JP4498941B2 - Radio scheduling apparatus, radio scheduling method, and radio apparatus - Google Patents

Description

  The present invention relates to a mobile communication system, and more particularly, to a radio scheduling apparatus, a radio scheduling method, and a radio apparatus.

  In recent mobile communication business, users are demanding a communication service that realizes an increase in communication data amount and diversification of communication. For example, in addition to conventional voice calls and data communications (e-mail, web page browsing, small-capacity content download), etc., large-capacity video content is distributed in streaming format in real time or in multicast format There is a demand. Conventional mobile communication systems are generally configured to support data communication using packets. However, in order to meet such a wide variety of communication demands, it is necessary to increase the bandwidth of mobile communication systems. In addition to increasing capacity, it is necessary to guarantee QoS (Quality of Service) according to the type of communication. In addition, it is necessary to flexibly deal with not only the type of content but also the diversification of services such as the priority determined from the charging status of the user and the content.

Packet communication in a conventional mobile communication system is “Best Effort” in which QoS is not guaranteed when performing scheduling for assigning access rights in a wireless section to each wireless flow (hereinafter referred to as wireless scheduling), or a derivative technology thereof. Access rights are assigned based on a proportional fairness algorithm or the like (for example, see Non-Patent Documents 1 and 2). These technologies have a basic design guideline of maximizing radio frequency utilization efficiency, and perform radio flow scheduling according to the radio propagation path state of each user. The wireless flow refers to a communication unit in which access to a wireless section occurs.
V. Bharghavan, S. Lu and T. Nandagopal, “Fair Queueing in Wireless Networks: Issues and Approaches,” IEEE Personal Communications, Feb. 1999. M. Jeong, H. Morikawa and T. Aoyama, “A Fair Scheduling Algorithm for Wireless Packet Networks,” IEICE Trans. On Fundamentals. Vol.84, no.7, pp.1624-1635, July 2001.

  However, since the above-described conventional mobile communication system does not guarantee QoS at the time of wireless scheduling, it cannot sufficiently cope with the increase in the amount of communication data and the diversification of contents and services.

  In addition, QoS in wireless packet communication is defined by delay, transmission rate, packet discard rate, etc., but when performing wireless scheduling considering both QoS guarantee and radio frequency utilization efficiency, it is particularly in QoS guarantee. Delay guarantee is an issue. Usually, in order to improve the radio frequency utilization efficiency, the transmission rate is allocated according to the radio propagation path state of each user. However, in order to guarantee the delay, the delay quality of each user regardless of the radio propagation path state. It performs communication control according to the request for. That is, the radio frequency utilization efficiency decreases when delay is guaranteed. As described above, in the conventional radio scheduling technique, there is a trade-off relationship between delay guarantee and radio frequency utilization efficiency, and a technique for realizing both of them has not been established yet.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a radio scheduling apparatus and a radio scheduling method capable of realizing delay guarantee in a radio section and improving radio frequency utilization efficiency. There is to do.

  Another object of the present invention is to provide a radio apparatus provided with the radio scheduling apparatus of the present invention.

  In order to solve the above-described problems, a radio scheduling apparatus according to the present invention inputs flow information having QoS information required by a radio flow in a radio scheduling apparatus that performs scheduling for assigning access rights in radio sections according to radio flows. Flow information input means, wireless state parameter input means for inputting a wireless state parameter representing the state of the wireless propagation path in the wireless section, storage means for storing the access right assignment status, the flow information and the access An urgent level calculating means for calculating an urgent level indicating a degree of urgency when a radio flow acquires a right to access a radio section based on a right allocation status; and one access based on the urgent level The access right is allocated in a long section including a plurality of periods during which the right is valid. Long section selection means for classifying radio flows based on a request for delay quality, and for each period in which the access right is valid from the selected candidates, Short section selection means for selecting a radio flow to which the access right is assigned, and the short section selection means controls selection of the radio flow according to a request for delay quality for each type of radio flow. To do.

  The radio scheduling apparatus according to the present invention is a radio scheduling apparatus that performs scheduling for assigning radio section access rights by radio flow, QoS information input means for inputting QoS information required by the radio flow, and a radio flow provided to the radio flow Priority information input means for inputting priority information; radio condition parameter input means for inputting a radio condition parameter representing a state of a radio propagation path in the radio section; and storage means for storing the access right assignment status; An urgent level calculating means for calculating an urgent level indicating a degree of urgency when a radio flow acquires a right to access a radio section based on the QoS information, the priority information, and the access right allocation status; Based on the urgency level, includes a plurality of periods during which one access right is valid In the section, a candidate for the wireless flow to which the access right is assigned is selected, and a long section selecting means for classifying the wireless flow based on a request for delay quality, and the access right is effective from the selected candidates. Short section selecting means for selecting a radio flow to which the access right is assigned for each period, the short section selecting means selecting the radio flow according to a request for delay quality for each type of radio flow. It is characterized by controlling.

  In the radio scheduling apparatus according to the present invention, the short interval selecting means controls which radio flow is selected according to a fluctuation tendency of a radio propagation path state based on the radio state parameter. To do.

  The radio scheduling apparatus according to the present invention is characterized in that the short section selection means lowers the selection priority for the radio flow whose radio propagation path state tends to be improved.

  In the radio scheduling apparatus according to the present invention, the short interval selecting means controls which radio flow is selected according to the transmission capacity allocation status in the long interval to which the access right is allocated. Features.

In the radio scheduling apparatus according to the present invention, the short section selection means assigns an access right in preference to a radio flow that does not require a delay quality when the transmission capacity is unallocated. To do.

  In the radio scheduling apparatus according to the present invention, the urgency level calculating means is configured to determine a packet of a radio flow based on a packet allowable maximum delay time included in the QoS information and a packet transmission stop duration for the radio section. Is calculated by calculating the degree of remaining time up to the time point when it is necessary to transmit to the wireless section.

  In the radio scheduling apparatus according to the present invention, the long interval selecting means weights the calculation result of the urgency level calculating means based on the radio condition parameter.

  The radio apparatus according to the present invention acquires flow information having QoS information required by a radio flow for each radio flow in a radio apparatus that controls access in the radio section by assigning radio section access rights for each radio flow. Flow information acquisition means, wireless state measurement means for measuring a wireless state parameter representing a state of a wireless propagation path in the wireless section for each wireless propagation path corresponding to a wireless flow, and the flow information and the wireless state parameter. The wireless scheduling apparatus according to claim 1, further comprising: a scheduling for allocating the access right of the wireless section for each wireless flow.

  The wireless apparatus according to the present invention acquires QoS information required for a wireless flow for each wireless flow in a wireless apparatus that controls access in the wireless section by assigning wireless section access rights for each wireless flow. Means, priority information acquisition means for acquiring priority information given to the radio flow for each radio flow, and radio status parameters indicating the status of radio propagation paths in the radio section corresponding to the radio flow 3. The radio according to claim 2, wherein scheduling is performed to allocate access rights in the radio section for each radio flow using radio status measurement means for measuring each path, and the QoS information, the priority information, and the radio status parameters. And a scheduling device.

  A radio scheduling method according to the present invention is a radio scheduling method for performing scheduling for assigning access rights of radio sections for each radio flow, the step of inputting flow information having QoS information required by a radio flow, and the radio section The degree of urgency when a wireless flow acquires a right to access a wireless section based on the process of inputting a wireless state parameter representing the state of the wireless propagation path in FIG. A process of calculating an urgent level to represent, a process of selecting a radio flow candidate to which the access right is assigned in a long section including a plurality of periods in which one access right is valid based on the urgency level, and a delay quality The process of classifying the radio flow based on the request and the selected candidates A short section selection process for selecting a radio flow to which the access right is assigned, and a process for storing the access right assignment status, for each period in which the access right is valid, and in the short section selection process, The selection of the radio flow is controlled according to the request for the delay quality for each radio flow type.

  A radio scheduling method according to the present invention is a radio scheduling method for performing scheduling for assigning access rights in a radio section for each radio flow, a process of inputting QoS information required by the radio flow, and a priority given to the radio flow. The wireless flow is wireless based on the process of inputting the degree information, the process of inputting the wireless state parameter indicating the state of the wireless propagation path in the wireless section, and the QoS information, the priority information, and the access right assignment state. A process of calculating an urgent level indicating a degree of urgency when acquiring a right to access a section, and the access in a long section including a plurality of periods in which one access right is valid based on the urgency level Based on the process of selecting the radio flow candidates to which the right is assigned and the delay quality requirement, And a short section selection process for selecting a radio flow to which the access right is assigned for each period in which the access right is valid from among the selected candidates, and the assignment of the access right. Storing the situation, and in the short section selection process, the selection of the radio flow is controlled according to the request for the delay quality for each radio flow type.

  In the radio scheduling method according to the present invention, in the short section selection process, it is controlled which radio flow is selected according to a variation tendency of a radio propagation path state based on the radio state parameter. To do.

  The radio scheduling method according to the present invention is characterized in that, in the short section selection process, the selection priority is lowered with respect to a radio flow whose radio propagation path state tends to be improved.

  In the radio scheduling method according to the present invention, in the short section selection process, it is controlled which radio flow is selected according to a transmission capacity allocation state in the long section to which the access right is to be allocated. Features.

The radio scheduling method according to the present invention is characterized in that, in the short section selection process, when there is a margin in the unallocated portion of the transmission capacity, an access right is preferentially assigned to a radio flow that does not require delay quality. To do.

  According to the present invention, the radio flow is classified in a long section according to the urgent level and the priority, the radio flow is classified based on the request for the delay quality, and the radio flow type is determined based on the selection result. Separately, by selecting and controlling the radio flow according to the request for the delay quality, the maximum allowable delay time of the packet can be guaranteed and the transmission rate can be improved, and the delay guarantee in the radio section can be realized. The radio frequency utilization efficiency can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a mobile communication system according to an embodiment of the present invention. In FIG. 1, a base station 1 transmits and receives data to and from a mobile terminal 2 by radio. The base station 1 has a packet switching function. The mobile terminal 2 can perform a call or packet communication via the base station 1.

  FIG. 2 is a block diagram showing a configuration of the base station (wireless device) 1 according to the present embodiment. The base station 1 shown in FIG. 2 is a time division duplex (TDD) method, and uses the same radio frequency for transmission and reception to transmit to the mobile terminal 1 and receive from the mobile terminal 2. Perform in time division. Therefore, the radio propagation path in the radio section between the base station 1 and the mobile terminal 2 is the same for transmission and reception. FIG. 2 shows a configuration for performing radio scheduling when transmitting from the base station to the mobile terminal in the TDD base station, and other configurations are omitted.

  In FIG. 2, a transmission buffer 11 is for storing packets of user data received from the network and temporarily storing packets to be transmitted in the wireless section. The transmission buffer 11 distinguishes and stores packets for each wireless flow.

  The radio frame generation unit 12 generates a radio frame transmitted in the radio section. The radio frame generation unit 12 reads a packet of a radio flow instructed from the scheduler 16 from the transmission buffer 11, generates a radio frame storing the read packet, and outputs the radio frame to the radio unit 13.

  The wireless unit 13 wirelessly transmits the wireless frame received from the wireless frame generation unit 12 via the antenna 14. In addition, the radio unit 13 outputs information representing the reception state of the radio signal received via the antenna 14 to the CNR measurement unit 15.

  The CNR measurement unit 15 measures a CNR (Carrier to Noise Ratio) for each mobile terminal 2 based on the information received from the radio unit 13. Since the base station 1 in FIG. 2 is a TDD system, the CNR of the measurement result is effective in both directions of transmission and reception in the radio section. For each mobile terminal 2, the CNR measurement unit 15 measures an instantaneous CNR (instantaneous CNR) and an average CNR obtained by averaging the instantaneous CNR, and outputs these measurement results to the scheduler 16.

  In the present embodiment, CNR is used as a radio condition parameter representing the state of the radio propagation path in the radio section. Further, the CNR measured for a certain mobile terminal represents the state of the radio propagation path corresponding to the radio flow related to the mobile terminal. In a multicarrier system, CNR measurement needs to be performed for each carrier. Similarly, regarding the average CNR, it is necessary to obtain the average CNR for each carrier and the average CNR for all carriers.

  The scheduler 16 receives flow information from the network for each wireless flow. The flow information includes identification information that can identify a wireless flow, QoS information (QoS information) required by the wireless flow, and priority information of the wireless flow. The scheduler 16 performs radio scheduling based on the QoS information and priority information and the CNR information (instantaneous CNR and average CNR) received from the CNR measurement unit 15. Then, based on the scheduling result, for each radio frame, the radio flow generating unit 12 is instructed by outputting the corresponding radio flow identification information for the radio flow for storing the packet.

FIG. 3 is a block diagram showing a configuration of the scheduler (wireless scheduling apparatus) 16 according to the present embodiment.
In FIG. 3, the flow tag generation / update unit 21 generates a flow tag for each radio flow using flow information (QoS information and priority information) and CNR information. Then, the generated flow tag is stored in the flow tag storage unit 22 in association with the corresponding wireless flow identification information. In addition, the flow tag stored in the flow tag storage unit 22 is updated. A flow tag refers to a parameter set related to scheduling related to a radio flow.

  Parameters included in the flow tag include QoS information, priority information, urgency, number of elapsed frames, instantaneous CNR, average CNR, transmission flag, and radio flow type identifier.

  The priority information has a parameter indicating a user class. The user class is provided with a plurality of types of classes according to the priority based on the user at the time of providing the communication service and the charging information of the content. For example, a premium user class having the highest priority and a normal user class having a standard priority.

The QoS information represents the QoS required by the radio flow, and includes a parameter indicating the QoS class and a parameter indicating the flow QoS.
A plurality of types of classes are provided in the QoS class according to the type of communication application. For example, a CBR (fixed bit rate) class for communication applications that require a fixed communication speed, an rt-VBR (real time variable bit rate) class for communication applications that require a variable communication speed, and real-time characteristics Nrt-VBR (non-real-time variable bit rate) class for communication applications where variable communication speed is not required, especially UBR (unspecified bit rate) class for communication applications where communication speed is not required, the smallest ABR (Available Bit Rate) class for communication applications that require only communication speed. The CBR, rt-VBR, nrt-VBR, UBR, and ABR described above are defined by the ATM (Asynchronous Transfer Mode) forum.

  The flow QoS includes the packet transmission rate of the transmitting terminal, the maximum allowable delay time of the packet (maximum packet allowable delay time), and the allowable loss rate of the packet (packet allowable loss rate).

The degree of urgency represents the degree of urgency when the wireless flow acquires the right to access the wireless section. The urgency level (P) of this embodiment is given by a monotonically increasing function. An example of a formula for calculating the degree of urgency (P) is shown in Formula (1). The larger the value P, the more urgent it is required.
P = 1 / (number of frames that can be waited−number of elapsed frames) (1)
However, the number of frames that can be waited for is the number of radio frames corresponding to the maximum period during which it is allowed to continue to stop transmitting packets of the radio flow to the radio section. Specifically, the number of frames that can be waited for is calculated as the number of radio frames corresponding to the maximum allowable packet delay time in the flow QoS described above.
The number of elapsed frames is a parameter in the flow tag, and is the number of radio frames corresponding to a period during which transmission of a packet of the radio flow has been stopped from the previous transmission time to the radio section. The number of elapsed frames is a parameter representing the access right allocation status in the wireless section.
In addition, the urgency in this embodiment is, in other words, the degree of remaining time until the time point when the packet of the wireless flow must be transmitted to the wireless section.

The transmission flag is a flag indicating that the wireless flow is a candidate for a wireless flow to which an access right for a wireless section is assigned in a certain period (a long section described later).
The wireless flow type identifier indicates the wireless flow type. This type will be described later.

  Returning to FIG. 3, the flow tag storage unit 22 stores the wireless flow identification information and the flow tag in association with each other. The flow tag storage unit 22 is accessible from the long section selection unit 23 and the short section selection unit 24 in addition to the flow tag generation / update unit 21 described above.

  The long section selection unit 23 selects, for each predetermined period (long section), wireless flow candidates and types of wireless flow to which the access right of the wireless section is assigned in the next long section. The selection of the radio flow in this long section is performed based on QoS information, urgency, priority information, and average CNR in the flow tag. The long section selection unit 23 sets a transmission flag and a type identifier in the flow tag as the selection result, and then notifies the short section selection unit 24 of the end of the long section selection. The radio flow is classified based on a request for delay quality.

  The long section is preset as a period having a plurality of radio frames. The period of one radio frame is a period in which one access right in the radio section is valid.

  Upon receipt of the notification of the end of the long section selection from the long section selection section 23, the short section selection section 24 actually selects the radio section for each radio frame (short section) from the radio flows with the transmission flag turned on. Select a radio flow to which access rights are assigned. The selection of the radio flow in this short section is performed based on the type of radio flow and the CNR fluctuation value. The result of selecting the wireless flow in the short section is output to the wireless frame generation unit 12 in FIG. As a result, a radio flow for assigning the access right of the radio section for each radio frame in the next long section is notified to the radio frame generation unit 12. Note that the number of radio flows selected by the short section selection unit 24 is determined by the number of radio flows that can be transmitted at the same time in the system to which the present invention is applied.

  Further, the short section selection unit 24 instructs the flow tag generation / update unit 21 to update the flow tag.

Next, with reference to FIGS. 4, 5, and 6, the operation according to the scheduler 16 of FIG. 3 will be described.
4, 5, and 6 are flowcharts showing the operation flow of the scheduler 16 shown in FIG. 3, FIG. 4 shows the overall processing flow, FIG. 5 shows the long section selection processing flow, and FIG. The section selection process flow is shown.

First, with reference to FIG. 4, the operation of the entire radio scheduling according to the present embodiment will be described.
In FIG. 4, first, each part is initialized (step S1). In this initialization, the flow tag generation / update unit 21 generates a flow tag for each wireless flow and stores it in the flow tag storage unit 22. Information input to the scheduler 16 is set as it is in the QoS information, priority information, instantaneous CNR, and average CNR in the flow tag. The number of elapsed frames is set to an initial value “0”. The transmission flag is set to an initial value “off”. Moreover, the value P calculated by the above equation (1) is set as the urgency level. Further, the type identifier is set to type unselected (in this embodiment, for convenience, “type 0” is set).

  Next, the long section sorting unit 23 sorts radio flows in the long section, and notifies the short section sorting unit 24 of the end of the long section sorting (step S2). Details of the long section selection process in step S2 will be described later. In addition, the long section selection part 23 performs the long section selection process of step S2 for every long section.

  Next, the short section selection unit 24 initializes the variable a to “0” (step S3). This variable “a” represents the number of times of selecting a wireless flow in a short section.

  Next, the short section selection unit 24 performs wireless flow selection in the short section, and notifies the wireless frame generation unit 12 of the flow selection result (step S4). As a result, the radio frame generation unit 12 is notified of one radio flow for assigning radio section access rights related to one radio frame in the next long section. Details of the short section selection process in step S4 will be described later. In the multicarrier system, a radio flow is selected for each carrier in step S4.

  Next, the short section selection unit 24 instructs the flow tag generation / update unit 21 to update the short section tag. In response to this instruction, the flow tag generation / update unit 21 uses the newly input instantaneous CNR to write to the flow tag storage unit 22 to update the instantaneous CNR in the flow tag of each wireless flow (step S5). .

  Next, the short section selection unit 24 increments the variable a by 1 (step S6). Next, the variable a is compared with the value of “long interval / short interval” (step S7). The value of “long section / short section” represents the number of short section selections performed during one long section, and is a predetermined value. As a result of the comparison, if the variable a does not satisfy the value of “long section / short section” (YES in step S7), the process returns to step S4, and the radio flow in the next short section is selected.

  On the other hand, if the variable a is equal to or greater than the value of “long section / short section” (NO in step S7), the process proceeds to step S8, and the short section selection unit 24 updates the long section tag to the flow tag generation / update unit 21. Instruct. In response to this instruction, the flow tag generation / update unit 21 uses the newly input average CNR and instantaneous CNR to write to the flow tag storage unit 22 to update the average CNR and instantaneous CNR in the flow tag of each wireless flow. Do it. Further, regarding the wireless flow in which the transmission flag remains on, writing to the flow tag storage unit 22 is performed to update the number of elapsed frames by adding the value of “long section / short section” to the number of elapsed frames in the flow tag. Do it. Further, the urgency level of each radio flow is recalculated by the above equation (1), and writing for updating the urgency level with the value P of the calculation result is performed to the flow tag storage unit 22. Further, all the transmission flags of each wireless flow are turned off, and writing is performed to the flow tag storage unit 22 so that the type identifiers are all untyped “type 0”.

  Next, if the wireless scheduling process is continued (NO in step S9), the process returns to step S2 to further select the wireless flow in the next long section. On the other hand, if the wireless scheduling process is finished (YES in step S9), the process of FIG. 4 is finished.

  Next, the long section selection process in step S2 and the short section selection process in step S4 will be described in detail.

Here, the technical features according to the present invention will be described before a specific description.
In the present invention, it is an object to realize both the delay guarantee in the radio section and the improvement of the radio frequency utilization efficiency. However, when considering the way of the delay guarantee, the minimum of the average value of the delay time as in the past is considered. It is more important to aim at completion of communication by the use timing of the application that actually uses the communication data, rather than aiming to make it easier. That is, there is virtually no problem as long as packet transmission is completed within the time range of the maximum delay amount allowed by the application. Based on such knowledge, in the present invention, the purpose of the delay guarantee is to guarantee the maximum allowable delay time of the packet, and within the range satisfying this delay guarantee condition, that is, the maximum allowable delay time of the packet. By ensuring the higher transmission rate by allocating radio section access rights to radio flows when the radio propagation path condition is within the range and the radio channel condition is the best, the delay guarantee in the radio section is realized and the radio frequency utilization efficiency To improve.

  First, the long section selection process in step S2 described above will be described with reference to FIG.

In the long section selection process, the above-described wireless flow type classification is performed. In this embodiment, the following three types (for convenience, “type 1”, “type 2”, and “type 3”) are defined. .
Type 1: There is a request for delay quality and it should be transmitted in the next long interval.
Type 2: There is a requirement for delay quality and it is not necessary to transmit in the next long interval.
Type 3: No requirement for delay quality.

  Examples of requirements for delay quality include CBR class and rt-VBR class. Examples of those that do not have a requirement for delay quality include an nrt-VBR class, an ABR class, and a UBR class.

  In the long section selection process according to the present embodiment, the wireless flow is classified into any of the above types 1, 2, and 3. For the “type 1” and “type 3” wireless flows, the transmission flag is turned on. The transmission flag of the “type 2” wireless flow is off. The reason for turning on the transmission flag for the “type 3” radio flow is that “type 3” is transmitted when it can be transmitted because there is no requirement for delay quality, and therefore, whenever there is an opportunity for transmission, transmission is possible. This is to allow it.

  In FIG. 5, first, the long section selection unit 23 reads QoS information of one radio flow from the flow tag storage unit 22 (step S101), and determines whether there is a request for delay quality (step S102). As a result, when there is no delay quality request, the type identifier of the radio flow is set to “type 3”, and the transmission flag is turned on (step S103). On the other hand, if there is a delay quality request, the process proceeds to step S104. At this time, the identification information of the wireless flow with a delay quality requirement is held.

  Next, in step S104, it is determined whether or not the sorting related to Type 3 for all the wireless flows has been completed. If the sorting has not been completed, the process returns to step S101 to perform the sorting related to the next wireless flow. On the other hand, if the sorting is completed, the process proceeds to step S105.

  Next, in step S105, it is determined whether or not there is a wireless flow with a delay quality request. If there is, the process proceeds to step S106. On the other hand, when it does not exist, the long section selection process is terminated.

  Next, in step S106, the urgency level of all radio flows with a delay quality request is read from the flow tag storage unit 22. Next, the wireless flows are ranked based on the urgency (step S107). In this ranking, the radio flows are ranked in order from the one with the highest urgency.

  In the ranking of radio flows, the ranking result based on the degree of urgency may be weighted by priority or average CNR. As an example of weighting by priority, the priority of the premium user and the normal user is set to PrP and PrN, respectively, and the values are added to the ranking result based on the urgent level to perform ranking again. As an example of weighting by average CNR, 1 is added to the result of ranking by urgency when the average CNR is equal to or greater than a value (for example, a predetermined CNR value) that can ensure a constant communication speed, while ensuring If it is not possible, 0 is added and ranking is performed again. In addition, for example, radio flows having the same ranking result according to the degree of urgency may be further ranked in order of higher order simply from the one having a good average CNR.

  Next, the order of one radio flow is compared with the condition (minimum order) of the maximum number of radio flows that can be transmitted in the long interval (step S108). As a result, if the transmission order is within the long section, the type identifier of the wireless flow is set to “type 1”, and the transmission flag is turned on (step S110). On the other hand, if it is not the order in which transmission is possible within the long section, the type identifier of the wireless flow is set to “type 2”, and the transmission flag is turned off (step S111).

  Next, it is determined whether or not the sorting related to the type 1/2 for all wireless flows with delay quality requirements has been completed (step S112). If the sorting has not been completed, the process returns to step S108 and proceeds to the next wireless flow. Perform such sorting. On the other hand, in the case of completion of sorting, the long section sorting process is finished.

  Next, the short section selection process of step S4 described above will be described with reference to FIG.

  In the short section selection process, the radio flow selected by the above long section is scheduled. At that time, the improvement of the radio frequency utilization efficiency is enhanced by taking into account how the wireless propagation path state changes every moment. . Specifically, for radio flows of users whose radio propagation path conditions tend to improve, it is highly possible that the radio propagation path conditions will improve over time and a higher transmission rate can be obtained. Schedule later. On the other hand, for radio flows of users whose radio channel conditions tend to deteriorate, the radio channel conditions may deteriorate over time, leading to a decrease in transmission rate. To do. Thereby, a higher transmission rate can be obtained and it can contribute to the further improvement of radio frequency utilization efficiency.

  In the present embodiment, CNR is used as a radio condition parameter representing the radio propagation path state, and when the CNR is improved, it is determined that the radio propagation path condition tends to be improved, while the CNR is not improved. Sometimes it is determined that the wireless propagation path state does not tend to improve. Specifically, the CNR fluctuation value α is calculated according to the equation (2), and based on the fluctuation value α, it is determined whether or not the CNR is being improved (radio propagation path state improving tendency).

CNR fluctuation value α = latest instantaneous CNR−past instantaneous CNR (2)
However, the past instantaneous CNR used for the calculation of the fluctuation value α is the instantaneous CNR of the past point in time by a predetermined number of radio frames. Further, past instantaneous CNRs corresponding to a predetermined number of radio frames are stored in the flow tag storage unit 22 for each radio flow.

  The fluctuation value α has a positive / negative sign. When the fluctuation value α is a positive value, it is determined that the CNR is improving. When the fluctuation value α is 0 or a negative value, the CNR Judge that it is not improving.

  In FIG. 6, first, the short section selection unit 24 reads the transmission flag of each wireless flow from the flow tag storage unit 22 and searches for a wireless flow whose transmission flag is on (step S201). As a result, if there is a wireless flow whose transmission flag is on, the process proceeds to step S203 (step S202, YES). On the other hand, if there is no wireless flow whose transmission flag is on, the short section selection process is terminated. (Step S202, NO).

  Next, in step S203, the type identifier of each wireless flow is read from the flow tag storage unit 22 to search for a “type 1” wireless flow. As a result, if there is a “type 1” wireless flow, the process proceeds to step S206 (step S204, YES), while if no “type 1” wireless flow exists, the process proceeds to step S205 (step S204, NO).

  In step S205, one wireless flow of “type 3” whose transmission flag is on is selected, and this wireless flow is notified to the wireless frame generation unit 12 as a transmission target flow. Then, the transmission flag of the wireless flow is changed to off. Thereafter, the short section selection process is terminated. As a result, one wireless flow can be transmitted from the “type 3” wireless flows whose transmission flag is on. As a method for selecting one “type 3” wireless flow, for example, there is a method of selecting the one with the maximum instantaneous CNR or performing selection based on a proportional fairness algorithm.

  In step S206, the latest instantaneous CNR and past instantaneous CNR are read from the flow tag storage unit 22 for each “type 1” wireless flow, and the variation value α of the CNR is calculated by the above equation (2).

  Next, the minimum value is searched from these fluctuation values α (step S207). Next, it is determined whether or not the minimum value of the search result is a negative value (step S208). If it is a negative value, the process proceeds to step S209, and if it is not a negative value, the process proceeds to step S210.

  In step S209, a radio flow of “type 1” whose fluctuation value α is minimum (but negative) is notified to the radio frame generation unit 12 as a transmission target flow. Then, the transmission flag of the wireless flow is changed to off and the type identifier is changed to “type 2”. Thereafter, the short section selection process is terminated. As a result, among the “type 1” wireless flows, the wireless flow that can be determined to have the smallest and negative CNR fluctuation value α, that is, the wireless propagation path state is most likely to deteriorate, is transmitted as quickly as possible. Try to get rate.

  In step S210, the transmission request data amounts of all “type 1” wireless flows are summed to obtain the sum of the transmission request data amounts. Next, the sum is compared with the transmission capacity of the remaining period in the long section (step S211). As a result, if the transmission capacity is sufficient, the process proceeds to step S214 (YES in step S212).

  On the other hand, if the transmission capacity is not sufficient, the process proceeds to step S213 (NO in step S212). In step S213, a radio flow of “type 1” whose fluctuation value α is minimum (however, a positive value) is notified to the radio frame generation unit 12 as a transmission target flow. Then, the transmission flag of the wireless flow is changed to off and the type identifier is changed to “type 2”. Thereafter, the short section selection process is terminated. As a result, the transmission of the “type 1” wireless flow is performed first, but among the “type 1” wireless flows, the CNR fluctuation value α is minimum and positive, that is, the radio propagation path state is minimum. Thus, transmission is performed sequentially from the wireless flow that can be determined to be in the network. Therefore, since a radio flow having a greater tendency to improve the radio propagation path state is transmitted later, a large improvement in the radio propagation path state can be expected, which can contribute to obtaining a higher transmission rate.

  In step S214, a search is made for a wireless flow of which the transmission flag is on and “type 3”. As a result, if the transmission flag is ON and there is no “type 3” wireless flow, the process proceeds to step S213 (NO in step S215). On the other hand, if the transmission flag is ON and there is a “type 3” wireless flow, the process proceeds to step S216 (YES in step S215).

  In step S216, as in step S205, the radio flag is selected and one radio flow of “type 3” is selected and notified to the radio frame generation unit 12 as a transmission target flow. To turn off. Thereafter, the short section selection process is terminated. As a result, it is possible to transmit one type of wireless flow of “type 3” and to determine that the state of the wireless propagation path tends to be improved by transmitting the wireless flow of “type 3” first. The flow transmission time can be delayed. Therefore, it can be expected that the radio propagation path state which tends to be improved is improved and a higher transmission rate is obtained.

  The short section selection unit 24 notifies the wireless frame generation unit 12 of the identification information of the wireless flow when the transmission target flow is notified. As a result, the radio flow to be accommodated in the radio frame in the next long section is notified to the radio frame generation unit 12.

As described above, according to the present embodiment, radio scheduling is performed by two-stage selection in which radio flows are selected in a long section, and radio flows are further selected in a short section from the selection result.
In the selection in the long section, QoS guarantee in the wireless section can be achieved by selecting the wireless flow according to the urgency of each wireless flow. Further, by performing weighting based on the average CNR, it is possible to perform control such as ensuring a certain communication speed and performing communication in the wireless section, so that communication throughput in the wireless section can be improved. It becomes possible. Further, by weighting by priority, it is possible to provide a service according to the user's state based on billing information or the like. In addition, the radio flow is classified based on the request for delay quality.

  On the other hand, in the selection in a short section, by selecting the radio flow according to the request for the delay quality for each radio flow type, the maximum allowable delay time of the packet is guaranteed and the transmission rate is improved. be able to.

  Furthermore, it can be expected that a higher transmission rate can be obtained by controlling which radio flow is selected according to the fluctuation tendency of the radio propagation path state based on the dynamic value of the CNR.

  As a result, the delay guarantee guarantees the maximum allowable delay time of the packet, and is within the range satisfying this delay guarantee condition, that is, within the range of the maximum allowable delay time of the packet and has the most radio propagation path state. When good, it is possible to secure a higher transmission rate by assigning a wireless section access right to the wireless flow.

  As described above, according to the mobile communication system according to the present embodiment, it is possible to realize delay guarantee in a radio section and improve radio frequency utilization efficiency.

  In the above-described embodiment, the radio flow selection in the long section is performed based on the urgency level, the priority, and the average CNR. However, the radio flow selection in the long section may be performed based only on the urgency level. Good.

  In the above-described embodiment, the long section selection unit 23 weights the urgency level based on the priority. However, the flow tag generation / update unit 21 preliminarily calculates the urgency level calculation result of the formula (1). Weighting by priority may be performed.

  In the above-described embodiment, FIG. 2 illustrates a configuration in which radio scheduling is performed when transmitting from a base station to a mobile terminal in a TDD base station, but frequency division duplex (FDD) is shown. The present invention can be similarly applied to a system base station. In the case of the FDD scheme, since different radio frequencies are used for transmission and reception, radio propagation paths in the radio section between the base station and the mobile terminal are different for transmission and reception. Therefore, radio scheduling when transmitting from the base station to the mobile terminal requires CNR information (average CNR and instantaneous CNR) measured based on radio signals received by the mobile terminal. For this reason, by providing a means for acquiring CNR information measured by the mobile terminal in the FDD base station, it is possible to perform radio scheduling when transmitting from the base station to the mobile terminal in the FDD base station.

  Also, the scheduler according to the present embodiment can be similarly applied when performing radio scheduling when transmitting from a mobile terminal to a base station. FIG. 7 is a block diagram showing a configuration for performing radio scheduling when transmitting from a mobile terminal to a base station in the base station (wireless apparatus) 1 according to the present embodiment. In FIG. 7, parts corresponding to those in FIG. 2 are given the same reference numerals, and the description thereof is omitted.

  For radio scheduling when transmitting from a mobile terminal to a base station, CNR information (average CNR and instantaneous CNR) measured based on radio signals received by the base station is used. Therefore, the configuration of FIG. 7 is common to both TDD and FDD systems.

In FIG. 7, a flow virtual unit 31 is provided.
In FIG. 7, the flow virtual unit 31 receives the flow transmission request received from the mobile terminal by the receiving unit 13a and the priority information from the network. The flow transmission request includes QoS information of communication performed by the mobile terminal through the wireless section. The flow virtual unit 31 generates flow information of the wireless flow based on the flow transmission request and priority information from the network. This flow information is output to the scheduler 16.

  The CNR measurement unit 15 measures CNR information (average CNR and instantaneous CNR) based on the radio signal received via the antenna 14 by the reception unit 13a. This CNR information is output to the scheduler 16.

  The scheduler 16 executes the radio scheduling process of FIG. 4 using the input flow information and CNR information. A response to the flow transmission request is transmitted via the antenna 14 by the transmission unit 13b to the mobile terminal corresponding to the wireless flow selected by the wireless scheduling process.

  Thereby, the mobile terminal that has received the response to the flow transmission request can obtain the access right in the wireless section and wirelessly transmit. Furthermore, the access rights are assigned so that QoS guarantees and efficient use of radio frequencies can be achieved.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
For example, in the above-described embodiment, the CNR is measured and used for radio scheduling as the radio condition parameter indicating the state of the radio propagation path in the radio section. However, other types of parameters (for example, reception strength and CIR (Carrier to Interference) are used. Ratio) etc.) may be measured and used for radio scheduling.

It is a block diagram which shows the structure of the mobile communication system which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the base station (radio | wireless apparatus) 1 which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the scheduler (radio | wireless scheduling apparatus) 16 which concerns on one Embodiment of this invention. It is a flowchart which shows the whole processing flow of the scheduler 16 shown in FIG. It is a flowchart which shows the long section selection process flow of the scheduler 16 shown in FIG. It is a flowchart which shows the short area selection process flow of the scheduler 16 shown in FIG. It is a block diagram which shows the structure of the base station (radio | wireless apparatus) 1 which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base station (radio | wireless apparatus), 2 ... Mobile terminal, 11 ... Transmission buffer, 12 ... Radio frame production | generation part, 13 ... Radio | wireless part, 13a ... Reception part, 13b ... Transmission part, 14 ... Antenna, 15 ... CNR measurement part , 16 ... scheduler (wireless scheduling apparatus), 21 ... flow tag generation / update unit, 22 ... flow tag storage unit, 23 ... long section selection section, 24 ... short section selection section, 31 ... flow virtual section.

Claims (12)

In a radio scheduling apparatus that performs scheduling for assigning radio section access rights by radio flow,
Flow information input means for inputting flow information having QoS information required by the wireless flow;
A radio condition parameter input means for inputting a radio condition parameter representing a state of a radio propagation path in the radio section;
Storage means for storing the access right assignment status;
Based on the flow information and the access right allocation status, an urgent level calculating means for calculating an urgent level indicating a degree of urgency when a radio flow acquires a right to access a radio section;
Based on the degree of urgency, a radio flow candidate to which the access right is assigned is selected in a long section including a plurality of periods during which one access right is valid, and the radio flow is classified based on a request for delay quality. Long section selection means to perform;
Short-term screening means for selecting a radio flow to which the access right is assigned for each period in which the access right is valid from the selected candidates,
The short interval selection means controls the selection of the radio flow in response to a request for the type separately the delay quality of the radio flow, according to the change trend of the radio state parameter radio channel state based on any of the It is one that controls whether to select a radio flow, radio scheduling apparatus, wherein the radio channel condition lowers the priority of the selected relates to a radio flow in the improved trend. In a radio scheduling apparatus that performs scheduling for assigning radio section access rights by radio flow,
QoS information input means for inputting QoS information required by the wireless flow;
Priority information input means for inputting priority information given to the radio flow;
A radio condition parameter input means for inputting a radio condition parameter representing a state of a radio propagation path in the radio section;
Storage means for storing the access right assignment status;
An urgent level calculating means for calculating an urgent level indicating a degree of urgency when a radio flow acquires a right to access a radio section based on the QoS information, the priority information, and the access right allocation status;
Based on the degree of urgency, a radio flow candidate to which the access right is assigned is selected in a long section including a plurality of periods during which one access right is valid, and the radio flow is classified based on a request for delay quality. Long section selection means to perform;
Short-term screening means for selecting a radio flow to which the access right is assigned for each period in which the access right is valid from the selected candidates,
The short interval selection means controls the selection of the radio flow in response to a request for the type separately the delay quality of the radio flow, according to the change trend of the radio state parameter radio channel state based on any of the It is one that controls whether to select a radio flow, radio scheduling apparatus, wherein the radio channel condition lowers the priority of the selected relates to a radio flow in the improved trend. The short-term selection means in accordance with the allocation status of the transmission capacity in the long-term allocation target of the access right, according to claim 1 or 2, characterized in that control whether to select one of the radio flow Wireless scheduling device. 4. The radio scheduling apparatus according to claim 3 , wherein the short section selection means assigns an access right by giving priority to a radio flow that does not require a delay quality when the transmission capacity is unallocated. .   The urgent level calculation means is a time point when a packet of a radio flow must be transmitted to a radio section based on a maximum allowable packet delay time included in the QoS information and a transmission stop duration of the packet to the radio section. The radio scheduling apparatus according to claim 1, wherein the degree of remaining time until is calculated.   The radio scheduling apparatus according to claim 1, wherein the long section selection unit weights the calculation result of the urgency level calculation unit based on the radio condition parameter. In a wireless device that controls access in the wireless section by assigning access rights in the wireless section for each wireless flow,
Flow information acquisition means for acquiring flow information having QoS information required by the wireless flow for each wireless flow;
A wireless state measuring means for measuring a wireless state parameter representing a state of a wireless propagation path in the wireless section for each wireless propagation path corresponding to a wireless flow;
The radio scheduling apparatus according to claim 1, wherein scheduling is performed to allocate an access right of the radio section for each radio flow using the flow information and the radio state parameter.
A wireless device comprising: In a wireless device that controls access in the wireless section by assigning access rights in the wireless section for each wireless flow,
QoS information acquisition means for acquiring QoS information required by the wireless flow for each wireless flow;
For each wireless flow, priority information acquisition means for acquiring priority information given to the wireless flow;
A wireless state measuring means for measuring a wireless state parameter representing a state of a wireless propagation path in the wireless section for each wireless propagation path corresponding to a wireless flow;
The radio scheduling apparatus according to claim 2, wherein scheduling is performed to allocate access rights of the radio section by radio flow using the QoS information, the priority information, and the radio condition parameter.
A wireless device comprising: A radio scheduling method for performing scheduling for assigning access rights of radio sections according to radio flows,
Inputting flow information having QoS information required by the radio flow;
Inputting a radio condition parameter representing a state of a radio propagation path in the radio section;
A step of calculating an urgency level representing an urgency level when a radio flow acquires a right to access a radio section based on the flow information and the access right allocation status;
Based on the urgency, selecting a radio flow candidate to which the access right is assigned in a long section including a plurality of periods during which the one access right is valid;
The process of categorizing radio flows based on delay quality requirements;
From the selected candidates, for each period in which the access right is valid, a short section selection process of selecting a radio flow to which the access right is assigned;
Storing the assignment status of the access right,
In the above short interval selection process, controls the selection of the radio flow in response to a request for the type separately the delay quality of the radio flow, according to the change trend of the radio state radio channel state based on the parameters, either A radio scheduling method for controlling whether to select a radio flow , wherein the priority of selection is lowered for a radio flow whose radio propagation path state tends to be improved. A radio scheduling method for performing scheduling for assigning access rights of radio sections according to radio flows,
A process of inputting QoS information required by the radio flow;
Entering the priority information given to the radio flow;
Inputting a radio condition parameter representing a state of a radio propagation path in the radio section;
Calculating a degree of urgency representing a degree of urgency when a wireless flow obtains a right to access a wireless section based on the QoS information, the priority information, and the access right assignment state;
Based on the urgency, selecting a radio flow candidate to which the access right is assigned in a long section including a plurality of periods during which the one access right is valid;
The process of categorizing radio flows based on delay quality requirements;
From the selected candidates, for each period in which the access right is valid, a short section selection process of selecting a radio flow to which the access right is assigned;
Storing the assignment status of the access right,
In the above short interval selection process, controls the selection of the radio flow in response to a request for the type separately the delay quality of the radio flow, according to the change trend of the radio state radio channel state based on the parameters, either A radio scheduling method for controlling whether to select a radio flow , wherein the priority of selection is lowered for a radio flow whose radio propagation path state tends to be improved. In the short section selection process,
The radio scheduling method according to claim 9 or 10 , wherein which radio flow is to be selected is controlled according to a transmission capacity allocation status in a long section to which the access right is to be allocated. In the short section selection process,
12. The radio scheduling method according to claim 11 , wherein when there is a margin in the unallocated transmission capacity, an access right is assigned with priority on a radio flow that does not require a delay quality .

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