Avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies

Abstract

Methods, systems, and apparatus for wireless communications are described. The method includes receiving control signaling that configures a UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received for requesting packet retransmission; monitoring one or more transmissions comprising at least a subset of packets in the sequence of packets; and, before expiration of the retransmission request time duration, transmitting a first retransmission request requesting retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 984,148, filed on March 2, 2020, by Balasubramanian et al., entitled “AVOIDING PACKET DATA CONVERGENCE PROTOCOL HOLES FOR BEARER IN DUAL CONNECTIVITY MODE ACROSS MULTIPLE RADIO ACCESS TECHNOLOGIES,” and U.S. Provisional Patent Application No. 62 / 984,148, filed on March 2, 2020, by Balasubramanian et al., entitled “AVOIDING PACKET DATA CONVERGENCE PROTOCOL HOLES FOR BEARER IN DUAL CONNECTIVITY MODE ACROSS MULTIPLE RADIO ACCESS TECHNOLOGIES (AVOIDING PACKET DATA CONVERGENCE PROTOCOL HOLES FOR BEARERS IN DUAL CONNECTIVITY MODE ACROSS MULTIPLE RADIO ACCESS TECHNOLOGIES)"; each of which is assigned to the assignee of the present application. Technical Field

[0003] The following relates generally to wireless communications and, more particularly, to avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies.

[0004] background

[0005] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, and the like. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems (such as long term evolution (LTE) systems, advanced LTE (LTE-A) systems, or LTE-A Pro systems), and fifth generation (5G) systems, which may be referred to as new radio (NR) systems. These systems may employ various technologies, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting communication with multiple communication devices, which may be further referred to as user equipment (UE).

[0006] In some examples, the UE may not receive all packets from a sequence of packets. In some examples, the UE may have an allotted time to request retransmission of lost packets. However, the UE may not receive every requested packet within the allotted time, which may result in delays, errors, etc., leading to a poor user experience.

[0007] Overview

[0008] The described techniques relate to improved methods, systems, devices, and apparatuses for supporting the avoidance of packet data convergence protocol holes for bearers. Generally, the described techniques address downlink data throughput issues caused by packet data holes in downlink data received by a user equipment. These techniques may include a UE receiving control signaling from one or more base stations. In some examples, the UE may operate in a dual connectivity mode across multiple radio access technologies. The control signaling may include configuration information that configures the UE to have a retransmission request time duration. When the UE determines that a packet from a packet sequence was not successfully received (e.g., the packet was not received or the packet was partially received), the UE may use the retransmission request time duration to request a retransmission of the packet. These techniques may include the UE monitoring one or more transmissions from one or more base stations. In some examples, the transmission may include at least a subset of the packets in the packet sequence. These techniques may include the UE transmitting a first retransmission request to the one or more base stations before expiration of the retransmission request time duration. In some examples, the first retransmission request may include a request for retransmission of at least one packet lost in the packet sequence. In some examples, the UE may transmit the first retransmission request based on the UE determining that a first retransmission trigger has been satisfied.

[0009] A method of wireless communication at a UE is described. The method may include receiving control signaling that configures the UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received for requesting packet retransmission; monitoring one or more transmissions comprising at least a subset of packets in the sequence of packets; and, before expiration of the retransmission request time duration, transmitting a first retransmission request requesting retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied.

[0010] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to: receive control signaling that configures the UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets is determined to be unsuccessfully received for requesting packet retransmission; monitor one or more transmissions comprising at least a subset of packets in the sequence of packets; and, before expiration of the retransmission request time duration, transmit a first retransmission request to request retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied.

[0011] Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving control signaling that configures the UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received for requesting packet retransmission; monitoring one or more transmissions comprising at least a subset of the packets in the sequence of packets; and, before expiration of the retransmission request time duration, transmitting a first retransmission request requesting retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied.

[0012] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: receive control signaling that configures the UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets is determined to have not been successfully received for requesting packet retransmission; monitor one or more transmissions comprising at least a subset of packets in the sequence of packets; and, before expiration of the retransmission request time duration, transmit a first retransmission request requesting retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied.

[0013] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, transmitting a first retransmission request may include operations, features, apparatus, or instructions for transmitting a first retransmission request based on a first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of a retransmission request time duration, or a first remaining amount or a first remaining percentage of a retransmission request time duration.

[0014] Some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for transmitting a second retransmission request based on a second retransmission trigger being satisfied before expiration of a retransmission request time duration and after a first retransmission request.

[0015] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, transmitting a second retransmission request may include operations, features, apparatus, or instructions for the following actions: transmitting a second retransmission request based on a second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, wherein the second remaining amount or the second remaining percentage may be less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger.

[0016] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for establishing a first connection with a first base station via a first radio access technology and establishing a second connection with a second base station via a second radio access technology, wherein a first transmission of the one or more transmissions may be received from the first base station and a second transmission of the one or more transmissions may be received from the second base station.

[0017] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a first retransmission request to the first base station based on the first transmission including the at least one packet.

[0018] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a first retransmission request to a second base station based on the second transmission including the at least one packet.

[0019] Some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for transmitting a first retransmission request to a first base station based on the first transmission including the at least one packet, and transmitting a second retransmission request to a second base station based on the second transmission from the second base station including a second packet in the at least one packet.

[0020] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, receiving control signaling to configure the UE to have a retransmission request prohibit time duration may include operations, features, apparatus, or instructions for the following actions: receiving control signaling to configure the UE to have a retransmission request prohibit time duration, wherein a first retransmission request may be transmitted before expiration of the retransmission request prohibit time duration.

[0021] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, receiving control signaling that configures a UE to have a retransmission request time duration may include operations, features, apparatus, or instructions for the following actions: receiving control signaling that configures the UE to have a retransmission request inhibit time duration relative to a time at which a prior retransmission request can be transmitted, the retransmission request inhibit time duration inhibiting the transmission of a next retransmission request.

[0022] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, receiving control signaling to configure a UE to have a retransmission request time duration may include operations, features, apparatuses, or instructions for the following actions: receiving first control signaling from a first base station to configure the UE to have a first retransmission request time duration, and receiving second control signaling from a second base station to configure the UE to have a second retransmission request time duration that is different from the first retransmission request time duration.

[0023] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, transmitting a first retransmission request may include operations, features, apparatus, or instructions for transmitting the first retransmission request based on a first retransmission trigger, which may be that the amount of remaining available memory in the buffer satisfies a first memory threshold.

[0024] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: switching from a first feedback mode to a second feedback mode based on a first retransmission trigger, wherein the first retransmission trigger may be that the remaining time of the retransmission request time duration satisfies a first remaining time threshold, or may be that the remaining available memory amount in the buffer satisfies a first memory threshold.

[0025] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for switching back to the first feedback mode based on the remaining available memory amount of the buffer not satisfying the first memory threshold.

[0026] In some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein, the second feedback mode configures the UE to transmit retransmission requests at a higher rate than in the first feedback mode.

[0027] Some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for transmitting, before expiration of a retransmission request time period and after a first retransmission request, a second retransmission request based on a second retransmission trigger being satisfied, wherein the second retransmission trigger may be triggered based on the amount of remaining available memory in the buffer satisfying a second memory threshold, which may be less than a first memory threshold associated with the first retransmission trigger.

[0028] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for switching from the third feedback mode back to the second feedback mode based on the remaining available memory amount of the buffer not satisfying the second memory threshold.

[0029] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, the first retransmission request includes a status protocol data unit indicating the at least one packet.

[0030] In some examples of the methods, apparatus (devices), and non-transitory computer-readable media described herein, the first retransmission request indicates a radio link control sequence number of a packet of the at least one packet. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1

[0014] An example of a system for wireless communications in accordance with aspects of the present disclosure is illustrated.

[0033] Figure 2 Examples of environments according to aspects of the present disclosure are illustrated.

[0034] Figure 3 Examples of environments according to aspects of the present disclosure are illustrated.

[0035] Figure 4 Examples of flow diagrams according to aspects of the present disclosure are illustrated.

[0036] Figure 5 Examples of flow diagrams according to aspects of the present disclosure are illustrated.

[0037] Figure 6 and 7 A block diagram of a device according to aspects of the present disclosure is shown.

[0038] Figure 8A block diagram of a communications manager according to aspects of the present disclosure is shown.

[0039] Figure 9 A diagram of a system including devices according to aspects of the present disclosure is shown.

[0040] Figure 10 and 11 A flow chart illustrating a method according to aspects of the present disclosure is shown.

[0041] Detailed description

[0042] In dual connectivity, a packet data convergence protocol (PDCP) receiver entity (e.g., a new radio (NR) PDCP receiver entity, a user equipment, etc.) can be served by two downlink (DL) radio link control (RLC) transmitter entities (e.g., two base stations using one or more radio access technologies). In some examples, the dual connectivity may include Evolved Universal Terrestrial Radio Access Network (E-UTRAN) New Radio Dual Connectivity (ENDC), or Evolved Universal Mobile Telecommunications Service Terrestrial Radio Access Network Dual Connectivity (NEDC), or New Radio Dual Connectivity (NRDC), or any combination thereof.

[0043] In some examples, a PDCP receiver entity (such as a user equipment (UE)) may be configured with one or more PDCP timers (e.g., a common reordering (t-reordering) timer). The network (e.g., a base station) may configure the UE with a reordering timer (e.g., in milliseconds), a reassembly (t-reassembly) timer (e.g., in milliseconds), a prohibit timer (e.g., in milliseconds), or any combination thereof. In some examples, the reordering timer may be used by the receiving side of the RLC entity to detect loss of RLC PDUs at lower layers. In some cases, the RLC entity may be associated with one or more RLC timers (e.g., a status prohibit (t-statusProhibit) timer, a reassembly timer in NR communications of the RLC entity, a reordering timer in LTE communications of the RLC entity, etc.). In some examples, the reassembly timer may be used by the receiving side of the RLC entity to detect loss of RLC PDUs at lower layers. In some examples, the prohibit timer may be used by the receiving side of the RLC entity to prohibit transmission of status packet data units. In some examples, at least one of the one or more timers may specify a duration for a PDCP receiving entity to wait for a lost packet (e.g., a partially received packet, a lost or partially received protocol data unit (PDU), etc.). In some examples, when at least one of the one or more timers expires or has elapsed, the PDCP receiving entity may ignore the lost PDU and pass the received packet (e.g., a packet received before or after the lost packet) to an upper layer (e.g., a radio link layer, a media access control layer, a physical layer, etc.) of the PDCP receiving entity. In some examples, the lost packet may result in a duplicate acknowledgment (DUP ACK), such as a Transmission Control Protocol (TCP) DUP ACK. In some examples, the DUP ACK may result in a reduction in the TCP window, which may reduce DL data throughput, which may result in a negative user experience.

[0044] In some examples, packet loss at the application layer may occur when one or more RLC entities do not recover from a packet data hole before a PDCP timer expires. In some systems, an RLC receiving entity may wait until a reassembly timer associated with NR communications expires or a reordering timer associated with LTE communications expires, and wait until an inhibit timer (e.g., a status inhibit timer of the RLC entity) is not running, before generating a new status PDU (e.g., a status PDU or retransmission request that includes a sequence number (SN) of each lost packet). However, the techniques described herein enable an RLC receiving entity to recover from lost packets relatively quickly compared to these other systems. The described techniques reduce the likelihood of dropped packets by eliminating the constraints that require an RLC receiving entity to wait for an RLC timer to expire and wait until an inhibit timer is not running before transmitting a status PDU with the SN of the lost packet. Thus, the techniques described herein reduce the likelihood of packet loss at the application layer and, therefore, reduce the likelihood of a poor user experience due to lost or dropped packets. Note that "lost packets" may refer to packets not transmitted by the RLC transmitting entity, or packets not received by the PDCP receiving entity, or packets partially received by the PDCP transmitting entity, or damaged packets at least partially received by the PDCC receiving entity, or any combination thereof.

[0045] In some examples, the PDCP receiving entity may request at least one of the RLC entities to perform a second-level negative acknowledgement (NACK) feedback mode (e.g., a fast NACK mode) based on the PDCP receiving entity determining that one or more second-level triggers are satisfied, where the first-level NACK feedback mode may be a default NACK feedback mode (e.g., a default NACK feedback mode that transmits a NACK or a status PDU or both based on an RLC timer configured by the network). In some examples, the one or more second-level triggers used to determine whether to initiate or terminate the second-level NACK feedback mode may include, but are not limited to, an amount of PDUs buffered in a PDCP reordering window. Examples of one or more second level triggers may include the buffered percentage of the window (e.g., 80% buffered), or the unbuffered percentage (e.g., 20% unbuffered), or the amount of megabytes (MB) buffered in the window (e.g., 8MB buffered in a 16MB window), or the amount of memory remaining in the PDCP reordering window (e.g., 8MB remaining), or the amount of PDCP timer elapsed (e.g., 15 milliseconds (ms) elapsed), or the percentage of PDCP timer elapsed (e.g., 50% elapsed), or the amount of time remaining on the PDCP timer (e.g., 15 ms remaining), or the percentage of the timer remaining (e.g., 50% timer remaining), etc., or any combination thereof.

[0046] In some examples, when the PDCP receiving entity enters a second level NACK mode (e.g., activates a second level NACK feedback mode in at least one of the one or more RLC entities), the RLC receiving entity may generate a status PDU indicating a missing SN. After generating the status PDU, the RLC receiving entity may transmit the status PDU to at least one of the RLC entities. In some examples, the second level NACK feedback mode (e.g., fast NACK mode) may overwrite one or more RLC timers configured by the network (e.g., a reassembly timer, an inhibit timer, etc.) with a modified timer value (e.g., a fixed smaller value, a fraction of a network-configured RLC timer, a percentage of a network-configured PDCP timer, etc.). In some examples, upon activation of a second level NACK feedback mode (e.g., a fast NACK mode) in an RLC entity, the RLC receiving entity may: 1) construct (e.g., immediately upon activation of the second level NACK feedback mode) a status PDU indicating the missing SN and send it to lower layers for transmission to the transmitter, and 2) overwrite a timer governing ARQ to a value less than a value configured by the network (NW) (which may be a value configured by the NW) or a fixed smaller value determined based on the HARQ configuration of the RAT used to previously transmit the missing SN. In some examples, the selection of one or more timer values ​​may be determined by the NACK feedback mode (e.g., fast NACK level, severity of fast NACK level trigger, satisfaction of one or more second level triggers, satisfaction of one or more third level triggers, etc.). In some examples, the selection of one or more timer values ​​for the second NACK feedback mode can be a percentage of a network-configured value (e.g., 50%), and further moved to a smaller fixed value in another NACK feedback mode (e.g., emergency fast NACK mode) when a hole in the PDCP causes the window size (e.g., in megabytes (MB)) to approach an upper limit of the window size or a timer (e.g., reordering) may expire soon.

[0047] In some examples, the modified timer value may be modified based on a radio access technology associated with the RLC entity. In some examples, the PDCP receiving entity may use a first fixed smaller value for a first RLC timer associated with a first RLC entity that uses a first radio access technology, and may use a second fixed smaller value (e.g., a second fixed smaller value different from the first fixed smaller value) for a second RLC timer associated with a second RLC entity that uses a second radio access technology different from the first radio access technology.

[0048] In some examples, the PDCP receiving entity may request at least one of the RLC entities to perform a third level NACK feedback mode (e.g., an emergency NACK feedback mode) based on the PDCP receiving entity determining that one or more third level triggers are satisfied. In some examples, the one or more third level triggers used to determine whether to initiate or terminate the third level NACK feedback mode may include, but are not limited to, the amount of PDUs buffered in the PDCP reordering window. Examples of the one or more third level triggers may include a buffered percentage of the window (e.g., 80% buffered), an unbuffered percentage (e.g., 20% unbuffered), an amount of the window buffered (e.g., 8MB buffered in a 16MB window), an amount of memory remaining in the PDCP reordering window (e.g., 3.2MB remaining), an amount of time that has elapsed on a PDCP timer (e.g., a common PDCP reordering timer) (e.g., 24ms elapsed), an elapsed percentage of a PDCP timer (e.g., 80% elapsed), an amount of time remaining on a PDCP timer (e.g., 6ms remaining), a percentage of the timer remaining (e.g., 20% of the timer remaining), or the like, or any combination thereof.

[0049] Aspects of the present disclosure are initially described in the context of a wireless communication system. Aspects of the present disclosure are further described in the context of a wireless communication environment. Aspects of the present disclosure are further described in the context of a flow chart. Aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow charts related to avoiding Packet Data Convergence Protocol holes for bearers in dual connectivity mode across multiple radio access technologies.

[0050] Figure 1 An example of a wireless communication system 100 that supports avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with various aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable (e.g., mission-critical) communication, low-latency communication, communication with low-cost and low-complexity devices, or any combination thereof.

[0051] Base stations 105 may be dispersed throughout a geographic area to form wireless communication system 100 and may be different forms of devices or devices with different capabilities. Base stations 105 and UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which UEs 115 and base stations 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographic area over which base stations 105 and UEs 115 may support signal communication according to one or more radio access technologies.

[0052] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be different forms of devices or devices with different capabilities. Figure 1 1. The UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relays, integrated access and backhaul (IAB) nodes, or other network equipment), such as Figure 1 As shown in .

[0053] Each base station 105 can communicate with the core network 130, with each other, or both. For example, the base stations 105 can interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 can communicate with each other directly (e.g., directly between the base stations 105), indirectly (e.g., via the core network 130), or both directly and indirectly on the backhaul links 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul links 120 can be or include one or more wireless links.

[0054] One or more of the base stations 105 described herein may include or may be referred to by one of ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a Home Node B, a Home Evolved Node B, or other suitable terminology.

[0055] UE 115 may include or be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where "device" may also be referred to as a unit, a station, a terminal, or a client, etc. UE 115 may also include or be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various objects, such as appliances or vehicles, meters, etc.

[0056] The UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as base stations 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc. Figure 1 As shown in .

[0057] The UE 115 and the base station 105 may communicate wirelessly with each other via one or more communication links 125 on one or more carriers. The term "carrier" may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operation, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0058] The signal waveform transmitted on the carrier may include multiple subcarriers (e.g., using a multicarrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may include one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the code rate of the modulation scheme, or both). Thus, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 can be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further improve the data rate or data integrity of communications with UE 115.

[0059] The time interval of the base station 105 or the UE 115 can be expressed as a multiple of a basic time unit, which can be, for example, a sampling period T s =1 / (Δf max Nf) seconds, where Δf max Nf may represent the maximum supported subcarrier spacing, while Nf may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of communication resources may be organized according to radio frames, each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0060] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, the frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of codeword periods (e.g., depending on the length of the cyclic prefix added before each codeword period). In some wireless communication systems 100, the time slot may be further divided into a plurality of mini-time slots containing one or more codewords. Excluding the cyclic prefix, each codeword period may include one or more (e.g., Nf) sampling periods. The duration of the codeword period may depend on the subcarrier spacing or the operating frequency band.

[0061] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0062] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for physical control channels may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of a carrier. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more of UEs 115 may monitor or search the control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0063] Each base station 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used to communicate with a base station 105 (e.g., on a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) used to distinguish between adjacent cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) on which the logical communication entity operates. The scope of such a cell may range from a smaller area (e.g., a structure, a subset of structures) to a larger area depending on various factors (such as the capabilities of the base station 105). For example, a cell may be or include a building, a subset of buildings, or an external space between or overlapping geographic coverage areas 110, among other examples.

[0064] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access to UEs 115 that have a service subscription with a network provider that supports the macro cell. A small cell may be associated with a lower power base station 105 (compared to a macro cell), and the small cell may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to UEs 115 that have a service subscription with the network provider, or may provide restricted access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). A base station 105 may support one or more cells and may also support communications over one or more cells using one or more component carriers.

[0065] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access to different types of devices.

[0066] In some examples, base stations 105 can be mobile and, therefore, provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies can overlap, but the different geographic coverage areas 110 can be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies can be supported by different base stations 105. The wireless communication system 100 can include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0067] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. The UE 115 can be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication and can be supported by one or more mission-critical services such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions can include prioritization of services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably herein.

[0068] In some examples, UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of base station 105 or otherwise unable to receive transmissions from base station 105. In some examples, groups of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 transmits to every other UE 115 in the group. In some examples, base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving base station 105.

[0069] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), and the EPC or 5GC may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) that routes packets or interconnects to external networks. The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the core network 130. User IP packets may be delivered through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to the network operator IP service 150. Operator IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0070] Some network devices (such as base stations 105) may include subcomponents, such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with each UE 115 through one or more other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., base station 105).

[0071] The wireless communication system 100 can operate using one or more frequency bands that can range from 300 megahertz (MHz) to 300 gigahertz (GHz). Generally speaking, the 300 MHz to 3 GHz region is referred to as the ultra-high frequency (UHF) region or the decimeter band because the wavelengths range from approximately 1 decimeter to 1 meter long. UHF waves can be blocked or redirected by buildings and environmental features, but these waves can penetrate various structures sufficiently for macrocells to provide service to UEs 115 located indoors. Transmissions using UHF waves can be associated with smaller antennas and a shorter range (e.g., less than 100 kilometers) compared to transmissions using the lower frequencies and longer wavelengths in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0072] The wireless communication system 100 may also operate in the super high frequency (SHF) region of the frequency band from 3 GHz to 30 GHz (also known as the centimeter band) or in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also known as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of the corresponding devices may be smaller and more closely spaced than the UHF antennas. In some examples, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and a shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the use of frequency bands specified across these frequency regions may vary by country or regulatory agency.

[0073] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ licensed assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band, such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices (such as base stations 105 and UEs 115) may employ carrier sensing for conflict detection and avoidance. In some examples, operations in the unlicensed band may be based on a carrier aggregation configuration (e.g., LAA) in coordination with component carriers operating in the licensed band. Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among others.

[0074] The base station 105 or UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels that can support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly (such as an antenna tower). In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having several rows and columns of antenna ports that the base station 105 can use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted via the antenna ports.

[0075] The base station 105 or the UE 115 can use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such a technique may be referred to as spatial multiplexing. For example, a transmitting device may transmit multiple signals via different antennas or different antenna combinations. Similarly, a receiving device may receive multiple signals via different antennas or different antenna combinations. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0076] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., base station 105, UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via antenna elements of an antenna array so that some signals propagating at a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with that device. The adjustments associated with each antenna element can be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0077] The base station 105 or the UE 115 may use beam sweeping techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by the base station 105 in different directions. For example, the base station 105 may transmit signals according to different sets of beamforming weights associated with different transmission directions. The transmissions in different beam directions may be used (e.g., by a transmitting device (such as the base station 105) or a receiving device (such as the UE 115)) to identify a beam direction for later transmission or reception by the base station 105.

[0078] Some signals, such as data signals associated with a particular recipient device, may be transmitted by base station 105 in a single beam direction, e.g., a direction associated with a recipient device, such as UE 115. In some examples, a beam direction associated with transmissions along a single beam direction may be determined based on signals transmitted in one or more beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions and may report to base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0079] In some examples, transmission by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may be precoded or uncoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may use similar techniques to transmit signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115) or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0080] A receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105. For example, the receiving device may attempt multiple receive directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array (e.g., different directional listening weight sets), or processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receive configurations or receive directions. In some examples, the receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving data signals). The single receive configuration may be aligned on a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0081] The wireless communication system 100 can be a packet-based network that operates according to a layered protocol stack. In the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer can be IP-based. The radio link control (RLC) layer can perform packet segmentation and reassembly to communicate on the logical channel. The media access control (MAC) layer can perform priority handling and multiplex the logical channel into the transport channel. The MAC layer can also use error detection technology, error correction technology, or both to support retransmission of the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection of the radio bearer that supports user plane data between the UE 115 and the base station 105 or the core network 130. In the physical layer, the transport channel can be mapped to the physical channel.

[0082] UE 115 and base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. Hybrid Automatic Repeat Request (HARQ) feedback is a technique for increasing the likelihood that data is correctly received on communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve MAC layer throughput in poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, a device may support simultaneous slot HARQ feedback, wherein the device may provide HARQ feedback in a particular time slot for data received in a previous symbol in that time slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or based on some other time interval.

[0083] In some examples, UE 115 may receive control signaling from one or more base stations 105. The control signaling may include configuration information that configures UE 115 to have a retransmission request time duration. When UE 115 determines that a packet from a packet sequence was not successfully received (e.g., the packet was not received or the packet was partially received), UE 115 may use the retransmission request time duration to request a retransmission of the packet. These techniques may include UE 115 monitoring one or more transmissions from one or more base stations 105. In some examples, the transmission may include at least a subset of the packets in the packet sequence. These techniques may include UE 115 transmitting a first retransmission request to one or more base stations 105 before expiration of the retransmission request time duration. In some examples, the first retransmission request may include a request for retransmission of at least one packet lost in the packet sequence. In some examples, UE 115 may transmit the first retransmission request based on UE 115 determining that a first retransmission trigger is satisfied.

[0084] By including or configuring UE 115, UE 115 can support techniques for reducing the time required to recover lost packets to avoid Packet Data Convergence Protocol holes. By avoiding Packet Data Convergence Protocol holes, UE 115 reduces packet loss, thereby improving network efficiency and user experience.

[0085] Figure 2 An example of an environment 200 that supports avoiding Packet Data Convergence Protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure is illustrated. In some examples, environment 200 can implement aspects of wireless communication system 100.

[0086] UE 115-a may be from Figure 1An example of a UE 115. In some examples, UE 115-a may be an example of a multi-SIM device. In some examples, UE 115-a may be configured to establish or request establishment of a communication link 125-a with base station 105-b. In some examples, UE 115-a may be configured to establish or request establishment of a communication link 125-b with base station 105-a. In some examples, UE 115-a may establish a first connection with base station 105-b based at least in part on a first subscription enabled by a first SIM of UE 115-a. In some examples, UE 115-a may establish a second connection (e.g., a concurrent second connection) with base station 105-b based at least in part on a second subscription enabled by a second SIM of UE 115-a.

[0087] In some examples, base station 105-a may transmit control signaling 205 to UE 115-a. In some examples, base station 105-b may transmit control signaling 210 to UE 115-a. In some examples, control signaling 205 from base station 105-a or control signaling 210 from base station 105-b may include configuration information to configure UE 115-a to have a retransmission request prohibit time duration. In some examples, the retransmission request prohibit time duration may specify that UE 115-a may transmit a status protocol data unit (PDU) when the retransmission request prohibit time duration has expired. In some examples, control signaling 205 or control signaling 210 may specify that the retransmission request prohibit time duration begins each time UE 115-a transmits a status PDU. In some examples, UE 115-a may determine that a packet from base station 105-a is lost from a first sequence of packets. In some examples, UE 115-a may determine that a packet from base station 105-b is lost from the second sequence of packets. In some examples, when UE 115-a determines that one or more packets from base station 105-a are lost from the first sequence of packets, UE 115-a may transmit a retransmission request 215 to base station 105-a before the expiration of a retransmission request prohibit time duration. In some examples, when UE 115-a determines that one or more packets from base station 105-b are lost from the second sequence of packets, UE 115-a may transmit a retransmission request 220 to base station 105-b before the expiration of a retransmission request prohibit time duration. In some examples, transmitting retransmission request 215 may include a first status PDU. In some examples, transmitting retransmission request 220 may include a second status PDU.

[0088] In some examples, UE 115-a may be configured to operate in one or more feedback modes. In some examples, when UE 115-a receives a first packet from a sequence of packets from base station 105-a or base station 105-b, UE 115-a may be configured to be in a first feedback mode (e.g., a default feedback mode). In some examples, UE 115-a may switch to a second feedback mode (e.g., a fast NACK feedback mode) based on the amount of time remaining on a timer (e.g., the amount of time remaining on a retransmission request duration) or the amount of memory remaining in a buffer, or both. In some examples, the second feedback mode may configure UE 115-a to transmit retransmission requests (e.g., retransmission request 215, retransmission request 220) at a higher rate than in the first feedback mode. In some examples, when UE 115-a is in the first feedback mode and the retransmission request prohibit time duration is active and has not expired, UE 115-a may wait to transmit retransmission request 215 to base station 105-a until the retransmission request prohibit time duration expires. In some examples, when UE 115-a is in a second feedback mode (e.g., fast NACK mode) or a second feedback mode (e.g., emergency NACK mode), and the retransmission request prohibit time duration is active and has not yet expired, UE 115-a may transmit a retransmission request 215 to base station 105-a before the expiration of the retransmission request prohibit time duration.

[0089] In some examples, control signaling 205 or control signaling 210 may include configuration information to configure UE 115-a to have a retransmission request time duration. In some examples, control signaling 205 may configure UE 115-a to have a first retransmission request time duration. In some examples, control signaling 210 may configure UE 115-a to have a second retransmission request time duration. In some examples, the second retransmission request time duration may be the same as or different from the first retransmission request time duration. In some examples, base station 105-a may use a first radio access technology. In some examples, base station 105-b may use a second radio access technology that is the same as or different from the first radio access technology. In some examples, the first retransmission request time duration may be associated with the first radio access technology, and the second retransmission request time duration may be associated with the second radio access technology. Examples of retransmission request time durations (e.g., the first retransmission request time duration indicated in control signaling 205, or the second retransmission request time duration indicated in control signaling 210, or both) may include one or more reordering time durations, or one or more reassembly time durations, or any combination thereof.

[0090] In some examples, UE 115-a may be configured to receive a first sequence of packets from base station 105-a, or UE 115-a may be configured to receive a second sequence of packets from base station 104-b, or both. In some examples, control signaling 205 or control signaling 210 may configure UE 115-a to begin a retransmission request time duration based on UE 115-a receiving the sequence of packets or based on UE 115-a determining that a packet from the sequence of packets is lost (e.g., the sequence of packets that UE 115-a received from base station 105-a or base station 105-b). In some examples, UE 115-a may determine that a packet is lost when UE 115-a determines that a sequence number of a packet in the sequence of packets is lost. In one example, when UE 115-a first receives packet 1, receives packet 2 after packet 1, and receives packet 4 after packet 2, UE 115-a may determine that packet 3 (e.g., a packet with sequence number 3) is lost.

[0091] In some examples, after starting a timer having a duration based on the retransmission request time duration, UE 115-a may switch from a first feedback mode to a second feedback mode (e.g., fast NACK feedback mode) based on the amount of time remaining on the timer (e.g., as an example, 60% or more of the retransmission request time duration has elapsed, or as an example, 40% or less of the retransmission request time duration remains). In some examples, when the amount of time remaining on the first retransmission request time duration (e.g., indicated in control signaling 205) meets a first time threshold (e.g., the elapsed time exceeds the first elapsed time threshold, or the remaining time is less than the first remaining time threshold), UE 115-a may transmit a retransmission request 215 to base station 105-a. In some examples, when the amount of time remaining in the second retransmission request time duration (e.g., indicated in control signaling 210) meets a second time threshold (e.g., the elapsed time exceeds the second elapsed time threshold, or the remaining time is less than the second remaining time threshold), UE 115-a may transmit a retransmission request 220 to base station 105-a.

[0092] In some examples, UE 115-a may switch from the first feedback mode to the second feedback mode based on an amount of memory remaining in the buffer (e.g., as an example, 60% or more of the buffer has been allocated, or as an example, 40% or less of the memory in the buffer remains available). In some examples, UE 115-a may switch from the first feedback mode to the second feedback mode based on a combination of an amount of time remaining on a timer and an amount of memory remaining in the buffer. In some examples, the buffer may store one or more packets received by UE 115-a (e.g., one or more packets from a sequence of packets).

[0093] In some examples, UE 115-a may switch from the second feedback mode to a third feedback mode (e.g., emergency NACK feedback mode) based on an amount of time remaining in the retransmission request time duration (e.g., 80% or more of the retransmission request time duration has elapsed, or 20% or less of the retransmission request time duration remains), an amount of memory remaining in the buffer (e.g., 80% or more of the buffer has been allocated, or 20% or less of the memory in the buffer remains available), or both. In some examples, control signaling 205 may indicate a first memory threshold for switching to the second feedback mode, or a second memory threshold for switching to the third feedback mode, or both. In some examples, the third feedback mode may configure UE 115-a to transmit retransmission requests (e.g., retransmission request 215, retransmission request 220) at a higher rate than in the second feedback mode or the first feedback mode.

[0094] In some examples, before expiration of the retransmission request time duration, UE 115-a may transmit a first retransmission request (e.g., retransmission request 215) to base station 105-a based on a first retransmission trigger being satisfied (e.g., at least 50% of a timer having a duration of the retransmission request time duration has elapsed, or at least 50% of memory in a buffer has been allocated). In some examples, UE 115-a may switch to a second feedback mode based on the first retransmission trigger being satisfied. In some examples, before expiration of the retransmission request time duration and after transmitting the first retransmission request (e.g., retransmission request 215) to base station 105-a, UE 115-a may transmit a second retransmission request to base station 105-a based at least in part on a second retransmission trigger of control signaling 205 being satisfied (e.g., at least 80% of a first timer having a duration of the first retransmission request time duration has elapsed, or at least 80% of memory in a buffer of UE 115-a has been allocated). In some examples, UE 115 - a may switch to a third feedback mode based on a second retransmission trigger of control signaling 205 being satisfied.

[0095] In some examples, before expiration of the retransmission request time duration and after transmitting the first retransmission request (e.g., retransmission request 220) to base station 105-b, UE 115-a may transmit a second retransmission request to base station 105-b based on a second retransmission trigger being satisfied (e.g., at least 80% of a second timer having a duration of the second retransmission request time duration has elapsed, or at least 80% of memory in a buffer of UE 115-a has been allocated) in control signaling 210. In some examples, UE 115-a may switch to the third feedback mode based on the second retransmission trigger of control signaling 210 being satisfied.

[0096] In some examples, UE 115-a may switch from the third feedback mode to the second feedback mode based on the remaining available memory amount of the buffer not satisfying the second memory threshold. For example, if the second memory threshold is satisfied when the remaining memory amount is 20% or less, or if the second memory threshold is satisfied when the remaining memory amount is less than 20%, UE 115-a may switch from the third feedback mode to the second feedback mode when the remaining available memory amount is greater than 20% of the buffer capacity or at least 20% of the memory in the buffer is unallocated.

[0097] In some examples, UE 115-a may switch from the second feedback mode to the first feedback mode based on the remaining available memory amount of the buffer not satisfying the first memory threshold. For example, in the case where the first memory threshold is satisfied when the remaining memory amount is 50% or less, or the first memory threshold is satisfied when the remaining memory amount is less than 50%, UE 115-a may switch from the second feedback mode to the first feedback mode when the remaining available memory amount is greater than 50% of the buffer capacity or at least 50% of the memory in the buffer is unallocated. In some examples, UE 115-a may switch from the third feedback mode to the second feedback mode, or from the third feedback mode to the first feedback mode, based on the elapse of a retransmission request time duration (e.g., the elapse of a timer having a duration of the retransmission request time duration).

[0098] In some examples, the first retransmission request time duration indicated in control signaling 205 includes a status protocol data unit indicating one or more lost packets in the sequence of packets from base station 105-a. In some examples, the second retransmission request time duration indicated in control signaling 210 includes a status protocol data unit indicating one or more lost packets in the sequence of packets from base station 105-b. In some examples, retransmission request 215 indicates a radio link control sequence number for each lost packet in the sequence of packets from base station 105-a. In some examples, retransmission request 220 indicates a radio link control sequence number for each lost packet in the sequence of packets from base station 105-b.

[0099] Figure 3 An example of an environment 300 that supports avoiding Packet Data Convergence Protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure is illustrated. In some examples, environment 300 can implement aspects of wireless communication system 100.

[0100] In the illustrated example, the environment 300 may include a PDCP entity 305, a first RLC entity 310, and a second RLC entity 315. Examples of the PDCP entity 305 may include Figure 1Examples of the first RLC entity 310 or the second RLC entity 315 may include Figure 1 or 2's base station 105.

[0101] As shown, the PDCP entity 305 may receive one or more packets from the first RLC entity 310 (e.g., PDCP SN 5, PDCP SN 6, PDCP SN 10, etc.). In some examples, the PDCP entity 305 may determine that the SNs of the packets received from the first RLC entity 310 were received out of sequence. For example, after receiving PDCP SN 6 from the first RLC entity 310, the PDCP entity 305 may expect to next receive PDCP SN 8 from the first RLC entity 310. However, instead, the PDCP entity 305 next receives PDCP SN 10. Accordingly, the PDCP entity 305 may determine that PDCP SN 6 is associated with the RLC SN 1 packet of the first RLC entity 310, and that PDCP SN 10 is associated with the RLC SN 3 packet of the first RLC entity 310. In some examples, the PDCP entity 305 may start a first RLC timer associated with the first RLC entity 310. In some examples, the PDCP entity 305 may monitor a first RLC timer after determining that one or more packets from the first RLC entity 310 are lost, partially received, or corrupted. In some examples, the PDCP entity 305 may monitor a buffer associated with packets received from the first RLC entity 310 after determining that one or more packets from the first RLC entity 310 are lost, partially received, or corrupted.

[0102] In some examples, when the PDCP entity 305 determines that the amount of time remaining on the first RLC timer satisfies a first timer threshold, or the amount of memory remaining in the buffer satisfies a buffer threshold, the PDCP entity 305 may generate a first retransmission request and transmit the first retransmission request to the first RLC entity 310. In some examples, the first retransmission request may indicate that an RLC SN2 packet is lost. In some examples, the PDCP entity 305 may receive the lost RLC SN2 packet from the first RLC entity 310 based on the first retransmission request. In some examples, when the PDCP entity 305 receives the lost packets from the first RLC entity 310 before the first RLC timer expires, the PDCP entity 305 may process each packet received from the first RLC entity 310 and send the processed packets to upper layers of the PDCP entity 305.

[0103] As shown, the PDCP entity 305 may receive one or more packets (e.g., PDCP SN 7, PDCP SN 11, PDCP SN 12, etc.) from the second RLC entity 315. In some examples, the PDCP entity 305 may determine that the SNs of the packets received from the second RLC entity 315 were received out of sequence. For example, after receiving PDCP SN 7 from the second RLC entity 315, the PDCP entity 305 may expect to next receive PDCP SN 9 from the second RLC entity 315. However, instead, the PDCP entity 305 next receives PDCP SN 11. Accordingly, the PDCP entity 305 may determine that PDCP SN 7 is associated with the RLC SN 20 packet of the second RLC entity 315, and that PDCP SN 11 is associated with the RLC SN 22 packet of the second RLC entity 315. In some examples, the PDCP entity 305 may start a second RLC timer associated with the second RLC entity 315. In some examples, after determining that one or more packets from the second RLC entity 315 are lost, partially received, or corrupted, the PDCP entity 305 may monitor a second RLC timer. In some examples, after determining that one or more packets from the second RLC entity 315 are lost, partially received, or corrupted, the PDCP entity 305 may monitor a buffer associated with packets received from the second RLC entity 315. In some examples, when the PDCP entity 305 determines that the amount of time remaining on the second RLC timer satisfies a second timer threshold, or the amount of memory remaining in the buffer satisfies a buffer threshold, the PDCP entity 305 may generate a second retransmission request and transmit the second retransmission request to the second RLC entity 315. In some examples, the second retransmission request may indicate that an RLC SN 21 packet is lost. In some examples, the PDCP entity 305 may receive the lost RLC SN 21 packet from the second RLC entity 315 based on the second retransmission request. In some examples, when the PDCP entity 305 receives lost packets from the second RLC entity 315 before the second RLC timer expires, the PDCP entity 305 may process each packet received from the second RLC entity 315 and send the processed packets to an upper layer of the PDCP entity 305.

[0104] Figure 4 An example of a flowchart 400 is illustrated to support avoiding Packet Data Convergence Protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure. In some examples, flowchart 400 can implement aspects of wireless communication system 100.

[0105] In the illustrated example, flowchart 400 may include base station 105-c, UE 115-b, and base station 105-d. In some examples, UE 115-b may be from Figure 1 In some examples, base station 105-c or base station 105-d may be an example of a UE 115 from Figure 1 1 or 2. In some examples, UE 115-b may be an example of a multi-SIM device. In one example, UE 115-b may be a dual-SIM dual standby (DSDS) device. In some examples, UE 115-b may establish a first connection with base station 105-c based at least in part on a first SIM of UE 115-b. In some examples, UE 115-b may establish a second connection with base station 105-d based at least in part on a second SIM of UE 115-b.

[0106] At 405, base station 105-c may transmit control signaling to UE 115-b. In some cases, the control signaling at 405 may include configuration information. In some examples, the control signaling at 405 may include an RLC timer configuration (e.g., an RLC timer duration, etc.). In some examples, the RLC timer configuration may be based on the radio access technology of base station 105-c.

[0107] At 410, base station 105-d may optionally transmit control signaling to UE 115-b. In some cases, the control signaling at 410 may include configuration information. In some examples, the control signaling at 410 may include an RLC timer configuration (e.g., an RLC timer duration, etc.). In some examples, the RLC timer configuration may be based on the radio access technology of base station 105-d.

[0108] At 415, base station 105-c may transmit data (e.g., data packets) to UE 115-b. In some examples, the data transmitted at 415 may include a sequence of data packets.

[0109] At 420, base station 105-d may optionally transmit data (e.g., data packets) to UE 115-b. In some examples, the data transmitted at 420 may include a sequence of data packets.

[0110] At 425, UE 115-b may determine that one or more packets from the data transmitted at 415 are lost, partially received, or corrupted. In some examples, UE 115-b may determine packet loss based on receiving packets out of sequence or determining that a packet with an expected sequence number has not been received.

[0111] At 430, UE 115-b may start at least one RLC timer. In some examples, the duration of the first RLC timer at 430 may be based on the control signaling received at 405. In some examples, the duration of the second RLC timer at 430 may be based on the control signaling received at 410.

[0112] At 435 , UE 115 - b may determine that x% of the RLC timers have elapsed (eg, 50% of the first RLC timer has elapsed, or 50% of the second RLC timer has elapsed, or 50% of both timers have elapsed).

[0113] At 440, UE 115-b may generate a retransmission request (e.g., a STATUS PDU) and transmit the retransmission request to base station 105-c. In some examples, UE 115-b may generate the retransmission request based on UE 115-b determining that x% of the RLC timer has elapsed. In some examples, the retransmission request may include a sequence number of the lost packet (e.g., an RLC sequence number).

[0114] At 445, the base station 105-c may transmit (e.g., retransmit) the lost packet to the UE 115-b. In some examples, the base station 105-c may retransmit the lost packet based on a sequence number included in the retransmission request.

[0115] At 450, UE 115-b may determine that each packet associated with the data at 415 is received. In some examples, UE 115-b may determine that each sequence number of a sequence of packets associated with the data at 415 is accounted for.

[0116] At 455 , UE 115 - b may determine that the RLC timer started at 430 has expired.

[0117] At 460 , UE 115 - b may process each received packet (eg, strip RLC header, etc.) and send the processed packet to upper layers of UE 115 - b (eg, RLC layer of UE 115 - b, etc.).

[0118] Figure 5 An example of a flowchart 500 is illustrated that supports avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure. In some examples, flowchart 500 can implement aspects of wireless communication system 100.

[0119] In the illustrated example, flowchart 500 may include base station 105-e, UE 115-c, and base station 105-f. In some examples, UE 115-c may be from Figure 1In some examples, base station 105-e or base station 105-f may be an example of a UE 115 from Figure 1 1 or 2. In some examples, UE 115-c may be an example of a multi-SIM device. In one example, UE 115-c may be a dual-SIM dual standby (DSDS) device. In some examples, UE 115-c may establish a first connection with base station 105-e based at least in part on a first SIM of UE 115-c. In some examples, UE 115-c may establish a second connection with base station 105-f based at least in part on a second SIM of UE 115-c.

[0120] At 505, base station 105-e may transmit control signaling to UE 115-c. In some cases, the control signaling at 505 may include configuration information. In some examples, the control signaling at 505 may include a first RLC timer configuration (e.g., a first RLC timer duration, etc.). In some examples, the first RLC timer configuration may be based on the radio access technology of base station 105-e.

[0121] At 510, base station 105-f may transmit control signaling to UE 115-c. In some cases, the control signaling at 510 may include configuration information. In some examples, the control signaling at 510 may include a second RLC timer configuration (e.g., a second RLC timer duration, etc.). In some examples, the second RLC timer configuration may be based on the radio access technology of base station 105-f.

[0122] At 515, the base station 105-e may transmit data (e.g., data packets) to the UE 115-c. In some examples, the data transmitted at 515 may include a first sequence of data packets.

[0123] At 520, the base station 105-f may transmit data (e.g., data packets) to the UE 115-c. In some examples, the data transmitted at 520 may include a second sequence of data packets.

[0124] At 525, the UE 115-c may determine that one or more packets from the data transmitted at 515 are lost, partially received, or corrupted. At 525, the UE 115-c may also determine that one or more packets from the data transmitted at 520 are lost, partially received, or corrupted. In some examples, the UE 115-c may determine packet loss based on receiving packets out of sequence or determining that a packet with an expected sequence number has not been received.

[0125] At 530, UE 115-c may start a first RLC timer and start a second RLC timer. In some examples, the duration of the first RLC timer at 530 may be based on the control signaling received at 505 (e.g., the first RLC timer for the first RLC timer duration). In some examples, the duration of the second RLC timer at 530 may be based on the control signaling received at 510 (e.g., the second RLC timer for the second RLC timer duration).

[0126] At 535, UE 115-c may determine that x% of the RLC buffer has been allocated (e.g., 50% of the RLC buffer has been allocated). In some examples, UE 115-c may determine that x% of the first RLC timer or x% of the second RLC timer has elapsed (e.g., 50% of the first RLC timer has elapsed, or 50% of the second RLC timer has elapsed, or 50% of both timers have elapsed). In some cases, UE 115-c may determine that x% of the PDCP buffer has been allocated (e.g., 50% of the PDCP buffer has been allocated).

[0127] At 540, UE 115-c may generate a first retransmission request (e.g., a first status PDU) and transmit the first retransmission request to base station 105-e. In some examples, UE 115-c may generate the first retransmission request based on UE 115-c determining that at least x% of the buffer is allocated (e.g., at least 50% of the buffer is allocated). In some examples, UE 115-c may generate the first retransmission request based on UE 115-c determining that x% of the first RLC timer has elapsed. In some examples, the first retransmission request may include a sequence number (e.g., an RLC sequence number) of the lost packet associated with the data at 515.

[0128] At 545, UE 115-c may generate a second retransmission request (e.g., a second status PDU) and transmit the second retransmission request to base station 105-f. In some examples, UE 115-c may generate the second retransmission request based on UE 115-c determining that at least x% of the buffer is allocated (e.g., at least 50% of the buffer is allocated). In some examples, UE 115-c may generate the second retransmission request based on UE 115-c determining that x% of a second RLC timer has elapsed. In some examples, the second retransmission request may include a sequence number (e.g., an RLC sequence number) of the lost packet associated with the data at 520.

[0129] At 550, the base station 105-e may transmit (e.g., retransmit) the lost packet to the UE 115-c. In some examples, the base station 105-e may retransmit the lost packet based on the sequence number included in the first retransmission request.

[0130] At 555, the UE 115-c may determine that each packet associated with the data at 515 is received. In some examples, the UE 115-c may determine that each sequence number of a sequence of packets associated with the data at 515 is accounted for.

[0131] At 560, the UE 115-c may determine that x% of the RLC buffer has been allocated (e.g., 80% of the RLC buffer has been allocated), where y is greater than x. In some examples, the UE 115-c may determine that y% of the first RLC timer or y% of the second RLC timer have elapsed (e.g., 80% of the first RLC timer has elapsed, or 80% of the second RLC timer has elapsed, or 80% of both timers have elapsed). In some cases, the UE 115-c may determine that x% of the PDCP buffer has been allocated (e.g., 80% of the PDCP buffer has been allocated), where y is greater than x.

[0132] At 565, UE 115-c may generate a third retransmission request (e.g., a third status PDU) and transmit the third retransmission request to base station 105-f. In some examples, UE 115-c may generate the third retransmission request based on UE 115-c determining that at least y% of the buffer is allocated (e.g., at least 80% of the buffer is allocated). In some examples, UE 115-c may generate the third retransmission request based on UE 115-c determining that y% of the second RLC timer has elapsed. In some examples, the third retransmission request may include a sequence number (e.g., an RLC sequence number) of the lost packet associated with the data at 520.

[0133] In some examples, UE 115-c may determine that at least two packets associated with the data at 520 are lost. In some examples, UE 115-c may receive the first of the two lost packets in response to the second retransmission request at 545. However, after determining that y% of the RLC buffer is allocated, or y% of the second RLC timer has elapsed, or both, UE 115-c may determine that the second of the two lost packets is still lost. Accordingly, UE 115-c may generate a third retransmission request to request the second of the two lost packets.

[0134] At 570, the base station 105-f may transmit (e.g., retransmit) the at least one remaining lost packet to the UE 115-c. In some examples, the base station 105-f may retransmit the lost packet based on the sequence number included in the third retransmission request.

[0135] At 575, the UE 115-c may determine that each packet associated with the data at 520 is received. In some examples, the UE 115-c may determine that each sequence number of a sequence of packets associated with the data at 520 is accounted for.

[0136] At 580 , the UE 115 - c may determine that the first RLC timer started at 530 or the second RLC timer started at 530 has expired, or both have expired.

[0137] At 585, UE 115-c may process each of the received packets associated with the data at 515 and process each of the received packets associated with the data at 520, and then send the processed packets to an upper layer of UE 115-c (e.g., an RLC layer of UE115-c, etc.).

[0138] Figure 6 A block diagram 600 is shown of a device 605 that supports avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a UE 115 as described herein. The device 605 may include a receiver 610, a communication manager 615, and a transmitter 620. The device 605 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0139] The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies, etc.). The information may be passed to other components of the device 605. The receiver 610 may be a reference to Figure 9 Examples of aspects of the described transceiver 920. The receiver 610 may utilize a single antenna or a collection of antennas.

[0140] The communication manager 615 may receive control signaling that configures the UE to have a retransmission request time duration relative to a time when a packet in a sequence of packets is determined to be unsuccessfully received for requesting packet retransmission; monitor one or more transmissions comprising at least a subset of packets in the sequence of packets; and transmit a first retransmission request requesting retransmission of at least one packet in the sequence of packets based on a first retransmission trigger being satisfied before expiration of the retransmission request time duration. The communication manager 615 may be an example of aspects of the communication manager 910 described herein.

[0141] The communication manager 615 or its subcomponents may be implemented in hardware, in code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 615 or its subcomponents may be performed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), an FPGA or other programmable logic device designed to perform the functions described in this disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0142] The communication manager 615 or its subcomponents can be physically located at various locations, including being distributed such that portions of functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 615 or its subcomponents can be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 615 or its subcomponents can be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0143] The transmitter 620 may transmit signals generated by other components of the device 605. In some examples, the transmitter 620 may be co-located with the receiver 610 in a transceiver module. For example, the transmitter 620 may be a reference Figure 9 Examples of aspects of the described transceiver 920. The transmitter 620 may utilize a single antenna or a collection of antennas.

[0144] By including or configuring the communication manager 615 according to the examples described herein, the device 605 (e.g., a processor controlling or otherwise coupled to the receiver 610, the transmitter 620, the communication manager 615, or a combination thereof) can support techniques for reducing the time required to recover lost packets to avoid packet data convergence protocol holes. By avoiding packet data convergence protocol holes, the device 605 reduces processing, reduces power consumption, and provides more efficient use of communication resources.

[0145] Figure 7 A block diagram 700 of a device 705 that supports avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure is shown. The device 705 can be an example of aspects of the device 605 or UE 115 as described herein. The device 705 may include a receiver 710, a communication manager 715, and a transmitter 735. The device 705 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0146] The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies, etc.). The information may be passed to other components of the device 705. The receiver 710 may be a reference to Figure 9 Examples of aspects of the described transceiver 920. The receiver 710 may utilize a single antenna or a collection of antennas.

[0147] Communications manager 715 may be an example of aspects of communications manager 615 as described herein. Communications manager 715 may include control manager 720, monitoring manager 725, and retransmission manager 730. Communications manager 715 may be an example of aspects of communications manager 910 as described herein.

[0148] The control manager 720 may receive control signaling that configures the UE to have a retransmission request time duration for requesting packet retransmission relative to a time when it was determined that a packet in a sequence of packets was not successfully received.

[0149] Monitoring manager 725 may monitor one or more transmissions comprising at least a subset of packets in a sequence of packets.

[0150] The retransmission manager 730 may transmit a first retransmission request to request retransmission of at least one packet in the sequence of packets based on the first retransmission trigger being satisfied before expiration of the retransmission request time duration.

[0151] The transmitter 735 may transmit signals generated by other components of the device 705. In some examples, the transmitter 735 may be co-located with the receiver 710 in a transceiver module. For example, the transmitter 735 may be a reference Figure 9 Examples of aspects of the described transceiver 920. The transmitter 735 may utilize a single antenna or a collection of antennas.

[0152] Figure 8 A block diagram 800 illustrates a communication manager 805 that supports avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with aspects of the present disclosure. The communication manager 805 can be an example of aspects of the communication manager 615, the communication manager 715, or the communication manager 910 described herein. The communication manager 805 can include a control manager 810, a monitoring manager 815, a retransmission manager 820, a connection manager 825, and a configuration manager 830. Each of these modules can communicate with each other directly or indirectly (e.g., via one or more buses).

[0153] The connection manager 825 may establish a first connection with a first base station via a first radio access technology and a second connection with a second base station via a second radio access technology, wherein a first transmission of the one or more transmissions is received from the first base station and a second transmission of the one or more transmissions is received from the second base station.

[0154] The control manager 810 may receive control signaling that configures the UE to have a retransmission request time duration for requesting packet retransmission relative to a time when it was determined that a packet in a sequence of packets was not successfully received.

[0155] In some examples, the control manager 810 may receive control signaling configuring the UE to have a retransmission request prohibit time duration, wherein the first retransmission request is transmitted prior to expiration of the retransmission request prohibit time duration.

[0156] In some examples, the control manager 810 may receive control signaling that configures the UE to have a retransmission request prohibit time duration relative to the time when the previous retransmission request was transmitted, the retransmission request prohibit time duration prohibiting the transmission of the next retransmission request. In some examples, the control manager 810 may receive first control signaling from the first base station that configures the UE to have a first retransmission request time duration.

[0157] In some examples, the control manager 810 may receive second control signaling from the second base station to configure the UE to have a second retransmission request time duration different from the first retransmission request time duration.The monitoring manager 815 may monitor one or more transmissions including at least a subset of packets in the sequence of packets.

[0158] The retransmission manager 820 may transmit a first retransmission request to request retransmission of at least one packet in the sequence of packets based on the first retransmission trigger being satisfied before expiration of the retransmission request time duration.

[0159] In some examples, the retransmission manager 820 may transmit a first retransmission request based on a first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of the retransmission request time duration, or a first remaining amount or a first remaining percentage of the retransmission request time duration.

[0160] In some examples, the retransmission manager 920 may transmit a second retransmission request before expiration of the retransmission request time duration and after the first retransmission request based on the second retransmission trigger being satisfied.

[0161] In some examples, the retransmission manager 920 may transmit a second retransmission request based on a second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, where the second remaining amount or the second remaining percentage is less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger.

[0162] In some examples, the retransmission manager 820 may transmit a first retransmission request to the first base station based on the first transmission including the at least one packet. In some examples, the retransmission manager 820 may transmit a first retransmission request to the second base station based on the second transmission including the at least one packet.

[0163] In some examples, the retransmission manager 820 may transmit a first retransmission request to the first base station based on the first transmission including the at least one packet. In some examples, the retransmission manager 820 may transmit a second retransmission request to the second base station based on the second transmission from the second base station including a second packet in the at least one packet.

[0164] In some examples, the retransmission manager 920 may transmit a first retransmission request based on a first retransmission trigger, the first retransmission trigger being that the amount of remaining available memory in the buffer satisfies a first memory threshold. In some examples, the retransmission manager 920 may transmit a second retransmission request based on a second retransmission trigger being satisfied before expiration of the retransmission request time duration and after the first retransmission request, wherein the second retransmission trigger is triggered based on the amount of remaining available memory in the buffer satisfying a second memory threshold, the second memory threshold being less than the first memory threshold associated with the first retransmission trigger.

[0165] In some cases, the first retransmission request includes a status protocol data unit indicating the at least one packet. In some cases, the first retransmission request indicates a radio link control sequence number of a packet of the at least one packet.

[0166] The configuration manager 830 may switch from the first feedback mode to the second feedback mode based on a first retransmission trigger, wherein the remaining time of the retransmission request time duration satisfies a first remaining time threshold, or the remaining available memory amount of the buffer satisfies a first memory threshold.

[0167] In some examples, the configuration manager 830 may switch back to the first feedback mode based on the amount of remaining available memory in the buffer not meeting the first memory threshold. In some examples, the configuration manager 830 may switch back from the third feedback mode to the second feedback mode based on the amount of remaining available memory in the buffer not meeting the second memory threshold. In some cases, the second feedback mode configures the UE to transmit retransmission requests at a higher rate than in the first feedback mode.

[0168] Figure 9 A block diagram 900 of a device 905 supporting avoidance of packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with various aspects of the present disclosure is shown. The device 905 may be an example of, or include components of, the device 605, device 705, or UE 115 as described herein. The device 905 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a communication manager 910, an I / O controller 915, a transceiver 920, an antenna 925, a memory 930, and a processor 940. These components may be in electronic communication via one or more buses (e.g., bus 945).

[0169] The communication manager 910 can receive control signaling that configures the UE to have a retransmission request time duration relative to a time when it is determined that a packet in a packet sequence was not successfully received for requesting packet retransmission; monitor one or more transmissions including at least a subset of packets in the packet sequence; and transmit a first retransmission request to request retransmission of at least one packet in the packet sequence based on a first retransmission trigger being satisfied before expiration of the retransmission request time duration.

[0170] I / O controller 915 can manage input and output signals for device 905. I / O controller 915 can also manage peripheral devices that are not integrated into device 905. In some cases, I / O controller 915 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 915 can utilize an operating system, such as or another known operating system. In other cases, I / O controller 915 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 915 may be implemented as part of a processor. In some cases, a user may interact with device 905 via I / O controller 915 or via hardware components controlled by I / O controller 915.

[0171] The transceiver 920 can communicate bidirectionally via one or more antennas, wired or wireless links, as described herein. For example, the transceiver 920 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 920 can also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and demodulate packets received from the antenna.

[0172] In some cases, a wireless device may include a single antenna 925. However, in some cases, the device may have more than one antenna 925, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0173] The memory 930 may include RAM and ROM. The memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, the memory 930 may include, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0174] The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks that support avoiding packet data convergence protocol holes for bearers in a dual connectivity mode across multiple radio access technologies).

[0175] The code 935 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 935 may be stored in a non-transitory computer-readable medium, such as system memory or other types of memory. In some cases, the code 935 may not be directly executed by the processor 940, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0176] By including or configuring the communication manager 910 according to the examples described herein, the device 905 can support techniques for reducing the time required to recover lost packets to avoid packet data convergence protocol holes. By avoiding packet data convergence protocol holes, the device 905 reduces packet loss, thereby achieving improved communication reliability, reduced latency, an improved user experience associated with reduced processing, reduced power consumption, more efficient use of communication resources, improved coordination between devices, longer battery life, and improved utilization of processing power.

[0177] Figure 10 A flow chart illustrating a method 1000 for supporting avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with various aspects of the present disclosure is shown. The operations of the method 1000 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of the method 1000 may be implemented by a UE 115 or components thereof as described herein. Figures 6 to 9In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described herein.

[0178] At 1005, the UE may receive control signaling that configures the UE to have a retransmission request time duration relative to the time when it is determined that a packet in the packet sequence was not successfully received for requesting packet retransmission. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be as described with reference to Figures 6 to 9 The control manager described is executed.

[0179] At 1010, the UE may monitor one or more transmissions comprising at least a subset of packets in a sequence of packets. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed as described with reference to Figures 6 to 9 The monitoring manager described is executed.

[0180] At 1015, the UE may transmit a first retransmission request to request retransmission of at least one packet in the sequence of packets based on the first retransmission trigger being satisfied before the expiration of the retransmission request time duration. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be as described with reference to Figures 6 to 9 The retransmission manager described is used to perform the

[0181] Figure 11 A flow chart illustrating a method 1100 for supporting avoiding packet data convergence protocol holes for bearers in dual connectivity mode across multiple radio access technologies in accordance with various aspects of the present disclosure is shown. The operations of the method 1100 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of the method 1100 may be implemented by a UE 115 or components thereof as described herein. Figures 6 to 9 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described herein.

[0182] At 1105, the UE may receive control signaling that configures the UE to have a retransmission request time duration relative to the time when it is determined that a packet in the packet sequence was not successfully received for requesting packet retransmission. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be as described with reference to Figures 6 to 9 The control manager described is executed.

[0183] At 1110, the UE may monitor one or more transmissions comprising at least a subset of packets in a sequence of packets. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed as described with reference to Figures 6 to 9 The monitoring manager described is executed.

[0184] At 1115, the UE may transmit a first retransmission request to request retransmission of at least one packet in the sequence of packets based on the first retransmission trigger being satisfied before the expiration of the retransmission request time duration. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be as described with reference to Figures 6 to 9 The retransmission manager described is used to perform the

[0185] At 1120, the UE may transmit a first retransmission request based on a first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of the retransmission request time duration, or a first remaining amount or a first remaining percentage of the retransmission request time duration. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed as described with reference to Figures 6 to 9 The retransmission manager described is used to perform the

[0186] At 1125, the UE may transmit a second retransmission request before the expiration of the retransmission request time duration and after the first retransmission request based on the second retransmission trigger being satisfied. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be as described with reference to Figures 6 to 9 The retransmission manager described is used to perform the

[0187] At 1130, the UE may transmit a second retransmission request based on a second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, wherein the second remaining amount or the second remaining percentage is less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed as described with reference to Figures 6 to 9 The retransmission manager described is used to perform the

[0188] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0189] The following provides an overview of various aspects of the disclosure:

[0190] Aspect 1: A method for wireless communication at a UE, comprising: receiving control signaling that configures the UE to have a retransmission request time duration relative to a time when it is determined that a packet in a packet sequence was not successfully received for requesting packet retransmission; monitoring one or more transmissions including at least a subset of packets in the packet sequence; and transmitting a first retransmission request to request retransmission of at least one packet in the packet sequence before expiration of the retransmission request time duration based at least in part on a first retransmission trigger being satisfied.

[0191] Aspect 2: A method as in Aspect 1, wherein transmitting a first retransmission request includes transmitting the first retransmission request based at least in part on a first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of the retransmission request time duration, or a first remaining amount or a first remaining percentage of the retransmission request time duration.

[0192] Aspect 3: The method of any one of aspects 1 to 2, further comprising: transmitting a second retransmission request before expiration of the retransmission request time duration and after the first retransmission request, based at least in part on a second retransmission trigger being satisfied.

[0193] Aspect 4: A method as in Aspect 3, wherein transmitting a second retransmission request includes: transmitting the second retransmission request based at least in part on a second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, wherein the second remaining amount or the second remaining percentage is less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger.

[0194] Aspect 5: The method of any one of Aspects 1 to 4 further comprises: establishing a first connection with a first base station via a first radio access technology and establishing a second connection with a second base station via a second radio access technology, wherein a first transmission in the one or more transmissions is received from the first base station and a second transmission in the one or more transmissions is received from the second base station.

[0195] Aspect 6: The method of aspect 5, further comprising: transmitting a first retransmission request to the first base station based at least in part on the first transmission including the at least one packet.

[0196] Aspect 7: The method of any one of aspects 5 to 6, further comprising: transmitting a first retransmission request to the second base station based at least in part on the second transmission including the at least one packet.

[0197] Aspect 8: The method of any one of Aspects 5 to 7 further includes: transmitting a first retransmission request to the first base station at least in part based on the first transmission including the at least one packet; and transmitting a second retransmission request to the second base station at least in part based on the second transmission from the second base station including the second packet in the at least one packet.

[0198] Aspect 9: A method as in any one of Aspects 1 to 8, wherein receiving control signaling to configure the UE to have a retransmission request time duration includes: receiving control signaling to configure the UE to have a retransmission request prohibit time duration, wherein the first retransmission request is transmitted before the expiration of the retransmission request prohibit time duration.

[0199] Aspect 10: A method as in Aspect 9, wherein receiving control signaling to configure the UE to have a retransmission request time duration includes: receiving control signaling to configure the UE to have a retransmission request prohibit time duration relative to the time when the previous retransmission request was transmitted, and the retransmission request prohibit time duration prohibits the transmission of the next retransmission request.

[0200] Aspect 11: A method as described in any one of Aspects 1 to 10, wherein receiving control signaling to configure the UE to have a retransmission request time duration includes: receiving first control signaling from a first base station to configure the UE to have a first retransmission request time duration; and receiving second control signaling from a second base station to configure the UE to have a second retransmission request time duration different from the first retransmission request time duration.

[0201] Aspect 12: The method of any one of aspects 1 to 11, wherein transmitting the first retransmission request comprises transmitting the first retransmission request based at least in part on a first retransmission trigger, the first retransmission trigger being that the amount of remaining available memory in the buffer satisfies a first memory threshold.

[0202] Aspect 13: The method of any one of Aspects 1 to 12 further includes: switching from the first feedback mode to the second feedback mode based at least in part on a first retransmission trigger, wherein the first retransmission trigger is that the remaining time of the retransmission request time duration meets a first remaining time threshold, or the remaining available memory amount of the buffer meets a first memory threshold.

[0203] Aspect 14: The method of aspect 13, further comprising: switching back to the first feedback mode based at least in part on the remaining available memory amount of the buffer not satisfying the first memory threshold.

[0204] Aspect 15: The method of any one of aspects 13 to 14, wherein the second feedback mode configures the UE to transmit retransmission requests at a higher rate than in the first feedback mode.

[0205] Aspect 16: The method of any one of Aspects 13 to 15, further comprising: transmitting a second retransmission request before expiration of the retransmission request time duration and after the first retransmission request, at least in part based on a second retransmission trigger being satisfied, wherein the second retransmission trigger is triggered at least in part based on the remaining available memory amount in the buffer satisfying a second memory threshold, which is less than a first memory threshold associated with the first retransmission trigger.

[0206] Aspect 17: The method of aspect 16, further comprising: switching from the third feedback mode back to the second feedback mode based at least in part on the remaining available memory amount of the buffer not satisfying the second memory threshold.

[0207] Aspect 18: The method of any one of Aspects 1 to 17, wherein the first retransmission request includes a status protocol data unit indicating the at least one packet.

[0208] Aspect 19: The method of any one of aspects 1 to 18, wherein the first retransmission request indicates a radio link control sequence number of a packet of the at least one packet.

[0209] Aspect 20: An apparatus for performing wireless communication at a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 1 to 19.

[0210] Aspect 21: An apparatus for wireless communication at a UE, comprising at least one means for performing the method of any one of aspects 1 to 19.

[0211] Aspect 22: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 1 to 19.

[0212] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used throughout much of the description, the techniques described herein may also be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0213] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0214] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0215] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or code. Other examples and implementations fall within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0216] Computer-readable media include both non-transient computer storage media and communication media, including any media that facilitates the transfer of a computer program from one place to another. Non-transient storage media can be any available medium that can be accessed by a general or special-purpose computer. As an example and not limitation, non-transient computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, magnetic disk storage or other magnetic storage device, or any other non-transient medium that can be used to carry or store the desired program code means in the form of instructions or data structures and can be accessed by a general or special-purpose computer, or a general or special-purpose processor. Similarly, any connection is also properly referred to as a computer-readable medium. For example, if software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of computer-readable media. Disk and disc, as used herein, include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0217] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items followed by a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Likewise, as used herein, the phrase "based on" should not be read as referencing a closed set of conditions. For example, an example step described as "based on condition A" could be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be read in the same manner as the phrase "based at least in part on."

[0218] In the accompanying drawings, similar components or features may have the same reference number. In addition, components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between the similar components. If only the first reference number is used in the specification, the description applies to any of the similar components having the same first reference number, regardless of the second reference number or other subsequent reference numbers.

[0219] The description set forth herein in conjunction with the accompanying drawings describes example configurations and does not represent all examples that can be implemented or fall within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0220] The description herein is provided to enable one of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: receiving control signaling configuring the UE with a retransmission request time duration for requesting retransmission of a packet relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received and a retransmission request inhibit time duration for inhibiting transmission of a next retransmission request relative to a time when a previous retransmission request was transmitted when the UE is operating according to a first feedback mode; monitoring one or more transmissions comprising at least a subset of packets in the sequence of packets; as well as Before expiration of the retransmission request time duration and before expiration of the retransmission request prohibit time duration, at least in part based on a first retransmission trigger being satisfied and the UE operating according to a second feedback mode, transmitting a first retransmission request to request retransmission of at least one packet in the sequence of packets.

2. The method of claim 1 , wherein transmitting the first retransmission request comprises: The first retransmission request is transmitted based at least in part on the first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of the retransmission request time duration, or a first remaining amount or a first remaining percentage of the retransmission request time duration.

3. The method of claim 1, further comprising: Prior to expiration of the retransmission request time duration and after the first retransmission request, a second retransmission request is transmitted based at least in part on a second retransmission trigger being satisfied.

4. The method of claim 3 , wherein transmitting the second retransmission request comprises: The second retransmission request is transmitted at least in part based on the second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, wherein the second remaining amount or the second remaining percentage is less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger.

5. The method of claim 1, further comprising: A first connection is established with a first base station via a first radio access technology and a second connection is established with a second base station via a second radio access technology, wherein a first transmission of the one or more transmissions is received from the first base station and a second transmission of the one or more transmissions is received from the second base station.

6. The method of claim 5, further comprising: The first retransmission request is transmitted to the first base station based at least in part on the first transmission including the at least one packet.

7. The method of claim 5, further comprising: The first retransmission request is transmitted to the second base station based at least in part on the second transmission including the at least one packet.

8. The method of claim 5, further comprising: transmitting the first retransmission request to the first base station based at least in part on the first transmission including the at least one packet; as well as A second retransmission request is transmitted to the second base station based at least in part on the second transmission from the second base station including a second packet of the at least one packet.

9. The method of claim 1 , wherein receiving the control signaling to configure the UE to have the retransmission request time duration comprises: receiving, from a first base station, first control signaling for configuring the UE to have a first retransmission request time duration; as well as Second control signaling is received from a second base station to configure the UE to have a second retransmission request time duration different from the first retransmission request time duration.

10. The method of claim 1 , wherein transmitting the first retransmission request comprises: The first retransmission request is transmitted based at least in part on the first retransmission trigger, the first retransmission trigger being an amount of remaining available memory in a buffer satisfying a first memory threshold.

11. The method of claim 1 , further comprising: Switching from the first feedback mode to the second feedback mode is based at least in part on the first retransmission trigger, wherein the first retransmission trigger is that the remaining time of the retransmission request time duration meets a first remaining time threshold, or the remaining available memory amount of the buffer meets a first memory threshold.

12. The method of claim 11, further comprising: Switching back to the first feedback mode is based at least in part on the amount of remaining available memory in the buffer not satisfying the first memory threshold.

13. The method of claim 11, wherein the second feedback mode configures the UE to transmit retransmission requests at a higher rate than in the first feedback mode.

14. The method of claim 11, further comprising: Before expiration of the retransmission request time duration and after the first retransmission request, a second retransmission request is transmitted based at least in part on a second retransmission trigger being satisfied, wherein the second retransmission trigger is triggered based at least in part on an amount of remaining available memory in a buffer satisfying a second memory threshold, the second memory threshold being less than a first memory threshold associated with the first retransmission trigger.

15. The method of claim 14, further comprising: Switching from the third feedback mode back to the second feedback mode is based at least in part on the amount of remaining available memory in the buffer not satisfying the second memory threshold.

16. The method of claim 1, wherein the first retransmission request comprises a status protocol data unit indicating the at least one packet.

17. The method of claim 1, wherein the first retransmission request indicates a radio link control sequence number of a packet of the at least one packet.

18. The method of claim 1, wherein the retransmission request time duration is shorter than the retransmission request prohibit time duration.

19. A device for wireless communication, comprising: processor; a memory coupled to the processor; as well as instructions stored in the memory, the instructions being executable by the processor to cause the device to: receiving control signaling that configures the device to have a retransmission request time duration for requesting retransmission of a packet relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received and a retransmission request inhibit time duration for inhibiting transmission of a next retransmission request relative to a time when a prior retransmission request was transmitted when the device is operating according to a first feedback mode; monitoring one or more transmissions comprising at least a subset of packets in the sequence of packets; as well as Before expiration of the retransmission request time duration and before expiration of the retransmission request prohibit time duration, at least in part based on a first retransmission trigger being satisfied and the device operating according to a second feedback mode, transmitting a first retransmission request to request retransmission of at least one packet in the packet sequence.

20. The apparatus of claim 19, further comprising a transmitter, wherein the instructions for transmitting the first retransmission request are executable by the processor to cause the apparatus to: The first retransmission request is transmitted via the transmitter based at least in part on the first retransmission trigger corresponding to a first elapsed amount or a first elapsed percentage of the retransmission request time duration, or a first remaining amount or a first remaining percentage of the retransmission request time duration.

21. The apparatus of claim 19, wherein the instructions are further executable by the processor to cause the apparatus to: Prior to expiration of the retransmission request time duration and after the first retransmission request, a second retransmission request is transmitted based at least in part on a second retransmission trigger being satisfied.

22. The apparatus of claim 21 , wherein the instructions for transmitting the second retransmission request are executable by the processor to cause the apparatus to: The second retransmission request is transmitted at least in part based on the second retransmission trigger corresponding to a second elapsed amount or a second elapsed percentage of the retransmission request time duration, or a second remaining amount or a second remaining percentage of the retransmission request time duration, wherein the second remaining amount or the second remaining percentage is less than the first remaining amount or the first remaining percentage corresponding to the first retransmission trigger.

23. The apparatus of claim 19, wherein the instructions are further executable by the processor to cause the apparatus to: A first connection is established with a first base station via a first radio access technology and a second connection is established with a second base station via a second radio access technology, wherein a first transmission of the one or more transmissions is received from the first base station and a second transmission of the one or more transmissions is received from the second base station.

24. The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to: The first retransmission request is transmitted to the first base station based at least in part on the first transmission including the at least one packet.

25. The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to: The first retransmission request is transmitted to the second base station based at least in part on the second transmission including the at least one packet.

26. The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to: transmitting the first retransmission request to the first base station based at least in part on the first transmission including the at least one packet; and A second retransmission request is transmitted to the second base station based at least in part on the second transmission from the second base station including a second packet of the at least one packet.

27. A device for wireless communication, comprising: means for receiving control signaling configuring the apparatus to have a retransmission request time duration for requesting retransmission of a packet relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received and a retransmission request inhibit time duration for inhibiting transmission of a next retransmission request relative to a time when a prior retransmission request was transmitted when the apparatus is operating according to a first feedback mode; means for monitoring one or more transmissions comprising at least a subset of packets in said sequence of packets; as well as Means for transmitting a first retransmission request to request retransmission of at least one packet in the sequence of packets, based at least in part on a first retransmission trigger being satisfied and the device operating according to a second feedback mode, before expiration of the retransmission request time duration and before expiration of the retransmission request inhibit time duration.

28. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to: receiving control signaling configuring the UE with a retransmission request time duration for requesting retransmission of a packet relative to a time when a packet in a sequence of packets was determined to be unsuccessfully received and a retransmission request inhibit time duration for inhibiting transmission of a next retransmission request relative to a time when a previous retransmission request was transmitted when the UE is operating according to a first feedback mode; monitoring one or more transmissions comprising at least a subset of packets in the sequence of packets; as well as Before expiration of the retransmission request time duration and before expiration of the retransmission request prohibit time duration, at least in part based on a first retransmission trigger being satisfied and the UE operating according to a second feedback mode, transmitting a first retransmission request to request retransmission of at least one packet in the sequence of packets.

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