Source: https://patents.google.com/patent/JPWO2007148630A1/en
Timestamp: 2020-01-23 18:17:32
Document Index: 259120652

Matched Legal Cases: ['art 12', 'art 13', 'art 14', 'art 21', 'art 22', 'art 23', 'art 24', 'art 25', 'Application No. 2006']

JPWO2007148630A1 - Wireless communication apparatus and method used in mobile communication system - Google Patents
Wireless communication apparatus and method used in mobile communication system Download PDF
JPWO2007148630A1
JPWO2007148630A1 JP2008522436A JP2008522436A JPWO2007148630A1 JP WO2007148630 A1 JPWO2007148630 A1 JP WO2007148630A1 JP 2008522436 A JP2008522436 A JP 2008522436A JP 2008522436 A JP2008522436 A JP 2008522436A JP WO2007148630 A1 JPWO2007148630 A1 JP WO2007148630A1
JP2008522436A
2006-06-20 Priority to JP2006170704 priority Critical
2006-06-20 Priority to JP2006170704 priority
2007-06-15 Application filed by 株式会社エヌ・ティ・ティ・ドコモ filed Critical 株式会社エヌ・ティ・ティ・ドコモ
2007-06-15 Priority to PCT/JP2007/062159 priority patent/WO2007148630A1/en
2009-11-19 Publication of JPWO2007148630A1 publication Critical patent/JPWO2007148630A1/en
The wireless communication device having a retransmission control function determines, in the first sublayer, whether or not the error detection result received for the first packet is an affirmative response after transmitting the first packet to the communication partner. An error notification indicating that there is an error in the determination that the error detection result for the first packet is an affirmative response, a transmission unit that transmits the second packet following the first packet to the communication partner, From the first sublayer, a timer unit for waiting for a fixed period after transmission of the packet, and that the error detection result received for the first packet is an affirmative response when no error notification is reported within the fixed period. And a reporting unit that reports to the upper second sublayer.
The present invention relates to the technical field of mobile communication, and more particularly to a wireless communication apparatus and method used in a mobile communication system.
In this type of technical field, research and development related to next-generation mobile communication systems including radio access methods, retransmission control, handover, and the like are proceeding at a rapid pace.
FIG. 1 shows an example of a retransmission control procedure. The right side of the figure shows the operations of the medium access control (MAC) sublayer entity (Tx MAC) and the radio link control (RLC) sublayer entity (Tx RLC) on the transmission side. The left side of the figure shows the operations of the MAC sublayer entity (Rx MAC) and the RLC sublayer entity (Rx RLC) on the receiving side. In the downlink, the transmitter is a base station and the receiver is a user equipment. In the uplink, the transmitter is a user equipment and the receiver is a base station.
In steps S21 and S22, a packet to be transmitted is prepared. A packet to be transmitted is requested from the MAC sublayer to the RLC sublayer (new data request). In response to this request, a transmission packet is prepared in the MAC sublayer. In the illustrated example, a sequence number of “0” is given to this packet, that is, a packet data unit (PDU) (SN = 0).
As shown in step S11, the packet prepared on the transmission side is transmitted to the reception side. In this case, a packet data unit including user data specified by a sequence number (SN) is transmitted through a data channel, and includes user identification information (UE-ID), a process number (Proc), and a new data indicator (NDI: New Data Indicator) Other control information is transmitted on the control channel, and the system frame number (SFN) indicating the absolute transmission timing in the cell is broadcast on the broadcast channel.
The receiver that has received the control channel and the data channel together with the broadcast channel performs error detection on the received packet by, for example, cyclic redundancy check (CRC). The error detection result indicates negative (NACK) or positive (ACK). The former indicates that an error exceeding the allowable range has been detected, and the latter indicates the opposite. In the illustrated example, no error is detected or even if it is detected (CRC: OK).
As shown in step S12, the error detection result is reported to the transmission side. If an error is detected, a negative response is reported to the transmission side, and the transmission side identifies a packet related to the negative response and retransmits it. A packet transmitted from the transmission side is stored in a buffer (retransmission buffer) even after wireless transmission, and is discarded when a positive error detection result (ACK) is obtained. Therefore, if a negative error detection result is reported, the previously transmitted packet is identified accordingly and retransmitted.
In the illustrated example, an acknowledgment (ACK) is transmitted in step S12. Since the acknowledgment indicates that the packet has been received without error on the receiving side, the transmitting side may transmit the next packet. However, if it is later determined that the TxMAC judgment that the error detection result is an affirmative response is incorrect, it is difficult to retransmit a packet that was actually a negative response. This is because the packet is discarded after the TxRLC layer is reported as an affirmative response, and the window control is proceeding one after another.
In order to deal with such concerns, conventionally, after determining that the error detection result is an affirmative response in TxMAC, a timer was started and the error detection result was falsely recognized for a fixed period. Wait for the signal to notify. This notification may be referred to as a false ack indicator (FAI).
Thereafter, subsequent packet data is prepared as shown in steps S23 and S24, and wirelessly transmitted as shown in step S13. In the illustrated example, a packet with SN = 1 is wirelessly transmitted at the timing of SFN = 8 together with control information with Proc = 0 and NDI = 1.
When the FAI is not notified, it is confirmed by TxMAC that a predetermined period has elapsed as shown in “expiration of period” in FIG. Thus, it can be said that the determination that the error detection result is an affirmative response has become more accurate.
As shown in step S25, the upper layer (TxRLC) reports that the error detection result is an affirmative response. As a result, the report target packet (SN = 0) is discarded from the retransmission buffer, and window control proceeds. Such a technique is described in Non-Patent Document 1, for example.
R2-050907, "MAC functions: ARQ", Samsung.
FIG. 2 is a diagram for explaining the problems of the prior art. Even though the receiver returns a negative response, the transmitter misidentifies it as an acknowledgment. As described above, in order to confirm the authenticity of an affirmative response, a timer is started and it is monitored whether or not a predetermined period has elapsed. Subsequent packets that can be transmitted are transmitted one after another. The receiver refers to the process number (Proc), new data indicator (NDI), serial number (SN), etc., and considers the error detection results made in the past. Determine.
If the receiver returns a negative response but the transmitter misidentifies it as an acknowledgment, a new packet that is not a retransmission packet is transmitted to the receiver. As a result, the negative response returned previously is not properly processed, and the receiver can detect that the processing proceeds as an affirmative response.
In accordance with the error detection result, an indicator including the system frame number (SFN) of the packet to be retransmitted is created at the receiver and reported to the transmission side. What is to be retransmitted is a packet whose error detection result is a negative response, and is determined from the error detection result and SFN performed after step S11. The transmitter extracts the system frame number included in the reported indicator. The sequence number of the packet transmitted at the timing of the system frame number is stored on the transmission side. The sequence number of the packet to be retransmitted is specified from the system frame number reported in this way. The identified sequence number is reported to the TxRLC sublayer that manages the transmission packet (local NACK), and then the packet is retransmitted to the receiving side. In this way, even if erroneous recognition of the error detection result (ACK / NACK) occurs on the transmitter side, the receiving side can specify the packet to be retransmitted and appropriate retransmission control is performed.
The predetermined period after starting the timer should be set long enough for the above operation to be performed properly. If it is too short, a situation in which notification of ACK misauthorization cannot be received within a predetermined period occurs, which increases the possibility of packet loss and transmission quality degradation. As shown in FIG. 2, within a predetermined period, during the period T1 during which the next new data is wirelessly transmitted after an ACK error recognition has occurred, an ACK error such as FAI is detected after error detection at the receiver. A period T2 until transmission of the notification signal of authorization is started, and a period T3 required to transmit a notification signal of ACK error recognition such as FAI are included. In a system that schedules data transmission opportunities for different users on a shared data channel, the scheduling delay is expected to vary greatly depending on the number of users, the transmission rate required by each user, and the available radio bandwidth. Therefore, to be able to deal with all of these, the period T1 must be the longest period that can be expected. In the period of T2, considering that FAI is a very important signal, and the amount of information is small and the frequency of transmission is rare, transmission opportunities should be allocated preferentially (instantly). There is no change and it takes a short time. Although the period of T3 includes a radio transmission period, since a notification signal such as FAI has a small amount of information, it is not necessary to assume a large variation (for example, several tens of milliseconds may be used). From such a viewpoint, the predetermined period measured by the timer is set to be relatively long, particularly by the period T1.
If the predetermined period is such a long period, there is a concern that the packet cannot be discarded by TxRLC, the window control is delayed, and the throughput of the system is deteriorated.
An object of the present invention is to enhance a retransmission control function by optimizing a waiting time fixedly set using a timer.
According to the present invention, a wireless communication apparatus having a retransmission control function is used. The wireless communication apparatus transmits a first packet to a communication partner, and then determines whether or not an error detection result received for the first packet is an affirmative response in a first sublayer, and An error notification indicating that there is an error in the determination that the error detection result for the first packet is an affirmative response, and a transmission unit that transmits a second packet following one packet to the communication partner; A timer unit for waiting for a fixed period after transmission of the first packet, and indicating that the error detection result received for the first packet is an affirmative response when the error notification is not reported within the fixed period. And a reporting unit that reports to a second sublayer higher than one sublayer.
According to the present invention, it is possible to enhance the retransmission control function by optimizing the period of a fixed timer.
It is a flowchart which shows the operation | movement procedure for coping with the conventional ACK / NACK misidentification. It is a figure for demonstrating the conventional problem. 5 is a flowchart illustrating an operation procedure according to an embodiment of the present invention. FIG. 3 is a functional block diagram for an entity used in an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 11 Reception part 12 ACK / NAC determination part 13 Error detection part 14 FAI preparation part 21 New data request part 22 Transmission packet preparation part 23 Transmission part 24 FAI analysis part 25 Timer 31 Transmission buffer management part
FIG. 3 is a flowchart showing an operation procedure according to an embodiment of the present invention. The right half of FIG. 3 shows a medium access control (MAC) sublayer entity (Tx MAC) and a radio link control (RLC) sublayer entity (Tx RLC) on the transmission side. The left half of FIG. 3 shows a MAC sublayer entity (Rx MAC) and an RLC sublayer entity (Rx RLC) on the receiving side. In the downlink, the transmitter is a base station and the receiver is a user equipment. In the uplink, the transmitter is a user equipment and the receiver is a base station.
When the above information is received through the broadcast channel, the control channel, and the data channel, the receiver is not limited to the received packet, for example, an error such as a cyclic redundancy check (CRC). Perform detection. The error detection result indicates negative (NACK) or positive (ACK). The former indicates that an error exceeding a predetermined allowable range has been detected, and the latter indicates the opposite. In the illustrated example, an error may or may not be detected, and when the cyclic redundancy check method is successfully completed (CRC: OK), the procedure proceeds to the next step (S12).
In the illustrated example, an acknowledgment (ACK) is transmitted in step S12. Unlike the prior art described above, the timer is not started at this point.
Subsequent packet data is prepared as shown in steps S23 and S24, and wirelessly transmitted as shown in step S13. In the illustrated example, a packet with SN = 1 is wirelessly transmitted at the timing of SFN = 8 together with control information with Proc = 0 and NDI = 1.
Unlike the prior art, in this embodiment, a timer is started after the wireless transmission in step S13. The timer measures a predetermined period, which is shorter than the conventional predetermined period. This is because the predetermined period includes only the second period T2 and the third period T3 (FIG. 2) that vary only slightly, and includes the first period T1, which is the longest period that can be expected in consideration of large fluctuations. It is not necessary. When the predetermined period elapses without notification of FAI, the flow proceeds to step S25.
In step S25, a report indicating that the error detection result indicates an affirmative response is sent to the upper layer (TxRLC). As a result, the report target packet (SN = 0) is discarded from the retransmission buffer, and window control proceeds.
In the conventional method, the period from the error detection result report for the report target packet (SN = 0) in step S12 to the ACK report in step S25 is set to be fixedly long. For this reason, the period from the packet transmission in step S13 to the ACK report in step S25 greatly increases or decreases, and even if the scheduling delay of the next packet (SN = 1) from step S12 to step S13 is short, step S12 The period from the error detection report for the report target packet (SN = 0) to the ACK report in step S25 is unnecessarily extended, and it is necessary to wait until a certain period as a whole elapses. In this embodiment, when the scheduling delay of the next packet from step S12 to step S13 is short, the ACK report is promptly performed after a predetermined period after the short period. Even if the scheduling delay of the next packet becomes long, the timing at which the ACK report is made can be delayed as much as the conventional one.
FIG. 4 shows a functional block diagram for the entities used in one embodiment of the present invention. The operations shown in FIG. 2 are realized by the functional units of these entities. The receiving side RxMAC includes a receiving unit 11, an ACK / NACK determining unit 12, an error detecting unit 13, and an FAI creating unit 14. The TxMAC on the transmission side includes a new data request unit 21, a transmission packet creation unit 22, a transmission unit 23, a timer 25, and an FAI analysis unit 24. The transmission side TxRLC is provided with a transmission buffer management unit 31.
The receiving side 11 of the RxMAC on the receiving side receives the radio signal, extracts the signal addressed to itself, and transfers it to the subsequent processing element. Further, the RxMAC receiving unit 11 notifies the error detecting unit 13 of the process number (Proc), the value of the new data indicator (NDI) and the system frame number (SFN) associated with the received control channel addressed to the own device.
The ACK / NACK determination unit 12 performs error detection on the received signal. Error detection may be performed, for example, by the CRC method. The error detection result is reported not only to the error detection unit 13 but also to the transmission side.
The error detection unit 13 determines whether or not reception of the control channel has failed in the past. If it is determined that the failure has occurred, the FAI creation unit 14 is instructed to create the FAI.
The FAI creation unit 14 creates an indicator including the system frame number (SFN) of the recently received packet. The indicator is transmitted wirelessly.
The TxMAC new data request unit 21 of the transmitter receives an error detection result (ACK / NACK) report from the receiver. According to the report content, the transmission buffer management unit 31 is requested for data to be transmitted at the next transmission timing.
The transmission packet creation unit 22 creates a transmission packet for wirelessly transmitting data to be transmitted at the next transmission timing. The transmission packet constitutes a control channel and a data channel.
The transmission unit 23 transmits the created transmission packet.
The timer 25 measures a predetermined period after packet transmission. When the period expires, a notification to that effect is sent to the transmission buffer management unit 31.
The FAI analysis unit 24 receives the indicator created on the receiving side, and extracts the system frame number (SFN) included in the indicator. The extracted SFN is given to the transmission buffer management unit 31.
The transmission-side TxRLC transmission buffer management unit 31 accumulates packet data to be wirelessly transmitted in a buffer, extracts packet data as necessary, and sends the packet data to the transmission packet creation unit 22. The buffer stores not only packet data for initial transmission but also packet data for retransmission. The packet data for retransmission is stored together with attribute information associated therewith. If no FAI is notified during the predetermined period measured by the timer, the transmission buffer management unit 31 discards the packet indicated by the ACK report from the retransmission buffer.
This international application claims priority based on Japanese Patent Application No. 2006-170704 filed on June 20, 2006, the entire contents of which are incorporated herein by reference.
A wireless communication device having a retransmission control function,
A determination unit configured to receive an error detection result obtained for the first packet transmitted to the destination device and to determine whether the result is an acknowledgment in the first sublayer;
A transmitter configured to transmit a second packet following the first packet to the destination device;
A timer unit configured to time a certain period after transmission of the second packet;
When the message indicating that the error detection result is erroneously determined to be an acknowledgment is not received from the destination device within the predetermined period, the error detection result for the first packet is an acknowledgment. A reporting unit configured to report to the second sublayer higher than the first sublayer,
A method used in a wireless communication apparatus having a retransmission control function,
Transmitting a first packet to a destination device;
Receiving an error detection result for the first packet;
Determining whether the error detection result is an affirmative response in a first sublayer; and
Transmitting a second packet following the first packet to the destination device;
Measuring a certain period after transmitting the second packet;
When the message indicating that the error detection result is erroneously determined to be an acknowledgment is not received from the destination device within the predetermined period, the error detection result for the first packet is an acknowledgment. Reporting to the second sublayer higher than the first sublayer,
JP2008522436A 2006-06-20 2007-06-15 Wireless communication apparatus and method used in mobile communication system Pending JPWO2007148630A1 (en)
JP2006170704 2006-06-20
PCT/JP2007/062159 WO2007148630A1 (en) 2006-06-20 2007-06-15 Radio communication device and method used in mobile communication system
JPWO2007148630A1 true JPWO2007148630A1 (en) 2009-11-19
ID=38833372
JP2008522436A Pending JPWO2007148630A1 (en) 2006-06-20 2007-06-15 Wireless communication apparatus and method used in mobile communication system
US (1) US8140928B2 (en)
EP (1) EP2034763A1 (en)
JP (1) JPWO2007148630A1 (en)
KR (1) KR20090017699A (en)
CN (1) CN101502152A (en)
TW (1) TW200814602A (en)
WO (1) WO2007148630A1 (en)
JP2006170704A (en) 2004-12-14 2006-06-29 Mitsubishi Electric Corp Capacitance type acceleration detector
2007-06-15 KR KR1020097000504A patent/KR20090017699A/en not_active Application Discontinuation
2007-06-15 US US12/305,332 patent/US8140928B2/en not_active Expired - Fee Related
2007-06-15 WO PCT/JP2007/062159 patent/WO2007148630A1/en active Application Filing
2007-06-15 CN CN 200780028945 patent/CN101502152A/en not_active Application Discontinuation
2007-06-15 JP JP2008522436A patent/JPWO2007148630A1/en active Pending
2007-06-15 EP EP07745413A patent/EP2034763A1/en not_active Withdrawn
2007-06-20 TW TW096122045A patent/TW200814602A/en unknown
WO2007148630A1 (en) 2007-12-27
EP2034763A1 (en) 2009-03-11
US20100293427A1 (en) 2010-11-18
US8140928B2 (en) 2012-03-20
KR20090017699A (en) 2009-02-18
TW200814602A (en) 2008-03-16
CN101502152A (en) 2009-08-05
JP2014222901A (en) 2014-11-27 Method and apparatus for quick retransmission of signals in communication system
JP2012217185A (en) 2012-11-08 Radio resource control (rrc) - service data unit reception
JP2004500769A (en) 2004-01-08 Access investigation and verification with collision detection
JP2006506915A (en) 2006-02-23 Use of idle frames for early transmission of negative acknowledgment of frame reception