JP5002416B2 - Radio frame control apparatus, radio frame control method, and radio communication apparatus - Google Patents

Description

  The present invention relates to a radio frame control device, a radio frame control method, and a radio communication device.

  As a next-generation wireless access system, IEEE (Institute of Electrical and Electronic Engineers) standard IEEE 802.16 is known to realize high-speed and wideband transmission (see, for example, Non-Patent Document 1). In the IEEE 802.16 standard, an Orthogonal Frequency Division Multiple Access (OFDMA) system is adopted as one of transmission systems. The OFDMA scheme is one of multicarrier transmission schemes in which communication is performed using a wideband signal composed of a plurality of subcarriers whose frequencies are orthogonal to each other, and by using different subcarriers for each user (terminal station). Realize multiple access between one base station and multiple users. Further, as an extension of the IEEE 802.16 standard, a standard IEEE 802.16e corresponding to a mobile communication environment is defined (for example, see Non-Patent Document 2). Similarly, the IEEE 802.16e standard adopts the OFDMA system as one of the transmission systems.

  FIG. 9 is a diagram illustrating a conventional configuration example of a radio frame (hereinafter referred to as “uplink subframe”) of an OFDMA uplink (link from a terminal station to a base station). The uplink subframe in FIG. 9 is compliant with the IEEE 802.16 and IEEE 802.16e standards (hereinafter, both standards are referred to as IEEE 802.16 standards). In FIG. 9, the uplink subframe is composed of a plurality of orthogonal frequency division multiple access symbols (OFDMA symbols) and a plurality of logical subchannels (Logical subchannels). In the uplink subframe, a plurality of OFDMA symbols are multiplexed in the time direction over an uplink subframe period. In addition, a plurality of subchannels are frequency-multiplexed within the OFDMA symbol. In the OFDMA scheme, arrangement information indicating in which logical subchannel of which OFDMA symbol a packet from each user is arranged is determined for each uplink subframe. The base station notifies each terminal station of the determined arrangement information on downlink communication. The transmitter of each terminal station performs uplink packet transmission using the logical subchannel specified by the notified arrangement information.

  Note that uplink packets from each terminal station arranged in the logical subchannel are transmitted after being rearranged in the frequency direction during actual transmission. In the IEEE 802.16e standard, the rearrangement pattern is specified by a variable called uplink palm base (UL_PermBase). The uplink palm base is determined to specify a value from 0 to 69, and the rearrangement pattern differs depending on the value. Each terminal station performs transmission after converting the data arranged in the logical subchannel with the pattern according to the value of the uplink palm base on the actual frequency.

  FIG. 9 shows a partial usage of subchannel (PUSC) zone of an uplink subframe such as the IEEE 802.16 standard. As shown in the figure, a ranging subchannel and an uplink burst (UL burst) are arranged in the uplink subframe. The ranging subchannel is a part that stores a signal for transmitting a connection request when the terminal station goes to the base station or transmitting a bandwidth request after connection. The uplink burst is a part for storing an actual communication packet, and one uplink burst is composed of uplink packets from one terminal station. The size of the uplink burst can be arbitrarily determined within the limits defined by the IEEE 802.16 standard or the like. In the example of FIG. 9, five uplink bursts, that is, five uplink bursts are provided. The provision method is based on the IEEE 802.16 standard.

  FIG. 10 is an example showing the relationship between the location information notified to the terminal station side by the prior art and the uplink burst on the radio frame. As shown in FIG. 10, the arrangement information is composed of information including three items: a communication identifier, a modulation scheme and a coding rate (PHY_MODE), and a resource amount allocated to the communication and usable for packet transmission. The amount of resources for one communication identifier in the arrangement information corresponds to the definition of one uplink burst on the radio frame.

  In the IEEE 802.16 standard or the like, a method of assigning OFDMA symbols and subcarriers in an uplink subframe, that is, a method of providing an uplink burst is defined. According to the regulations, as in the burst configuration shown in uplink burst # 2 in FIG. 9, one burst secures resources in order from the smallest logical subchannel number, and in one logical subchannel, the time direction A resource must be secured in the (OFDMA symbol direction), the resource must be secured following the end of the previous burst, and a packet must be allocated in that resource.

  That is, the resource used by each communication indicated by the communication identifier in the arrangement information must be secured from the resource immediately after the resource used by the previous communication in the order indicated by the arrangement information. The amount of resources used by each communication corresponds to the resource amount specified by the arrangement information. These two pieces of information determine the location and size of each uplink burst.

For example, in FIG. 10, the communication with the communication identifier 1 is the next channel of the first logical subchannel secured by the ranging subchannel, because 11 slots are allocated as the amount of resources that can be used. Packets are transmitted using the first slot of the No. 4 logical subchannel to the third slot of the No. 4 logical subchannel. Since the communication of communication identifier 2 is assigned 14 slots as the amount of resources that can be used, the eighth logic from the fourth slot of the fourth logical subchannel immediately after the resource used by the communication of communication identifier 1 is assigned. Packets are transmitted using up to the first slot of the subchannel. Since the communication with the communication identifier 3 is assigned 19 slots as the amount of resources that can be used, the 12th logical from the second slot of the 8th logical subchannel immediately after the resource used by the communication with the communication identifier 2 Packets are transmitted using up to the last slot of the subchannel. Since the communication with the communication identifier 4 is assigned 14 slots as the amount of resources that can be used, the 16th logical sub-channel from the first slot of the 13th logical sub-channel immediately after the resource used by the communication with the communication identifier 3 is used. Packets are transmitted using up to the second slot of the channel. Since communication of communication identifier 5 is assigned 14 slots as the amount of resources that can be used, the 19th logic from the third slot of the 16th logical subchannel immediately after the resource used by the communication of communication identifier 4 Packets are transmitted using up to the last slot of the subchannel.
IEEE Std 802.16-2004, “Air Interface for Fixed Broadband Wireless Access Systems,” 2004. IEEE Std 802.16e-2005, “Air Interface for Fixed Broadband Wireless Access Systems,” 2005.

  However, in the conventional base station, radio resources are secured for packets from each user in the partial usage of subchannel zone of the uplink subframe of the OFDMA system in conformity with the above-mentioned IEEE 802.16 standard. There are problems as shown in

  FIG. 11 shows the relationship between the arrangement of uplink bursts and the data after rearrangement according to the uplink palm base among a plurality of cells. In FIG. 11, the base station BS0 and the base station BS1 use the same frequency, but the uplink palm base uses 0 for the base station BS0 and 27 for the base station BS1. The rearrangement of data from the logical subchannel to the frequency at the time of actual transmission is performed in units called tiles in the logical subchannel. One logical subchannel is composed of six tiles in the frequency direction. As shown in FIG. 11, in both base stations BS0 and BS1, uplink burst # 1 secures logical subchannels in order from the logical subchannel next to the ranging subchannel in the direction in which the logical subchannel number increases. The terminal stations under the base station BS0 have patterns according to the uplink palm base value 0, and the terminal stations under the base station BS1 have patterns according to the uplink palm base value 27. Are arranged on the frequency at the time of actual transmission. Due to this conversion, some of the tiles may be arranged on the same frequency, and thus inter-cell interference occurs between the base station BS0 and the base station BS1.

  In order to prevent this inter-cell interference, it is necessary to rearrange tiles so that terminal stations under different base stations do not use the same frequency. Therefore, in the base station, when the total amount of traffic is sufficiently smaller than the total amount of radio resources, that is, when there is a surplus in uplink resources, as shown in FIG. 12 (a), for pseudo communication for avoiding interference It is conceivable that resources are provided, however, rearrangement is not performed with different uplink palm base values for each base station, and radio resources are not allocated to the same logical subchannel with interfering stations. However, as shown in FIG. 12B, when there is no room for uplink resources, the size of the pseudo communication resource is reduced, and the resource allocated next to the pseudo communication resource is allocated by the interfering station. It may be arranged in the same logical subchannel as the resource, and as a result, the same frequency as that of the interfering station is used, causing interference.

  The present invention has been made in view of such circumstances, and its purpose is to prevent inter-cell interference in the OFDMA uplink partial usage of subchannel zone while complying with the IEEE 802.16 standard and the like. It is an object of the present invention to provide a radio frame control device, a radio frame control method, and a radio communication device capable of configuring a radio frame that can reduce the influence.

  In order to solve the above problems, a radio frame control device according to the present invention is a radio frame control device that controls an uplink radio frame of an orthogonal frequency division multiple access scheme. Communication data amount monitoring means for monitoring the communication data amount acquiring means for acquiring the uplink communication data amount of the base stations in the vicinity of the base station, the uplink communication data amount of the base station and the uplink of the peripheral base station When the total amount of link communication data is less than the reference value, in the uplink radio frame, radio resources for actual communication are secured so as to avoid interference with other stations, and the radio resources that have not been secured are simulated. And radio resource allocating means for allocating for use.

  The radio frame control apparatus according to the present invention comprises terminal station information monitoring means for acquiring information related to interference given to a neighboring base station by a terminal station under its own base station, and the radio resource allocating means is provided to the neighboring base station. A radio resource used by the neighboring base station is allocated to a terminal station whose interference is weaker than a reference.

  In the radio frame control apparatus according to the present invention, the radio resource allocation means allocates a radio resource immediately after the pseudo communication resource to a terminal station closest to the base station.

  In the radio frame control apparatus according to the present invention, the radio resource allocating means allocates a radio resource immediately after the pseudo communication resource to a terminal station whose arrival direction of radio waves is completely different from a direction of a neighboring base station. Features.

  In the radio frame control apparatus according to the present invention, the radio resource allocation means allocates a radio resource immediately after the pseudo communication resource to a terminal station having the best radio propagation environment.

  An orthogonal frequency division multiple access wireless communication apparatus according to the present invention includes any one of the above-described wireless frame control apparatuses.

Radio frame control method according to the present invention, in the radio frame control method for controlling uplink radio frame in an orthogonal frequency division multiple access scheme, the communication data amount monitoring step of monitoring the communication data amount of the uplink of the base station The communication data amount acquisition step for acquiring the uplink communication data amount of the base stations around the base station, and the sum of the uplink communication data amount of the base station and the uplink communication data amount of the peripheral base stations is a reference value A radio resource allocation step for securing radio resources for actual communication so as to avoid interference with other stations in an uplink radio frame, and for allocating radio resources that have not been reserved for pseudo communication in an uplink radio frame; It is characterized by including.

  In the radio frame control method according to the present invention, the radio frame control method further includes a terminal station information monitoring step of acquiring information related to interference given by the terminal station under its own base station to the neighboring base station, wherein in the radio resource allocation step, the neighboring base station A radio resource used by the neighboring base station is allocated to a terminal station whose interference with the base station is weaker than a reference.

  The radio frame control method according to the present invention is characterized in that, in the radio resource assignment step, a radio resource immediately after the pseudo communication resource is assigned to a terminal station closest to the base station.

  In the radio frame control method according to the present invention, in the radio resource allocation step, a radio resource immediately after the pseudo communication resource is allocated to a terminal station in which the arrival direction of the radio wave is completely different from the direction of the neighboring base station. Features.

  The radio frame control method according to the present invention is characterized in that, in the radio resource assignment step, a radio resource immediately after the pseudo communication resource is assigned to a terminal station having the best radio propagation environment.

  According to the present invention, it is possible to configure a radio frame capable of reducing the influence of inter-cell interference while complying with the IEEE 802.16 standard or the like in an OFDMA uplink partial usage of subchannel zone. The effect of becoming.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a radio frame control apparatus according to an embodiment of the present invention. FIG. 2 is a system configuration example for explaining the radio communication system according to the embodiment. The wireless communication system according to the present embodiment is compliant with the IEEE 802.16 standard or the like.

  FIG. 2 illustrates base stations BS0 and BS1 and terminal stations SS0 to SS6 in the wireless communication system. Base stations BS0 and BS1 provide communicable ranges (cells) 100 and 101, respectively. The terminal stations SS0 to SS6 are all in the cell 100 of the base station BS0, wirelessly connected to the base station BS0, and are under the base station BS0. Since the terminal stations SS2, SS4, SS5 and SS6 are also located in the cell 101 of the base station BS1, they can be interference sources of the base station BS1.

  The base stations BS0 and BS1 include the radio frame control apparatus according to the present embodiment shown in FIG. 1, and control the uplink subframes of the OFDMA scheme compliant with the IEEE 802.16 standard or the like. This uplink subframe is illustrated in FIG. Hereinafter, the radio frame controller according to the present embodiment will be described in detail.

  In FIG. 1, the radio frame control apparatus according to the present embodiment includes a radio resource allocation unit 10, an arrangement information generation unit 20, and a pseudo arrangement information generation unit 30. The radio resource allocation unit 10 includes a radio resource allocation processing unit 11, a communication data amount monitoring unit 12, a terminal station information monitoring unit 13, an interference base station use subchannel information database 14, a use subchannel determination unit 15, A rearranging execution unit 16.

  The radio resource allocation processing unit 11 receives radio resource request information transmitted from a terminal station under its own base station. The radio resource request information is a message requesting a resource used by the terminal station for communication (uplink communication) toward the base station. The radio resource allocation processing unit 11 outputs an arrangement information creation request message on the radio frame to the arrangement information generation unit 20 and the pseudo arrangement information generation unit 30 based on the radio resource request information.

  The arrangement information generation unit 20 generates arrangement information based on the arrangement information creation request message received from the radio resource allocation processing unit 11. FIG. 3 is a configuration example of the arrangement information. FIG. 3 also shows the relationship between the arrangement information and the radio frame configuration. The arrangement information is represented in a table format, and attributes include a communication identifier, PHY_MODE, and a resource amount. One line shows information of one terminal station. The unit of the resource amount is a slot. The location on the radio frame to be allocated with the communication identifier, PHY_MODE, and radio resource amount of each terminal station is instructed from the radio resource allocation processing unit 11 by the creation request message. The arrangement information generation unit 20 transmits the generated arrangement information to the radio resource allocation processing unit 11. The arrangement information (FIG. 3) generated by the arrangement information generation unit 20 is the same as the conventional arrangement information shown in FIG.

  The pseudo arrangement information generation unit 30 generates arrangement information based on the arrangement information creation request message received from the radio resource allocation processing unit 11. FIG. 4 is a configuration example of the arrangement information. FIG. 4 also shows the relationship between the arrangement information and the radio frame configuration. The arrangement information generated by the pseudo arrangement information generation unit 30 is the same as the arrangement information generated by the arrangement information generation unit 20 and is represented in a table format. Attributes include a communication identifier, PHY_MODE, and a resource amount. However, the communication identifier includes a pseudo communication identifier representing virtual wireless communication (referred to as pseudo communication). In the arrangement information in FIG. 4, “99” is shown as an example of the pseudo communication identifier.

  The pseudo communication identifier is assigned to virtual wireless communication. Therefore, the PHY_MODE and the resource amount allocated to the pseudo communication identifier are not actually used. The number of pseudo communications, the amount of provisional radio resources allocated to each pseudo communication, and the location on the radio frame to be allocated are instructed from the radio resource allocation processing unit 11 by the creation request message. In the example of FIG. 4, the information of one pseudo communication resource is further added to the arrangement information of FIG. 3. In the arrangement information of FIG. 4, 8 slots are reserved in the uplink burst # 4 from the first slot of the 13th logical subchannel to the last slot of the 14th logical subchannel as pseudo communication resources. The pseudo arrangement information generation unit 30 transmits the generated arrangement information to the radio resource allocation processing unit 11.

  The communication data amount monitoring unit 12 monitors the amount of uplink communication data received by the base station, and outputs a statistical value of the data amount to the use subchannel determination unit 15.

  The terminal station information monitoring unit 13 receives the position information of the terminal station (position information in the cell) from the backbone network. In the backbone network, the position information of the terminal station is obtained using GPS (Global Positioning System) or the like. In addition, the terminal station information monitoring unit 13 receives information on the radio wave arrival direction and received signal strength (Received Signal Strength Indicator: RSSI) from the terminal station from the receiving unit of the base station. Based on the received information, the terminal station information monitoring unit 13 relates to terminal stations under its own base station, and information on terminal stations that can be interference sources for base stations (interfering base stations) around the base station. (Interfering terminal station information) is created. The terminal station information monitoring unit 13 outputs the interfering terminal station information to the use subchannel determination unit 15.

  FIG. 5 is a configuration example of the interfering terminal station information. In the example of FIG. 5, the terminal stations SS1 to SS6 under its own base station BS0 can be interference sources with respect to the interfering base stations BS1, BS2, and BS3. The terminal station information monitoring unit 13 determines the strength of interference given by the terminal station for each of the interference base stations BS1, BS2, and BS3, and includes the determination result in the interfering terminal station information. The interfering terminal station information in FIG. 5 indicates that, for example, the interference given to the interfering base station BS1 becomes stronger in the order of the terminal stations SS1, SS3, SS5, SS6, SS4, SS2.

  The terminal station information monitoring unit 13 classifies the terminal stations according to the degree of interference. The terminal station information monitoring unit 13 is preliminarily provided with a threshold value that delimits the strength of interference as the degree of interference strength. The terminal station information monitoring unit 13 obtains the degree of interference of each terminal station, compares it with the threshold value, and classifies the terminal stations based on the threshold value. In the interfering terminal station information of FIG. 5, for example, with respect to the interfering base station BS1, the terminal stations SS1 and SS3 are weak interference sources whose degree of interference is less than a threshold, and the terminal stations SS5, SS6, SS4, SS2 Is a strong interference source having a degree of interference greater than or equal to a threshold value. For the interfering base station BS3, all the terminal stations SS1 to SS6 are strong interference sources whose degree of interference is not less than a threshold value. A weak interference source having a degree of interference less than a threshold value has little influence on the interference base station in terms of communication quality.

  As an index for the terminal station information monitoring unit 13 to determine the degree of interference intensity of the terminal station, for example, the distance between the base station and the terminal station, the radio wave from the terminal station to the base station, An arrival direction, a radio propagation environment value (for example, RSSI) between the own base station and the terminal station can be used.

  The interference base station use subchannel information database 14 stores use subchannel information notified from the interference base station. Used subchannel information is exchanged between neighboring base stations. The base station notifies the interfering base station of the number of the logical subchannel used by the own station and the statistical value of the uplink communication data amount of the own station based on the used subchannel information. The interference base station use subchannel information database 14 updates the stored contents with the use subchannel information received from the interference base station. Thereby, the interference base station use subchannel information database 14 stores the latest use subchannel information of the interference base station (the number of the logical subchannel used by the interference base station, the statistics of the uplink communication data amount of the interference base station). Value) is stored.

  The used subchannel determination unit 15 generates terminal station usable subchannel information. The terminal station usable subchannel information indicates logical subchannels that can be used by terminal stations under its own base station. FIG. 6 is a configuration example of the terminal station usable subchannel information. The terminal station usable subchannel information indicates which terminal station can use which logical subchannel. In the example of FIG. 6, the number of a terminal station that can use the logical subchannel is shown in association with the logical subchannel number. In addition, a logical subchannel that cannot be used by any terminal station has no usable terminal station. The column of logical subchannels without usable terminal stations is left blank.

Here, a method in which the used subchannel determining unit 15 determines a logical subchannel that can be used by a terminal station under its own base station will be described.
The used subchannel determination unit 15 receives the statistical value of the uplink communication data amount of the local station from the communication data amount monitoring unit 12. Also, the used subchannel determination unit 15 receives the interfering terminal station information from the terminal station information monitoring unit 13. Also, the used subchannel determination unit 15 reads the latest used subchannel information of the interference base station from the interference base station used subchannel information database 14. The used subchannel information includes the number of the logical subchannel used by the interfering base station and the statistical value of the uplink communication data amount of the interfering base station.

  The used subchannel determination unit 15 changes a method for determining a logical subchannel that can be used by a terminal station under its own base station according to the amount of uplink traffic. Hereinafter, the determination method will be described separately for the case where the uplink traffic volume exceeds the reference value and the case where the uplink traffic volume is less than the reference value.

[When the amount of uplink traffic exceeds the standard value]
The used subchannel determination unit 15 adds up the statistical value of the uplink communication data amount of the own station and the statistical value of the uplink communication data amount of the interfering base station, and when the total value is larger than the reference value, In the terminal station usable subchannel information, all logical subchannel fields are blank. In this case, the logical subchannel that can be used by the terminal stations under its own base station is not specified.

[When the uplink traffic volume is below the reference value]
When the total value of the statistical value of the uplink communication data amount of the own station and the statistical value of the uplink communication data amount of the interference base station is equal to or less than the reference value, the used subchannel determination unit 15 Based on the station information and the logical subchannel used by the interfering base station, the logical subchannel that can be used by the terminal station under the base station is determined. Here, as a specific example, description will be given using the interfering terminal station information of FIG. 5 and the logical subchannel used by the interfering base station shown in FIG. In the example of FIG. 7, the interfering base station BS1 uses the second logical subchannel, the third logical subchannel, and the eleventh logical subchannel, and the interfering base station BS2 uses the sixth logical subchannel and the seventh logical subchannel. The interfering base station BS3 uses the 8th logical subchannel and the 9th logical subchannel. The fourth, fifth, tenth, twelfth and thirteenth logical subchannels are empty. The first logical subchannel is assigned to the ranging subchannel according to the IEEE 802.16 standard or the like. Accordingly, in the terminal station usable subchannel information, the first logical subchannel is not used and the first logical subchannel column is blank.

  First, the used subchannel determination unit 15 extracts a terminal station that is a weak interference source having a degree of interference less than a threshold with respect to the interfering base station in the interfering terminal station information. In the interfering terminal station information of FIG. 5, terminal stations SS1 and SS3 are extracted for the interfering base station BS1, and terminal stations SS2 and SS5 are extracted for the interfering base station BS2. No one is extracted for the interfering base station BS3.

  Next, the used subchannel determination unit 15 assumes that, in the extracted combination of the interference base station and the terminal station, the used logical subchannel of the interference base station can be used by the terminal station of the combination. This is because a terminal station, which is a weak interference source whose degree of interference is less than the threshold, has little influence on the interference base station in terms of communication quality. Thereby, as shown in FIG. 6, the terminal stations SS1 and SS3 can use the logical subchannels (No. 2, No. 3, and No. 11) of the interference base station BS1. Further, the use logical subchannels (Nos. 6 and 7) of the interference base station BS2 can be used by the terminal stations SS2 and SS5.

  Next, the used subchannel determining unit 15 has no usable terminal station for the used logical subchannel of the interfering base station from which no terminal station that is a weak interference source whose degree of interference is less than the threshold is extracted. And As a result, as shown in FIG. 6, the logical subchannels (Nos. 8 and 9) of the interfering base station BS3 have no usable terminal stations. The columns of the eighth and ninth logical subchannels are left blank.

  Next, the use subchannel determination unit 15 assumes that all terminal stations can use a logical subchannel (free subchannel) that is not used by any interference base station. As a result, as shown in FIG. 6, all the terminal stations SS1 to SS6 can be used for the empty subchannels (Nos. 4, 5, 10, 12, and 13).

  The above is the description of the method for determining the usable logical subchannels of the terminal stations under its own base station.

  The used subchannel determination unit 15 outputs the terminal station usable subchannel information to the radio resource allocation processing unit 11 and the rearrangement performing unit 16.

  The radio resource allocation processing unit 11 determines radio resources to be allocated to a terminal station that has requested a radio resource, based on terminal station usable subchannel information. The radio resource allocation processing unit 11 changes the radio resource allocation method depending on whether or not all logical subchannel fields are blank in the terminal station usable subchannel information. Hereinafter, the allocation method will be described separately for the case where all logical subchannel columns are blank and the case where all logical subchannel columns are not blank in the terminal station usable subchannel information.

[When all the logical subchannel fields are blank in the terminal station usable subchannel information]
When all the logical subchannel fields are blank in the terminal station usable subchannel information, the amount of uplink traffic is large, and it is difficult to secure the resources for pseudo communication. The interference base station uses all the logical subchannels, and no terminal station that is a weak interference source whose degree of interference is less than the threshold is extracted in all the logical subchannels used. Even in this case, all the logical subchannel fields are blank in the terminal station usable subchannel information.
The radio resource allocation processing unit 11 allocates radio resources in order from the first logical subchannel (except that the first logical subchannel is dedicated to the ranging subchannel). At this time, the radio resources are allocated so as not to be vacant. The radio resource allocation processing unit 11 includes the radio resource allocation result in the arrangement information creation request message, and sends the creation request message to the arrangement information generation unit 20. In the creation request message, a communication identifier, PHY_MODE, and a radio resource amount and a location on a radio frame to be assigned are indicated for a terminal station to which radio resources are assigned. In this case, the pseudo arrangement information generating unit 30 is not sent an arrangement information creation request message. Therefore, the pseudo arrangement information generation unit 30 does not generate arrangement information.

[When all logical subchannel fields are not blank in the terminal station usable subchannel information]
When all the logical subchannel fields are not blank in the terminal station usable subchannel information, the amount of uplink traffic is small and pseudo communication resources can be secured.
In the terminal station usable subchannel information, the radio resource allocation processing unit 11 allocates radio resources from logical subchannels that can be used by the terminal station to be allocated. Further, among the logical subchannels that can be used by the terminal station to be allocated, allocation is performed preferentially from empty subchannels that are not used by any interfering base station. This is because no interference occurs in an empty subchannel that is not used by any interfering base station. In the terminal station usable subchannel information, logical subchannels that can be used by all terminal stations are treated as empty subchannels that are not used by any interference base station.

  Further, the radio resource allocation processing unit 11 allocates pseudo communication resources. A logical subchannel that is not assigned to a terminal station and has a smaller number than the maximum number of logical subchannels assigned to the terminal station is assigned to the pseudo communication resource.

In addition, as a method of determining the allocation location of a radio | wireless resource, the following methods 1-3 are mentioned, for example.
(Method 1) In the case of a terminal station that is the closest to the own base station, it is considered that there is a low possibility that a communication error occurs in communication with the own base station. Thereby, the resource immediately after the pseudo communication resource is allocated to the terminal station closest to the base station.
(Method 2) When the arrival direction of the radio wave from the terminal station is different from the direction of the interfering base station, it is considered that there is a low possibility that a communication error occurs in communication with the own base station. As a result, a resource immediately after the pseudo communication resource is allocated to a terminal station whose arrival direction of radio waves is completely different from the direction of the interference base station.
(Method 3) In the case of a terminal station having the best radio propagation environment between the base station and the terminal station, it is considered that the possibility of communication errors occurring in communication with the base station is low. As a result, the resource immediately after the pseudo communication resource is allocated to the terminal station with the best wireless propagation environment.

  The radio resource allocation processing unit 11 includes the radio resource allocation result in an arrangement information creation request message, and sends the creation request message to the pseudo arrangement information generation unit 30. In the creation request message, a communication identifier, PHY_MODE, and a radio resource amount and a location on a radio frame to be assigned are indicated for a terminal station to which radio resources are assigned. Further, the creation request message indicates the number of pseudo communications, the provisional radio resource amount to be allocated to each pseudo communication, and the location on the radio frame to be allocated for the pseudo communication resource. In this case, no arrangement information creation request message is sent to the arrangement information generation unit 20. Therefore, the arrangement information generation unit 20 does not generate arrangement information.

  The above is the description of the radio resource allocation method.

  When all the logical subchannel fields are blank in the terminal station usable subchannel information, the radio resource allocation processing unit 11 receives the arrangement information from the arrangement information generation unit 20 and rearranges the arrangement information. 16 is output. The reordering unit 16 operates only when all the logical subchannel fields are blank in the terminal station usable subchannel information.

  The rearrangement execution unit 16 designates the rearrangement pattern in the frequency direction by the uplink palm base value unique to the own base station, and sends the arrangement information to the terminal station. As a result, the terminal station converts the data arranged in the logical subchannel indicated in the arrangement information into a sequence according to the designated uplink palm base value on the actual frequency, and then uplinks the data. Send. Also, the rearrangement execution unit 16 sends the logical subchannel number used by the base station and the statistical value of the uplink communication data amount of the base station to the interference base station.

  On the other hand, when all the logical subchannel fields are not blank in the terminal station usable subchannel information, the radio resource allocation processing unit 11 receives the arrangement information from the pseudo arrangement information generating unit 30. In this case, the radio resource allocation processing unit 11 designates a rearrangement pattern in the frequency direction by a unique uplink palm base value common to all base stations, and sends arrangement information to the terminal station. As a result, the terminal station converts the data arranged in the logical subchannel indicated in the arrangement information into a sequence according to the designated uplink palm base value on the actual frequency, and then uplinks the data. Send. In addition, the radio resource allocation processing unit 11 sends the number of the logical subchannel used in the own base station and the statistical value of the uplink communication data amount of the own base station to the interference base station.

FIG. 8 is a flowchart showing a procedure of radio frame control processing performed by the radio frame controller according to the present embodiment.
In FIG. 8, in step S1, as the initial setting, the frequency direction is not rearranged by the pattern according to the uplink palm base value unique to the own base station, and the only uplink palm base common to all base stations is used. It is assumed that the frequency direction is rearranged by the pattern according to the value.

  In step S2, the statistical value of the uplink communication data amount of the own station and the statistical value of the uplink communication data amount of the interfering base station are summed, and it is determined whether or not the total value is larger than a threshold value. As a result, when the total value is larger than the threshold value, the process proceeds to step S3, and when the total value is equal to or less than the threshold value, the process proceeds to step S6.

  In step S3, information in a table format in which all logical subchannel fields are blank is generated as terminal station usable subchannel information. In step S4, radio resources are allocated in order from the first logical subchannel (except that the first logical subchannel is dedicated to the ranging subchannel). At this time, the radio resources are allocated so as not to be vacant. In step S5, uplink transmission is controlled so that the frequency direction is rearranged according to the pattern according to the uplink palm base value specific to the base station.

  In step S6, information (interfering terminal station information) of terminal stations under its own base station that can be an interference source for the interfering base station is generated. In step S7, based on the interfering terminal station information and the logical subchannel used by the interfering base station, information on usable logical subchannels (terminal station usable subchannel information) of the terminal stations under its own base station is generated. To do.

In step S8, based on the terminal station usable subchannel information, assignment destination terminal stations are determined in order from logical subchannels with many usable terminal stations (that is, logical subchannels with less influence of interference). At this time, logical subchannels that can be used by all terminal stations in the terminal station usable subchannel information are treated as empty subchannels that are not used by any interference base station. Then, the logical subchannels determined to be free subchannels are preferentially assigned.
In step S9, a logical subchannel that is not allocated to the terminal station and that has a smaller number than the maximum number of logical subchannels allocated to the terminal station is allocated to the resource for pseudo communication.

  According to the above-described embodiment, in the uplink partial usage of subchannel zone of the OFDMA scheme, a radio frame that can reduce the influence of inter-cell interference while conforming to the IEEE 802.16 standard or the like is configured. Can be obtained.

  Furthermore, since a logical subchannel used by the interfering base station may be allocated to a terminal station with less interference with respect to the interfering base station, the influence of inter-cell interference is reduced and frequency utilization is reduced. Efficiency can be improved.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

It is a block diagram which shows the structure of the radio | wireless frame control apparatus which concerns on one Embodiment of this invention. It is a system configuration example for demonstrating the radio | wireless communications system which concerns on the embodiment. It is an example of composition of arrangement information concerning the embodiment. It is an example of composition of arrangement information concerning the embodiment. It is an example of a structure of the interference terminal station information which concerns on the same embodiment. 4 is a configuration example of terminal station usable subchannel information according to the embodiment. It is an example of the use subchannel of an interference base station. It is a flowchart which shows the procedure of the radio | wireless frame control process which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the uplink sub-frame of an OFDMA system. It is a figure which shows the relationship between the conventional arrangement | positioning information and an uplink sub-frame structure. It is a figure explaining the conventional uplink sub-frame. It is a figure explaining the conventional uplink sub-frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Radio | wireless resource allocation part, 11 ... Radio | wireless resource allocation process part, 12 ... Communication data amount monitoring part, 13 ... Terminal station information monitoring part, 14 ... Interference base station use subchannel information database, 15 ... Use subchannel determination part, 16 ... rearrangement execution unit, 20 ... arrangement information generation unit, 30 ... pseudo arrangement information generation unit

Claims (11)

In a radio frame controller for controlling an uplink radio frame of an orthogonal frequency division multiple access scheme,
A communication data amount monitoring means for monitoring the uplink communication data amount of the base station;
Communication data amount acquisition means for acquiring the uplink communication data amount of base stations in the vicinity of the base station;
When the sum of the uplink communication data volume of the own base station and the uplink communication data volume of the neighboring base stations is less than the reference value, in the uplink radio frame, for actual communication, avoid interference with other stations. Radio resource allocating means for securing radio resources and allocating radio resources not secured for pseudo communication;
A radio frame control device comprising: Comprising terminal station information monitoring means for acquiring information related to interference given to a base station by a terminal station under its own base station;
The radio frame according to claim 1, wherein the radio resource allocating unit allocates a radio resource used by the neighboring base station to a terminal station whose interference to the neighboring base station is weaker than a reference. Control device.   The radio frame control apparatus according to claim 2, wherein the radio resource allocating unit allocates a radio resource immediately after the pseudo communication resource to a terminal station closest to the base station.   3. The radio frame according to claim 2, wherein the radio resource allocating unit allocates a radio resource immediately after the pseudo communication resource to a terminal station whose arrival direction of radio waves is completely different from a direction of a neighboring base station. Control device.   3. The radio frame control apparatus according to claim 2, wherein the radio resource allocation unit allocates a radio resource immediately after the pseudo communication resource to a terminal station having the best radio propagation environment.   An orthogonal frequency division multiple access wireless communication apparatus comprising the wireless frame control apparatus according to any one of claims 1 to 5. In a radio frame control method for controlling an uplink radio frame of an orthogonal frequency division multiple access scheme,
A communication data amount monitoring step for monitoring the uplink communication data amount of the base station;
A communication data amount acquisition step for acquiring the uplink communication data amount of base stations around the base station;
When the sum of the uplink communication data volume of the own base station and the uplink communication data volume of the neighboring base stations is less than the reference value, in the uplink radio frame, for actual communication, avoid interference with other stations. A radio resource assignment step for securing radio resources and allocating radio resources not secured for pseudo communication;
A radio frame control method comprising: It further includes a terminal station information monitoring step of acquiring information related to interference given to a neighboring base station by a terminal station under its base station,
8. The radio frame according to claim 7, wherein, in the radio resource allocation step, a radio resource used by the neighboring base station is assigned to a terminal station whose interference given to the neighboring base station is weaker than a reference. Control method.   9. The radio frame control method according to claim 8, wherein in the radio resource allocation step, a radio resource immediately after the pseudo communication resource is allocated to a terminal station that is closest to the base station.   9. The radio frame according to claim 8, wherein, in the radio resource assignment step, a radio resource immediately after the pseudo communication resource is assigned to a terminal station in which a radio wave arrival direction is completely different from a direction of a neighboring base station. Control method.   9. The radio frame control method according to claim 8, wherein, in the radio resource assignment step, a radio resource immediately after the pseudo communication resource is assigned to a terminal station having the best radio propagation environment.

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