JP2013098641A - Radio resource allocation apparatus, base station, and radio resource allocation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more reliably start semi-persistent scheduling on a VoIP packet by improving accuracy of recognition of the VoIP packet, in an uplink.SOLUTION: A radio resource allocation apparatus comprises: a BSR management unit 11 for holding BSR information expressing the size of transmission waiting data in a sub frame in a terminal station; a VoIP packet receiving situation management unit 12 which holds the reception data amount of VoIP traffic; a scheduling determination unit 13 which determines whether to perform the semi-persistent scheduling using the BSR information and the reception data amount of VoIP traffic; and a radio packet scheduling unit 14 for allocating radio resources to the terminal station using the determination result of the scheduling determination unit 13 and the BSR information.

Description

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

  In recent years, for example, “LTE (Long Term Evolution)”, which is one of the standards of 3GPP (Third Generation Partnership Project), is known as a next-generation mobile communication system that realizes high-speed and broadband wireless transmission (for example, Non-patent documents 1 and 2). In LTE, an orthogonal frequency division multiple access (OFDMA) system is used as a downlink (link from a base station to a terminal station), and an uplink (link from a terminal station to a base station) is used. A single carrier frequency division multiple access (SC-FDMA) system is used as the multiple access system. The OFDMA scheme is one of multicarrier transmission schemes in which communication is performed using a wideband signal composed of a plurality of subcarriers whose frequencies are orthogonal to each other, and by using different subcarriers for each user (terminal station). , Multiple access between a base station and a plurality of terminal stations is realized. On the other hand, the SC-FDMA system realizes multiple access between one base station and a plurality of terminal stations by spreading the transmission data of each terminal station on frequency axes orthogonal to each other between the terminal stations. To do. Regardless of the uplink or downlink method, LTE defines a time length of 1 ms as a subframe, and the base station allocates radio resources to terminal stations for each subframe. It is a radio resource allocation device in the base station that allocates radio resources in units of subframes.

In LTE, a mechanism for efficiently transmitting VoIP (Voice over IP) traffic is defined in a standard specification. This is called “semi-persistent scheduling”, and is realized by the following procedure by taking advantage of the characteristics of VoIP traffic that arrives periodically.
(A) The base station activates the semi-persistent scheduling through RRC (Radio Resource Control) layer signaling and notifies the terminal station of the packet transmission period in the semi-persistent scheduling.
(A) The base station notifies the first semi-persistent scheduling subframe, resource block (RB), and MCS (Modulation and Coding Scheme) by a control signal in the physical (PHY) layer.
(C) Thereafter, the base station uses the packet transmission period, subframe, and resource block in the subframe specified in (a) (b) without transmitting a control signal in the physical layer, VoIP traffic packet transmission is performed with the terminal station.

  The advantage of this procedure is that, in (c), the base station does not need to transmit a control signal in the physical layer, and therefore can accommodate a lot of VoIP traffic without squeezing the control channel of the physical layer .

  It is known that VoIP traffic is generally characterized by two time zones, a speech period (talk spurt) and a silent period (silence) (see, for example, Non-Patent Document 3). In the time zone of the sound section, the voice is encoded into a packet of about 40 bytes (hereinafter referred to as a VoIP packet) in units of 20 ms (that is, the voice encoding frame length is 20 ms). On the other hand, in the time zone of the silent section, a SID (Silence Insertion Descriptor) packet of about 20 bytes representing the silent state is periodically generated (for example, 160 ms cycle). VoIP traffic is composed of VoIP packets and SID packets.

  Patent Documents 1 and 2 disclose a technique for applying semi-persistent scheduling to a packet (VoIP packet) in a voice section of VoIP traffic. For example, in Patent Document 1, the size of a packet generated from an upper layer (VoIP application) is examined, and if this size is smaller than a reference value, it is set as an SID packet, while if it is larger than the reference value, semi-persistent scheduling is applied as a VoIP packet. ing.

  In the uplink of LTE, the size of data waiting for transmission existing in the transmission buffer of the terminal station can be known from a buffer status report (BSR) sent from the terminal station to the base station. The conventional radio resource allocating device determines that the packet is a VoIP packet if the transmission waiting data size known from the BSR from the terminal station is larger than the reference value, and performs semi-persistent scheduling. Note that, in the uplink of LTE, each traffic belongs to one of four groups (Logical Channel Group: LCG), and the terminal station notifies the base station of the transmission waiting data size by BSR in units of LCG.

  FIG. 3 is a sequence diagram showing a conventional semi-persistent scheduling activation procedure. First, when a packet is generated, the terminal station transmits a scheduling request to the base station (S101). Upon receiving the scheduling request, the base station allocates radio resources by dynamic scheduling in order to cause the terminal station to transmit the BSR (S102). The terminal station transmits the BSR using the allocated radio resource (S103).

  If the received BSR information (transmission waiting data size) is larger than the reference value, the base station assigns radio resources to the terminal station by semi-persistent scheduling, assuming that the transmission waiting data is a VoIP packet (S104).

  The terminal station transmits a VoIP packet using the radio resource allocated by semi-persistent scheduling (S105). The radio resource allocated by the semi-persistent scheduling is a radio resource that can be used by the terminal station to transmit the VoIP packet at a predetermined period (for example, 20 ms period). Accordingly, the terminal station periodically transmits newly generated VoIP packets using the same radio resource in the period.

Special table 2010-534997 gazette JP 2011-66639 A

3GPP TS 36.211, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation” 3GPP TS 36.213, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures” 3GPP TS 26.101, “AMR speech codec frame structure”

  However, if the transmission-waiting data size notified from the terminal station by BSR is simply used as the packet size, there is an inconvenient event. An example of this inconvenient event is shown in FIG. First, when a packet is generated, the terminal station transmits a scheduling request to the base station (S101). When receiving the scheduling request, the base station allocates radio resources by dynamic scheduling in order to cause the terminal station to transmit the BSR (S102).

  Here, the terminal station transmits the BSR using the assigned radio resource. For example, when there is a margin in the radio resource, the terminal station can also transmit the transmission waiting data together with the BSR (S103a). When the terminal station transmits the transmission waiting data together with the BSR, the terminal station transmits the size of the transmission waiting data remaining in the transmission buffer of the terminal station as information on the BSR. For example, when a part of the VoIP packet is transmitted together with the BSR, the BSR information is the size of the remaining data of the VoIP packet remaining in the transmission buffer. Alternatively, when the entire VoIP packet is transmitted together with the BSR, the transmission buffer becomes empty, and the BSR information becomes 0. Then, since the BSR information (transmission waiting data size) is smaller than the size of the VoIP packet, the radio resource allocation device overlooks that the packet transmitted from the terminal station is a VoIP packet and does not activate semi-persistent scheduling. there is a possibility.

  An example of another inconvenient event is shown in FIG. In FIG. 5, a VoIP packet is generated in a state where there is still data waiting to be transmitted (including a packet other than VoIP traffic) in the transmission buffer. In this case, depending on the setting of the terminal station and the status of the data waiting to be transmitted, even if a VoIP packet is generated, a scheduling request or BSR transmission is not performed immediately, and based on the information of the BSR before the VoIP packet is generated. Scheduling has been continued. Thereafter, when the BSR transmission condition is met, the BSR is transmitted. However, if part or all of the VoIP packet has already been transmitted by dynamic scheduling at the time of this BSR transmission, as in the case of FIG. The assigning device may not activate semi-persistent scheduling.

  The present invention has been made in view of such circumstances, and by improving the accuracy of recognizing the occurrence of VoIP packets in the uplink, it is possible to more reliably activate semi-persistent scheduling for VoIP packets. An object of the present invention is to provide a radio resource allocation device, a base station, and a radio resource allocation method.

  In order to solve the above problems, a radio resource allocation device according to the present invention allocates uplink radio resources to a terminal station that transmits traffic that periodically generates packets having a fixed data length. In the allocating device, a transmission waiting data size management unit that holds information indicating a transmission waiting data size that is an amount of data of the traffic that is waiting for transmission in a certain subframe in the terminal station, and a base station that transmits the terminal station A traffic reception status management unit that holds the received data amount of the traffic received from the information, information on a transmission waiting data size held by the transmission waiting data size management unit, and a received data amount held by the traffic reception status management unit, To determine whether to perform semi-persistent scheduling for the terminal station A scheduling determination unit, a determination result of the scheduling determination unit, and a radio packet scheduling unit that performs radio resource allocation to the terminal station using information on a transmission waiting data size held by the transmission waiting data size management unit; It is provided with.

  In the radio resource allocation device according to the present invention, the scheduling determination unit adds the transmission waiting data size of a certain subframe related to the terminal station and the received data amount of the traffic in the subframe related to the terminal station. The evaluation value is calculated, the evaluation value is compared with a reference value, and the determination is performed based on the comparison result.

  In the radio resource allocating device according to the present invention, the scheduling determination unit includes the difference in the transmission-waiting data size between certain subframes related to the terminal station and the received data of the traffic between the subframes related to the terminal station. An evaluation value based on the sum with the quantity is calculated, the evaluation value is compared with a reference value, and the determination is performed based on the comparison result.

  A radio resource allocating device according to the present invention is a radio resource allocating device that allocates uplink radio resources to a terminal station that transmits traffic that periodically generates a packet having a fixed data length. A transmission waiting data size management unit that holds information indicating a transmission waiting data size that is the amount of traffic data waiting to be transmitted in a subframe, and a received data amount of the traffic received by the base station from the terminal station And an evaluation value based on the received traffic amount of the traffic between subframes related to the terminal station, using the received traffic amount held by the received traffic status management unit and the received traffic amount management unit. The evaluation value is compared with the reference value, and based on the comparison result, the terminal station Wireless communication for the terminal station using a scheduling determination unit that determines whether or not to perform the scheduling, a determination result of the scheduling determination unit, and information on a transmission waiting data size held by the transmission waiting data size management unit And a radio packet scheduling unit that performs resource allocation.

  A base station according to the present invention includes any one of the radio resource allocation apparatuses described above, and performs uplink radio resource allocation to a terminal station.

  A radio resource allocation method according to the present invention is a radio resource allocation method for allocating uplink radio resources to a terminal station that transmits traffic that periodically generates packets having a fixed data length, the terminal station comprising: A transmission waiting data size management step for holding information indicating a transmission waiting data size that is the amount of traffic data waiting to be transmitted in a certain subframe, and reception of the traffic received by the base station from the terminal station. Using the traffic reception status management step for holding the data amount, the information on the transmission wait data size held in the transmission wait data size management step, and the reception data amount held in the traffic reception status management step, Determine whether to perform semi-persistent scheduling for terminal stations A radio packet scheduling step for performing radio resource allocation to the terminal station using a scheduling determination step, a determination result of the scheduling determination step, and information on a transmission wait data size held in the transmission wait data size management step; , Including.

  A radio resource allocation method according to the present invention is a radio resource allocation method for allocating uplink radio resources to a terminal station that transmits traffic that periodically generates packets having a fixed data length, the terminal station comprising: A transmission waiting data size management step for holding information indicating a transmission waiting data size that is the amount of traffic data waiting to be transmitted in a certain subframe, and reception of the traffic received by the base station from the terminal station. A traffic reception status management step for holding a data amount, and an evaluation value based on the traffic reception data amount between certain subframes related to the terminal station, using the received data amount held in the traffic reception status management step And comparing the evaluation value with a reference value, and based on the comparison result, the terminal station Using a scheduling determination step for determining whether or not to perform semi-persistent scheduling, a determination result of the scheduling determination step, and information on the transmission waiting data size held in the transmission waiting data size management step, And a radio packet scheduling unit for allocating radio resources to the terminal station.

  ADVANTAGE OF THE INVENTION According to this invention, the precision which recognizes generation | occurrence | production of a VoIP packet in an uplink can be improved. Thereby, the effect that the semipersistent scheduling with respect to a VoIP packet can be started more reliably is acquired.

It is a schematic block diagram of the radio | wireless communications system which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless resource allocation apparatus 10 shown in FIG. It is a sequence diagram which shows the conventional semipersistent scheduling starting procedure. It is a sequence diagram for demonstrating the subject of the conventional semipersistent scheduling starting procedure. It is a sequence diagram for demonstrating the subject of the conventional semipersistent scheduling starting procedure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a radio communication system according to an embodiment of the present invention. In FIG. 1, the base station 1 includes a radio resource allocation device 10. The terminal station 2a communicates with the base station 1 by wireless connection. The base station 1 and the terminal station 2a use LTE as a communication standard. The base station 1 is connected to the network and can communicate with the terminal station 2b via the network. The terminal station 2a and the terminal station 2b perform voice communication using VoIP.

  FIG. 2 is a block diagram showing a configuration of the radio resource allocation device 10 shown in FIG. In FIG. 2, the radio resource allocation device 10 includes a BSR management unit 11, a VoIP packet reception status management unit 12, a scheduling determination unit 13, and a radio packet scheduling unit 14.

  The received packet demodulator 20 of the base station 1 demodulates the packet received from the terminal station 2a. The demodulated packet is sent to the upper layer via the reception packet buffering unit 30.

  The BSR manager 11 acquires the BSR from the packet demodulated by the received packet demodulator 20. The BSR is sent to the base station 1 after being irregularly placed on a packet transmitted from the terminal station 2a. The BSR is information indicating the amount of data (transmission wait data) that is waiting for transmission in the terminal station 2a (transmission wait data size). The BSR management unit 11 records the BSR and the subframe number (subframe ID) that received the BSR in association with each other.

  The VoIP packet reception status management unit 12 measures the received data amount of the LCG to which the VoIP traffic belongs among the packets demodulated by the received packet demodulation unit 20. The VoIP packet reception status management unit 12 records the received data amount of the measurement result and the subframe ID of the measured subframe in association with each other.

  The scheduling determination unit 13 uses the BSR of the LCG to which the VoIP traffic belongs among the BSRs recorded by the BSR management unit 11 and the received data amount recorded by the VoIP packet reception status management unit 12 to perform semi-parity. It is determined whether or not to perform constant scheduling.

  The radio packet scheduling unit 14 allocates radio resources to the terminal station 2a using the determination result of the scheduling determination unit 13 and the BSR recorded by the BSR management unit 11. This radio resource allocation result is output as a scheduling result.

  Next, the semi-persistent scheduling determination process performed by the scheduling determination unit 13 illustrated in FIG. 2 will be described with reference to an example. In the following embodiment, the LCG to which the VoIP traffic belongs is the l-th LCG.

When the scheduling determination unit 13 detects that the BSR of the l-th LCG is included in the packet received in the i-th subframe from the terminal station 2a (u), the scheduling determination unit 13 calculates the evaluation value D by the following equation.
D = Best (u, i, l) + g (u, i, l)
However, Best (u, i, l) is the transmission waiting data size in the i-th subframe of the terminal station 2a (u), which is represented by the BSR of the l-th LCG. g (u, i, l) is the data amount of the received data of the l-th LCG among the received data of the i-th sub-frame from the terminal station 2a (u).

  The scheduling determination unit 13 acquires Best (u, i, l) from the BSR management unit 11. The scheduling determination unit 13 acquires g (u, i, l) from the VoIP packet reception status management unit 12.

  Next, the scheduling determination unit 13 compares the evaluation value D with a predetermined reference value P. As a result, when the evaluation value D is larger than the reference value P, the scheduling determination unit 13 instructs the radio packet scheduling unit 14 to perform semi-persistent scheduling of the terminal station 2a (u).

  On the other hand, when the evaluation value D is equal to or less than the reference value P, the scheduling determination unit 13 does not instruct the radio packet scheduling unit 14 in particular. In this case, the radio packet scheduling unit 14 performs dynamic scheduling for G on the terminal station 2a (u).

  The radio packet scheduling unit 14 determines the resource block and MCS to be allocated to the terminal station 2a (u) by semi-persistent scheduling so that the predetermined VoIP packet size is sufficient.

  When the scheduling determination unit 13 detects that the BSR of the l-th LCG is included in the packet received in the i-th subframe from the terminal station 2a (u), the scheduling determination unit 13 calculates the evaluation value D by the following equation.

  However, Best (u, x, l) is the transmission waiting data size in the x-th subframe of the terminal station 2a (u) represented by the BSR of the l-th LCG. i 'is the subframe ID of the previous BSR reception of the l-th LCG of the terminal station 2a (u). g (u, j, l) is the data amount of the received data of the lth LCG among the received data of the jth subframe from the terminal station 2a (u). d is the frame length of the voice encoding of the VoIP packet.

  The scheduling determination unit 13 acquires Best (u, i, l) and Best (u, i ′, l) from the BSR management unit 11. The scheduling determination unit 13 acquires g (u, j, l) from the VoIP packet reception status management unit 12 (where j is from “i ′ + 1” to i).

  Next, the scheduling determination unit 13 compares the evaluation value D with a predetermined reference value P. As a result, when the evaluation value D is larger than the reference value P, the scheduling determination unit 13 instructs the radio packet scheduling unit 14 to perform semi-persistent scheduling of the terminal station 2a (u).

  On the other hand, when the evaluation value D is equal to or less than the reference value P, the scheduling determination unit 13 does not instruct the radio packet scheduling unit 14 in particular. In this case, the radio packet scheduling unit 14 performs dynamic scheduling for G on the terminal station 2a (u).

  The radio packet scheduling unit 14 determines the resource block and MCS to be allocated to the terminal station 2a (u) by semi-persistent scheduling so that the predetermined VoIP packet size is sufficient.

  The scheduling determination unit 13 calculates the evaluation value D for each terminal frame with respect to the terminal station 2a (u) by the following equation.

  However, i is the latest received subframe ID of the terminal station 2a (u). g (u, j, l) is the data amount of the received data of the lth LCG among the received data of the jth subframe from the terminal station 2a (u). d is the frame length of the voice encoding of the VoIP packet. d 'is a predetermined time length. d 'is determined in advance as an arbitrary time length.

  The scheduling determination unit 13 acquires g (u, j, l) from the VoIP packet reception status management unit 12 (where j is from “i-d ′ + 1” to i).

  Next, the scheduling determination unit 13 compares the evaluation value D with a predetermined reference value P. As a result, when the evaluation value D is larger than the reference value P, the scheduling determination unit 13 instructs the radio packet scheduling unit 14 to perform semi-persistent scheduling of the terminal station 2a (u).

  On the other hand, when the evaluation value D is equal to or less than the reference value P, the scheduling determination unit 13 does not instruct the radio packet scheduling unit 14 in particular. In this case, the radio packet scheduling unit 14 performs dynamic scheduling for G on the terminal station 2a (u).

  The radio packet scheduling unit 14 determines the resource block and MCS to be allocated to the terminal station 2a (u) by semi-persistent scheduling so that the predetermined VoIP packet size is sufficient.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, the VoIP packet of the VoIP traffic is targeted as the traffic to which the semi-persistent scheduling is applied, but is not limited to this. Semi-persistent scheduling can be applied to traffic that periodically generates a packet having a fixed data length.

DESCRIPTION OF SYMBOLS 1 ... Base station, 2a ... Terminal station, 10 ... Radio | wireless resource allocation apparatus, 11 ... BSR management part, 12 ... VoIP packet reception condition management part, 13 ... Scheduling determination part, 14 ... Wireless packet scheduling part

Claims (7)

In a radio resource allocation apparatus that allocates uplink radio resources to a terminal station that transmits traffic that periodically generates packets having a fixed data length,
A transmission waiting data size management unit for holding information indicating a transmission waiting data size that is an amount of data of the traffic waiting to be transmitted in a certain subframe in the terminal station;
A traffic reception status management unit that holds a received data amount of the traffic received by the base station from the terminal station;
Whether or not to perform semi-persistent scheduling for the terminal station using information on the transmission wait data size held by the transmission wait data size management unit and the received data amount held by the traffic reception status management unit A scheduling determination unit for determining
A radio packet scheduling unit that performs radio resource allocation to the terminal station using a determination result of the scheduling determination unit and information on a transmission wait data size held by the transmission wait data size management unit;
A radio resource allocation device comprising: The scheduling determination unit calculates an evaluation value obtained by adding the transmission waiting data size of a certain subframe related to the terminal station and the received data amount of the traffic in the subframe related to the terminal station. And the reference value are compared, and the determination is performed based on the comparison result.
The radio resource allocating device according to claim 1. The scheduling determination unit includes:
An evaluation value is calculated based on a sum of a difference in the transmission waiting data size between certain subframes related to the terminal station and a received data amount of the traffic between the subframes related to the terminal station, and the evaluation value And the reference value are compared, and the determination is performed based on the comparison result.
The radio resource allocating device according to claim 1. In a radio resource allocation apparatus that allocates uplink radio resources to a terminal station that transmits traffic that periodically generates packets having a fixed data length,
A transmission waiting data size management unit for holding information indicating a transmission waiting data size that is an amount of data of the traffic waiting to be transmitted in a certain subframe in the terminal station;
A traffic reception status management unit that holds a received data amount of the traffic received by the base station from the terminal station;
Using the received data amount held by the traffic reception status management unit, an evaluation value based on the received data amount of the traffic between subframes related to the terminal station is calculated, and the evaluation value is compared with a reference value. A scheduling determination unit that determines whether to perform semi-persistent scheduling for the terminal station based on the comparison result;
A radio packet scheduling unit that performs radio resource allocation to the terminal station using a determination result of the scheduling determination unit and information on a transmission wait data size held by the transmission wait data size management unit;
A radio resource allocation device comprising:   A base station comprising the radio resource allocation device according to claim 1, wherein uplink radio resource allocation is performed for a terminal station. A radio resource allocation method for allocating uplink radio resources to a terminal station that transmits traffic that periodically generates a packet having a fixed data length,
A transmission waiting data size management step for holding information indicating a transmission waiting data size that is an amount of data of the traffic waiting to be transmitted in a certain subframe in the terminal station;
A traffic reception status management step for holding a received data amount of the traffic received by the base station from the terminal station;
Whether to perform semi-persistent scheduling for the terminal station using the information on the data size waiting for transmission held in the step of managing data size waiting for transmission and the amount of received data held in the step of managing traffic reception status A scheduling determination step for determining whether or not;
A radio packet scheduling step for allocating radio resources to the terminal station using the determination result of the scheduling determination step and the information of the transmission wait data size held in the transmission wait data size management step;
A radio resource allocating method comprising: A radio resource allocation method for allocating uplink radio resources to a terminal station that transmits traffic that periodically generates a packet having a fixed data length,
A transmission waiting data size management step for holding information indicating a transmission waiting data size that is an amount of data of the traffic waiting to be transmitted in a certain subframe in the terminal station;
A traffic reception status management step for holding a received data amount of the traffic received by the base station from the terminal station;
Using the received data amount held in the traffic reception status management step, an evaluation value based on the received data amount of the traffic between subframes related to the terminal station is calculated, and the evaluation value is compared with a reference value. A scheduling determination step for determining whether to perform semi-persistent scheduling for the terminal station based on the comparison result;
A radio packet scheduling unit that performs radio resource allocation to the terminal station using the determination result of the scheduling determination step and the information of the transmission wait data size held in the transmission wait data size management step;
A radio resource allocating method comprising:

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