Cross-carrier random access configuration

Abstract

Methods, systems, and devices for wireless communications are described. A random access channel (RACH) opportunity may be scheduled on each component carrier (CC) of a carrier aggregation (CA) configuration including both a time division duplex (TDD) band and at least one frequency division duplex (FDD) band based on a synchronization signal / physical broadcast channel block (SSB) received in the TDD band. In some cases, the TDD band may be used to configure RACH opportunities in the same and / or different CCs. Additionally or alternatively, the FDD band may configure RACH opportunities on its uplink CC based on SSBs received on other CCs. Additionally, the RACH opportunity may be configured so that the UE avoids unavailable uplink time slots when transmitting a first RACH message in the RACH opportunity.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of PCT Application No. PCT / CN2019 / 107452, entitled “CROSS CARRIER RANDOMACCESS CONFIGURATION,” filed by CAO et al. on September 24, 2019, which is assigned to the assignee of this application.

[0003] background

[0004] The following relates generally to wireless communications, and more particularly to cross-carrier random access configurations.

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

[0006] A wireless multiple access communication system may include several base stations or network access nodes, each of which simultaneously supports communication for multiple communication devices, which may be further referred to as user equipment (UE). When connected to a base station to receive and / or transmit subsequent communications, the UE may perform a random access channel (RACH) procedure to establish a connection with the base station. Additionally, in some cases, the UE may simultaneously communicate via multiple component carriers (CCs) in a carrier aggregation (CA) configuration, wherein a RACH procedure is performed for each of the multiple CCs. An efficient technique is desired to determine configuration information for one or more messages regarding the RACH procedure(s).

[0007] Overview

[0008] The described technology relates to improved methods, systems, devices and apparatuses for supporting cross-carrier random access configuration. In general, the described technology provides a set of random access channel (RACH) opportunities for scheduling a carrier aggregation (CA) configuration for a time division duplex (TDD) band and at least one frequency division duplex (FDD) band, wherein the RACH opportunity set is based on a synchronization signal (SS) / physical broadcast channel (PBCH) block (SSB) of the TDD band. For example, a user equipment (UE) may be configured to communicate via multiple component carriers (CCs) (e.g., of a single base station or multiple base stations) according to a CA configuration, and a first RACH message for at least one CC may be transmitted during a RACH opportunity in the scheduled RACH opportunity set. In some cases, a RACH opportunity (e.g., cross-carrier scheduling) may be configured on the TDD band in a CC that is the same as or different from a CC on the TDD band. Therefore, when scheduling and configuring a RACH opportunity on the TDD band, carrier information indicating which CCs are used for the RACH opportunity set may be transmitted to the UE. Additionally or alternatively, a RACH opportunity may be configured on an uplink CC of an FDD band based on an SSB received on a different CC (e.g., a CC using a TDD band). Thus, when scheduling and configuring RACH opportunities on an FDD band, CC information indicating which corresponding CCs of the uplink CC are configured with a RACH opportunity set in the FDD band may be transmitted to the UE.

[0009] Additionally, the RACH opportunity set may avoid unavailable uplink time slots. For example, the UE may not know which time slots are unavailable, and the base station may schedule the UE to available uplink time slots via the RACH opportunity set. In some cases, the base station may transmit a time division multiplexing (TDM) pattern to the UE, and the UE may determine which uplink time slots are available or unavailable based on the TDM pattern and the scheduled RACH opportunity set. For example, when the scheduled RACH opportunity and the TDM pattern conflict, the UE may avoid transmitting the first RACH message in the uplink time slot. Additionally, when the UE attempts to retransmit the first RACH message, the base station may indicate a list of available and prohibited RACH opportunities, wherein the UE derives a backoff timer when retransmitting the first RACH message and identifies one of the available RACH opportunities based on the list. Additionally or alternatively, the UE may identify how to retransmit the first RACH message based on the TDM pattern transmitted by the base station. A technique is also provided for the UE to identify a parameter for receiving a second RACH message based on a paired frequency band for a RACH opportunity for transmitting a first RACH message and / or to identify a propagation delay for receiving the second RACH message based on a plurality of CCs. Additionally, the UE may determine a transmit power for transmitting the first RACH message based on measuring a downlink time slot corresponding to a RACH opportunity for transmitting the first RACH message.

[0010] A method for wireless communication at a UE is described. The method may include: identifying a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band; receiving a random access opportunity configuration (e.g., a RACH opportunity configuration) that schedules a set of random access opportunities (e.g., RACH opportunities) for the CC set based on an SSB of the TDD frequency band; and transmitting a first random access message (e.g., a first RACH message) for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0011] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor so that the apparatus: identifies a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band; receives a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on an SSB of the TDD frequency band; and transmits a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0012] Another apparatus for wireless communication at a UE is described. The apparatus may include means for: identifying a CA configuration for communicating with a set of CCs, the CA configuration including a TDD frequency band and at least one FDD frequency band; receiving a random access opportunity configuration for scheduling a set of random access opportunities for the set of CCs based on an SSB of the TDD frequency band; and transmitting a first random access message for the CC during a random access opportunity in the set of random access opportunities based on the random access opportunity configuration.

[0013] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: identify a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band; receive a random access opportunity configuration that schedules a random access opportunity set for the CC set based on an SSB of the TDD frequency band; and transmit a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0014] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, receiving a random access timing configuration may include operations, features, apparatus, or instructions for the following actions: receiving a random access timing configuration in a TDD band, wherein the random access timing set may be configured in at least one CC in at least one FDD band, TDD band, or a combination thereof.

[0015] In some examples of the methods, devices, and non-transitory computer-readable media described herein, receiving a random access opportunity configuration may further include operations, features, means, or instructions for receiving carrier information indicating which CCs may be used for a set of random access opportunities.

[0016] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, receiving a random access timing configuration may further include operations, features, apparatus, or instructions for the following actions: receiving a random access timing configuration via a radio resource control (RRC) configuration for system information, a downlink control information (DCI) configuration for a random access procedure, or a combination thereof.

[0017] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, receiving a random access timing configuration may include operations, features, apparatus, or instructions for the following actions: receiving a random access timing configuration in at least one FDD frequency band, wherein one or more random access timings in the random access timing set may be configured in an uplink CC in at least one FDD frequency band, a TDD frequency band, or a combination thereof.

[0018] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for determining the uplink CC based on the SSB of the TDD band, an additional SSB of a CC different from the uplink CC, or a combination thereof.

[0019] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, receiving a random access opportunity configuration may further include operations, features, apparatus, or instructions for the following actions: receiving CC information indicating which corresponding CCs in the uplink CCs may be configured with one or more random access opportunities in the at least one FDD frequency band.

[0020] In some examples of the methods, devices (apparatus) and non-transitory computer-readable media described herein, the random access opportunity configuration includes a frequency configuration for a random access opportunity set, a time configuration for a random access opportunity set, a sequence configuration for a random access opportunity set, or a combination thereof.

[0021] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for receiving a second random access message (eg, a second RACH message) based on transmitting the first random access message.

[0022] Some examples of the methods, devices (equipment), and non-transitory computer-readable media described herein may further include operations, features, devices, or instructions for the following actions: determining a propagation delay based on a CC on which a first random access message can be transmitted and an additional CC on which a second random access message can be received; and monitoring a time window based on the propagation delay to look for a second random access message.

[0023] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the propagation delay may be determined based on a first timing advance group (TAG) for the CC and a second TAG for the additional CC, the first TAG being the same as or different from the second TAG.

[0024] In some examples of the methods, devices, and non-transitory computer-readable media described herein, a second random access message may be received on an uplink CC that may be paired with a TDD band or at least one FDD band based on a CC on which a first random access message may be transmitted.

[0025] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: measuring the signal quality of a downlink CC corresponding to a CC used to transmit a first random access message; and determining a transmit power for transmitting the first random access message based on the measured signal quality.

[0026] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the downlink CC may be in a TDD frequency band or at least one FDD frequency band.

[0027] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for receiving an indication of an uplink time slot for transmitting a first random access message.

[0028] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for: receiving a TDM pattern for transmitting a first random access message; and determining one or more available random access opportunities based on the TDM pattern, wherein the first random access message can be transmitted in at least one of the one or more available random access opportunities.

[0029] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for: determining that a first random access message is to be retransmitted; and transmitting the first random access message a second time based on the determination regarding the retransmission and the TDM mode.

[0030] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the TDM mode may be received via an RRC message, a DCI configuration, or a combination thereof.

[0031] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for the following actions: receiving a media access control (MAC) control element (CE) including a random access radio network temporary identifier; receiving a list of available and unavailable random access opportunities within the MAC CE; determining a backoff timer and a retransmission configuration for a first random access message based on the list of available and unavailable random access opportunities; and transmitting the first random access message a second time based on the backoff timer and the retransmission configuration.

[0032] A method for wireless communication at a base station is described. The method may include: identifying a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band; transmitting a random access opportunity configuration (e.g., a RACH opportunity configuration) of a set of random access opportunities (e.g., RACH opportunities) scheduled for the CC set based on an SSB of the TDD frequency band; and receiving a first random access message (e.g., a first RACH message) for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0033] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor so that the apparatus: identifies a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band; transmits a random access opportunity configuration of a random access opportunity set for the CC set based on an SSB of the TDD frequency band; and receives a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0034] Another apparatus for wireless communication at a base station is described. The apparatus may include means for: identifying a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band; transmitting a random access opportunity configuration of a random access opportunity set scheduled for the CC set based on an SSB of the TDD frequency band; and receiving a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0035] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to perform the following operations: identifying a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band; transmitting a random access opportunity configuration of a random access opportunity set scheduled for the CC set based on an SSB of the TDD frequency band; and receiving a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0036] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, transmitting a random access timing configuration may include operations, features, apparatus, or instructions for the following actions: transmitting a random access timing configuration in a TDD band, wherein the random access timing set may be configured in at least one CC in at least one FDD band, TDD band, or a combination thereof.

[0037] In some examples of the methods, devices, and non-transitory computer-readable media described herein, transmitting a random access opportunity configuration may include operations, features, means, or instructions for transmitting carrier information indicating which CCs may be used for a set of random access opportunities.

[0038] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, transmitting a random access timing configuration may include operations, features, apparatus, or instructions for the following actions: transmitting a random access timing configuration via an RRC configuration for system information, a DCI configuration for a random access procedure, or a combination thereof.

[0039] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, transmitting a random access opportunity configuration may include operations, features, apparatus, or instructions for the following actions: transmitting a random access opportunity configuration in at least one FDD frequency band, wherein one or more random access opportunities in the random access opportunity set may be configured in an uplink CC in at least one FDD frequency band, a TDD frequency band, or a combination thereof.

[0040] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for determining the uplink CC based on the SSB of the TDD band, an additional SSB of a CC different from the uplink CC, or a combination thereof.

[0041] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, transmitting a random access opportunity configuration may further include operations, features, apparatus, or instructions for the following actions: transmitting CC information indicating which corresponding CCs in the uplink CCs may be configured with one or more random access opportunities in the at least one FDD frequency band.

[0042] In some examples of the methods, devices (apparatus) and non-transitory computer-readable media described herein, the random access opportunity configuration includes a frequency configuration for a random access opportunity set, a time configuration for a random access opportunity set, a sequence configuration for a random access opportunity set, or a combination thereof.

[0043] Some examples of the methods, apparatus (equipment), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a second random access message (eg, a second RACH message) based on receiving the first random access message.

[0044] In some examples of the methods, devices, and non-transitory computer-readable media described herein, a second random access message may be transmitted on an uplink CC that may be paired with a TDD band or at least one FDD band based on a CC on which a first random access message may be received.

[0045] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for: determining one or more available uplink time slots for the UE to transmit a first random access message; and transmitting an indication of an uplink time slot in the one or more available uplink time slots.

[0046] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: transmitting a TDM pattern for the UE to transmit a first random access message, wherein the first random access message can be received based on the TDM pattern.

[0047] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for the following actions: receiving the first random access message for a second time based on the TDM mode.

[0048] In some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein, the TDM mode may be transmitted via an RRC message, a DCI configuration, or a combination thereof.

[0049] Some examples of the methods, devices (apparatus), and non-transitory computer-readable media described herein may further include operations, features, apparatus, or instructions for: transmitting a MAC CE including a random access radio network temporary identifier; transmitting a list of available and unavailable random access opportunities within the MAC CE; and receiving a first random access message for a second time based on the list of available and unavailable random access opportunities. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1

[0013] An example of a system for wireless communication supporting cross-carrier random access configuration in accordance with aspects of the present disclosure is illustrated.

[0052] Figure 2An example of a wireless communication system supporting cross-carrier random access configuration in accordance with aspects of the present disclosure is illustrated.

[0053] Figure 3 An example of a process flow to support cross-carrier random access configuration in accordance with aspects of the present disclosure is illustrated.

[0054] Figure 4 and 5 A block diagram of a device supporting cross-carrier random access configuration according to aspects of the present disclosure is shown.

[0055] Figure 6 A block diagram of a user equipment (UE) communications manager supporting cross-carrier random access configurations is shown in accordance with aspects of the present disclosure.

[0056] Figure 7 A diagram of a system including a device supporting cross-carrier random access configuration is shown in accordance with aspects of the present disclosure.

[0057] Figure 8 and 9 A block diagram of a device supporting cross-carrier random access configuration according to aspects of the present disclosure is shown.

[0058] Fig.10 A block diagram of a base station communication manager supporting cross-carrier random access configurations according to aspects of the present disclosure is shown.

[0059] Fig.11 A diagram of a system including a device supporting cross-carrier random access configuration is shown in accordance with aspects of the present disclosure.

[0060] Figures 12 to 17 A flow chart of a method for supporting cross-carrier random access configuration according to various aspects of the present disclosure is shown.

[0061] Detailed Description

[0062] In some wireless communication systems, user equipment (UE) may be configured to communicate via multiple component carriers (CC) simultaneously based on carrier aggregation (CA) configuration. Some CA configurations support both time division duplex (TDD) and frequency division duplex (FDD) CCs or bands. However, TDD and FDD bands may use different subcarrier spacings (SCS), which results in different slot sizes for TDD and FDD bands. In this way, trying to configure different random access channels (RACH) opportunities on each of the TDD and FDD bands may cause problems. For example, the RACH opportunity on the TDD uplink time slot may have a longer waiting time based on limited uplink resources (e.g., based on the fact that the uplink time slot does not often appear in the TDD band, the UE may need a longer time to transmit the first RACH message). Additionally, for the RACH opportunity on the FDD uplink time slot, the TDD uplink time slot may interfere with the FDD uplink time slot, thereby hindering the ability to schedule the RACH opportunity consistently on both the FDD and TDD bands at the same time.

[0063] As described herein, to alleviate these issues, instead of scheduling RACH opportunities on each CC (in an FDD or TDD band) based on synchronization signal (SS) / physical broadcast channel (PBCH) blocks (SSBs) received on each CC, RACH opportunities may be scheduled on each CC based on SSBs received in the TDD band / spectrum. In some cases, the TDD band may be used to configure RACH opportunities in the same and / or different CCs (e.g., cross-carrier scheduling). Additionally or alternatively, the FDD band may configure RACH opportunities on its uplink CC based on SSBs received on other CCs (e.g., RACH opportunities are configured on the FDD band but based on SSBs received on a CC different from the uplink CC / FDD band).

[0064] The RACH opportunity may be configured so that the UE avoids unavailable uplink time slots when transmitting the first RACH message in the RACH opportunity (e.g., based on the base station indicating which time slot will be used to transmit the RACH message, based on the time division multiplexing (TDM) mode used by the UE to determine which time slots are unavailable, etc.). Additionally, the UE may retransmit the first RACH message based on a list of available / prohibited RACH opportunities included by the base station when instructing the UE to retransmit the first RACH message, or based on the TDM mode notified when the base station configures the RACH opportunity. In some cases, the UE may determine when and where to receive the RACH response message (e.g., based on a monitoring window that takes into account propagation differences, paired frequency bands for uplink RACH opportunities, etc.), and may determine the transmit power used to transmit the first RACH message (e.g., by measuring the corresponding downlink time slots in which the RACH opportunity is configured).

[0065] Various aspects of the present disclosure are initially described in the context of wireless communication systems. Additionally, various aspects of the present disclosure are illustrated by additional wireless communication systems and process flows. Various aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow diagrams related to cross-carrier random access configurations.

[0066] Figure 1 An example of a wireless communication system 100 supporting cross-carrier random access configuration according to various aspects of the present disclosure is illustrated. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some cases, the wireless communication 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.

[0067] The base station 105 may communicate wirelessly with the UE 115 via one or more base station antennas. The base station 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 Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a Home Node B, a Home Evolved Node B, or some other suitable terminology. The wireless communication system 100 may include different types of base stations 105 (e.g., macro cell base stations or small cell base stations). The UE 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, etc.).

[0068] Each base station 105 may be associated with a particular geographic coverage area 110 in which it supports communications with various UEs 115. Each base station 105 may provide communications coverage for a respective geographic coverage area 110 via a communications link 125, and the communications link 125 between the base station 105 and the UE 115 may utilize one or more carriers. The communications link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. Downlink transmissions may also be referred to as forward link transmissions, and uplink transmissions may also be referred to as reverse link transmissions.

[0069] The geographic coverage area 110 of the base station 105 may be divided into sectors that constitute a portion of the geographic coverage area 110, and each sector may be associated with a cellular cell. For example, each base station 105 may provide communication coverage for a macrocellular cell, a small cellular cell, a hotspot, or other types of cellular cells, or various combinations thereof. In some examples, the base station 105 may be mobile and therefore provide communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and the overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or different base stations 105. The wireless communication 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.

[0070] The term "cell" refers to a logical communication entity used to communicate with base station 105 (e.g., on a carrier), and may be associated with an identifier to distinguish adjacent cells operating via the same or different carriers (e.g., physical cell identifier (PCID), virtual cell identifier (VCID)). In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types that may provide access to different types of devices (e.g., machine type communication (MTC), narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), or others). In some cases, the term "cell" may refer to a portion (e.g., a sector) of a geographic coverage area 110 on which the logical entity operates.

[0071] Each UE 115 can be dispersed throughout the wireless communication system 100, and each UE 115 can be stationary or mobile. UE 115 can 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 term, wherein "device" can also be referred to as a unit, a station, a terminal, or a client. UE 115 can 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, UE 115 can 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, etc., which can be implemented in various items (such as electrical appliances, vehicles, meters, etc.).

[0072] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with 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 the information to a central server or application, which may utilize the information or present the information to a person interacting with the program or application. Some UEs 115 may be designed to collect information or implement automated behavior of machines. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, health care monitoring, field survival monitoring, weather and geographic event monitoring, queue management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0073] Some UEs 115 may be configured to employ a reduced power consumption mode of operation, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but not simultaneous transmission and reception). In some examples, half-duplex communication may be performed with a reduced peak rate. Other power saving techniques for UE 115 include entering a power saving "deep sleep" mode when not engaged in active communications, or operating over a limited bandwidth (e.g., in accordance with narrowband communications). In some cases, UE 115 may be designed to support critical functions (e.g., mission critical functions), and the wireless communication system 100 may be configured to provide ultra-reliable communications for these functions.

[0074] In some cases, UE 115 may also be able to communicate directly with other UE 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more UEs in a group of UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105, or may not be able to receive transmissions from the base station 105 for other reasons. In some cases, each group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 transmits to each other UE 115 in the group. In some cases, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between each UE 115 without involving the base station 105.

[0075] The base stations 105 may communicate with the core network 130 and with each other. For example, the base stations 105 may interface with the core network 130 via a backhaul link 132 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other over a backhaul link 134 (e.g., via X2, Xn, or other interfaces) directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130).

[0076] 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 layer (e.g., control plane) functions such as mobility, authentication, and bearer management of UEs 115 served by base stations 105 associated with the EPC. User IP packets may be delivered through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation and other functions. The P-GW may be connected to network operator IP services. Operator IP services may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet switched (PS) streaming services.

[0077] At least some network devices (such as base stations 105) may include subcomponents, such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity may communicate with each UE 115 through a number of other access network transport entities, which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). In some configurations, the 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 merged into a single network device (e.g., base station 105).

[0078] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). In general, the 300 MHz to 3 GHz region is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths are in the range of from about 1 decimeter to 1 meter long. UHF waves may be blocked or redirected by buildings and environmental features. However, these waves may penetrate various structures sufficiently for macro cells to provide services to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 km) compared to transmission using lower frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0079] The wireless communication system 100 may also operate in the Super High Frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as centimeter bands. The SHF region includes frequency bands that may be opportunistically used by devices that may be able to tolerate interference from other users, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band.

[0080] The wireless communication system 100 may also operate in the extremely high frequency (EHF) division of the spectrum (e.g., from 30 GHz to 300 GHz), which is also referred to as the millimeter band. In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antenna of the corresponding device may be even smaller and more closely spaced than the UHF antenna. In some cases, this may facilitate the use of antenna arrays within the UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The technology disclosed herein may be adopted across transmissions using one or more different frequency divisions, and the use of frequency bands specified across these frequency divisions may differ by country or regulatory agency.

[0081] In some cases, the wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (such as a 5 GHz ISM band). When operating in an unlicensed radio frequency spectrum band, wireless devices (such as base stations 105 and UE 115) may employ a listen-before-talk (LBT) procedure to ensure that the frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on carrier aggregation configuration (e.g., LAA) in coordination with component carriers operating in licensed bands. 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 the two.

[0082] In some examples, the base station 105 or the 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) communication, or beamforming. For example, the wireless communication system 100 may use a transmission scheme between a transmitting device (e.g., the base station 105) and a receiving device (e.g., the UE 115), wherein the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communication may employ multipath signal propagation to increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. For example, the transmitting device may transmit multiple signals via different antennas or different antenna combinations. Similarly, the receiving device may receive multiple signals via different antennas or different antenna combinations. Each of these 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 for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0083] 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 direct an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array so that signals propagating at a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the transmitting device or the receiving device applying a particular amplitude and phase shift to the signal carried via each antenna element associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0084] In one example, the base station 105 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE 115. For example, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by the base station 105 in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different transmission directions. The transmissions in different beam directions may be used (e.g., by the base station 105 or a receiving device, such as the UE 115) to identify the beam direction used by the base station 105 for subsequent transmission and / or reception.

[0085] Some signals, such as data signals associated with a particular recipient device, may be transmitted by base station 105 in a single beam direction (e.g., a direction associated with a recipient device, such as UE 115). In some examples, a beam direction associated with transmissions along a single beam direction may be determined based at least in part on signals transmitted in different beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions, and UE 115 may report to base station 105 an indication of the signals received by it with the highest signal quality or other acceptable signal quality. Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may use similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction used by UE 115 for subsequent transmission or reception) or for transmitting signals in a single direction (e.g., for transmitting data to a recipient device).

[0086] A receiving device (e.g., UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105. For example, the receiving device may try multiple receive directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, or processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receive beams or receive directions. In some examples, the receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal). A 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 the highest signal strength, highest signal-to-noise ratio, or other acceptable signal quality based at least in part on listening according to multiple beam directions).

[0087] In some cases, the antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays that 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, the antennas or antenna arrays associated with a base station 105 may be located at different geographic locations. A base station 105 may have an antenna array having several rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

[0088] In some cases, the wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer may be IP-based. The radio link control (RLC) layer may perform packet segmentation and reassembly to communicate on a logical channel. The media access control (MAC) layer may perform priority handling and multiplex logical channels into transport channels. The MAC layer may also use a hybrid automatic repeat request (HARQ) to provide retransmission of the MAC layer, thereby improving link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide the establishment, configuration and maintenance of an RRC connection for a radio bearer that supports user plane data between UE115 and base station 105 or core network 130. At the physical layer, transport channels may be mapped to physical channels.

[0089] In some cases, UE 115 and base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. HARQ feedback is a technique that increases the likelihood of correctly receiving data on communication link 125. HARQ may include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput of the MAC layer in poor radio conditions (e.g., signal-to-noise ratio conditions). In some cases, a wireless device may support simultaneous slot HARQ feedback, where the device may provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0090] The time interval in LTE or NR can be represented by a basic time unit (which may refer to a sampling period T, for example). s =1 / 30,720,000 seconds). The time intervals of the communication resources 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 =307,200T s . A radio frame 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 slot 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 a 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 minimum scheduling unit of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In other cases, the minimum scheduling unit of the wireless communication system 100 may be shorter than a subframe or may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI) or in a selected component carrier using sTTI).

[0091] In some wireless communication systems, a time slot may be further divided into a plurality of mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the minimum scheduling unit. For example, each symbol may vary in duration depending on the subcarrier spacing or the operating frequency band. Further, some wireless communication systems may implement time slot aggregation, wherein a plurality of time slots or mini-slots are aggregated together and used for communication between UE 115 and base station 105.

[0092] The term "carrier" refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications on the communication link 125. For example, a carrier of the communication link 125 may include a portion of a radio frequency spectrum band that operates according to a physical layer channel 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 predefined frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel grid for discovery by a UE 115. A carrier may be downlink or uplink (e.g., in FDD mode), or configured to carry downlink communications and uplink communications (e.g., in TDD mode). In some examples, a signal waveform transmitted on a carrier may include multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)).

[0093] For different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR), the organizational structure of the carrier can be different. For example, the communication on the carrier can be organized according to TTIs or time slots, each of which can include user data and control information or signaling to support decoding of the user data. The carrier can also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling to coordinate the operation of the carrier. In some examples (e.g., in a carrier aggregation configuration), the carrier may also have acquisition signaling or control signaling to coordinate the operation of other carriers.

[0094] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using 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 in a cascaded manner between different control regions (e.g., between a common control region or a common search space and one or more UE-specific control regions or UE-specific search spaces).

[0095] 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 the "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of several predetermined bandwidths of a carrier for 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 to operate on part or all of the carrier bandwidth. In other examples, some UEs 115 may be configured to operate using a narrowband protocol type associated with a predefined portion or range (e.g., a set of subcarriers or RBs) within a carrier (e.g., an "in-band" deployment of a narrowband protocol type).

[0096] In a system using MCM technology, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the 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 received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 can be. In a MIMO system, wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and space resources (e.g., space layers), and the use of multiple space layers may further increase the data rate of communication with UE 115.

[0097] A device (e.g., base station 105 or UE 115) of wireless communication system 100 may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configurable to support communication on one of a set of carrier bandwidths. In some examples, wireless communication system 100 may include base stations 105 and / or UEs 115 that support simultaneous communication via carriers associated with more than one different carrier bandwidths.

[0098] The wireless communication system 100 may support communication with the UE 115 on multiple cells or carriers, a feature that may be referred to as CA or multi-carrier operation. The UE 115 may be configured with multiple downlink CCs and one or more uplink CCs according to the CA configuration. CA may be used with both FDD CCs and TDD CCs.

[0099] In some cases, the wireless communication system 100 may utilize an enhanced CC (eCC). An eCC may be characterized by one or more features including a wider carrier or frequency channel bandwidth, a shorter symbol duration, a shorter TTI duration, or a modified control channel configuration. In some cases, an eCC may be associated with a CA configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal or non-ideal backhaul links). An eCC may also be configured to be used in an unlicensed spectrum or a shared spectrum (e.g., where more than one operator is allowed to use the spectrum). An eCC characterized by a wide carrier bandwidth may include one or more segments that may be utilized by a UE 115 that is not capable of monitoring the entire carrier bandwidth or is otherwise configured to use a limited carrier bandwidth (e.g., to save power).

[0100] In some cases, an eCC may utilize a different symbol duration than other CCs, which may include using a reduced symbol duration compared to the symbol duration of other CCs. A shorter symbol duration may be associated with an increased spacing (e.g., a subcarrier spacing (SCS)) between adjacent subcarriers. A device utilizing an eCC, such as a UE 115 or a base station 105, may transmit a wideband signal (e.g., based on a frequency channel or carrier bandwidth of 20, 40, 60, 80 MHz, etc.) with a reduced symbol duration (e.g., 16.67 microseconds). A TTI in an eCC may include one or more symbol periods. In some cases, the TTI duration (i.e., the number of symbol periods in a TTI) may be variable.

[0101] The wireless communication system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, etc. The flexibility of eCC symbol duration and SCS may allow the use of eCC across multiple spectrums. In some examples, NR shared spectrum may improve spectrum utilization and spectrum efficiency, particularly through dynamic vertical (e.g., across frequency domain) and horizontal (e.g., across time domain) sharing of resources.

[0102] A UE 115 attempting to access a wireless network may perform an initial cell search by detecting a primary synchronization signal (PSS) from a base station 105. The PSS may enable synchronization of slot timing and may indicate a physical layer identity value. The UE 115 may then receive a secondary synchronization signal (SSS). The SSS may enable radio frame synchronization and may provide a cell identity value that may be combined with a physical layer identity value to identify the cell. The SSS may also enable detection of duplex mode and cyclic prefix length. Some systems (such as TDD systems) may transmit SSS but not PSS. Both PSS and SSS may be located in the center 62 and 72 subcarriers of a carrier, respectively. In some cases, the base station 105 may use multiple beams to transmit synchronization signals (e.g., PSS, SSS, etc.) through a cellular coverage area in a beam sweeping manner. In some cases, PSS, SSS, and / or broadcast information (e.g., PBCH) may be transmitted in different SS blocks on corresponding directional beams, wherein one or more SS blocks may be included in an SS burst.

[0103] After receiving the PSS and SSS, the UE 115 may receive a master information block (MIB), which may be transmitted in the PBCH. The MIB may include system bandwidth information, SFN, and physical HARQ indicator channel (PHICH) configuration. After decoding the MIB, the UE 115 may receive one or more system information blocks (SIBs). For example, SIB1 may include cell access parameters and scheduling information for other SIBs. Decoding SIB1 may enable the UE 115 to receive SIB2. SIB2 may include RRC configuration information related to RACH procedures, paging, PUCCH, PUSCH, power control, SRS, and cell barring.

[0104] After completing the initial cell synchronization, the UE 115 may decode the MIB, SIB1, and SIB2 before accessing the network. The MIB may be transmitted on the PBCH and may utilize the first 4 OFDM symbols of the second slot of the first subframe of each radio frame. It may use the middle 6 RBs (72 subcarriers) in the frequency domain. The MIB carries some important pieces of information about the UE's initial access, including the downlink channel bandwidth in RBs, PHICH configuration (duration and resource assignment), and SFN. A new MIB may be broadcast every fourth radio frame (SFN mod 4=0) and rebroadcast every frame (10ms). Each repetition is scrambled with a different scrambling code.

[0105] After reading the MIB (new version or copy), the UE 115 may try different phases of the scrambling code until it obtains a successful CRC check. The phase of the scrambling code (0, 1, 2, or 3) may enable the UE 115 to identify which of the four repetitions has been received. Thus, the UE 115 may determine the current SFN by reading the SFN in the decoded transmission and adding the scrambling code phase. After receiving the MIB, the UE may receive one or more SIBs. Different SIBs may be defined according to the type of system information communicated. The new SIB1 may be transmitted in the fifth subframe in every eighth frame (i.e., SFN mod 8=0) and rebroadcast every other frame (20ms). SIB1 includes access information (including cell identity information), and it may indicate whether the UE is allowed to camp on a cell. SIB1 also includes cell selection information (or cell selection parameters). Additionally, SIB1 includes scheduling information about other SIBs. SIB2 may be dynamically scheduled based on the information in SIB1 and includes access information and parameters related to common and shared channels. The periodicity of SIB2 may be set to 8, 16, 32, 64, 128, 256 or 512 radio frames.

[0106] After the UE 115 decodes SIB2, the UE 115 may transmit a RACH preamble (e.g., message 1 (Msg1) in a four-step RACH procedure) to the base station 105. For example, the RACH preamble may be randomly selected from a set of 64 predetermined sequences. The random selection may enable the base station 105 to distinguish between multiple UEs 115 simultaneously attempting to access the system. The base station 105 may respond with a random access response (a second message (msg2)) that provides an uplink resource grant, a timing advance, and a temporary cell radio network temporary identifier (C-RNTI). The UE 115 may then transmit an RRC connection request (e.g., a third message (Msg3)) together with a temporary mobile subscriber identity (TMSI) (if the UE 115 has previously been connected to the same wireless network) or a random identifier. The RRC connection request may also indicate the reason why the UE 115 is connected to the network (e.g., emergency, signaling, data exchange, etc.). The base station 105 may respond to the connection request with a contention resolution message (a fourth message (Msg4)) addressed to the UE 115, which may provide a new C-RNTI. If the UE 115 receives the contention resolution message with the correct identity, the UE 115 may continue with the RRC setup. If the UE 115 does not receive the contention resolution message (e.g., in the presence of a collision with another UE 115), the UE 115 may repeat the RACH procedure by transmitting a new RACH preamble. Such message exchanges between the UE 115 and the base station 105 for random access may be referred to as a four-step RACH procedure.

[0107] In other examples, a two-step RACH procedure may be performed for random access. For example, a wireless device operating in a licensed spectrum or an unlicensed spectrum within the wireless communication system 100 may initiate a two-step RACH procedure to reduce delays in establishing communications with the base station 105 (e.g., compared to a four-step RACH procedure). In some cases, the two-step RACH procedure may operate regardless of whether the wireless device (e.g., UE 115) has a valid timing advance (TA). For example, the UE 115 may use a valid TA to coordinate the timing of its transmissions to the base station 105 (e.g., to account for propagation delays) and may receive a valid TA as part of the two-step RACH procedure. Additionally, the two-step RACH procedure may be applicable to any cell size, may work regardless of whether the RACH procedure is contention-based or contention-free, and may combine multiple RACH messages from a four-step RACH procedure. For example, the two-step RACH procedure may include a first message (eg, message A (MsgA)) combining Msg1 and Msg3 of the four-step RACH procedure and a second message (eg, message B (MsgB)) combining Msg2 and Msg4 of the four-step RACH procedure.

[0108] In some network deployment scenarios (e.g., for NR), a two-step RACH procedure and a four-step RACH procedure may be used simultaneously to meet different conditions for the system. For example, the different conditions may include capacity conditions, waiting time conditions, reliability conditions, implementation complexity specifications, etc. Therefore, different transmission opportunities that can be used for two RACH procedures or any RACH procedure can be defined. For example, different transmission opportunities may include RACH opportunities and uplink shared channel (e.g., physical uplink shared channel (PUSCH)) opportunities. RACH opportunities may include time and frequency resources allocated for physical RACH (PRACH) transmissions. Additionally, up to 64 preamble sequences may be configured for each RACH opportunity. In some cases, the two-step RACH procedure may use a RACH opportunity separate from the four-step RACH procedure, or may share a RACH opportunity with the four-step RACH procedure but use a different set of preamble sequences. Additionally or alternatively, an uplink shared channel opportunity (eg, a PUSCH opportunity) may include time and frequency resources allocated for MsgAPUSCH transmissions (eg, and / or transmissions associated with a four-step RACH procedure).

[0109] As described above, UE 115 may be configured to communicate with multiple CCs based on a CA configuration. Some CA configurations support both TDD and FDD CC / bands. Additionally, in some cases, a super uplink deployment scenario may be used for a CA configuration, where uplink CA may be used without simultaneous uplink transmissions from more than one CC. For example, a TDD CC / carrier (e.g., N78 band) may be used as a primary cell (PCell) for a CA configuration due to more available downlink resources for cross-carrier scheduling. Additionally, an FDD uplink CC may be used as a secondary cell (SCell) for a CA configuration, but may be interrupted during a TDD uplink timeslot.

[0110] When establishing a connection with each CC for the CA configuration, the UE 115 may perform a RACH procedure with the CC. Thus, the UE 115 may transmit a first RACH message (e.g., Msg1 for a four-step RACH procedure or MsgA for a two-step RACH procedure) during the RACH opportunity, as described above. In the supplementary uplink configuration, RACH opportunity configuration may be allowed for a TDD uplink CC (e.g., a normal uplink (NUL) slot, an N78 band, etc.) or an FDD uplink CC (e.g., a supplementary uplink (SUL) slot, band 1 (B1), etc.). Additionally or alternatively, for CA, RACH opportunities may be configured in both the PCell and the SCell. Conventionally, the base station 105 may schedule RACH opportunities on each CC (in an FDD or TDD band) based on the SSBs received on each CC. However, RACH opportunities may be scheduled independently of each other, which may lead to different problems.

[0111] For example, for a TDD uplink, a longer RACH wait time may occur due to limited uplink resources. For example, fewer uplink time slots may be allocated in the TDD frequency band so that the UE 115 may have fewer opportunities to transmit the first RACH message, thereby increasing the wait time for the UE 115 to start the RACH procedure. In some cases, for configurations where the uplink budget is less than the downlink budget area (e.g., a larger loss may be allowed for downlink transmissions than uplink transmissions), the UE 115 may have additional losses (e.g., similar to SUL) for transmitting the first RACH message. Additionally or alternatively, for an FDD uplink, a RACH opportunity configuration in the FDD frequency band may include a first RACH transmission and a retransmission of the first RACH message (e.g., a RACH preamble) that may be interrupted by a TDD uplink time slot.

[0112] The wireless communication system 100 may support an efficient technique for scheduling RACH opportunities on each component carrier based on SSBs received in the TDD band / spectrum configured for CA including both the TDD band and the FDD band. In some cases, the TDD band may be higher than the FDD band and more suitable for MIMO because the antenna size is smaller for TDD band transmission. For example, the TDD band may include more SSB transmissions and RACH opportunities. Therefore, in order to schedule RACH opportunities for both TDD and FDD bands, the base station 105 (e.g., or different network devices) may use the TDD spectrum to configure RACH opportunities for UE 115 at both the same CC and additional CC (e.g., using the FDD spectrum) using the TDD spectrum. Additionally, the base station 105 may configure RACH opportunities and backoff timers that take into account unavailable uplink time slots (e.g., time slots allocated to other uplink transmissions), and may notify the UE 115 of the configured RACH opportunities and backoff timers. For an FDD band, RACH opportunities may be configured on the same uplink CC using the FDD band based on SSBs received on other CCs (e.g., RACH opportunities are configured only on the FDD band, but based on SSBs received on a CC different from the uplink CC / FDD band).

[0113] Figure 2 An example of a wireless communication system 200 that supports cross-carrier random access configuration according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. The wireless communication system 200 may include a base station 105-a and a UE 115-a, which may be respectively as described above with reference to Figure 1 An example of a corresponding base station 105 and a UE 115 is described. The UE 115-a and the base station 105-a can support a CA configuration in which the UE 115-a communicates using multiple CCs simultaneously. As shown, the UE 115-a can communicate with the base station 105-a using multiple CCs (e.g., on different cells of the base station 105-a), where the multiple CCs are on a carrier 205. Additionally or alternatively, the UE 115-a can communicate with multiple base stations 105 using multiple CCs, where each CC corresponds to a different base station 105.

[0114] As described herein, a CA configuration for a UE 115-a may include both a TDD band 210 (e.g., an N78 band) and an FDD band 215 (e.g., NR Band 1 (B1)) of a carrier 205. For example, the TDD band 210 may include a number of time slots 220 across the same set of frequencies assigned to different transmission directions, and the FDD band 215 may include a number of time slots 225 having a set of frequencies assigned to one transmission direction and a set of frequencies assigned to a second frequency direction. As shown, the time slots 220 of the TDD band 210 may change between downlink time slots 230, uplink time slots 235, and SSB time slots 240 that all use the same frequencies. Downlink time slot 230 may include a number of symbols allocated for downlink transmission (e.g., 14 symbols), uplink time slot 235 may include a number of symbols allocated for uplink transmission (e.g., 14 symbols), and SSB time slot 240 may include a mix of symbols allocated for transmission (e.g., 10 symbols for downlink transmission, two (2) symbols for a guard period, and two (2) symbols for uplink transmission). Additionally or alternatively, FDD frequency band 215 may include time slots 225 in a first frequency sub-band allocated to downlink time slot 230 and a second frequency sub-band allocated to uplink time slot 235 (e.g., and blank symbols / time slots).

[0115] In order to establish a connection on each CC for CA configuration, UE 115 may perform a RACH procedure via each CC. Thus, UE 115-a may transmit a first RACH message (e.g., Msg1 for a four-step RACH procedure or MsgA for a two-step RACH procedure) during a RACH opportunity. Base station 105-a may configure RACH opportunities for UE 115-a in both TDD band 210 and FDD band 215 (e.g., on CCs in both TDD band 210 and FDD band 215), and may signal the configuration to UE 115-a before UE 115-a transmits the first RACH message. For example, base station 105-a may indicate the frequency, time, and sequence configuration for the RACH opportunity. In some cases, UE 115-a may transmit a first RACH message on one CC among multiple RACH opportunities on different CCs.

[0116] However, the TDD band 210 and the FDD band 215 may use different SCSs, which result in different slot durations for the time slots 220 and 225, respectively. For example, the TDD band 210 may use a first SCS of 30 kHz, which results in a slot duration of 0.5 ms for the time slot 220. Alternatively, the FDD band 215 may use a second SCS of 15 kHz, which results in a slot duration of 1 ms for the time slot 225. Therefore, attempts to configure different RACH opportunities on each of the TDD band 210 and the FDD band 215 may result in the problems described above (e.g., longer latency, interference, etc.), thereby hindering the ability of the base station 105-a to consistently schedule RACH opportunities on both the TDD band 210 and the FDD band 215.

[0117] To mitigate these issues, the wireless communication system 200 may include techniques for configuring RACH opportunities associated with the TDD band at two uplink time slots in the TDD band 210 and the FDD band 215. For example, for a TDD-FDD CA configuration, the base station 105-a may configure RACH opportunities for the UE 115-a in both the TDD band 210 and the FDD band 215 corresponding to the SSBs of the TDD spectrum. In some cases, the TDD band 210 may configure RACH opportunities in the same CC using the TDD band 210 and / or in different CCs using other frequencies (e.g., the FDD band 215). That is, RACH opportunities scheduled via the TDD band 210 may be scheduled for multiple CCs across different bands and / or carriers (e.g., cross-carrier scheduling). Therefore, when scheduling RACH opportunities via the TDD band 210, the base station 105-a may include carrier information in the RACH opportunity configuration to indicate which CCs are used for the RACH opportunities (e.g., allowing RACH opportunities in the same and / or different carriers)

[0118] The base station 105-a may transmit the RACH configuration (e.g., including carrier information) via an RRC configuration in system information, via a downlink control information (DCI) configuration for a RACH procedure, or a combination thereof. For example, when the UE 115-a evaluates the network before connecting to the network via the base station 105-a, the UE 115-a may monitor and receive system information from the base station 105-a including a RACH timing configuration and a location of SSB transmissions from the base station 105-a. Additionally or alternatively, in some cases, once connected to the base station 105-a, the UE 115-a may receive a DCI configuration including a RACH timing configuration, wherein the DCI configuration may be used for subsequent RACH procedures (such as, for example, for a switching procedure).

[0119] When RACH opportunities are configured / scheduled via TDD band 210, one or more uplink time slots of other CCs that do not use TDD band 210 (e.g., other CCs that use FDD band 215) may not be available for UE 115-a to transmit the first RACH message. For example, one or more uplink time slots of these other CCs may be initially configured for RACH opportunities, but may have other uplink transmissions scheduled during these time slots, or may have unforeseen interference that was not originally seen, making the uplink time slot unavailable for the first RACH message transmission. Therefore, base station 105-a may use RACH interruption avoidance techniques to enable UE 115-a to avoid unavailable uplink time slots based on RACH opportunity configuration that avoids unavailable uplink time slots (e.g., in FDD uplink time slots). In some cases, the RACH interruption avoidance technique may be scheduling-based (e.g., transparent to the UE 115-a), where the base station 105-a indicates to the UE 115-a a RACH opportunity on an available uplink time slot (e.g., schedules the UE 115-a on the available RACH opportunity). For example, the UE 115-a may be unaware of the unavailable time slots and may use the indicated time slots for RACH opportunities based on signaling from the base station 105-a (e.g., the base station 105-a determines the unavailable time slots and ensures that the UE 115-a does not use the unavailable time slots based on only indicating the available time slots).

[0120] Additionally or alternatively, the base station 105-a may transmit an explicit TDM mode notification to the UE 115-a, wherein the UE 115-a subsequently determines an available uplink time slot in other CCs that does not use the TDD frequency band 210 to transmit a first RACH message in a corresponding RACH opportunity. For example, the base station 105-a may configure the TDM mode to the UE 115-a, and when the RACH opportunity and the TDM mode configuration conflict, the UE 115-a may avoid uplink transmissions in uplink time slots of other CCs. In some cases, the base station 105-a may transmit the TDM mode in an RRC message or a DCI configuration. By signaling the TDM mode and enabling the UE 115-a to determine the available uplink time slots, the UE 115-a may more flexibly identify and may use the uplink time slots to transmit the first RACH message, and the base station 105-a may have reduced scheduling complexity.

[0121] In some cases, the base station 105-a may configure a RACH opportunity via the FDD band 215, where the RACH opportunity is configured on an uplink CC using the FDD band 215. When configuring a RACH opportunity on a CC using the FDD band 215, the RACH opportunity may be based on the SSB of a CC using other bands (e.g., the TDD band 210). Thus, the RACH opportunity configured via the FDD band 215 may be self-scheduled (e.g., scheduled on an uplink timeslot of the FDD band 215, where the FDD band 215 is also used to schedule RACH opportunities). Additionally, when the RACH opportunity configuration for the scheduled RACH opportunity is transmitted using the FDD band 215, the RACH opportunity configuration may include corresponding CC information in addition to the time, frequency, and sequence configuration for the RACH opportunity. For example, the CC information may indicate which corresponding CCs of the uplink CC in the FDD band 215 are configured with associated RACH opportunities.

[0122] After transmitting the first RACH message, UE 115-a may expect to receive a RACH response (e.g., a random access response (RAR) message, Msg2 of a four-step RACH procedure, MsgB of a two-step RACH procedure, etc.) from base station 105-a. For example, UE 115-a may expect a RACH response at TDD band 210 or FDD band 215, which is a paired band for an uplink RACH opportunity used by UE 115-a to transmit the first RACH message. Additionally, UE 115-a may identify a RACH response monitoring window for monitoring and receiving RACH responses from base station 105-a. For example, UE 115-a may take into account propagation differences between CCs for the monitoring window. If UE 115-a transmits a first RACH message on a first CC and subsequently receives a RACH response from base station 105-a in a second CC, a delay may occur. For example, if the first CC and the second CC are part of different timing advance groups (TAGs), the timing difference may be such that the UE 115-a cannot ignore the propagation delay when expecting / monitoring the RACH response. Alternatively, if the two CCs are in the same TAG, the UE 115-a may assume that the propagation delta is zero (0).

[0123] Additionally, UE 115-a may determine an initial transmit power for a first RACH message (e.g., Msg1, MsgA, etc.) based on TDD band 210 and FDD band 215. For example, UE 115-a may use measurements (e.g., power measurements, signal quality measurements, reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), etc.) on a corresponding downlink time slot as a reference to an uplink time slot for a RACH opportunity for UE 115-a to transmit the first RACH message. In some cases, a RACH opportunity on an uplink time slot of FDD band 215 may use measurements of a downlink time slot in FDD band 215 instead of a downlink time slot of TDD band 210, even if the corresponding SSB used to configure / schedule the RACH opportunity on the uplink time slot of FDD band 215 is in TDD band 210. Additionally, RACH opportunities on uplink timeslots of TDD frequency band 210 may use measurements of downlink timeslots in TDD frequency band 210. As described above, UE 115-a may transmit a first RACH message on only one CC among multiple RACH opportunities on different CCs.

[0124] In some cases, UE 115-a may retransmit the first RACH message (e.g., RACH preamble). Therefore, UE 115-a may use retransmission interruption avoidance techniques to increase the chances that the retransmission is successfully received and decoded by base station 105-a. In some cases, base station 105-a may indicate the retransmission interruption avoidance techniques in a RACH response message (e.g., RAR, Msg2, MsgB, etc.). For example, when sending a random access radio network temporary identifier (RA-RNTI) to UE 115-a, base station 105-a may add a list of available or prohibited RACH opportunities in a MAC control element (CE). In some cases, RA-RNTI may indicate to UE 115-a that base station 105-a is requesting UE 115-a to retransmit the first RACH message. Therefore, UE 115-a may derive a backoff timer and RACH preamble to be used for retransmission of the first RACH message based on a list of available or prohibited RACH opportunities included in a MAC CE (e.g., together with a RACH response). Additionally or alternatively, UE 115-a may retransmit the first RACH message based on the TDM pattern transmitted by base station 105-a when configuring the RACH opportunity (e.g., as described above). In some cases, UE 115-a may use the TDM pattern received in the RRC signaling based on the TDM pattern having been configured to avoid interruption to UE 115-a.

[0125] Figure 3An example of a process flow 300 for supporting cross-carrier random access configuration according to aspects of the present disclosure is illustrated. In some examples, the process flow 300 can implement aspects of the wireless communication system 100 and / or 200. The process flow 300 can include a base station 105-b and a UE 115-b, which can be respectively as described above with reference to Figure 1 and 2 Examples of corresponding base stations 105 and UEs 115 are described.

[0126] In the following description of process flow 300, operations between base station 105-b and UE 115-b may be communicated in a different order than the exemplary order shown, or operations performed by base station 105-b and UE 115-b may be performed in a different order or at a different time. Certain operations may also be excluded from process flow 300, or other operations may be added to process flow 300. It will be understood that although base station 105-b and UE 115-b are shown as performing several operations of process flow 300, any wireless device may perform the operations shown.

[0127] At 305, the UE 115-b and the base station 105-b may identify a CA configuration for the UE 115-b to communicate with a set of CCs, the CA configuration including a TDD frequency band and at least one FDD frequency band.

[0128] At 310, UE 115-b may receive a RACH opportunity configuration (e.g., from base station 105-b) that schedules a RACH opportunity set for the CC set based on the SSB of the TDD band. For example, the RACH opportunity configuration may include a frequency configuration, a time configuration, a sequence configuration, or a combination thereof for the RACH opportunity set. In some cases, UE 115-b may receive a RACH opportunity configuration in a TDD band, wherein the RACH opportunity set is configured in at least one CC in at least one FDD band, TDD band, or a combination thereof. Additionally, UE 115-b may receive carrier information indicating which CCs are used for the RACH opportunity set. In some cases, UE 115-b may receive the RACH opportunity configuration via an RRC configuration for system information, a DCI configuration for a RACH procedure, or a combination thereof.

[0129] Additionally or alternatively, UE 115-b may receive a RACH opportunity configuration in at least one FDD frequency band, wherein one or more RACH opportunities in a RACH opportunity set are configured in an uplink CC of at least one FDD frequency band, a TDD frequency band, or a combination thereof. In some cases, UE 115-b may determine an uplink CC based on an SSB of a TDD frequency band, an additional SSB block of a CC different from the uplink CC, or a combination thereof. Additionally, UE 115-b may receive CC information indicating which corresponding CCs of the uplink CC are configured with one or more RACH opportunities in at least one FDD frequency band.

[0130] At 315, UE 115-b may measure a signal quality of a downlink CC corresponding to at least one CC used to transmit the first RACH message, and may determine a transmit power for transmitting the first RACH message based on the measured signal quality. In some cases, the downlink CC may be in a TDD frequency band or at least one FDD frequency band (e.g., based on which frequency band the at least one CC used to transmit the first RACH message is in).

[0131] At 320, UE 115-b may transmit a first RACH message for at least one CC during a RACH opportunity in a RACH opportunity set based on a RACH opportunity configuration. In some cases, UE 115-b may receive an indication of an uplink time slot for transmitting the first RACH message. Additionally or alternatively, UE 115-b may receive (e.g., from base station 105-b) a TDM pattern for transmitting the first RACH message, and may determine one or more available RACH opportunities based on the TDM pattern, wherein the first RACH message is transmitted in at least one of the one or more available RACH opportunities. In some cases, the TDM pattern may be received via an RRC message, a DCI configuration, or a combination thereof.

[0132] At 325, UE 115-b may receive a second RACH message based on transmitting the first RACH message. In some cases, UE 115-b may determine a propagation delay based on at least one CC on which the first RACH message is transmitted and an additional CC on which the second RACH message is received, and may monitor a time window based on the propagation delay to look for the second RACH message. In some cases, the propagation delay may be determined based on a first TAG for at least one CC and a second TAG for the additional CC, where the first TAG may be the same as or different from the second TAG. Additionally, the second RACH message may be received on an uplink CC paired with a TDD frequency band or at least one FDD frequency band based on the at least one CC on which the first RACH message is transmitted.

[0133] At 330, UE 115-b may determine that the first RACH message is to be retransmitted, and may transmit the first RACH message a second time based on the determination regarding the retransmission and the received TDM pattern as described above at 320. In some cases, UE 115-b may receive a MAC CE including an RA-RNTI, and may receive a list of available and unavailable RACH opportunities within the MAC CE, and may determine a backoff timer and a retransmission configuration for the first RACH message based on the list of available and unavailable RACH opportunities. Thus, UE 115-b may transmit the first RACH message a second time based at least in part on the backoff timer and the retransmission configuration.

[0134] Figure 4 A block diagram 400 of a device 405 supporting cross-carrier random access configuration according to aspects of the present disclosure is shown. The device 405 may be an example of aspects of the UE 115 as described herein. The device 405 may include a receiver 410, a UE communication manager 415, and a transmitter 420. The device 405 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0135] The receiver 410 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 cross-carrier random access configuration, etc.). The information may be passed to other components of the device 405. The receiver 410 may be a reference Figure 7 Examples of aspects of transceiver 720 are described. Receiver 410 may utilize a single antenna or a collection of antennas.

[0136] The UE communication manager 415 may identify a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band. In some cases, the UE communication manager 415 may receive a random access timing configuration (e.g., a RACH timing configuration) for scheduling a random access timing (e.g., a RACH timing) set for the CC set based on the SSB of the TDD frequency band. Additionally, the UE communication manager 415 may transmit a first random access message (e.g., a first RACH message) for the CC during a random access timing in the random access timing set based on the random access timing configuration. The UE communication manager 415 may be an example of various aspects of the UE communication manager 710 described herein.

[0137] The UE communication manager 415 or its subcomponents may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the UE communication manager 415 or its subcomponents may be performed by 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 designed to perform the functions described in the present disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0138] The UE communication manager 415 or its subcomponents may be physically located in various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the UE communication manager 415 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the UE communication manager 415 or its subcomponents may be combined with one or more other hardware components (including, but not limited to, input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0139] The transmitter 420 may transmit signals generated by other components of the device 405. In some examples, the transmitter 420 may be co-located with the receiver 410 in a transceiver module. For example, the transmitter 420 may be a reference Figure 7 Examples of aspects of transceiver 720 are described. Transmitter 420 may utilize a single antenna or a collection of antennas.

[0140] In some examples, the communication manager 415 may be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 410 and the transmitter 420 may be implemented as analog components (e.g., amplifiers, filters, antennas) coupled to the mobile device modem to enable wireless transmission and reception on one or more frequency bands.

[0141] The communication manager 415 as described herein may be implemented to achieve one or more potential advantages. One implementation may allow the device 405 to perform RACH procedures (e.g., random access procedures) on different frequency bands and CCs based on receiving a single configuration on one of the frequency bands or CCs. Thus, the device 405 may more efficiently establish connections with additional devices on multiple CCs without the increased signaling overhead that may have previously been incurred by configuring each CC or frequency band with a corresponding RACH configuration.

[0142] Figure 5A block diagram 500 of a device 505 supporting cross-carrier random access configuration according to aspects of the present disclosure is shown. The device 505 may be an example of aspects of the device 405 or UE 115 as described herein. The device 505 may include a receiver 510, a UE communication manager 515, and a transmitter 535. The device 505 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0143] The receiver 510 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 cross-carrier random access configuration, etc.). The information may be passed to other components of the device 505. The receiver 510 may be a reference Figure 7 Examples of aspects of transceiver 720 are described. Receiver 510 may utilize a single antenna or a collection of antennas.

[0144] The UE communication manager 515 may be an example of aspects of the UE communication manager 415 as described herein. The UE communication manager 515 may include a CA configuration identifier 520, a RACH opportunity configuration receiver 525, and a first RACH message transmitter 530. The UE communication manager 515 may be an example of aspects of the UE communication manager 710 described herein.

[0145] The CA configuration identifier 520 may identify a CA configuration for communicating with a set of CCs, the CA configuration including a TDD frequency band and at least one FDD frequency band.

[0146] The RACH opportunity configuration receiver 525 may receive a random access opportunity configuration (eg, RACH opportunity configuration) for scheduling a set of random access opportunities (eg, RACH opportunities) for the CC set based on the SSB of the TDD frequency band.

[0147] The first RACH message transmitter 530 may transmit a first random access message (eg, a first RACH message) for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0148] The transmitter 535 can transmit signals generated by other components of the device 505. In some examples, the transmitter 535 can be co-located with the receiver 510 in a transceiver module. For example, the transmitter 535 can be a reference Figure 7 Examples of various aspects of the transceiver 720 are described. The transmitter 535 may utilize a single antenna or a collection of antennas.

[0149] Based on receiving the RACH opportunity configuration for the CC set as described herein, the processor of the UE 115 (e.g., controlling the receiver 510, the transmitter 535, or the like as described in reference Figure 7 The described transceiver 720) can reduce signaling overhead and reduce power consumption by performing RACH procedures across a set of CCs based on a single RACH occasion configuration rather than having a separate configuration for each CC in the set of CCs.

[0150] Figure 6 A block diagram 600 of a UE communication manager 605 supporting cross-carrier random access configuration according to aspects of the present disclosure is shown. The UE communication manager 605 may be an example of aspects of the UE communication manager 415, the UE communication manager 515, or the UE communication manager 710 described herein. The UE communication manager 605 may include a CA configuration identifier 610, a RACH opportunity configuration receiver 615, a first RACH message transmitter 620, a TDD RACH opportunity component 625, an FDD RACH opportunity component 630, a second RACH message receiver 635, a RACH opportunity determination component 640, and a first RACH message retransmitter 645. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0151] The CA configuration identifier 610 may identify a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band.

[0152] The RACH timing configuration receiver 615 may receive a random access timing configuration (e.g., RACH timing configuration) for scheduling a random access timing (e.g., RACH timing) set for the CC set based on the SSB of the TDD frequency band. In some cases, the random access timing configuration may include a frequency configuration for the random access timing set, a time configuration for the random access timing set, a sequence configuration for the random access timing set, or a combination thereof.

[0153] The first RACH message transmitter 620 may transmit a first random access message (e.g., a first RACH message) for a CC during a random access opportunity in a random access opportunity set based on the random access opportunity configuration. In some examples, the first RACH message transmitter 620 may measure a signal quality of a downlink CC corresponding to the CC used to transmit the first random access message, and may determine a transmit power for transmitting the first random access message based on the measured signal quality. In some cases, the downlink CC may be in a TDD frequency band or at least one FDD frequency band.

[0154] The TDD RACH opportunity component 625 may receive a random access opportunity configuration in a TDD frequency band, wherein the random access opportunity set is configured in at least one CC in at least one FDD frequency band, TDD frequency band, or a combination thereof. In some examples, the TDD RACH opportunity component 625 may receive carrier information indicating which CCs are used for the random access opportunity set. Additionally, the TDD RACH opportunity component 625 may receive the random access opportunity configuration via an RRC configuration for system information, a DCI configuration for a random access procedure, or a combination thereof.

[0155] The FDD RACH opportunity component 630 may receive a random access opportunity configuration in at least one FDD frequency band, wherein one or more random access opportunities in a set of random access opportunities are configured in an uplink CC of at least one FDD frequency band, a TDD frequency band, or a combination thereof. In some examples, the FDD RACH opportunity component 630 may determine the uplink CC based on an SSB of a TDD frequency band, an additional SSB of a CC different from the uplink CC, or a combination thereof. Additionally, the FDD RACH opportunity component 630 may receive CC information indicating which corresponding CCs of the uplink CC are configured with one or more random access opportunities in at least one FDD frequency band.

[0156] The second RACH message receiver 635 may receive a second random access message (e.g., a second RACH message RAR, etc.) based on transmitting the first random access message. In some examples, the second RACH message receiver 635 may determine a propagation delay based on the CC on which the first random access message is transmitted and the additional CC on which the second random access message is received, and may monitor the time window based on the propagation delay to find the second random access message. In some cases, the propagation delay may be determined based on a first TAG for the CC and a second TAG for the additional CC, the first TAG being the same as or different from the second TAG. Additionally, the second RACH message may be received on an uplink CC paired with a TDD band or at least one FDD band based on the CC on which the first random access message is transmitted.

[0157] The RACH timing determination component 640 may receive an indication of an uplink time slot for transmitting a first random access message. Additionally or alternatively, the RACH timing determination component 640 may receive a TDM pattern for transmitting the first random access message, and may determine one or more available random access opportunities based on the TDM pattern, wherein the first random access message is transmitted in at least one of the one or more available random access opportunities. In some examples, the RACH timing determination component 640 may determine that the first random access message is to be retransmitted, and may transmit the first random access message a second time based on the determination about the retransmission and the TDM pattern. In some cases, the TDM pattern may be received via an RRC message, a DCI configuration, or a combination thereof.

[0158] The first RACH message retransmitter 645 may receive a MAC CE including an RA-RNTI. In some examples, the first RACH message retransmitter 645 may receive a list of available and unavailable random access opportunities within a MAC control element, and may determine a backoff timer and a retransmission configuration for the first random access message based on the list of available and unavailable random access opportunities. Therefore, the first RACH message retransmitter 645 may transmit the first random access message for a second time based on the backoff timer and the retransmission configuration.

[0159] Figure 7 A diagram of a system 700 including a device 705 supporting cross-carrier random access configurations according to aspects of the present disclosure is shown. The device 705 may be an example of or include a component of a device 405, a device 505, or a UE 115 as described herein. The device 705 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a UE communication manager 710, an I / O controller 715, a transceiver 720, an antenna 725, a memory 730, and a processor 740. These components may be coupled via one or more buses (e.g., a bus 745).

[0160] The UE communication manager 710 may identify a CA configuration for communicating with a CC set, the CA configuration including a TDD frequency band and at least one FDD frequency band. In some cases, the UE communication manager 710 may receive a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on an SSB of the TDD frequency band. Additionally, the UE communication manager 710 may transmit a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0161] I / O controller 715 can manage input and output signals of device 705. I / O controller 715 can also manage peripheral devices that are not integrated into device 705. In some cases, I / O controller 715 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 715 can utilize an operating system, such as Or another known operating system. In other cases, I / O controller 715 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 715 may be implemented as part of a processor. In some cases, a user may interact with device 705 via I / O controller 715 or via hardware components controlled by I / O controller 715.

[0162] The transceiver 720 may communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 720 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 720 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0163] In some cases, a wireless device may include a single antenna 725. However, in some cases, the device may have more than one antenna 725, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0164] The memory 730 may include random access memory (RAM) and read-only memory (ROM). The memory 730 may store computer-readable, computer-executable code 735 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, the memory 730 may include, among other things, a basic I / O system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0165] The processor 740 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a central processing unit (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 740 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 730) so that the device 705 performs various functions (e.g., functions or tasks that support cross-carrier random access configuration).

[0166] The code 735 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 735 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 735 may not be directly executed by the processor 740, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0167] Figure 8 A block diagram 800 of a device 805 supporting cross-carrier random access configuration according to aspects of the present disclosure is shown. The device 805 may be an example of aspects of a base station 105 as described herein. The device 805 may include a receiver 810, a base station communication manager 815, and a transmitter 820. The device 805 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0168] The receiver 810 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 cross-carrier random access configuration, etc.). The information may be passed to other components of the device 805. The receiver 810 may be a reference Fig.11 Examples of various aspects of the transceiver 1120 are described. The receiver 810 may utilize a single antenna or a collection of antennas.

[0169] The base station communication manager 815 may identify a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band. In some cases, the base station communication manager 815 may transmit a random access timing configuration (e.g., RACH timing configuration) of a random access timing (e.g., RACH timing) set scheduled for the CC set based on the SSB of the TDD frequency band. Additionally, the base station communication manager 815 may receive a first random access message (e.g., a first RACH message) for the CC in a random access timing in the random access timing set based on the random access timing configuration. The base station communication manager 815 may be an example of various aspects of the base station communication manager 1110 described herein.

[0170] The base station communication manager 815 or its subcomponents may be implemented in hardware, in 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 base station communication manager 815 or its subcomponents may be performed by a general purpose processor, DSP, ASIC, FPGA or other programmable logic device designed to perform the functions described in the present disclosure, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0171] The base station communication manager 815 or its subcomponents may be physically located at various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the base station communication manager 815 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the base station communication manager 815 or its subcomponents may be combined with one or more other hardware components (including, but not limited to, I / O components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0172] The transmitter 820 may transmit signals generated by other components of the device 805. In some examples, the transmitter 820 may be co-located with the receiver 810 in a transceiver module. For example, the transmitter 820 may be a reference Fig.11 Examples of various aspects of the transceiver 1120 are described. The transmitter 820 may utilize a single antenna or a collection of antennas.

[0173] Fig. 9 A block diagram 900 of a device 905 supporting cross-carrier random access configuration according to aspects of the present disclosure is shown. The device 905 may be an example of aspects of the device 805 or base station 105 as described herein. The device 905 may include a receiver 910, a base station communication manager 915, and a transmitter 935. The device 905 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0174] 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 cross-carrier random access configuration, etc.). The information may be passed to other components of the device 905. The receiver 910 may be a reference Fig.11 Examples of various aspects of the transceiver 1120 are described. The receiver 910 may utilize a single antenna or a collection of antennas.

[0175] The base station communication manager 915 may be an example of aspects of the base station communication manager 815 as described herein. The base station communication manager 915 may include a CA configuration component 920, a RACH opportunity component 925, and a first RACH message receiver 930. The base station communication manager 915 may be an example of aspects of the base station communication manager 1110 described herein.

[0176] CA configuration component 920 can identify a CA configuration for communicating with a UE, the CA configuration comprising a set of CCs in a TDD frequency band and at least one FDD frequency band.

[0177] The RACH opportunity component 925 can transmit a random access opportunity configuration (eg, RACH opportunity configuration) scheduling a set of random access opportunities (eg, RACH opportunities) for the CC set based on the SSB of the TDD frequency band.

[0178] The first RACH message receiver 930 may receive a first random access message (eg, a first RACH message) for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0179] The transmitter 935 can transmit signals generated by other components of the device 905. In some examples, the transmitter 935 can be co-located with the receiver 910 in a transceiver module. For example, the transmitter 935 can be a reference Fig.11 Examples of various aspects of the transceiver 1120 are described. The transmitter 935 may utilize a single antenna or a collection of antennas.

[0180] Fig.10 A block diagram 1000 of a base station communication manager 1005 supporting cross-carrier random access configuration in accordance with aspects of the present disclosure is shown. The base station communication manager 1005 may be an example of aspects of the base station communication manager 815, the base station communication manager 915, or the base station communication manager 1110 described herein. The base station communication manager 1005 may include a CA configuration component 1010, a RACH opportunity component 1015, a first RACH message receiver 1020, a TDD RACH opportunity transmitter 1025, a FDDRACH opportunity transmitter 1030, a second RACH message transmitter 1035, and an uplink timeslot determination component 1040. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0181] CA configuration component 1010 can identify a CA configuration for communicating with a UE, the CA configuration comprising a set of CCs in a TDD frequency band and at least one FDD frequency band.

[0182] The RACH opportunity component 1015 may transmit a random access opportunity configuration (e.g., RACH opportunity configuration) for a random access opportunity (e.g., RACH opportunity) set for the CC set based on the SSB of the TDD frequency band. In some cases, the random access opportunity configuration may include a frequency configuration for the random access opportunity set, a time configuration for the random access opportunity set, a sequence configuration for the random access opportunity set, or a combination thereof.

[0183] The first RACH message receiver 1020 may receive a first random access message (e.g., a first RACH message) for the CC in a random access opportunity in a random access opportunity set based on the random access opportunity configuration. In some examples, the first RACH message receiver 1020 may transmit a MAC CE including an RA-RNTI. Additionally, the first RACH message receiver 1020 may transmit a list of available and unavailable random access opportunities within the MAC CE, and receive the first random access message for a second time based on the list of available and unavailable random access opportunities.

[0184] The TDD RACH opportunity transmitter 1025 may transmit a random access opportunity configuration in a TDD frequency band, wherein the random access opportunity set is configured in at least one CC in at least one FDD frequency band, TDD frequency band, or a combination thereof. In some examples, the TDD RACH opportunity transmitter 1025 may transmit carrier information indicating which CCs are used for the random access opportunity set. Additionally, the TDD RACH opportunity transmitter 1025 may transmit the random access opportunity configuration via an RRC configuration for system information, a DCI configuration for a random access procedure (e.g., a RACH procedure), or a combination thereof.

[0185] The FDD RACH opportunity transmitter 1030 may transmit a random access opportunity configuration in at least one FDD frequency band, wherein one or more random access opportunities in the random access opportunity set are configured in an uplink CC of at least one FDD frequency band, a TDD frequency band, or a combination thereof. In some examples, the FDD RACH opportunity transmitter 1030 may determine the uplink CC based on the SSB of the TDD frequency band, an additional SSB of a CC different from the uplink CC, or a combination thereof. Additionally, the FDD RACH opportunity transmitter 1030 may transmit CC information indicating which corresponding CCs of the uplink CC are configured with one or more random access opportunities in at least one FDD frequency band.

[0186] The second RACH message transmitter 1035 may transmit a second random access message (e.g., a second RACH message, a RAR, etc.) based on receiving the first random access message. In some cases, the second random access message may be transmitted on an uplink CC paired with a TDD frequency band or at least one FDD frequency band based on the CC on which the first random access message is received.

[0187] The uplink time slot determination component 1040 may determine one or more available uplink time slots for the UE to transmit the first random access message, and may transmit an indication of an uplink time slot in the one or more available uplink time slots. Additionally or alternatively, the uplink time slot determination component 1040 may transmit a TDM pattern for the UE to transmit the first random access message, wherein the first random access message may be received based on the TDM pattern. Therefore, the uplink time slot determination component 1040 may receive the first random access message for the second time based on the TDM pattern. In some cases, the TDM pattern may be transmitted via an RRC message, a DCI configuration, or a combination thereof.

[0188] Fig.11 A diagram of a system 1100 including a device 1105 supporting cross-carrier random access configurations according to various aspects of the present disclosure is shown. The device 1105 may be an example of a device 805, a device 905, or a base station 105 as described herein or include components of the above devices. The device 1105 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a base station communication manager 1110, a network communication manager 1115, a transceiver 1120, an antenna 1125, a memory 1130, a processor 1140, and an inter-station communication manager 1145. These components may be coupled via one or more buses (e.g., a bus 1150).

[0189] The base station communication manager 1110 may identify a CA configuration for communicating with a UE, the CA configuration including a CC set in a TDD frequency band and at least one FDD frequency band. In some cases, the base station communication manager 1110 may transmit a random access opportunity configuration for a random access opportunity set for the CC set based on an SSB of the TDD frequency band. Additionally, the base station communication manager 1110 may receive a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration.

[0190] The network communications manager 1115 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1115 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0191] The transceiver 1120 may communicate bidirectionally via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1120 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1120 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0192] In some cases, a wireless device may include a single antenna 1125. However, in some cases, the device may have more than one antenna 1125, which may be capable of transmitting or receiving multiple wireless transmissions concurrently.

[0193] The memory 1130 may include RAM, ROM, or a combination thereof. The memory 1130 may store computer readable code 1135 including instructions that, when executed by a processor (e.g., processor 1140), cause the device to perform various functions described herein. In some cases, the memory 1130 may include, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0194] The processor 1140 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 1140 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into the processor 1140. The processor 1140 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1130) so that the device 1105 performs various functions (e.g., functions or tasks that support cross-carrier random access configuration).

[0195] The inter-site communication manager 1145 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-site communication manager 1145 may coordinate the scheduling of transmissions to UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-site communication manager 1145 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0196] The code 1135 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1135 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 1135 may not be directly executed by the processor 1140, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0197] Fig.121 is a flow chart illustrating a method 1200 for supporting cross-carrier random access configuration according to aspects of the present disclosure. The operations of the method 1200 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1200 may be implemented by a UE 115 or a component thereof as described herein. Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0198] At 1205, the UE may identify a CA configuration for communicating with a set of CCs, the CA configuration comprising a TDD frequency band and at least one FDD frequency band. The operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed as described in reference to Figures 4 to 7 The CA configuration identifier described is performed.

[0199] At 1210, the UE may receive a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1210 may be performed according to the methods described herein. In some examples, various aspects of the operation of 1210 may be performed as described with reference to Figures 4 to 7 The described RACH opportunities configure the receiver to perform.

[0200] At 1215, the UE transmits a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1215 may be performed according to the methods described herein. In some examples, various aspects of the operations of 1215 may be performed as described with reference to Figures 4 to 7 The first RACH message transmitter described is performed.

[0201] Fig.13 1 is a flowchart illustrating a method 1300 for supporting cross-carrier random access configuration according to aspects of the present disclosure. The operations of the method 1300 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1300 may be implemented by a UE 115 or a component thereof as described herein. Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0202] At 1305, the UE may identify a CA configuration for communicating with a set of CCs, the CA configuration comprising a TDD frequency band and at least one FDD frequency band. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be as described in reference to Figures 4 to 7The CA configuration identifier described is performed.

[0203] At 1310, the UE may receive a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1310 may be performed according to the methods described herein. In some examples, various aspects of the operation of 1310 may be performed as described with reference to Figures 4 to 7 The described RACH opportunities configure the receiver to perform.

[0204] At 1315, the UE may receive a random access opportunity configuration in a TDD band, wherein the random access opportunity set is configured in at least one CC in at least one FDD band, TDD band, or a combination thereof. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed as described with reference to Figures 4 to 7 The described TDDRACH timing components are implemented.

[0205] At 1320, the UE transmits a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be as described with reference to Figures 4 to 7 The first RACH message transmitter described is performed.

[0206] Fig.14 1400 for supporting cross-carrier random access configuration according to various aspects of the present disclosure. The operations of the method 1400 may be implemented by the UE 115 or its components as described herein. For example, the operations of the method 1400 may be implemented by the UE 115 or its components as described herein. Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0207] At 1405, the UE may identify a CA configuration for communicating with a set of CCs, the CA configuration comprising a TDD frequency band and at least one FDD frequency band. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed as described in reference to Figures 4 to 7 The CA configuration identifier described is performed.

[0208] At 1410, the UE may receive a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1410 may be performed according to the methods described herein. In some examples, various aspects of the operation of 1410 may be performed as described with reference to Figures 4 to 7 The described RACH opportunities configure the receiver to perform.

[0209] At 1415, the UE may receive the random access opportunity configuration in the at least one FDD frequency band, wherein one or more random access opportunities in the random access opportunity set are configured in an uplink CC of at least one FDD frequency band, a TDD frequency band, or a combination thereof. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed as described with reference to Figures 4 to 7 The described FDD RACH opportunity components are performed.

[0210] At 1420, the UE transmits a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1420 may be performed according to the methods described herein. In some examples, various aspects of the operations of 1420 may be performed as described with reference to Figures 4 to 7 The first RACH message transmitter described is performed.

[0211] Fig.15 1 is a flowchart illustrating a method 1500 for supporting cross-carrier random access configuration according to aspects of the present disclosure. The operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the following functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the following functions.

[0212] At 1505, the UE may identify a CA configuration for communicating with a set of CCs, the CA configuration comprising a TDD frequency band and at least one FDD frequency band. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed as described in reference to Figures 4 to 7 The CA configuration identifier described is performed.

[0213] At 1510, the UE may receive a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1510 may be performed according to the methods described herein. In some examples, various aspects of the operation of 1510 may be performed as described with reference to Figures 4 to 7 The described RACH opportunities configure the receiver to perform.

[0214] At 1515, the UE may receive a TDM pattern for transmitting the first random access message. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed as described with reference to Figures 4 to 7 The described RACH opportunity determination component is performed.

[0215] At 1520, the UE may determine one or more available random access opportunities based on the TDM pattern, wherein the first random access message is transmitted in at least one of the one or more available random access opportunities. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed as described with reference to Figures 4 to 7 The described RACH opportunity determination component is performed.

[0216] At 1525, the UE transmits a first random access message for the CC during a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be as described with reference to Figures 4 to 7 The first RACH message transmitter described is performed.

[0217] Fig.16 1 is a flowchart illustrating a method 1600 for supporting cross-carrier random access configuration according to various aspects of the present disclosure. The operations of the method 1600 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 1600 may be implemented by a base station 105 or components thereof as described herein. Figures 8 to 11 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0218] At 1605, the base station may identify a CA configuration for communicating with the UE, the CA configuration comprising a set of CCs in a TDD frequency band and at least one FDD frequency band. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed as described with reference to Figures 8 to 11 The CA configuration components described are executed.

[0219] At 1610, the base station may transmit a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1610 may be performed according to the method described herein. In some examples, various aspects of the operation of 1610 may be performed as described in reference to Figures 8 to 11 The described RACH opportunity components are performed.

[0220] At 1615, the base station may receive a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1615 may be performed according to the methods described herein. In some examples, various aspects of the operations of 1615 may be performed as described with reference to Figures 8 to 11 The described first RACH message receiver is performed.

[0221] Fig.17 1 is a flowchart illustrating a method 1700 for supporting cross-carrier random access configuration according to various aspects of the present disclosure. The operations of the method 1700 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of the method 1700 may be implemented by a base station 105 or components thereof as described herein. Figures 8 to 11 In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0222] At 1705, the base station may identify a CA configuration for communicating with the UE, the CA configuration comprising a set of CCs in a TDD frequency band and at least one FDD frequency band. 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 as described with reference to Figures 8 to 11 The CA configuration components described are executed.

[0223] At 1710, the base station may transmit a random access opportunity configuration for scheduling a random access opportunity set for the CC set based on the SSB of the TDD frequency band. The operation of 1710 may be performed according to the method described herein. In some examples, various aspects of the operation of 1710 may be performed as described in reference to Figures 8 to 11 The described RACH opportunity components are performed.

[0224] At 1715, the base station may determine one or more available uplink time slots for the UE to transmit the first random access message. The operations of 1715 may be performed according to the methods described herein. In some examples, various aspects of the operations of 1715 may be performed as described with reference to Figures 8 to 11 The described uplink time slot determination component is performed.

[0225] At 1720, the base station may transmit an indication of an uplink time slot in the one or more available uplink time slots. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed as described with reference to Figures 8 to 11 The described uplink time slot determination component is performed.

[0226] At 1725, the base station may receive a first random access message for the CC in a random access opportunity in the random access opportunity set based on the random access opportunity configuration. The operations of 1725 may be performed according to the methods described herein. In some examples, various aspects of the operations of 1725 may be performed as described with reference to Figures 8 to 11 The described first RACH message receiver is performed.

[0227] It should be noted that the methods described herein describe possible implementations, and that the various operations and steps may be rearranged or otherwise modified and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0228] The following provides an overview of various examples of the present invention:

[0229] Example 1: A method for performing wireless communications at a user equipment (UE), comprising: identifying a carrier aggregation configuration for communicating with multiple component carriers, the carrier aggregation configuration comprising a time division duplex band and at least one frequency division duplex band; receiving a random access timing configuration for scheduling multiple random access opportunities for the multiple component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex band; and transmitting a first random access message for the component carrier during a random access opportunity among the multiple random access opportunities based at least in part on the random access timing configuration.

[0230] Example 2: A method as in Example 1, wherein receiving the random access timing configuration comprises: receiving the random access timing configuration in the time division duplex frequency band, wherein the multiple random access timings are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band or a combination thereof.

[0231] Example 3: The method of Example 2, wherein receiving the random access opportunity configuration further comprises: receiving carrier information indicating which component carriers are used for the multiple random access opportunities.

[0232] Example 4: A method as in any one of Examples 2 to 3, wherein receiving the random access timing configuration further comprises: receiving the random access timing configuration via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

[0233] Example 5: A method as in any one of Examples 1 to 4, wherein receiving the random access timing configuration comprises: receiving the random access timing configuration in the at least one frequency division duplex band, wherein one or more random access timings among the multiple random access timings are configured in an uplink component carrier in the at least one frequency division duplex band, the time division duplex band, or a combination thereof.

[0234] Example 6: The method of Example 5 further includes: determining the uplink component carrier at least in part based on a synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

[0235] Example 7: A method as in any one of Examples 5 to 6, wherein receiving the random access opportunity configuration further comprises: receiving component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with one or more random access opportunities in the at least one frequency division duplex band.

[0236] Example 8: A method as in any one of Examples 1 to 7, wherein the random access timing configuration comprises a frequency configuration for the multiple random access timings, a time configuration for the multiple random access timings, a sequence configuration for the multiple random access timings, or a combination thereof.

[0237] Example 9: The method of any one of Examples 1 to 8, further comprising: receiving a second random access message based at least in part on transmitting the first random access message.

[0238] Example 10: The method of Example 9 further includes: determining a propagation delay based at least in part on a component carrier on which the first random access message is transmitted and an additional component carrier on which the second random access message is received; and monitoring a time window to search for a second random access message based at least in part on the propagation delay.

[0239] Example 11: The method of Example 10, wherein the propagation delay is determined based on a first timing advance group for the component carrier and a second timing advance group for the additional component carrier, the first timing advance group being the same as or different from the second timing advance group.

[0240] Example 12: A method as in any of Examples 9 to 11, wherein the second random access message is received on an uplink component carrier paired with the time division duplex band or the at least one frequency division duplex band based at least in part on the component carrier on which the first random access message is transmitted.

[0241] Example 13: A method as in any one of Examples 1 to 12, further comprising: measuring a signal quality of a downlink component carrier corresponding to a component carrier used to transmit a first random access message; and determining a transmit power used to transmit the first random access message based at least in part on the measured signal quality.

[0242] Example 14: The method of Example 13, wherein the downlink component carrier is in the time division duplex frequency band or the at least one frequency division duplex frequency band.

[0243] Example 15: The method of any one of Examples 1 to 14, further comprising: receiving an indication of an uplink timeslot for transmitting the first random access message.

[0244] Example 16: A method as in any one of Examples 1 to 15, further comprising: receiving a time division multiplexing pattern for transmitting a first random access message; and determining one or more available random access opportunities based at least in part on the time division multiplexing pattern, wherein the first random access message is transmitted in at least one of the one or more available random access opportunities.

[0245] Example 17: The method of Example 16 further includes: determining to retransmit the first random access message; and transmitting the first random access message a second time based at least in part on the determination regarding the retransmission and the time division multiplexing pattern.

[0246] Example 18: The method of any one of Examples 16 to 17, wherein the time division multiplexing pattern is received via a radio resource control message, a downlink control information configuration, or a combination thereof.

[0247] Example 19: A method as in any one of Examples 1 to 18, further comprising: receiving a media access control (MAC) control element including a random access radio network temporary identifier; receiving a list of available and unavailable random access opportunities within the MAC control element; determining a backoff timer and a retransmission configuration for a first random access message based at least in part on the list of available and unavailable random access opportunities; and transmitting the first random access message a second time based at least in part on the backoff timer and the retransmission configuration.

[0248] Example 20: A method for performing wireless communications at a base station, comprising: identifying a carrier aggregation configuration for communicating with a user equipment (UE), the carrier aggregation configuration comprising a time division duplex band and multiple component carriers in at least one frequency division duplex band; transmitting a random access timing configuration for scheduling multiple random access timings for the multiple component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex band; and receiving a first random access message for the component carrier in a random access timing among the multiple random access timings based at least in part on the random access timing configuration.

[0249] Example 21: A method as in Example 20, wherein transmitting the random access timing configuration includes: transmitting the random access timing configuration in the time division duplex frequency band, wherein the multiple random access timings are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

[0250] Example 22: The method of Example 21, wherein transmitting the random access opportunity configuration comprises: transmitting carrier information indicating which component carriers are used for the multiple random access opportunities.

[0251] Example 23: A method as in any one of Examples 21 to 22, wherein transmitting the random access timing configuration comprises transmitting the random access timing configuration via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

[0252] Example 24: A method as in any one of Examples 20 to 23, wherein transmitting the random access timing configuration comprises: transmitting the random access timing configuration in the at least one frequency division duplex band, wherein one or more random access timings among the multiple random access timings are configured in an uplink component carrier in the at least one frequency division duplex band, the time division duplex band, or a combination thereof.

[0253] Example 25: The method as described in Example 24 further includes: determining the uplink component carrier at least in part based on a synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

[0254] Example 26: A method as in any one of Examples 24 to 25, wherein transmitting the random access opportunity configuration comprises: transmitting component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with one or more random access opportunities in the at least one frequency division duplex band.

[0255] Example 27: The method of any one of Examples 20 to 26, wherein:

[0256] Example 28: The method of any one of Examples 20 to 27, further comprising: transmitting a second random access message based at least in part on receiving the first random access message.

[0257] Example 29: A method as in Example 28, wherein the random access timing configuration includes a frequency configuration for the multiple random access timings, a time configuration for the multiple random access timings, a sequence configuration for the multiple random access timings, or a combination thereof.

[0258] Example 30: A method as in any one of Examples 20 to 29, further comprising: determining one or more available uplink time slots for the UE to transmit a first random access message; and transmitting an indication of an uplink time slot in the one or more available uplink time slots.

[0259] Example 31: The method of any one of Examples 20 to 30 further comprises: transmitting a time division multiplexing pattern for the UE to transmit a first random access message, wherein the first random access message is received at least in part based on the time division multiplexing pattern.

[0260] Example 32: The method of Example 31 further comprises: receiving the first random access message a second time based at least in part on the time division multiplexing pattern.

[0261] Example 33: A method as in any one of Examples 31 to 32, wherein the time division multiplexing mode is transmitted via a radio resource control message, a downlink control information configuration, or a combination thereof.

[0262] Example 34: A method as in any one of Examples 20 to 33, further comprising: transmitting a media access control (MAC) control element including a random access radio network temporary identifier; transmitting a list of available and unavailable random access opportunities within the MAC control element; and receiving a first random access message for a second time based at least in part on the list of available and unavailable random access opportunities.

[0263] Example 35: An apparatus for wireless communication at a user equipment (UE) includes at least one means for performing the method of any one of Examples 1 to 19.

[0264] Example 36: An apparatus for wireless communication at a user equipment (UE), comprising a processor and a memory coupled to the processor, the processor and the memory configured to perform the method of any one of Examples 1 to 19.

[0265] Example 38: A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to perform the method of any of Examples 1 to 19.

[0266] Example 39: An apparatus for wireless communication at a base station includes at least one means for performing the method of any one of Examples 20 to 34.

[0267] Example 40: An apparatus for wireless communication at a base station, comprising a processor and a memory coupled to the processor, the processor and the memory configured to perform the method of any one of Examples 20 to 34.

[0268] Example 42: A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method of any of Examples 20 to 34.

[0269] The technology described herein can be used in various wireless communication 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. CDMA systems can implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. IS-2000 versions are generally referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is generally referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. TDMA systems can implement radio technologies such as Global System for Mobile Communications (GSM).

[0270] OFDMA systems can implement radio technologies 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 versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from an 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 systems and radio technologies mentioned herein as well as for other systems and radio technologies. Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to applications other than LTE, LTE-A, LTE-A Pro, or NR applications.

[0271] A macro cell generally covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions to a network provider. A small cell may be associated with a lower power base station (compared to a macro cell), and the small cell may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency band as the macro cell. According to various examples, a small cell may include a pico cell, a femto cell, and a micro cell. A pico cell, for example, may cover a smaller geographic area and may allow unrestricted access by UEs with service subscriptions to a network provider. A femto cell may also cover a smaller geographic area (e.g., a residence) and may provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the residence, etc.). 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 more (eg, two, three, four, etc.) cells and may also support communications using one or more CCs.

[0272] The wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, each base station may have similar frame timing, and transmissions from different base stations may be roughly aligned in time. For asynchronous operation, each base station may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0273] The information and signals described herein may be represented using any of a variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0274] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0275] 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 by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0276] Computer-readable medium includes both non-transient computer storage medium and communication medium, and it includes any medium that facilitates computer program to transfer from one place to another place.Non-transient storage medium can be any available medium that can be accessed by general or special-purpose computer.As an example and not limitation, non-transient computer-readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used to carry or store instruction or data structure form of desired program code means and can be accessed by general or special-purpose computer or general or special-purpose processor any other non-transient medium.Similarly, any connection is also properly referred to as computer-readable medium.For example, if software is transmitted from website, server or other remote source using coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then the coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are just included in the definition of medium. Disk and disc as used herein include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0277] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Similarly, as used herein, the phrase "based on" should not be interpreted as referring to a closed set of conditions. For example, an exemplary step described as being based on condition "A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0278] In the accompanying drawings, similar components or features may have the same reference number. In addition, various components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between similar components. If only the first reference number is used in the specification, the description may apply to any of the similar components having the same first reference number regardless of the second reference number, or other subsequent reference numbers.

[0279] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or that fall within the scope of the claims. The term "exemplary" as used herein means "used as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0280] The description herein is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the universal principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: identifying a carrier aggregation configuration for communicating with a plurality of component carriers, the carrier aggregation configuration comprising a time division duplex frequency band and at least one frequency division duplex frequency band; receiving a random access opportunity configuration scheduling a plurality of random access opportunities for the plurality of component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex frequency band; as well as A first random access message for a component carrier is transmitted during a random access opportunity of the plurality of random access opportunities based at least in part on the random access opportunity configuration.

2. The method of claim 1 , wherein receiving the random access opportunity configuration comprises: The random access opportunity configuration is received in the time division duplex frequency band, wherein the plurality of random access opportunities are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

3. The method of claim 2, wherein receiving the random access opportunity configuration further comprises: Carrier information indicating which component carriers are used for the plurality of random access occasions is received.

4. The method of claim 2, wherein receiving the random access opportunity configuration further comprises: The random access opportunity configuration is received via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

5. The method of claim 1 , wherein receiving the random access opportunity configuration comprises: The random access opportunity configuration is received in the at least one frequency division duplex frequency band, wherein one or more random access opportunities of the plurality of random access opportunities are configured in an uplink component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

6. The method of claim 5, further comprising: The uplink component carrier is determined based at least in part on the synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

7. The method of claim 5, wherein receiving the random access opportunity configuration further comprises: Component carrier information is received, the component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with the one or more random access opportunities in the at least one frequency division duplex frequency band.

8. The method of claim 1, wherein the random access opportunity configuration comprises a frequency configuration for the plurality of random access opportunities, a time configuration for the plurality of random access opportunities, a sequence configuration for the plurality of random access opportunities, or a combination thereof.

9. The method of claim 1, further comprising: A second random access message is received based at least in part on transmitting the first random access message.

10. The method of claim 9, further comprising: determining a propagation delay based at least in part on the component carrier on which the first random access message is transmitted and an additional component carrier on which the second random access message is received; and A time window is monitored for the second random access message based at least in part on the propagation delay.

11. The method of claim 10, wherein the propagation delay is determined based on a first timing advance group for the component carrier and a second timing advance group for the additional component carrier, the first timing advance group being the same as or different from the second timing advance group.

12. The method of claim 9, wherein the second random access message is received on an uplink component carrier paired with the time division duplex frequency band or the at least one frequency division duplex frequency band based at least in part on the component carrier on which the first random access message is transmitted.

13. The method of claim 1, further comprising: measuring a signal quality of a downlink component carrier corresponding to the component carrier used to transmit the first random access message; as well as A transmit power for transmitting the first random access message is determined based at least in part on the measured signal quality.

14. The method of claim 13, wherein the downlink component carrier is in the time division duplex frequency band or the at least one frequency division duplex frequency band.

15. The method of claim 1, further comprising: An indication of an uplink timeslot for transmitting the first random access message is received.

16. The method of claim 1, further comprising: receiving a time division multiplexing mode for transmitting the first random access message; as well as One or more available random access opportunities are determined based at least in part on the time division multiplexing pattern, wherein the first random access message is transmitted in at least one of the one or more available random access opportunities.

17. The method of claim 16, further comprising: Determining to retransmit the first random access message; as well as The first random access message is transmitted a second time based at least in part on the determination regarding the retransmission and the time division multiplexing pattern.

18. The method of claim 16, wherein the time division multiplexing mode is received via a radio resource control message, a downlink control information configuration, or a combination thereof.

19. The method of claim 1, further comprising: receiving a medium access control (MAC) control element including a random access radio network temporary identifier; receiving within the MAC control element a list of available and unavailable random access opportunities; determining a backoff timer and a retransmission configuration for the first random access message based at least in part on the list of available and unavailable random access opportunities; and The first random access message is transmitted a second time based at least in part on the backoff timer and the retransmission configuration.

20. A method for wireless communication at a network access node, comprising: identifying a carrier aggregation configuration for communicating with a user equipment (UE), the carrier aggregation configuration comprising a plurality of component carriers in a time division duplex frequency band and at least one frequency division duplex frequency band; transmitting a random access opportunity configuration scheduling a plurality of random access opportunities for the plurality of component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex frequency band; as well as A first random access message for a component carrier is received in a random access opportunity of the plurality of random access opportunities based at least in part on the random access opportunity configuration.

21. The method of claim 20, wherein transmitting the random access opportunity configuration comprises: The random access opportunity configuration is transmitted in the time division duplex frequency band, wherein the plurality of random access opportunities are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

22. The method of claim 21 , wherein transmitting the random access opportunity configuration comprises: Carrier information indicating which component carriers are used for the plurality of random access opportunities is transmitted.

23. The method of claim 21 , wherein transmitting the random access opportunity configuration comprises: The random access opportunity configuration is transmitted via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

24. The method of claim 20, wherein transmitting the random access opportunity configuration comprises: The random access opportunity configuration is transmitted in the at least one frequency division duplex frequency band, wherein one or more random access opportunities of the plurality of random access opportunities are configured in an uplink component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

25. The method of claim 24, further comprising: The uplink component carrier is determined based at least in part on the synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

26. The method of claim 24, wherein transmitting the random access opportunity configuration comprises: Component carrier information is transmitted, the component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with the one or more random access opportunities in the at least one frequency division duplex frequency band.

27. The method of claim 20, further comprising: A second random access message is transmitted based at least in part on receiving the first random access message.

28. The method of claim 20, further comprising: determining one or more available uplink time slots for the UE to transmit the first random access message; as well as An indication of an uplink time slot of the one or more available uplink time slots is transmitted.

29. An apparatus for wireless communication at a user equipment (UE), comprising: processor; as well as a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the apparatus to: identifying a carrier aggregation configuration for communicating with a plurality of component carriers, the carrier aggregation configuration comprising a time division duplex frequency band and at least one frequency division duplex frequency band; receiving a random access opportunity configuration scheduling a plurality of random access opportunities for the plurality of component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex frequency band; as well as A first random access message for a component carrier is transmitted during a random access opportunity of the plurality of random access opportunities based at least in part on the random access opportunity configuration.

30. The apparatus of claim 29, wherein the instruction causing the apparatus to receive the random access opportunity configuration comprises an instruction causing the apparatus to: The random access opportunity configuration is received in the time division duplex frequency band, wherein the plurality of random access opportunities are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

31. The apparatus of claim 30, wherein the instructions causing the apparatus to receive the random access opportunity configuration further comprise instructions causing the apparatus to: Carrier information indicating which component carriers are used for the plurality of random access occasions is received.

32. The apparatus of claim 30, wherein the instructions causing the apparatus to receive the random access opportunity configuration further comprise instructions causing the apparatus to: The random access opportunity configuration is received via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

33. The apparatus of claim 29, wherein the instructions causing the apparatus to receive the random access opportunity configuration comprise instructions causing the apparatus to: The random access opportunity configuration is received in the at least one frequency division duplex frequency band, wherein one or more random access opportunities of the plurality of random access opportunities are configured in an uplink component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

34. The apparatus of claim 33, wherein the instructions further cause the apparatus to: The uplink component carrier is determined based at least in part on the synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

35. The apparatus of claim 33, wherein the instructions causing the apparatus to receive the random access opportunity configuration further comprise instructions causing the apparatus to: Component carrier information is received, the component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with the one or more random access opportunities in the at least one frequency division duplex frequency band.

36. The apparatus of claim 29, wherein the random access opportunity configuration comprises a frequency configuration for the plurality of random access opportunities, a time configuration for the plurality of random access opportunities, a sequence configuration for the plurality of random access opportunities, or a combination thereof.

37. The apparatus of claim 29, wherein the instructions further cause the apparatus to: A second random access message is received based at least in part on transmitting the first random access message.

38. The apparatus of claim 37, wherein the instructions further cause the apparatus to: determining a propagation delay based at least in part on the component carrier on which the first random access message is transmitted and an additional component carrier on which the second random access message is received; and A time window is monitored for the second random access message based at least in part on the propagation delay.

39. The apparatus of claim 38, wherein the propagation delay is determined based on a first timing advance group for the component carrier and a second timing advance group for the additional component carrier, the first timing advance group being the same as or different from the second timing advance group.

40. The apparatus of claim 37, wherein the second random access message is received on an uplink component carrier paired with the time division duplex frequency band or the at least one frequency division duplex frequency band based at least in part on the component carrier on which the first random access message is transmitted.

41. The apparatus of claim 29, wherein the instructions further cause the apparatus to: measuring a signal quality of a downlink component carrier corresponding to the component carrier used to transmit the first random access message; and A transmit power for transmitting the first random access message is determined based at least in part on the measured signal quality.

42. The apparatus of claim 41, wherein the downlink component carrier is in the time division duplex frequency band or the at least one frequency division duplex frequency band.

43. The apparatus of claim 29, wherein the instructions further cause the apparatus to: An indication of an uplink timeslot for transmitting the first random access message is received.

44. The apparatus of claim 29, wherein the instructions further cause the apparatus to: receiving a time division multiplexing mode for transmitting the first random access message; and One or more available random access opportunities are determined based at least in part on the time division multiplexing pattern, wherein the first random access message is transmitted in at least one of the one or more available random access opportunities.

45. The apparatus of claim 44, wherein the instructions further cause the apparatus to: determining to retransmit the first random access message; and The first random access message is transmitted a second time based at least in part on the determination regarding the retransmission and the time division multiplexing pattern.

46. ​​The apparatus of claim 44, wherein the time division multiplexing pattern is received via a radio resource control message, a downlink control information configuration, or a combination thereof.

47. The apparatus of claim 29, wherein the instructions further cause the apparatus to: receiving a medium access control (MAC) control element including a random access radio network temporary identifier; receiving within the MAC control element a list of available and unavailable random access opportunities; determining a backoff timer and a retransmission configuration for the first random access message based at least in part on the list of available and unavailable random access opportunities; and The first random access message is transmitted a second time based at least in part on the backoff timer and the retransmission configuration.

48. An apparatus for wireless communication at a network access node, comprising: processor; as well as a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the apparatus to: identifying a carrier aggregation configuration for communicating with a user equipment (UE), the carrier aggregation configuration comprising a plurality of component carriers in a time division duplex frequency band and at least one frequency division duplex frequency band; transmitting a random access opportunity configuration scheduling a plurality of random access opportunities for the plurality of component carriers based at least in part on a synchronization signal / physical broadcast channel block of the time division duplex frequency band; as well as A first random access message for a component carrier is received in a random access opportunity of the plurality of random access opportunities based at least in part on the random access opportunity configuration.

49. The apparatus of claim 48, wherein the instructions causing the apparatus to transmit the random access opportunity configuration comprise instructions causing the apparatus to: The random access opportunity configuration is transmitted in the time division duplex frequency band, wherein the plurality of random access opportunities are configured in at least one component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

50. The apparatus of claim 49, wherein the instructions causing the apparatus to transmit the random access opportunity configuration comprise instructions causing the apparatus to: Carrier information indicating which component carriers are used for the plurality of random access opportunities is transmitted.

51. The apparatus of claim 49, wherein the instructions causing the apparatus to transmit the random access opportunity configuration comprise instructions causing the apparatus to: The random access opportunity configuration is transmitted via a radio resource control configuration for system information, a downlink control information configuration for a random access procedure, or a combination thereof.

52. The apparatus of claim 48, wherein the instructions causing the apparatus to transmit the random access opportunity configuration comprise instructions causing the apparatus to: The random access opportunity configuration is transmitted in the at least one frequency division duplex frequency band, wherein one or more random access opportunities of the plurality of random access opportunities are configured in an uplink component carrier in the at least one frequency division duplex frequency band, the time division duplex frequency band, or a combination thereof.

53. The apparatus of claim 52, wherein the instructions further cause the apparatus to: The uplink component carrier is determined based at least in part on the synchronization signal / physical broadcast channel block of the time division duplex frequency band, an additional synchronization signal / physical broadcast channel block of a component carrier different from the uplink component carrier, or a combination thereof.

54. The apparatus of claim 52, wherein the instructions causing the apparatus to transmit the random access opportunity configuration comprise instructions causing the apparatus to: Component carrier information is transmitted, the component carrier information indicating which corresponding component carriers of the uplink component carrier are configured with the one or more random access opportunities in the at least one frequency division duplex frequency band.

55. The apparatus of claim 48, wherein the instructions further cause the apparatus to: A second random access message is transmitted based at least in part on receiving the first random access message.

56. The apparatus of claim 48, wherein the instructions further cause the apparatus to: determining one or more available uplink time slots for the UE to transmit the first random access message; and An indication of an uplink time slot of the one or more available uplink time slots is transmitted.

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