JP2011229089A - Terminal device, base station and wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal device, a base station and a wireless communication system capable of more effective band allocation.SOLUTION: A base station 11 includes a band allocation request receiving unit 1141 which receives a band allocation request and a band allocation control unit 1142 which executes the allocation of wireless resources based on the band allocation request. The band allocation control unit 1142 refers to a sending reserve capacity sent from a terminal device 12 by using a channel used for the band allocation request and to a response bit which represents the possibility of the increase of the number of the wireless resources toward a frequency direction by binary. When the response bit is set to the value which indicates the increase of the number of wireless resources toward the frequency direction is possible, the band allocation control unit 1142 increases the allocation of the already-allocated wireless resources toward the frequency direction and decreases the allocation of the already-allocated wireless resources toward a time direction.

Description

  The present invention relates to a terminal device, a base station, and a wireless communication system that perform communication using an OFDMA (Orthogonal Frequency Division Multiple Access) method.

  In a next-generation PHS (Personal Handyphone System) wireless communication system, centralized power control by a terminal device is possible, and the terminal device is configured to request radio resource allocation (bandwidth allocation) from a base station. .

  FIG. 15 shows an example of the configuration of an ECCH (Extra Channel Control Channel) physical header described in Non-Patent Document 1, and FIG. 15 (a) shows an ANCH (Anchor Channel) physical in OFDMA. FIG. 15B shows an ANCH physical header in SC (Single Carrier), and communication using the OFDMA system uses the physical header shown in FIG. 15A. For communication using a single carrier, the physical header shown in part (b) of FIG. 15 is used.

  As shown in FIG. 15, the first 7 bits of the physical header are set as RCH (Request Channel) for requesting bandwidth allocation, and the base station is requested to allocate radio resources using this RCH.

  In the base station that has received the bandwidth allocation request, radio resources are allocated based on the requested bandwidth information included in the RCH. However, since the allocation requests are made from a plurality of terminal devices, a finite radio resource is allocated to the base station. Efficient distribution is required.

  However, as shown in Chapter 4.3.6.9 of Non-Patent Document 1, the bandwidth allocation request includes only information on the requested bandwidth, and if allocation is performed based on such information, efficient bandwidth allocation is possible. It included possibilities that could not be done.

“ARIB STD-T95“ OFDMA / TDMA TDD Broadband Wireless Access System (Next Generation PHS) ARIB STANDARD ”Version 1.3”, December 6, 2009, Japan Radio Industry Association

  As described above, in the related art, since the base station performs bandwidth allocation based on a bandwidth allocation request that includes only requested bandwidth information, there is a problem that efficient bandwidth allocation cannot be performed.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a terminal device, a base station, and a wireless communication system that enable more efficient band allocation.

  A base station according to the present invention is a base station that performs radio communication with a terminal device, and a bandwidth allocation request for requesting radio resource allocation from the terminal device to the base station is made, and the base station A bandwidth allocation request accepting unit that accepts a bandwidth allocation request; and a bandwidth allocation control unit that executes radio resource allocation based on the bandwidth allocation request, wherein the bandwidth allocation control unit is a channel used for the bandwidth allocation request. Is determined to be able to increase the number of radio resources in the frequency direction by receiving information on whether or not it is possible to increase the transmission capacity and the number of radio resources transmitted from the terminal device using In this case, change the allocation of already allocated radio resources so that it increases in the frequency direction and decreases in the time direction, or will be allocated in the future. That the allocation of radio resources by increasing the number of frequency direction is set so as to reduce the number of the time direction.

  A terminal apparatus according to the present invention is a terminal apparatus that performs radio communication with a base station, wherein the terminal apparatus generates a band allocation request for requesting radio resource allocation to the base station. The bandwidth allocation request creating unit creates information on whether transmission capacity and the number of radio resources can be increased in the frequency direction, and uses a channel used for the bandwidth allocation request. To the base station.

  A radio communication system according to the present invention includes a terminal device and a base station, and a bandwidth allocation request for requesting radio resource allocation from the terminal device to the base station is made, and the base station A bandwidth allocation request accepting unit that accepts a request; and a bandwidth allocation control unit that executes radio resource allocation based on the bandwidth allocation request, wherein the bandwidth allocation control unit uses a channel used for the bandwidth allocation request Then, referring to information on whether or not it is possible to increase the transmission capacity and the number of radio resources transmitted from the terminal apparatus in the frequency direction, the number of radio resources can be increased in the frequency direction from the information. If it is determined to be possible, change the allocation of the already allocated radio resources to increase in the frequency direction and decrease in the time direction, or The allocation of radio resources to be allocated is set so that the number in the frequency direction is increased and the number in the time direction is decreased, and the terminal apparatus creates a bandwidth allocation request for requesting the base station to allocate radio resources. A bandwidth allocation request creation unit that creates information about whether or not the transmission capacity and the number of radio resources can be increased in the frequency direction, and uses the bandwidth allocation request for the bandwidth allocation request. Transmitted to the base station using a channel to be transmitted.

  The base station according to the present invention enables more efficient band allocation.

  The terminal device according to the present invention enables more efficient band allocation.

  According to the communication system according to the present invention, more efficient band allocation is possible.

It is a figure which shows the frame structure of a next-generation PHS system. It is a figure explaining an example of the setting of a response bit. It is a flowchart which shows the 1st example of the radio | wireless resource allocation operation | movement in a base station. It is a figure which shows typically the area | region which cannot be allocated to a specific terminal device. It is a figure which shows typically the area | region which cannot be allocated to a specific terminal device. It is a figure which shows an example of radio | wireless resource allocation typically. It is a figure which shows typically an example of the allocation operation | movement which optimizes radio | wireless resource allocation. It is a flowchart which shows the 2nd example of the radio | wireless resource allocation operation | movement in a base station. It is a figure which shows typically an example of the allocation operation | movement which optimizes radio | wireless resource allocation. It is a flowchart which shows the 3rd example of the radio | wireless resource allocation operation | movement in a base station. It is a figure which shows typically an example of the allocation operation | movement which optimizes radio | wireless resource allocation. It is a figure which shows the structure of the radio | wireless communications system which concerns on this invention. It is a block diagram which shows the structure of the base station which concerns on this invention. It is a block diagram which shows the structure of the terminal device which concerns on this invention. It is a figure which shows the structure of the physical header of ECCH.

<Embodiment>
<Notification of transmission capacity>
As described above, conventionally, the base station performs bandwidth allocation based on information on the requested bandwidth from the terminal device, but the terminal device only requests bandwidth allocation. If it is not possible to know how much the transmission capability is, and if it is not possible to transmit by allocating a bandwidth as requested, wireless resources are wasted.

  Therefore, regardless of whether or not the terminal device has centralized power control, it is conceivable as an effective method to store information on transmission capacity in the RCH of the physical header of the ECCH as information for determining the transmission capability. Here, the transmission capacity is a value obtained by subtracting power (transmission power) required for transmission of control radio resources from the maximum transmission output of the terminal device.

  The information on the transmission capacity is notified using the lower 5 bits in the 7-bit RCH, and can be expressed as, for example, 32 power values from 0 dB to 31 dB.

  Further, the upper 2 bits of the RCH are used as an identifier. For example, if it is “01”, it can be notified to the base station that it is information of transmission capacity. When the upper 2 bits are set to “00”, the uplink (UL) data amount can be notified using the lower 5 bits.

  The base station that has received the information on the transmission capacity can determine the number of radio resources for data to be allocated in the frequency direction with reference to the transmission capacity.

  However, as described above, the remaining transmission power considers the transmission power of the radio resource for control in calculating the value, but does not consider the transmission power of the radio resource for data. For this reason, the base station cannot determine whether or not the number of allocated radio resources for data is an optimal value, and as a result, there are cases where the allocated number of radio resources to the terminal device cannot be optimized. In view of this, the inventor made the following invention in order to make the information on the transmission capacity more effective.

<Next-generation PHS frame configuration>
First, the frame configuration of the next generation PHS will be described. In the next-generation PHS wireless communication system, as in the current PHS, in the period of 5 msec per frame, the uplink (UL) and the downlink (DL) are each time-divided by 2.5 msec, and the UL and DL Are time-divided into four time slots (hereinafter referred to as “slots”).

  Here, FIG. 1 shows a frame configuration when each slot is composed of 9 subchannels.

  That is, as shown in FIG. 1, the uplink (UL) is time-divided into four slots 1 to 4, and the downlink (DL) is time-divided into four slots 5 to 8. The slot is composed of nine subchannels of subchannels 1 to 9. Here, one subchannel in one slot is called a PRU (Physical Resource Unit), and this one PRU becomes one radio resource.

  As shown in FIG. 1, in the uplink, subchannel 1 in slot 1 is referred to as PRU1, subchannel 1 in slot 2 is referred to as PRU2, and thereafter the unit number is incremented by one. And subchannel 2 is assigned from PRU5 to PRU8. Hereinafter, unit numbers are assigned to slots 1 to 4 according to the same rule, and an uplink frame is composed of 36 PRUs from PRU1 to PRU36. A unit number is assigned to the downlink in the same manner, but is not shown.

  In the following description, for the sake of convenience, description will be made on the assumption that each of the four uplink slots is composed of four subchannels of subchannel 1 to subchannel 4.

<Notification of response bit>
In the terminal apparatus according to the present invention, an index value called a response bit is determined based on the actual value of the transmission capacity calculated in consideration of the transmission power of the radio resource for data, and is used as the physical header of the ECCH. Set to RCH and transmit. In response to this, the base station optimizes the number of radio resources allocated to the terminal device by changing the arrangement of already allocated data radio resources (PRU) according to the response bit.

  Specifically, the response bit is set based on the actual value of the transmission capacity, which is a value obtained by subtracting the transmission power of the control radio resource and the transmission output of the data radio resource from the maximum transmission output of the terminal device that is the device itself. For example, if the actual value of the transmission capacity is positive, the response bit is set to “0”, and if it is negative, “1” is set.

  Here, FIG. 2 shows an example of response bit setting in the 7-bit RCH. The upper 2 bits of the RCH shown in FIG. 2 are used as an identifier. For example, if “10”, the RCH is used for transmission of response bits, and the 4 slots of the uplink ( A response bit for each of slots 1 to 4) is notified. For example, the slot 1 response bit is set in the least significant first bit, the slot 2 response bit is set in the second bit, the slot 3 response bit is set in the third bit, and the slot 4 is set in the fourth bit. Set the response bit.

<First Example of Optimization of Radio Resource Allocation>
Next, the operation of optimizing the allocation of radio resources at the base station that has received the response bit notification will be described with reference to FIGS.

  FIG. 3 is a flowchart showing PRU allocation operation for transmitting a data channel (EXCH: Extra Channel) in the base station.

  In FIG. 3, when the allocation of EXCH is started, the base station transmits the allocation of EXCH (in order to transmit the EXCH to the terminal device that has transmitted the bandwidth allocation request using the RCH of the physical header of the ECCH in the order in which the request is received. PRU allocation).

  First, it is confirmed whether or not the allocation of EXCH has been completed for all the terminal devices that have transmitted the bandwidth allocation request (step S1). If the allocation has been completed, the allocation of EXCH is terminated. If there is a terminal device that has not been assigned an EXCH, an EXCH is assigned to the terminal device based on the transmission capacity (step S2).

  Then, in step S3, it is confirmed whether or not there is an unallocated radio resource area, that is, an empty area, for the four uplink slots managed by the base station. The EXCH is allocated to the terminal device having the bandwidth allocation request by repeating the above operation. If there is no free area, the process proceeds to step S4 and the response of the terminal device that has allocated the EXCH so far The bit is confirmed, and it is determined whether or not there is a terminal device having a slot in which “0” is set in the response bit (step S4).

  Here, if there is no terminal device having a slot in which “0” is set in the response bit, the EXCH allocation is terminated on the assumption that no more EXCH allocation is possible, but “0” is set in the response bit. If there is a terminal device having the designated slot, the EXCH assignment of the terminal device is reviewed. As a result, after the free space is secured, the operations after step S1 are repeated, and the EXCH is allocated to the terminal device having the bandwidth allocation request.

  The above operation will be schematically described with reference to FIGS. 4 to 7 schematically show the four slots of the uplink as each slot is composed of four subchannels of subchannels 1 to 4. 4 to 7 will be described assuming that there is a bandwidth allocation request from two terminal devices, terminal device A and terminal device B.

  4 schematically shows that among the four slots, the slot 4 is an area that cannot be allocated to the terminal device A, and FIG. 5 shows the slot among the four slots. 1 schematically shows that the area cannot be assigned to the terminal device B.

  As described above, the reason why there is an area that cannot be allocated to a specific terminal device is that there is another terminal device connected to another base station near the terminal device A, and the other terminal device. Is using the same band as slot 4, there is a possibility that if the band of slot 4 is allocated to terminal device A, there is a possibility of interference.

  FIG. 6A shows an example in which there is a bandwidth allocation request from the terminal device A and bandwidth allocation is performed in accordance with the bandwidth allocation request when there is such a restriction.

  Here, the terminal device A requests allocation of data corresponding to nine PRUs, and the base station determines from the transmission capacity that only three PRUs of data can be transmitted in one slot. As shown in part (a) of FIG. 6, band allocation is performed so that the PRUs of the subchannels 1 to 3 are used for each of the slots 1 to 3. At this time, as described above, the allocation of the bandwidth of the slot 4 to the terminal device A is restricted.

  It is assumed that after such band allocation, there is a data allocation request corresponding to 7 PRUs from the terminal apparatus B.

  Although the terminal device B can transmit data for four PRUs in one slot from the transmission capacity, as described above, since the allocation of the bandwidth of the slot 1 is limited, On the other hand, as shown in part (b) of FIG. 6, only six PRUs of the four PRUs of the slot 4 and the PRUs of the subchannels 4 of the slots 2 and 3 can be allocated. B allocation request cannot be satisfied.

  As described above, there is a possibility that an unallocated area that cannot be allocated to any terminal device may occur only with the information on the transmission capacity, and the allocation request cannot be satisfied even though there is an unallocated area. A terminal device will appear, and there is a possibility that efficient bandwidth allocation cannot be performed.

  However, according to the assignment operation according to the flowchart shown in FIG. 3, such a possibility can be reduced.

  FIG. 7 is a diagram schematically showing an allocation operation according to the flowchart shown in FIG. 3. In FIG. 7A, nine PRUs are allocated in accordance with a bandwidth allocation request from the terminal device A. The state is shown (corresponding to the process of step S1 in FIG. 3). In this state, since the terminal apparatus B that requests the allocation of data corresponding to seven PRUs has not been allocated, the allocation is performed based on the transmission capacity by the process shown in step S2 of FIG. As a result, PRUs are allocated as shown in part (b) of FIG. 7. However, it is determined that the request from the terminal device B requesting seven PRUs cannot be satisfied and that there is no free area. (Corresponding to step S3 in FIG. 3).

  On the other hand, the response bit of the terminal device A that has already assigned the EXCH is confirmed, and it is determined whether or not it has a slot in which the response bit is set to “0” (in the process of step S4 in FIG. Equivalent).

  Here, it is assumed that “0” is set in the response bits of the slots 1 and 2 in the response bit of the terminal device A. That is, according to the transmission capacity of the terminal device A, it is determined that only three PRUs of data can be transmitted in one slot, but the response bit set based on the actual value of the transmission capacity is “0”. Therefore, it is determined that data transmission for four PRUs in one slot is possible, and the base station reviews the assignment of EXCH assigned to the terminal device A (corresponding to the process of step S5 in FIG. 3). ).

  As a result, as shown in part (c) of FIG. 7, in slot 1 and slot 2, all four PRUs are assigned to terminal device A, and the PRU of subchannel 1 in slot 3 is assigned to terminal device A. By doing so, the remaining seven PRUs can all be allocated to the terminal apparatus B, and the allocation request of the terminal apparatus B can be satisfied.

  Thus, based on the response bit of the terminal apparatus that has already assigned the PRU, the PRU assignment is optimized by increasing the frequency-direction PRU assignment to the terminal apparatus and reducing the time-direction PRU assignment. Thus, efficient band allocation can be performed.

<Second Example of Optimization of Radio Resource Allocation>
Next, a second example of radio resource allocation optimization at the base station will be described with reference to FIGS.

  FIG. 8 is a flowchart showing PRU allocation operation for transmitting EXCH at the base station.

  In FIG. 8, when the allocation of EXCH is started, the base station transmits the allocation of EXCH (for transmitting the EXCH in the order in which the request is received) to the terminal device that has transmitted the bandwidth allocation request using the RCH of the physical header of the ECCH. PRU allocation).

  First, it is confirmed whether or not the allocation of EXCH is completed for all the terminal devices that have transmitted the bandwidth allocation request (step S11). If the allocation is completed, the allocation of EXCH is terminated. If there is a terminal device that has not been assigned an EXCH, the process proceeds to step S12, where the response bit of the terminal device that requests the assignment is confirmed, and whether or not there is a slot in which “0” is set in the response bit. Determine.

  Here, if there is no slot in which “0” is set in the response bit, the process proceeds to step S14, and the EXCH is allocated to the terminal apparatus that has not received the EXCH allocation based on the transmission capacity. In step S15, it is confirmed whether or not there is an unallocated radio resource area, that is, an empty area, for the four uplink slots managed by the base station. The EXCH is allocated to the terminal apparatus having the bandwidth allocation request by repeating the above operation. If there is no free area, the EXCH allocation is terminated.

  On the other hand, when there is a terminal device having a slot in which “0” is set in the response bit, the EXCH of the terminal device is assigned. In this case, since it is possible to increase the allocation of PRUs in the frequency direction in the terminal device, when the terminal device next transmits a response bit, the frequency is set so that the response bit becomes “1”. Assign to increase the PRU assignment in the direction.

  Thereafter, in step S15, it is confirmed whether or not there is an unallocated radio resource area, that is, an empty area, for the four uplink slots managed by the base station. If there is an empty area, step S11 is performed. The following operations are repeated to allocate EXCH to a terminal device that has a bandwidth allocation request. If there is no free area, the allocation of EXCH is terminated.

  The above operation will be schematically described with reference to FIG. Of the four slots, the condition that slot 4 is an area that cannot be allocated to terminal apparatus A and slot 1 is an area that cannot be allocated to terminal apparatus B is the first condition. As explained.

  FIG. 9A shows an example in which bandwidth allocation is performed in accordance with a bandwidth allocation request from the terminal device A, and the terminal device A requests allocation of data corresponding to nine PRUs. This allocation is a case where the response bits from the terminal device A are determined to be “1” in any slot (corresponding to the processing in step S12 in FIG. 8). This is equivalent to the allocation in the case where it is determined that only PRU data can be transmitted and band allocation is performed so that the PRUs of subchannels 1 to 3 are used for each of slots 1 to 3 (FIG. 8). Equivalent to the processing in step S14).

  In the part (b) of FIG. 9, when the response bit is confirmed in response to the bandwidth allocation request from the terminal device A (corresponding to the process of step S12 of FIG. 8), the response bit of the terminal device A includes the slot 1 4 shows the assignment when the response bits of “2” and “2” are set, and all four PRUs are assigned to the terminal device A in the slots 1 and 2, and the PRU of the subchannel 1 in the slot 3 is assigned. Is assigned to the terminal device A. As a result, the remaining seven PRUs can be allocated to the terminal device B.

  In this way, when performing PRU allocation in response to a bandwidth allocation request from the terminal device, the response bit is confirmed sequentially, and if there is a slot in which “0” is set in the response bit, the response bit is used. Thus, by increasing the frequency-direction PRU allocation to the terminal device and decreasing the time-direction PRU allocation, it is possible to optimize the PRU allocation and perform efficient band allocation.

  Note that when performing PRU allocation, the allocation is performed by sequentially checking response bits, so that the time spent for allocation can be shortened compared to the case where the allocation once determined is changed.

<Third example of radio resource allocation optimization>
Next, a third example of radio resource allocation optimization in the base station will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a flowchart showing PRU allocation operation for transmitting EXCH at the base station.

  In FIG. 10, when the allocation of EXCH is started, the base station transmits the allocation of EXCH (for transmitting the EXCH in the order in which the request is received) to the terminal device that has transmitted the bandwidth allocation request using the RCH of the physical header of the ECCH. PRU allocation).

  First, it is confirmed whether or not the allocation of EXCH has been completed for all the terminal devices that have transmitted the bandwidth allocation request (step S21). If the allocation has been completed, the allocation of EXCH is terminated. If there is a terminal device that has not been assigned an EXCH, the process proceeds to step S22, where the response bit of the terminal device that requests the assignment is confirmed, and whether there is a slot in which “0” is set in the response bit. Determine.

  Here, if there is no slot in which “0” is set in the response bit, the process proceeds to step S24, and EXCH allocation is performed based on the transmission capacity to a terminal apparatus that has not received EXCH allocation. Then, in step S25, it is confirmed whether or not there is an unallocated radio resource area, that is, an empty area, for the four uplink slots managed by the base station. By repeating the above operation, the EXCH is allocated to the terminal device having the bandwidth allocation request.

  On the other hand, if there is no free area, the process proceeds to step S26, where the response bit of the terminal device to which EXCH has been allocated so far is confirmed, and the terminal device having a slot in which “0” is set in the response bit. It is determined whether or not there is. Here, if there is no terminal device having a slot in which “0” is set in the response bit, the EXCH allocation is terminated on the assumption that no more EXCH allocation is possible, but “0” is set in the response bit. If there is a terminal device having the designated slot, the EXCH assignment of the terminal device is reviewed. As a result, after the free space is secured, the operations in step S21 and subsequent steps are repeated, and EXCH is allocated to the terminal device having a bandwidth allocation request.

  On the other hand, if it is determined in step S22 that there is a terminal apparatus having a slot in which “0” is set in the response bit, EXCH allocation of the terminal apparatus is performed (step S23). In this case, since it is possible to increase the allocation of PRUs in the frequency direction in the terminal device, when the terminal device next transmits a response bit, the frequency is set so that the response bit becomes “1”. Assign to increase the PRU assignment in the direction.

  Thereafter, in step S25, it is confirmed whether or not there is an unallocated radio resource area, that is, an empty area, for the four uplink slots managed by the base station. If an empty area exists, step S21 is performed. The following operations are repeated to allocate EXCH to a terminal device that has a bandwidth allocation request.

  On the other hand, if there is no free area, the process proceeds to step S26, where the response bit of the terminal device to which EXCH has been allocated so far is confirmed, and the terminal device having a slot in which “0” is set in the response bit. It is determined whether or not there is. Here, if there is no terminal device having a slot in which “0” is set in the response bit, the EXCH allocation is terminated on the assumption that no more EXCH allocation is possible, but “0” is set in the response bit. If there is a terminal device having the designated slot, the EXCH assignment of the terminal device is reviewed. As a result, after the free space is secured, the operations in step S21 and subsequent steps are repeated, and EXCH is allocated to the terminal device having a bandwidth allocation request.

  The above operation will be schematically described with reference to FIG. In FIG. 11, description will be made assuming that there is a bandwidth allocation request from three terminal devices, terminal device A, terminal device B, and terminal device C. Of the four slots, the condition that the slot 4 is an area that cannot be allocated to the terminal apparatus A and the slot 1 is an area that cannot be allocated to the terminal apparatus B is the first condition. As described above, the terminal device C has a condition that the subchannel 4 of each slot cannot be allocated.

  FIG. 11A shows an example in which bandwidth allocation is performed in accordance with a bandwidth allocation request from the terminal device A, and the terminal device A requests allocation of data corresponding to nine PRUs. This allocation is a case where the response bits from the terminal device A are determined to be “1” in any slot (corresponding to the process of step S22 in FIG. 10), and 3 in one slot from the transmission capacity. This is equivalent to the allocation when it is determined that only PRU data can be transmitted and band allocation is performed so that the PRUs of subchannels 1 to 3 are used for each of slots 1 to 3 (step in FIG. 10). Equivalent to the process of S24).

  In the part (b) of FIG. 11, when the response bit is confirmed in response to the bandwidth allocation request from the terminal device A (corresponding to the process of step S22 in FIG. 10), the response bit of the terminal device A includes the slot 1 4 shows the assignment when the response bits of “2” and “2” are set, and all four PRUs are assigned to the terminal device A in the slots 1 and 2, and the PRU of the subchannel 1 in the slot 3 is assigned. Is assigned to the terminal device A, the next time the terminal device transmits a response bit, the allocation is performed by increasing the PRU allocation in the frequency direction so that the response bit becomes “1” ( This corresponds to the process of step S23 in FIG. 10).

  After performing such allocation, it is confirmed whether or not there is an empty area for the four slots (corresponding to the process of step S25 in FIG. 10). The response bit is confirmed for the terminal device B having the bandwidth allocation request (corresponding to step S22 in FIG. 10).

  In this determination, the response bit from the terminal device B is determined to be “1” in any slot, and it is determined from the transmission capacity that only two PRUs of data can be transmitted in one slot. As shown in part (b) of FIG. 11, two PRUs in slots 3 and 4 are allocated to terminal device B by two (corresponding to the process of step S24 in FIG. 10).

  After performing such allocation, it is confirmed whether or not there is an empty area for the four slots (corresponding to the process of step S25 in FIG. 10). The response bit is confirmed for the terminal device C having the bandwidth allocation request (corresponding to step S22 in FIG. 10).

  In this determination, since it is determined that the response bit from the terminal device C is “1” in all slots, the allocation is performed based on the transmission capacity (corresponding to the process of step S24 in FIG. 10).

  Here, it is determined that the terminal apparatus C can transmit only two PRUs of data in one slot from the transmission capacity, but the terminal apparatus C requests allocation of data corresponding to two PRUs. Therefore, although it can be assigned to the terminal device C in terms of the number of free areas, the subchannel 4 of each slot cannot be assigned to the terminal device C.

  Therefore, only the PRU of the subchannel 3 in slot 4 can be allocated to the terminal device C, and it is determined that the allocation request of the terminal device C cannot be satisfied and there is no free area (see FIG. 10 equivalent to the processing of step S25).

  On the other hand, the response bit of the terminal apparatus B that has already been assigned the EXCH is confirmed, and it is determined whether or not it has a slot in which “0” is set in the response bit (in the process of step S26 in FIG. 10). Equivalent).

  Here, in step S23, the response bit of the terminal device B has been determined to be “1” in any slot, but “0” is set in the response bit of slot 3 as a result of redetermination. found. That is, according to the transmission capacity of the terminal device B, it is determined that only two PRUs of data can be transmitted in one slot, but the response bit set based on the actual value of the transmission capacity is “0”. Therefore, since it is determined that data transmission for three PRUs in one slot is possible, the base station reviews the assignment of EXCH assigned to the terminal device B (processing in step S27 in FIG. 10). Equivalent).

  As a result, as shown in part (c) of FIG. 11, the PRUs of subchannels 2 to 4 are assigned to terminal device B in slot 3, and the PRUs of subchannel 1 of slot 4 are assigned to terminal device B. By doing so, it becomes possible to allocate the PRUs of the subchannels 2 and 3 in the slot 4 to the terminal device C and satisfy the allocation request of the terminal device C.

  In this way, when performing PRU allocation in response to a bandwidth allocation request from the terminal device, the response bits are sequentially confirmed. If there is a slot in which “0” is set, based on the response bits, By increasing the frequency-direction PRU allocation to the terminal device and decreasing the time-direction PRU allocation, it is possible to optimize the PRU allocation and perform efficient band allocation.

  Further, by increasing the PRU allocation in the frequency direction for the terminal device based on the response bit of the terminal device that has already performed the PRU allocation, it is possible to prevent the appearance of a terminal device in which the PRU allocation is not optimized. .

<Device configuration>
FIG. 12 is a diagram illustrating a configuration of the wireless communication system 100 according to the present invention, and the base station 11 and the terminal device 12 correspond to the base station and the terminal device described in the embodiment.

  In the wireless communication system 100, the base station 11 performs wireless communication with a plurality of terminal devices 12 by the OFDMA method or the TDMA / TDD method (Time Division Multiple Access / Time Division Duplexing).

  In the OFDMA scheme, an OFDM (Orthogonal Frequency Division Multiplexing) signal in which a plurality of subcarriers orthogonal to each other are combined is used. The base station 11 can simultaneously communicate with the plurality of terminal devices 12 by individually allocating radio resources specified in two dimensions including a time axis and a frequency axis to each of the plurality of terminal devices 12. It has become.

  The base station 11 is wired to the network NW via an optical fiber or the like. The base station 11 transmits data received from the terminal device 12 to the network NW, and transmits data received from the network NW to the terminal device 12.

  FIG. 13 is a block diagram showing the configuration of the base station 11. As illustrated in FIG. 13, the base station 11 includes a wireless communication unit 111 that performs wireless communication, a network connection unit 112 that performs communication with a network NW, a storage unit 113 that stores various types of information, a wireless communication unit 111, The network connection part 112 and the control part 114 which controls the memory | storage part 113 are provided.

  The wireless communication unit 111 acquires data from the OFDM signal received by the array antenna 110 configured by the plurality of antenna elements 110 a and outputs the data to the control unit 114. In addition, the wireless communication unit 111 generates an OFDM signal including transmission data input from the control unit 114 and wirelessly transmits it from the array antenna 110.

  The network connection unit 112 is connected to the network NW by, for example, an optical fiber. The network connection unit 112 transmits data input from the control unit 114 to the network NW and outputs data input from the network NW to the control unit 114.

  The control unit 114 is configured by, for example, a CPU (Central Processing Unit). When the CPU of the control unit 114 executes the operation program stored in the storage unit 113, various functional blocks such as a bandwidth allocation request accepting unit 1141 and a bandwidth allocation control unit 1142 are realized in the control unit 114. .

  This bandwidth allocation request accepting unit 1141 is a functional block that accepts bandwidth allocation requests from the terminal device 12 and processes them in the order received, or changes the order by setting priorities.

  The band allocation control unit 1142 is a functional block that executes the PRU allocation operation described with reference to FIGS. 3, 8, and 10.

  FIG. 14 is a block diagram illustrating a configuration of the terminal device 12. As illustrated in FIG. 14, the terminal device 12 includes a wireless communication unit 121 that performs wireless communication via an antenna AT, a system control unit 122, and a storage unit 123.

  The radio communication unit 121 receives a radio signal from the base station 11 or the like with the antenna AT, performs amplification processing or down-conversion on the received signal, outputs the signal to the system control unit 122, and generates it with the system control unit 122 The converted transmission signal is up-converted and amplified, and the processed transmission signal is transmitted to the base station 11 and the like through the antenna AT.

  The system control unit 122 is composed of, for example, a CPU. When the CPU of the system control unit 122 executes the operation program stored in the storage unit 123, various function blocks such as a bandwidth allocation request creation unit 1221 are realized in the system control unit 122.

  In this bandwidth allocation request creation unit 1221, a bandwidth allocation request using the RCH of the ECCH physical header, a calculation of a transmission capacity, a notification of a transmission capacity using the RCH of the ECCH physical header, and a description using FIG. Then, the actual value of the transmission capacity is calculated and a response bit using the RCH of the physical header of the ECCH is created.

11 Base Station 12 Terminal Device 1141 Band Allocation Request Accepting Unit 1142 Band Allocation Control Unit 1221 Band Allocation Request Creating Unit

Claims (12)

A base station that performs wireless communication with a terminal device,
A bandwidth allocation request for requesting radio resource allocation to the base station from the terminal device is made,
The base station
A bandwidth allocation request receiving unit that receives the bandwidth allocation request;
A bandwidth allocation control unit that performs allocation of radio resources based on the bandwidth allocation request,
The bandwidth allocation control unit
Receiving information on whether or not it is possible to increase the transmission capacity and the number of radio resources transmitted from the terminal device using the channel used for the band allocation request in the frequency direction, the number of radio resources is set to the frequency. If it is determined that it can be increased in the direction, change the allocation of the already allocated radio resources to increase in the frequency direction and decrease in the time direction, or change the allocation of radio resources to be allocated in the frequency direction from now on. A base station configured to increase the number and decrease the number in the time direction.   The information as to whether or not the number of radio resources can be increased in the frequency direction is given by a response bit representing in binary whether or not the number of radio resources can be increased in the frequency direction. Item 1. The base station according to Item 1. The transmission capacity is
Obtained by subtracting the transmission power of the radio resource for control from the maximum transmission output of the terminal device,
The response bit is
It is set based on the actual value of the transmission capacity obtained by subtracting the transmission power of the control radio resource and the transmission power of the data radio resource from the maximum transmission output of the terminal device, and the actual value of the transmission capacity is positive. 3, the base station according to claim 2, wherein the base station is set to a value indicating that the number of radio resources can be increased in the frequency direction.   The base station according to claim 2, wherein the response bit is set for each of the four slots constituting the uplink. The bandwidth allocation control unit
After assigning radio resources based on the transmission capacity, if there are no unassigned radio resources, refer to the response bits from the terminal device to which radio resources have already been assigned, and the response bits 3. When the number of resources is set to a value that can be increased in the frequency direction, the allocation of already allocated radio resources is changed to be increased in the frequency direction and decreased in the time direction. base station. The bandwidth allocation control unit
The response bit from the terminal device is referred to, and when the response bit is set to a value capable of increasing the number of radio resources in the frequency direction, the allocation of radio resources to be allocated is determined in the frequency direction. The base station according to claim 2, wherein the number is set so as to increase the number of and decrease the number in the time direction. A terminal device that performs wireless communication with a base station,
The terminal device
A bandwidth allocation request creating unit for creating a bandwidth allocation request for requesting radio resource allocation to the base station;
The bandwidth allocation request creating unit
A terminal device that generates information about whether or not the transmission capacity and the number of radio resources can be increased in the frequency direction, and transmits the information to the base station using a channel used for the band allocation request.   Information about whether or not the number of radio resources can be increased in the frequency direction is created as a response bit that represents in binary whether or not the number of radio resources can be increased in the frequency direction. The terminal device according to claim 7. The transmission capacity is
Obtained by subtracting the transmission power of the radio resource for control from the maximum transmission output of the terminal device,
The response bit is
It is set based on the actual value of the transmission capacity obtained by subtracting the transmission power of the control radio resource and the transmission power of the data radio resource from the maximum transmission output of the terminal device, and the actual value of the transmission capacity is positive. Is set to a value indicating that the number of radio resources can be increased in the frequency direction.   The terminal device according to claim 8, wherein the response bit is set for each of four slots constituting the uplink. A terminal device and a base station,
A bandwidth allocation request for requesting radio resource allocation to the base station from the terminal device is made,
The base station
A bandwidth allocation request receiving unit that receives the bandwidth allocation request;
A bandwidth allocation control unit that performs allocation of radio resources based on the bandwidth allocation request,
The bandwidth allocation control unit
With reference to the information about whether or not it is possible to increase the transmission capacity sent from the terminal device using the channel used for the bandwidth allocation request and the number of radio resources in the frequency direction,
If it is determined from the above information that the number of radio resources can be increased in the frequency direction, change the allocation of already allocated radio resources in the frequency direction and decrease in the time direction, or Set the allocation of radio resources to be increased in the frequency direction and the number in the time direction,
The terminal device
A bandwidth allocation request creating unit for creating a bandwidth allocation request for requesting radio resource allocation to the base station;
The bandwidth allocation request creating unit
A radio communication system that creates information about whether or not the transmission capacity and the number of radio resources can be increased in the frequency direction, and transmits the information to the base station using a channel used for the band allocation request.   Information about whether or not the number of radio resources can be increased in the frequency direction is created as a response bit that represents in binary whether or not the number of radio resources can be increased in the frequency direction. The wireless communication system according to claim 11.

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