JP5312161B2 - Radio base station, radio resource allocation method, and radio communication system - Google Patents

Description

  The present invention relates to a radio base station, a radio resource allocation method, and a radio communication system.

  As a conventional wireless communication system, scheduling information including a data size waiting for transmission and a difference information Ph (Power Headroom) of current transmission power with respect to the maximum transmission power that can be transmitted is transmitted from the wireless terminal to the wireless base station. Based on this scheduling information, a radio base station determines the transmission power of the radio terminal and performs scheduling for controlling the data rate of transmission.

  Recently, for example, standardization of LTE (Long Term Evolution) is being promoted in 3GPP (3rd Generation Partnership Project). In LTE, a transmission band (resource block) having a plurality of subcarriers is allocated as an uplink radio resource (see, for example, Non-Patent Document 1). Therefore, in LTE, similarly to the conventional radio communication system, the radio base station determines the transmission power of the radio terminal based on the scheduling information including the difference information Ph from the radio terminal, and sets the transmission data rate. It is assumed that scheduling to control is performed.

3GPP TR25.814

  By the way, in a wireless communication system that performs communication by allocating wireless resources of different frequencies to a plurality of wireless terminals, the wireless state changes from time to time for each wireless resource due to the influence of frequency selective fading and the like. There may be a good radio resource and a radio resource in which the radio state is deteriorated. In this case, for the wireless terminal using the wireless resource whose wireless state has deteriorated, as described above, the transmission power is determined based on the difference information Ph from the wireless terminal, and the transmission data rate is set. By performing scheduling for control, it is possible to ensure desired communication quality.

  However, if there is no margin in the transmission power of the wireless terminal, when the wireless state of the wireless resource assigned to the wireless terminal is further deteriorated, it is no longer possible to control to increase the transmission power, and wireless communication with the wireless base station It becomes difficult to maintain the link. On the other hand, in general, a radio terminal using a radio resource with a good radio state generally has a margin in transmission power.

  Thus, in a wireless communication system that performs communication by allocating wireless resources of different frequencies to a plurality of wireless terminals, even if the transmission power is controlled based on the difference information Ph from the wireless terminal in the wireless base station, Depending on the wireless terminal, there is a concern that it may be difficult to maintain a wireless link with the wireless base station because there is no margin in transmission power.

  Accordingly, an object of the present invention made in view of such a point is to provide a radio base station, a radio resource allocation method, and a radio communication system that can appropriately control transmission power of a plurality of radio terminals and can stably maintain a radio link. It is to provide.

The invention of the radio base station according to the first aspect of achieving the above object is as follows:
In a radio base station that performs radio communication by assigning different radio resources to a plurality of radio terminals,
A measurement unit that measures a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
A difference information acquisition unit for acquiring difference information of a current transmission power with respect to a maximum transmission power transmitted from each of the plurality of wireless terminals;
A communication type information acquisition unit for acquiring communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the propagation loss in each radio resource measured by the measurement unit, the plurality of radio resources are classified into at least two radio resource groups, and for each of the plurality of radio terminals, the difference information acquisition unit A control unit that controls to allocate radio resources of the corresponding radio resource group based on the difference information acquired in step 1 and the communication type information acquired by the communication type information acquisition unit;
It is characterized by providing.

The invention according to the second aspect is the radio base station according to the first aspect,
The controller is
Classifying the plurality of radio resources into at least two or more radio resource groups based on a comparison between a propagation loss in each radio resource measured by the measurement unit and a preset threshold;
It is characterized by this.

The invention according to a third aspect is the radio base station according to the first or second aspect,
The controller is
After determining the radio resource group to which radio resources are allocated based on the difference information acquired by the difference information acquisition unit for each radio terminal, based on the communication type information acquired by the communication type information acquisition unit And, in the determined radio resource group, control is performed so as to allocate a radio resource having a relatively large or small propagation loss measured by the measurement unit,
It is characterized by this.

The invention according to a fourth aspect is the radio base station according to the first or second aspect,
The controller is
After determining the radio resource group to which radio resources are allocated based on the communication type information acquired by the communication type information acquisition unit for each radio terminal, based on the difference information acquired by the difference information acquisition unit And, in the determined radio resource group, control is performed so as to allocate a radio resource having a relatively large or small propagation loss measured by the measurement unit,
It is characterized by this.

Furthermore, the invention of the radio resource allocation method according to the fifth aspect of achieving the above object,
A radio resource allocation method in a radio base station that performs radio communication by allocating different radio resources to a plurality of radio terminals,
Measuring a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
Obtaining difference information of current transmission power with respect to maximum transmission power transmitted from each of the plurality of wireless terminals;
Obtaining communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the measured propagation loss in each radio resource, classify the plurality of radio resources into at least two radio resource groups, and for each of the plurality of radio terminals, the acquired difference information and the Controlling to allocate the radio resource of the corresponding radio resource group based on the acquired communication type information;
It is characterized by including.

Furthermore, the invention of the wireless communication system according to the sixth aspect of achieving the above object is
In a wireless communication system in which different wireless resources are allocated to a plurality of wireless terminals by a wireless base station, and wireless communication is performed between the wireless base station and the plurality of wireless terminals,
Each of the plurality of wireless terminals is
A calculation unit that calculates a difference between the current transmission power and the maximum transmission power that can be transmitted by the wireless terminal, and outputs difference information;
A transmission unit for transmitting the difference information output from the calculation unit to the radio base station,
The radio base station is
A measurement unit that measures a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
A difference information acquisition unit for acquiring difference information of a current transmission power with respect to a maximum transmission power transmitted from each of the plurality of wireless terminals;
A communication type information acquisition unit for acquiring communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the propagation loss in each radio resource measured by the measurement unit, the plurality of radio resources are classified into at least two radio resource groups, and for each of the plurality of radio terminals, the difference information acquisition unit A control unit that controls to allocate a radio resource of the corresponding radio resource group based on the difference information acquired in step 1 and the communication type information acquired by the communication type information acquisition unit.
It is characterized by this.

  In the present invention, at a predetermined timing, the base station measures the propagation state in a plurality of radio resources, classifies the plurality of radio resources into two or more radio resource groups based on the propagation state, and each radio terminal On the other hand, based on the acquired difference information and communication type information, control is performed so that the radio resources of the corresponding radio resource group are allocated. Therefore, it is possible to appropriately control the transmission power of a plurality of wireless terminals, and it is possible to stably maintain the wireless link between each wireless terminal and the wireless base station.

It is a figure which shows schematic structure of the radio | wireless communications system which has a radio base station which concerns on 1st Embodiment of this invention. 3 is a flowchart showing radio resource block allocation scheduling operation by the radio base station shown in FIG. 1. FIG. 2 is a schematic diagram showing radio resource block allocation by the radio base station shown in FIG. 1. It is a flowchart which shows the allocation scheduling operation | movement of the radio | wireless resource block by the radio base station which concerns on 2nd Embodiment of this invention.

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

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a radio communication system having a radio base station according to the first embodiment of the present invention. This radio communication system is based on, for example, LTE, and a radio base station 10 according to the present embodiment assigns different radio resource blocks to a plurality of radio terminals 20 (only one is shown in FIG. 1). Allocating and performing wireless communication between the wireless base station 10 and the plurality of wireless terminals 20.

  The radio base station 10 includes a radio communication unit 11, a propagation loss measurement unit 12, a Ph acquisition unit 13, a communication type information acquisition unit 14, and a control unit 15. The wireless communication unit 11 performs wireless communication with a plurality of wireless terminals 20. The propagation loss measurement unit 12 measures the propagation loss in each radio resource block assigned to the plurality of radio terminals 20 at predetermined timing based on the received signal obtained from the radio communication unit 11, and the measurement result Is supplied to the control unit 15.

  Here, the predetermined timing for measuring the propagation loss is, for example, a processing unit time defined by the system, for example, a subframe (1 ms) in a radio frame. Further, the propagation loss is measured based on, for example, the received electric field strength and packet loss in each radio resource block.

  The Ph acquisition unit 13 constitutes a difference information acquisition unit, and acquires the difference information Ph of the current transmission power with respect to the maximum transmission power transmitted from each wireless terminal 20 based on the reception signal obtained from the wireless communication unit 11. Then, the acquired difference information Ph is supplied to the control unit 15.

  The communication type information acquisition unit 14 recognizes the type of communication with each wireless terminal 20, acquires the communication type information, and supplies the communication type information to the control unit 15. In the present embodiment, the communication type information acquisition unit 14 determines the communication type information as a communication type (T1) for which real-time performance such as voice communication or streaming is required, and other communication types for data communication such as browsing ( And is supplied to the control unit 15.

  The control unit 15 controls the operation of the entire radio base station, and at each predetermined timing, the propagation loss measured by the propagation loss measurement unit 12, the difference information Ph acquired by the Ph acquisition unit 13, and the communication type information Based on the communication type information acquired by the acquisition unit 14, the radio resource block allocation to a plurality of radio terminals 20 is controlled (scheduled), and the result is transmitted to the corresponding radio terminal 20 via the radio communication unit 11. To do.

  In the radio base station 10, the propagation loss measurement unit 12, the Ph acquisition unit 13, the communication type information acquisition unit 14, and the control unit 15 are configured by one CPU (central processing unit). You may comprise so that each process of the propagation loss measurement part 12, the Ph acquisition part 13, the communication classification information acquisition part 14, and the control part 15 may be shared and performed by several CPU.

  On the other hand, each wireless terminal 20 includes a wireless communication unit 21, a Ph calculation unit 22, and a control unit 23. The radio communication unit 21 includes a transmission unit and a reception unit, and performs communication with the radio base station 10 using the allocated radio resource block. The Ph calculation unit 22 calculates the difference between the current transmission power and the maximum transmission power that can be transmitted by the wireless terminal 20, and supplies the difference information Ph to the control unit 23. The control unit 23 controls the operation of the entire wireless terminal, and the difference information Ph obtained from the Ph calculation unit 22 is transmitted via the wireless communication unit 21 periodically or at a timing requested from the wireless base station 10. To transmit (notify) to the radio base station 10.

  FIG. 2 is a flowchart showing a radio resource block allocation scheduling operation by radio base station 10 according to the present embodiment. The control unit 15 acquires the propagation loss of all radio resource blocks from the propagation loss measurement unit 12 at every predetermined timing (step S11). Then, the control unit 15 classifies the plurality of radio resource blocks into a plurality of radio resource groups based on a comparison between the acquired propagation loss of each radio resource block and a preset threshold value. In this embodiment, the propagation loss threshold is one, and the propagation loss is less than the threshold, that is, the group A in which the radio state is good, and the propagation loss is greater than the threshold, that is, the group B in which the radio state is relatively bad. Classify into radio resource groups (step S12).

  Further, the control unit 15 acquires the difference information Ph of each wireless terminal 20 from the Ph acquisition unit 13 at every predetermined timing (step S13), and the communication of each wireless terminal 20 classified from the communication type information acquisition unit 14 Type information is acquired (step S14).

  And the control part 15 compares the difference information Ph of the said radio | wireless terminal 20, and the preset threshold Phref with respect to each radio | wireless terminal 20 (step S15). As a result, in the case of Ph <Phref, there is no transmission power, so the control unit 15 further determines whether or not the communication type of the wireless terminal 20 is the communication type T1 that requires real-time performance. (Step S16).

  As a result, when the communication type is T1, the control unit 15 preferentially assigns a radio resource block with a smaller propagation loss among the radio resource blocks of the group A to the radio terminal 20. Block allocation is scheduled (step S17), and the result is transmitted to the corresponding radio terminal 20.

  On the other hand, when the communication type is T2, real-time performance is not required, so the control unit 15 allocates a radio resource block with a large propagation loss among the radio resource blocks of group A to the radio terminal 20. Thus, the allocation of radio resource blocks is scheduled (step S18), and the result is transmitted to the corresponding radio terminal 20.

  On the other hand, if Ph ≧ Phref in Step S15, there is a margin in transmission power, so the control unit 15 determines whether or not the communication type is T1 (Step S19). The radio resource block is scheduled to be allocated so as to preferentially allocate a radio resource block with a small propagation loss among the radio resource blocks of group B to the radio terminal 20 (step S20), and the result corresponds to the result. Transmit to the wireless terminal 20.

  On the other hand, in the case of communication type T2, the control unit 15 assigns radio resource blocks to the radio terminal 20 so that radio resource blocks having a large propagation loss among radio resource blocks of group B are assigned. Scheduling is performed (step S21), and the result is transmitted to the corresponding wireless terminal 20.

  In this way, the control unit 15 assigns the radio resource block to be assigned to each radio terminal 20 at each predetermined timing according to the radio status of each radio resource block that changes from time to time. Scheduling is performed according to the difference information Ph of the wireless terminal and the communication type.

  FIG. 3 is a schematic diagram showing radio resource block allocation by the radio base station 10 according to the present embodiment. In FIG. 3, the horizontal axis indicates time and the vertical axis indicates frequency. The processing unit time corresponds to a predetermined timing for scheduling the allocation of radio resource blocks. As is apparent from FIG. 3, the allocation state of the radio resource blocks to the plurality of radio terminals indicated by the users 1 to n is the radio status of each radio resource block and each radio terminal in sequential processing unit time (predetermined timing). Is changed according to the difference information Ph and the communication type. FIG. 3 shows a case where one radio resource block is allocated to each user (wireless terminal). However, when the number of connected terminals is small, a plurality of radio resource blocks are allocated to one radio terminal. There is also a case of scheduling.

  According to the radio communication system having the radio base station 10 according to the present embodiment, the radio terminal 20 having a margin of transmission power whose difference information Ph is less than the threshold Phref has a small propagation loss, that is, in a radio state. For the wireless terminal 20 that performs communication of the communication type T1 in which a radio resource block of a good group A is selected and requires real-time property, the propagation loss is small in the group A, that is, the wireless state A good radio resource block is preferentially allocated. Therefore, a wireless link can be more stably maintained with respect to the wireless terminal 20 performing communication of the communication type T1, and QoS (Quality of Service) of the communication type T1 can be ensured.

  Further, for the radio terminal 20 having the difference information Ph exceeding the threshold Phref, the radio resource block of the group B having a large propagation loss, that is, the radio condition is bad, is selected. Therefore, the radio link can be maintained by appropriately controlling the transmission power. Moreover, in this case as well, a radio resource block having a small propagation loss in the group B, that is, a radio resource block having a good radio state is given priority to the radio terminal 20 performing communication of the communication type T1 requiring real-time performance. Therefore, QoS of the communication type T1 can be secured more stably.

  Therefore, according to the radio communication system having the radio base station 10 according to the present embodiment, it is possible to appropriately control the transmission power of each radio terminal 20 and to stabilize the radio link between each radio terminal 20 and the radio base station 10. Can be maintained. In addition, since the radio base station 10 can know the propagation loss of all radio resource blocks at every predetermined timing, the radio base station 10 follows the temporal change in the radio state, and performs the downlink modulation scheme, antenna beamforming, etc. It is also possible to control.

(Second Embodiment)
The radio base station according to the second embodiment of the present invention has a radio resource block of group A with a small propagation loss for the radio terminal 20 of the communication type T1 that requires real-time performance in the configuration shown in FIG. The radio resource block allocation is scheduled so as to be allocated.

  FIG. 4 is a flowchart showing radio resource block allocation scheduling operation by the radio base station according to the present embodiment. The operation will be described below with reference to FIG. As in the case of the first embodiment, the control unit 15 acquires the propagation loss of all radio resource blocks from the propagation loss measuring unit 12 at every predetermined timing (step S31), and propagates the radio resource block. Classification is made into two radio resource groups, group A with a loss less than the threshold and group B with a propagation loss greater than or equal to the threshold (step S32).

  Further, the control unit 15 acquires the difference information Ph of each wireless terminal 20 from the Ph acquisition unit 13 at every predetermined timing (step S33), and the communication of each wireless terminal 20 classified from the communication type information acquisition unit 14 Type information is acquired (step S34).

  Then, for each wireless terminal 20, the control unit 15 first determines whether the communication type of the wireless terminal 20 is a communication type T1 for which real-time property is required, as opposed to the case of the first embodiment. It is determined whether or not (step S35). As a result, in the case of the communication type T1, the control unit 15 further compares the difference information Ph of the wireless terminal 20 with a preset threshold Phref in order to reliably maintain the wireless link (step S36).

  As a result, when Ph> Phref, there is a margin in transmission power, so the control unit 14 has a radio resource block with a large propagation loss among the radio resource blocks of group A with a small propagation loss with respect to the radio terminal 20. So that radio resource blocks are allocated (step S37), and the result is transmitted to the corresponding radio terminal 20.

  On the other hand, when Ph ≦ Phref, since there is no margin in transmission power, the control unit 15 gives priority to a radio resource block with a smaller propagation loss among the radio resource blocks of group A to the radio terminal 20. The radio resource block is scheduled to be allocated (step S38), and the result is transmitted to the corresponding radio terminal 20.

  On the other hand, when the communication type is the communication type T2 that does not require real-time property in step S35, the control unit 15 compares the difference information Ph with the threshold Phref (step S39), and if Ph> Phref, the wireless The allocation of radio resource blocks is scheduled so as to allocate radio resource blocks having a large propagation loss among radio resource blocks of group B to the terminal 20 (step S40), and the result is sent to the corresponding radio terminal 20 Send.

  On the other hand, in the case of Ph ≦ Phref, the control unit 15 preferentially assigns a radio resource block with a small propagation loss among the radio resource blocks of the group B to the radio terminal 20. Is assigned (step S41), and the result is transmitted to the corresponding wireless terminal 20.

  In this way, the control unit 15 assigns the radio resource block to be assigned to each radio terminal 20 at each predetermined timing according to the radio status of each radio resource block that changes from time to time. Scheduling is performed according to the communication type of the wireless terminal and the difference information Ph.

  According to the wireless communication system having the wireless base station 10 according to the present embodiment, the wireless terminal 20 performing communication of the communication type T1 requiring real-time performance has a small propagation loss, that is, a wireless state. Since a good radio resource block of group A is selected, QoS for each communication type can be secured. In addition, when the communication type T1 and the difference information Ph is Ph ≦ Phref, the radio resource block with the smaller propagation loss is preferentially allocated among the radio resource blocks of the group A. Therefore, in the case of the first embodiment Similarly, it is possible to maintain a wireless link more stably for the wireless terminal 20 performing communication of the communication type T1, and to secure QoS of the communication type T1.

  For the wireless terminal 20 performing communication of the communication type T2, the wireless resource block of group B is selected, but for the wireless terminal 20 having no margin for transmission power whose difference information Ph is equal to or less than the threshold Phref. Therefore, among the radio resource blocks of group B, radio resource blocks with a small propagation loss are preferentially allocated, and for radio terminals 20 having sufficient transmission power that the difference information Ph exceeds the threshold Phref, group B Among these radio resource blocks, radio resource blocks with large propagation loss are allocated, so that the radio link can be stably maintained.

  Thereby, similarly to the case of the radio communication system having the radio base station 10 according to the first embodiment, the transmission power of each radio terminal 20 can be appropriately controlled, and each radio terminal 20 and the radio base station 10 can be controlled. A radio link can be maintained stably. In addition, since the radio base station 10 can know the propagation loss of all radio resource blocks at every predetermined timing, the radio base station 10 follows the temporal change in the radio state, and performs the downlink modulation scheme, antenna beamforming, etc. It is also possible to control.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible. For example, in the above embodiment, the radio resource blocks are classified into two radio resource groups. However, a plurality of thresholds can be set for propagation loss, and the radio resource blocks can be classified into three or more radio resource groups. Similarly, the communication type is not limited to two, and can be classified into three or more. In this way, if the radio resource group is classified into three or more or the communication type is classified into three or more, the radio resource block for each radio terminal is determined according to the difference information Ph and the communication type of the radio terminal. Therefore, it is possible to schedule more appropriately and efficiently.

  The present invention is not limited to LTE, and is different for each of a plurality of wireless terminals such as WiMAX (Worldwide Interoperability for Microwave Access), UMB (Ultra Mobile Broadband), next-generation PHS (Personal Handy-phone System), IMT-Advanced, etc. The present invention can be widely applied to a wireless communication system that performs wireless communication by allocating wireless resources.

DESCRIPTION OF SYMBOLS 10 Radio base station 11 Wireless communication part 12 Propagation loss measurement part 13 Ph acquisition part 14 Communication type information acquisition part 15 Control part 20 Wireless terminal 21 Wireless communication part 22 Ph calculation part 23 Control part

Claims (6)

In a radio base station that performs radio communication by assigning different radio resources to a plurality of radio terminals,
A measurement unit that measures a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
A difference information acquisition unit for acquiring difference information of a current transmission power with respect to a maximum transmission power transmitted from each of the plurality of wireless terminals;
A communication type information acquisition unit for acquiring communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the propagation loss in each radio resource measured by the measurement unit, the plurality of radio resources are classified into at least two radio resource groups, and for each of the plurality of radio terminals, the difference information acquisition unit A control unit that controls to allocate radio resources of the corresponding radio resource group based on the difference information acquired in step 1 and the communication type information acquired by the communication type information acquisition unit;
A radio base station comprising: The controller is
Classifying the plurality of radio resources into at least two or more radio resource groups based on a comparison between a propagation loss in each radio resource measured by the measurement unit and a preset threshold;
The radio base station according to claim 1. The controller is
After determining the radio resource group to which radio resources are allocated based on the difference information acquired by the difference information acquisition unit for each radio terminal, based on the communication type information acquired by the communication type information acquisition unit And, in the determined radio resource group, control is performed so as to allocate a radio resource having a relatively large or small propagation loss measured by the measurement unit,
The radio base station according to claim 1 or 2. The controller is
After determining the radio resource group to which radio resources are allocated based on the communication type information acquired by the communication type information acquisition unit for each radio terminal, based on the difference information acquired by the difference information acquisition unit And, in the determined radio resource group, control is performed so as to allocate a radio resource having a relatively large or small propagation loss measured by the measurement unit,
The radio base station according to claim 1 or 2. A radio resource allocation method in a radio base station that performs radio communication by allocating different radio resources to a plurality of radio terminals,
Measuring a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
Obtaining difference information of current transmission power with respect to maximum transmission power transmitted from each of the plurality of wireless terminals;
Obtaining communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the measured propagation loss in each radio resource, classify the plurality of radio resources into at least two radio resource groups, and for each of the plurality of radio terminals, the acquired difference information and the Controlling to allocate the radio resource of the corresponding radio resource group based on the acquired communication type information;
A radio resource allocating method comprising: In a wireless communication system in which different wireless resources are allocated to a plurality of wireless terminals by a wireless base station, and wireless communication is performed between the wireless base station and the plurality of wireless terminals,
Each of the plurality of wireless terminals is
A calculation unit that calculates a difference between the current transmission power and the maximum transmission power that can be transmitted by the wireless terminal, and outputs difference information;
A transmission unit for transmitting the difference information output from the calculation unit to the radio base station,
The radio base station is
A measurement unit that measures a propagation loss in the radio resources allocated to the plurality of radio terminals at each predetermined timing; and
A difference information acquisition unit for acquiring difference information of a current transmission power with respect to a maximum transmission power transmitted from each of the plurality of wireless terminals;
A communication type information acquisition unit for acquiring communication type information indicating the communication type of each of the plurality of wireless terminals;
Based on the propagation loss in each radio resource measured by the measurement unit, the plurality of radio resources are classified into at least two radio resource groups, and for each of the plurality of radio terminals, the difference information acquisition unit A control unit that controls to allocate a radio resource of the corresponding radio resource group based on the difference information acquired in step 1 and the communication type information acquired by the communication type information acquisition unit.
A wireless communication system.

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