EP3688909A1

EP3688909A1 - Service data unit management

Info

Publication number: EP3688909A1
Application number: EP18782095.6A
Authority: EP
Inventors: Henri Koskinen
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2017-09-28
Filing date: 2018-09-24
Publication date: 2020-08-05
Also published as: WO2019063880A1

Abstract

Certain embodiments may relate to communication systems, and, for example, some embodiments may relate to timer-based discarding of a packet data convergence protocol (PDCP) service data unit (SDU). According to a first embodiment, a method may include transmitting, by a first higher-level protocol entity, a service data unit within a packet data unit to a first lower-level protocol entity. The method may also include transmitting, by the first higher-level protocol entity to the first lower-level protocol entity, an indication for discarding the packet data unit. In addition, the method may include receiving, by the first higher-level protocol entity, a response to the indication from the first lower-level protocol entity. Further, based on the response or lack of response, the method may include transmitting, by the first higher-level protocol entity to a second higher-level protocol entity, an instruction not to wait for reception of the SDU.

Description

TITLE:

SERVICE DATA UNIT MANAGEMENT

CROSS REFERENCE TO RELATED APPLICATION:

[0001] This application claims the benefit of U.S. Provisional Application No. 62/564,752, filed September 28, 2017. The entire content of the above-referenced application is hereby incorporated by reference.

BACKGROUND:

Field:

[0002] Certain embodiments may relate to communication systems involving transmission of protocol data units (PDUs) and service data units (SDUs). In particular, managing an SDU associated with a given sequence number may be used in a communication system to provide improved utilization of network resources.

Description of the Related Art:

[0003] In a communication system, such as a Long-Term Evolution (LTE) network, 5th generation (5G) mobile network, or any other next-generation network system, one or more entities may include one or more layered protocol entities, such as one or more packet data convergence protocol (PDCP) entities, one or more radio link control (RLC) entities, one or more medium access control (MAC) entities, and one or more physical (PHY) entities. In some embodiments, a PDCP entity may be associated with a PDCP protocol layer, a RLC entity may be associated with a RLC protocol layer, a MAC entity may be associated with a MAC protocol layer, and a PHY entity may be associated with a PHY protocol layer. In certain embodiments, one or more protocol entities may be arranged according to one or more layers. For example, one or more PDCP entities may be higher-level protocol entities, and one or more RLC entities may be lower-level protocol entities, with the one or more PDCP entities being at a higher level than the one or more RLC entities. In some embodiments, one or more MAC entities and/or one or more PHY entities may be lower-level protocol entities, with the one or more MAC entities and/or one or more PHY entities being at a lower level than one or more LC entities.

[0004] Communication between entities often fails to inform a PDCP entity regarding a discarded PDCP PDU. A first PDCP entity may send an indication not to wait for reception of an SDU to a second PDCP entity, despite the PDCP PDU already being transmitted at a first lower-level protocol entity. In such a case, the corresponding SDU may not be delivered to a higher layer despite being received, resulting in packet loss and wasted network resources.

SUMMARY:

[0005] In accordance with some embodiments, a method may include transmitting, by a first higher- level protocol entity, a service data unit within a packet data unit to a first lower-level protocol entity. The method may further include transmitting, by the first higher-level protocol entity to the first lower-level protocol entity, an indication for discarding the packet data unit. The method may further include receiving, by the first higher-level protocol entity, a response to the indication from the first lower-level protocol entity. The method may further include, based on the response or lack of response, transmitting, by the first higher-level protocol entity to a second higher- level protocol entity, an instruction not to wait for reception of the service data unit.

[0006] In accordance with some embodiments, an apparatus may include means for transmitting a service data unit within a packet data unit to a first lower-level protocol entity. The apparatus may further include means for transmitting an indication for discarding the packet data unit. The apparatus may further include means for receiving a response to the indication from the first lower-level protocol entity. The apparatus may further include, based on the response or lack of response, means for transmitting an instruction not to wait for reception of the service data unit.

[0007] In accordance with some embodiments, an apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to at least transmit a service data unit within a packet data unit to a first lower-level protocol entity. The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to at least transmit an indication for discarding the packet data unit. The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to at least receive a response to the indication from the first lower-level protocol entity. The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to at least, based on the response or lack of response, transmit an instruction not to wait for reception of the service data unit.

[0008] In accordance with some embodiments, a non-transitory computer readable medium can be encoded with instructions that may, when executed in hardware, perform a method. The method may transmit a service data unit within a packet data unit to a first lower- level protocol entity. The method may further transmit an indication for discarding the packet data unit. The method may further receive a response to the indication from the first lower-level protocol entity. The method may further, based on the response or lack of response, transmit an instruction not to wait for reception of the service data unit.

[0009] In accordance with some embodiments, a computer program product may perform a method. The method may transmit a service data unit within a packet data unit to a first lower-level protocol entity. The method may further transmit an indication for discarding the packet data unit. The method may further receive a response to the indication from the first lower-level protocol entity. The method may further based on the response or lack of response, transmit an instruction not to wait for reception of the service data unit.

[0010] In accordance with some embodiments, an apparatus may include circuitry configured to transmit a service data unit within a packet data unit to a first lower-level protocol entity. The circuitry may further transmit an indication for discarding the packet data unit. The circuitry may further receive a response to the indication from the first lower- level protocol entity. The circuitry may further, based on the response or lack of response, transmit an instruction not to wait for reception of the service data unit. [0011] In accordance with some embodiments, a method may include receiving, by a first lower-level protocol entity, a service data unit from a first higher-level protocol entity. The method may further include receiving, by the first lower-level protocol entity from the first higher-level protocol entity, an indication for discarding the service data unit. The method may further include, in response to receiving the indication for discarding the service data unit, transmitting, by the first lower-level protocol entity, a response to the first higher-level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0012] In accordance with some embodiments, an apparatus may include means for receiving a service data unit from a first higher-level protocol entity. The apparatus may further include means for receiving an indication for discarding the service data unit. The apparatus may further include means for, in response to receiving the indication for discarding the service data unit, transmitting a response to the first higher-level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0013] In accordance with some embodiments, an apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus to at least receive a service data unit from a first higher- level protocol entity. The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to at least receive an indication for discarding the service data unit. The at least one memory and the computer program code can be further configured to, with the at least one processor, cause the apparatus to at least, in response to receiving the indication for discarding the service data unit, transmit a response to the first higher-level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0014] In accordance with some embodiments, a non-transitory computer readable medium can be encoded with instructions that may, when executed in hardware, perform a method. The method may receive a service data unit from a first higher-level protocol entity. The method may further receive an indication for discarding the service data unit. The method may further, in response to receiving the indication for discarding the service data unit, transmit a response to the first higher- level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0015] In accordance with some embodiments, a computer program product may perform a method. The method may receive a service data unit from a first higher-level protocol entity. The method may further receive an indication for discarding the service data unit. The method may further, in response to receiving the indication for discarding the service data unit, transmit a response to the first higher- level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0016] In accordance with some embodiments, an apparatus may include circuitry configured to receive a service data unit from a first higher-level protocol entity. The circuitry may further receive an indication for discarding the service data unit. The circuitry may further, in response to receiving the indication for discarding the service data unit, transmit a response to the first higher-level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0017] For a proper understanding of this disclosure, reference should be made to the accompanying drawings, wherein:

[0018] Figure 1 illustrates a system according to certain embodiments.

[0019] Figure 2 illustrates an example of a signaling diagram according to certain embodiments.

[0020] Figure 3 illustrates another example of a signaling diagram according to certain embodiments.

[0021] Figure 4 illustrates an example of a method according to certain embodiments. [0022] Figure 5 illustrates an example of another method according to certain embodiments.

DETAILED DESCRIPTION:

[0023] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearance of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

[0024] Certain embodiments contained herein may provide significant technical advantages. For example, certain embodiments may improve the process related to transmission of indications not to wait for reception of PDCP SDUs. By doing so, certain embodiments may reduce the overall resources utilized by entities by avoiding unnecessary use of network resources. Such a reduction in the overall resources may allow the network to dedicate the saved resources to other areas, thus improving overall network performance and utilization.

[0025] Figure 1 illustrates a system according to certain embodiments. According to some embodiments, a system may include multiple apparatuses, such as first apparatus 110 and/or second apparatus 120. In some embodiments, first apparatus 210 and/or second apparatus 220 may be one or more of user equipment, a mobile device, such as a mobile phone, smart phone, personal digital assistant (PDA), tablet, or portable media player, digital camera, pocket video camera, video game console, navigation unit, such as a global positioning system (GPS) device, desktop or laptop computer, single- location device, such as a sensor or smart meter, or any combination thereof. [0026] According to some embodiments, first apparatus 210 and/or second apparatus 220 may also be one or more of a base station, such as an evolved node B (eNB) or next generation node B (gNB), a next generation radio access network (NG RAN), a mobility management entity (MME), a serving gateway, a server, and/or any other access node or combination thereof.

[0027] One or more of apparatuses 110 and 120 may include at least one processor, respectively indicated as 11 1 and 121. At least one memory may be provided in one or more of apparatuses 110 and 120, indicated at 112 and 122, respectively. Memory 1 12, 122 may be fixed and/or removable. Memory 112, 122 may include computer program instructions or computer code contained therein. Processors 11 1, 121 and memories 112, 122, or a subset thereof, may be configured to provide means corresponding to the various blocks of Figures 2-5. Although not shown, one or more of apparatuses 1 10 and 120 may also include positioning hardware, such as global positioning system (GPS) or micro electrical mechanical system (MEMS) hardware, which may be used to determine a location of the corresponding apparatus. Other sensors are also permitted and may be included to determine location, elevation, orientation, and so forth, such as barometers, altimeters, compasses, and the like.

[0028] As shown in Figure 1, transceivers 113 and 123 may be provided, and one or more transceivers may include at least one antenna, respectively illustrated as 1 14 and 124. Apparatuses 110 and/or 120 may have many antennas, such as an array of antennas configured for multiple input multiple output (MIMO) communications, or multiple antennas for multiple radio access technologies. Other configurations of these apparatuses, for example, may be provided.

[0029] Transceivers 113 and 123 may be a transmitter, a receiver, both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception.

[0030] Processors 11 1 and 121 may be embodied by any computational or data processing device, such as a central processing unit (CPU), application specific integrated circuit (ASIC), or comparable device. The processors may be implemented as a single controller, or a plurality of controllers or processors. In addition, the processors may be general purpose or special purpose processors.

[0031] Memory 1 12 and 122 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate from the one or more processors. Furthermore, the computer program instructions stored in the memory and which may be processed by the processors may be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language.

[0032] The memory and the computer program instructions may be configured, with the processor for the particular apparatus, to cause an apparatus, such as user equipment, an eNB, or a gNB, to perform any of the processes described below (see, for example, Figures 2-5). Therefore, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions that, when executed in hardware, perform a process such as one of the processes described herein. Alternatively, certain embodiments may be performed entirely in hardware.

[0033] Figure 2 illustrates an example of one or more protocol entities in a cellular network, such as a LTE network, 5G, and/or New Radio network, transmitting and/or receiving one or more PDUs and/or SDUs. In some embodiments, a cellular network may include one or more protocol entities, such as PDCP entities 212 and 222, RLC entities 214 and 224, MAC entities 216 and 226, and physical-layer entities 218 and 228. In accordance with some embodiments, one or more of the protocol entities may be included in one or more apparatuses, with one or more of the protocol entities included in one or more of the same or different apparatuses. For example, PDCP entity 212 may be included in the same apparatus as RLC entity 214, MAC entity 216, and/or PHY entity 218, such as first apparatus 110, while PDCP entity 222 may be included in the same apparatus as RLC entity 224, MAC entity 226, and PHY entity 228, such as second apparatus 120. In another example, PDCP entity 212, RLC entity 214, MAC entity 216, and/or PHY entity 218 may be included in different apparatuses.

[0034] In some embodiments, one or more Internet Protocol (IP) entities, such as IP entities 230 and 232, may be in communication with PDCP entities 212 and 232, respectively. One or more IP entities 230 and 232 may transmit one or more IP packets to one or more PDCP entities 212 and 222, which are received by one or more PDCP entities 212 and 222 as PDCP SDUs. One or more PDCP entities 212 and 222 may perform at least one of the following functions: header compression of the PDCP SDU, integrity protection, ciphering based upon a PDCP COUNT value, setting a PDCP sequence number of a PDCP PDU based upon a PDCP COUNT value, and/or incrementing the PDCP COUNT value by one for the next PDCP SDU. One or more PDCP entities 212 and 222 may also send a transmission to one or more lower- level protocol entities, for example, RLC entities 214 and 224, respectively. The transmission sent to the one or more lower-level protocol entities may be one or more PDCP PDUs/RLC SDUs.

[0035] Upon receiving one or more PDCP PDUs/RLC SDUs, a lower-level protocol entity, such as RLC entities 214 and 224, may perform one or more of segmentation of the RLC SDUs and/or adding headers based upon the mode of operation of the RLC. In some embodiments, RLC entities 214 and 224 may operate in one or more of an acknowledged mode and an unacknowledged mode. One or more RLC entities 214 and 224 may transmit one or more RLC PDUs/MAC SDUs to one or more lower-level protocol entities, for example, MAC entities 216 and 226.

[0036] Upon receiving one or more MAC SDUs, a lower-level protocol entity, such as one or more MAC entities 216 and 226, may perform one or more of padding and adding headers to form one or more MAC PDUs. One or more MAC entities 216 and 226 may transmit one or more MAC PDUs to one or more lower-level protocol entities, such as one or more physical-layer entities 218 and 228.

[0037] Figure 3 illustrates another example of a signal flow diagram according to certain embodiments. In step 301 , IP entity 330 may transmit an IP packet to PDCP entity 312, which is received at PDCP entity 312 as a PDCP SDU.

[0038] In step 303, higher-level PDCP entity 312 may transmit the PDCP SDU, associated with a sequence number, within a PDCP PDU to lower- level RLC entity 314. In step 305, PDCP entity 312 may transmit an indication for discarding the PDCP PDU to RLC entity 314. In response to receiving the indication for discarding the PDCP PDU in step 305, RLC entity 314 may transmit a response to PDCP entity 312, in step 307. In some embodiments, the response may confirm the discarding of the PDCP PDU indicated in step 305. In step 309, PDCP entity 312 may transmit an instruction to PDCP entity 322 not to wait for reception of the SDU associated with the sequence number.

[0039] Figure 4 illustrates an example method of a first higher-level protocol entity receiving a response from a lower- level protocol entity, and instructing a second higher- level protocol entity not to wait for reception of a service data unit.

[0040] In some embodiments, the first higher-level protocol entity may correspond to PDCP entity 212 and/or 312, the first lower-level protocol entity may correspond to RLC entity 214 and/or 314, and/or the second higher-level protocol entity may correspond to PDCP entity 222 and/or 322.

[0041] The first higher-level protocol entity, the first lower-level protocol entity, and/or the second lower- level protocol entity may be in the same or different apparatuses, such as first apparatus 110 and/or second apparatus 120. For example, the first higher-level protocol entity and first lower-level protocol entity may be in a first apparatus, and/or the second higher-level protocol entity may be in a second apparatus. In another example, the first higher-level protocol entity, the first lower-level protocol entity, and the second higher-level protocol entity may be in different apparatuses. In some embodiments, the first apparatus and/or the second apparatus may be user equipment, a base station, and/or an eNB.

[0042] In step 401, the first higher-level protocol entity may receive an SDU. In certain embodiments, the SDU may be received from an IP entity, such as IP entity 230 and/or 330.

[0043] In step 403, the first higher- level protocol entity may begin a timer. In some embodiments, the timer may be a discard timer and/or may be associated with the received SDU. In some embodiments, the first higher-level protocol entity may associate a count value with the SDU. The first higher- level protocol entity may perform at least one of the following: header compression of the SDU, integrity protection, ciphering based on the count value, setting a PDCP sequence number (SN) of a PDU carrying the SDU based on the count value, and/or incrementing the count value by one for a possible next SDU.

[0044] In step 405, the higher-level protocol entity may transmit the PDU to the first lower-level protocol entity.

[0045] In step 407, the first higher-level protocol entity may transmit an indication for discarding the PDU to the first lower-level protocol entity. In some embodiments, the first higher-level protocol entity may serve a duplication bearer. For example, the first higher-level protocol entity may send PDUs to two or more lower-level protocol entities, one of which may include the first lower-level protocol entity. In some embodiments, one or more of the two or more lower-level protocol entities may be included in the same and/or one or more different apparatuses as the first higher-level protocol entity. In embodiments where the first higher-level protocol entity serves a duplication bearer, one or more discard indications may be transmitted to one, at least one, or each lower-level protocol entity to which the first higher-level protocol entity has transmitted at least one PDU.

[0046] In step 409, in response to transmitting the indication for discarding the PDU in step 407, the first higher-level protocol entity may receive a response from the first lower-level protocol entity. In some embodiments, the response may confirm the discarding of the PDU.

[0047] In step 411 , the first higher-level protocol entity determines whether to send to the second higher-level protocol entity an instruction not to wait for reception of the SDU associated with the count value. The SDU may be associated with a sequence number.

[0048] In some embodiments, the determination in step 411 may be based upon at least one of the following: the type of the first lower-level protocol entity, such as the mode of RLC, and/or the status of the PDU. In certain embodiments, where the first higher- level protocol entity serves a duplication bearer, the determination may be based upon one or more responses received from the one or more lower-level protocol entities, including the first lower-level protocol entity.

[0049] The first higher-level protocol entity may determine, in some embodiments, not to send an instruction not to wait for reception of the SDU to the second higher-level protocol entity. For example, the first higher- level protocol entity may determine not to send an instruction not to wait for reception of the SDU to a second higher-level protocol entity based upon the delivery being unpreventable. Other reasons for determining not to send an instruction may include failing to receive a response from the first lower- level protocol entity, and/or that the discard timer is longer than a reordering timer operated by the second higher-level protocol entity. In certain embodiments, the first higher-level protocol entity may determine to send an instruction not to wait for reception of the SDU to the second higher-level protocol entity based upon an inability of the PDU to be received by the first higher-level protocol entity. For example, the PDU may be unable to be received due to a lower-level protocol, such as an LC protocol, operating in an Unacknowledged Mode, and refraining from submitting a final segment of the PDU to a MAC protocol level for transmission.

[0050] In step 413, upon determining to send to the higher-level protocol entity an instruction not to wait for reception of an SDU, the first higher-level protocol entity may transmit to the second higher-level protocol entity an instruction not to wait for reception of the SDU associated with a sequence number.

[0051] Figure 5 illustrates another example method of a first lower- level protocol entity transmitting a response to an indication from a first higher-level protocol entity for sending an instruction not to wait for reception of the SDU to a second higher-level protocol entity.

[0052] In some embodiments, the first lower-level protocol entity may correspond to RLC entity 214 and/or 314, the first higher-level protocol entity may correspond to PDCP entity 212 and/or 312, and/or the second higher- level protocol entity may correspond to PDCP entity 222 and/or 322.

[0053] The first lower- level protocol entity, the first higher-level protocol entity, and/or the second higher-level protocol entity maybe in the same or different apparatuses, such as first apparatus 110 and/or second apparatus 120. For example, the first higher-level protocol entity and first lower-level protocol entity may be in a first apparatus, and/or the second higher-level protocol entity may be in a second apparatus. In another example, the first higher-level protocol entity, the first lower-level protocol entity, and the second higher-level protocol entity may be in different apparatuses. In some embodiments, the first apparatus and/or the second apparatus may be user equipment, a base station, and/or an eNB.

[0054] In step 501, the first lower- level protocol entity may receive an SDU from the first higher-level protocol entity. In step 503, the first lower-level protocol entity may receive an indication for discarding the RLC SDU from the first higher-level protocol entity.

[0055] In response to receiving the indication for discarding the RLC SDU from the first higher-level protocol entity, the first lower-level protocol entity may transmit a response to the first higher-level protocol entity, as shown in step 505. In some embodiments, the response may be used to determine whether or not the first higher-level protocol entity should send an instruction not to wait for reception of the SDU to a second higher-level protocol entity based upon the delivery being unpreventable.

[0056] One having ordinary skill in the art will readily understand that certain embodiments discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations, which are different from those which are disclosed. Therefore, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.

[0057] Partial Glossary

[0058] 3GPP 3rd Generation Partnership Project

[0059] 5G 5th Generation

[0060] AM Acknowledged Mode

[0061] BS Base Station

[0062] IP Internet Protocol

[0063] LTE Long-Term Evolution

[0064] MAC Medium Access Control [0065] N New Radio

[0066] PDCP Packet Data Convergence Protocol

[0067] PDU Protocol Data Unit

[0068] PHY Physical

[0069] RLC Radio Link Control

[0070] SDU Service Data Unit

[0071] SN Sequence Number

[0072] TCP Transmission Control Protocol

[0073] UE User Equipment

[0074] UM Unacknowledged Mode

[0075] According to a first embodiment, a method may include transmitting, by a first higher-level protocol entity, a service data unit within a packet data unit to a first lower- level protocol entity. The method may also include transmitting, by the first higher-level protocol entity to the first lower-level protocol entity, an indication for discarding the packet data unit. In addition, the method may include receiving, by the first higher-level protocol entity, a response to the indication from the first lower-level protocol entity. Further, based on the response or lack of response, the method may include transmitting, by the first higher-level protocol entity to a second higher-level protocol entity, an instruction not to wait for reception of the service data unit.

[0076] In a variant, the first higher- level protocol entity and the first lower- level protocol entity may be in a first apparatus, and the second higher-level protocol entity may be in a second apparatus.

[0077] In a further variant, the first apparatus and/or the second apparatus may be user equipment, an evolved Node B, or a base station.

[0078] In a variant, the first higher-level protocol entity may be in a first apparatus, the first lower-level protocol entity may be in a second apparatus, and the second higher- level protocol entity may be in a third apparatus.

[0079] In a further variant, the first apparatus, the second apparatus, and/or the third apparatus may be user equipment, an evolved Node B, or a base station.

[0080] In a variant, the first lower-level protocol entity may be a radio link control ( LC) protocol.

[0081] In a variant, the first higher-level protocol entity may be a packet data convergence protocol (PDCP) protocol.

[0082] In a variant, the second higher-level protocol entity may be a packet data convergence protocol (PDCP) protocol.

[0083] In a variant, the response may include an indication indicating whether the second higher-level protocol entity may receive the packet data unit.

[0084] In a variant, the indication not to wait for the service data unit includes a sequence number.

[0085] In a further variant, the sequence number is a count value.

[0086] According to a second embodiment, a method may include receiving, by a first lower-level protocol entity, a service data unit from a first higher-level protocol entity. The method may further include receiving, by the first lower-level protocol entity from the first higher-level protocol entity, an indication for discarding the service data unit. The method may further include, in response to receiving the indication for discarding the service data unit, transmitting, by the first lower-level protocol entity, a response to the first higher-level protocol entity, wherein the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

[0087] In a variant, the first higher- level protocol entity and the first lower- level protocol entity are may be in a first apparatus, and the second higher-level protocol entity may be in a second apparatus.

[0088] In a further variant, the first apparatus and/or the second apparatus may be user equipment, an evolved Node B, or a base station.

[0089] In a variant, the first higher-level protocol entity may be in a first apparatus, the first lower-level protocol entity may be in a second apparatus, and the second higher- level protocol entity may be in a third apparatus.

[0090] In a further variant, the first apparatus, the second apparatus, and/or the third apparatus may be user equipment, an evolved Node B, or a base station.

[0091] In a variant, the first lower-level protocol entity may include a radio link control ( LC) protocol.

[0092] In a variant, the first higher-level protocol entity may include a packet data convergence protocol (PDCP) protocol.

[0093] In a further variant, the second higher-level protocol entity may include a packet data convergence protocol (PDCP) protocol.

[0094] In a variant, the response may include an indication indicating whether the second higher-level protocol entity may receive the service data unit.

[0095] In a variant, the indication for discarding the service data unit includes a sequence number.

[0096] In a further variant, the sequence number is a count value.

[0097] According to a third embodiment and a fourth embodiment, an apparatus can include at least one processor and at least one memory and computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform a method according to the first embodiment and the second embodiment, and any of its variants.

[0098] According a fifth embodiment and a sixth embodiment, an apparatus can include means for performing the method according to the first embodiment and the second embodiment, and any of its variants.

[0099] According to a seventh embodiment and an eighth embodiment, a computer program product may encode instructions for performing a process including a method according to the first embodiment and the second embodiment, and any of its variants.

[0100] According to a ninth embodiment and a tenth embodiment, a non-transitory computer-readable medium may encode instructions that, when executed in hardware, perform a process including a method according to the first embodiment and the second embodiment, and any of its variants.

[0101] According to an eleventh embodiment and a twelfth embodiment, a computer program code may include instructions for performing a method according to the first embodiment and the second embodiment, and any of its variants.

Claims

WE CLAIM:

1. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

transmit a service data unit within a packet data unit to a first lower- level protocol entity;

transmit an indication for discarding the packet data unit;

receive a response to the indication from the first lower-level protocol entity; and based on the response or lack of response, transmit to a second higher-level protocol entity an instruction not to wait for reception of the service data unit.

2. The apparatus according to claim 1, wherein the first lower-level protocol entity comprises a radio link control ( LC) protocol.

3. The apparatus according to any of claims 1 and 2, wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

4. The apparatus according to any of claims 1-3, wherein the second higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

5. The apparatus according to any of claims 1-4, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher-level protocol entity.

6. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

receive a service data unit from a first higher- level protocol entity;

receive an indication for discarding the service data unit; and

in response to receiving the indication for discarding the service data unit, transmit a response to the first higher-level protocol entity, wherein

the response is used to determine whether to send an instruction to a second higher-level protocol entity not to wait for reception of the service data unit.

7. The apparatus according to claim 6, wherein the first lower-level protocol entity comprises a radio link control ( LC) protocol.

8. The apparatus according to any of claims 6 and 7, wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

9. The apparatus according to any of claims 6-8, wherein the second higher-level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

10. The apparatus according to any of claims 6-9, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher- level protocol entity.

11. An apparatus, comprising:

means for transmitting a service data unit within a packet data unit to a first lower-level protocol entity;

means for transmitting an indication for discarding the packet data unit;

means for receiving a response to the indication from the first lower-level protocol entity; and

based on the response or lack of response, means for transmitting to a second higher-level protocol entity an instruction not to wait for reception of the service data unit.

12. The apparatus according to claim 11, wherein the first lower-level protocol entity comprises a radio link control ( LC) protocol.

13. The apparatus according to any of claims 1 1 and 12, wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

14. The apparatus according to any of claims 11-13, wherein the second higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

15. The apparatus according to any of claims 1 1-14, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher- level protocol entity.

16. An apparatus, comprising:

means for receiving a service data unit from a first higher- level protocol entity; means for receiving an indication for discarding the service data unit; and means for, in response to receiving the indication for discarding the service data unit, transmitting a response to the first higher-level protocol entity, wherein

17. The apparatus according to claim 16, wherein the first lower-level protocol entity comprises a radio link control ( LC) protocol.

18. The apparatus according to any of claims 16 and 17, wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

19. The apparatus according to any of claims 16-18, wherein the second higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

20. The apparatus according to any of claims 16-19, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher- level protocol entity.

21. A method, comprising:

transmitting, by a first higher-level protocol entity, a service data unit within a packet data unit to a first lower-level protocol entity;

transmitting, by the first higher-level protocol entity to the first lower-level protocol entity, an indication for discarding the packet data unit;

receiving, by the first higher-level protocol entity, a response to the indication from the first lower-level protocol entity; and

based on the response or lack of response, transmitting, by the first higher-level protocol entity to a second higher-level protocol entity, an instruction not to wait for reception of the service data unit.

22. The method according to claim 21, wherein the first higher- level protocol entity and the first lower-level protocol entity are in a first apparatus, and the second higher-level protocol entity are in a second apparatus.

23. The method according to any of claims 21 and 22, wherein the first higher- level protocol entity are in a first apparatus, the first lower-level protocol entity are in a second apparatus, and the second higher-level protocol entity are in a third apparatus.

24. The method according to any of claims 21-23, wherein the first lower- level protocol entity comprises a radio link control ( LC) protocol.

25. The method according to any of claims 21-24, wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

26. The method according to any of claims 21-25, wherein the second higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

27. The method according to any of claims 21-26, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher- level protocol entity.

28. A method, comprising:

receiving, by a first lower-level protocol entity, a service data unit from a first higher-level protocol entity;

receiving, by the first lower-level protocol entity from the first higher-level protocol entity, an indication for discarding the service data unit; and

in response to receiving the indication for discarding the service data unit, transmitting, by the first lower-level protocol entity, a response to the first higher-level protocol entity, wherein

29. The method according to claim 28, wherein the first higher-level protocol entity and the first lower-level protocol entity are in a first apparatus, and the second higher-level protocol entity in a second apparatus.

30. The method according to any of claims 28 and 29, wherein the first higher- level protocol entity are in a first apparatus, the first lower-level protocol entity are in a second apparatus, and the second higher-level protocol entity are in a third apparatus.

31. The method according to any of claims 28-30, wherein the first lower- level protocol entity comprises a radio link control ( LC) protocol.

32. The method according to any of claims 28-31 , wherein the first higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

33. The method according to any of claims 28-32, wherein the second higher- level protocol entity comprises a packet data convergence protocol (PDCP) protocol.

34. The method according to any of claims 28-33, wherein the response comprises an indication indicating whether a transmission of the packet data unit is available to be received by the second higher- level protocol entity.