, the mobile station device 1 enters a standby state (RRC_Idle) in the cell of the frequency band transmitted by the base station device 3A. The mobile station device 1 in the standby state receives paging transmitted from the base station device 3A at a predetermined period based on the broadcast information.

  The cycle in which paging is transmitted is based on the EUTRA paging specification (Non-Patent Document 2). Paging is a layer 3 message (RRC message) and is transmitted on the downlink data channel indicated by the radio resource allocation information notified by the downlink grant of the downlink control channel. A CRC (Cyclic Redundancy Check) of a downlink control channel that notifies a downlink grant indicating transmission of paging is scrambled by a paging identifier (P-RNTI; Paging-Radio Network Temporary Identifier). To be scrambled is typically to perform exclusive OR for each bit. The mobile station apparatus 1 descrambles the CRC of the downlink control channel with the P-RNTI, and receives the paging based on the downlink ring run when the correct CRC is obtained.

  Returning to FIG. 3, the base station device 3A acquires load information from another base station device 3 or an upper control station (step S403). The load information indicates how much load is applied for each frequency band. The load information for each frequency band may be notified from other base station apparatuses 3 by communication between base station apparatuses 3, or a higher-level control station (for example, MME (Mobility Management Entity) that manages a plurality of base station apparatuses 3 ) May be notified. Load information for each frequency band is generated based on the consumption of radio resources for each frequency band or the number of connections of the mobile station apparatus 1 for each frequency band. Note that the load information for each frequency band may be shown by being divided into a plurality of levels and encoded into several bits, or a method showing the actual load as a percentage. It may be 1-bit information indicating whether or not the frequency requires load balancing.

  The base station apparatus 3A uses a load balancing indicator (Load balancing indicator) in data set for paging in order to move a part of the mobile station apparatus 1 in a frequency band that requires load balancing to a cell in another frequency band. Set and transmit (step S404). Prior to the transmission of paging, the base station device 3A transmits a downlink control channel (not shown) to notify downlink radio resource information to which paging is transmitted. The procedure for the mobile station apparatus 1 to receive the paging may be the same as EUTRA. The load balance index may be 1-bit information indicating whether load balance is necessary. The load balance indicator is set together with C-RNTI (Cell-RNTI) which is an intra-cell identifier set for each mobile station apparatus 1 in the paging message.

  The base station apparatus 3A may transmit the C-RNTIs of a plurality of mobile station apparatuses 1 set to paging (for example, EUTRA can include a maximum of 16 C-RNTIs). The base station device 3A may transmit the load balancing control effective time timer set to paging. The base station device 3A may set the offset value for load balancing to paging and transmit it. The effective time timer for load balance control and the offset value for load balance may be transmitted as broadcast information. The base station apparatus 3A selects an appropriate number of mobile station apparatuses 1 to be moved to a cell of another frequency band by C-RNTI of the mobile station apparatus 1 set together with the load balance index, that is, load balancing, based on the load information. To do. The base station device 3A may set and transmit a load balance index for a plurality of pagings until determining that load balance is unnecessary.

  The mobile station apparatus 1 performs paging reception processing, and when paging includes a load balance index, performs load balance control and autonomously tries to move to another frequency band with a low load (step S405). . A specific method of load balance control performed by the mobile station apparatus 1 will be described with reference to FIG. Note that the base station device 3 uses paging to notify the necessity of load balancing control is limited to the mobile station device 1 that is waiting (RRC_Idle), and has no effect on the mobile station device 1 that is connected (RRC_Connected). Note that. The connected mobile station apparatus 1 does nothing even when receiving the paging with the load balance index set. In the load balance control for the connected mobile station device 1, the base station device 3 releases the radio resource control connection or instructs a different frequency handover to notify the frequency priority used for cell reselection as in the conventional case. It is realized by doing.

  FIG. 4 is an example of a flowchart for the mobile station apparatus 1 according to the first embodiment of the present invention to determine whether or not load balancing control is necessary in the paging reception process. The waiting mobile station apparatus 1 receives paging at the paging reception timing. If no load balance index is set for the received paging (step S501), processing of other data notified by paging is performed (step S502). Other data processing includes notification information change notification, disaster information notification, and call notification.

  When the load balance index has been set (step S501), the mobile station apparatus 1 determines whether the C-RNTI of the local station is included in the paging (step S503). If the C-RNTI of its own station is not included, the mobile station device 1 determines that it has not been selected as the load balancing target mobile station device 1 and ends the process. When the C-RNTI of its own station is included, the mobile station device 1 determines that load balancing control is necessary (step S504), and ends the process. Note that if a process for confirming whether or not the load balance index is transmitted and whether or not load balance control is necessary is included as part of the paging reception process, a flowchart other than that shown in FIG. 4 may be adopted. good. For example, when the load balance index is set, the mobile station apparatus 1 may determine that load balance control is necessary without determining whether the C-RNTI of the local station is included in paging.

  In addition, it is also possible to scramble the CRC of the downlink control channel using a special identifier indicating execution of load balancing instead of P-RNTI. For example, an identifier (LB-RNTI (Load Balancing-RNTI)) that is fixed in the communication system and has the same bit length as the CRC is set, and the CRC of the downlink control channel that notifies load balancing is scrambled by LB-RNTI. It is also possible to transmit. The mobile station device 1 attempts to receive the downlink control channel by descrambling the CRC of the downlink control channel with LB-RNTI. When the downlink control channel descrambled by LB-RNTI can be correctly received, the mobile station apparatus 1 does not need to determine whether or not the load balance index shown in FIG. 4 is set, and further, the C-RNTI of the own station is used for paging. It may be determined that the load balance control is necessary without determining whether or not it is included.

  FIG. 5 is an example of a flowchart illustrating the load balance control of the mobile station apparatus 1 that is determined to require the load balance control in FIG. 4 in the first embodiment of the present invention. As a load balancing control, the mobile station apparatus 1 determines the priority (frequency priority) set for the frequency band in which it is waiting, that is, the camping frequency, regardless of the value notified by the broadcast information. It is considered that the value has been changed to the lowest value (step S601). The priority of the frequency band other than the serving frequency is not changed. When the offset value for load balancing is set, the mobile station device 1 applies the offset value set for the reception quality of the serving cell, or a neighboring cell of a different frequency other than the serving cell Apply the offset value set for. Typically, the offset value applied to the serving cell is a negative value, and the offset value applied to the neighboring cell having a different frequency is a positive value. The offset value applied to the neighboring cells of different frequencies may be prepared for each frequency.

  By performing this control, the mobile station device 1 is likely to cause reselection of different frequency cells for neighboring cells of different frequencies having a higher priority than the serving frequency. The mobile station apparatus 1 cancels the change of the priority of the serving frequency and the application of the offset value when cell reselection is performed or when a predetermined time has elapsed. The predetermined time may be notified by broadcast information, may be uniquely determined in the communication system, or may be notified of an effective time timer indicating the execution time of load balancing control by paging. When the effective time timer of the load balancing control is notified, the mobile station device 1 activates the effective time timer, changes the priority of the serving frequency within the time when the effective time timer is counted, and sets the offset value. Apply and if the valid time timer expires, apply the original value again.

  As described above, in the first embodiment, the base station apparatus 3 notifies the execution of the load balance control using paging to one or more mobile station apparatuses 1 that are camped in the frequency band that requires load balance. To do. The mobile station apparatus 1 determines whether or not the load balance control is performed according to the contents of paging, and when the execution of the load balance control is notified, sets the priority of the serving frequency to the lowest value. By using this control, it is possible to achieve load balancing between frequency bands.

  As described above, since the base station apparatus 3 can notify the mobile station apparatus 1 of the execution of load balancing control using paging, there is no need to add a dedicated message for load balancing control. Resource consumption can be reduced. In addition, since the base station apparatus 3 can notify the execution of control to a plurality of waiting mobile station apparatuses 1 by one paging, the control has been individually notified for each connected mobile station apparatus 1. It becomes possible to implement load balancing more efficiently than the above method. Moreover, since the mobile station apparatus 1 can divert the paging reception procedure, it is possible to suppress power consumption associated with unnecessary reception control. Moreover, since the mobile station apparatus 1 can divert the conventional cell reselection method, the addition of a function is unnecessary for realization, and the control becomes simple. Moreover, since the load balance is corrected by balancing the load between the frequency bands, it is possible to effectively use radio resources and improve the throughput. Further, by balancing the load between the frequency bands, the amount of interference between cells is also balanced, so that communication quality is improved.

<Second Embodiment>
A second embodiment of the present invention will be described below. The present embodiment relates to a method in which the base station device 3 notifies paging to the mobile station devices 1 having an arbitrary ratio of execution of load balancing.

  Since the configurations of the base station device 3 and the mobile station device 1 of the present embodiment may be the same as those of the first embodiment, description thereof is omitted. However, the load balance determination unit 121 of the base station apparatus 3 has a function of setting a load balance coefficient indicating the ratio of the mobile station apparatus 1 that performs load balance control to paging. In addition, the base station apparatus 3 may generate the value of the load balance coefficient in the load balance determination unit 121, or the value notified from another station (another base station apparatus 3 or a higher control station) as it is. May be used. Further, the paging processing unit of the mobile station apparatus 1 has a function of acquiring a load balance coefficient from paging and notifying the cell selection unit 209. The cell selection unit 209 of the mobile station device 1 has a function of performing cell reselection for load balancing based on the load balancing coefficient. The sequence chart relating to the load balancing method may be the same as that in FIG. 3, except that C-RNTI is not set in the paging message, and a load balancing index and a load balancing coefficient described later are set instead. Note that the base station apparatus 3 can also indicate to the mobile station apparatus 1 that load balancing is performed by setting only the load balancing coefficient without including the load balancing index in the paging message.

  FIG. 6 is an example of a flowchart for the mobile station apparatus 1 according to the second embodiment of the present invention to determine whether or not load balancing control is necessary in the paging reception process. The waiting mobile station apparatus 1 receives paging at the paging reception timing. If no load balance index is set for the received paging (step S701), the mobile station apparatus 1 processes other data notified by paging (step S702). Other data processing includes notification information change notification, disaster information notification, and call notification. When the load balance index is set, the mobile station apparatus 1 receives the load balance coefficient included in the paging (step S703), determines that load balance control is necessary (step S704), and ends the process.

  Here, the load balance coefficient is a parameter that indicates how many mobile station apparatuses 1 among the mobile station apparatuses 1 that have received the paging for load balance actually perform load balance control. That is, the base station apparatus 3A adaptively controls the number of mobile station apparatuses 1 to be moved to different frequencies according to the number of mobile station apparatuses 1 determined to require load balance control by using a load balance coefficient. It becomes possible. As the load balance coefficient, an appropriate number is preferably defined in advance from a numerical value of 0 to 100 (for example, 10, 20, 30,..., 100), and one of them is selected by the base station apparatus 3A. The mobile station apparatus 1 is notified using paging. For example, when the number of mobile station devices 1 in the serving frequency is 1000 and 300 of them are to be moved to different frequencies, the base station device 3A may select 30 as the load balance coefficient. Note that a flowchart other than that shown in FIG. 6 may be adopted as long as the process of confirming whether or not the load balance index is transmitted and receiving the load balance coefficient is included as part of the paging reception process. .

  Note that, as described in the first embodiment, the base station device 3 can also scramble the CRC of the downlink control channel that notifies the load balance with the LB-RNTI and transmit it. In addition, when the base station device 3 does not transmit the load balance index, the mobile station device 1 identifies normal paging and paging for load balance control depending on the presence or absence of the load balance coefficient, and appropriately switches the reception processing. Is possible.

  FIG. 7 is an example of a flowchart illustrating the load balance control of the mobile station apparatus 1 that is determined to require the load balance control in FIG. 6 in the second embodiment of the present invention. First, the mobile station apparatus 1 selects a value (random value) from 0 to 100 (step S801). It is desirable that the selected random values follow a uniform distribution. Then, the mobile station apparatus 1 compares the magnitude relationship between the random value and the load balance coefficient received by paging (step S802). If the random value is smaller than the load balance coefficient, the mobile station device 1 does nothing and ends the load balance control. If the random value is larger than the load balance coefficient, the mobile station apparatus 1 determines that load balance control is necessary, and performs load balance control (step S803). The determination of the magnitude relationship between the random value and the load balance coefficient may be reversed. The method of load balance control performed by the mobile station apparatus 1 may be the same as the method shown in the description of FIG. Note that the load balance coefficient and the random value are not limited to a value of 0 to 100 (for example, a range of 0 to 1 may be used) as long as possible ranges coincide with each other.

  Also, the mobile station apparatus 1 can use load balance control that uses an initial value (default value) when a load balance coefficient is not set for paging. The initial value can be specified in advance by the base station device 3 using broadcast information. The mobile station apparatus 1 can also use load balance control that uses the same value as the previous time when the load balance coefficient is not set for paging.

  As described above, in the second embodiment, the base station apparatus 3 notifies paging to the implementation of the load balancing control to any proportion of the mobile station apparatuses 1 that are camping in the frequency band that requires load balancing. To do. The mobile station apparatus 1 determines whether or not to perform load balance control based on a load balance coefficient included in paging and a random value selected by the own station. Set to the lowest value. By using this control, it is possible to achieve load balancing between frequency bands.

  As described above, in addition to the effects of the first embodiment, the base station apparatus 3 can simultaneously notify the execution of control by a single paging to a plurality of mobile station apparatuses 1 in a predetermined proportion of standby. Thus, load balancing can be performed more efficiently than the conventional method in which control is individually notified to each connected mobile station apparatus 1. That is, since the number of paging transmissions necessary for load balancing can be suppressed, the utilization efficiency of radio resources is improved. In addition, it is possible to shorten the time required to complete load balancing between frequency bands.

<Third Embodiment>
A third embodiment of the present invention will be described below. The present embodiment is a modification of the first or second embodiment, in which the base station device 3 notifies the mobile station device 1 of the implementation of load balancing using paging, and further performs load balancing. The present invention relates to a method for setting a priority for each frequency band applied to the mobile station apparatus 1. Note that the priority for each frequency band includes the meaning of the priority set for a different system (Inter-RAT).

  Since the configurations of the base station device 3 and the mobile station device 1 of the present embodiment may be the same as those of the first embodiment or the second embodiment, description thereof is omitted. However, the load balance determination unit 121 of the base station device 3 has a function of setting the priority for each frequency band applied to the mobile station device 1 that performs load balance control to paging. Note that the base station apparatus 3 may generate a priority (frequency priority) for each frequency band by the load balance determination unit 121, or from another station (another base station apparatus 3 or a higher-level control station). The notified frequency priority may be used as it is. Further, the paging processing unit of the mobile station apparatus 1 has a function of acquiring the priority for each frequency band from paging and notifying the cell selection unit 209. The cell selection unit 209 of the mobile station apparatus 1 has a function of performing cell reselection for load balancing based on the set priority for each frequency band. The sequence chart regarding the load balancing method may be the same as that in FIG. 3, but the specific control method of the base station apparatus 3A and the mobile station apparatus 1 is based on the description of either the first embodiment or the second embodiment. Note that this is done.

  Furthermore, the base station apparatus 3 of this embodiment sets the priority for every frequency band appropriately according to the load condition for every frequency band. That is, the frequency priority of a frequency with a high load other than the located frequency is set low, and the frequency priority of a frequency with a low load other than the located frequency is set high. Similarly to the first embodiment or the second embodiment, the base station apparatus 3 sets both or one of the effective time timer for load balancing control and the offset value for load balancing to paging and transmits the paging. Alternatively, it may be transmitted as broadcast information.

  The mobile station apparatus 1 of the present embodiment determines whether or not load balance control is necessary based on the paging reception process of the first embodiment or the second embodiment, and determines that load balance control is necessary. The priority for each band is changed to a new frequency priority set for paging regardless of the value notified by the broadcast information. The frequency priority of the serving frequency may be set to paging or may not be set. When the frequency priority of the serving frequency is not set to paging, the mobile station device 1 may apply the value notified by the broadcast information without changing it, or change it to the lowest value and apply it. You may do it. There may be a frequency band in which frequency priority is not set by paging. Since the control method when the offset value for load balancing and the effective time timer for load balancing control are set has been described in the first embodiment or the second embodiment, description thereof will be omitted. The mobile station device 1 cancels the change of the priority for each frequency band when the effective time timer of the load balance control expires, and applies the original value.

  Thus, in the third embodiment, the base station apparatus 3 performs load balancing control that can be adjusted for each frequency band using paging for the mobile station apparatus 1 that is camping in a frequency band that requires load balancing. Notify implementation. The mobile station apparatus 1 determines whether or not the load balance control is performed based on the contents of paging. When performing the load balance control, the mobile station apparatus 1 changes the priority of the set frequency band as the load balance control. By using this control, it is possible to achieve load balancing between frequency bands.

  As described above, the base station device 3 notifies the mobile station device 1 that the load balancing control is performed using paging, and appropriately sets the frequency priority according to the load status for each frequency band. Since the mobile station apparatus 1 can adaptively control different frequencies that are moved by cell reselection, efficient load balancing can be realized.

  The embodiment described above is merely an example, and can be realized using various modifications and replacement examples. For convenience of explanation, the mobile station device 1 and the base station device 3 of the embodiment have been described using functional block diagrams. However, the functions of each part of the mobile station device 1 and the base station device 3 or some of these functions are described. A program for realization is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to control the mobile station apparatus 1 and the base station apparatus 3. Also good. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Further, the “computer-readable recording medium” dynamically holds a program for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, it is also assumed that a server that holds a program for a certain time, such as a volatile memory inside a computer system that serves as a server or client. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  Each functional block used in each of the above embodiments may be realized as an LSI that is typically an integrated circuit. Each functional block may be individually formed into chips, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and the design and the like within the scope of the present invention are also within the scope of the claims. include. For example, paging indicating that the load balancing is performed to the mobile station apparatus 1 may be generated by the determination of a higher control station (for example, MME) that manages the base station apparatus 3 instead of the base station apparatus 3. In this case, when it is determined that load balancing needs to be performed, the upper control station generates paging indicating that additional balancing is performed for the mobile station device 1 and transmits the paging to the base station device 3, and the base station device 3 It may be designed such that the transmission timing of paging indicating the execution of the received load balancing is adjusted so as to coincide with the reception timing of the mobile station apparatus 1 and transmitted.

DESCRIPTION OF SYMBOLS 1 Mobile station apparatus 3, 3A, 3B Base station apparatus 101 Reception part 103 Demodulation part 105 Decoding part 107 Upper layer 109 Encoding part 111 Modulation part 113 RS generation part 115 Multiplexer 117 Transmission part 119 Control part 121 Load balance judgment part 201 Reception Unit 203 demodulation unit 205 decoding unit 207 measurement processing unit 209 cell selection unit 211 random access generation unit 213 encoding unit 215 modulation unit 217 transmission unit 219 transmission band setting unit 221 control unit 223 upper layer

Claims (15)

A communication system comprising a mobile station device and a base station device, and performing load balancing for distributing a load for each frequency band allocated to the mobile station device,
When the load balancing is necessary in a specific frequency band, the base station device transmits a paging in which a load balancing index indicating execution of the load balancing is set to a mobile station device in a standby state,
When the load balancing index is set in the received paging, the mobile station apparatus in the standby state resets a parameter necessary for performing cell reselection, and uses the reset parameter to A communication system characterized by executing reselection. A communication system comprising a mobile station device and a base station device, and performing load balancing for distributing a load for each frequency band allocated to the mobile station device,
When the load balancing is necessary in a specific frequency band, the base station device performs a load balancing index indicating the implementation of the load balancing and the mobile station device performing the load balancing for a mobile station device in a standby state. Send a paging with a load balancing factor that indicates the percentage of
The mobile station apparatus in the standby state compares the load balance coefficient with a randomly selected value when the load balance index and the load balance coefficient are set in the received paging, and based on the comparison result Then, a parameter necessary for executing cell reselection is reset, and cell reselection is executed using the reset parameter. The parameter includes a frequency priority indicating a priority of a serving frequency in which the mobile station device is located,
The mobile station apparatus performs cell reselection by resetting the frequency priority of a serving frequency notified by broadcast information from the base station apparatus to a lowest value. 2. The communication system according to 2. The parameter includes a frequency priority indicating an order of priority for each frequency band,
The mobile station apparatus resets the frequency priority indicated by the paging in place of the in-zone frequency notified by the broadcast information from the base station apparatus and the frequency priority of a different frequency different from the in-zone frequency. 3. The communication system according to claim 1, wherein cell reselection is performed. A mobile station apparatus comprising a mobile station apparatus and a base station apparatus, and applied to a communication system that performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
When the load balancing index indicating the execution of the load balancing is set in the paging received in the standby state, the parameters necessary for executing the cell reselection are reset, and the cell is set using the reset parameters. A mobile station apparatus that performs reselection. A mobile station apparatus comprising a mobile station apparatus and a base station apparatus, and applied to a communication system that performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
When a paging received in a standby state is set with a load balance index indicating the execution of the load balance and a load balance coefficient indicating the ratio of the mobile station apparatus performing the load balance, the value selected at random and the load A movement characterized by comparing with an equilibrium factor, resetting a parameter necessary for performing cell reselection based on the comparison result, and performing cell reselection using the reset parameter Station equipment. The parameter includes a frequency priority indicating a priority of a frequency in which the local station is located,
The mobile station apparatus according to claim 5 or 6, wherein cell reselection is performed by resetting a frequency priority of a serving frequency notified by broadcast information from the base station apparatus to a minimum value. . The parameter includes a frequency priority indicating an order of priority for each frequency band,
Perform cell reselection by resetting the frequency priority indicated by the paging instead of the frequency priority of the in-service frequency notified by the broadcast information from the base station apparatus and the frequency priority of a different frequency different from the in-service frequency. The mobile station apparatus according to claim 5 or 6, characterized in that: A mobile station apparatus comprising a mobile station apparatus and a base station apparatus, and applied to a communication system that performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
A receiving unit that receives paging from the base station device in a standby state;
If the received paging is set with a load balancing index indicating the implementation of the load balancing, parameters necessary for performing cell reselection are reset, and cell reselection is performed using the reset parameters. And a cell selection unit to be executed. A mobile station apparatus comprising a mobile station apparatus and a base station apparatus, and applied to a communication system that performs load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
A receiving unit that receives paging from the base station device in a standby state;
When the received paging is set with a load balance index indicating the execution of the load balance and a load balance coefficient indicating the ratio of the mobile station apparatuses performing the load balance, a randomly selected value and the load balance coefficient A cell selection unit that resets parameters necessary for executing cell reselection based on the comparison result and executes cell reselection using the reset parameters. A mobile station apparatus characterized by the above. A base station apparatus comprising a mobile station apparatus and a base station apparatus, and performing load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
When the load balance is necessary in a specific frequency band, the base station apparatus transmits a paging in which a load balance index indicating execution of the load balance is set to a mobile station apparatus in a standby state. A base station apparatus comprising a mobile station apparatus and a base station apparatus, and performing load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
When the load balance is necessary in a specific frequency band, the load balance index indicating the load balance index indicating the execution of the load balance and the ratio of the mobile station devices performing the load balance for the mobile station devices in the standby state A base station apparatus that transmits paging with a coefficient set.   13. The paging in which a frequency priority indicating an order of priority for each frequency band is transmitted to the mobile station apparatus when the load balancing is necessary. Base station device. A base station apparatus comprising a mobile station apparatus and a base station apparatus, and performing load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
A load balance determination unit for determining whether the load balance is necessary in a specific frequency band;
A transmission unit configured to transmit paging in which a load balance index indicating execution of the load balance is set to a mobile station apparatus in a standby state when load balance is necessary as a result of the determination; Base station equipment. A base station apparatus comprising a mobile station apparatus and a base station apparatus, and performing load balancing for distributing a load for each frequency band allocated to the mobile station apparatus,
A load balance determination unit for determining whether the load balance is necessary in a specific frequency band;
As a result of the determination, when load balancing is necessary, for a mobile station apparatus in a standby state, a load balancing index indicating execution of the load balancing and a load balancing coefficient indicating a ratio of the mobile station apparatuses performing the load balancing A base station apparatus, comprising: a transmission unit configured to transmit paging in which is set.

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