JP4237162B2 - Channel identifier assigning method and mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption and time required for a mobile station to search peripheral cells, to decrease complications in design and management in a mobile communication system. <P>SOLUTION: A peripheral cells searching method using information sent from a sector to a mobile station in a mobile communication system that determines the sector for a mobile station communicating with several base stations to wait or communicate with a channel identifier received from the sector, pre-defines a mapping pattern mapping a sector number of the sector and the channel identifier number of the channel identifier so that one channel identifier is contained only in one mapping pattern, selects one mapping pattern per base station to assign the channel identifiers to each sector in the base station on the basis of the mapping pattern, and notifies mobile station in the scope of any one of the channel identifiers assigned to the peripheral base station sector for one peripheral base station from the base station. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a channel identifier assignment method, a mobile communication system, a mobile station, and a base station in a mobile communication system.

  A schematic diagram of a mobile communication system in the prior art will be described with reference to FIG.

  FIG. 1 is a diagram showing the concept of cells and sectors in the prior art.

  In wireless communication, a radio wave transmitted from a transmission end propagates while attenuating space and reaches a reception end. Propagation loss has the property of increasing as the distance between transmission and reception points increases. Therefore, when the distance between transmission and reception points increases, transmission power needs to be increased in order to obtain required reception quality, and power consumption increases. Reduction of power consumption is important for long-lasting battery and economy of system. Therefore, in a mobile communication system such as a mobile phone that is currently popularized, by installing a plurality of base stations in a service area, the area is made into a relatively small wireless zone called a cell (portion indicated by an ellipse in FIG. 1) The mobile station 20 communicates with the nearest base station 10 to reduce the distance between the transmission and reception points, thereby reducing power consumption. In addition, by providing a plurality of directional antennas in one base station 10 and dividing the cell into a plurality of sectors 30 (portions shown by sectors in FIG. 1), it is efficient without increasing the number of base station installation locations. To compensate for the propagation loss. At this time, it is important to select the best sector 30 in the mobile station 20 as the sector 30 that performs standby and communication.

  Here, the amount of attenuation in actual radio wave propagation varies greatly depending on the location because it is affected by the topography and other features in addition to the distance. Accordingly, as the mobile station 20 moves, the best sector 30 changes every moment. In such an environment, the mobile station 20 needs to search and capture peripheral sectors and monitor the radio wave propagation status so that the best sector 30 can always be selected. This search operation of the mobile station 20 is called a neighbor cell search. In the mobile station 20, being able to monitor the propagation status of as many sectors 30 as possible is important in always selecting the optimum sector 30.

  The neighboring cell search is performed by the mobile station 20 searching and receiving the perch channel transmitted from each sector 30. At this time, the perch channel of each sector 30 needs to have an identity to identify each channel so that it can be determined from which sector 30 the perch channel detected by the mobile station 20 is transmitted. Arise. Here, this identity is referred to as a “channel identifier”. A plurality of channel identifiers are prepared, a channel identifier is assigned to each sector 30, and a perch channel characterized by the channel identifier is transmitted from each sector 30. The channel identifier can have a high affinity with the system, for example, a carrier frequency for the TDMA / FDMA system, a spreading code for the CDMA system, and the like. When the mobile station 20 searches for a perch channel that can be received in the neighboring cell search and detects a new perch channel, the mobile station 20 identifies the channel identifier of the perch channel. As a result, the mobile station 20 can identify the sector 30, and determines the sector 30 that is waiting and performing communication based on the quality of the received perch channel.

  Here, when there is a sector 30 using the same channel identifier nearby, mutual influences such as erroneous recognition and erroneous detection of the sector 30 become a problem. If the sectors 30 to which the same channel identifier is assigned are sufficiently far away, the mutual influence can be suppressed to a sufficiently small level, and no problem occurs. Therefore, in a system in which the number of channel identifiers is smaller than the total number of sectors in the system and the same channel identifier needs to be repeatedly assigned to a plurality of sectors 30, it is necessary to pay close attention to the repetition interval. Here, if the number of channel identifiers is sufficiently large, repeated assignment becomes easy. However, as the number of channel identifiers increases, the number of candidates for channel identifier identification increases in the peripheral cell search, and the time required for the peripheral cell search increases. Therefore, from the viewpoint of speeding up the neighboring cell search, it is preferable that the number of channel identifiers is small.

  Here, even when the number of channel identifiers is large, the channel identifiers can be grouped in advance in order to perform a neighboring cell search at high speed. In a CDMA mobile communication system, as a technique for performing a neighboring cell search at a high speed when the number of channel identifiers, that is, a large number of spreading codes, a three-stage cell search technique is described in literature (Higuchi, Sawahashi, Adachi, “Fast Cell Search Algorithm”). in Inter-Cell Asynchronous DS-CDMA Mobile Radio, "IEICE Trans. Commun., Vol. E81-B, No. 7, July 1998). According to this technique, channel identifiers are grouped in advance, and when a mobile station performs a neighbor cell search, first the timing of the perch channel is detected, and then the group of channel identifiers is identified. Finally, by identifying channel identifiers belonging to the group, sectors can be identified more quickly. Performing the peripheral cell search at high speed is important in two respects: adapting to the state of propagation that changes with movement and reducing the power consumption required for the search. Even in the case of FDMA / TDMA, if carrier frequencies are grouped in advance, the frequency band to be swept during the peripheral cell search is limited, and the peripheral cell search can be speeded up.

  By the way, in each sector, the mobile station is notified of information related to the peripheral sector of the sector, and when the mobile station performs a peripheral cell search based on this information, the options for identifying the channel identifier are reduced, so that the peripheral cell is faster. The search can be completed. The mobile station can receive information on neighboring sectors from the sector in communication and the already captured sector. At this time, if the amount of information to be notified is large, the transmission power increases, and the power required for decoding by the mobile station also increases, which is not efficient. It is important to increase the accuracy of the peripheral cell search with less information.

  In such a mobile communication system, if the number of channel identifiers is increased from a request for repeated assignment of channel identifiers, the number of channel identifier candidates in the neighboring cell search increases, and thus the time required for neighboring cell search increases. .

  In addition, if the time required for the peripheral cell search increases, the power consumption of the search may increase, and it may not be able to cope with the changing propagation situation and the serious sector cannot be selected. Absent.

  Furthermore, if the best sector cannot be selected, the required transmission power increases, so that there are problems that interference to other users increases and power consumption increases.

  Furthermore, the mobile station usually receives information indicating which channel identifier is used in the peripheral sector from the sector where the mobile station is located, and performs a cell search based on this information. Since the channel identifiers of all the peripheral sectors are notified, there is a problem that power consumption increases and becomes inefficient.

  Furthermore, when the same channel identifier is repeatedly assigned to a plurality of sectors, it is necessary to pay attention to the repetition interval for each channel identifier, which causes a problem that the design and management become complicated.

  In view of the above problems, an object of the present invention is to reduce power consumption and time required for a mobile station to search for neighboring cells in a mobile communication system, and reduce design and management complexity. Another object of the present invention is to provide a channel identifier assignment method and a neighboring cell search method for each sector, a mobile communication system, and a base station and a mobile station constituting the system.

According to the first aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for performing standby or communication based on a channel identifier received from the sector. A method for searching neighboring cells using notified information, wherein a mapping pattern that associates a sector number of the sector and a channel identifier number of the channel identifier is included in only one mapping pattern. A step of selecting the mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and locating from the base station For each mobile base station, the base station Notifies any one of the channel identifier assigned to the serial sector, characterized in that it comprises a step.

The invention according to claim 2 is a method of searching for neighboring cells according to claim 1 , wherein one of the channel identifiers notified by the notifying step is one of the sectors in the neighboring base station. The channel identifier of the sector having the largest number of the mobile stations to be handed over from its own sector.

The invention according to claim 3 is a method of searching for neighboring cells according to claim 1 , wherein the information notified by the notifying step includes the sector number of the neighboring base station for each sector, and / or Alternatively, it includes a mapping pattern number of the mapping pattern to which the channel identifier number belongs.

According to a fourth aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector, from the sector to the mobile station. A method for searching neighboring cells using notified information, wherein a mapping pattern that associates a sector number of the sector and a channel identifier number of the channel identifier is included in only one mapping pattern. A step of selecting the mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and locating from the base station For each mobile base station, the base station Notifying one of the channel identifiers assigned to the sector, and preferentially searching for another channel identifier in the mapping pattern to which the channel identifier already captured by the mobile station belongs And a step.

According to a fifth aspect of the present invention, from the sector to the mobile station in a mobile communication system in which a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector. A method for searching neighboring cells using notified information, wherein a mapping pattern that associates a sector number of the sector and a channel identifier number of the channel identifier is included in only one mapping pattern. A step of selecting the mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and locating from the base station For each mobile base station, the base station Notifying one of the channel identifiers assigned to the sector, and the mapping pattern to which the channel identifier already captured by the mobile station belongs is an adjacent number in the channel identifier and a cyclic pattern. Preferentially searching for channel identifiers.

In a sixth aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector, and is notified from the sector to the mobile station. A mapping pattern for associating the sector number of the sector with the channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern. Means for selecting one mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and for the mobile station located from the base station The channel assigned to the sector of the peripheral base station per peripheral base station Characterized by comprising a means for notifying any one of identifiers.

A seventh aspect of the present invention is the mobile communication system according to the sixth aspect, wherein the one channel identifier notified by the notifying means is one of the sectors in the neighboring base station. The channel identifier of the sector having the largest number of mobile stations that are handed over from the sector.

The invention according to claim 8 is the mobile communication system according to claim 6 , wherein the information notified by the means for notifying includes the sector number of the neighboring base station for each sector and / or the A mapping pattern number of the mapping pattern to which the channel identifier number belongs is included.

According to the ninth aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector, and is notified from the sector to the mobile station. A mapping pattern for associating the sector number of the sector with the channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern. Means for selecting one mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and for the mobile station located from the base station The channel assigned to the sector of the peripheral base station per peripheral base station Means for notifying one of the identifiers, and means for preferentially searching for another channel identifier in the mapping pattern to which the channel identifier already captured by the mobile station belongs. And

According to the tenth aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector, and is notified from the sector to the mobile station. A mapping pattern for associating the sector number of the sector with the channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern. Means for selecting one mapping pattern for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and for the mobile station located from the base station The channel assigned to the sector of the peripheral base station per peripheral base station Preferentially searching for the channel identifier that becomes an adjacent number in a cyclic pattern with the channel identifier in the mapping pattern to which the channel identifier captured by the mobile station belongs. And a means for performing.

According to the eleventh aspect of the present invention, a mobile station that communicates with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector, and is notified from the sector to the mobile station. A mapping pattern that associates the sector number of the sector with the channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern. Means for selecting one of the mapping patterns for each base station, assigning the channel identifier to each sector in the base station according to the mapping pattern, and the mobile station located from the base station Assigned to the sector of the neighboring base station per neighboring base station Characterized by comprising a means for notifying any one of the serial channel identifier.

The invention according to claim 12 is the base station according to claim 11 , wherein one of the channel identifiers notified by the notifying means is one of the sectors in the neighboring base station. The channel identifier of the sector with the largest number of the mobile stations to be handed over from.

The invention according to claim 13 is the base station according to claim 11 , wherein the information notified by the means for notifying includes the sector number of the neighboring base station for each sector and / or the channel. The mapping pattern number of the mapping pattern to which the identifier number belongs is included.

The invention according to claim 14 is the mobile station of the mobile communication system according to any one of claims 6 to 10 , wherein the channel identifier is received from the base station and the means for recording the mapping pattern. And means for preferentially searching for another channel identifier in the mapping pattern to which the channel identifier received by the receiving means belongs.

A fifteenth aspect of the present invention is the mobile station of the mobile communication system according to any one of the sixth to tenth aspects, wherein the mapping identifier is recorded, and the channel identifier is received from the base station And a means for preferentially searching for the channel identifier that becomes an adjacent number by the cyclic pattern in the mapping pattern to which the channel identifier received by the receiving means belongs.

A sixteenth aspect of the present invention is the mobile communication system according to any one of the sixth , ninth, or tenth aspects, wherein the channel identifier is a spreading code or a carrier frequency.

The invention according to claim 17 is the method of searching for neighboring cells according to any one of claims 1, 4, or 5 , wherein the channel identifier is a spreading code or a carrier frequency. And

The invention according to claim 18 is the base station according to claim 11 , wherein the channel identifier is a spreading code or a carrier frequency.

The invention according to claim 19 is the mobile station according to claim 14 or 15 , wherein the channel identifier is a spreading code or a carrier frequency.

A twentieth aspect of the present invention is the mobile communication system according to the sixth aspect , the ninth aspect, or the tenth aspect of the present invention, wherein the channel identifier is included in a perch channel signal.

The invention according to claim 21 is a method of searching for neighboring cells according to any one of claims 1, 4, or 5 , wherein the channel identifier is included in a perch channel signal. To do.

The invention described in claim 22 is the base station described in claim 11 , wherein the channel identifier is included in a perch channel signal.

The invention according to claim 23 is the mobile station according to claim 14 or 15 , wherein the channel identifier is included in a perch channel signal.

(Effects of the first embodiment)
As will be described in detail below, according to the present invention, since the same group of channel identifiers are allocated to the same base station sector, when any one sector is captured by the mobile station, the base station to which the sector belongs The group of channel identifiers applied to other sectors of the station can be specified by the mobile station, and when searching for these sectors, the group to be searched by the mobile station is limited, so the time required for the peripheral cell search It is shortened and the effect that power consumption is reduced is acquired. In addition, since other sectors of the base station to which the captured sector belongs are powerful connection switching destination candidates from the geographical position, the mobile station waits and communicates that these sectors can be efficiently captured. The accuracy in always selecting the optimum sector as the sector is improved.

  Further, according to the present invention, since different groups of channel identifiers are assigned to sectors of adjacent base stations in the same system, the design complexity and management complexity when the same channel identifier is repeatedly assigned to a plurality of sectors are also increased. Is reduced.

  Furthermore, according to the present invention, in a mobile communication system in which the same group of channel identifiers are assigned to the same base station sector, only one channel identifier of the intra-base station sector is moved from each sector to one neighboring base station. Since the notification is made to the station, the amount of notification information can be reduced without reducing the efficiency of the neighboring cell search, and the power consumption can be reduced.

(Effect of the second embodiment)
Also, according to the present invention, a plurality of mapping patterns of sector numbers and control channel numbers are defined in advance by the system, and control channels are allocated to each sector according to any pattern for each base station. When one sector is acquired, a control channel applied to another sector of the base station to which the sector belongs can be specified by referring to a mapping pattern known to the mobile station. When searching for these sectors, the control channel to be searched by the mobile station is limited, so that the time required for the peripheral cell search is shortened and the power consumption is reduced. In addition, since other sectors of the base station to which the captured sector belongs are powerful connection switching destination candidates from the geographical position, the mobile station waits and communicates that these sectors can be efficiently captured. The accuracy in always selecting the optimum sector as the sector is improved.

  Further, according to the present invention, since different patterns are assigned to adjacent base stations, the complexity and management complexity in the case of repeatedly assigning the same control channel to a plurality of sectors are reduced.

  Further, according to the present invention, only one control channel of each sector in the base station is notified to each mobile station from each sector, or a control channel mapping pattern used in each base station from each sector. Since the number is notified, the amount of notification information can be reduced without reducing the efficiency of the peripheral cell search, and the power consumption can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 2 is a schematic diagram illustrating an example of the mobile communication system according to the first embodiment.

  In FIG. 2, attention is paid only to three adjacent cells from among a plurality of cells constituting the mobile communication system. In FIG. 2, black dots indicate the base station 10, and BS1 to BS3 indicate base station names. Each cell is divided into six sectors, and a channel identifier is assigned to each sector. In FIG. 2, “G” indicates a channel identifier group, and “C” indicates a channel identifier number. For example, since sector 1 of BS1 has “G1, C16”, a channel identifier of number 16 belonging to group 1 is assigned. In this embodiment, channel identifier numbers 1 to 19 are grouped in advance in group 1, channel identifier numbers 20 to 29 in group 2, and channel identifiers 30 to 39 are grouped in advance. The division information is assumed to be known. The grouping may be performed in any manner as long as it is uniquely determined by the system, and is not limited to the present embodiment. Also, the number of sectors does not have to be 6, and may be another number of sectors. Here, the same group of channel identifiers are assigned to sectors in the same base station. Referring to FIG. 2, for example, any one of channel identifiers 1 to 19 of group 1 is allocated to sectors 1 to 6 of BS1, and channel identifiers of other groups are not allocated. In the mobile station of FIG. 2, it is assumed that sector 5 of BS1 and sector 2 of BS3 have already been captured. It is known that the channel identifier C18 of BS1 sector 5 belongs to group 1 in the mobile station. Therefore, in the mobile station, it can be determined that the channel identifier of group 1 is assigned to each sector of BS1. Similarly, it can be determined that the channel identifier of group 3 is assigned to each sector of BS3. At this time, there is a high possibility that new sectors 4 and 6 of BS1 and sectors 1 and 3 of BS3 can be newly acquired by the neighboring cell search from the geographical positional relationship. Therefore, in the neighboring cell search, if the groups 1 and 3 are searched preferentially, new sectors can be efficiently captured. Thus, when searching for a new sector, the group to be searched is limited, and the number of channel identifier candidates at the time of identification is limited to a small number, so that the search time can be greatly shortened.

  Sectors in the same base station have substantially the same amount of attenuation in radio wave propagation because the antenna positions are substantially the same. Therefore, if any one sector can be acquired in the mobile station, there is a high possibility that other sectors in the same base station can also be acquired. Therefore, if a channel identifier belonging to the same group as the acquired channel identifier is preferentially searched, a new sector can be acquired efficiently. As described above, since the time required for the neighboring cell search is shortened, the accuracy of selecting the optimum sector as a sector for standby and communication can be improved, and power consumption can be reduced.

  Also, different groups of channel identifiers are assigned to adjacent base station sectors, but in a mobile communication system with a large number of sectors, such as mobile phones, the same channel identifier is repeatedly assigned to distant sectors that have a sufficiently small influence. There is a need. At this time, if there are sectors to which the same channel identifier is assigned nearby, mutual influences such as erroneous sector recognition and erroneous detection become a problem. Here, it is complicated in design and management to pay attention to the repetition interval for each channel identifier. By applying the present invention, design and management can be facilitated because it is sufficient to consider the repetition interval in units of base stations and groups, not in units of sectors and channel identifiers.

  Moreover, the sector 5 of BS1 may notify the mobile station of the channel identifier number of any one sector of BS3 as the channel identifier information of BS3. Here, it is free to determine which sector's channel identifier number of BS3 is, but the most effective is to select the sector of BS3 having the most mobile stations to be handed over from its own sector. Therefore, if the sector of BS3 with the most mobile stations to be handed over from sector 5 of BS1 is, for example, sector 2 of BS3, the channel identifier number of sector 2 of BS3 may be notified in sector 5 of BS1. Similarly, if the sector of BS2 with the largest number of mobile stations to be handed over from sector 5 of BS1 is sector 3 of BS2, the channel identifier number of sector 3 of BS2 may be notified in sector 5 of BS1. Therefore, in the present embodiment, the peripheral sector information broadcast from the sector 5 of the BS 1 is only the channel identifier numbers C39 and C23. As described above, even when the notification information is reduced only to the channel identifier numbers of the sectors with the largest number of mobile stations to be handed over from its own sector, the mobile station only obtains the information C39 and C23 from the sectors 5 of BS1, It can be known that there is a base station to which group 3 is assigned and a base station to which group 2 is assigned. Therefore, if the group 3 and the group 2 are preferentially searched in the peripheral cell search, the peripheral cell search can be speeded up because, for example, the group identification can be speeded up. At this time, not only the sector of the channel identifier included in the notification information but also other sectors belonging to the same base station as the sector are easily captured because of the same group. In addition, when the channel identifier number of the sector of the adjacent base station with the largest number of mobile stations to be handed over from its own sector is notified, the mobile station efficiently searches for peripheral sectors that have a high probability of being received by preferentially searching for this channel identifier. It is most effective because it can be captured.

  In the present embodiment, a plurality of groups of channel identifiers may be assigned to sectors of the same base station. For example, if the number of base station sectors is greater than the number of channel identifiers in the group, the channel identifiers of the same base station sectors cannot all be made the same group. In this case, if the base station is divided into a plurality, a subset of the sectors in the base station is created, one created subset is regarded as one base station, and the other subset is regarded as an adjacent base station, Similarly, the present invention can be applied.

  FIG. 3 is a diagram illustrating an example of a configuration of a base station to which the first embodiment of the present invention is applied, and conceptually illustrates only a portion related to the present invention in the configuration of the base station.

  The base station 10 includes at least a user interface 302, a notification information setting control unit 304, a channel identifier setting control unit 306, a notification information storage unit 308, a channel identifier generation unit 310, a perch channel information configuration unit 312, a modulation unit 314, and a multiplexing unit. 316, an amplification unit 318, an antenna 320, another channel signal processing unit 322, and a network interface 324. The user interface 302 is connected to the notification information setting control unit 304 and the channel identifier setting control unit 306 and has a man-machine interface function between the operator and the base station 10. The notification information setting control unit 304 is connected to the notification information storage unit 308 corresponding to each sector, and has a function of controlling the setting of notification information for each sector. Here, the “notification information” is information for the base station to notify the mobile station located in each sector based on the method described with reference to FIG. 2, for example, neighboring cells corresponding to each sector. Channel identifier, group number, and the like. The channel identifier setting control unit 306 is connected to the channel identifier generation unit 310 corresponding to each sector, selects and sets a channel identifier number assigned to each sector input via the user interface 302 from the same group, and sets the channel identifier. It has a function of controlling the generator 310. The notification information storage unit 308 has a function of storing notification information set by the notification information setting control unit 304 for each sector and transmitting notification information corresponding to each sector to the perch channel information configuration unit 312. The channel identifier generation unit 310 has a function of generating a channel identifier corresponding to each sector and transmitting the channel identifier to the modulation unit 314. Here, the “channel identifier” may be, for example, a carrier frequency in the case of the TDMA / FDMA system, or may be, for example, a spreading code in the case of the CDMA system. The perch channel information configuration unit 312 has a function of configuring perch channel information based on the notification information received from the notification information storage unit 308 and transmitting it to the modulation unit 314. The modulation unit 314 has a function of inputting and modulating the perch channel information configured in the perch channel information configuration unit 312 and the channel identifier generated by the channel identifier generation unit 310. For example, if the channel identifier is a spreading code, the perch channel signal is spread-modulated with the spreading code that is the channel identifier, and if the channel identifier is the carrier frequency, the carrier frequency carrier wave that is the channel identifier is the perch channel signal. Modulate. The multiplexing unit 316 has a function of multiplexing the signal modulated by the modulation unit 314 and the other channel signal processed by the other channel signal processing unit 322. The amplifying unit 318 is connected to the antenna 320 and has a function of amplifying a signal. The antenna 320 has a function of performing communication with a mobile station. The other channel signal processing unit 322 is connected to the network interface 324 and has a function of processing other channel signals and transmitting them to the multiplexing unit 316. The network interface 324 has an interface function for connection with a host network.

  Next, an example of the operation of the base station in the first embodiment configured as described above will be described below.

  First, the channel identifier assigned to each sector by the operator via the user interface 302 is selected from the same group and set for each sector.

  Next, the channel identifier setting control unit 306 notifies the channel identifier generation unit 310 of each sector which number of the identifier is generated, and the channel identifier generation unit 310 generates a channel identifier corresponding to this number. .

  Next, each sector including notification information such as a channel identifier number and a group number of a neighboring cell, which is set in the notification information setting control unit 304 via the user interface 302 and stored in the notification information storage unit 308 for each sector. The perch channel information is characterized by a channel identifier in modulation section 314.

  Next, multiplexing section 316 multiplexes with other channel signals, and amplification section 318 transmits the amplified signal from antenna 320 to the mobile station after amplification.

  In the present embodiment, the notification information is configured such that the user sets channel identifier numbers and group numbers of neighboring cells for each sector or each base station via the user interface 302. However, even if the notification information is not set by the user, it receives the statistical results of the peripheral sectors with the most mobile stations handed over from its own sector via the network and automatically notifies the channel identifier numbers of these peripheral sectors. The information may be set in each sector. Further, the notification information need not be included in the perch channel information, and may be superimposed on other channels (such as individual communication channels for each user).

(Second Embodiment)
FIG. 4 is a schematic diagram showing an example of a mobile communication system according to the second embodiment of the present invention.
FIG. 4 focuses on only three adjacent cells among many cells constituting the mobile communication system. In FIG. 4, black dots represent the base station 10, and BS1 to BS3 represent base station names. Each cell is divided into six sectors, and a channel identifier is assigned to each sector. The channel identifier number and the sector number are mapped in advance according to a plurality of patterns defined by the system, and all the patterns are known to the mobile station.

  In the present embodiment, it is assumed that the mapping pattern is defined as shown in FIG. 4 and 5, “C” indicates a channel identifier number. In FIG. 5, for example, the column “C1” means that the channel identifier C1 is assigned to the sector 1 in the base station to which the pattern 1 is applied. Here, the mapping pattern is configured so that the same channel identifier does not appear redundantly in a plurality of patterns, and one channel identifier is included only in one pattern.

  Each base station assigns a channel identifier to a sector in the base station according to any pattern shown in FIG. The case of FIG. 4 will be described as an example. Pattern 1 is applied to BS1, pattern 3 is applied to BS2, and pattern 7 is applied to BS3. Channel identifiers are assigned to sectors in each base station according to each pattern. In the present embodiment, the number of sectors is 6, as shown in FIG. 4, but the present invention is not limited to this case, and any number of sectors may be used. Further, the mapping pattern is not limited to the example of the table shown in FIG. 5, and it is obvious to those skilled in the art that any arbitrary pattern can be taken. For example, ascending order may be used as in patterns 1, 2, 3, and 5 in FIG. Moreover, it is good also as a pattern without regularity like the pattern 4,6,8. In the mapping pattern of FIG. 5, pattern 1 can be applied to a base station having 10 or less sectors, and pattern 2 can be applied to a base station having 4 or less sectors.

  Here, in mobile station 20 shown in FIG. 4, it is assumed that sector 5 of BS1 and sector 2 of BS3 have already been acquired, that is, channel identifiers C5 and C48 have been acquired. As described above, since it is known that the channel identifier C5 belongs to pattern 1 in the mobile station, it can be determined that pattern 1 is applied to BS1. Similarly, it can be determined that pattern 7 is applied to BS3. Here, there is a high possibility that a sector adjacent to two captured sectors can be captured from the geographical positional relationship. Therefore, if the channel identifiers of C4 and C6 adjacent to C5 in pattern 1 and C49 and C47 adjacent to C48 in pattern 7 are searched preferentially, a new sector with a high probability of being received can be efficiently captured. Cell search can be made efficient.

  Sectors in the same base station have substantially the same amount of attenuation in radio wave propagation because the antenna positions are substantially the same. Therefore, if any one sector can be acquired in the mobile station, there is a high possibility that other sectors of the same base station, particularly sectors adjacent to the acquired sector can also be acquired. Therefore, if the allocation method shown in the present embodiment is used, the number of channel identifier candidates in the neighboring cell search can be greatly reduced. In addition, if a channel identifier other than the pattern to which the captured channel identifier belongs is preferentially searched, a new sector can be efficiently captured. In addition, if a channel identifier having a number adjacent to a channel identifier number that has already been acquired is preferentially searched for in the cyclic pattern of the pattern to which the channel belongs, a new sector can be acquired more efficiently. Here, the “circular pattern” means that, for example, in the pattern 1 of FIG. 5, when the channel identifier C1 already assigned to the sector 1 is already captured by the mobile station, the cyclic pattern is adjacent in addition to the adjacent C2. This means that C10 is also preferentially searched. As described above, since the time required for the peripheral cell search is shortened, the accuracy in selecting the optimum sector as the sector for standby and communication can be improved, and the power consumption can be reduced.

  Further, in a mobile communication system having a large number of sectors such as a mobile phone, it is necessary to repeatedly assign the same channel identifier to distant sectors that have a sufficiently small influence. At this time, if there are sectors to which the same channel identifier is assigned nearby, mutual influences such as erroneous sector recognition and erroneous detection become a problem. Here, assigning each channel identifier while paying attention to the repetition interval is complicated in terms of design and management. Therefore, in this embodiment, channel identifiers may be assigned to sectors of the same base station according to different mapping patterns. By assigning channel identifiers to adjacent base station sectors according to different mapping patterns, it is only necessary to consider the repetition interval in units of base stations and patterns, not in units of sectors or channel identifiers. Can be made easier.

  Moreover, the sector 5 of BS1 may notify the channel identifier number of any one sector of BS3 as channel identifier information of BS3. The sector identifier of BS3 can be broadcasted freely, but the most effective is to set the sector of BS3 with the most mobile stations to be handed over from the notified sector. Therefore, if the sector of BS3 with the most mobile stations to be handed over from sector 5 of BS1 is, for example, sector 2 of BS3, the channel identifier number of sector 2 of BS3 may be notified in sector 5 of BS1. Similarly, if the sector of BS2 with the largest number of mobile stations to be handed over from sector 5 of BS1 is sector 3 of BS2, the channel identifier number of sector 3 of BS2 may be notified in sector 5 of BS1. Therefore, in the present embodiment, the peripheral sector information broadcast from the sector 5 of the BS1 is only the channel identifier numbers C48 and C23. As described above, even when the notification information is reduced to only C48 and C23, the mobile station 20 only obtains information of C48 and C23 from the sector 5 of BS1, and there are base stations of pattern 3 and pattern 7 around. I can know that. Further, channel identifier numbers used in each sector of those base stations can be estimated from the patterns. Therefore, even when not reporting the channel identifiers of all the peripheral sectors, it is sufficient to know the channel identifier numbers of the peripheral sectors with the minimum notification information. Thereby, the amount of notification information can be reduced without reducing the accuracy of the peripheral cell search, and the power consumption can be reduced. Here, even if the channel identifier number of any sector of the neighboring base station is notified, the mobile station can perform pattern identification, so that a sufficient effect can be obtained. However, as described above, the adjacent base station with the largest number of mobile stations to be handed over If the channel identifier number of the sector is notified, it is most effective because the perch channel of the peripheral sector having a high probability of being received can be efficiently acquired by preferentially searching for this channel identifier in the mobile station.

  In the present embodiment, the notification information is the channel identifier number, but the same effect can be obtained by notifying the pattern number of the neighboring base station. That is, each sector notifies the mobile station of the pattern number applied to the peripheral base station, and the mobile station performs a peripheral cell search based on this notification information. The mobile station only needs to preferentially search for a channel identifier belonging to the notified pattern, and the probability of efficiently acquiring a new sector increases. Therefore, the time required for the peripheral cell search can be shortened and the power consumption can be reduced.

  Further, the present embodiment is characterized in that one mapping pattern is selected for each base station and a channel identifier is assigned. Here, when the number of sectors of the base station is larger than the number of channel identifiers constituting the pattern, it is impossible to assign to all sectors of the same base station in one pattern. In this case, if the base station is divided into a plurality, a subset of the sectors in the base station is created, one created subset is regarded as one base station, and the other subset is regarded as an adjacent base station, Similarly, the present invention can be applied.

  FIG. 6 is a diagram illustrating an example of a configuration of a base station to which the second embodiment of the present invention is applied, and conceptually illustrates only a portion related to the present invention in the configuration of the base station.

  The base station 10 includes at least a user interface 302, a notification information setting control unit 304, a pattern number storage unit 305, a channel identifier setting control unit 306, a mapping pattern table 307, a notification information storage unit 308, a channel identifier generation unit 310, and perch channel information. The configuration unit 312, the modulation unit 314, the multiplexing unit 316, the amplification unit 318, the antenna 320, the other channel signal processing unit 322, and the network interface 324 are configured. Here, the pattern number storage unit 305 is connected to the user interface 302 and the channel identifier setting control unit 306 and has a function of storing a pattern number input by the user via the user interface 302. Further, the mapping pattern table 307 is a table that stores, for example, the mapping pattern as shown in FIG. In addition, since the part which attached | subjected the code | symbol same as FIG. 5 in other parts has the same function in FIG. 6, description is abbreviate | omitted.

  Next, the operation of the base station in this embodiment configured as described above will be described below.

  First, the operator sets a mapping pattern number to be assigned to the base station from the user interface 302 and stores it in the pattern number storage unit 305.

  Next, the channel identifier setting control unit 306 refers to the mapping pattern table 307 to check the channel identifier assigned to each sector, and notifies the channel identifier generation unit 310 of each sector of the channel identifier number.

  Next, the channel identifier generator 310 generates a channel identifier corresponding to this number.

  Next, the perch channel information of each sector is characterized by these channel identifiers in the modulation unit 314.

  Next, the signal is multiplexed with another channel signal in multiplexing section 316, amplified in amplification section 318, and then transmitted from antenna 320 to the mobile station.

  In FIG. 6, the notification information is configured such that the user sets the channel identifier number and pattern number of the neighboring cell for each sector or each base station, for example. However, even if the notification information is not set by the user, it receives the statistical results of the peripheral sectors with the most mobile stations handed over from its own sector via the network and automatically notifies the channel identifier numbers of these peripheral sectors. The information may be set in each sector. Further, the notification information need not be included in the perch channel information, and may be superimposed on other channels (such as individual communication channels for each user).

(Configuration of mobile station)
Hereinafter, the mobile station used in the above-described embodiment of the present invention will be described in detail with reference to FIG.

  FIG. 7 is a diagram showing an example of the configuration of the mobile station of the mobile communication system in the above-described embodiment of the present invention, and conceptually shows only the portion related to the present invention in the configuration of the mobile station.

  The mobile station 20 includes at least an antenna 702, a channel identifier search unit 706, a radio reception unit 704, a control unit 710, and a memory unit 712. The antenna 702 is connected to the channel identifier search unit 706 and the radio reception unit 704 and has a function of receiving radio waves transmitted from the base station 10. The channel identifier search unit 706 is connected to the antenna 702, the control unit 710, and the radio reception unit 704, and has a function of searching for a channel identifier from a signal received via the antenna 702, and controls the captured channel identifier. 710 and a function of reporting to the wireless reception unit 704. The wireless reception unit 704 decodes the notification information from the sector using the channel identifier from the signal received via the antenna 702, and decodes the channel identifier and group of the decoded peripheral sector. And a function of reporting a mapping pattern or the like to the control unit 710. The control unit 710 is connected to the channel identifier search unit 706, the wireless reception unit 704, and the memory unit 712, and records the captured channel identifier and the channel identifiers of peripheral sectors in the memory unit 712, and then searches for the next. A function to control the channel identifier search unit 706 to preferentially search for the channel identifier by selecting a channel identifier to be selected. The memory unit 712 is connected to the control unit 710 and has a memory function of storing a captured channel identifier, a channel identifier of a peripheral sector based on notification information received from the base station 10, a group of channel identifiers, and a mapping pattern.

  Next, the operation of the mobile station 20 configured as described above will be described below.

  First, when the channel identifier search unit 706 newly captures a channel identifier from the received signal, the control unit 710 registers the channel identifier of the sector in the memory unit 712 as the captured channel identifier.

  Next, the channel identifier search unit 706 reports the channel identifier of the sector to the radio reception unit 704.

  Next, the wireless reception unit 704 decodes the notification information from the sector using the channel identifier captured in the channel identifier from the signal received via the antenna 702, and reports the result to the control unit 710. .

  Next, the control unit 710 registers the notification information, that is, channel identifiers, groups, mapping patterns, and the like of peripheral sectors in the memory unit 712.

  Next, the control unit 710 uses a channel identifier reported from the channel identifier search unit 706 and a channel identifier of a peripheral sector reported from the wireless reception unit 704 as a determination material in advance to determine a channel identifier that is likely to be captured in the future. select. At this time, both the channel identifier reported from the channel identifier search unit 706 and the channel identifier reported from the radio reception unit 704 can be prioritized in the determination. For example, the channel reported from the channel identifier search unit 706 A channel that is prioritized by the identifier, searches for a channel identifier group and mapping pattern to which the channel identifier belongs, is selected from the memory unit 712 as a channel identifier that is likely to be preferentially captured in the future, and is reported from the radio reception unit 704 The identifier may be positioned as the next priority.

  Next, the control unit 710 controls the channel identifier search unit 706 to preferentially search for a channel identifier that is likely to be captured in the future. As a result, when the mobile station 20 performs a neighbor cell search, the groups to be searched by the mobile station 20 are limited, so that the time required for the neighbor cell search is shortened and power consumption is reduced. It is done. In addition, since the other sectors of the base station 10 to which the captured sector belongs are powerful connection switching destination candidates from the geographical position relationship, the mobile station 20 waits for communication between these sectors and that the sector can be efficiently captured. The accuracy in selecting the optimum sector at all times as the sector to be performed is improved.

It is a figure which shows the concept of the cell and sector in a prior art. It is a schematic diagram explaining an example of the mobile communication system which concerns on 1st Embodiment. It is a figure which shows an example of a structure of the base station to which the 1st Embodiment of this invention is applied. It is a schematic diagram which shows an example of the mobile communication system which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the mapping pattern which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the base station to which the 2nd Embodiment of this invention is applied. It is a figure which shows an example of a structure of the mobile station to which this invention is applied.

Explanation of symbols

10 base station 20 mobile station 30 sector 302 user interface 304 notification information setting control unit 305 pattern number storage unit 306 channel identifier setting control unit 307 mapping pattern table 308 notification information storage unit 310 channel identifier generation unit 312 perch channel information configuration unit 314 modulation Unit 316 multiplexing unit 318 amplifying unit 320 antenna 322 other channel signal processing unit 324 network interface 702 antenna 704 wireless reception unit 706 channel identifier search unit 710 control unit 712 memory unit

Claims (23)

Peripheral cell using information notified from the sector to the mobile station in a mobile communication system in which a mobile station communicating with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector A method of searching for
Pre-determining a mapping pattern associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern;
Selecting one of the mapping patterns for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station located from the base station. A method of searching for neighboring cells. A method for searching for neighboring cells according to claim 1 , comprising:
One of the channel identifiers notified by the notifying step is the channel identifier of the sector having the largest number of the mobile stations to be handed over from one of the sectors in the neighboring base station. To search for neighboring cells. A method for searching for neighboring cells according to claim 1 , comprising:
The information notified by the notifying step includes the sector number of the neighboring base station for each sector and / or the mapping pattern number of the mapping pattern to which the channel identifier number belongs. How to search. Peripheral cell using information notified from the sector to the mobile station in a mobile communication system in which a mobile station communicating with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector A method of searching for
Pre-determining a mapping pattern associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern;
Selecting one of the mapping patterns for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station residing from the base station;
Preferentially searching for other channel identifiers in the mapping pattern to which the channel identifiers already captured by the mobile station belong. Peripheral cell using information notified from the sector to the mobile station in a mobile communication system in which a mobile station communicating with a plurality of base stations determines a sector for standby or communication based on a channel identifier received from the sector A method of searching for
Pre-determining a mapping pattern associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included in only one mapping pattern;
Selecting one of the mapping patterns for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station residing from the base station;
Searching neighboring cells, comprising preferentially searching for the channel identifier that becomes an adjacent number in a cyclic pattern in the mapping pattern to which the channel identifier captured by the mobile station belongs. Method. In a mobile communication system using a channel identifier received from a sector, a mobile station communicating with a plurality of base stations determines a sector for standby or communication, and uses information notified from the sector to the mobile station There,
Means for determining in advance a mapping pattern for associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included only in one mapping pattern;
Means for selecting one mapping pattern for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Means for notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station located from the base station. A mobile communication system. The mobile communication system according to claim 6 , wherein
One of the channel identifiers notified by the notifying means is the channel identifier of the sector having the largest number of mobile stations to be handed over from one of the sectors in the neighboring base station. Mobile communication system. The mobile communication system according to claim 6 , wherein
The information notified by the means for notifying includes the sector number of the neighboring base station for each sector and / or the mapping pattern number of the mapping pattern to which the channel identifier number belongs. . In a mobile communication system using a channel identifier received from a sector, a mobile station communicating with a plurality of base stations determines a sector for standby or communication, and uses information notified from the sector to the mobile station There,
Means for determining in advance a mapping pattern for associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included only in one mapping pattern;
Means for selecting one mapping pattern for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Means for notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station located from the base station;
Means for preferentially searching for another channel identifier in the mapping pattern to which the channel identifier already captured by the mobile station belongs. In a mobile communication system using a channel identifier received from a sector, a mobile station communicating with a plurality of base stations determines a sector for standby or communication, and uses information notified from the sector to the mobile station There,
Means for determining in advance a mapping pattern for associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included only in one mapping pattern;
Means for selecting one mapping pattern for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Means for notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station located from the base station;
Means for preferentially searching for the channel identifier that becomes an adjacent number in a cyclic pattern in the mapping pattern to which the channel identifier captured by the mobile station belongs. A mobile communication system that uses a channel identifier received from a sector to determine a sector on which a mobile station that communicates with a plurality of base stations waits or communicates and uses information notified from the sector to the mobile station A base station,
Means for determining in advance a mapping pattern for associating a sector number of the sector with a channel identifier number of the channel identifier so that one channel identifier is included only in one mapping pattern;
Means for selecting one mapping pattern for each base station and assigning the channel identifier to each sector in the base station according to the mapping pattern;
Means for notifying one of the channel identifiers assigned to the sector of the neighboring base station per neighboring base station to the mobile station located from the base station. Feature base station. The base station according to claim 11 , wherein
One of the channel identifiers notified by the notifying means is the channel identifier of the sector having the largest number of mobile stations to be handed over from one of the sectors in the neighboring base station. Base station. The base station according to claim 11 , wherein
The base station characterized in that the information notified by the means for notifying includes the sector number of the neighboring base station for each sector and / or the mapping pattern number of the mapping pattern to which the channel identifier number belongs. A mobile station of the mobile communication system according to any one of claims 6 to 10 ,
Means for recording the mapping pattern;
Means for receiving the channel identifier from the base station;
Means for preferentially searching for another channel identifier in the mapping pattern to which the channel identifier received by the receiving means belongs. A mobile station of the mobile communication system according to any one of claims 6 to 10 ,
Means for recording the mapping pattern;
Means for receiving the channel identifier from the base station;
And a means for preferentially searching for the channel identifier that becomes an adjacent number in the cyclic pattern in the mapping pattern to which the channel identifier received by the receiving means belongs. A mobile communication system according to claim 6 , claim 9 or claim 10 ,
The mobile communication system, wherein the channel identifier is a spreading code or a carrier frequency. A method for searching for neighboring cells according to any one of claims 1, 4 or 5 , comprising:
A method for searching for neighboring cells, wherein the channel identifier is a spreading code or a carrier frequency. The base station according to claim 11 , wherein
The base station, wherein the channel identifier is a spreading code or a carrier frequency. A mobile station according to claim 14 or claim 15 ,
The mobile station characterized in that the channel identifier is a spreading code or a carrier frequency. A mobile communication system according to claim 6 , claim 9 or claim 10 ,
The mobile communication system, wherein the channel identifier is included in a perch channel signal. A method for searching for neighboring cells according to any one of claims 1, 4 or 5 , comprising:
A method for searching neighboring cells, wherein the channel identifier is included in a perch channel signal. The base station according to claim 11 , wherein
The base station, wherein the channel identifier is included in a perch channel signal. A mobile station according to claim 14 or claim 15 ,
The mobile station, wherein the channel identifier is included in a perch channel signal.

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