JP2008141709A - Communication system, base station, terminal and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart a plurality of service priorities to a flow in one wireless link by assigning a transmission queue to every service in multiservice where one wireless link is shared among a plurality of services. <P>SOLUTION: A communication system 1 performing communication by connecting a base station 2 and a terminal 3 through a single wireless link comprises a communication control means 2-1 performing a plurality of different types of communications using the single wireless link in addition to a type of communications performed at first using the single wireless link by adding a different type of communication. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication system and a base station, a terminal, and a communication method used in the communication system.

  QoS control in a radio section in a mobile communication system such as a digital cellular phone system or a PHS system is realized in a data link layer (MAC layer) in the OSI reference model. Note that QoS (Quality of Service) is a function that guarantees transmission quality by setting a priority (service priority) for each communication on a network.

  When QoS control is to be realized in a radio section in such a mobile communication system, the IP header is removed when downlink (downlink) data arrives at the MAC layer, so the TOS field of the IP header is used. Control is not possible.

  For this reason, service priority negotiation is performed in the process of call connection from the terminal, and QoS control is performed for each communication path.

  In the next-generation mobile communication system, when a multi-service (also referred to as multi-call), which is a plurality of services, is introduced for one user, it is conceivable that services with different service priorities are mixed. For example, VoIP (Voice Over IP) (for example, a service with the highest service priority) and e-mail (for example, a service with the lowest service priority) that convert voice data into IP packets and transmit / receive are mixed. The case is considered.

Patent Document 1 discloses a method for managing a large number of independent simultaneous calls between a mobile communication network and a subscriber terminal.
JP 2005-525934 Gazette

  In the conventional technology such as Patent Document 1 described above, since only one radio link is allowed for one user, different service priorities cannot be mixed, or even if they can be mixed, there is a single There has been a problem that a wireless link cannot have a plurality of service priorities.

  The present invention has been made to solve the above-described problems, and in a multi-service in which one radio link is shared by a plurality of services, a transmission queue is assigned to each service, and a flow in one radio link is performed. It is an object to obtain a communication system, a base station, a terminal, and a communication method thereof.

  In order to solve the above problems, a communication system according to the present invention is a communication system in which a base station and a terminal are connected by a single radio link to perform communication. In addition to the type of communication, a communication control means for adding a type of communication different from the type of communication is provided (claim 1).

  Thus, a plurality of different types of communication can be added using a single wireless link.

  In addition, according to the type, a transmission unit that transmits a service identifier that specifies the type, and a reception unit that receives the service identifier, and the communication control unit, the communication control unit according to the received service identifier A transmission queue for storing communication data is assigned for each type (claim 2).

  Thereby, a transmission queue for storing communication data is assigned for each type of communication corresponding to the service identifier, and communication control corresponding to the type of communication can be performed.

  Further, the communication control means controls the frequency of data transmission to be different for each transmission queue according to the service identifier (claim 3).

  In this way, by performing communication control according to the type of communication so that the frequency of data transmission differs for each transmission queue, until the packet is queued and output according to the communication service The communication data rate can be changed for each communication service.

  Further, the type is a communication application (claim 4).

  Thereby, the effect of the said Claims 1-3 can be acquired with respect to various communication applications.

  In addition, communication is performed according to the OFDMA scheme, and the communication control unit assigns a subchannel, which is a communication channel in the OFDMA scheme, according to the type.

  Thereby, in the communication system in the OFDMA system, a plurality of different types of communication can be performed using a single radio link.

  Further, the communication control means allocates the number of subchannels corresponding to the service identifier for each transmission queue (Claim 6).

  This makes it possible to make a difference in the data rate for each transmission queue corresponding to the communication service.

  Further, the transmission means transmits the service identifier through the subchannel (claim 7).

  As a result, in the communication system in the OFDMA scheme, it is possible to perform transmission of a plurality of different types using a single radio link by transmitting the service identifier included in the subchannel.

  The base station according to the present invention is a base station that communicates with a terminal through a single radio link, and in addition to the type of communication that is initially performed using the single radio link, A transmission queue that stores communication data for each type according to the service identifier, and a communication control unit that adds a communication identifier for the type and a reception unit that receives the service identifier that identifies the type. And the control is performed so that the frequency of data transmission differs for each transmission queue according to the service identifier (claim 8).

  As a result, it is possible to add different types of communication in addition to the communication that was initially performed, and further by making the communication control according to the type different in the frequency of data transmission for each transmission queue, the communication service Accordingly, it is possible to obtain a base station that can be controlled to change the time from when a packet is queued to when it is output.

  Further, the communication is performed by the OFDMA system, and the communication control unit assigns a communication subchannel in the OFDMA system according to the type (claim 9).

  Thereby, in a base station that performs OFDMA communication, it is possible to perform transmission of a service identifier in a subchannel and perform a plurality of different types of communication using a single radio link.

  The terminal according to the present invention is a terminal used in a communication system that adds a different type of communication to the base station and a type of communication initially performed using a single radio link. And a transmission means for transmitting a service identifier for specifying the type of communication. The transmission means transmits the service identifier through a sub-channel that is a communication channel in the OFDMA scheme. Item 10).

  As a result, in a terminal that performs OFDMA communication, a different type of communication is used in addition to the communication that was initially performed using a single radio link by transmitting the service identifier in the subchannel. Can be added.

  The communication method according to the present invention is a communication system that performs communication by connecting a base station and a terminal with a single radio link, in addition to the type of communication that is initially performed using the single radio link, A communication method for adding a communication of a type different from communication, wherein, according to the type, a step of transmitting a service identifier that specifies the type, a step of receiving the service identifier, and the received service identifier Allocating a transmission queue for storing communication data for each of the types corresponding thereto (claim 11).

  In this way, it is possible to add different types of communication in addition to the communication that was initially performed, and further by performing communication control according to the type of communication so that the frequency of data transmission differs for each transmission queue Depending on the communication service, the time from when the packet is queued to when it is output can be changed.

  According to the present invention, in a multi-service in which one radio link is shared by a plurality of services, a transmission queue can be assigned for each service, and a flow in one radio link can have a plurality of service priorities. Communication method, base station, terminal, and communication method thereof.

  First, prior to the description of the communication system according to the present embodiment, the frame structure of OFDMA used in the communication system will be described with reference to the explanatory diagram of FIG.

  FIG. 1 shows, for example, an OFDMA frame configuration when four time slots (S1 to S4) are used in the PHS system, where the vertical axis is the frequency axis and the horizontal axis is the time axis.

  In FIG. 1, both the downlink period and the uplink period are divided into 28 frequency bands with respect to the frequency axis. The subchannel of the first frequency band is called a control subchannel and is used in the control channel (CCH). Note that the first frequency band may be either the highest frequency band or the lowest frequency band. Also, the control subchannel indicates which subchannel of each time slot is used in each frequency band.

  The example of FIG. 1 is an example of a PHS system, and the base stations that can be specified by the control subchannels C1 to C4 are four base stations. In the PHS system, the control channel is intermittently transmitted every 100 ms.

  The remaining 27 frequency bands are composed of traffic subchannels T1 to T108 for transmitting and receiving data, and are composed of 27 subchannels in the frequency direction and 4 in the time axis direction, for a total of 108 subchannels. ing.

  This traffic subchannel includes an anchor subchannel and an extra subchannel.

  An anchor subchannel is used to notify each terminal which subchannel is used by each terminal, and is used to negotiate between the base station and the terminal whether data has been exchanged correctly by retransmission control. It is a subchannel.

  The extra subchannel is a subchannel that transmits data to be actually used, and a plurality of extra subchannels can be assigned to one terminal. In this case, as the number of allocated extra subchannels increases, the bandwidth is widened, so that high-speed communication is possible.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a communication system according to the present invention will be described in detail with reference to the drawings. FIG. 2 is a configuration diagram of a communication system according to the embodiment of the present invention.

  As shown in FIG. 2, the communication system according to the embodiment of the present invention is a communication system 1 in which a base station 2 and a terminal 3 are connected by a single wireless link for communication, and the base station 2 is a network. 4 is connected.

  The base station 2 controls communication of the base station, communication control means 2-1 that performs a plurality of different types of communication using a single radio link, and transmission means 2 that is connected to an antenna and transmits data and voice to the terminal. -2, The receiving means 2-3 which receives the data and audio | voice from a terminal is provided.

  The terminal 3 includes a transmitting unit 2-2 that is connected to an antenna and transmits data and voice to the base station, and a receiving unit 2-3 that receives data and voice from the base station.

  The communication system according to the present embodiment will be described in detail with reference to FIG. 3, which shows an example of a communication procedure sequence between the terminal 2 and the base station 3.

  The sequence in FIG. 3 is an example in the case where the terminal 2 makes a voice call and receives an E-mail during voice communication (call).

(1) When the user performs a voice call transmission operation at the terminal 3, the transmission means 3-1 of the terminal 3 transmits a link channel (LCH) establishment request to the connection destination base station 2.

(2) The communication control means 2-1 of the base station 2 that has received the link channel (LCH) establishment request assigns an anchor subchannel (ASCH) based on carrier sense, and the transmission means 2-2 causes the link channel (LCH) ) Notify the terminal of the anchor subchannel (ASCH) by allocation.

(3) The terminal 3 that has received the link channel (LCH) assignment by the receiving unit 3-2 transmits a service flow addition request to the base station 2 by the transmitting unit 3-1. The service flow addition request includes a service identifier for identifying a service flow to be communicated by the terminal 3 and a service priority requested by the communication application.

  Specifically, a service required for the payload portion is transmitted as a message to the base station using the extra subchannel (ESCH). At this time, the value of the CD field as the service identifier is (0, 0, 0).

(4) The communication control means 2-1 of the base station 2 that has received the service flow addition request sends a transmission queue (transmission queue) that stores communication data corresponding to the type of service for the service flow requested by the terminal 3. 1) is assigned, and the frequency of data transmission is controlled so as to satisfy the service priority requested corresponding to the voice communication as the service type.

  Next, the transmission means 2-2 of the base station 2 transmits a service flow addition confirmation to the terminal, and notifies that the preparation for exchanging data on the base station side is completed.

(5) The terminal 3 that has received the service flow addition confirmation by the reception unit 3-2 transmits a radio bandwidth request to the base station side by the transmission unit 3-1.

(6) The communication control means 2-1 of the base station 2 that has received the wireless bandwidth request secures a wireless bandwidth for the service. In order to notify the secured radio band, the transmission unit 2-2 notifies the terminal of the position of the subchannel used for communication by the MAP, and starts voice communication (call).

  At this time, the frequency of data transmission is controlled so that the transmission queues of both the base station 2 and the terminal 3 satisfy the service priority requested corresponding to the voice communication as the service type.

  The data receiving side identifies a communication application in which the arrived data is to be received, based on the service identifier included in the received data.

(7) When the e-mail arrives at the base station 2 to the user in voice communication, the packet reception is notified by paging, but the base station 2 recognizes that the user who should receive the call is in communication. ing.

  When the base station 2 determines that the terminal 3 that should receive the call is in communication, the paging is not transmitted and the same processing as (4) is performed. In this case, the communication control means 2-1 assigns the service priority assigned to the e-mail service, which is the service type, as the service priority assigned to the transmission queue. Further, a transmission queue (transmission queue 2) different from that notified in (4) is allocated, and the frequency of data transmission is controlled so as to satisfy the service priority requested corresponding to the e-mail service. At this time, the anchor subchannel changes the allocation of the extra subchannel used for data transmission for each service according to the service priority.

  In this way, by connecting the base station 2 and the terminal 3 with a single radio link, passing data allocated with different service identifiers therein, and sharing the single radio link with a plurality of service flows Has realized multi-service.

  Next, a service identifier that identifies the type of communication according to the type of communication will be described. FIG. 4 is a diagram showing the configuration of the MAC frame in the present embodiment.

  The communication system according to the present embodiment is characterized in that the CD field for identifying control information and data in the MAC header portion is extended to a 3-bit area (Bit1, Bit2, Bit3).

  When the value (Bit1, Bit2, Bit3) of the CD field is (0, 0, 0), it indicates that the content of the MAC payload is MAC control data. In other cases, that is, (0, 0, 1) In the case of ~ (1,1,1), this value indicates a service identifier (S1 to S7) used by the user.

  Next, a method for transmitting and receiving service flows having different service identifiers over a single wireless link will be described. FIG. 5 is a table showing an example of a correspondence relationship between communication applications different from service identifiers and weights assigned to service priorities.

  As shown in FIG. 5, the service priorities Priority1 to Priority5 are weighted in advance. That is, the service priority is determined according to the service identifier.

  For example, consider a multi-service using the Priority 1 service (service identifier: S1) and the Priority 5 service (service identifier: S5) in a single wireless link in the table of FIG.

  In this example, when the radio band reserved for data transmission is sufficient to satisfy the quality of both services, the band necessary for the service S1 is reserved for data transmission of the service S1. Are allocated for data transmission of service S5.

  Also, if the radio band reserved for data transmission is not sufficient to satisfy both service qualities, the ratio of the band reserved for service S1 and the band reserved for service S5 is assigned to each priority. It is the ratio of the given weight. In this example, the weight ratio of S1 and S5 is 10: 2, so the bandwidth allocation of S1 and S5 shares the reserved bandwidth at a ratio of 10: 2.

  As a result, it is possible to avoid continually allocating a radio band only to a service having a high service priority.

It is explanatory drawing which shows the frame structure of OFDMA used for the communication method which concerns on embodiment of this invention. 1 is a schematic diagram of a communication system according to an embodiment of the present invention. It is a sequence diagram in the communication system which concerns on embodiment of this invention. It is a figure which shows the structure of the MAC frame in the communication system which concerns on embodiment of this invention. It is a table | surface which shows an example of the weight assigned to the service priority corresponding to a different kind of communication application in the communication system which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 2 Base station 2-1 Communication control means 2-2 Transmission means 2-3 Reception means 3 Terminal 3-1 Transmission means 3-2 Reception means 4 Network

Claims (11)

  In a communication system in which a base station and a terminal are connected by a single radio link for communication, in addition to the type of communication initially performed using the single radio link, a communication of a type different from the communication is performed. A communication system comprising a communication control means to be added. According to the type, a transmission means for transmitting a service identifier for specifying the type;
Receiving means for receiving the service identifier,
The communication system according to claim 1, wherein the communication control unit allocates a transmission queue for storing communication data for each type according to the received service identifier. The communication control means includes
The communication system according to claim 2, wherein control is performed such that the frequency of data transmission differs for each transmission queue in accordance with the service identifier.   The communication system according to claim 1, wherein the type is a communication application. Communicate using the OFDMA method,
The communication system according to any one of claims 1 to 4, wherein the communication control means assigns a subchannel, which is a communication channel in the OFDMA scheme, according to the type.   The communication system according to any one of claims 2 to 5, wherein the communication control unit allocates the number of subchannels corresponding to the service identifier for each transmission queue.   The communication system according to claim 5 or 6, wherein the transmission means transmits the service identifier through the subchannel. In a base station that communicates by connecting to a terminal with a single wireless link
Communication control means for adding, in addition to the type of communication initially performed using the single wireless link, a type of communication different from the communication;
Receiving means for receiving a service identifier specifying the type,
The communication control means allocates a transmission queue for storing communication data for each type according to the service identifier,
A base station that controls the frequency of data transmission to be different for each transmission queue according to the service identifier. Communicate using the OFDMA method,
The base station according to claim 8, wherein the communication control unit allocates a communication subchannel in the OFDMA scheme according to the type. In a terminal used in a communication system that adds a different type of communication in addition to the type of communication initially performed using a base station and a single radio link,
According to the type of communication, comprising a transmission means for transmitting a service identifier that identifies the type of communication,
The terminal according to claim 1, wherein the transmission means transmits the service identifier through a subchannel which is a communication channel in the OFDMA scheme. In a communication system in which a base station and a terminal are connected by a single radio link for communication, in addition to the type of communication initially performed using the single radio link, a type of communication different from the communication is performed. A communication method to add,
According to the type, transmitting a service identifier identifying the type;
Receiving the service identifier;
Assigning a transmission queue for storing communication data for each type according to the received service identifier;
A communication method comprising:

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