WO2019218340A1

WO2019218340A1 - Resource allocation for ultra-reliable low latency communications package

Info

Publication number: WO2019218340A1
Application number: PCT/CN2018/087476
Authority: WO
Inventors: Changlong Xu; Liangming WU; Wanshi Chen; Hao Xu
Original assignee: Qualcomm Incorporated
Priority date: 2018-05-18
Filing date: 2018-05-18
Publication date: 2019-11-21

Abstract

Methods, systems, and devices for wireless communications are described. A base station may determine a first code rate for an initial transmission and a second code rate for a retransmission based at least in part on a target channel condition, an information block length, a target block error code rate for the retransmission, or a combination thereof. A user equipment (UE) may transmit an initial transmission using a first number of RBs (corresponding to a first code rate), and may transmit the retransmission using a second number of RBs (corresponding to the second code rate). The UE may determine the second number of RBs based at least in part on an indication to use a different number of RBs for the retransmission, which may include a ratio between the first and second number of RBs, a transport block size table, a mode indicator, or a configuration for the retransmission.

Description

RESOURCE ALLOCATION FOR ULTRA-RELIABLE LOW LATENCY COMMUNICATIONS PACKAGE

BACKGROUND

The following relates generally to wireless communications, and more specifically to resource allocation optimization for an ultra-reliable low latency communications package.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the 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, LTE-Advanced (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 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-OFDM (DFT-S-OFDM) . A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

In some wireless communications systems, a UE may transmit uplink communications to a base station over an uplink communication channel. In some cases, the base station may not properly receive and decode the uplink communication channel (e.g., due to interference in the wireless communications channel) . The base station may transmit a negative acknowledgement (NACK) for the initial transmission. The UE may receive the NACK and may send a retransmission to the base station. In some examples, the UE may continue sending retransmissions until the information is properly received.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support resource allocation optimization for an ultra-reliable low latency communications package. Generally, the described techniques provide for determining different code rates, and using different numbers of resource blocks (RBs) , for an initial transmission and any retransmission. A base station may determine a first code rate for an initial transmission and a second code rate for a retransmission based at least in part on a target channel condition, an information block length, a target block error code rate for the retransmission, or a combination thereof. A user equipment (UE) may transmit an initial transmission using a first number of RBs (corresponding to a first code rate) , and may transmit the retransmission using a second number of RBs (corresponding to the second code rate) . The UE may determine the second number of RBs based at least in part on an indication to use a different number of RBs for the retransmission, which may include a ratio between the first and second number of RBs, a transport block size table, a mode indicator, a configuration for the retransmission, or a combination thereof.

A method of wireless communication at a UE is described. The method may include transmitting, by the UE, a first uplink communication using a first number of RBs, receiving, from a base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission, and transmitting the second uplink communication based at least in part on the indication.

An apparatus for wireless communication at a UE is described. The apparatus may include means for transmitting, by the UE, a first uplink communication using a first number of RBs, means for receiving, from a base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and means for transmitting the second uplink communication based at least in part on the indication.

Another apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to transmit, by the UE, a first uplink communication using a first number of RBs, receive, from a base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and transmit the second uplink communication based at least in part on the indication.

A non-transitory computer readable medium for wireless communication at a UE is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to transmit, by the UE, a first uplink communication using a first number of RBs, receive, from a base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and transmit the second uplink communication based at least in part on the indication.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs may include receiving the indication in downlink control information (DCI) associated with the first uplink communication. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs may include receiving a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs. Receiving the resource ratio may further include receiving a number of bits, wherein different bit combinations correspond to different predefined resource ratios.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs may include receiving a transport block size (TBS) adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the scalar value corresponds to a modulation and coding scheme identified in the TBS table. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs may include receiving a mode indicator in DCI, wherein the mode indicator indicates a mode for determining the different number of RBs. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the mode indicator is associated with a quantized resource ratio that is based at least in part on a signal-to-noise ratio (SNR) .

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs may include receiving a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the first configuration includes one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions, and the second configuration includes one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs further includes receiving the first configuration indication and the second configuration indication via a semi-persistent scheduling communication.

A method of wireless communication at a base station is described. The method may include receiving, by the base station and from a UE, a first uplink communication using a first number of RBs, transmitting an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and receiving the second uplink communication based at least in part on the indication.

An apparatus for wireless communication at a base station is described. The apparatus may include means for receiving, by the base station and from a UE, a first uplink communication using a first number of RBs, means for transmitting an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and means for receiving the second uplink communication based at least in part on the indication.

Another apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to receive, by the base station and from a UE, a first uplink communication using a first number of RBs, transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and receive the second uplink communication based at least in part on the indication.

A non-transitory computer readable medium for wireless communication at a base station is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to receive, by the base station and from a UE, a first uplink communication using a first number of RBs, transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and receive the second uplink communication based at least in part on the indication.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the indication to use the different number of RBs may include transmitting the indication in DCI associated with the first uplink communication. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the indication to use the different number of RBs may include transmitting a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the resource ratio may include transmitting a number of bits, wherein different bit combinations correspond to different predefined resource ratios.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the indication to use the different number of RBs may include transmitting a TBS adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the scalar value corresponds to a modulation and coding scheme identified in the TBS table. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the indication to use the different number of RBs may include transmitting a mode indicator in DCI, wherein the mode indicator indicates a mode for determining the different number of RBs. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the mode indicator is associated with a quantized resource ratio that is based at least in part on a SNR.

In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the indication to use the different number of RBs may include transmitting a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the first configuration includes one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions, and the second configuration includes one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the indication to use the different number of RBs further includes transmitting the first configuration indication and the second configuration indication via a semi-persistent scheduling communication.

Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining the indication of the different number of RBs based at least in part on a channel condition. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, determining the indication of the different number of RBs may include simulating a BLER curve for a plurality of code rates, selecting, based at least in part on a target channel condition, a second code rate for the second uplink communication based at least in part on the plurality of BLER curves, and selecting a first code rate for the first uplink communication based at least in part on the selected second code rate. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for selecting the ratio of the different number of RBs and the first number of RBs based at least in part on the second code rate and the first code rate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communications that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a communications flow in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a communications flow in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a transport block size table in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a communications flow in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 7 illustrates an example of a communications flow in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 8 illustrates an example of a communications flow in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIGs. 9 and 10 show block diagrams of devices that support resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 11 shows a block diagram of a communications manager that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 12 shows a diagram of a system including a device that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIGs. 13 and 14 show block diagrams of devices that support resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 15 shows a block diagram of a communications manager that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIG. 16 shows a diagram of a system including a device that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

FIGs. 17 through 19 show flowcharts illustrating methods that support resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Some wireless communications system may use ultra-reliable low latency communications (URLLC) techniques. Such URLLC techniques may impose certain latency and error rate requirements. For example, URLLC techniques may require a block error rate (BLER) of 10 ^-5 and a latency of no more than 0.5 ms. Such a latency requirement may allow no more than two transmissions for a communication: an initial transmission and a retransmission.

In some examples, the target BLER for each transmission may be selected such that the same code rate (and the same number of resource blocks (RBs) ) may be used for the initial transmission and all retransmissions. However, with a limited number of available retransmissions, use of such techniques may not provide adequate BLER and/or meet applicable BLER requirements. For example, with a target BLER of 10 ^-5, the target BLER for each of two possible transmissions may be 10 ^-5/2. However, a target BLER of 10 ^-5 may not be optimal for the initial transmission. For example, using such an equal resource BLER may result in worse signal-to-noise ratio (SNR) and poorer spectrum efficiency than could be obtained in accordance with other resource allocations.

Alternatively, a base station may determine different code rates for a limited number of available transmissions based at least in part on a target channel condition, an information block length, a target block error code rate for the retransmission, or a combination thereof. For example, the base station may determine a first code rate for an initial transmission and a second code rate for a retransmission. The base station may simulate BLER curves at different code rates and select a second code rate based at least in part on the BLER curves, a target channel condition (e.g., a target SNR) , and a target BLER for the retransmission. The base station may select a first code rate based at least in part on the second code rate. The base station may also determine a quantized ratio between a first number of RBs to be used for the initial transmission and a second number of RBs to be used for the retransmission based at least in part of the first code rate and the second code rate.

The base station may transmit an indication of the first code rate and/or the first number of RBs to a user equipment (UE) . The UE may transmit an initial uplink communication using the first number of RBs. In some examples, the base station may not properly receive and decode the initial uplink communication (e.g., due to interference in the wireless communications system) , and may transmit a negative acknowledgement (NACK) corresponding to the initial communication. The UE may then transmit a retransmission to the base station using the second number of RBs.

The UE may determine the second number of RBs based at least in part on an indication from the base station to use a different number of RBs for the retransmission. In some examples, the indication to use a different number of RBs may include an indication of the ratio between the first number of RBs and the second number of RBs. In some examples, the indication to use a different number of RBs may include an indication of a specific transport block size (TBS) table to be used, or an indication that a scalar factor, identified in a TBS table, is to be applied. In some examples, the indication to use a different number of RBs may include a mode indicator that indicates how the UE should determine the second number of RBs. In some examples, the indication to use a different number of RBs may include a configuration for the retransmission. The indication to use a different number of RBs may be transmitted in downlink control information (DCI) , semi-persistent scheduling information, or the like.

By using such techniques, the wireless system may have improved performance (e.g., SNR and/or spectrum efficiency) while ensuring that the BLER requirements are met within the allotted number of transmissions.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to resource allocation optimization for an ultra-reliable low latency communications package.

Ffd. 1 illustrates an example of a wireless communications system 100 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation Node B or giga-nodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up only a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also 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 the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be 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, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications 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 cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

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) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet(s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that can tolerate interference from other users.

Wireless communications system 100 may also operate in an 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, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving devices are equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. 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. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

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

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105. Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

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

In some cases, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may 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 cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may in some cases perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical (PHY) layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a 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 throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an E-UTRA absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as OFDM or DFT-s-OFDM) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR, etc.) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a 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) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that can support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A UE 115 may be configured with multiple downlink CCs and one or more uplink CCs according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In some cases, an eCC may utilize a different symbol duration than other CCs, which may include use of a reduced symbol duration as compared with symbol durations of the other CCs. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

One or more of the base stations 105 may include a base station communications manager 101, which may determine code rates for an initial transmission and any retransmission. The code rates for an initial transmission and a retransmission may differ. In some examples, due to latency requirements, only a single retransmission may be scheduled.

In some examples, the base station communications manager 101 may determine a first code rate for an initial transmission and a second code rate for a retransmission based at least in part on a target channel condition (e.g., a target SNR) , a target block error rate, an information block length, or a combination thereof.

For example, the base station communications manager 101 may simulate a BLER curve for different code rates. In some examples, the base station communications manager 101 may simulate a plurality of BLER curves for a single information block length K. In some other examples, the base station communications manager 101 may simulate a plurality of BLER curves for each information block length K. The base station communications manager 101 may select a target channel condition (e.g., a target SNR of 5 dB) .

The base station communications manager 101 may select a second code rate based at least in part on the plurality of BLER curves and the target channel condition. In some examples, the base station communications manager 101 may select a single second code rate for a single information block length K. In some other examples, the base station communications manager 101 may select a plurality of second code rates for a plurality of information block lengths K.

The base station communications manager 101 may select a first code rate based at least in part on the selected second code rate. In some examples, the base station communications manager 101 may select a single first code rate for a single information block length K. In some other examples, the base station communications manager 101 may select a plurality of first code rates for a plurality of information block lengths K.

The base station communications manager 101 may determine a ratio between a first number of RBs to be used for the initial transmission and a second number of RBs to be used for the retransmission based at least in part on the first code rate and the second code rate. The ratio may be quantized. In some examples, the second number of RBs may be greater than the first number of RBs.

The base station communications manager 101 may transmit an indication to use a second number of RBs for a retransmission to a UE 115 based at least in part on the first code rate, the second code rate, the ratio, or a combination thereof. The base station communications manager 101 may transmit the indication in DCI, semi-persistent scheduling information, or other control transmissions.

In some examples, the base station communications manager 101 may transmit an indication of the ratio between the first number of RBs and the second number of RBs (e.g., in DCI) to a UE 115.

In some examples, the base station communications manager 101 may generate and transmit a TBS table to a UE 115, or otherwise indicate to the UE 115 a TBS table to be used. The TBS table may include one or more transport block sizes for the initial transmission (e.g., based at least in part on a modulation and coding scheme and/or a number of physical resource blocks) . The TBS table may also include a scalar vector corresponding to the ratio between the first number of RBs and the second number of RBs.

In some examples, the base station communications manager 101 may transmit a mode indicator to a UE 115. The mode indicator may indicate how the UE 115 should select the number of RBs to be used in the retransmission. The mode indicator may be transmitted in DCI.

In some examples, the base station communications manager 101 may transmit a configuration for the retransmission to the UE 115. The configuration for the retransmission may be transmitted with a configuration for the initial transmission, e.g., in semi-persistent scheduling information. The configuration for the retransmission may indicate a modulation and coding scheme and/or a resource allocation (e.g., a ratio or a number of RBs) , which may differ from the modulation and coding scheme and/or resource allocation indicated in the configuration for the initial transmission.

UEs 115 may include a UE communications manager 102, which may be configured to determine the number of RBs to be used for retransmissions. The number of RBs to be used for retransmissions may differ from the number of RBs to be used for initial transmissions.

In some examples, the UE communications manager 102 may transmit an initial transmission. The initial transmission may include a first number of RBs corresponding to the first code rate determined by a base station 105. The UE communications manager 102 may determine the first number of RBs based at least in part on an indication of the first code rate of the first number of RBs received from a base station 105.

In some examples, the UE communications manager 102 may receive a NACK corresponding to the initial transmission, and may send a retransmission based at least in part on receiving the NACK. The UE communications manager 102 may determine a second number of RBs to be used for the retransmission based at least in part on an indication to use a different number of RBs for the retransmission.

In some examples, the UE communications manager 102 may receive an indication of the ratio between the first number of RBs and the second number of RBs (e.g., in DCI) from a base station 105. The UE communications manager 102 may determine the second number of RBs by applying the ratio to the first number of RBs.

In some examples, the UE communications manager 102 may receive a TBS table from a base station 105. The TBS table may include one or more transport block sizes for the initial transmission (e.g., based at least in part on a modulation and coding scheme and/or a number of physical resource blocks) . The TBS table may also include a scalar vector corresponding to the ratio between the first number of RBs and the second number of RBs. The UE communications manager 102 may determine the first number of RBs based at least in part on the one or more transport block sizes for the initial transmission, and may determine the second number of RBs based at least in part on applying the scalar vector to the one or more transport block sizes for the initial transmission.

In some examples, the UE communications manager 102 may receive a mode indicator from a base station 105. The mode indicator may indicate how the UE communications manager 102 should select the number of RBs to be used in the retransmission. For example, the UE communications manager 102 may determine that the second number of RBs is the same as the first number of RBs when a first mode is indicated by the mode indicator, and may determine the second number of RBs based at least in part on a ratio between the first and second number of RBs, a TBS table, and/or a configuration for the retransmission when a second mode is indicated. In some other examples, the UE communications manager 102 may determine that the second number of RBs is the same as the first number of RBs when a first mode is indicated by the mode indicator, may determine the second number of RBs based at least in part on a ratio between the first and second number of RBs when a second mode is indicated, may determine the second number of RBs based at least in part on a TBS table when a third mode is indicated, and may determine the second number of RBs based at least in part on a configuration for the retransmission when a fourth mode is indicated.

In some examples, the UE communications manager 102 may receive a configuration for the retransmission from a base station 105. The configuration for the retransmission may be transmitted with a configuration for the initial transmission, e.g., in semi-persistent scheduling information. The configuration for the retransmission may indicate a modulation and coding scheme and/or a resource allocation (e.g., a ratio or a number of RBs) , which may differ from the modulation and coding scheme and/or resource allocation indicated in the configuration for the initial transmission. The UE communications manager 102 may determine the second number of RBs based at least in part on the configuration for the retransmission.

FfG. 2 illustrates an example of a wireless communications system 200 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communication system 100.

The wireless communications system 200 may include a base station 205 and a UE 210. The base station 205 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 210 may be an example of aspects of UE 115 described with reference to FIG. 1. The base station 205 and the UE 210 may communicate via one or more communication channels 215. The base station 205 may transmit downlink communications to the UE 210 over a downlink communication channel, and the UE 210 may transmit uplink communications to the base station 205 over an uplink communication channel.

The base station 205 and the UE 210 may use URLLC protocols to transmit uplink and downlink communications. In URLLC, there may be strict latency requirements for the communications channel 215. For example, the requirements for the communication channel 215 may be a BLER of less than 10 ^-5, and a latency of less than 0.5 ms. Under such constraints, the base station 205 may be able to transmit only two transmissions prior to expiration of the latency period, i.e., an initial transmission and a single retransmission.

In some examples, the target BLER for the first transmission and each retransmission may be fixed, e.g., at 10%. However, because only two transmissions are permitted, such a fixed BLER may not satisfy the BLER requirement of 10 ^-5.

The base station 205 and/or the UE 210 may use a resource allocation optimization technique to select code rates (and corresponding resource allocations) for the initial transmission and the retransmission. For example, the base station 205 may use such techniques to ensure a 10 ^-5 target BLER for the retransmission.

The base station 205 may determine the code rates for the initial transmission and retransmission based at least in part on a channel condition (e.g., a target SNR) , an information block length for the initial transmission and retransmission, or a combination thereof.

In some examples, the base station 205 may simulate BLER curves at different code rates. The BLER curves may be simulated based on an information block length K, and may show BLER versus SNR. The base station 205 may accordingly generate a plurality of BLER curves corresponding to a plurality of code rates. In some examples, the base station 205 may determine a target channel condition. In some examples, the target channel condition may be a target SNR. For example, the target SNR may be 5 dB.

The base station 205 may select a code rate for a retransmission (the second code rate) . In some examples, the base station 205 may select the second code rate based at least in part on the plurality of BLER curves, the target channel condition, a target BLER, or a combination thereof. For example, the base station 205 may identify a BLER curve that meets the target channel condition at the target BLER. The base station 205 may select the code rate corresponding to the identified BLER curve as the second code rate.

The base station 205 may select a code rate for an initial transmission (the first code rate) based at least in part on the selected second code rate. In some examples, the first code rate may be selected to maximize the throughput under the constraint of the selected second code rate.

The base station 205 may determine a ratio of resource allocation between the retransmission and the initial transmission. The base station 205 may select the ratio by quantizing the ratio of resource allocation based at least in part on the first code rate and the second code rate.

In some examples, the base station 205 may determine a single value for the first and second code rates. In some other examples, the base station 205 may determine multiple values for the first and second code rates based at least in part on different modulation and coding scheme and/or physical resource block sizes.

For uplink transmissions, the base station 205 may transmit information about the first code rate to the UE 210. For example, the base station 205 may transmit an indication of the first code rate to the UE 210 in DCI or in semi-persistent scheduling information. In some examples, the base station 205 may transmit the indication of the first code rate to the UE 210 in a TBS table or as part of configuration information for the initial transmission. The UE 205 may transmit an initial transmission based at least in part on the indication of the first code rate (corresponding to a first number of RBs.

In some examples, the base station 205 may not properly receive and decode the initial transmission (e.g., due to interference in the wireless communications system 200) . In such examples, the base station 205 may transmit a NACK to the UE 210. The UE 210 may transmit a retransmission based at least in part on receiving the NACK.

The UE 210 may send the retransmission using a different number of RBs than the first number of RBs. The UE 210 may determine the number of RBs to be used for the retransmission based at least in part on an indication to use a second number of RBs transmitted by the base station 205.

In some examples, the indication to use a second number of RBs may include an indication of the ratio between the first number of RBs and the second number of RBs. Such an indication may be included in the DCI that also included the information about the first code rate. The UE 210 may determine the second number of RBs by applying the ratio to the first number of RBs. The ratio may be quantized. In some examples, the second number of RBs may be greater than the first number of RBs. For example, the ratio may be one of 4∶1, 3∶1, 2∶1, or 1∶1.

In some examples, the indication to use a second number of RBs may include a scalar vector. The scalar vector may be included in a TBS table. The UE 210 may determine the second number of RBs by applying the scalar vector to the transport block size for the initial transmission. The ratio may be quantized. In some examples, the second number of RBs may be greater than the first number of RBs. For example, the scalar vector may be between 0.25 and 1.

In some examples, the indication to use a second number of RBs may include a mode indication, which may be included in DCI. The indication may indicate whether the UE 210 should use a first resource allocation mode or a second resource allocation mode to select the second number of RBs. In the first resource allocation mode, the UE 210 may use the first number of RBs as the second number of RBs. In the second resource allocation mode, the UE 210 may determine the second number of RBs in some other manner, e.g., based at least in part on a ratio between the first number of RBs and the second number of RBs, a scalar vector in a TBS table, or a configuration for the retransmission.

In some examples, the indication to use a second number of RBs may include a configuration for the retransmission. The configuration for the retransmission may indicate a modulation and coding scheme to be used for the retransmission and/or a resource allocation indication (e.g., a ratio or a number of RBs) to be used for the retransmission. In some examples, the configuration for the retransmission may be sent with the configuration for the initial transmission in semi-persistent scheduling information. In some examples, the configurations for the transmission and the retransmission may be a TBS table as described with reference to FIG. 5, or a first TBS table corresponding to the initial transmission and a second TBS table corresponding to the retransmission (although the scalar vector described with reference to FIG. 5 may be omitted in the latter case in favor of the second TBS table) .

In some examples, latency requirements may allow two or more retransmissions. In such examples, the base station 205 may determine code rates for each retransmission, and may transmit an indication to use different numbers of RBs for each retransmission. The same number of RBs may be indicated for each retransmission, or different numbers of RBs may be calculated and used for each retransmission.

FfG. 3 illustrates an example of a communications flow 300 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The communications flow 300 shows communications between a base station 305 and a UE 310. The base station 305 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 310 may be an example of aspects of UE 115 described with reference to FIG. 1.

The base station 305 may determine a resource ratio for a retransmission at 315. The resource ratio may be determined based at least in part on resource allocation algorithm as described with reference to FIG. 8. In some examples, the resource ratio may be determined based at least in part on a target channel condition, a selected code rate for the retransmission, a selected code rate for the initial transmission, or a combination thereof. In some examples (e.g., when latency requirements allow the UE 310 to attempt only two transmissions before timing out) , the resource ratio may be a single value that describes the ratio of resource allocation between an initial transmission and a retransmission. In some other examples (e.g., when latency requirements allow the UE 310 to attempt three or more transmissions before timing out) , the resource ratio may be a single value that applies to all retransmissions, or may include multiple values describing ratios of resource allocations for each retransmission (with reference to the initial transmission or the previous transmission) . In some examples, the resource ratio may be quantized as described with reference to FIG. 11.

The base station 305 may transmit DCI 320 for an initial transmission to the UE 310. The DCI 320 may be transmitted over a PDCCH. The DCI 320 for the initial transmission may include an indication of the resource ratio determined at 315. In some examples, the indication of the resource ratio may be a number of bits, with each combination of bits corresponding to a resource ratio. For example, in a simple scenario in which the resource ratio may be either 1∶1, 2∶1, 3∶1, or 4∶1, the indication of the resource ratio may be a two bit string whose mapping is described in Table 1. Other mappings may be used, and larger bits strings may be used when a greater number of possible resource ratios exist.

Two Bit String	Resource Ratio
00	1∶1
01	2∶1
10	3∶1
11	4∶1

Table 1

The UE 310 may send an initial transmission 325 to the base station 305. The resource number of resource blocks for the initial transmission 325 may be determined based at least in part on a first code rate. The number of resource blocks for the initial transmission 325 and/or the first code rate may be included in the DCI 320 for the initial transmission.

The base station 305 may transmit a NACK 330 to the UE 310. The base station 305 may transmit the NACK 330 based at least in part on determining that at least some portion of the initial transmission 325 was not properly received (e.g., due to interference or the like) .

The UE 310 may determine a number of resource blocks for the retransmission at 335. The UE 310 may determine to transmit a retransmission of the initial transmission 325 based at least in part on receipt of the NACK 330, and may determine the number of resource blocks for the retransmission based at least in part on the resource ratio included in the DCI 320. The UE 310 may determine the number of resource blocks for the retransmission by applying the resource ratio to the number of resource blocks used in the initial transmission 325. The number of resource blocks for the retransmission may be determined without receiving further DCI over a PDCCH.

The UE 310 may send a retransmission 340 to the base station 305. The retransmission 340 may include the same information transmitted in the initial transmission 325, but may use a different number of resource blocks (e.g., when the resource ratio is a ratio other than 1∶1) .

FfG. 4 illustrates an example of a communications flow 400 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The communications flow 400 shows communications between a base station 405 and a UE 410. The base station 405 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 410 may be an example of aspects of UE 115 described with reference to FIG. 1.

The base station 405 may identify a TBS table at 415. In some examples, the base station 405 may store one or more TBS tables. In some other examples, the base station 405 may generate a TBS table based at least in part on a resource allocation algorithm as described with reference to FIG. 8. In some examples, the TBS table may be generated based at least in part on a target channel condition, a selected code rate for a retransmission, a selected code rate for an initial transmission, a modulation and coding scheme, or a combination thereof.

The TBS table may be a TBS table 500 as described with reference to FIG. 5. The TBS table may identify one or more candidate numbers of transport block sizes for an initial transmission. For example, the TBS table may identify a candidate number of transport block size for each combination of modulation and coding scheme and number of physical resource blocks. The TBS table may also include an indication of a resource ratio, which may be a scalar vector. In some examples (e.g., when latency requirements allow the UE 410 to attempt only two transmissions before timing out) , the TBS table may be include a single value for each modulation and coding scheme that describes the ratio of resource allocation between an initial transmission and a retransmission. In some other examples (e.g., when latency requirements allow the UE 410 to attempt three or more transmissions before timing out) , the TBS table may include a single value for each modulation and coding scheme that applies to all retransmissions, or may include multiple values for each modulation and coding scheme describing ratios of resource allocations for each retransmission (with reference to the initial transmission or the previous transmission) . At 420, the base station 405 may transmit the TBS table to the UE 410, or at least an indication of the TBS table, so that the UE 410 may also be enabled to identify the TBS table.

The UE 410 may determine the number of resource blocks for the initial transmission based at least in part on the TBS table. In some examples, the UE 410 may select a transport block size from the TBS table based at least in part on a modulation and coding scheme and a number of physical resource blocks to be transmitted, and may determine the number of resource blocks based at least in part on the selected transport block size. The UE 410 may then send the initial transmission 430 to the base station 405. The initial transmission 430 may include the number of resource blocks determined at 425.

The base station 405 may transmit a NACK 435 to the UE 410. The base station 405 may transmit the NACK 435 based at least in part on determining that at least some portion of the initial transmission 430 was not properly received (e.g., due to interference or the like) .

The UE 410 may determine a number of resource blocks for the retransmission at 440. The UE 410 may determine the number of resource blocks for the retransmission based at least in part on the TBS table. For example, the UE 410 may select a scalar vector from the TBS table based at least in part on a modulation and coding scheme. The UE 410 may apply the scalar vector the transport block size used for the initial transmission to calculate the transport block size for the retransmission.

The UE 410 may send a retransmission 445 to the base station 405. The retransmission 445 may include the same information transmitted in the initial transmission 430, but may use a different number of resource blocks (e.g., when the scalar vector is not equal to 1) .

FfG. 5 illustrates an example of a TBS table 500 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The TBS table 500 includes a plurality of transport block sizes S _x, _y, where x refers to a modulation and coding scheme index and y refers to a number of physical resource blocks. A UE (e.g., UE 410 described with reference to FIG. 4) may transmit using one or M modulation and coding schemes, and may transmit up to N physical resource blocks in a single transmission.

The UE may select a transport block size for an initial transmission based at least in part on the modulation and coding scheme and the number of physical resource blocks. For example, the UE may determine a modulation and coding scheme index to be used for transmitting the initial transmission. In some examples, the UE may receive an indication of the modulation and coding scheme from a base station (e.g., base station 405 described with reference to FIG. 4) , and may determine the modulation and coding scheme index based at least in part on the indication of the modulation and coding scheme. In some other examples, the UE may receive the modulation and coding scheme index from the base station.

The UE may select a row of the TBS table 500 based at least in part on the determined modulation and coding scheme index. For example, when the UE determines that the modulation and coding scheme corresponding to index 2 is to be used for the initial transmission, the UE may select the row 505 corresponding to index 2.

The UE may select a column of the TBS table 500 based at least in part on the number of physical resource blocks to be included in the initial transmission. For example, when N physical resource blocks are to be included in the initial transmission, the UE may select the column 510 corresponding to N physical resource blocks.

The UE may select the cell corresponding to row 505 and column 505, and may us the transport block size S _2, _N in that cell to determine the number of resource blocks to be allocated for the initial transmission.

In some examples, the base station may not properly receive the entirety of the initial transmission, and may respond to the initial transmission with a NACK. In such examples, the UE may determine a number of resource blocks to be included in the retransmission based at least in part on the TBS table 500. For example, the UE may select a scalar vector β from the scalar vector column 515. The values of scalar vector β may correspond to the resource ratios described with reference to FIG. 3. For example, when the available resource ratios may range from 1∶1 to 4∶1, the scalar vector β may take values between 1 and 0.25. The scalar vector β may be vary inversely with the modulation and coding scheme index.

The UE may apply the selected scalar vector (e.g., β ₂) to the transport block size selected for the initial transmission (e.g., S _2, _N) to determine the transport block size for the retransmission (e.g., β ₂S _2, _N) . The UE may determine the number of resource blocks to be included in the retransmission based at least in part on the transport block size for the retransmission.

FfG. 6 illustrates an example of a communications flow 600 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The communications flow 600 shows communications between a base station 605 and a UE 610. The base station 605 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 610 may be an example of aspects of UE 115 described with reference to FIG. 1.

The base station 605 may determine a mode indicator at 615. In some examples, the UE 610 may be capable of transmitting in accordance with a first resource allocation mode and a second resource allocation mode. The first resource allocation mode may be, for example, a mode in which the same code rate and resource allocation (e.g., number of resource blocks) are used for an initial transmission and any retransmissions. The second resource allocation mode may be, for example, a mode in which different code rates and/or resource allocations (e.g., number of resource blocks) are used for an initial transmission and any retransmissions. For example, the second resource allocation mode may involve the UE calculating code rates and/or resource allocations based at least in part on a resource ratio as described with reference to FIG. 3, based at least in part on a TBS table as described with reference to FIG. 4, or based at least in part on initial transmission and retransmission configurations as described with reference to FIG. 7.

The base station 605 may transmit, at 620, a mode indicator for the selected mode to the UE 610. The mode indicator may indicate the way in which the UE 610 is to determine the resource allocation (e.g., modulation and coding scheme and resource size) for the initial transmission and/or any retransmissions. In some examples, the mode indicator may be one or more bits. For example, where the UE 610 is capable of operating in either a first resource allocation mode or a second resource allocation mode, the mode indicator may be a single bit where a “0” corresponds to the first resource allocation mode and a “1” corresponds to the second resource allocation mode.

The UE 610 may determine a number of resource blocks for an initial transmission at 625. The UE 610 may determine the number of resource blocks for an initial transmission based at least in part on an indicator resource allocation mode. For example, the UE 610 may determine the resource allocation mode to be used based at least in part on the mode indicator, and may use the determined resource allocation mode to determine the number of resource blocks to be used. In some examples, the UE 610 may determine that multiple resource blocks are to be used for each assigned resource block. For example, the UE 610 may determine that each resource block assigned indicates three resource blocks. In some examples, this interpretation may be separately configured for each UE. For example, another UE may determine that each resource block assigned indicates two resource blocks.

The UE 610 may then send the initial transmission 630 to the base station 605. The initial transmission 630 may include the number of resource blocks determined at 625. The base station 605 may transmit a NACK 635 to the UE 610. The base station 605 may transmit the NACK 635 based at least in part on determining that at least some portion of the initial transmission 630 was not properly received (e.g., due to interference or the like) .

The UE 610 may determine a number of resource blocks for the retransmission at 640. The UE 610 may determine the number of resource blocks for the retransmission based at least in part on the mode indicator that was previously transmitted to the UE 610 (at 620) . Alternatively, an updated mode indicator may be transmitted to the UE 610, and the UE 610 may determine the number of resource blocks for the retransmission based at least in part on the updated mode indicator. For example, the UE 610 may determine the resource allocation mode to be used based at least in part on the mode indicator, and may use the determined resource allocation mode to determine the number of resource blocks to be used. In some examples, the selected resource allocation mode may involve applying a resource ratio or scalar vector to the number of resource blocks included in the initial transmission 630.

The UE 610 may send a retransmission 645 to the base station 605. The retransmission 645 may include the same information transmitted in the initial transmission 630, but may use a different number of resource blocks (e.g., when the second resourFe allocation mode is indicated by the mode indicator) .

FfG. 7 illustrates an example of a communications flow 700 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The communications flow 700 shows communications between a base station 705 and a UE 710. The base station 705 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 710 may be an example of aspects of UE 115 described with reference to FIG. 1.

The base station 705 may identify configurations for an initial transmission and one or more retransmissions at 715. In some examples, the base station 705 may store one or more candidate configurations. In some other examples, the base station 705 may generate a the configurations based at least in part on a resource allocation algorithm described with reference to FIG. 8. In some examples, the configurations may be generated based at least in part on a target channel condition, a selected code rate for a transmission, a selected code rate for an initial transmission, a modulation and coding scheme, or a combination thereof.

The configurations may indicate, for each transmission, a modulation and coding scheme and/or a resource allocation. For example, the configurations may include a first configuration for the initial transmission. The first configuration may indicate a modulation and coding scheme and a resource allocation for the initial transmission. In some examples, the initial configuration may include a single value for each of the modulation and coding scheme and the resource allocation. The configurations may also include a second configuration for a retransmission. The second configuration may indicate a modulation and coding scheme and a resource allocation for the retransmission. In some examples, the second configuration may be indicated based at least in part on a resource ratio, scalar vector, or the like, which provides a value relative to the values included in the first configuration. The second configuration may differ from the first configuration, e.g., by providing a larger resource allocation for the retransmission.

The base station 705 may transmit semi-persistent scheduling information 720 to the UE 710. The semi-persistent scheduling information 720 may include indications of the configurations for the initial transmission and the retransmission, which may be the configurations or any indication thereof, e.g., a bit or string of bits corresponding to candidate configurations.

The UE 710 may determine the number of resource blocks for the initial transmission based at least in part on the configuration for initial transmissions. The UE 710 may send the initial transmission 730 to the base station 705. The initial transmission 730 may include the number of resource blocks determined at 725.

The base station 705 may transmit a NACK 735 to the UE 710. The base station 705 may transmit the NACK 735 based at least in part on determining that at least some portion of the initial transmission 730 was not properly received (e.g., due to interference or the like) .

The UE 710 may determine a number of resource blocks for the retransmission at 740. The UE 710 may determine the number of resource blocks for the retransmission based at least in part on the configuration for the retransmission. The UE 710 may send a retransmission 745 to the base station 705. The retransmission 745 may include the same information transmitted in the initial transmission 730, but may use a different number of resource blocks (e.g., when the resource allocation in the configuration for the initial transmission is not the same as the resource allocation in the configuration for the retransmission) .

FfG. 8 illustrates an example of a communications flow 800 in a wireless communications system that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communication system 100.

The communications flow 800 may show communications between a base station 805 and a UE 810. The base station 805 may be an example of aspects of base station 105 described with reference to FIG. 1. The UE 810 may be an example of aspects of UE 115 described with reference to FIG. 1.

The base station 805 may simulate BLER curves at different code rates at 815. The BLER curves may be simulated based on an information block length K, and may be show BLER versus SNR. The base station 805 may accordingly generate a plurality of BLER curves corresponding to a plurality of code rates.

The base station 805 may determine a target channel condition at 820. In some examples, the target channel condition may be a target SNR. For example, the target SNR may be 5 dB.

The base station 805 may select a code rate for a retransmission (the second code rate) at 825. The base station 805 may select the second code rate based at least in part on the plurality of BLER curves, the target channel condition, a target BLER, or a combination thereof. For example, the base station 805 may identify a BLER curve that meets the target channel condition at the target BLER. The base station 805 may select the code rate corresponding to the identified BLER curve as the second code rate. This may be expressed as shown in Equation (1):

r _2nd=argmax _r BLER _r, _s＜BLER_target (1)

where r _2nd is the second code rate, r is the code rate, and s is the target SNR.

The base station 805 may select a code rate for an initial transmission (the first code rate) at 830. The first code rate may be selected to maximize the throughput under the constraint of the selected second code rate, which may be expressed as shown in Equation (2) :

where r _1st is the first code rate.

The base station 805 may determine a ratio of resource allocation between the retransmission and the initial transmission at 835. The base station 805 may quantize the ratio of resource allocation.

The base station 805 may transmit an indication to use a second number of resource blocks for the retransmission 840 to the UE 810. The indication 840 may be, for example, a resource ratio as described with reference to FIG. 3, a TBS table as described with reference to FIG. 4, a mode indicator as described with reference to FIG. 6, a retransmission configuration as described with reference to FIG. 7, or a combination thereof.

In one example, calculating code rates for an initial transmission and a retransmission may involve an analysis of BLER curves. For example, a plurality of BLER curves may be simulated as functions of SNR. Each BLER curve may correspond\ to a different code rate. In one example, a target SNR may be identified as 5 dB for the curve whose target BLER is 10 ^-5. A corresponding BLER curve may be selected from the plurality of BLER curves. The code rate to which the selected BLER curve corresponds (in one example, 0.175) , may be selected as the second code rate (for the retransmission) .

Once the second code rate is selected, the first code rate may be selected, for example, in accordance with Equation (2) . By using the first code rate, as determined via Equation (2) , the spectrum efficiency of the initial transmission and retransmission may rise. In one example, by using the optimized initial transmission, an average spectrum efficiency gain of 30% may be observed.

In one example, the ratio of resource allocations for a retransmission with respect to an initial transmission may vary by SNR. In some aspects, the ratio may be quantized, meaning that it may vary from, for example, a higher ratio for low values of SNR, to a lower ratio for high values of SNR. For example, the resource ratio may be at a value of three for values of SNR ranging from three to seven dB, but may decrease to a value of two for values of SNR ranging from eight to ten dB. Other ratios and relationships to SNR may be used as well.

FfG. 9 shows a block diagram 900 of a device 905 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 905 may be an example of aspects of a UE 115 as described herein. The device 905 may include a receiver 910, a communications manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 910 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 resource allocation optimization for an ultra-reliable low latency communications package, etc.) . Information may be passed on to other components of the device 905. The receiver 910 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The receiver 910 may utilize a single antenna or a set of antennas.

The communications manager 915 may transmit, by a UE, a first uplink communication using a first number of RBs, receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and transmit the second uplink communication based on the indication. The communications manager 915 may be an example of aspects of the communications manager 1210 described herein.

The communications manager 915, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 915, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 915, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 915, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 915, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 920 may transmit signals generated by other components of the device 905. In some examples, the transmitter 920 may be collocated with a receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The transmitter 920 may utilize a single antenna or a set of antennas.

FfG. 10 shows a block diagram 1000 of a device 1005 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 1005 may be an example of aspects of a device 905 or a UE 115 as described herein. The device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1035. The device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1010 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 resource allocation optimization for an ultra-reliable low latency communications package, etc.) . Information may be passed on to other components of the device 1005. The receiver 1010 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The receiver 1010 may utilize a single antenna or a set of antennas.

The communications manager 1015 may be an example of aspects of the communications manager 915 as described herein. The communications manager 1015 may include a first uplink communication scheduler 1020, a RB indication processor 1025, and a second uplink communication scheduler 1030. The communications manager 1015 may be an example of aspects of the communications manager 1210 described herein.

The first uplink communication scheduler 1020 may transmit, by a UE, a first uplink communication using a first number of RBs.

The RB indication processor 1025 may receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission.

The second uplink communication scheduler 1030 may transmit the second uplink communication based on the indication.

The transmitter 1035 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1035 may be collocated with a receiver 1010 in a transceiver module. For example, the transmitter 1035 may be an example of aspects of the transceiver 1220 described with reference to FIG. 12. The transmitter 1035 may utilize a single antenna or a set of antennas.

FfG. 11 shows a block diagram 1100 of a communications manager 1105 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The communications manager 1105 may be an example of aspects of a communications manager 915, a communications manager 1015, or a communications manager 1210 described herein.. The communications manager 1105 may include a first uplink communication scheduler 1110, a RB indication processor 1115, and a second uplink communication scheduler 1120. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The first uplink communication scheduler 1110 may transmit, by a UE, a first uplink communication using a first number of RBs.

The RB indication processor 1115 may receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission. In some examples, the RB indication processor 1115 may receive the indication in DCI associated with the first uplink communication.

In some examples, the RB indication processor 1115 may receive a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs. In some examples, the RB indication processor 1115 may receive a number of bits, where different bit combinations correspond to different predefined resource ratios.

In some examples, the RB indication processor 1115 may receive a TBS adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs. In some cases, the scalar value corresponds to a modulation and coding scheme identified in the TBS table. In some cases, the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.

In some examples, the RB indication processor 1115 may receive a mode indicator in DCI, where the mode indicator indicates a mode for determining the different number of RBs. In some cases, the mode indicator is associated with a quantized resource ratio that is based on a SNR.

In some examples, the RB indication processor 1115 may receive a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions. In some examples, the RB indication processor 1115 may receive the first configuration indication and the second configuration indication via a semi-persistent scheduling communication. In some cases, the first configuration includes one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions. In some cases, the second configuration includes one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions.

The second uplink communication scheduler 1120 may transmit the second uplink communication based on the indication.

FfG. 12 shows a diagram of a system 1200 including a device 1205 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 1205 may be an example of or include the components of device 905, device 1005, or a UE 115 as described herein. The device 1205 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1210, an I/O controller 1215, a transceiver 1220, an antenna 1225, memory 1230, and a processor 1240. These components may be in electronic communication via one or more buses (e.g., bus 1245) .

The communications manager 1210 may transmit, by a UE, a first uplink communication using a first number of RBs, receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and transmit the second uplink communication based on the indication.

The I/O controller 1215 may manage input and output signals for the device 1205. The I/O controller 1215 may also manage peripherals not integrated into the device 1205. In some cases, the I/O controller 1215 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 1215 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 1215 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 1215 may be implemented as part of a processor. In some cases, a user may interact with the device 1205 via the I/O controller 1215 or via hardware components controlled by the I/O controller 1215.

The transceiver 1220 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1220 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1220 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1225. However, in some cases the device may have more than one antenna 1225, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1230 may include RAM and ROM. The memory 1230 may store computer-readable, computer-executable code 1235 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1230 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1240 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, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1240 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 1240. The processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting resource allocation optimization for an ultra-reliable low latency communications package) .

The code 1235 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1235 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1235 may not be directly executable by the processor 1240 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FfG. 13 shows a block diagram 1300 of a device 1305 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 1305 may be an example of aspects of a base station 105 as described herein. The device 1305 may include a receiver 1310, a communications manager 1315, and a transmitter 1320. The device 1305 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1310 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 resource allocation optimization for an ultra-reliable low latency communications package, etc.) . Information may be passed on to other components of the device 1305. The receiver 1310 may be an example of aspects of the transceiver 1620 described with reference to FIG. 16. The receiver 1310 may utilize a single antenna or a set of antennas.

The communications manager 1315 may receive, by a base station and from a UE, a first uplink communication using a first number of RBs, transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and receive the second uplink communication based on the indication. The communications manager 1315 may be an example of aspects of the communications manager 1610 described herein.

The communications manager 1315, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1315, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1315, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1315, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1315, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1320 may transmit signals generated by other components of the device 1305. In some examples, the transmitter 1320 may be collocated with a receiver 1310 in a transceiver module. For example, the transmitter 1320 may be an example of aspects of the transceiver 1620 described with reference to FIG. 16. The transmitter 1320 may utilize a single antenna or a set of antennas.

FfG. 14 shows a block diagram 1400 of a device 1405 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 1405 may be an example of aspects of a device 1305 or a base station 115 as described herein. The device 1405 may include a receiver 1410, a communications manager 1415, and a transmitter 1435. The device 1405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1410 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 resource allocation optimization for an ultra-reliable low latency communications package, etc.) . Information may be passed on to other components of the device 1405. The receiver 1410 may be an example of aspects of the transceiver 1620 described with reference to FIG. 16. The receiver 1410 may utilize a single antenna or a set of antennas.

The communications manager 1415 may be an example of aspects of the communications manager 1315 as described herein. The communications manager 1415 may include a first uplink communication processor 1420, a RB indication scheduler 1425, and a second uplink communication processor 1430. The communications manager 1415 may be an example of aspects of the communications manager 1610 described herein.

The first uplink communication processor 1420 may receive, by a base station and from a UE, a first uplink communication using a first number of RBs.

The RB indication scheduler 1425 may transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission.

The second uplink communication processor 1430 may receive the second uplink communication based on the indication.

The transmitter 1435 may transmit signals generated by other components of the device 1405. In some examples, the transmitter 1435 may be collocated with a receiver 1410 in a transceiver module. For example, the transmitter 1435 may be an example of aspects of the transceiver 1620 described with reference to FIG. 16. The transmitter 1435 may utilize a single antenna or a set of antennas.

FfG. 15 shows a block diagram 1500 of a communications manager 1505 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The communications manager 1505 may be an example of aspects of a communications manager 1315, a communications manager 1415, or a communications manager 1610 described herein.. The communications manager 1505 may include a first uplink communication processor 1510, a RB indication scheduler 1515, a second uplink communication processor 1520, a RB number determination unit 1525, a BLER curve simulator 1530, a second code rate selector 1535, a first code rate selector 1540, and a ratio selector 1545. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) . The first uplink communication processor 1510 may receive, by a base station and from a UE, a first uplink communication using a first number of RBs.

The RB indication scheduler 1515 may transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission. In some examples, the RB indication scheduler 1515 may transmit the indication in DCI associated with the first uplink communication.

In some examples, the RB indication scheduler 1515 may transmit a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs. In some examples, the RB indication scheduler 1515 may transmit a number of bits, where different bit combinations correspond to different predefined resource ratios.

In some examples, the RB indication scheduler 1515 may transmit a TBS adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs. In some cases, the scalar value corresponds to a modulation and coding scheme identified in the TBS table. In some cases, the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.

In some examples, the RB indication scheduler 1515 may transmit a mode indicator in DCI, where the mode indicator indicates a mode for determining the different number of RBs. In some cases, the mode indicator is associated with a quantized resource ratio that is based on a SNR.

In some examples, the RB indication scheduler 1515 may transmit a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions. In some examples, the RB indication scheduler 1515 may transmit the first configuration indication and the second configuration indication via a semi-persistent scheduling communication. In some cases, the first configuration includes one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions. In some cases, the second configuration includes one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions.

The second uplink communication processor 1520 may receive the second uplink communication based on the indication.

The RB number determination unit 1525 may determine the indication of the different number of RBs based on a channel condition. The BLER curve simulator 1530 may simulate a BLER curve for a set of code rates. The second code rate selector 1535 may select, based on a target channel condition, a second code rate for the second uplink communication based on the set of BLER curves. The first code rate selector 1540 may select a first code rate for the first uplink communication based on the selected second code rate. The ratio selector 1545 may select the ratio of the different number of RBs and the first number of RBs based on the second code rate and the first code rate.

FfG. 16 shows a diagram of a system 1600 including a device 1605 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The device 1605 may be an example of or include the components of device 1305, device 1405, or a base station 105 as described herein. The device 1605 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1610, a network communications manager 1615, a transceiver 1620, an antenna 1625, memory 1630, a processor 1640, and an inter-station communications manager 1645. These components may be in electronic communication via one or more buses (e.g., bus 1650) .

The communications manager 1610 may receive, by a base station and from a UE, a first uplink communication using a first number of RBs, transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission, and receive the second uplink communication based on the indication.

The network communications manager 1615 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1615 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1620 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1620 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1620 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1625. However, in some cases the device may have more than one antenna 1625, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1630 may include RAM, ROM, or a combination thereof. The memory 1630 may store computer-readable code 1635 including instructions that, when executed by a processor (e.g., the processor 1640) cause the device to perform various functions described herein. In some cases, the memory 1630 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1640 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, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1640 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1640. The processor 1640 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1630) to cause the device #{device} to perform various functions (e.g., functions or tasks supporting resource allocation optimization for an ultra-reliable low latency communications package) .

The inter-station communications manager 1645 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1645 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1645 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1635 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1635 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1635 may not be directly executable by the processor 1640 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FfG. 1T shows a flowchart illustrating a method 1700 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1705, the UE may transmit, by a UE, a first uplink communication using a first number of RBs. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by a first uplink communication scheduler as described with reference to FIGs. 9 through 12.

At 1710, the UE may receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by a RB indication processor as described with reference to FIGs. 9 through 12.

At 1715, the UE may transmit the second uplink communication based on the indication. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed by a second uplink communication scheduler as described with reference to FIGs. 9 through 12.

FfG. 18 shows a flowchart illustrating a method 1800 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The operations of method 1800 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1800 may be performed by a communications manager as described with reference to FIGs. 13 through 16. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1805, the base station may receive, by a base station and from a UE, a first uplink communication using a first number of RBs. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed by a first uplink communication processor as described with reference to FIGs. 13 through 16.

At 1810, the base station may transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed by a RB indication scheduler as described with reference to FIGs. 13 through 16.

At 1815, the base station may receive the second uplink communication based on the indication. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed by a second uplink communication processor as described with reference to FIGs. 13 through 16.

FfG. 19 shows a flowchart illustrating a method 1900 that supports resource allocation optimization for an ultra-reliable low latency communications package in accordance with aspects of the present disclosure. The operations of method 1900 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1900 may be performed by a communications manager as described with reference to FIGs. 13 through 16. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1905, the base station may simulate a BLER curve for a set of code rates. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed by a BLER curve simulator as described with reference to FIGs. 13 through 16.

At 1910, the base station may select, based on a target channel condition, a second code rate for the second uplink communication based on the set of BLER curves. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed by a second code rate selector as described with reference to FIGs. 13 through 16.

At 1915, the base station may select a first code rate for the first uplink communication based on the selected second code rate. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed by a first code rate selector as described with reference to FIGs. 13 through 16.

At 1920, the base station may select the ratio of the different number of RBs and the first number of RBs based on the second code rate and the first code rate. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed by a ratio selector as described with reference to FIGs. 13 through 16.

At 1925, the base station may receive, from a UE, a first uplink communication using a first number of RBs. The first number of RBs may be determined based at least in part on the first code rate, which the base station may have transmitted to the UE (e.g., in DCI) . The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed by a first uplink communication processor as described with reference to FIGs. 13 through 16.

At 1930, the base station may transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, where a ratio of the different number of RBs and the first number of RBs is associated with a target BLER for the retransmission. The indication may include the ratio determined at 2220. The operations of 1930 may be performed according to the methods described herein. In some examples, aspects of the operations of 1930 may be performed by a RB indication scheduler as described with reference to FIGs. 13 through 16.

At 1935, the base station may receive the second uplink communication based on the indication. The operations of 1935 may be performed according to the methods described herein. In some examples, aspects of the operations of 1935 may be performed by a second uplink communication processor as described with reference to FIGs. 13 through 16.

It should be noted that the methods described above describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs 115 with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs 115 having an association with the femto cell (e.g., UEs 115 in a closed subscriber group (CSG) , UEs 115 for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications system 100 or systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

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 referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device (PLD) , 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 conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

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, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the 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 microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc 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.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such 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) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication, comprising:

transmitting, by a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

receiving, from a base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

transmitting the second uplink communication based at least in part on the indication.
The method of claim 1, wherein receiving the indication to use the different number of RBs comprises:

receiving the indication in downlink control information (DCI) associated with the first uplink communication.
The method of claim 1, wherein receiving the indication to use the different number of RBs comprises:

receiving a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs.
The method of claim 3, wherein receiving the resource ratio comprises:

receiving a number of bits, wherein different bit combinations correspond to different predefined resource ratios.
The method of claim 1, wherein receiving the indication to use the different number of RBs comprises:

receiving a transport block size (TBS) adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs.
The method of claim 5, wherein the scalar value corresponds to a modulation and coding scheme identified in the TBS table.
The method of claim 5, wherein the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.
The method of claim 1, wherein receiving the indication to use the different number of RBs comprises:

receiving a mode indicator in downlink control information (DCI) , wherein the mode indicator indicates a mode for determining the different number of RBs.
The method of claim 8, wherein the mode indicator is associated with a quantized resource ratio that is based at least in part on a signal-to-noise ratio (SNR) .
The method of claim 1, wherein receiving the indication to use the different number of RBs comprises:

receiving a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions.
The method of claim 10, wherein:

the first configuration comprises one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions; and

the second configuration comprises one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions.
The method of claim 10, wherein receiving the indication to use the different number of RBs further comprises:

receiving the first configuration indication and the second configuration indication via a semi-persistent scheduling communication.
A method for wireless communication, comprising:

receiving, by a base station and from a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

transmitting an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

receiving the second uplink communication based at least in part on the indication.
The method of claim 13, wherein transmitting the indication to use the different number of RBs comprises:

transmitting the indication in downlink control information (DCI) associated with the first uplink communication.
The method of claim 13, wherein transmitting the indication to use the different number of RBs comprises:

transmitting a resource ratio which indicates the ratio between the different number of RBs and the first number of RBs.
The method of claim 15, wherein transmitting the resource ratio comprises:

transmitting a number of bits, wherein different bit combinations correspond to different predefined resource ratios.
The method of claim 13, wherein transmitting the indication to use the different number of RBs comprises:

transmitting a transport block size (TBS) adjustment indicator that indicates that a scalar factor from a TBS table is to be used to determine the different number of RBs.
The method of claim 17, wherein the scalar value corresponds to a modulation and coding scheme identified in the TBS table.
The method of claim 17, wherein the scalar factor from the TBS table is applied to the first number of RBs in order to determine the different number of RBs.
The method of claim 13, wherein transmitting the indication to use the different number of RBs comprises:

transmitting a mode indicator in downlink control information (DCI) , wherein the mode indicator indicates a mode for determining the different number of RBs.
The method of claim 20, wherein the mode indicator is associated with a quantized resource ratio that is based at least in part on a signal-to-noise ratio (SNR) .
The method of claim 13, wherein transmitting the indication to use the different number of RBs comprises:

transmitting a first configuration indication that a first configuration is to be used for initial transmissions and a second configuration indication that a second configuration is to be used for retransmissions.
The method of claim 22, wherein:

the first configuration comprises one or more modulation and coding schemes for initial transmissions and one or more resource allocations for initial transmissions; and

the second configuration comprises one or more modulation and coding schemes for retransmissions and one or more resource allocations for retransmissions.
The method of claim 22, wherein receiving the indication to use the different number of RBs further comprises:

transmitting the first configuration indication and the second configuration indication via a semi-persistent scheduling communication.
The method of claim 13, further comprising:

determining the indication of the different number of RBs based at least in part on a channel condition.
The method of claim 25, wherein determining the indication of the different number of RBs comprises:

simulating a BLER curve for a plurality of code rates;

selecting, based at least in part on a target channel condition, a second code rate for the second uplink communication based at least in part on the plurality of BLER curves; and

selecting a first code rate for the first uplink communication based at least in part on the selected second code rate.
The method of claim 26, further comprising:

selecting the ratio of the different number of RBs and the first number of RBs based at least in part on the second code rate and the first code rate.
An apparatus for wireless communication, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

transmit, by a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

transmit the second uplink communication based at least in part on the indication.
An apparatus for wireless communication, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, by a base station and from a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

receive the second uplink communication based at least in part on the indication.
An apparatus for wireless communication, comprising:

means for transmitting, by a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

means for receiving, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

means for transmitting the second uplink communication based at least in part on the indication.
An apparatus for wireless communication, comprising:

means for receiving, by a base station and from a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

means for transmitting an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

means for receiving the second uplink communication based at least in part on the indication.
A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

transmit, by a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

receive, from the base station, an indication to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

transmit the second uplink communication based at least in part on the indication.
A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

receive, by a base station and from a user equipment (UE) , a first uplink communication using a first number of resource blocks (RBs) ;

transmit an indication that the UE is to use a different number of RBs for a retransmission of the first uplink communication, wherein a ratio of the different number of RBs and the first number of RBs is associated with a target block error rate (BLER) for the retransmission; and

receive the second uplink communication based at least in part on the indication.