JP2018110275A - Wireless terminal, communication method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of realizing power saving of a wireless terminal while quickly receiving a signal from the network side.SOLUTION: The present invention is related to a wireless terminal that includes communication processing means for sending and receiving data and communication control means that starts reception at a predetermined timing of a non-reception period of a second period in a time period in which the communication processing means performs intermittent reception of the second period longer than a first period and causes the communication processing means to perform reception by any number of times.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless terminal, a communication method, and a program.

  In 3GPP LTE (Long Term Evolution), which is one of the next generation cellular systems, in order to reduce the power consumption of the wireless terminal, a function of intermittent reception (DRX) is supported (non-patented). References 1, 2). In LTE, a period composed of a reception period (On-Duration) called DRX cycle and a subsequent non-reception period (Opportunity for DRX) is defined, and DRX is realized by repeating these periods.

  The wireless terminal needs to always receive a downlink control channel (PDCCH) in On-duration, and does not have to receive PDCCH in Opportunity for DRX. If the wireless terminal fails to receive data during the On-Duration period and the data is retransmitted after the On-Duration period, the period for receiving the PDCCH is extended.

  Here, a period in which a wireless terminal in DRX operation receives the PDCCH is referred to as Active Time, and On-Duration is the minimum value of Active Time. Furthermore, for each wireless terminal, two DRX states (levels) “ShortDRX” and “LongDRX” having different lengths of Opportunity for DRX can be set. In LTE, when a wireless terminal in the Short DRX state does not receive data for a certain period, DRX state control (DRX state control) for transitioning to the Long DRX state is performed. In addition, a timer (drxShortCycleTimer) is used for determination of state transition from ShortDRX to LongDRX. Thereby, the DRX state (level) suitable for the data reception frequency of the wireless terminal can be set, and the power consumption of the wireless terminal can be reduced.

3GPP TS36.300v900 (Internet <URL> http: www.3gpp.org/ftp/Specs/html-info/36300.html) 3GPP TS36.321v860 (Internet <URL> http: www.3gpp.org/ftp/Specs/html-info/36321.html)

  However, in the case of intermittent reception with a long interval between Active Time and Active Time, such as LongDRX, even if a paging signal from the network side arrives during that period, the wireless terminal performs paging until it reaches Active Time. There was a problem that signals could not be received.

  Accordingly, the present invention has been invented in view of the above problems, and it is an object of the present invention to provide a wireless terminal capable of realizing power saving of the wireless terminal while rapidly receiving a signal from the network side.

  The present invention provides a communication processing means for transmitting and receiving data, and a predetermined non-reception period of the second period during the intermittent reception operation of the second period having a period longer than the first period. And a communication control unit that causes the communication processing unit to receive an arbitrary number of times.

  The present invention starts reception at a predetermined timing in the non-reception period of the second cycle during the intermittent reception operation of the second cycle having a period longer than the first cycle, and performs an arbitrary number of receptions. It is a communication method.

  In the present invention, the communication processing means for transmitting and receiving data starts reception at a predetermined timing in the non-reception period of the second cycle during the intermittent reception operation of the second cycle having a period longer than the first cycle. And a program for causing a computer to execute a communication control process for causing the communication processing means to receive an arbitrary number of times.

  According to the present invention, it is possible to realize power saving of a wireless terminal while rapidly receiving a signal from the network side.

FIG. 1 is a block diagram of the present invention. FIG. 2 is a diagram illustrating an example of a schematic configuration of the wireless communication system according to the embodiment of this invention. FIG. 3 is a block diagram of the radio terminal (UE) 1 in the radio communication system of the present embodiment. FIG. 4 is a block diagram of the radio base station (eNB) 20 of the present embodiment. FIG. 5 is a diagram illustrating an operation of discontinuous reception (DRX: Discontinuous Reception) of a wireless terminal in the wireless communication system of the present embodiment. FIG. 6 is a diagram illustrating a case in which two Wake ups are provided at a constant cycle and performed every one cycle interval of LongDRX within a Long DRX Sleep period. FIG. 7 is a diagram illustrating a case in which two Wake ups are provided at a constant cycle and performed at every cycle interval of LongDRX within the Long DRX Sleep period, at the Wake up timing of Short DRX. FIG. 8 is a diagram illustrating a case where a wake up is provided once at a timing near the center of the Long DRX. FIG. 9 is a diagram illustrating a case where the LongDRX timing is reset after wake up. FIG. 10 is a flowchart of the operation after Wake up performed during the Sleep period of LongDRX. FIG. 11 is a diagram illustrating a case where data is received during ShortDRX and transition is made from LongDRX to ShortDRX.

  An outline of the present invention will be described. FIG. 1 is a block diagram of the present invention.

  As shown in FIG. 1, the present invention includes a communication processing unit 1 that transmits and receives data, and a second period when the communication processing unit 1 performs an intermittent reception operation of a second period that is longer than the first period. The wireless terminal includes a communication control unit 2 that starts reception at a predetermined timing in the non-reception period and causes the communication processing unit 1 to receive an arbitrary number of times.

  In other words, the present invention relates to a period in which data can be received (for example, Active Time) and a period in which the period is long and the wireless terminal is operating for intermittent reception (for example, LongDRX). In the operation, the reception operation is performed for a certain period at a predetermined timing in the non-reception period and in a cycle shorter than the second cycle.

  Here, there is ShortDRX as a representative of the first period, and LongDRX as a representative of the second period.

  Further, the predetermined timing of the non-reception period of the second cycle may be an arbitrary timing or a predetermined timing. Examples of the predetermined timing include the timing of the synchronized first cycle and the timing at which the non-reception period of the second cycle is constant before and after the timing (for example, the non-reception period of the second cycle). Timing near the center of the).

  In addition, the number of reception operations in the non-reception period of the second cycle (the number of times of activation), the reception operation may be performed only once in the non-reception period of the second cycle, or may be performed multiple times. Also good. However, when it is performed a plurality of times, the reception operation is performed at a cycle shorter than the second cycle. Further, when performing a plurality of times, it is preferable that the non-reception period of the second period is constant before and after the reception operation, for example, the non-reception period of the second period before and after the timing, for example. In the case of performing the reception operation twice, the reception operation is performed in such a cycle that becomes active at a timing near one third or two thirds of the non-reception period of the second cycle.

  Furthermore, although it is the reception operation of the non-reception period of the second cycle, the reception operation may be performed only for one non-reception period of the second cycle, or the non-reception period of the second cycle is constant. The reception operation may be performed at every interval.

  In addition, after the reception operation in the non-reception period of the second cycle, the intermittent reception operation may be performed while maintaining the timing of the second cycle, or the timing of the second cycle is reset, The intermittent reception operation of the second cycle may be performed at a proper timing. Furthermore, when data is received during the reception operation in the non-reception period of the second cycle, the intermittent reception operation may be performed by transitioning to the first cycle with a shorter cycle.

  Further, in determining whether or not to perform the reception operation in the non-reception period of the second cycle, the second cycle takes into account the past received data performance (for example, the amount of data and the presence or absence of the most recent data reception). It may be determined whether or not to perform the reception operation during the non-reception period.

  According to the present invention, power saving of a wireless terminal can be realized while quickly receiving a paging signal from the network side.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiment, “3GPP LTE (Long Term Evolution)” is assumed as a wireless communication system (cellular system).

  FIG. 2 is a diagram illustrating an example of a schematic configuration of the wireless communication system according to the embodiment of this invention.

  The radio communication system according to the present embodiment includes a radio terminal (UE: User Equipment) UE10 and a radio base station (eNB: evolved NodeB) eNB20. Here, the UE 10 has completed connection establishment (RRC Connection) for communicating with the eNB 20. Also, CC1 to CC3 are assigned as component carriers (CC) capable of carrier aggregation (CA), and CC1 to CC3 are already in a state where data can be received simultaneously.

  CC1 to CC3 may be either continuous or discontinuous, and the frequency bands may be the same or different. Further, the eNB 20 notifies the UE 10 of a parameter of intermittent reception (DRX: Discontinuous Reception), and the UE 10 performs necessary setting (for example, setting of an expiration value of a DRX related timer) according to the parameter. At this time, the DRX parameters are common in CC1 to CC3.

  FIG. 3 is a block diagram of the radio terminal (UE) 10 in the radio communication system according to the present embodiment.

  In FIG. 3, the UE 10 includes a receiver 11, a transmitter 12, a signal processing unit 13, and a communication control unit 14.

  Each of the receiver 11 and the transmitter 12 is a part that receives and transmits a radio signal with the eNB 20. The signal processing unit 13 is a part that generates a radio signal for transmitting certain information to the eNB 20 and restores the original information from the received radio signal. The communication control unit 14 is a part that instructs the signal processing unit 13 to generate a transmission signal, restore information, and the like, and the DRX control of the UE is also managed by the communication control unit 14.

  FIG. 4 is a block diagram of the radio base station (eNB) 20 of the present embodiment.

  In FIG. 4, the eNB 20 includes a receiver 21, a transmitter 22, a signal processing unit 23, a communication control unit 24, and a terminal management unit 25. The receiver 21, transmitter 22, signal processing unit 23, and communication control unit 24 basically have the same functions as those of the UE 10. Moreover, in the terminal management part 25, it manages individually with respect to each of several UE.

  FIG. 5 is a diagram illustrating an operation of discontinuous reception (DRX: Discontinuous Reception) of a wireless terminal in the wireless communication system of the present embodiment.

  First, as shown in FIG. 5, the DRX cycle, which is a period of intermittent reception, receives a PDCCH during a period (On-Duration) in which the downlink control channel PDCCH (Physical Downlink Control Channel) must be continuously received. It may be composed of a period (Opportunity for DRX). The former is also called a Wake up period, and the latter is also called a Sleep period. The latter may be a period in which no PDCCH is received or a period in which no PDCCH should be received.

  The data is transmitted by PDSCH (Physical Downlink Shared Channel), and PDSCH scheduling information is included in PDCCH. Therefore, after receiving the PDCCH and detecting the scheduling information, the designated data can be received.

  There are two types of DRX cycle: ShortDRX and LongDRX. ShortDRX and LongDRX have the same On-Duration, the lengths of periods in which PDCCHs other than On-Duration need not be received are different, and Short-DRX is set to have a shorter On-Duration interval. In LTE, there is a restriction that Long DRX is an integral multiple of Short DRX. The length of the On-Duration and DRX cycle, for example, On-Duration can be set in a dozen ways from 1 ms to 200 ms, and the DRX cycle can be set from 2 ms (Short DRX minimum) to 2560 ms (Long DRX maximum), Dozens of settings are possible for ShortDRX and LongDRX.

  Thus, DRX has two DRX states called ShortDRX and LongDRX. ShortDRX corresponds to the first period in the present invention, and LongDRX corresponds to the second period in the present invention.

  Basically, starting from ShortDRX, if no data is received for a certain period of time, transition is made to LongDRX.

  Next, in the present embodiment, the communication control unit 14 performs control so that the Wake up period is provided at a predetermined timing of the Long DRX Sleep period and at a period shorter than the Long DRX period. In this example, an example of carrier aggregation (CA) has been described. However, since the same processing can be performed for each of CC1 to CC3, the following description focuses on CC1.

  First, although the communication control unit 14 wakes up and the number of times during the Sleep period of LongDRX, the following control can be considered.

(1) Controlling to Wake Up Randomly During Long DRX Sleep Period First, there is a method of controlling to wake up at random timing within the Sleep period of Long DRX. The number of Wake ups may be one time within the Long DRX Sleep period or a plurality of times in a predetermined cycle. FIG. 6 shows a case where two Wake ups are provided at a fixed cycle and at a certain cycle within the Long DRX Sleep period, and this operation is performed at each cycle interval of the Long DRX.

(2) Method of controlling to wake up at a predetermined timing within the Sleep period of LongDRX A method of controlling the timing by matching with the Wake up of ShortDRX is conceivable. FIG. 7 shows a case where two Wake ups are provided at a constant cycle at a Short DRX Wake up timing within a Long DRX Sleep period, and this operation is performed at each cycle interval of the Long DRX. .

(3) A method for controlling Wake up at the timing when the Long DRX Sleep period is constant before and after the Wake up. . FIG. 8 is an example in which a Wake up is provided once at the timing near the center of the Long DRX cycle, and shows a case where the Sleep period of the Long DRX is constant before and after the Wake up period.

  The operation at the above timing is not necessarily limited to one, and may be controlled by combining these methods.

  Next, the control of the operation after Wake up performed during the Sleep period of LongDRX will be described.

  The operation after Wake up performed during the Sleep period of LongDRX. (1) After Long Wake up, Long DRX is continued while maintaining the Long DRX timing and period. (2) After Wake up, Long DRX timing is reset. For example, there is a method of continuing LongDRX at a period of LongDRX. FIG. 9 shows a case where the LongDRX timing is reset after Wake up and the LongDRX is continued in the LongDRX cycle.

  Further, the subsequent operation may be determined depending on whether or not data is received during the Wake up performed during the Sleep period of the LongDRX.

  FIG. 10 is a flowchart of the operation after Wake up performed in the above-described Long DRX Sleep period.

  First, the ShortDRX is operated during the Sleep period of the LongDRX. It is determined whether data is received during this ShortDRX. When data is received, the transition is from Long DRX to Short DRX. On the other hand, when data is not received, the operation of the Long DRX is continued at the timing of the old Long DRX or the new Long DRX.

  Here, FIG. 11 is a diagram illustrating a case where the ShortDRX is operated during the Sleep period of the LongDRX, data is received during the ShortDRX, and a transition is made from the LongDRX to the ShortDRX.

  In determining whether or not to wake up during the Long DRX sleep period, the past received data performance (for example, the amount of data and the presence or absence of the most recent data reception) may be considered. For example, if the data reception amount at the time of ShortDRX before the transition to LongDRX exceeds a predetermined threshold, Wake up is performed during the Sleep period of LongDRX. When data is received during the short DRX of the last several cycles before the transition to LongDRX, Wake up is performed during the Sleep period of LongDRX.

  In such a case, there is a high possibility that data will be transmitted during the Long DRX period, and by wake-up during the Long DRX sleep period, it is possible to reduce the power consumption of the wireless terminal while quickly receiving a signal from the network side. realizable.

  In the above-described embodiment, each unit is configured by hardware, but may be configured by a program that causes the information processing apparatus (CPU) to perform the above-described operation processing.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea.

1 Communication Processing Unit 2 Communication Control Unit 10 UE
20 eNB
DESCRIPTION OF SYMBOLS 11 Receiver 12 Transmitter 13 Signal processing part 14 Communication control part 21 Receiver 22 Transmitter 23 Signal processing part 24 Communication control part 25 Terminal management part

Claims (17)

Communication processing means for transmitting and receiving data; and
During the operation of intermittent reception of the second cycle having a period longer than the first cycle, the communication processing means starts reception at a predetermined timing in the non-reception period of the second cycle, and receives an arbitrary number of times. A wireless terminal having communication control means for causing the communication processing means to perform. 2. The wireless terminal according to claim 1, wherein the communication control unit causes the communication processing unit to start a data reception operation at the timing of the first cycle in the non-reception period of the second cycle. The wireless terminal according to claim 1, wherein the communication control unit causes the communication processing unit to perform a data reception operation for a certain period in the first cycle. The communication control unit causes the communication processing unit to perform a data reception operation for a certain period at a timing such that the non-reception period of the second period is equal before and after the data reception operation. The wireless terminal according to claim 3. When the communication control unit receives data during the data reception operation performed during the non-reception period of the second period by the communication processing unit, the communication control unit performs the intermittent reception operation of the communication processing unit. The wireless terminal according to any one of claims 1 to 4, wherein a transition is made from a period of 2 to the first period. After the data reception operation performed during the non-reception period of the second cycle by the communication processing unit, the control unit maintains the timing of the second cycle and performs the intermittent reception operation on the communication processing unit. The wireless terminal according to any one of claims 1 to 5, wherein the wireless terminal is performed. The control means resets the timing of the second cycle after the data receiving operation performed during the non-reception period of the second cycle by the communication processing means, and resets the timing of the second cycle at a new timing. The wireless terminal according to any one of claims 1 to 5, wherein the communication processing unit performs an intermittent reception operation. Based on the past data transmission / reception results, the control means is configured to execute the second processing at a predetermined timing of the non-reception period of the second period while the communication processing means is performing the intermittent reception operation of the second period. 8. The wireless terminal according to claim 1, wherein it is determined whether or not the data reception operation is performed for a certain period with a period shorter than the period. A communication method in which reception is started at a predetermined timing in a non-reception period of the second cycle and reception is performed an arbitrary number of times during the intermittent reception operation of the second cycle having a cycle longer than the first cycle. The communication method according to claim 9, wherein the data reception operation is started at the timing of the first cycle in the non-reception period of the second cycle. 11. The communication method according to claim 9, wherein the data reception operation is performed for a certain period of time in the first period in the non-reception period of the second period. The communication according to any one of claims 9 to 11, wherein the data reception operation is performed for a certain period of time at a timing such that the non-reception period of the second period is equal before and after the data reception operation. Method. When data is received during the data reception operation performed during the non-reception period of the second cycle, the intermittent reception operation of the second cycle is changed to the intermittent reception operation of the first cycle. The communication method according to any one of claims 9 to 12. The communication according to any one of claims 9 to 13, wherein after the data reception operation performed during the non-reception period of the second cycle, the operation of intermittent reception is performed while maintaining the timing of the second cycle. Method. 10. From the data reception operation performed during the non-reception period of the second cycle, the timing of the second cycle is reset and the intermittent reception operation of the second cycle is performed at a new timing. The communication method according to claim 13. Based on the past data transmission / reception results, during the intermittent reception operation of the second cycle, at a predetermined timing of the non-reception period of the second cycle, for a certain period of time shorter than the second cycle, The communication method according to claim 9, wherein it is determined whether to perform a data reception operation. The communication processing means for transmitting and receiving data starts reception at a predetermined timing of the non-reception period of the second cycle during the operation of intermittent reception of the second cycle having a period longer than the first cycle, A program for causing a computer to execute communication control processing for causing the communication processing means to receive the number of times.