Power saving method for monitoring data channels

Abstract

A power saving method of monitoring a data channel and a user equipment (UE) are presented. A network node can indicate to a UE that the UE can enter a power saving mode by sending a DCI to the UE. The DCI can indicate a power saving duration and an additional monitoring duration. The power saving duration can indicate a length of the power saving mode and a start point and an end point of the power saving mode. The additional monitoring duration can indicate that the UE needs to perform monitoring for a period of time before the power saving mode based on the first power saving duration indicated by the DCI.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 63 / 165,750, filed March 25, 2021, entitled “Condition-Based Power Saving Enhancements,” the subject matter of which is incorporated by reference into the application. TECHNICAL FIELD

[0003] The disclosed embodiments relate generally to wireless communications, and more specifically, to power saving methods for monitoring data channels. BACKGROUND

[0004] Wireless communication networks have grown exponentially over the years. Long-term evolution (LTE) systems provide high peak data rates, low latency, improved system capacity, and low operating costs due to simplified network architecture. LTE systems, also known as 4G systems, also provide seamless integration with older wireless networks, such as GSM, CDMA, and universal mobile telecommunication system (UMTS). In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNodeBs / eNBs) that communicate with multiple mobile stations known as user equipment (UE). Third generation partnership project (3GPP) networks typically include a mix of 2G / 3G / 4G systems. The next generation mobile network (NGMN) board has decided to focus future NGMN activities on defining end-to-end requirements for the 5G new radio (NR) system.

[0005] In conventional techniques, a network node can indicate to a UE that the UE can enter a power saving mode by sending a DCI to the UE. However, if the data scheduled by the DCI is not successfully decoded by the UE, the UE can still enter the DCI-based power saving mode directly.

[0006] A solution is sought. SUMMARY

[0007] A power saving method for monitoring data channels is presented. A network node can indicate to a UE that the UE can enter a power saving mode by sending a downlink control information (DCI) to the UE. The DCI can indicate a power saving duration and an additional monitoring duration. The power saving duration can indicate a length of the power saving mode and a start and end point of the power saving mode. The additional monitoring duration can indicate a period of time that the UE needs to perform monitoring before the power saving mode based on the first power saving duration indicated in the DCI.

[0008] In one embodiment, a UE receives a first DCI from a network node, where the first DCI indicates a first power saving duration and a first additional monitoring duration. The UE determines whether data in the first DCI is successfully decoded by the UE. In a case that the data scheduled by the first DCI is not successfully decoded, the UE performs monitoring for a period of time based on the first additional monitoring duration before a power saving mode based on the first power saving duration.

[0009] According to the power saving method for monitoring data channels and the user equipment provided by the present application, in a case that data scheduled by a DCI is not successfully decoded, a configured duration can be triggered to handle possible retransmission scheduling.

[0010] Other embodiments and advantages are described in the following detailed description. This summary is not intended to define the application. The application is defined by the claims. BRIEF DESCRIPTION OF DRAWINGS

[0011] The accompanying drawings illustrate embodiments of the application, wherein like numbers refer to like components.

[0012] Figure 1 is a simplified block diagram of a network node and a user equipment that perform certain embodiments of the application.

[0013] Figure 2A illustrates an example of a power saving duration and an additional monitoring duration.

[0014] Figure 2B illustrates another example of a power saving duration and an additional monitoring duration.

[0015] Figure 3 illustrates an example of two specific DCIs with different types.

[0016] Figure 4 illustrates another example of two specific DCIs with different types.

[0017] Figure 5 illustrates an example of an additional monitoring duration and an additional power saving duration.

[0018] Figure 6 is a flowchart of a power saving method for monitoring a data channel according to a novel aspect. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to some embodiments of the application, examples of which are illustrated in the accompanying drawings.

[0020] Figure 1 is a simplified block diagram of a network node and a user equipment (UE) that perform some embodiments of the application. The network node 101 can be a base station (BS) or a gNB, but the application should not be limited thereto. The UE 102 can be a smartphone, a wearable device, an Internet of Things (IoT) device, and a tablet computer, etc. Alternatively, the UE 110 can be a notebook (NB) or a personal computer (PC) inserted or installed with a data card, including a modem and one or more radio frequency transceivers, to provide wireless communication functions.

[0021] The network node 101 has an antenna array 111 with multiple antenna elements that transmit and receive radio signals, one or more RF transceiver modules 112 coupled with the antenna array that receive RF signals from the antenna 111, convert the RF signals to baseband signals, and send the baseband signals to the processor 113. The RF transceiver 112 also converts baseband signals received from the processor 113 to RF signals and sends them to the antenna 111. The processor 113 processes the received baseband signals and invokes different functional modules and circuits 120 to perform the features of the network node 101. The memory 114 includes non-volatile computer readable storage media and volatile computer readable storage media that store program instructions and data 115 to control the operation of the network node 101. The network node 101 also includes a plurality of functional modules that perform different tasks according to embodiments of the application.

[0022] Similarly, the UE 102 has an antenna 131 for transmitting and receiving radio signals. An RF transceiver 132 coupled with the antenna 131 receives RF signals from the antenna 131, converts the RF signals to baseband signals, and sends the baseband signals to a processor 133. The RF transceiver 132 also converts baseband signals received from the processor 133 to RF signals and sends the RF signals to the antenna 131. The processor 133 processes the received baseband signals and invokes different functional modules and circuits 140 to perform features in the UE 102. The memory 134 includes non-volatile and volatile computer readable storage media, storing program instructions and data 135 to control the operation of the UE 102. The UE 102 also includes a plurality of functional modules and circuits to perform different tasks according to embodiments of the present application.

[0023] The functional modules and circuits 120 and 140 can be implemented and configured through hardware, firmware, software, and any combination thereof. The functional modules and circuits 120 and 140, when executed by the processors 113 and 133 (e.g., by executing program codes 115 and 135), allow the network node 101 and the UE 102 to perform embodiments of the present application.

[0024] In an example of the present application, Figure 1 In an example of the present application, the network node 101 can include an allocation circuit 121 and a downlink control information (DCI) transmission circuit 122. The allocation circuit 121 can send normal DCI to the UE 102 or send special DCI to the UE 102. The DCI transmission circuit 122 can send normal DCI or special DCI to the UE 102. According to one novel aspect, the special DCI is considered as DCI indicating PDCCH monitoring adaptation and DCI associated with additional monitoring duration compared to the normal DCI.

[0025] Similarly, the UE 102 can include a determination circuit 141, a monitoring circuit 142, and a mode selection circuit 143. The determination circuit 141 can determine whether data in the DCI is successfully decoded. The monitoring circuit 142 can monitor a data channel, such as a physical downlink control channel (PDCCH). The mode selection circuit 143 can determine to enter a power saving mode based on the DCI.

[0026] According to one novel aspect, the network node 101 can indicate that the UE 102 can enter the power saving mode by sending a specific DCI to the UE 102. According to one novel aspect, the specific DCI can indicate a power saving duration and an additional monitoring duration. The power saving duration can indicate the length of the power saving mode and the start and end point of the power saving mode. The start point of the power saving mode is the slot in which the UE 102 receives the specific DCI. In an embodiment, the power saving duration can be a continuous duration. In another embodiment, the power saving duration can comprise several periodic durations. The additional monitoring duration can indicate that the UE 102 needs to perform monitoring for a period of time before the power saving mode based on the power saving duration indicated in the specific DCI.

[0027] According to one novel aspect, when the UE 102 receives the specific DCI from the network node 101, the UE 102 can determine whether the specific DCI is successfully decoded, e.g. whether the HARQ process result is valid. In one embodiment, for downlink transmission, when the HARQ process result is valid, the UE 102 can send a HARQ ACK to the network node 101. That is, when the UE 102 sends the HARQ ACK to the network node 101, the UE 102 can determine that the specific DCI is successfully decoded.

[0028] In case the data scheduled by the specific DCI is not successfully decoded (e.g. the HARQ process result is not valid), the UE 102 can need to perform monitoring on the data channel (e.g. PDCCH) for a period of time based on the additional monitoring duration indicated in the specific DCI. During the additional monitoring duration, the UE 102 can determine whether the network node 101 schedules a new indication (e.g. a new DCI). If the UE 102 receives the new indication from the network node 101 during the additional monitoring duration, the UE 102 can perform the following operations based on the information of the new indication. If the UE 102 does not receive the new indication from the network node 101 during the additional monitoring duration, the UE 102 can enter the power saving mode based on the power saving duration indicated in the specific DCI. According to another novel aspect, when the HARQ process result is unknown or uncertain (e.g. for uplink transmission), the UE 102 can also need to perform monitoring on the data channel (e.g. PDCCH) for a period of time based on the additional monitoring duration indicated in the specific DCI.

[0029] According to one novel aspect, an additional monitoring duration can be counted by a timer. When the timer has expired and the UE 102 has not received a new indication from the network node 101, the UE 102 can enter the power saving mode based on the power saving duration indicated in the specific DCI.

[0030] In case the data scheduled by the specific DCI is successfully decoded (e.g. HARQ process result valid), the UE 102 can enter the power saving mode based on the power saving duration indicated in the specific DCI.

[0031] Figure 2A An example of power saving duration and additional monitoring duration is illustrated. As Figure 2A shown, if the data scheduled by the specific DCI (i.e. DCI indicates PDCCH monitoring adaptation) is successfully decoded (e.g. HARQ process result valid), the UE 102 can enter the power saving mode based on the power saving duration indicated in the specific DCI. If the specific DCI is not successfully decoded (e.g. HARQ process result invalid), the UE 102 can need to perform data channel (e.g. PDCCH) monitoring for a period based on the additional monitoring duration indicated in the specific DCI before the UE 102 enters the power saving mode based on the power saving duration indicated in the specific DCI. Figure 2B Another example of power saving duration and additional monitoring duration is illustrated. As Figure 2B shown, the UE first enters the power saving mode. If the specific DCI is not successfully decoded (e.g. HARQ process result invalid), the UE 102 can need to perform data channel (e.g. PDCCH) monitoring for a period based on the additional monitoring duration indicated in the specific DCI. Then, the UE 102 can enter the power saving mode based on the power saving duration indicated in the specific DCI.

[0032] According to one novel aspect, the UE 102 can receive two specific DCIs (e.g., a first specific DCI and a second specific DCI) with different types, respectively. In one example, the first specific DCI is for uplink transmission (e.g., UL grant) and the second specific DCI is for downlink transmission (e.g., DL grant). In another example, the first specific DCI is for downlink transmission (e.g., DL grant) and the second specific DCI is for uplink transmission (e.g., UL grant). The first specific DCI can indicate a first power saving duration and a first additional monitoring duration, and the second specific DCI can indicate a second power saving duration and a second additional monitoring duration. The first additional monitoring duration and the second additional monitoring duration are configured based on the same configuration rule. For downlink transmission, the additional monitoring duration (e.g., the first additional monitoring duration and the second additional monitoring duration) can be configured as a sum of a drx-HARQ-RTT-TimerDL duration and a drx-RetransmissionTimerDL duration. The UE 102 can not need to perform monitoring during the portion of time corresponding to the drx-HARQ-RTT-TimerDL duration. For uplink transmission, the additional monitoring duration (e.g., the first additional monitoring duration and the second additional monitoring duration) can be configured as a sum of a drx-HARQ-RTT-TimerUL duration and a drx-RetransmissionTimerUL duration. The UE 102 can not need to perform monitoring during the portion of time corresponding to the drx-HARQ-RTT-TimerUL duration.

[0033] According to one embodiment, when the UE 102 receives two specific DCIs (e.g., a first specific DCI and a second specific DCI) with different types, respectively, the UE 102 can determine the duration of the power saving mode based on the overlapping duration of the first power saving duration and the second power saving duration. Figure 3 An example of two specific DCIs with different types is illustrated. The UE 102 receives a first specific DCI. The first specific DCI can indicate a first power saving duration from PSD start，1 to PSD end，1 . Then, the UE 102 receives a second specific DCI before entering the power saving mode based on the first power saving duration. The second specific DCI can indicate a second power saving duration from PSD start，2 to PSD end，2 . Thus, the UE 102 can determine the duration of the power saving mode based on the overlapping duration of the first power saving duration and the second power saving duration. That is, the duration of the power saving mode is from PSD start,2to PSD end,1 .

[0034] According to another embodiment, when the UE 102 can receive two specific DCIs with different types (e.g., a first specific DCI (i.e., an early specific DCI) and a second specific DCI (i.e., a late specific DCI)) respectively, the UE 102 can determine the duration of the power saving mode based on the second power saving duration indicated by the latest specific DCI (i.e., the second specific DCI). Figure 4 Another example with two specific DCIs with different types is illustrated. The UE 102 receives a first specific DCI (i.e., an early specific DCI). The first specific DCI can indicate a first power saving duration from PSD start,1 to PSD end,1 . Then, the UE 102 receives a second specific DCI (i.e., a late specific DCI) before entering the power saving mode based on the first power saving duration. The second specific DCI can indicate a second power saving duration from PSD start，2 to PSD end,2 . Thus, the UE 102 can determine the duration of the power saving mode based on the second power saving duration indicated by the latest specific DCI (i.e., the second specific DCI). That is, the duration of the power saving mode is from PSD start,2 to PSD end,2 .

[0035] According to one novel aspect, the UE 102 can remain in the power saving mode until an indication to leave the power saving mode is received from the network node 101, or the UE can leave the power saving mode after the power saving duration indicated by the specific DCI expires. According to one novel aspect, if connected Discontinuous Reception (c-DRX) is configured by the network node 101, the UE 102 can be configured to return to the data channel monitoring mode at the beginning of each long cycle.

[0036] According to one novel aspect, the UE 102 can maintain the power saving mode for a period of time based on an additional power saving duration before leaving the power saving mode. According to one novel aspect, the additional power saving duration can be longer than the additional monitoring duration. In one embodiment, the additional power saving duration is obtained based on the additional monitoring duration. For example, the length of the additional power saving duration can be the additional monitoring duration plus a time unit, where the time unit can be a symbol, a slot, etc. In another embodiment, the additional power saving duration is indicated in the DCI. Figure 5An example of additional monitoring duration and additional power saving duration is illustrated. The network node 101 can send a specific DCI to the UE 102 for entering the power saving mode and send a specific DCI to the UE 102 for leaving the power saving mode. The length of the additional power saving duration indicated in the specific DCI for leaving the power saving mode can be longer than the additional monitoring duration indicated in the specific DCI for entering the power saving mode.

[0037] Figure 6 A flowchart of a power saving method for monitoring a data channel according to one novel aspect is illustrated. In step 601, the UE 102 receives a first DCI from the network node 101, where the first DCI indicates a first power saving duration and a first additional monitoring duration. In step 602, the UE 102 determines whether the data in the first DCI is successfully decoded.

[0038] In step 603, if it is determined that the data scheduled by the first DCI is not successfully decoded, the UE 102 performs monitoring for a period of time based on the first additional monitoring duration before entering a power saving mode based on the first power saving duration. In step 604, if the data scheduled by the first DCI is successfully decoded, the UE 102 enters the power saving mode based on the first power saving duration.

[0039] According to one novel aspect, in the power saving method, the UE 102 can receive a second DCI from the network node 101 before entering the power saving mode based on the first power saving duration, where the second DCI indicates a second power saving duration and a second additional monitoring duration.

[0040] Although the present application has been described in connection with certain specific embodiments for instructional purposes, the present application is not limited thereto. Accordingly, various modifications, changes, and combinations of the described embodiments in addition to those not specifically described will be apparent to those of ordinary skill in the art upon admittance to this description. Therefore, it is intended that the scope of the present application be indicated by the scope of the claims which follow.

Claims

1. A power saving method for monitoring a data channel, comprising: receiving, by a user equipment, a first downlink control information (DCI) from a network node, wherein the first DCI indicates a first power saving duration and a first additional monitoring duration; determining whether data scheduled by the first DCI is successfully decoded; and in case that it is determined that the data scheduled by the first DCI is not successfully decoded, performing monitoring for a period of time based on the first additional monitoring duration before a power saving mode based on the first power saving duration; if it is determined that the data scheduled by the first DCI is successfully decoded, performing the power saving mode based on the first power saving duration. 2.The method of claim 1, further comprising: determining whether the data scheduled by the first DCI is successfully decoded based on whether a HARQ ACK is transmitted by the user equipment.

3. The method of claim 1, wherein, the first additional monitoring duration is configured as a sum of a drx-HARQ-RTT-TimerDL duration and a drx-RetransmissionTimerDL duration for downlink transmission, or the first additional monitoring duration is configured as a sum of a drx-HARQ-RTT-TimerUL duration and a drx-RetransmissionTimerUL duration for uplink transmission. 4.The method of claim 1, further comprising: receiving, by the user equipment, a second DCI from the network node before entering the power saving mode based on the first power saving duration, wherein the second DCI indicates a second power saving duration and a second additional monitoring duration. 5.The method of claim 4, further comprising: determining a duration of the power saving mode based on an overlapping duration of the first power saving duration and the second power saving duration. 6.The method of claim 4, further comprising: determining a duration of the power saving mode based on the second power saving duration.

7. The method of claim 1, wherein, the user equipment remains in the power saving mode until receiving an indication to leave the power saving mode.

8. The method of claim 1, wherein, the user equipment leaves the power saving mode after the first power saving duration expires. 9.A power saving user equipment for monitoring a data channel, comprising: a receiver, configured to receive a first downlink control information (DCI) from a network node, wherein the first DCI indicates a first power saving duration and a first additional monitoring duration; and a processor, configured to determine whether data scheduled by the first DCI is successfully decoded; wherein, in case that it is determined that the data scheduled by the first DCI is not successfully decoded, the processor performs monitoring for a period of time based on the first additional monitoring duration before a power saving mode based on the first power saving duration, and if it is determined that the data scheduled by the first DCI is successfully decoded, the user equipment performs the power saving mode based on the first power saving duration.

10. The user equipment of claim 9, wherein, the user equipment determines whether the data scheduled by the first DCI is successfully decoded based on whether a HARQ ACK is transmitted.

11. The user equipment of claim 9, wherein, The first additional monitoring duration is configured as a sum of a drx-HARQ-RTT-TimerDL duration and a drx-RetransmissionTimerDL duration for downlink transmission, or a sum of a drx-HARQ-RTT-TimerUL duration and a drx-RetransmissionTimerUL duration for uplink transmission.

12. The user equipment of claim 9, wherein, The receiver receives a second DCI from the network node before the user equipment enters the power saving mode based on the first power saving duration, wherein the second DCI indicates a second power saving duration and a second additional monitoring duration.

13. The user equipment of claim 12, wherein, The processor determines a duration of the power saving mode based on an overlapping duration of the first power saving duration and the second power saving duration.

14. The user equipment of claim 12, wherein, The processor determines a duration of the power saving mode based on the second power saving duration.

15. The user equipment of claim 9, wherein, The user equipment remains in the power saving mode until receiving an indication to leave the power saving mode.

16. The user equipment of claim 9, wherein, The user equipment leaves the power saving mode after the first power saving duration expires.

17. A power saving user equipment for monitoring a data channel, comprising: a processor coupled to a transceiver and a memory, the memory having stored therein program instructions and data that, when executed by the processor, cause the user equipment to perform operations recited in any of claims 1-8.

18. A non-transitory computer readable storage medium having stored therein program instructions and data that, when executed by a processor of a power saving user equipment for monitoring a data channel, cause the user equipment to perform operations recited in any of claims 1-8.

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