JP5635568B2 - COMMUNICATION SYSTEM, MOBILE STATION DEVICE, BASE STATION DEVICE, COMMUNICATION METHOD, AND INTEGRATED CIRCUIT - Google Patents

Description

  The present invention relates to a communication system in which a mobile station apparatus is connected to a base station apparatus using a plurality of frequency bands at the same time, and more particularly to an event determination method related to measurement of reception quality in a frequency band of the mobile station apparatus and the base station apparatus.

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 one of the standards development projects for communication networks, and Advanced EUTRA, which is a further development (Also called LTE-Advanced) is under investigation.

In Advanced EUTRA, Carrier Aggregation is a technology that enables higher-speed data transmission while maintaining compatibility with EUTRA.
Has been proposed (Non-Patent Document 1, Chapter 5). Carrier aggregation is a method in which a transmitter transmits a plurality of different frequency bands (Component Carrier (component carrier,
This is a technology that realizes wideband communication by transmitting data by carrier elements or element carriers)) and virtually considering a plurality of different frequency bands as one frequency band.

A mobile station apparatus in a connected state in a communication system measures the reception quality of a signal transmitted from the base station apparatus, and sequentially communicates to a base station apparatus having better quality than the currently connected base station apparatus. In order to switch, it is necessary to perform a handover procedure. Therefore, an advanced EUTRA mobile station apparatus (hereinafter simply referred to as a mobile station apparatus) needs to measure the reception qualities of a plurality of component carriers for handover and compare the reception qualities. In the handover, a predetermined event condition (Measurement Reporting Event (event trigger condition or measurement report condition)) and a parameter (Event Triggered reporting criteria (event trigger criterion)) used for the event condition are set in advance by the mobile station apparatus from the base station apparatus. When the mobile station apparatus determines whether or not the notified event condition is satisfied (event determination) and the mobile station apparatus determines that the event condition is satisfied as a result of the event determination, the event condition (For example, Non-Patent Document 2, Section 10.1.2) Event determination may be performed for each carrier element as described in Non-Patent Document 3. It is being considered.

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 TS36.300, V9.0.0 (2009-06), Overall discription; Stage2http: //www.3gpp.org/ftp/Specs/html-info/36300.htm R2-093108, Huawei, 3GPP TSG-RAN WG2 # 66, May 4-8, 2009, San Francisco, USA

When a mobile station apparatus measures a plurality of frequency bands in a conventionally known communication system, the purpose is regarded as a different frequency measurement for different frequency handover. However, in the case of Advanced EUTRA in which a base station apparatus and a mobile station apparatus can be connected using a plurality of frequency bands, even if the mobile station apparatus performs a plurality of frequency measurements, this is not necessarily a measurement for different frequency handover. Is not limited. In particular, the measurement for comparing the reception qualities between a plurality of frequency bands used for the connection between the mobile station apparatus and the advanced EUTRA base station apparatus (hereinafter simply referred to as a base station apparatus) In this case, the mobile station apparatus should not make an event determination related to handover. Thus, in a communication system in which a mobile station apparatus is connected to a base station apparatus using a plurality of frequency bands by carrier aggregation, it is necessary to consider a new event determination method different from the conventional one.

  The present invention has been made in view of the above problems, and an event related to measurement of reception quality of a frequency band in a communication system in which a mobile station apparatus is connected to a base station apparatus using a plurality of mutually different frequency bands at the same time. An object of the present invention is to provide a communication system, a mobile station apparatus, a base station apparatus, a communication method, and an integrated circuit that can efficiently determine the above.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the communication system according to the present invention is a communication system in which a base station apparatus and a mobile station apparatus perform communication using a plurality of carrier elements determined in mutually different frequency bands at the same time. An event condition for the mobile station apparatus to measure the reception quality of at least one of the carrier elements and a transmission unit for notifying the mobile station apparatus of a parameter used for determining whether or not the event condition is satisfied, The mobile station apparatus includes: a reception unit that receives the event condition and the parameter; a measurement processing unit that measures reception quality of at least one of the carrier elements; and a cell that determines whether to adjust the received parameter The event condition is set based on the determination unit and the received parameter or the adjusted parameter, and the set Characterized in that it comprises a determining event determination unit that determines whether vent condition is satisfied, the.

  Thus, it is determined whether or not to adjust the received parameter, and based on the received parameter or the parameter after adjustment, the event condition is set, and it is determined whether or not the set event condition is satisfied. The mobile station apparatus can perform event determination by setting event conditions for each carrier element being measured, and can perform efficient event determination. When the mobile station apparatus performs parameter adjustment, establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event information reports is suppressed, so that power consumption in the mobile station apparatus can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus is improved. Moreover, since the consumption of radio resources for reporting event information is suppressed, the utilization efficiency of radio resources is improved. Since the base station apparatus controls the handover based on the measurement report from the mobile station apparatus, complicated control is not required and scheduling complexity is reduced.

  (2) Moreover, in the communication system of the present invention, the cell determination unit, when a plurality of carrier elements whose reception quality is measured by the measurement processing unit are used for connection to the base station device, It is determined that the received parameter is adjusted.

  In this way, when a plurality of carrier elements for measuring reception quality are used for connection to the base station apparatus, the received parameters are adjusted, so that establishment of the event condition is suppressed in the carrier elements. become.

  (3) Moreover, in the communication system of the present invention, the cell determination unit includes a plurality of carrier elements whose reception quality is measured by the measurement processing unit, in a reference cell serving as a reference for measurement of reception quality in the measurement processing unit. If not, it is determined to adjust the received parameter.

  As described above, the received parameter is adjusted when the plurality of carrier elements for measuring the reception quality are not the reference cell serving as a reference for the measurement of the reception quality in the measurement processing unit. Therefore, the measurement method is performed by using the reference cell. And the complexity of control of the mobile station apparatus or base station apparatus can be reduced. Furthermore, establishment of the event condition is suppressed in the carrier element.

  (4) Further, in the communication system of the present invention, the event determination unit has a time required until the event condition is satisfied for a carrier element determined by the cell determination unit to adjust the received parameter. The received parameter is adjusted to be longer than before the received parameter is adjusted, and it is determined whether or not the set event condition is satisfied.

  In this way, it is determined whether the set event condition is satisfied by adjusting the received parameter so that the time required until the event condition is satisfied is longer than before adjustment of the received parameter. The establishment of the event condition is suppressed in the carrier element.

  (5) Moreover, in the communication system of the present invention, the event determination unit is configured to detect a carrier element that the cell determination unit determines to adjust the received parameter when the mobile station apparatus is moving at high speed. A scaling coefficient used for time adjustment until the event condition is satisfied is invalidated, and it is determined whether or not the set event condition is satisfied.

  In this way, for the carrier element determined to adjust the received parameter, the scaling factor used for time adjustment until the event condition is satisfied is invalidated, and it is determined whether or not the set event condition is satisfied. The establishment of the event condition is suppressed in the carrier element.

  (6) In the communication system of the present invention, the event determination unit receives the received signal so that the event condition is suppressed in a carrier element determined by the cell determination unit to adjust the received parameter. It is characterized by adjusting parameters.

  In this way, since the received parameters are adjusted so that the establishment of the event condition is suppressed in the carrier element that is determined to adjust the received parameter, unnecessary event conditions are not satisfied, and event information is reported. Since generation | occurrence | production is suppressed, the power consumption in a mobile station apparatus can be reduced.

  (7) Further, the communication system of the present invention is a communication system in which a base station apparatus and a mobile station apparatus perform communication by simultaneously using a plurality of carrier elements determined in mutually different frequency bands. The station apparatus transmits an event condition for the mobile station apparatus to measure the reception quality of at least one carrier element and a parameter used to determine whether or not the event condition is satisfied to the mobile station apparatus. The mobile station apparatus includes: a reception unit that receives the event condition and the parameter; a measurement processing unit that measures reception quality of at least one of the carrier elements; and whether or not the event condition is satisfied A cell determination unit that determines whether or not to perform the event, and the event condition is set based on the determination result of the cell determination unit, and the set event Conditions characterized in that and a determining event determination unit that determines whether satisfied.

  As described above, since it is determined whether or not the event condition is satisfied, the mobile station apparatus performs event determination by setting the event condition for each carrier element being measured. Event determination can be performed. When the mobile station apparatus does not perform event determination, establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event reports is suppressed, so that power consumption in the mobile station apparatus can be reduced. In addition, since the consumption of radio resources for event reporting is suppressed, the utilization efficiency of radio resources is improved. Moreover, since the base station apparatus can designate the presence / absence of event determination for each cell with respect to the mobile station apparatus, it is possible to perform flexible handover control in accordance with the actual arrangement of the base station apparatus.

  (8) Moreover, in the communication system of the present invention, the cell determination unit, when a plurality of carrier elements whose reception quality is measured by the measurement processing unit are used for connection to the base station device, It is characterized in that it is determined not to determine whether or not the event condition is satisfied.

  As described above, when a plurality of carrier elements for measuring the reception quality are used for connection to the base station apparatus, it is not determined whether or not the event condition is satisfied. It will be suppressed in the carrier element.

  (9) Moreover, in the communication system of the present invention, the cell determination unit includes a plurality of carrier elements whose reception quality is measured by the measurement processing unit in a reference cell serving as a reference for measurement of reception quality in the measurement processing unit. If not, it is determined not to determine whether or not the event condition is satisfied.

  As described above, when a plurality of carrier elements for measuring reception quality are not reference cells serving as a reference for measurement of reception quality in the measurement processing unit, it is not determined whether or not an event condition is satisfied. Satisfaction of the condition is suppressed in the carrier element.

  (10) A mobile station apparatus according to the present invention is applied to a communication system in which a base station apparatus and a mobile station apparatus perform communication by simultaneously using a plurality of carrier elements defined in mutually different frequency bands. A receiving unit that receives from the base station device an event condition for measuring the reception quality of at least one of the carrier elements and a parameter used to determine whether the event condition is satisfied, and at least one A measurement processing unit that measures reception quality of the two carrier elements, a cell determination unit that determines whether or not to adjust the received parameter, and the event condition is set based on the received parameter or the adjusted parameter And an event determination unit that determines whether or not the set event condition is satisfied.

  Thus, it is determined whether or not to adjust the received parameter, and based on the received parameter or the parameter after adjustment, the event condition is set, and it is determined whether or not the set event condition is satisfied. Since the mobile station apparatus performs event determination by setting event conditions for each carrier element being measured, it can perform efficient event determination. When the mobile station apparatus does not perform event determination, establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event reports is suppressed, so that power consumption in the mobile station apparatus can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus is improved. In addition, since the consumption of radio resources for event reporting is suppressed, the utilization efficiency of radio resources is improved. Moreover, since the base station apparatus can designate the presence / absence of event determination for each cell with respect to the mobile station apparatus, it is possible to perform flexible handover control in accordance with the actual arrangement of the base station apparatus.

  (11) Moreover, in the mobile station apparatus of the present invention, the cell determination unit is configured such that when a plurality of carrier elements that measure reception quality in the measurement unit are used for connection to the base station apparatus, It is determined that the received parameter is adjusted.

  In this way, when a plurality of carrier elements for measuring reception quality are used for connection to the base station apparatus, the received parameters are adjusted, so that establishment of the event condition is suppressed in the carrier elements. become.

  (12) In the mobile station apparatus of the present invention, the cell determination unit includes a reference cell in which a plurality of carrier elements whose reception quality is measured by the measurement processing unit is a reference for measurement of reception quality in the measurement processing unit. If not, it is determined to adjust the received parameter.

  As described above, since the received parameters are adjusted when a plurality of carrier elements for measuring the reception quality are not reference cells serving as a reference for the measurement of the reception quality, establishment of the event condition is suppressed by the carrier elements. It will be.

  (13) Further, in the mobile station apparatus of the present invention, the event determination unit takes a time required until the event condition is satisfied for a carrier element determined by the cell determination unit to adjust the received parameter. The received parameter is adjusted so as to be longer than before the received parameter is adjusted, and it is determined whether or not the set event condition is satisfied.

  As described above, the received parameter is adjusted so that the time required for the event condition to be satisfied is longer than that before adjustment of the received parameter for the carrier element determined to adjust the received parameter. Satisfaction of the condition is suppressed in the carrier element.

  (14) Further, in the mobile station device of the present invention, the event determination unit is configured to detect a carrier element that the cell determination unit determines to adjust the received parameter when the mobile station device is moving at high speed. In this case, the scaling factor used for time adjustment until the event condition is satisfied is invalidated, and it is determined whether or not the set event condition is satisfied.

  In this way, for the carrier element determined to adjust the received parameter, the scaling factor used for time adjustment until the event condition is satisfied is invalidated, and it is determined whether or not the set event condition is satisfied. The establishment of the event condition is suppressed in the carrier element.

  (15) Further, in the mobile station apparatus of the present invention, the event determination unit receives the reception so that establishment of the event condition is suppressed in a carrier element determined by the cell determination unit to adjust the received parameter. The parameters are adjusted.

  In this way, since the received parameters are adjusted so that the establishment of the event condition is suppressed in the carrier element that is determined to adjust the received parameter, unnecessary event conditions are not satisfied, and event information is reported. Since generation | occurrence | production is suppressed, the power consumption in a mobile station apparatus can be reduced.

  (16) Further, the mobile station apparatus of the present invention is applied to a communication system in which a base station apparatus and a mobile station apparatus perform communication using a plurality of carrier elements determined in mutually different frequency bands at the same time. A reception unit that receives an event condition for measuring reception quality of at least one of the carrier elements and a parameter used to determine whether or not the event condition is satisfied, from the base station apparatus; Based on a measurement processing unit that measures the reception quality of at least one carrier element, a cell determination unit that determines whether or not the event condition is satisfied, and a determination result of the cell determination unit And an event determination unit that sets the event condition and determines whether or not the set event condition is satisfied.

  As described above, since it is determined whether or not the event condition is satisfied, the mobile station apparatus performs event determination by setting the event condition for each carrier element being measured. Event determination can be performed. When the mobile station apparatus does not perform event determination, establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event reports is suppressed, so that power consumption in the mobile station apparatus can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus is improved. In addition, since the consumption of radio resources for event reporting is suppressed, the utilization efficiency of radio resources is improved. Moreover, since the base station apparatus can designate the presence / absence of event determination for each cell with respect to the mobile station apparatus, it is possible to perform flexible handover control in accordance with the actual arrangement of the base station apparatus.

  (17) Moreover, in the mobile station apparatus of the present invention, the cell determination unit, when a plurality of carrier elements whose reception quality is measured by the measurement processing unit are used for connection to the base station apparatus, It is determined not to determine whether or not the event condition is satisfied.

  As described above, when a plurality of carrier elements for measuring the reception quality are used for connection to the base station apparatus, it is not determined whether or not the event condition is satisfied. It will be suppressed in the carrier element.

  (18) In the mobile station apparatus of the present invention, the cell determination unit includes a reference cell in which a plurality of carrier elements whose reception quality is measured by the measurement processing unit is a reference for measurement of reception quality in the measurement processing unit. If not, it is determined not to determine whether or not the event condition is satisfied.

  As described above, when a plurality of carrier elements for measuring reception quality are not reference cells serving as a reference for measurement of reception quality in the measurement processing unit, it is not determined whether or not an event condition is satisfied. Satisfaction of the condition is suppressed in the carrier element.

  (19) A base station apparatus according to the present invention is applied to a communication system in which a base station apparatus and a mobile station apparatus perform communication by simultaneously using a plurality of carrier elements defined in mutually different frequency bands. A transmitting unit for notifying the mobile station device of an event condition for the mobile station device to measure the reception quality of at least one carrier element and a parameter used to determine whether or not the event condition is satisfied. It is characterized by providing.

  As described above, the mobile station device notifies the mobile station device of the event condition that is a premise for executing an event that changes the communication state of the mobile station device and the parameter used to determine whether or not the event condition is satisfied. Since event determination is performed by setting event conditions for each carrier element being measured, efficient event determination can be performed. When the mobile station apparatus does not perform event determination, establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event reports is suppressed, so that power consumption in the mobile station apparatus can be reduced. In addition, since the consumption of radio resources for event reporting is suppressed, the utilization efficiency of radio resources is improved. Moreover, since the base station apparatus can designate the presence / absence of event determination for each cell with respect to the mobile station apparatus, it is possible to perform flexible handover control in accordance with the actual arrangement of the base station apparatus.

  (20) In the base station apparatus of the present invention, event determination information for designating whether or not the mobile station apparatus determines whether or not the event condition is satisfied is provided for each mobile station apparatus. An event condition setting unit to be set is further provided, and the transmission unit transmits the event determination information to the mobile station apparatus.

  As described above, since event determination information for specifying whether or not to determine whether or not the event condition is satisfied is set for each mobile station device, the establishment of the event condition is suppressed in the carrier element. become.

  (21) In the base station apparatus of the present invention, the event determination information is set for each event condition, and includes information indicating one or more cell identifiers.

  As described above, since the event determination information is set for each event condition and includes information indicating one or more cell identifiers, the base station device can specify the presence / absence of event determination for each cell with respect to the mobile station device. Therefore, it is possible to perform flexible handover control in accordance with the actual arrangement of base station apparatuses.

  According to the embodiment of the present invention, since the mobile station apparatus sets an event condition for each carrier element and performs event determination, it can perform efficient event determination. Moreover, since the mobile station apparatus does not transmit unnecessary measurement reports to the base station apparatus, it is possible to reduce power consumption. In addition, the mobile station apparatus improves the communication quality because the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced. Moreover, since the consumption of radio resources for reporting event information is suppressed, the utilization efficiency of radio resources is improved. Since the base station apparatus controls the handover based on the measurement report from the mobile station apparatus, complicated control is not required and scheduling complexity is reduced.

It is a block diagram which shows schematic structure of the base station apparatus 3 which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of the mobile station apparatus 1 which concerns on embodiment of this invention. It is a sequence chart regarding the measurement process of the mobile station apparatus 1 which concerns on embodiment of this invention. It is a flowchart which shows the parameter adjustment process of the mobile station apparatus 1 which concerns on the 1st Embodiment of this invention. It is a figure which shows the presence or absence of parameter adjustment when the mobile station apparatus 1 which concerns on the 1st Embodiment of this invention compares the reception quality of a carrier element (cell). It is a flowchart which shows the parameter adjustment process of the mobile station apparatus 1 which concerns on the 2nd Embodiment of this invention. It is a figure which shows the presence or absence of the parameter adjustment at the time of the mobile station apparatus 1 which concerns on the 2nd Embodiment of this invention comparing reception quality for every carrier element (cell). It is a flowchart which shows the parameter adjustment process of the mobile station apparatus 1 which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows a parameter adjustment process in case the reference cell is designated in the mobile station apparatus 1 which concerns on the 3rd Embodiment of this invention. When the base station apparatus 3 according to the third embodiment of the present invention notifies the mobile station apparatus 1 of the event condition, the base station apparatus 3 is referred to specify a cell for performing parameter adjustment processing for each event condition. It is an example of a table. It is a figure which shows an example of the increase / decrease in the receiving frequency band using a carrier aggregation. It is a figure explaining the measurement object cell and the measuring method. It is a figure which shows an example of the communication network structure which concerns on embodiment of this invention. It is the figure which showed the example of the correspondence of the downlink component carrier comprised when the mobile station apparatus 1 which concerns on embodiment of this invention performs a carrier aggregation, and an uplink component carrier.

  Before describing the embodiments of the present invention, carrier aggregation, handover parameters, and physical channels related to the present invention will be briefly described.

(1) Carrier Aggregation FIG. 11 is a diagram illustrating an example of increase / decrease in the reception frequency band using carrier aggregation. Band 1 to Band 3 indicate downlink frequency bands (component carriers) transmitted from the base station apparatus, and a plurality of frequency bands can be simultaneously used for connection with one mobile station apparatus by carrier aggregation. Band 1 to Band 3 are different frequencies. Note that the transmission bandwidths of the frequency bands of Band1 to Band3 may be the same, or some or all of them may be different. Band1 to Band3 may be continuous frequency bands or discontinuous frequency bands. Each frequency band may be a frequency band that can be used only by an advanced EUTRA mobile station apparatus, or may be a frequency band that can be used by both an advanced EUTRA mobile station apparatus and an EUTRA mobile station apparatus. The mobile station apparatus of this example can receive up to three 20 MHz frequency bands simultaneously, and the total reception bandwidth is 60 MHz.

  In the example of FIG. 11, at a certain time Time1, the mobile station apparatus communicates with the base station apparatus using 20 MHz of Band3, and simultaneously measures Band1 to Band2. At another time Time2, Band 2 is added to the mobile station apparatus, and communication is performed with the base station apparatus using a total of 40 MHz of Band 2 and Band 3, and Band 1 is measured at the same time. Further, at another time Time3, Band1 is further added to the mobile station apparatus, and communication is performed with the base station apparatus using a total of 60 MHz of Band1 to Band3. Also, at some other time Time4, the mobile station apparatus is deleting Band2 and is communicating with the base station apparatus using a total of 40 MHz of Band1 and Band3, and simultaneously measuring Band2. Thus, by using carrier aggregation, it is possible to significantly improve the data rate without greatly changing the configuration of the base station apparatus. Note that the time lengths of Time 1 to Time 4 are variable, and the time lengths do not have to be the same.

When using a communication method such as OFDMA (Orthogonal Frequency Division Multiplexing Access) in which a guard interval (CP) is provided for each symbol, the OFDM symbol timing of each frequency band used for carrier aggregation must be equal. Is desirable. The equal OFDM symbol timing means that the difference in the reception timing of OFDM symbols in each frequency band falls within the CP length at the receiving antenna end of the mobile station apparatus. It is also possible to apply the carrier aggregation described above to the uplink frequency band transmitted by the mobile station apparatus. When carrier aggregation is applied to the uplink frequency band, it is desirable that the transmission timing of the uplink frequency band is the same or the difference is within the CP length.

(2) Handover parameters Handover parameters are a plurality of quasi-static parameter groups held internally by the base station apparatus in order to cause the mobile station apparatus to determine the timing of handover. Here, handover in EUTRA and handover parameters will be described. In the handover, the event conditions applied to the reception quality (Ms) of the currently connected cell (cell in which the cell is located) and the reception quality (Mn) of other cells (neighboring cells) are changed from the base station device to the mobile station device. When the event condition is met and the event condition is met, the event condition is met and reported to the base station apparatus. The reception quality is obtained by the mobile station apparatus measuring the reference signal received power (RSRP) or the reference signal received quality (RSRQ) of the downlink reference signal.

Event conditions related to handover (also referred to as handover conditions) are typically set for each cell and the offset value (Oc) set for each cell and the reception quality of the serving cell and neighboring cells. Offset value (Of) is added, and the result of adding the event offset value (Off) to the reception quality of the serving cell is compared, and the reception quality of the neighboring cells exceeds the reception quality of the serving cell. It is established by that. In addition, the base station apparatus sets a hysteresis (Hysteresis) that adjusts the reception quality of neighboring cells so that handovers do not occur frequently, and a required time (TTT; Time To Trigger) until the handover condition is satisfied. Notify the mobile station device. That is, the handover parameters include an offset value for each cell, an offset value for each frequency band, an event offset value, hysteresis, and TTT.

FIG. 12 is a diagram illustrating the measurement target cell and the measurement method. The correspondence for each cell regarding event determination will be described with reference to FIG. A cell A1 and a cell A2 in FIG. 12 are cells that are spatially arranged in the same area and are operated at different frequencies F1 and F2. Similarly, the cell B1 and the cell B2 are spatially arranged in the same area and are operated at different frequencies F1 to F2. At this time, when the serving cell is the cell A2, the handover from the cell A2 to the cell A1 or the cell B1 is a different frequency handover, and the cell A2 includes the offset value (Oc_A2) of the cell A2 and the frequency F2. An offset value (Of_F2) and an event offset value (Off) are added. In addition, an offset value (Oc_A1) of the cell A1, an offset value (Of_F1) of the frequency F1, and hysteresis are added to the cell A1. Further, the offset value (Oc_B1) of the cell B1, the offset value (Of_F1) of the frequency F1, and hysteresis are added to the cell B1. The handover from the cell A2 to the cell B2 is the same frequency handover, and the offset value (Oc_A2) of the cell A2 and the event offset value (Off) are added to the cell A2. In addition, the offset value (Oc_B2) and hysteresis of the cell B2 are added to the cell B2. The hysteresis and TTT used for the handover condition are set for each frequency band. Negative values may be set for the offset value and hysteresis.

  Further, the base station apparatus designates a scaling factor (Scaling Factor) for shortening (or extending) the TTT in order to reduce the time required until the handover condition is satisfied depending on the moving speed of the mobile station apparatus. It is also possible. That is, the scaling factor is used to shorten (or extend) the time required until the handover condition is satisfied. The base station device can specify the scaling coefficient for each moving speed of the mobile station device. For example, the base station device moves at a high speed and a medium speed moving slower than the high speed moving with respect to the mobile station device. You can specify a different scaling factor with. The base station apparatus can also assign a different scaling factor for each mobile station apparatus. When the mobile station apparatus determines that the mobile station apparatus is moving at high speed when 0.5 is designated as the scaling factor during high-speed movement from the base station apparatus, the mobile station apparatus sets 0 to the notified TTT. A value obtained by multiplying .5 is set as TTT, and event determination is performed. Thus, the scaling coefficient and the moving speed (moving speed information) are also included in the handover parameter because they are related to the handover condition. The moving speed information is generated by the mobile station apparatus according to the number of handovers that have occurred within a predetermined time.

(3) 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.

  The synchronization signal is used by the mobile station apparatus to detect the base station apparatus (or relay station apparatus) at high speed. The synchronization signal is composed of three types of primary synchronization signals and secondary synchronization signals composed of 31 types of codes arranged alternately in the frequency domain, and the base station is configured by combining the primary synchronization signal and the secondary synchronization signal. 504 kinds of cell identifiers (cell IDs) for identifying a device and frame timing for radio synchronization are shown. The mobile station apparatus specifies the cell ID 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) that are commonly used by mobile station apparatuses in a cell. The broadcast information that is not notified on the physical broadcast information channel is transmitted using the downlink data channel with the radio resource notified on the downlink shared control channel. As broadcast information, access restriction information, a cell global ID 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 shared control channel or the 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. The downlink reference signal may be described as a cell-specific reference signal (RS), but its use and meaning are the same.

The downlink shared control channel (PDCCH; Physical Downlink Common Channel) is transmitted in some OFDM symbols from the beginning of each subframe, radio resource allocation information according to the scheduling of the base station device to the mobile station device, It is used for the purpose of instructing the adjustment amount of increase / decrease of transmission power. The mobile station device receives the downlink shared control channel before transmitting / receiving downlink data (downlink traffic data) and control messages, acquires uplink grant during transmission, and acquires radio resource allocation information from the downlink grant during reception There is a need to.

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

  An uplink data channel (PUSCH: Physical Uplink Shared Channel) mainly transmits uplink data (uplink traffic 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 shared control channel.

A random access channel (PRACH) is a channel used for notifying a preamble sequence and has a guard time. The random access channel is used as an access procedure to the base station apparatus of a mobile station apparatus whose uplink transmission timing is asynchronous, 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.

[Example of communication network configuration of the present invention]
FIG. 13 is a diagram illustrating an example of a communication network configuration according to the embodiment of the present invention. When the mobile station apparatus 1 can be connected to the base station apparatus 3 by simultaneously using a plurality of frequency bands (component carriers, Band1 to Band3) by carrier aggregation, the communication network configuration is one base station. The apparatus 3 includes transmission apparatuses 11 to 13 (reception apparatuses 21 to 23 (not shown)) for each of a plurality of frequency bands, and the configuration in which the control of each frequency band is performed by one base station apparatus 3 is a viewpoint of simplifying the control. To preferred. However, the base station apparatus 3 may be configured to transmit a plurality of frequency bands with a single transmission apparatus because the plurality of frequency bands are continuous frequency bands. The communicable range of each frequency band controlled by the transmission device of the base station device 3 is regarded as a cell and exists in the same spatial area. At this time, the areas (cells) covered by each frequency band may have different widths, that is, different radii. However, in the description to be described later, each area of the frequency of the carrier element formed by the base station apparatus 3 will be referred to as a cell, but this may be different from the definition of the cell in the actually operated communication system. Note that there is. For example, in some communication systems, component carriers used by carrier aggregation may be defined as simply additional radio resources rather than cells. By referring to the component carrier as a cell in the present invention, even if a case different from the definition of the cell in the actually operated communication system occurs, the gist of the present invention is not affected.

[Example of correspondence between component carriers]
FIG. 14 is a diagram illustrating an example of a correspondence relationship between a configured downlink component carrier and an uplink component carrier when the mobile station apparatus 1 according to the embodiment of the present invention performs carrier aggregation. The downlink component carrier DL_CC1 corresponds to the uplink component carrier UL_CC1. That is, ACK / NACK of data received by DL_CC1 and feedback of reception quality are transmitted by UL_CC1. In addition, a case where a plurality of downlink component carriers correspond to the uplink component carrier is also possible. In the example of the figure, both ACK / NACK of data received by DL_CC2 and DL_CC3 and feedback of reception quality are transmitted by UL_CC2.

  The mobile station apparatus 1 performs a normal cell search procedure without particularly being aware of which base station apparatus 3 the downlink component carrier is transmitted from and which base station apparatus 3 receives the uplink component carrier. Use to select. Then, the mobile station apparatus 1 acquires information such as the frequency band and bandwidth of the uplink component carrier corresponding to the downlink component carrier from the broadcast information of the selected cell. The base station apparatus 3 may individually set the correspondence relationship between the downlink component carrier and the uplink component carrier for each mobile station apparatus 1. The mobile station device 1 starts carrier aggregation based on an instruction from the base station device 3, and starts transmission / reception with respect to a plurality of component carriers.

  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, when it is determined that a specific description of a known function or configuration related to the present invention obscures the gist of the present invention, a detailed description thereof is omitted.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
A first embodiment of the present invention will be described below. In the present embodiment, when the mobile station apparatus 1 uses a plurality of downlink frequency bands (downlink component carriers) by carrier aggregation, an event condition for the mobile station apparatus 1 to efficiently perform event determination The present invention relates to a parameter adjustment method.

  FIG. 1 is a block diagram showing a schematic configuration of a base station apparatus 3 according to the 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, and a control unit 119. The

  The upper layer 107 inputs downlink data and downlink control data to the encoding unit 109. The encoding unit 109 encodes the 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.

The upper layer 107 sets an event condition for each mobile station device 1. The event conditions and handover parameters output from the upper layer 107 are input as downlink data to the encoding unit 109 and the modulation unit 111 when the event conditions need to be set, and are transmitted to the physical broadcast information channel or the downlink data channel. Are appropriately arranged and transmitted as a transmission signal. The downlink data channel in which the handover parameter transmitted by the base station apparatus 3 is arranged typically forms a layer 3 message (RRC message).

The receiving unit 101 converts the signal received from the mobile station apparatus 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 related to scheduling necessary for 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 by the encoding unit 109, the modulation unit 111, and the RS. 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 the generation unit 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.

  The handover parameters are preferably managed for each base station apparatus 3, but a control station apparatus higher than the base station apparatus 3 manages the handover parameters and performs handover from the higher control station apparatus as appropriate. The management method may be such that the parameter is notified to the base station apparatus 3, or the handover parameter is notified to the base station apparatus 3 in response to a request from the base station apparatus 3.

  FIG. 2 is a block diagram showing a schematic configuration 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, an event determination 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, upper layer 223, and cell determination part 225. 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 mobile station device 1 may include a plurality of reception units 201 and transmission units 217.

  The reception signal is received by the reception unit 201. The receiving unit 201 receives a signal in the frequency band specified 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. When the handover parameter is decoded, the handover parameter is input to the event determination unit 209. In addition, the handover parameter may be input from the upper layer 223 to the event determination unit 209. The measurement processing unit 207 performs a measurement process based on the measurement process of the reception quality of the downlink reference signal for each cell and the measurement result of the reception error rate of the downlink shared control channel or the downlink data channel. Is measured (sampled) for each sample, and the measurement information is output to the upper layer 223 and, if necessary, the event determination unit 209.

In the event determination unit 209, in addition to the event condition, handover parameter, and measurement information, if the mobile station device 1 is connected using carrier aggregation, the component carrier connected by carrier aggregation is uniquely identified. The carrier element information, which is information for doing this, is input. The carrier element information may be in any format as long as it is information that can identify the component carrier being connected using the carrier aggregation currently used by the mobile station apparatus 1 for connection. For example, it may be configured by an absolute radio frequency channel number (ARFCN) and a cell ID.

  The event determination unit 209 inputs the input carrier element information to the cell determination unit 225. The cell determination unit 225 performs a cell determination process for determining a relationship for each cell (carrier element) of the frequency to be measured from the input carrier element information, and the cell determination result information that is the determination result is determined by the event determination unit 209. Output for. The cell determination result information indicates information on whether or not to adjust the handover parameter for each cell. Further, the event determination unit 209 performs an event determination process for evaluating whether or not the event condition (handover condition) is satisfied based on the input event condition, handover parameter, measurement information, and cell determination result information. Do. Then, when the event condition is satisfied, the event determination unit 209 outputs event information indicating the established event condition to the upper layer 223. The event information includes at least an event identifier (Event ID) indicating the type of event condition that is satisfied and a cell ID of a cell (carrier element) that satisfies the event condition. When a carrier element ID that is an ID assigned to each carrier element is used to identify the connected carrier element, the event determination unit 209 can also include the carrier element ID instead of the cell ID. . The carrier element ID is assigned every time the base station apparatus 3 is connected by carrier aggregation and a carrier element is designated. The event determination unit 209 and the cell determination unit 225 may be sub-functional blocks of the upper layer 223. The event condition is notified by 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 217. The transmitter 217 maps the output of the modulator 215 to the frequency domain, converts the frequency domain signal into a time domain signal, performs power amplification on a predetermined frequency carrier wave, 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 event information transmitted by the mobile station apparatus 1 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.

  Further, the correspondence relationship between the communication network configuration and the frequency band of the communication system in which the base station apparatus 3 and the mobile station apparatus 1 are arranged can be the same as those shown in FIGS. 13 and 14, respectively.

  FIG. 3 is a sequence chart diagram relating to the measurement processing of the mobile station apparatus 1 according to the embodiment of the present invention. An event determination processing method according to the present invention will be described with reference to the sequence chart of FIG. FIG. 3 shows that the mobile station device 1 and the frequency of the carrier element 1 to the frequency of the carrier element 4 (component carrier 1 to component carrier 4) exist, and the mobile station device 1 performs the carrier aggregation to the frequency of the carrier element 1 It starts from a state (carrier aggregation state) in which the base station device 3 is connected using the frequency band of the frequency of the carrier element 3. The frequency of the carrier element 1 to the frequency of the carrier element 3 are different frequency bands. The mobile station apparatus 1 receives the frequency of the carrier element 1 to the frequency of the carrier element 3 to be carrier-aggregated at the same spatial location. However, the cell radius of the frequency of each carrier element may be different. The frequency of the carrier element 4 is not connected to the mobile station device 1. The frequency of the carrier element 4 may be the same frequency as the frequency of the carrier element 1 to the frequency of the carrier element 3 or may be a different frequency. The frequency of the carrier element 4 may be a frequency used by another base station device 3 not connected to the mobile station device 1.

  Unless otherwise specified, the frequency of the carrier element means a set of downlink component carriers and uplink component carriers corresponding to the downlink component carriers. In addition, transmission from the mobile station apparatus 1 to the carrier element frequency in the figure means transmission to the base station apparatus 3 using an uplink component carrier, and transmission from the carrier element frequency to the mobile station apparatus 1 is This means transmission from the base station apparatus 3 to the mobile station apparatus 1 using a downlink component carrier. Hereinafter, the frequency of the carrier element is sometimes simply referred to as a carrier element or a cell. A cell having a frequency of a carrier element that is measured by the mobile station apparatus 1 for event determination is particularly referred to as a measurement target cell. Actually, downlink or uplink radio resource allocation information by the downlink shared control channel is required prior to transmission / reception of each control message, which is omitted in the drawings and description.

The base station apparatus 3 transmits measurement control information to the mobile station apparatus 1 using the frequency of any carrier element (step S101). The measurement control information includes event conditions and handover parameters (reception quality for each measurement target cell and each parameter (offset value, frequency for each cell, frequency used for comparison between the reception quality of the measurement target cell and a threshold). Offset value per band, hysteresis, TTT), and scaling factor). Measurement control information is set for each frequency band. Further, the measurement control information may be transmitted as broadcast information as common information in the cell, or may be transmitted as individual information of the connected mobile station apparatus 1. Further, only the measurement control information may be transmitted as a layer 3 message, may be transmitted together with a layer 3 message related to the radio connection setting or radio connection setting change of the mobile station apparatus 1, or may be transmitted together with downlink data. May be sent to. Moreover, it may be distributed and transmitted in a plurality of layer 3 messages. The wireless connection setting is, for example, RRC Connection Setup, and the wireless connection setting change is, for example, RRC Connection Reconfiguration.

  The mobile station apparatus 1 holds the measurement control information transmitted from the base station apparatus 3 inside the mobile station apparatus 1 until new measurement control information is received or until the connection with the base station apparatus 3 is terminated. to continue. After holding the measurement control information, the mobile station apparatus 1 obtains the mobile station apparatus speed information by determining the moving speed of the local station (step S103). The moving speed information is determined by comparing the number of cells moved by handover within a predetermined time with a threshold value. The predetermined time and threshold used for the determination are notified from the base station apparatus 3 to the mobile station apparatus 1. For example, if the number of cells is less than the threshold 1, the mobile station device 1 determines that the speed is S1, if the threshold is 1 or more and less than the threshold 2, determines that the speed is S2, and if the number is 2 or more, the speed is S3. judge. By increasing the threshold value, the mobile station apparatus 1 can also determine a finer moving speed. The mobile station apparatus 1 holds the movement speed information determined by the determination of the movement speed in the mobile station apparatus 1 as a handover parameter.

Subsequently, the mobile station apparatus 1 receives the downlink reference signal in each carrier element (step S105), and measures the reception quality for each carrier element. Then, in order to calculate the reception quality for each carrier element that is the measurement target, the offset value for each cell and the offset value for each frequency band, the offset value for each event, the offset value for the event, and the hysteresis for the measured reception quality Add Then, the mobile station apparatus 1 compares the reception quality for each carrier element (cell) using the calculated reception quality, and determines whether the event condition is satisfied in the time required for the event condition to be satisfied (TTT). Based on the determination (step S107).

  The mobile station apparatus 1 according to the present embodiment determines the relationship for each carrier element from the carrier element information in event determination, and performs event determination after performing parameter adjustment processing for correcting parameters used in event conditions according to the determination result. . When the event condition is satisfied, the mobile station apparatus 1 includes the event information thus satisfied in a measurement report that is a layer 3 message, and transmits it to the base station apparatus 3 using any of the connected carrier elements ( Step S109). In the figure, the mobile station apparatus 1 transmits a measurement report with respect to the frequency of the carrier element 1, but may be transmitted with the frequency of another connected carrier element 2 or the frequency of the carrier element 3. The measurement report is, for example, a measurement report of a layer 3 message.

  FIG. 4 is a flowchart showing parameter adjustment processing of the mobile station apparatus 1 according to the first embodiment of the present invention. The parameter adjustment process is executed as a part of the process when the reception quality is compared for each carrier element (cell) in the event determination process of FIG. The mobile station apparatus 1 performs a cell determination process for determining whether or not the measurement target cell is connected using carrier aggregation from the carrier element information (step S201). For example, if the mobile station apparatus 1 compares the reception quality between the frequency of the carrier element 1 and the frequency of the carrier element 2 in FIG. 3, the mobile station apparatus 1 determines that the measurement target cell is connected using carrier aggregation, Parameter adjustment is performed and the adjusted value is used (step S203). On the other hand, if the mobile station apparatus 1 compares the reception quality between the frequency of the carrier element 1 and the frequency of the carrier element 4 in FIG. 3, the mobile station apparatus 1 determines that the measurement target cell is not connected using carrier aggregation, The parameter value is not adjusted and the notified value is used as it is (step S205).

Here, the parameter adjustment is performed by correcting any one of the handover parameters so as to have a value different from the value notified from the base station apparatus 3. For example, increasing the event offset value (Off). Alternatively, the hysteresis (Hysteresis) for adjusting the reception quality of neighboring cells is reduced. Alternatively, the time (TTT) indicating the time required until the event condition is satisfied is lengthened.

  As another control content of parameter adjustment, there is a method of correcting the notified event condition by adding a new handover parameter to the event condition. For example, an offset value (COff) for the connected carrier element is added to the measured reception quality of the carrier element using carrier aggregation. Further, the event condition may not be satisfied when the parameters are adjusted by setting each of the above handover parameters (TTT, Off, Hysteresis, COff) to infinity. As long as the parameter adjustment method is such that the establishment of the event condition is suppressed more than usual, any parameter adjustment method may be used, not limited to the correction method described above.

  FIG. 5 is a diagram showing presence / absence of parameter adjustment when the mobile station apparatus 1 according to the first embodiment of the present invention compares the reception quality of carrier elements (cells). Cells A1 to A3 are cells that are spatially arranged in the same area and are operated at different frequencies F1 to F3. Similarly, the cell B1 and the cell B2 are spatially arranged in the same area and are operated at different frequencies F1 to F2. At this time, when the cell A1 and the cell A2 are connected to a certain mobile station device 1 using carrier aggregation, the mobile station device 1 compares the reception quality between the cell A1 and the cell A2. When performing, the mobile station apparatus 1 performs parameter adjustment. When the mobile station apparatus 1 compares the reception quality in other cells, the mobile station apparatus 1 does not perform parameter adjustment (for example, comparison between the cell A1 and the cell B1).

  As described above, in the first embodiment, the parameter adjustment used for the event condition is performed when the reception quality is compared for each connected carrier element by using carrier aggregation. That is, when the two carrier elements to be compared are connected using carrier aggregation, the mobile station apparatus 1 performs parameter adjustment, whereby the establishment of the event condition is suppressed in the carrier element.

  As described above, the mobile station apparatus 1 appropriately adjusts the parameters based on the handover parameter notified from the base station apparatus 3 and the carrier element information indicating whether the connection is established using the carrier aggregation. . Therefore, since the mobile station apparatus 1 performs event determination by appropriately setting event conditions for each carrier element being measured, it is possible to perform efficient event determination. When the mobile station apparatus 1 performs parameter adjustment, establishment of the event condition is suppressed more than usual. As described above, unnecessary event conditions are not satisfied, and the occurrence of reporting of event information is suppressed, so that power consumption in the mobile station apparatus 1 can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus 1 is improved. Moreover, since the consumption of radio resources for reporting event information is suppressed, the utilization efficiency of radio resources is improved. Since the base station apparatus 3 controls the handover based on the measurement report from the mobile station apparatus 1, complicated control is not required, and scheduling complexity is reduced.

<Second Embodiment>
A second embodiment of the present invention will be described below. In the present embodiment, an event condition for the mobile station apparatus 1 to efficiently perform event determination when the mobile station apparatus 1 is set with a reference cell when comparing the reception quality of each carrier element. The present invention relates to a parameter adjustment method.

  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 difference is that the reference cell information is included in the carrier element information input to the event determination unit of the mobile station apparatus 1. Further, the correspondence relationship between the communication network configuration and the frequency band of the communication system in which the base station apparatus 3 and the mobile station apparatus 1 are arranged can be the same as those shown in FIGS. 13 and 14, respectively. The sequence chart relating to event determination may be the same as in FIG.

  A carrier element (reference cell) serving as a reference when the mobile station apparatus 1 compares the reception quality for each carrier element is an anchor component carrier (a set of an anchor uplink component carrier and an anchor downlink component carrier) or an anchor cell. Sometimes called. The reference cell may be common for each cell, or may be individually specified for each mobile station apparatus 1. The reference cell may be explicitly designated from the base station apparatus 3 to the mobile station apparatus 1 or may be implicitly designated. The mobile station apparatus 1 may select by an arbitrary method and report the selection result to the base station apparatus 3. The mobile station apparatus 1 may receive the downlink shared control channel only for the carrier element that is the reference cell, or may measure the downlink reception quality only for the carrier element that is the reference cell. The base station apparatus 3 may set the event condition only for comparison with a carrier element that is a reference cell. In this way, by setting a reference cell for the mobile station apparatus 1, a measurement method centering on the carrier element that is the reference cell is possible, so that the control necessary for the measurement processing of the mobile station apparatus 1 is simplified. It becomes.

  FIG. 6 is a flowchart showing parameter adjustment processing of the mobile station apparatus 1 according to the second embodiment of the present invention. The mobile station apparatus 1 performs a cell determination process for determining whether or not the measurement target cell is connected using carrier aggregation from the carrier element information (step S301). Further, the mobile station device 1 grasps which carrier element the reference cell is. If the measurement target cell is being connected using carrier aggregation, the mobile station device 1 performs parameter adjustment and uses the adjusted value (step S303). On the other hand, when the measurement target cell is not connected using carrier aggregation, the mobile station apparatus 1 determines whether the measurement target cell is a comparison with the reference cell (step S305). If the measurement target cell is a comparison with the reference cell, the notified value is used as it is without adjusting the parameters (step S307).

  That is, in the carrier element information in the second embodiment, information indicating whether or not the carrier element for which the mobile station apparatus 1 compares the reception quality is connected using carrier aggregation can be identified from the reference cell. Information must be included at least. Since the method described in the first embodiment can be used as the parameter adjustment method, description thereof is omitted.

  FIG. 7 is a diagram showing presence / absence of parameter adjustment when the mobile station apparatus 1 according to the second embodiment of the present invention compares reception quality for each carrier element (cell). Since the elements in FIG. 7 are the same as those in FIG. However, the cell A2 is a reference cell. At this time, when the cell A1 and the cell A2 are connected to a certain mobile station device 1 using carrier aggregation, the mobile station device 1 compares the reception quality between the cell A1 and the cell A2. When performing, the mobile station apparatus 1 performs parameter adjustment. When the mobile station apparatus 1 compares the reception quality of other cells, the mobile station apparatus 1 does not adjust parameters if the reception quality is compared with the reference cell (for example, comparison between the cell A2 and the cell B1). . When the mobile station apparatus 1 compares the reception quality with other than the reference cell, the mobile station apparatus 1 performs parameter adjustment (for example, comparison between the cell A1 and the cell B2).

  As described above, in the second embodiment, the parameter adjustment used for the event condition is not only when the reception quality is compared for each connected carrier element using carrier aggregation, but also when the mobile station apparatus 1 is other than the reference cell. This is performed when the reception quality of the carrier elements is compared. That is, when the two carrier elements to be compared by the mobile station apparatus 1 are connected using carrier aggregation, or when neither of them is a reference cell, the mobile station apparatus 1 performs parameter adjustment to establish the event condition. It will be suppressed in the carrier element.

  As described above, the mobile station device 1 determines whether the handover parameter notified from the base station device 3 and the carrier element for which the mobile station device 1 compares the reception quality are connected using carrier aggregation. The parameter is appropriately adjusted based on carrier element information indicating whether the cell is a reference cell. Therefore, since the mobile station apparatus 1 performs event determination by appropriately setting event conditions for each carrier element being measured, it is possible to perform efficient event determination. When the mobile station apparatus 1 performs parameter adjustment, establishment of the event condition is suppressed more than usual. As described above, unnecessary event conditions are not satisfied, and the occurrence of reporting of event information is suppressed, so that power consumption in the mobile station apparatus 1 can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus 1 is improved. Moreover, since the consumption of radio resources for reporting event information is suppressed, the utilization efficiency of radio resources is improved. Since the base station apparatus 3 controls handover based on the measurement report from the mobile station apparatus 1, complicated control is not required, and scheduling complexity is reduced. In addition, the measurement method can be simplified by using the reference cell, and the control complexity of the mobile station device 1 or the base station device 3 can be reduced.

<Third Embodiment>
A third embodiment of the present invention will be described below. The present embodiment shows an event determination method for determining the presence / absence of event determination for each carrier element when the mobile station apparatus 1 compares the reception quality of each carrier element.

  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. The reference cell information may or may not be included in the carrier element information input to the event determination unit of the mobile station device 1. Further, the correspondence relationship between the communication network configuration and the frequency band of the communication system in which the base station apparatus 3 and the mobile station apparatus 1 are arranged can be the same as those shown in FIGS. 13 and 14, respectively. The sequence chart relating to event determination may be the same as in FIG.

  FIG. 8 is a flowchart showing parameter adjustment processing of the mobile station apparatus 1 according to the third embodiment of the present invention. The mobile station apparatus 1 performs a cell determination process for determining whether or not the measurement target cell is connected using carrier aggregation from the carrier element information (step S401). If the measurement target cell is connected using carrier aggregation, the mobile station apparatus 1 determines that the measurement target cell is a non-event determination cell that does not require event determination, and the reception quality of the measurement target cell is determined. Is not used for event determination (step S403). On the other hand, if the measurement target cell is not connected using carrier aggregation, the parameter value is not adjusted and the notified value is used as it is (step S405).

  FIG. 9 is a flowchart showing parameter adjustment processing when a reference cell is designated in the mobile station apparatus 1 according to the third embodiment of the present invention. Another method of parameter adjustment processing in the mobile station device 1 of the third embodiment will be described using the flowchart of FIG. The mobile station apparatus 1 performs a cell determination process for determining whether or not the measurement target cell is connected using carrier aggregation from the carrier element information (step S501). In addition, it grasps which carrier element the reference cell is. If the measurement target cell is connected using carrier aggregation, the mobile station device 1 determines that the target cell is a non-event determination cell, and the reception quality of the measurement target cell is determined for event determination. Not used (step S503). On the other hand, when the measurement target cell is not connected using carrier aggregation, the mobile station device 1 determines whether the measurement target cell is a comparison with the reference cell (step S505). If the measurement target cell is compared with the reference cell, the mobile station device 1 uses the notified value as it is without adjusting the parameters (step S507).

  In the parameter adjustment process, as a control of the mobile station apparatus 1 when the mobile station apparatus 1 determines that the measurement target cell is a non-event determination cell, the mobile station apparatus 1 moves when the event condition notified from the base station apparatus 3 is satisfied. Other methods may be used as long as the station device 1 does not report the establishment of the event condition to the base station device 3. For example, the mobile station apparatus 1 may perform the event determination as usual, but may use a method such as not reporting to the base station apparatus 3 that the event condition is satisfied in the event non-determined cell.

  The base station device 3 can also explicitly specify the presence / absence of this parameter adjustment processing for each cell. For example, the base station apparatus 3 can also specify that a certain cell applies this parameter adjustment processing method only to a specific event condition and does not apply it to other event conditions.

  FIG. 10 is a diagram for specifying a cell for performing parameter adjustment processing for each event condition when the base station apparatus 3 according to the third embodiment of the present invention notifies the mobile station apparatus 1 of the event condition. It is an example of the table referred to by. In addition, the base station apparatus 3 may notify the table shown in FIG. 10 to the mobile station apparatus 1 in the cell using broadcast information, or may notify each mobile station apparatus 1 individually, You may notify for every event condition notified when notifying event conditions for every mobile station apparatus 1. FIG. In the latter preferred notification method, the cell ID indicating a non-event determination cell or a plurality of cell IDs are indicated in the measurement control information used when the base station apparatus 3 notifies the mobile station apparatus 1 of the event condition. A cell ID group (which may be a range designation indicating the start and end of successive cell IDs) is designated for each event condition to be set, and the table shown in FIG. That is, the base station apparatus 3 sets event determination information that specifies whether or not the mobile station apparatus 1 performs event determination for one or more specified cell IDs, and uses the event determination information as measurement control information. At the same time, it is transmitted to the mobile station apparatus 1.

  As described above, in the third embodiment, event determination is not performed when the mobile station apparatus 1 compares the reception quality for each connected carrier element using carrier aggregation. That is, when two carrier elements to be compared by the mobile station apparatus 1 are connected using carrier aggregation, the mobile station apparatus 1 does not perform event determination, so that establishment of the event condition is suppressed in the carrier element. It will be.

  As described above, the mobile station apparatus 1 determines the presence / absence of the event determination based on the carrier element information indicating whether the carrier element with which the mobile station apparatus 1 compares the reception quality is connected using carrier aggregation. To do. Therefore, since the mobile station apparatus 1 performs event determination by setting event conditions for each carrier element being measured, it is possible to perform efficient event determination. When the mobile station device 1 does not perform event determination, the establishment of the event condition is suppressed more than usual. In this way, unnecessary event conditions are not satisfied, and the occurrence of event reports is suppressed, so that power consumption in the mobile station apparatus 1 can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus 1 is improved. In addition, since the consumption of radio resources for event reporting is suppressed, the utilization efficiency of radio resources is improved. In addition, since the base station apparatus 3 can explicitly specify the presence / absence of event determination for each cell with respect to the mobile station apparatus 1, it performs flexible handover control in accordance with the actual arrangement of the base station apparatus 3. be able to.

<Fourth Embodiment>
A fourth embodiment of the present invention will be described below. The present embodiment shows an event determination method when the mobile station apparatus 1 moving at high speed compares the reception quality of each carrier element. 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. The reference cell information may or may not be included in the carrier element information input to the event determination unit of the mobile station device 1. Further, the correspondence relationship between the communication network configuration and the frequency band of the communication system in which the base station apparatus 3 and the mobile station apparatus 1 are arranged can be the same as those shown in FIGS. 13 and 14, respectively. The sequence chart relating to event determination may be the same as in FIG.

The mobile station device 1 takes the time required for the event condition to be satisfied in the event determination (TTT
) Is adjusted based on the moving speed information, the scaling factor, and the carrier element information. The mobile station apparatus 1 does not reduce (or extend) the TTT value based on the scaling factor for the carrier element determined as “with parameter adjustment” in the first embodiment or the second embodiment. In the present embodiment, only this embodiment can be applied as a parameter adjustment method, or can be applied in combination with the first embodiment or the second embodiment. When applied in combination with the first embodiment or the second embodiment, it is desirable that the parameter adjustment processing in the first embodiment or the second embodiment is performed on parameters other than TTT.

  As described above, in the fourth embodiment, the mobile station device 1 moving at high speed does not apply the scaling coefficient that is applied when the reception quality of the connected carrier element is compared using carrier aggregation. That is, when two carrier elements to be compared by the mobile station apparatus 1 are connected using carrier aggregation, the establishment of the event condition is suppressed in the carrier element by the mobile station apparatus 1 not applying the scaling factor. It will be.

  As described above, in the mobile station device 1 that is moving at high speed, the handover parameter notified from the base station device 3 and the carrier element for which the mobile station device 1 compares the reception quality are being connected using carrier aggregation. The parameter is appropriately adjusted based on the carrier element information indicating whether or not. Therefore, since the mobile station apparatus 1 performs event determination by setting event conditions for each carrier element being measured, it is possible to perform efficient event determination. When the mobile station apparatus 1 performs parameter adjustment, establishment of the event condition is suppressed more than usual. As described above, unnecessary event conditions are not satisfied, and the occurrence of reporting of event information is suppressed, so that power consumption in the mobile station apparatus 1 can be reduced. In addition, since the communication disconnection probability and the handover failure probability associated with unnecessary handover processing are reduced, the communication quality in the mobile station apparatus 1 is improved. Moreover, since the consumption of radio resources for reporting event information is suppressed, the utilization efficiency of radio resources is improved.

  The method for suppressing event conditions related to unnecessary handover in the mobile station apparatus 1 connected to the base station apparatus 3 using one or a plurality of carrier elements by carrier aggregation has been described above. The applicable range is not limited to event conditions related to handover, but can also be applied to all event conditions notified from the base station apparatus 3 to the mobile station apparatus 1. The base station apparatus 3 can individually specify event conditions to be suppressed.

  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 storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a 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 the advancement of semiconductor technology, an integrated circuit based on the technology can 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.

DESCRIPTION OF SYMBOLS 1 Mobile station apparatus 3 Base station apparatus 101 Receiving part 103 Demodulating part 105 Decoding part 107 Upper layer 109 Encoding part 111 Modulating part 113 RS generating part 115 Multiplexing part 117 Transmitting part 119 Control part 201 Receiving part 203 Demodulating part 205 Decoding part 207 Measurement Processing unit 209 Event determination 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 225 Cell determination unit

Claims (4)

A communication system in which a base station apparatus and a mobile station apparatus perform communication using at least a first cell and a second cell selected from a plurality of cells,
The base station device
A reception quality comparison process performed by the mobile station apparatus, wherein an event trigger condition used for each measurement target cell that is a cell having the same frequency as the second cell and the event trigger condition A transmission unit for notifying the mobile station device of parameters used for evaluation;
The mobile station device
A receiver for receiving the event trigger condition and the parameter;
A cell determination unit that determines whether each of the cells to be measured is a cell to be evaluated for the event trigger condition;
An event determination unit for evaluating the event trigger condition,
The cell determination unit determines that the measurement target cell is not subject to the evaluation of the event trigger condition when the measurement target cell is a cell used for the communication. . A base station apparatus and a mobile station apparatus are mobile station apparatuses applied to a communication system that performs communication using at least a first cell and a second cell selected from a plurality of cells,
A reception quality comparison process performed by the mobile station apparatus, wherein an event trigger condition used for each measurement target cell that is a cell having the same frequency as the second cell and the event trigger condition A receiving unit for receiving parameters used for evaluation;
A cell determination unit that determines whether each of the cells to be measured is a cell to be evaluated for the event trigger condition;
An event determination unit for evaluating the event trigger condition,
The cell determination unit determines that the measurement target cell is not subject to the evaluation of the event trigger condition when the measurement target cell is a cell used for the communication. apparatus. An integrated circuit of a mobile station apparatus applied to a communication system in which a base station apparatus and a mobile station apparatus perform communication using at least a first cell and a second cell selected from a plurality of cells,
A reception quality comparison process performed by the mobile station apparatus, wherein an event trigger condition used for each measurement target cell that is a cell having the same frequency as the second cell and the event trigger condition Receive parameters used for evaluation,
Determining whether each of the cells to be measured is a cell to be evaluated for the event trigger condition;
Perform event determination to evaluate the event trigger condition,
An integrated circuit of a mobile station apparatus, wherein, when the measurement target cell is a cell used for the communication, the measurement target cell is determined not to be evaluated by the event trigger condition. A communication method in a mobile station apparatus applied to a communication system in which a base station apparatus and a mobile station apparatus perform communication using at least a first cell and a second cell selected from a plurality of cells,
The mobile station device
A reception quality comparison process performed by the mobile station apparatus, wherein an event trigger condition used for each measurement target cell that is a cell having the same frequency as the second cell and the event trigger condition Receive parameters used for evaluation,
Determining whether each of the cells to be measured is a cell to be evaluated for the event trigger condition;
Perform event determination to evaluate the event trigger condition,
A communication method, wherein, when the measurement target cell is a cell used for the communication, the measurement target cell is determined not to be evaluated by the event trigger condition.

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