Communication terminal

Technical Field

0001The present invention relates to a communication terminal for communicating in accordance with a predetermined procedure.

Background Art

0002In E-UTRA/E-UTRAN standardized at present, time multiplex is adopted in both an up link (UL) from a terminal to a base station and a down link (DL) from the base station to the terminal. In up link, when the base station receives data from a plurality of terminals, if the reception timings of the data transmitted by the terminals shift, time multiplex cannot efficiently be executed. Thus, in a time multiplex system, the transmission timings of the terminals need to be adjusted so that the base station can receive the data transmitted by the terminals within a given delay.

0003This is called uplink synchronization (also called timing adjustment, timing alignment, etc.). The operation required for each terminal to achieve uplink synchronization is a RACH procedure (Random Access CHannel procedure). First, an outline of the RACH procedure will be described and then Message 3 transmission on which the invention focuses attention will be described.

[Outline of RACH procedure]

0004In E-UTRA/E-UTRAN, the RACH procedure is used in various cases. The use reasons of the RACH procedure are specifically call connection (initial access), Handover complete, message transmission, UL/DL data transmission and reception resuming (UL/DL data resuming), and reconnection (radio link failure recovery).

0005The initial access is the case where the terminal performs call connection from an idle (RRC_IDLE) state. Since the terminal is in IDLE state, uplink synchronization with the base station is not achieved.

0006The Handover complete transmission is the case where the terminal executes handover and the target base station is notified that the terminal moves to the target base station. The terminal has not connected to the target base station until then and thus here achieves synchronization with the target base station.

0007UL/DL data resuming is the case where the terminal performing intermittent reception (DRX) starts to transmit or receive UL or DL data. Since uplink synchronization of the terminal is got out after a while, it is necessary to again achieve synchronization.

0008Radio link failure recovery is the case where after it becomes impossible for the terminal to detect the connected cell, the terminal reconnects to a cell that is newly found (or that has been connected before). The situation resembles initial access.

0009There are two large types of RACH procedure. One is the case where the terminal selects RACH preamble transmitted to the base station on its own (non-dedicated RACH preamble case) and the other is the case where the terminal uses RACH preamble given from the base station (dedicated RACH preamble case).

0010The respective operations are shown in (a) and (b) of <figref idref="f0001">FIG. 1</figref>. The large difference is as follows: In the non-dedicated RACH preamble case, there is a possibility that a plurality of terminals may use the same RACH preamble at the same time and thus a message for checking the presence or absence of collision (Message 4: Contention resolution) is used; in the dedicated RACH preamble case, RACH preamble to be used is assigned by an assignment message (Message 0: RA preamble assignment).

0011To Message 1 and Message 2, the same applies to all cases, but in Message 3 and Message 4, different data is transmitted in response to each case. Only Handover complete transmission and DL data resuming can use dedicated RACH preamble, because the base station can perform the operation of assigning RACH preamble only in the two cases.

0012<figref idref="f0002">FIG. 2</figref> shows the two procedures. Dedicated RACH preamble is not always used for Handover complete transmission or DL data resuming and non-dedicated RACH preamble can be used.

0013Another large difference between non-dedicated RACH preamble and dedicated RACH preamble is that when the base station receives dedicated RACH preamble, it can identify the terminal. Accordingly, work for checking which terminal sends RACH preamble in the later message becomes unnecessary.

0014In other words, in the non-dedicated RACH preamble case, the ID of the terminal needs to be contained in Message 3 to indicate which terminal accesses. As the ID of the terminal, if the terminal is active (RRC_CONNECTED), C-RNTI (Controlling Radio Network Temporary Id) used in cell units is used; if the terminal executes initial access, S-TMSI (S-Temporary Mobile Subscriber Id entity) used in Tracking area (unit of move management of IDLE terminal) or IMSI (International Mobile Subscriber Identity) of the ID unique to the terminal (corresponding to telephone number) is used. In radio link failure recovery, the cell identifier (cell ID) of the cell connected before radio link failure is caused to occur, C-RNTI in the cell, etc., is used.

[Message 3 transmission]

0015Data that can be initially transmitted to the base station by the terminal is Message 3, and information for this is assigned in Message 2. However, it is known that the size of Message 3 is about 72 bits if the terminal is in a cell edge.

0016Thus, it is considered that it is difficult to transmit all information at one time. To show how Message 3 is configured, <figref idref="f0003">FIGs. 3</figref>, <figref idref="f0004">4</figref>, and <figref idref="f0005">5</figref> show header configurations of MAC (Medium Access Control), RLC (Radio Link Control), and PDCP (Packet Data Convergence Protocol) respectively. <figref idref="f0014">FIG. 14</figref> shows the configuration of protocol. An outline is described below:

(MAC)

0017Three types of MAC sub-headers are provided and the minimum sub-header is eight bits. What data is contained is indicated using LCID (Logical Channel ID), whether or not a MAC sub-header exists following a MAC sub-header is indicated in an E (Extention) field), and the data size is indicated in an L (Length) field).

0018MAC control element (MAC control information: as up link, C-RNTI, Buffer status report (BSR indicating the buffer status of the terminal), and CQI (Channel Quality Indicator indicating the channel status of the terminal) are also indicated in LCID. In this case, the size is predetermined and thus the L field is not required.

(RLC)

0019A 16-bit header is defined for RLC AM (acknowledge mode) and 16 bits (10-bit SN for long data) and eight bits (five-bit SN for short data) are defined for RLC UM (unacknowledged mode).

(PDCP)

0020Different headers are defined in SRB (signalling radio bearer: Bearer for carrying an RRC message of a control message) and data radio bearer (DRB, bearer for carrying data). For SRB, a 40-bit header becomes necessary.

0021The data radio bearer may be called user plane radio bearer (user radio bearer).

0022It is considered that Handover complete contains message type (indicating the type of message), transaction id (indicating response to which message), etc., as RRC message, and eight bits are assumed.

0023Non-patent Document 1: TS25.321: "Medium Access Control (MAC) protocol specification" Similarly, <nplcit id="ncit0001" npl-type="s"><text>3GPP TS 36.321 v8.0.0, "Medium Access Control (MAC) protocol specification specifies MAC PDU format and mapping from logistical channels to transport channels for E-UTRA</text></nplcit>.

Disclosure of the Invention

Problems to be Solved by the Invention

0024From the description given above, considering transmission of Handover complete, it is seen that if 72 bits only are assigned to the terminal for transmission, transmission needs to be executed twice as in Table 1. It is predetermined that BSR is transmitted after Handover is executed. In UMTS (Universal Mobile Telecommunication System), it is assumed that MAC control information (MAC control element in LTE) always has higher priority than SRB and DRB (refer to Non-patent Document 1).

0025Thus, it is assumed that the BSSR is sent earlier than Handover complete. In this case, transmission is executed three times as in Table 2 and further transmission of Handover complete is delayed.

[Table 1]

0026<tables id="tabl0001" num="0001"><table frame="all"><title>Table 1: To transmit Handover complete only</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="26mm" /><colspec colnum="2" colname="col2" colwidth="33mm" /><colspec colnum="3" colname="col3" colwidth="33mm" /><thead><row><entry valign="top" /><entry valign="top">1st segment</entry><entry valign="top">2nd segment</entry></row></thead><tbody><row><entry>RRC+PDCP</entry><entry>24 bits</entry><entry>24 bits</entry></row><row><entry>RLC</entry><entry>16 bits</entry><entry>16 bits</entry></row><row><entry>MAC</entry><entry>8 bits (LCID for RRC)</entry><entry>8 bits (LCID for RRC)</entry></row><row><entry>PHY (CRC)</entry><entry>24 bits</entry><entry>24 bits</entry></row><row><entry>Total</entry><entry>72 bits</entry><entry>72 bits</entry></row></tbody></tgroup></table></tables>

[Table 2]

0027<tables id="tabl0002" num="0002"><table frame="all"><title>Table 2: When BSR takes precedence over Handover complete</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="26mm" /><colspec colnum="2" colname="col2" colwidth="76mm" /><colspec colnum="3" colname="col3" colwidth="33mm" /><colspec colnum="4" colname="col4" colwidth="33mm" /><thead><row><entry valign="top" /><entry valign="top">1st segment</entry><entry valign="top">2nd segment</entry><entry valign="top">3rd segment</entry></row></thead><tbody><row><entry>RRC+PDCP</entry><entry>0 bits</entry><entry>24 bits</entry><entry>24 bits</entry></row><row><entry>RLC</entry><entry>0 bits</entry><entry>16 bits</entry><entry>16 bits</entry></row><row><entry>MAC</entry><entry>48 bits (LBSR+LCID + 24 bits padding (LCID + padding bits)</entry><entry>8 bits (LCID for RRC)</entry><entry>8 bits (LCID for RRC)</entry></row><row><entry>PHY (CRC)</entry><entry>24 bits</entry><entry>24 bits</entry><entry>24 bits</entry></row><row><entry>Total</entry><entry>72 bits</entry><entry>72 bits</entry><entry>72 bits</entry></row></tbody></tgroup></table></tables>

0028As described above, if MAC control element (for example, BSR) takes priority, it is through that transmission of Handover complete is delayed. This has the following disadvantage:

(Path switching delay in network)

0029As the base station receives Handover complete, it can reliably determine that the terminal moves. Thus, switching in the network (path switching from the former base station to a new base station) is performed at the timing at which Handover complete is received. If path switching is delayed, data, etc., not transferred from the former base station to the new base station is discarded.

0030<figref idref="f0015">FIG. 15</figref> shows the relationship between the base station in the network and the entity of a core network. The core network entity continues to transmit data to the previous base station (source eNB) until path is switched to the core network entity.

0031There is no problem if the previous base station transfers data to a new base station; for example, it is thought that a packet is not transferred in real time service of VoIP, etc. To minimize this, shortening of path switching delay is demanded.

(Transmission start delay of down link)

0032As the base station receives Handover complete, it can reliably determine that the terminal moves, and can start down link data transmission. Thus, if reception of Handover complete is delayed, when there is data transferred from the former base station to a new base station, down link data transmission start is delayed.

0033Considering the description given above, it is undesirable that the MAC control element always takes precedence. Thus, the priority of the MAC control element needs to be controlled.

0034In view of the circumstances described above, it is an object of the invention to provide a communication terminal and a base station that can assign priority to MAC control information and can control what information is to be transmitted as desired.

Means for Solving the Problems

0035This object is achieved by the present invention as claimed in the independent claim. Advantageous and preferred embodiments of the present invention are defined by the dependent claims.

Brief Description of the Drawings

0036<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> shows the operation of non-dedicated RACH preamble and dedicated RACH preamble.</li><li><figref idref="f0002">FIG. 2</figref> shows procedures of handover complete transmission and DL data resuming.</li><li><figref idref="f0003">FIG. 3</figref> shows the header configuration of MAC of Message 3.</li><li><figref idref="f0004">FIG. 4</figref> shows the header configuration of RLC of Message 3.</li><li><figref idref="f0005">FIG. 5</figref> shows the header configuration of PDCP of Message 3.</li><li><figref idref="f0006">FIG. 6</figref> shows the concept of Embodiment 2 of the invention.</li><li><figref idref="f0007">FIG. 7</figref> is a block diagram of a terminal according to Embodiment 2 of the invention.</li><li><figref idref="f0008">FIG. 8</figref> shows a specific example of a procedure according to Embodiment 2 of the invention.</li><li><figref idref="f0009">FIG. 9</figref> shows the concept of Embodiment 3 of the invention.</li><li><figref idref="f0010">FIG. 10</figref> is a block diagram of a terminal according to Embodiment 3 of the invention.</li><li><figref idref="f0011">FIG. 11</figref> describes change of priority of MAC control element for each use reason of a RACH procedure in Embodiment 3 of the invention.</li><li><figref idref="f0012">FIG. 12</figref> shows the concept of Embodiment 4 of the invention.</li><li><figref idref="f0013">FIG. 13</figref> is a block diagram of a terminal according to Embodiment 4 of the invention.</li><li><figref idref="f0014">FIG. 14</figref> shows the configuration of protocol of Message 3.</li><li><figref idref="f0015">FIG. 15</figref> shows the relationship between a base station in a network and the entity of a core network.</li><li><figref idref="f0016">FIG. 16</figref> shows an outline of setting priority for each MAC control element in Embodiment 1 of the invention.</li><li><figref idref="f0017">FIG. 17</figref> is a block diagram of a terminal according to Embodiment 1 of the invention.</li><li><figref idref="f0018">FIG. 18</figref> shows an example of MAC control element priority table and an example of boundary information in Embodiment 2 of the invention.</li><li><figref idref="f0019">FIG. 19</figref> shows operation when a base station considers the speed of a terminal in Embodiment 2 of the invention.</li><li><figref idref="f0020">FIG. 20</figref> shows operation of temporarily changing priority in Embodiment 2 of the invention.</li><li><figref idref="f0021">FIG. 21</figref> shows a method of transmitting boundary information used for transmission using semi-persistent scheduling to a terminal in Embodiment 3 of the invention.</li><li><figref idref="f0022">FIG. 22</figref> is a block diagram of a terminal according to Embodiment 5 of the invention.</li><li><figref idref="f0023">FIG. 23</figref> is a flowchart to show the essence of operation according to Embodiment 5 of the invention.</li><li><figref idref="f0024">FIG. 24</figref> shows a flow when the terminal executes initial access (call connection), Radio link failure recovery (reconnection) in Embodiment 2 of the invention.</li><li><figref idref="f0025">FIG. 25</figref> shows the configuration of a MAC sub-header used in a conventional proposition.</li><li><figref idref="f0026">FIG. 26</figref> shows the configuration of a MAC sub-header according to conventional proposition 1.</li><li><figref idref="f0027">FIG. 27</figref> shows the configuration of a MAC sub-header according to Embodiment 6 of the invention.</li><li><figref idref="f0027">FIG. 28</figref> is a flowchart to show an outline of the operation of a terminal according to Embodiment 6 of the invention.</li><li><figref idref="f0028">FIG. 29</figref> shows configuration examples of MAC header according to Embodiment 6 of the invention.</li><li><figref idref="f0029">FIG. 30</figref> shows a definition example of LCID according to Embodiment 6 of the invention.</li><li><figref idref="f0030">FIG. 31</figref> shows other configuration examples of MAC header according to Embodiment 6 of the invention.</li></ul>

Description of Reference Numerals and Signs

0037<dl id="dl0001" compact="compact"><dt>701, 2201</dt><dd>Reception section</dd><dt>702, 1101</dt><dd>Priority table section</dd><dt>703, 1001, 1301, 1701, 2202</dt><dd>Priority control section</dd><dt>704, 1002, 1302, 2203</dt><dd>Transmission message generation section</dd><dt>705</dt><dd>SRB generation section</dd><dt>706</dt><dd>DRB generation section</dd><dt>707</dt><dd>Buffer section</dd><dt>708</dt><dd>MAC information generation section</dd><dt>709</dt><dd>Transmission section</dd></dl>

Best Mode for Carrying out the Invention

0038An example wherein the priority of transmission data is defined before execution of RACH procedure by a base station and a terminal will be described below: Embodiments described below can be applied to the non-dedicated RACH preamble case and the dedicated RACH preamble case in a similar manner.

(Embodiment 1)

0039SRB (signalling radio bearer: bearer for carrying an RRC message of a control message) and DRB (user plane radio bearer/data radio bearer: bearer for carrying data) have each a priority. As present SRB, high priority SRB (SRB2) for sending an RRC message having a high priority and low priority SRB (SRB1) having a priority as usual SRB exist for an RRC_CONNECTED terminal to communicate. Another SRB (SRB0) is defined for carrying an RRC message until a terminal moves to RRC_CONNECTED in initial access, Radio link failure recovery, etc. DRB is added in response to service used by the terminal; for example, DRB for VoIP, DRB for web browsing, DRB for transferring email, and the like are set.

0040Priority is set for each bearer so that the base station can control which bearer the terminal may transmit. Basically, SRB has a higher priority than DB. In DRB, a bearer for service involving strict requirement for a delay (time critical service) has a high priority. Thus, in the example, the following priority is considered:

High priority SRB > low priority SRB > DRB for VoIP > DRB for web browsing > DRB for email

0041In the embodiment, priority is set for each MAC control element as like SRB and DRB. An outline is shown in <figref idref="f0016">FIG. 16</figref>. As shown in the figure, for example, if priority values are 1 to 8 and 1 is the highest, it is considered that C-RNTI considered to be the highest priority in the MAC control element is set to priority 1 and BSR, CQI, etc., considered to be next highest priority is set to priority 3.

0042If the priority of high priority SRB becomes 2, only C-RNTI takes precedence over high priority SRB. According to such operation, it is made possible to control what information the terminal is caused to transmit as desired.

0043Specifically, if the terminal uses VoIP and path switching needs to be made rapid, it is considered that the priority of high priority SRB is made higher than that of BSR. Conversely, if path switching need not be made rapid and the buffer state that the terminal has is to be grasped rapidly, the priority of BSR can be made higher than that of high priority SRB.

(Block diagram)

0044<figref idref="f0017">FIG. 17</figref> is a block diagram of a terminal of the invention. The communication terminal shown in <figref idref="f0017">FIG. 17</figref> includes a reception section 701, an SRB generation section 705, a DRB generation section 706, a priority control section 1701, a transmission message generation section 704, a buffer section 707, a MAC information generation section 708, and a transmission section 709. The main operation and the roles of the sections are as follows:

0045The reception section 701 receives a message from a base station. The reception section 701 receives the priority for each MAC control element and sends the priority to the priority control section 1701. The reception section 701 receives the message size transmitted by the terminal and sends the message size to the transmission message generation section 704. The SRB generation section 705 creates a message to be transmitted using SRB of an RRC message, a NAS message, etc. The DRB generation section 706 creates user plane data.

0046The priority control section 1701 receives the priority for each MAC control element from the reception section 701. The priority control section 1701 defines the priority relationship between MAC control element and SRB such as "C-RNTI > SRB > BSR > CQI > DRB" or "C-RNTI > high priority SRB > BSR > low priority SRB > CQI > DRB" according to the priority for each MAC control element and the priority assigned usually to DRB and SRB. The priority control section 1701 uses the result to control the transmission message generation section 704 so as to create a transmission message for transmitting high priority information early.

0047The transmission message generation section 704 creates a transmission message based on the priority information from the priority control section 1701 and the transmission message size from the reception section 701. The transmission message generation section 704 receives MAC control element from the MAC information generation section 708 described later, reports transmittable bearer and the amount to the buffer section 707, and receives information to be transmitted of SRB or DRB from the buffer section 707.

0048The buffer section 707 holds information from the SRB generation section 705 and the DRB generation section 706 and transmits the information to the transmission message generation section 704 in response to a command of the transmission message generation section 704.

0049The MAC information generation section 708 generates MAC control element and reports the MAC control element to the transmission message generation section 704. Specifically, when C-RNTI needs to be transmitted, the MAC information generation section 708 passes C-RNTI to the transmission message generation section 704. When BSR needs to be transmitted, the MAC information generation section 708 generates and transmits BSR from information of the buffer section 707. The transmission section 709 has a role of transmitting a message created by the transmission message generation section 704 to the base station.

0050As described above, according to the embodiment, the priority can be set as desired for each MAC control element, so that data to be transmitted preferentially to the base station in Message 3 of RACH procedure can be appropriately controlled in response to the description and the situation of communication service.

(Embodiment 2)

0051<figref idref="f0006">FIG. 6</figref> shows the concept of Embodiment 2, <figref idref="f0007">FIG. 7</figref> is a block diagram of a terminal, and <figref idref="f0008">FIG. 8</figref> shows a specific example of a procedure of the operation.

0052In Embodiment 1, the priority can be set as desired for each MAC control element. However, the system of Embodiment 1 involves a problem in that the overhead of signalling for the base station to set priority for the terminal increases. In Embodiment 2, priority in MAC control element is previously determined and only the boundary between the MAC control element having a high priority for SRB and the MAC control element having a low priority is set, whereby the problem is solved. <figref idref="f0006">FIG. 6</figref> shows an outline.

0053As by (a) in <figref idref="f0006">FIG. 6</figref>, priority is determined in MAC control elements. It is considered that the priority is stipulated in the specification (spec) of standardization, etc.; it may be transmitted in report information, etc., or may be sent in a discrete RRC message. In the embodiment, an example wherein the priority is stipulated in the specification (spec) of standardization, etc., will be described. The boundary between the MAC control element having a higher priority than SRB and the MAC control element having a lower priority than SRB is set. Specifically, any of boundaries 1 to 4 in the example by (a) in <figref idref="f0006">FIG. 6</figref> is specified. A signalling example at this time is shown by (b) in <figref idref="f0006">FIG. 6</figref>. The procedure shown by (b) in <figref idref="f0006">FIG. 6</figref> is executed before Message 1 shown by (a) in <figref idref="f0001">FIG. 1</figref>.

0054Specifically, if boundary 2 is specified, the priority order becomes as follows: C-RNTI > SRB > BSR > CQI > DRB

0055Although one priority is under SRB, it is also considered that the priority of the MAC control element is compared with high priority SRB for setting as follows: C-RNTI > high priority SRB > BSR > low priority SRB > CQI > DRB

(Block diagram)

0056<figref idref="f0007">FIG. 7</figref> is a block diagram of the terminal of the embodiment. The terminal shown in <figref idref="f0007">FIG. 7</figref> includes a priority control section 703 and a priority table section 702 in place of the priority control section 1701 of the terminal shown in <figref idref="f0017">FIG. 17</figref>. Difference of the main operation and the role of each section from those of Embodiment 1 will be described.

0057In Embodiment 2, a reception section 701 has a role of receiving boundary information described above and reports the boundary information to the priority control section 703 in addition to the role described in Embodiment 1.

0058The priority table section 702 has a role of holding information of priority in MAC control elements shown by (a) in <figref idref="f0006">FIG. 6</figref> and reporting the information to the priority control section 703.

0059The priority control section 703 defines the priority relationship between MAC control element and SRB such as "C-RNTI > SRB > BSR > CQI > DRB" or "C-RNTI > high priority SRB > BSR > low priority SRB > CQI > DRB" according to the boundary information from the reception section 701 and the priority table section information from the priority table section 702. The priority control section 703 uses the result to control the transmission message generation section 704 so as to transmit high priority information early.

(Detailed description)

0060The operation of the invention will be described with <figref idref="f0007">FIGs. 7</figref> and <figref idref="f0008">8. FIG. 8</figref> shows a specific example of procedure of handover transmission.

0061As shown in <figref idref="f0008">FIG. 8</figref>, first, boundary information is reported from a base station (Source cell) to a terminal (UE) (ST8-1: RRC CONNECTION RECONFIGURATION message). The boundary information is received by the reception section 701 and is passed to the priority control section 703. The priority control section 703 obtains information of the priority of MAC control element from two pieces of information of the boundary information received in ST8-1 and table indicating the priority in MAC control elements described by (a) in <figref idref="f0006">FIG. 6</figref> held in the priority table section 702. The priority control section 703 sends the information to the transmission message generation section 704.

0062Next, a response message to ST8-1 created in the transmission message generation section 704 is transmitted from a transmission section 709 of the terminal to the base station (ST8-2: RRC CONNECTION RECONFIGURATION COMPLETE message).

0063The base station reports execution of Handover to the terminal (ST8-3: Handover Command message). The terminal executes handover in response to it. The processing is general operation and does not directly relate to the invention and thus will not be described.

0064Handover Command and Handover Complete message are generic terms of a Handover command message for the terminal by the base station and a message for the terminal to indicate completion of Handover for the base station respectively. In E-UTRA/E-UTRAN, RRC CONNECTION RECONFIGURATION message and RRC CONNECTION RECONFIGURATION COMPLETE message are used.

0065ST8-4: Random Access preamble and ST8-5: Random Access response executed after ST8-3 are usual RACH procedure and will not be described in detail. After ST8-5, the transmission message generation section 704 determines the message size in Message 3 based on resource allocation information received in ST8-5. The message size is sent from the reception section 701 to the transmission message generation section 704.

0066If both Handover complete and BSR are to be sent and cannot be contained in one message, which takes precedence is determined depending on the priority. That is, if BSR > SRB, BSR takes precedence over SRB and if BSR < SRB, Handover complete takes precedence. Thus, the description sent in ST8-6, ST8-8 becomes Handover complete or BSR depending on the priority determined by the priority control section 703.

0067In <figref idref="f0018">FIG. 18</figref>, (a) and (b) show an example of a MAC control element priority table and an example of boundary information respectively. Thus, the MAC control element priority is provided as the table and the RRC message priority (it may be only high priority SRB, both high priority SRB and low priority SRB, or only low priority SRB) is reported in the boundary information and thus the description to be transmitted can be controlled.

0068Next, how the base station determines the boundary information will be described. As described above, transmission delay of Handover Complete message causes delay of path switching in the network. Real time service such as VoIP not transferring data from the source base station to the Handover target base station as described above is largely affected by the delay of path switching.

0069Thus, processing in which only a terminal executing VoIP takes precedence in transmission of Handover Complete is considered. Effectiveness of terminal information transferred between base stations as information for switching a path is also considered. At the time of Handover, terminal information is transferred between the base stations.

0070At this time, information of the reception quality of the terminal, the buffer state of the terminal, etc., is also transferred. If the move speed of the terminal is not so high and the reception quality of the terminal is sufficient as information transferred between the base stations, it is considered that the priority of CQI is lowered; conversely, if the move speed of the terminal is high, it is considered that the priority of CQI is raised.

0071Service in which the buffer state easily varies and a service in which the buffer state hardly varies are considered. For example, in service of VoIP, etc., the buffer state does not so much vary. In contrast, to execute upload, it is considered that the buffer state largely varies.

0072Thus, it is considered that if only service in which the buffer state hardly varies is executed, the priority of BSR is lowered and if service in which the buffer state easily varies is executed, the priority of BSR is raised. Such operation makes it possible to control information to be transmitted by the terminal.

0073In the embodiment, one boundary is set for MAC control element by way of example, but the number of boundaries to be set can also be increased. Specifically, it is also considered that the boundary for high priority SRB (for example, boundary 2 by (a) in <figref idref="f0006">FIG. 6</figref>) and the boundary for low priority SRB (for example, boundary 3 by (a) in <figref idref="f0006">FIG. 6</figref>) are set and priority is set such as "C-RNTI > high priority SRB > BSR > CQI > low priority SRB > DRB."

0074In the embodiment, priority of MAC control element can be set only for SRB. Alternatively, it can also be set for DRB having the highest priority. That is, processing such as "C-RNTI > SRB > BSR > high priority DRB > CQI > other DRB" can be realized by providing a plurality of pieces of boundary information.

0075In the embodiment, the transmission example of Handover complete is shown, but it can also be applied to other cases. As a specific example, UL data resuming can be named. UL data resuming is operation in the case of occurrence of data transmitted during DRX by the terminal.

0076Specifically, it is considered that the measurement result indicating the reception state of the terminal (Measurement report as RRC message) is transmitted and a service request for addition of a new service (service request, etc., as NAS message) is sent. The Measurement report indicating the measurement result is required for execution of Handover and thus is a message having a high priority.

0077Thus, if the move speed of the terminal is high, the message must be sent early. As described above, as the base station considers the move speed of the terminal, at the time, whether occurred data is to be sent or BSR or CQI takes precedence can be determined according to the processing shown in the embodiment. The operation at the time is shown in <figref idref="f0019">FIG. 19</figref>.

0078The priority of MAC control element can also be made as the order of LCID. As described above, each MAC control element is indicated by LCID. For example, BSR is 11100, CQI is 11101, etc. The order of LCID is defined so as to become the priority order, whereby the need for specially providing a priority table in the terminal is eliminated.

0079In the embodiment, notification of Handover Command and Boundary information is separate messages as shown in <figref idref="f0008">FIG. 8</figref>, but Boundary information can be reported or changed in Handover Command.

0080In the embodiment, the operation of setting so as to raise the priority of RRC message when the terminal executes VoIP and Handover complete should take precedence, etc., is shown. However, there is a problem in that the situation varies in Handover between cells in the same base station.

0081The reason is that the need for transmitting Handover complete early is eliminated because switching of the base station does not occur. To realize this, the operation of temporarily changing priority is considered.

0082<figref idref="f0020">FIG. 20</figref> shows the operation in this case. The operation differs largely from the operation in <figref idref="f0008">FIG. 8</figref> in that temporary priority is assigned at ST20-1 corresponding to ST8-3. The temporary priority is applied only to response to ST20-1: Handover Command transmitted by the base station and is applied only to Handover Complete.

0083In the description of the invention, attention is focused on Message 3 of the RACH procedure, but the embodiment can be applied to all usual uplink transmission.

0084As a typical example when the embodiment is used for all usual uplink transmission, it is considered that the terminal executes initial access (call connection), Radio link failure recovery (reconnection). A flow is shown in <figref idref="f0024">FIG. 24</figref>. When the terminal executes call connection or reconnection, the network does not precisely know the reception state of the terminal, etc. Thus, information of CQI, etc., is required.

0085On the other hand, however, information sent to Core network is entered in the signal sent by the terminal at ST2406a and if it is not sent, finally call connection does not terminate. On the other hand, ST2406b is mainly used for acknowledgment response only.

0086Thus, boundary information given at ST2404a, ST2404b makes possible the operation such that SRB (namely, RRC CONNECTION SETUP COMPLETE) takes precedence at the time of initial access. Accordingly, the problem in that delay of call connection increases because of transmission of MAC control element can be solved.

(Embodiment 3)

0087<figref idref="f0009">FIG. 9</figref> shows the concept of Embodiment 3 and <figref idref="f0010">FIG. 10</figref> is a block diagram of a terminal. Embodiment 2 shows the case where the same priority setting is used for all cases using the RACH procedure. However, since necessary information slightly varies for the use reason of RACH procedure, it is considered that the priority is determined for each reason executing the RACH procedure. Embodiment 3 makes it possible to control transmission data more appropriately in response to the use reason of the RACH procedure. A priority determination example for each reason executing the RACH procedure is shown below:

(Transmission of Handover complete)

0088It is considered that if BSR is not so much changed, BSR reported from the source base station to the target base station can be used. Thus, it is considered that Handover complete (namely, SRB) takes precedence.

(Uplink transmission start delay)

0089To know how much information the terminal has, BSR becomes necessary. Thus, it is considered that BSR takes precedence over SRB.

(Downlink transmission start delay)

0090To execute downlink transmission, it is considered that CQI is required. Thus, it is considered that CQI takes precedence.

0091In <figref idref="f0009">FIG. 9</figref>, (b) shows the information indication operation to realize this. Boundary information is thus determined for each use reason of the RACH procedure, so that it is made possible to change the operation for each RACH procedure.

(Block diagram)

0092<figref idref="f0010">FIG. 10</figref> is a block diagram of the terminal of the embodiment. The terminal shown in <figref idref="f0010">FIG. 10</figref> includes a priority control section 1001 and a transmission message generation section 1002 in place of the priority control section 703 and the transmission message generation section 704 of the terminal shown in <figref idref="f0007">FIG. 7</figref>. Only the difference will be described. The priority control section 1001 can have different priority setting for each reason of RACH procedure and reports it to the transmission message generation section 1002. The transmission message generation section 1002 generates a transmission message using different priority setting for each reason of the RACH procedure.

0093In the embodiment, only boundary information is set for each reason of the RACH procedure by way of example, but the priority of MAC control element can also be changed for each use reason of the RACH procedure. In this case, as shown in <figref idref="f0011">FIG. 11</figref>, a priority table section 1101 may be included in place of a priority table section 702 shown in <figref idref="f0010">FIG. 10</figref> and the priority for each use reason of the RACH procedure may be set in the priority table section 1101.

0094Specifically, the following examples are considered: <ul id="ul0002" list-style="none" compact="compact"><li>Handover complete: C-RNTI > BSR > CQI</li><li>UL data resuming: C-RNTI > BSR > CQI</li><li>DL data resuming: C-RNTI > CQI > BSR</li></ul>

0095The operation using different priority depending on the use reason (cause) of the RACH procedure shown in the embodiment can also be applied to the case where different priority is set in dynamic scheduling and semi-persistent scheduling although the bearer is the same bearer. In E-UTRA/E-UTRAN, dynamic scheduling for assigning data in PDCCH (Physical Downlink Control Channel) each time and semi-persistent scheduling for continuing to use the resource in a given period if data is once assigned in PDCCH. The semi-persistent scheduling is suited for service in which data is sent in the same size on a regular basis such as VoIP. However, there is a problem in that if an attempt is made to transmit information of BSR, CQI, etc., taking precedence over data of VoIP, they cannot be entered in the resource assigned in the semi-persistent scheduling and data of VoIP cannot be sent at a time. Then, the priority for MAC control element is also applied to DRB and further priority setting is changed by a scheduling method for DRB, whereby the problem can be solved. Specifically, a method of transmitting boundary information used for transmission using the semi-persistent scheduling to the terminal is considered (<figref idref="f0021">FIG. 21</figref>). That is, if boundary 1 is indicated, in the terminal, VoIP data takes precedence over BSR and CQI only at the time of the semi-persistent scheduling, and BSR and CQI take precedence as usual in the dynamic scheduling.

(Embodiment 4)

0096<figref idref="f0012">FIG. 12</figref> shows the concept of Embodiment 4. <figref idref="f0013">FIG. 13</figref> is a block diagram of a terminal. Embodiment 2 provides means for enabling SRB to take precedence over MAC control element. However, the size of a message taking precedence over MAC control element is large, it is considered that it is better to send MAC control element early.

0097Thus, in the embodiment, only if the message taking precedence over MAC control element is smaller than a predetermined size, SRB takes precedence over MAC control element. The threshold for the message size is sent together with boundary information as shown by (b) in <figref idref="f0012">FIG. 12</figref>.

(Block diagram)

0098<figref idref="f0013">FIG. 13</figref> is a block diagram of a terminal of the embodiment. The terminal shown in <figref idref="f0013">FIG. 13</figref> includes a priority control section 1301 and a transmission message generation section 1302 in place of the priority control section 703 and the transmission message generation section 704 shown in <figref idref="f0007">FIG. 7</figref>. Only the difference will be described below: The priority control section 1301 receives and processes the threshold to determine whether or not to transmit SRB or DRB taking precedence over MAC control element and sends the threshold to the transmission message generation section 1302. The transmission message generation section 1302 determines whether or not the size of SRB or DRB taking precedence falls below the threshold and only when the size falls below the threshold, the transmission message generation section 1302 creates a transmission message so as to transmit SRB or DRB taking precedence over MAC control element.

(Embodiment 5)

0099<figref idref="f0022">FIG. 22</figref> is a block diagram of a terminal of Embodiment 5 and <figref idref="f0023">FIG. 23</figref> is a flowchart to show an outline of operation. Embodiment 2 shows the method of determining the priority of MAC control element and SRB according to a command from the network. Embodiment 5 shows the operation of determining the priority without a command from a network.

(Block diagram)

0100<figref idref="f0022">FIG. 22</figref> is a block diagram of a terminal of the embodiment. The terminal shown in <figref idref="f0022">FIG. 22</figref> includes a reception section 2201, a priority control section 2202, and a transmission message generation section 2203 in place of the reception section 701, the priority control section 703, and the transmission message generation section 704.

0101Unlike the reception section 701, the reception section 2201 does not receive boundary information and does not report it to the priority control section 703, but sends information necessary for determining the priority of MAC control element and SRB to the priority control section 2202. The information necessary for determining the priority of MAC control element and SRB is information as to whether or not service in which packet loss increases because of path switching delay such as VoIP is received, whether Handover is Handover in a base station or Handover between base stations, etc.

0102Unlike the priority control section 703, the priority control section 2202 determines the priority of SRB and MAC control element based on information received from the reception section 2201. The priority is determined when the transmission message generation section 2203 creates a transmission message.

0103The transmission message generation section 2203 reports the contents of a message scheduled to be transmitted to the priority control section 2202. The transmission message generation section 2203 checks the priority in the priority control section 2202 each time it creates a transmission message.

(Flowchart)

0104<figref idref="f0023">FIG. 23</figref> shows the operation of determining the priority of SRB and MAC control element based on whether or not VoIP is used and whether or not Handover is Handover between base stations when Handover complete is transmitted.

0105At ST2301, transmission of Handover complete from the transmission message generation section 2203 of the terminal to the base station is started. The transmission message generation section 2203 checks the priority in the priority control section 2202.

0106The priority control section 2202 determines whether or not VoIP is used at ST2302. If VoIP is not used, the priority control section 2202 goes to ST2304; if VoIP is used, the priority control section 2202 goes to ST2303. At ST2303, the priority control section 2202 determines whether the Handover is Handover between base stations or Handover within base station. If the Handover is Handover within base station at ST2303, the priority control section 2202 goes to ST2304; if the Handover is Handover between base stations, the priority control section 2202 goes to ST2305.

0107At ST2304, the priority control section 2202 determines that MAC Control element takes precedence as path switching delay caused by Handover Complete delay does not introduce a problem. Conversely, at ST2305, the priority control section 2202 determines that Handover complete takes precedence because Handover Complete delay introduces a problem. The result is reported to the transmission message generation section 2203, which then generates a transmission message based on the result.

0108In the embodiment, the terminal determines the priority for MAC control element of SRB based on whether or not VoIP is executed and whether or not Handover is Handover between base stations, but any other condition may be used. Specifically, it is also considered that if the move speed of the terminal is high, CQI takes precedence and if the move speed is low, CQI does not take precedence. It is also considered that if variation of the buffer state in the terminal is fierce, BSR takes precedence and variation is not fierce, BSR does not take precedence.

0109In the embodiment, whether or not VoIP is executed is adopted as one criterion of determination, but determination may be made simply based on whether or not service not transferred between base stations exists. DRB using UM of RLC is not transferred. Thus, whether or not DRB using UM of RLC exists can be used as a determination criterion.

0110Further, whether or not DRB using RLC UM is equal to or greater than one priority can be used as a determination criterion. Accordingly, determination of the priority of SRB affected by DRB of RLC UM having a low priority can be circumvented.

(Embodiment 6)

0111<figref idref="f0027">FIG. 27</figref> shows the configuration of a MAC sub-header of Embodiment 6 and <figref idref="f0027">FIG. 28</figref> is a flowchart to show an outline of the operation of a terminal. The embodiment shows how a base station distinguishes the description when a terminal selects RACH preamble transmitted to the base station on its own (non-dedicated RACH preamble case).

0112When a terminal selects RACH preamble transmitted to the base station on its own, the base station does not understand whether the terminal wants to execute initial access, wants to transmit Handover complete, or else if it receives only RACH preamble (Message 1 shown by (a) in <figref idref="f0001">FIG. 1</figref>). Thus, the base station knows what the description of Message 3 shown by (a) in <figref idref="f0001">FIG. 1</figref> is at the point in time receiving Message 3. At this time, one problem exists. It is caused by the fact that whether or not header of MAC is used in Message 3 varies depending on a condition. Specifically, if a resource for only sending 72-bit information to the terminal is allocated, header of MAC is not contained and directly RRC message is contained in the case of call connection, or reconnection; header of MAC is contained in Handover complete transmission, UL/DL data transmission-reception resuming. If a resource for sending 144-bit information, for example, larger than 72 bits is allocated, MAC header is contained even in the case of call connection, reconnection. Thus, the base station needs to determine whether or not MAC header is contained if 72 bits only are allocated to the terminal.

0113To solve this, non-patent document (R2-080162: Message 3 encoding) makes two propositions.

(Conventional proposition 1)

0114The first proposition uses the configuration of the present MAC sub-header (see (a) in <figref idref="f0025">FIG. 25</figref>) described in non-patent document (TS36.321 V8.0.0: "Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification") and uses an LCID (Logical Channel IDentifier) field (LCID field) at the top. The LCID field is a location to enter LCID corresponding to carried data or LCID corresponding to MAC control element and according to this, the reception party can identify what the received data is.

0115As a specific method described in the document, the first two bits of five-bit LCID are used to indicate whether or not MAC header exists; for example, if the value of the first two bits is "11," it is assumed that MAC header exists and if the value is "00," "01," or "10" other than "11," it is assumed that MAC header does not exist. In the case of RRC message in call connection, reconnection, namely, RRC CONNECTION REQUEST, RRC CONNECTION RE-ESTABLISHMENT REQUEST, it is considered that the first two bits are used as Message type indicating RRC message. Thus, if the value is "00," "01," or "10," the message received in RRC is identified as RRC CONNECTION REQUEST, RRC CONNECTION RE-ESTABLISHMENT REQUEST. For example, if the value is "00," the message is RRC CONNECTION REQUEST and if the value is "01," the message is RRC CONNECTION RE-ESTABLISHMENT REQUEST.

0116As the disadvantage in this case, the area that can be indicated in LCID is limited. If the terminal selects RACH preamble transmitted to the base station on its own, it needs to report C-RNTI the base station and the information must be contained. Thus, it becomes necessary to reserve eight LCIDs of 32 for MAC control element containing C-RNTI. In fact, however, it is considered that eight MAC control elements containing C-RNTI are not defined, and thus LCIDs are reserved fruitlessly.

0117Here, other fields in the MAC sub-header will be described. An extension field (E) indicates whether or not MAC sub-header further continues. If the value is "0," it indicates that data or MAC control element is entered; if the value is "1," it indicates that MAC sub-header continues. <figref idref="f0026">FIG. 26</figref> shows a configuration example wherein a plurality of MAC sub-headers continue. In <figref idref="f0026">FIG. 26</figref>, (a) shows an example wherein only a MAC sub-header without a length field (L field) shown in <figref idref="f0025">FIG. 25</figref> forms MAC header. The length field indicates the size of data to be sent and enables the reception party to know where the next data or MAC control element begins. The MAC control element has a fixed length and the length field is not required and the last data is not followed by any data and thus the length field need not be entered. There are the two types of length fields: 7-bit length field ((b) in <figref idref="f0026">FIG. 26</figref>) and 15-bit length field ((c) in <figref idref="f0026">FIG. 26</figref>). A format field (F field) indicates which of the two types is used. A reserved bit (R bit) is defined for later extension.

(Conventional proposition 2)

0118The second proposition uses another MAC header configuration (see (b) in <figref idref="f0025">FIG. 25</figref>). The first reserved bit is used to indicate whether or not MAC header exists. That is, if the value is "0," MAC header exists and if the value is "1," MAC header does not exist. In RRC, the first bit is always set to "1" and thus only "10" and "11" can be used for identifying the Message type. If the value is "10," the Message type is RRC CONNECTION REQUEST and if the value is "11," the Message type is RRC CONNECTION RE-ESTABLISHMENT REQUEST.

0119The problem in this case exists in that all Message types are used and thus new RRC message cannot be defined. Thus, it is desirable that the range that can be defined as LCID is not used fruitlessly and an area that can be used for Message type is ensured so that a new RRC message can be defined.

(This Embodiment)

0120As shown in <figref idref="f0027">FIG. 27</figref>, the configuration of the MAC header in the embodiment is characterized in that the extension field exists at the top and whether or not MAC header exists can be determined by the value of the extension field. The feature that if only 72 bits are allocated for transmission, the necessity for using a plurality of MAC sub-headers is small is utilized and if MAC header exists, the extension field is always set to "0" and only one MAC sub-header is used. Therefore, if the extension field is set to "0," the reception party performs processing as MAC header exists and if the extension field is set to "1," the reception party assumes that MAC header does not exist and performs processing in RRC as RRC message. In RRC, the first two bits are used to identify the message. As a specific example, if the value of the first two bits "10," the message is RRC CONNECTION REQUEST and if the value is "11," the message is RRC CONNECTION RE-ESTABLISHMENT REQUEST.

0121In the system, the bit is the second bit of the MAC header, but not used as MAC and is a reserved bit. Thus, for extension in MAC in the future, the reserved bit can be used. Conversely, if an RRC message needs to be added, the bit can be used. Specifically, whether or not MAC header exists is not checked using the extension field only and when the extension field and the reserved bit corresponding to the first two bits of the MAC header are checked, if the value is "00," it is determined that no MAC header exists. Accordingly, the three values of "01," "10," and "11" can be used to indicate the RRC message. Thus, in the system, the extension field is used to identify the presence or absence of MAC header, whereby extension of MAC or addition of RRC message is made possible.

0122The operation of the terminal according to the embodiment will be described below with <figref idref="f0027">FIG. 28</figref>: At ST2801, the terminal checks the size allocated in Random Access Response. If the allocated size is larger than 72 bits, the process goes to ST2803. If 72 bits are allocated, the process goes to ST2804. At ST2804, the terminal determines whether call connection or reconnection is executed. That is, the terminal determines whether or not MAC header is used. To use MAC header, the process goes to ST2805; not to use MAC header, the process goes to ST2806. When the process goes to ST2805, if the terminal selects RACH preamble on its own (namely, Non-dedicated RACH preamble), the process goes to ST2806; if RACH preamble given from the base station is used, the process goes to ST2803.

0123At ST2803, the terminal uses MAC header as usual and creates transmission data. On the other hand, at ST2806, the terminal creates transmission data so that the first extension field of MAC header is set to "0." In <figref idref="f0028">FIG. 29</figref>, (c), (d), (e), and (f) show MAC header configuration examples at this time. <figref idref="f0029">FIG. 30</figref> shows a definition example of LCID.

0124In <figref idref="f0028">FIG. 29</figref>, (c) shows the case where only C-RNTI is transmitted. Here, 16 bits of 40 bits are used as C-RNTI and the remaining 24 bits are padding. Thus, LCID (11000 in <figref idref="f0029">FIG. 30</figref>) indicating that C-RNTI and padding are entered is entered.

0125In <figref idref="f0028">FIG. 29 (d)</figref>, C-RNTI and BSR are transmitted and LCID (11001 in <figref idref="f0029">FIG. 30</figref>) indicating that C-RNTI and BSR are entered is entered. This is used when BSR takes precedence over handover complete.

0126In <figref idref="f0028">FIG. 29 (e)</figref>, C-RNTI and DCCH (Dedicated Control Channel) is transmitted. Here, DCCH is a name as Logical channel of SRB described above and is separated into a plurality of DCCHs as SRB is separated into high priority SRB and low priority SRB. LCID can be defined as it indicates only that C-RNTI and high priority SRB are transmitted later; conversely, LCID can be defined as it indicates only that C-RNTI and low priority SRB are transmitted later, or both may be defined. <figref idref="f0029">FIG. 30</figref> shows an example wherein both are defined. LCID responsive to actually transmitted DCCH is set (11010 or 11011 in <figref idref="f0029">FIG. 30</figref>).

0127In <figref idref="f0028">FIG. 29 (f)</figref>, C-RNTI and CQI are transmitted. Thus, LCID (11100 in <figref idref="f0029">FIG. 30</figref>) indicating that C-RNTI and CQI are entered is entered.

0128At ST2807, the terminal transmits a message with no MAC header. Examples of transmission data at the time are shown by (a) and (b) in <figref idref="f0028">FIG. 29</figref> as the call connection time and reconnection time. Locations of information other than Message type may be different locations.

0129According to the operation of the embodiment, the range that can be defined as LCID is not used fruitlessly and it is made possible to ensure an area that can be used for Message type so that a new RRC message can be defined.

0130In the description given above, LCID is defined so as to combine C-RNTI and any other information by way of example, but any other method is also possible. If the terminal selects RACH preamble on its own, the base station can predict that the terminal enters C-RNTI in Message 3. Thus, if operation is predetermined so as to enter C-RNTI following MAC header whenever the terminal selects RACH preamble on its own, the need for defining LCID so as to combine C-RNTI and any other information is eliminated. Specifically, <figref idref="f0030">FIG. 31</figref> shows examples. In <figref idref="f0030">FIG. 31</figref>, (a) shows the case where only C-RNTI is entered and the remainder is padding. In this case, the terminal enters LCID indicating padding as LCID. If the terminal selects RACH preamble on its own, the base station understand that C-RNTI is always entered following MAC header and it is made possible for the base station to understand that RNTI comes following MAC header, followed by padding. Other cases are shown by (b), (c), and (d) in <figref idref="f0030">FIG. 31</figref>; the operation is similar and it is made possible for the base station to understand that C-RNTI exists and is followed by information indicated in LCID.

0131C-RNTI is entered just after MAC header by way of example, but can also be set in any other location.

Industrial Applicability

0132The invention can be used as a communication terminal, a base station, etc., that can assign priority to MAC control information and can control what information is to be transmitted as desired.