Method and device for determining DRX RTT timer

Abstract

The present application relates to a method and apparatus for determining a DRX RTT timer. One embodiment of the present application provides a method for determining a discontinuous reception (DRX) round trip time (RTT) timer, comprising: determining an offset value based on at least one of the following parameters: a timing advance value, a common offset value, ephemeris information, and an offset value of a timing advance; and determining the DRX RTT timer using the offset value.

Description

Technical Field

[0001] The present application relates to wireless communication technology, and more particularly, to a method and apparatus for determining a discontinuous reception (DRX) round trip time (RTT) timer. Background Art

[0002] The legacy hybrid automatic repeat request (HARQ) RTT timer for DRX is designed to allow the user equipment (UE) to wait for feedback and scheduling time between the base station (BS) and the UE during the round trip time. The round trip delay caused by the distance between the BS and the UE in New Radio (NR) is on the order of a few microseconds, so this time is negligible and not accounted for in the HARQ RTT timer for DRX. However, there are networks with larger round trip delays (RTDs), ranging from a few milliseconds to hundreds of milliseconds, caused by the greater distance between the BS and the UE, which must be accounted for during DRX operation.

[0003] Therefore, it is desirable to provide a solution to incorporate the impact of larger RTD on the legacy HARQ RTT timer for DRX operation. Summary of the Invention

[0004] The present disclosure proposes adding an offset value to the HARQ RTT timer to reduce the waiting time of the UE.

[0005] One embodiment of the present application provides a method for determining a discontinuous reception (DRX) round trip time (RTT) timer, comprising: determining an offset value based on at least one of the following parameters: a timing advance value, a common offset value, ephemeris information, and an offset value of the timing advance; and determining the DRX RTT timer using the offset value.

[0006] Another embodiment of the present application provides a method for determining a discontinuous reception (DRX) round trip time (RTT) timer, comprising: receiving a DRX RTT timer, wherein the DRX RTT timer includes an indicator indicating that the DRX RTT timer is for a specific network with large delay variation; and applying the DRX RTT timer when a user equipment (UE) is served by the specific network.

[0007] Yet another embodiment of the present application provides a method for determining a discontinuous reception (DRX) round trip time (RTT) timer, the method comprising: receiving an adjustment configuration from a base station (BS); adjusting an offset value when a user equipment (UE) is allowed to adjust the offset value; and determining the DRX RTT timer based on the adjusted offset value.

[0008] Yet another embodiment of the present application provides an apparatus comprising: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receive circuit system; a transmit circuit system; and a processor coupled to the non-transitory computer-readable medium, the receive circuit system, and the transmit circuit system, wherein the computer-executable instructions cause the processor to implement a method for determining a discontinuous reception (DRX) round trip time (RTT) timer, the method comprising: determining an offset value based on at least one of the following parameters: a timing advance value, a common offset value, ephemeris information, and an offset value for a timing advance; and determining the DRX RTT timer using the offset value. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present disclosure.

[0010] Figure 2 A method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0011] Figure 3 Another method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0012] Figure 4 Another method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0013] Figure 5 A block diagram illustrating a UE according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

[0015] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, the embodiments are provided in the context of specific network architectures and new service cases (e.g., 3GPP 5G, 3GPP LTE Release 8, etc.). It is contemplated that as network architectures and new service cases evolve, all embodiments in the present application are also applicable to similar technical problems; and further, the terminology used in the present application may vary without affecting the principles of the present application.

[0016] Figure 1 A wireless communication system 100 is depicted in accordance with an embodiment of the present disclosure.

[0017] like Figure 1As shown in FIG, a wireless communication system 100 includes two UEs (UE 101-A, 101-B) and a base station 102. Figure 1 In the example, there are only two UEs and one base station (BS) in wireless communication system 100. However, those skilled in the art will recognize that any number of user equipment and base stations may be included in wireless communication system 100. Wireless communication system 100 may be a non-terrestrial network (NTN). Compared to UE 101-B, UE 101-A is located at a different position relative to BS 102. Therefore, the RTD of UE 101-A is greater than the RTD of UE 101-B. In other words, different UEs in the same network may have different RTDs.

[0018] UE 101-A may include a computing device such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), an in-vehicle computer, a network device (e.g., a router, a switch, and a modem), or the like. According to embodiments of the present disclosure, UE 101-A may include a portable wireless communication device, a smartphone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of sending and receiving communication signals over a wireless network. In some embodiments, UE 101-A includes a wearable device such as a smartwatch, a fitness band, an optical head-mounted display, or the like. UE 101-A may also be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or other terms used in the art. UE 101-A may communicate directly with BS 102 via uplink (UL) communication signals.

[0019] BS 102 may be distributed throughout a geographic area. In an NTN system, station 102 may be a satellite. In certain embodiments, BS 102 may also be referred to as an access point, access terminal, base station, base station, macro cell, Node-B, enhanced Node-B (eNB), home Node-B, relay node, device, or any other term used in the art. BS 102 may generally be part of a radio access network that may include one or more controllers communicatively coupled to one or more corresponding base stations.

[0020] The wireless communication system 100 is compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA)-based network, a code division multiple access (CDMA)-based network, an orthogonal frequency division multiple access (OFDMA)-based network, an LTE network, a 3rd Generation Partnership Project (3GPP)-based network, a 3GPP 5G network, a satellite communication network, a high altitude platform network, and / or other communication networks.

[0021] In one embodiment, the wireless communication system 100 complies with the NR of the 3GPP protocol, wherein the BS 102 transmits using an orthogonal frequency division multiple access (OFDM) modulation scheme on the DL, and the UE 101-A transmits using a single carrier frequency division multiple access (SC-FDMA) scheme or an OFDM scheme on the UL. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocol, such as WiMAX, as well as other protocols.

[0022] In other embodiments, BS 102 may communicate using other communication protocols, such as the IEEE 802.11 family of wireless communication protocols. Furthermore, in some embodiments, BS 102 may communicate via a licensed spectrum, while in other embodiments, BS 102 may communicate via an unlicensed spectrum. This application is not intended to be limited to any particular wireless communication system architecture or protocol implementation. In another embodiment, BS 102 may communicate with UE 101-A using 3GPP 5G protocols.

[0023] Currently, a work item on "NR Solutions for Non-Terrestrial Networks (NTNs)" has been approved. One objective related to the DRX solution in NTNs is to introduce an offset to the downlink DRX HARQ RTT (denoted as drx-HARQ-RTT-TimerDL) and the uplink DRX HARQ RTT (denoted as drx-HARQ-RTT-TimerUL) if HARQ feedback is enabled. If HARQ is disabled depending on the HARQ process, adaptation is performed within the HARQ process.

[0024] According to the legacy HARQ RTT timer for DRX, the UE needs to wait for the round-trip time between the base station (BS) and the UE. Round-trip delay is the time required to wait for feedback and scheduling between the base station (BS) and the UE. The round-trip delay (RTD) of a signal traveling from the UE to the BS, or vice versa, is typically very small, for example, on the order of a few microseconds. Therefore, this time is negligible and is not considered in the legacy HARQ RTT timer for DRX.

[0025] However, some wireless communication systems have large RTDs between the base station and the UE. For example, according to 3GPP documentation, the RTD in an NTN system can reach hundreds of milliseconds. Therefore, it is necessary to add an offset to the HARQ RTT timer to accommodate the large RTDs of some communication systems. Otherwise, the UE may need to monitor the Physical Downlink Control Channel (PDCCH) unnecessarily, which wastes UE power.

[0026] In the NTN system, the distance between the NTN node and the ground UE is relatively long, which will result in a large RTD between the NTN node and the ground UE. For example, the following Table 1 presents the RTD values of different NTN solutions:

[0027] Table 1

[0028]

[0029] According to Table 1, for NTN scenario A with a GEO transparent payload, the satellite altitude is 35,786 km, meaning the distance between the satellite base station and the UE is long. Accordingly, the maximum propagation delay contribution to the round-trip delay on the radio interface between the gNB and the UE is 541.46 ms. The minimum propagation delay contribution to the round-trip delay on the radio interface between the gNB and the UE is 477.48 ms. For NTN scenarios D1 and D2 with LEO regenerative payloads, the maximum propagation delay contribution to the round-trip delay on the radio interface between the gNB and the UE is 12.89 ms, and the minimum propagation delay contribution is 4 ms. Therefore, RTD in NTN networks is non-negligible.

[0030] Furthermore, the RTD value is different not only for different scenes but also for the same scene.

[0031] For example, propagation delay can vary as seen by the UE, particularly for LEO scenarios such as scenarios C and D. Delay variation measures how quickly the RTD changes over time as the satellite moves toward or away from the UE. Table 2 below presents the maximum delay variation for different scenarios:

[0032] Table 2

[0033]

[0034] In scenarios A and B, a geostationary satellite orbits 35,786 km above the Earth's equator in a circular orbit, tracking the Earth's rotation. An object in this orbit has an orbital period equal to the Earth's rotational period, and therefore appears stationary at a fixed location in the sky to an observer on Earth. Therefore, the latency variation seen by the UE is negligible.

[0035] However, for low-Earth orbit satellites, their altitude around the Earth is between 300km and 1500km. They are not static for ground UEs. For example, for scenario C1, the worst-case delay variation can be + / -40μs / sec. Considering that the maximum NTN beam coverage area is 1000km and the relative velocity of the satellite with respect to the Earth is 7.56km / sec, the RTD variation can be as high as 5ms. Considering the RTD range of scenario C1, this relatively large variation value is from 8ms to 25.77ms. Therefore, when utilizing the offset value drx-HARQ-RTT-TimerDL for the downlink DRX HARQ RTT and the offset value drx-HARQ-RTT-TimerUL for the uplink DRX HARQ RTT, this delay variation needs to be addressed.

[0036] In view of the above, the present disclosure proposes a solution in which the UE determines an offset value, so that the DRX HARQ RTT timer can be adjusted according to the offset value.

[0037] The offset of the DRX RTT timer may be determined based on the timing advance (TA) value between the downlink and uplink, which is denoted by N in this disclosure. TA Indicates. The UE shall maintain the TA value for uplink synchronization in Radio Resource Control (RRC)_CONNECTED mode. The initial TA value is received in a timing advance command (TAC) in a random access response (RAR) message or message B (MSGB). The initial TA value may also be received with an absolute TAC in response to a message A (MSGA) transmission containing a cell radio network temporary identifier (C-RNTI) medium access control (MAC) control element (CE). The BS may then adjust the TA value using the TAC MAC CE. Correspondingly, after receiving the TAC MAC CE with the TA adjustment, the UE shall then adjust the TA value according to the maintained TA value and the TA adjustment in the TAC MAC Ce.

[0038] There are several solutions for determining the offset value used to calculate the DRX HARQ RTT timer. In one solution, the offset value is equal to the TA value obtained from the physical layer, which is denoted as N TA , and therefore the offset value = N TA .

[0039] In another method, the BS may broadcast a common offset value in the system information. In this case, the offset value is equal to the maintained TA value plus the common offset value, ie, offset value = N TA +Common offset value. The common offset value can be positive or negative, depending on the specific conditions.

[0040] In another method, the BS may indicate the offset value of the timing advance value in the TAC MAC CE, which is expressed as N TA_offset In this case, the offset value is equal to the offset value plus the offset of the timing advance value, that is, the offset value = offset value + N TA_offset .

[0041] In another embodiment, the offset value may be determined based on ephemeris information. Ephemeris information may include satellite orbits and satellite motion information of satellites. Based on the ephemeris information, the UE may determine the position of the satellite and calculate the distance between the satellite and the UE. Therefore, the UE may determine the RTD between the satellite and the UE. In summary, the offset value may be calculated based on the ephemeris information, which is denoted as ephemeric_info. Thus, offset value = f(ephemeric_info). Calculation of the offset value may be implemented by the UE.

[0042] After determining the offset value, the UE uses the determined offset value to determine the DRX HARQ RTT timer. The determination of the offset value and the DRX HARQ RTT timer may occur at different time occasions.

[0043] For the first case, the determination is performed after receiving and applying the timing advance command MAC CE. The UE may determine the offset value after receiving and applying the timing advance command MAC CE and from the maintained N TA The UE calculates the DRX HARQ RTT timer based on the value. More specifically, the UE may receive the TAC MAC CE, apply the received timing advance command, and adjust the maintained TA value. The UE then obtains the adjusted TA value from the physical layer, determines it as the offset value for the DRX RTT timer, and updates the DRX RTT timer with the adjusted TA value.

[0044] The 3GPP specification may be modified as follows (modified parts are underlined):

[0045]

[0046] The sentence "determining or deriving the offset value of the DRX RTT timer based on the TA value" mentioned above and below is a general description, which may include all the options mentioned above. For example, it may include all ways of determining the offset value.

[0047] For the second case, the determination is performed after receiving and applying the Timing Advance Command MAC CE in the RAR message or MSGB. More specifically, the UE may receive the TAC MAC CE in the RAR message or MSGB, and then the UE applies the TAC as the TA value N. TA After that, the UE obtains the offset value N from the physical layer. TAAnd calculate the DRX HARQ RTT timer.

[0048] The 3GPP specification may be modified as follows (modified parts are underlined):

[0049]

[0050] For the third scenario, the determination is performed after receiving and applying the absolute TAC in response to the MSGA transmission containing the C-RNTI MAC CE. That is, the UE may receive the absolute TAC MAC CE and apply the received absolute TAC as the TA value N TA After that, the UE obtains the TA value N from the physical layer. TA , determine the TA value from the physical layer as the offset value of the DRX RTT timer, and update the DRX RTT timer.

[0051] The 3GPP specification may be modified as follows (modified parts are underlined):

[0052]

[0053] For the fourth scenario, the determination is performed after configuring or reconfiguring DRX. After the UE receives the DRX configuration from the higher layer, the UE obtains the TA value N from the physical layer. TA , determine it as the offset value of the DRX RTT timer, and update the DRX RTT timer.

[0054] The 3GPP specification may be modified as follows (modified parts are underlined):

[0055]

[0056] For the fifth occasion, the determination is performed before starting a timer for uplink or downlink transmission of DRX RTT HARQ.

[0057] For one example, after receiving the MAC protocol data unit (PDU) in the configured downlink allocation and before starting the timer drx-HARQ-RTT-TimerDL, the UE obtains the TA value N from the physical layer. TA , determine it as the offset value of the DRX RTT timer, and update the DRX RTT timer. The DRX RTT timer is calculated as follows: drx-HARQ-RTT-TimerDL = drx-HARQ-RTT-TimerDL + [offset_value].

[0058] For another example, after transmitting the MAC PDU in the configured uplink grant and before starting the timer drx-HARQ-RTT-TimerUL, the UE obtains the TA value N from the physical layer. TA , determine it as the offset value of the DRX RTT timer, and update the DRX RTT timer. The DRX RTT timer is calculated as follows: drx-HARQ-RTT-TimerUL = drx-HARQ-RTT-TimerUL + [offset_value].

[0059] The 3GPP specification may be modified as follows (modified parts are underlined):

[0060]

[0061] For the third example, after receiving the PDCCH indicating DL transmission and before starting the timer drx-HARQ-RTT-TimerDL, the UE obtains the TA value N from the physical layer. TA , determine it as the offset value of the DRX RTT timer, and update the DRX RTT timer. The DRX RTT timer is calculated as follows: drx-HARQ-RTT-TimerDL = drx-HARQ-RTT-TimerDL + [offset_value].

[0062] The 3GPP specification may be modified as follows (modified parts are underlined):

[0063]

[0064] For the fourth example, after receiving the PDCCH indicating UL transmission and before starting the timer drx-HARQ-RTT-TimerUL, the UE obtains the TA value N from the physical layer TA , determine it as the offset value of the DRX RTT timer, and update the DRX RTT timer. The DRX RTT timer is calculated as follows: drx-HARQ-RTT-TimerUL = drx-HARQ-RTT-TimerUL + [offset_value].

[0065] The 3GPP specification may be modified as follows (modified parts are underlined):

[0066]

[0067] In the above description, the UE determines the DRX HARQ RTT timer. Alternatively, the network may directly configure the DRX HARQ RTT timer for the UE and transmit the timer in an RRC reconfiguration message, which may be denoted as DRX-Config. After receiving the configuration, the UE directly applies the received timer when served by a network with a larger RTD. For example, the network may be an NTN network with a larger RTD, and when the UE is served by an NTN node, it uses the DRX HARQ RTT timer received from the network.

[0068] The present disclosure introduces two new timers for the DRX HARQ RTT timer for networks with large RTDs. When the network with large RTD is an NTN system, the downlink DRX HARQ RTT timer of the NTN system can be expressed as drx-HARQ-RTT-TimerDL-NTN, and the uplink DRX HARQ RTT timer can be expressed as drx-HARQ-RTT-TimerUL-NTN. Then, the 3GPP document regarding the two timers in the RRC reconfiguration message can be modified as follows (modified parts are underlined):

[0069]

[0070] When DRX is configured for a UE, the UE may directly apply the timer drx-HARQ-RTT-TimerDL-NTN configured by the BS, and the 3GPP specification may be modified as follows (modified parts are underlined):

[0071]

[0072] Due to the introduction of two new timers for NTN networks, when the downlink or uplink DRX HARQ RTT timer has been started, the UE needs to determine whether it is served by a non-NTN node or an NTN node. The 3GPP specification can be modified as follows (the modified parts are underlined):

[0073]

[0074] When the PDCCH indicates a downlink or uplink transmission, the UE needs to decide whether to configure the newly introduced timer drx-HARQ-RTT-TimerDL-NTN or drx-HARQ-RTT-TimerUL-NTN. When both timers are configured, it indicates that the UE is served by an NTN node, so the timer drx-HARQ-RTT-TimerDL-NTN or timer drx-HARQ-RTT-TimerUL-NTN should be used instead of the timer configured for a non-NTN node. The 3GPP specification can be modified as follows (modified parts are underlined):

[0075]

[0076] The BS may also transmit an adjustment configuration to the UE. The adjustment configuration may include at least one of the following parameters: an indicator for enabling the UE to perform adjustment of the DRX RTT timer, an indicator for adjusting the period, a timer for adjustment, and a specific offset value. The adjustment configuration may be transmitted to the UE in a PDCCH or MAC CE.

[0077] The indicator for implementing UE-based adjustment is transmitted to the UE via RRC signaling with a size of 1 bit. If the bit value = 1, the UE will adjust the offset value based on the network configuration; otherwise, the UE will not adjust the offset value. Alternatively, if the bit value = 0, the UE will adjust the offset value based on the network configuration; otherwise, the UE will not adjust the offset value.

[0078] When the UE is allowed to adjust the offset value, the network may further configure how often the UE will adjust the offset value. This may be achieved through periodic adjustment or an adjustment timer. For example, the network may configure a periodic value for the UE, and the UE will periodically adjust the offset value based on the periodic value configured by the network. In another example, the network may configure a timer for the UE, and the UE will start the timer when the UE determines the offset value, when the UE starts the DRX RTT timer, or when the UE last adjusts the offset value. When the timer expires, the UE adjusts the offset value.

[0079] In addition, the network may configure an adjustment step size for the UE, and each time the UE adjusts the offset value, the UE adjusts the offset value by adding an adjustment step size from the network.

[0080] In another embodiment, the UE may adjust the offset value by network indication. The network may indicate the offset adjustment via PDCCH or MAC CE, and the UE may then adjust the offset value according to the received offset adjustment command. For example, the UE has an initial offset value x from, for example, system information. Then, after a period of time, the network indicates an adjustment value y in PDCCH or MAC CE, where y may be positive or negative, and the UE may adjust the offset value by adding x to y, for example, x=x+y. The UE may then apply the updated x to the DRX RTT timer as follows:

[0081] i.drx-HARQ-RTT-TimerDL=drx-HARQ-RTT-TimerDL+x; and

[0082] ii.drx-HARQ-RTT-TimerUL=drx-HARQ-RTT-TimerUL+x.

[0083] Figure 2 A method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0084] In step 201, the UE determines an offset value based on at least one of the following parameters:

[0085] i. Timing advance value, i.e. N TA , which is obtained from the physical layer;

[0086] ii. A common offset value, which is indicated in the system information broadcast by the BS;

[0087] iii. ephemeris information; and

[0088] iv. The timing advance offset value, which is indicated in the TAC MAC CE.

[0089] In step 202, the UE determines the DRX RTT timer using the offset value.

[0090] The UE has different timing occasions to determine the offset. For example, the UE may:

[0091] i. The offset value is determined after receiving and applying the TAC MAC CE, which may be received in a random access response message or in message B (MSGB);

[0092] ii. After receiving the absolute TAC in response to the MSGA transmission and after applying the absolute TAC, determining the offset value;

[0093] iii. Determine the offset value after configuring or reconfiguring DRX; and

[0094] iv. Determine the offset value before starting the timer for uplink or downlink transmission of DRX RTT HARQ.

[0095] Figure 3 Another method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0096] In step 301, a UE receives a DRX RTT timer, where the DRX RTT timer includes an indicator indicating that the DRX RTT timer is for a specific network with large delay variation. In step 302, the UE applies the DRX RTT timer when the UE is served by the specific network. For example, the specific network may be an NTN, which has a large RTD, and some NTNs have large delay variation.

[0097] Figure 4 Another method for wireless communication performed by a UE according to a preferred embodiment of the present disclosure is described.

[0098] In step 401, the UE receives an adjustment configuration from the BS; in step 402, when the UE is allowed to adjust the offset value, the UE adjusts the offset value; and in step 403, the UE determines a DRX RTT timer based on the adjusted offset value.

[0099] The adjustment configuration may include an indicator for allowing the UE to adjust the offset value. If the UE is allowed to adjust the offset value, the UE may adjust the offset value periodically using the period indicated in the configuration, or when a timer in the adjustment configuration expires. The BS may further transmit the adjustment value in the adjustment configuration to the UE, and the UE may use the adjustment value to adjust the offset value. The BS may also broadcast a common offset value indicated in system information, and upon receiving the common offset value, the UE may use the common offset value to adjust the offset value.

[0100] Figure 5 A block diagram illustrating a UE according to some embodiments of the present disclosure. UE 101-A may include receive circuitry, a processor, and transmit circuitry. In one embodiment, UE 101-A may include: a non-transitory computer-readable medium having computer-executable instructions stored thereon; receive circuitry; transmit circuitry; and a processor coupled to the non-transitory computer-readable medium, the receive circuitry, and the transmit circuitry. The computer-executable instructions may be programmed to implement a method (e.g., Figure 2 That is, when executing the computer-executable instructions, the processor may determine an offset value based on at least one of the following parameters: a timing advance value, a common offset value, ephemeris information, and an offset value of the timing advance, and use the offset value to determine the DRX RTT timer.

[0101] The methods of the present disclosure can be implemented on a programmed processor. However, the controller, flow charts, and modules can also be implemented on a general-purpose or special-purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit components, an integrated circuit, hardware electronic or logic circuits (e.g., discrete element circuits), a programmable logic device, or the like. In general, any device having a finite state machine capable of implementing the flow charts shown in the figures can be used to implement the processing functions of the present disclosure.

[0102] Although the present disclosure has been described with reference to specific embodiments thereof, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, the various components of an embodiment may be interchanged, added, or replaced in other embodiments. Moreover, not all of the elements shown in each figure are necessary for the operation of the disclosed embodiments. For example, a person skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0103] In the present disclosure, relative terms such as "first", "second" and the like can be used alone to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual relationship or order between such entities or actions. The term "comprise / comprising" or any other variation thereof is intended to encompass non-exclusive inclusion, such that the process, method, article or device comprising a list of elements not only comprises those elements but also may comprise other elements that are not explicitly listed or inherent to this process, method, article or device. An element beginning with "a, an" or the like (without further constraints) does not exclude the presence of additional identical elements in the process, method, article or device comprising the element. Moreover, the term "another" is defined as at least one second or more. As used herein, the terms "comprise", "have" and the like are defined as "comprising".

Claims

1. An apparatus for determining a discontinuous reception (DRX) round trip time (RTT) timer, comprising: a non-transitory computer-readable medium having computer-executable instructions stored thereon; receiving circuit system; transmission circuit systems; and a processor coupled to the non-transitory computer-readable medium, the receive circuitry, and the transmit circuitry, wherein the computer-executable instructions cause the processor to implement a method for determining the DRX RTT timer, the method comprising: determining an offset value based on the timing advance value and at least one of the following parameters: a common offset value, ephemeris information, and an offset value of the timing advance; and The DRX RTT timer is determined using the offset value. The apparatus according to claim 1 , wherein the timing advance value is obtained from a physical layer. 3 . The apparatus of claim 1 , wherein the common offset value is indicated in system information broadcast by a base station (BS).

4. The apparatus of claim 1, wherein the offset value of the timing advance is indicated in a timing advance command (TAC) medium access control (MAC) control element (CE).

5. The apparatus of claim 1 , wherein determining the offset value further comprises: The offset value is determined after receiving and applying a timing advance command (TAC) medium access control (MAC) control element (CE). 6 . The apparatus of claim 5 , wherein the TAC MAC CE is received in a random access response message or in a message B (MSGB).

7. The apparatus of claim 1 , wherein determining the offset value further comprises: The offset value is determined after receiving an absolute timing advance command (TAC) in response to a message A (MSGA) transmission and after applying the absolute TAC.

8. The apparatus of claim 1 , wherein determining the offset value further comprises: The offset value is determined after configuring or reconfiguring DRX.

9. The apparatus of claim 1 , wherein determining the offset value further comprises: The offset value is determined before starting a timer for uplink or downlink transmission of DRX RTT HARQ.

10. An apparatus for determining a discontinuous reception (DRX) round trip time (RTT) timer, comprising: a non-transitory computer-readable medium having computer-executable instructions stored thereon; receiving circuit system; transmission circuit systems; and a processor coupled to the non-transitory computer-readable medium, the receive circuitry, and the transmit circuitry, wherein the computer-executable instructions cause the processor to implement a method for determining the DRX RTT timer, the method comprising: receiving an adjustment configuration from a base station (BS); When a user equipment (UE) is allowed to adjust an offset value, adjusting the offset value, wherein the offset value is determined based on a timing advance value and at least one of the following parameters: a common offset value, ephemeris information, and an offset value of the timing advance; and The DRX RTT timer is determined based on the adjusted offset value.

11. The apparatus of claim 10, further comprising: The UE is allowed to adjust the offset value based on the adjustment configuration.

12. The apparatus of claim 10, wherein adjusting the offset value further comprises: The offset value is periodically adjusted with a period indicated in the adjustment configuration.

13. The apparatus of claim 10, wherein adjusting the offset value further comprises: The offset value is adjusted when a timer in the adjustment configuration expires.

14. The apparatus of claim 10, wherein adjusting the offset value further comprises: The offset value is adjusted using an adjustment value indicated in the adjustment configuration received from the BS.

15. The apparatus of claim 10, wherein adjusting the offset value further comprises: After receiving the offset adjustment command, the offset value is adjusted using the common offset value indicated in the system information broadcast by the BS.

16. A method for determining a discontinuous reception (DRX) round trip time (RTT) timer, the method comprising: determining an offset value based on the timing advance value and at least one of the following parameters: a common offset value, ephemeris information, and an offset value of the timing advance; and The DRX RTT timer is determined using the offset value. The method of claim 16 , wherein the timing advance value is obtained from a physical layer.

18. The method of claim 16, wherein the common offset value is indicated in system information broadcast by a base station (BS).

19. The method of claim 16, wherein the offset value of the timing advance is indicated in a timing advance command (TAC) medium access control (MAC) control element (CE).

20. The method of claim 16, wherein determining the offset value further comprises: The offset value is determined after receiving and applying a timing advance command (TAC) medium access control (MAC) control element (CE).

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