PARTIAL RANDOM ACCESS CHANNEL PROCEDURE

Abstract

In an embodiment, the serving BS of the UE may transmit PDCCH communications to the UE. The PDCCH communications trigger a partial RACH procedure, whereby a RACH transmission is performed. In some designs, the RACH transmission is for positioning, and positioning measurements are performed at the serving BS and (optionally) at one or more non-serving BSs. In some designs, measurement data based on the positioning measurements is communicated to a position estimation entity (e.g., an LMF), which performs the UE's positioning estimation.

Description

This Patent Application claims the benefit of U.S. Provisional Application No. 63 / 027,694, entitled “PARTIAL RANDOM ACCESS CHANNEL PROCEDURE”, filed on May 20, 2020, and U.S. Non-Provisional Application No. 17 / 319,416, entitled “PARTIAL RANDOM ACCESS CHANNEL PROCEDURE”, filed on May 13, 2021, both of which are assigned to the assignee hereof and are hereby expressly incorporated by reference herein in their entirety. Invention Engineering Field Aspects of this disclosure generally relate to partial random access channel (RACH) procedures. Background of the Invention Wireless communication systems have evolved through various generations, including first-generation (1G) analog wireless telephone service, second-generation (2G) digital wireless telephone service (including 2.5G interim networks), third-generation (3G) high-speed data, Internet-enabled wireless services, and fourth-generation (4G) services (e.g., LTE or WiMax). There are currently many types of wireless communication systems in use, including mobile and personal communication services (PCS) systems. Examples of well-known cellular systems include the Advanced Analog Mobile Telephone System (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), TDMA variations of the Global System for Mobile Access (GSM), etc. The fifth generation (5G) wireless standard, referred to as New Radio (NR) enables higher data transfer rates, a greater number of connections, and better coverage, among other improvements. According to the Next Generation Mobile Networks Alliance, the 5G standard is designed to deliver data rates of several tens of megabits per second for each of tens of thousands of users, with 1 gigabit per second for dozens of workers on an office floor. Several hundred thousand simultaneous connections must be supported to support large wireless deployments. As a result, the spectral efficiency of 5G mobile communications must be significantly improved compared to the current 4G standard. Furthermore, signaling efficiency must be improved and latency must be substantially reduced compared to the current standard. Brief Description of the Invention The following provides a simplified summary relating to one or more of the aspects disclosed herein. Accordingly, the following summary should not be considered an extensive overview relating to all aspects contemplated, nor should it be considered to identify key or critical elements relating to all aspects contemplated or to delineate the scope relating to any particular aspect. Accordingly, the following summary has the sole purpose of presenting certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below. In an aspect, a method of operating a user equipment (UE) includes receiving a physical downlink control channel (PDCCH) communication; and triggering, in response to the PDCCH communication, a partial random access channel (RACH) procedure. In some aspects, a partial RACH procedure comprises transmitting a RACH signal for positioning. In some aspects, RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one serving non-BS of the UE. In some aspects, the trigger is responsive to the PDCCH communication configuration. In some aspects, the trigger is responsive to at least one PDCCH communication field. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, a partial RACH procedure comprises transmitting a RACH with a first configuration based on the first value, further comprising: receiving another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the trigger is responsive to the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger transmission. SRS for positioning during reception and triggering. In some aspects, a partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the multiple RACH occasions, or a combination thereof. In some aspects, the RACH procedure is based on the time offset indicated through PDCCH communication. In some aspects, the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or the RACH procedure is performed over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In an aspect, a method of operating a service base station (BS) of user equipment (UE) includes transmitting, to the UE, a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receiving, from the UE in response to the PDCCH communication, a RACH transmission. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE. In some aspects, the method includes notifying at least one serving non-BS or location management function (LMF) of a partial RACH procedure to facilitate at least one serving non-BS to perform positioning measurements on the RACH transmission. In some aspects, the method includes sending measurement data based on one or more position measurements to a position estimation entity. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, further comprising: transmitting another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, where the partial RACH procedure consists of receiving a RACH preamble only without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception. In some aspects, a RACH transmission is received on one or more broadcasts corresponding to a plurality of synchronization signal blocks (SSBs), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating a RACH preamble across the plurality of RACH occasions, or a combination thereof. In some aspects, the RACH procedure may be based on a time offset indicated via PDCCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In some aspects, the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure. In an aspect, a method of operating a non-servicing base station (BS) of user equipment (UE) includes receiving a random access channel (RACH) transmission indication from the UE associated with a partial RACH procedure; and receiving a RACH transmission based on the indication. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, the method includes sending measurement data based on one or more position measurements to a position estimation entity. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a method of operating a position estimation entity includes receiving measurement data based on one or more positioning measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UE); and determining an estimate of the UE's position based at least in part on the measurement data. In some aspects, RACH transmission is associated with a partial RACH procedure. In some aspects, the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions for positioning are transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a user equipment (UE) includes memory; a communications interface; and at least one processor communicatively coupled to the memory and the communications interface, the at least one processor configured to: receive, via the communications interface, a physical downlink control channel (PDCCH) communication; and trigger, in response to the PDCCH communication, a partial random access channel (RACH) procedure. In some aspects, a partial RACH procedure comprises transmitting a RACH signal for positioning. In some aspects, RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one serving non-BS of the UE. In some aspects, the trigger is responsive to the PDCCH communication configuration. In some aspects, the trigger is responsive to at least one PDCCH communication field. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, a partial RACH procedure comprises transmitting a RACH with a first configuration based on the first value, further comprising: receiving, via a communication interface, another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the trigger is responsive to the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during reception and triggering. In some aspects, a partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the multiple RACH occasions, or a combination thereof. In some aspects, the RACH procedure is based on the time offset indicated through PDCCH communication. In some aspects, the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or the RACH procedure is performed over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In some aspects, the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure. In an aspect, a base station includes memory; a communications interface; and at least one processor communicatively coupled to the memory and the communications interface, the at least one processor configured to: cause the communications interface to transmit, to the UE, a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receive, via the communications interface, from the UE in response to the PDCCH communication, a RACH transmission. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE. In some aspects, at least one processor is further configured to: notify at least one non-BS presenter or location management function (LMF) of a partial RACH procedure to facilitate at least one non-BS presenter to perform positioning measurements on the RACH transmission. In some aspects, at least one processor is further configured to: cause the communication interface to send measurement data based on one or more positioning measurements to the position estimation entity. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, further comprising: causing the communication interface to transmit another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, where the partial RACH procedure consists of receiving a RACH preamble only without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception. In some aspects, a RACH transmission is received on one or more broadcasts corresponding to a plurality of synchronization signal blocks (SSBs), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating a RACH preamble across the plurality of RACH occasions, or a combination thereof. In some aspects, the RACH procedure may be based on a time offset indicated via PDCCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In an aspect, a base station includes memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor configured to: receive, via the communication interface, a random access channel (RACH) transmission indication from a UE associated with a portion of a RACH procedure; and receive, via the communication interface, a RACH transmission based on the indication. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, at least one processor is further configured to: cause the communication interface to send measurement data based on one or more positioning measurements to the position estimation entity. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a position estimation entity includes a memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor being configured to: receive, via the communication interface, measurement data based on one or more position measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UEs); and determine an estimate of the UE's position based at least in part on the measurement data. In some aspects, RACH transmission is associated with a partial RACH procedure. In some aspects, the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions for positioning are transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, user equipment (UE) includes means for receiving a physical downlink control channel (PDCCH) communication; and means for triggering, in response to the PDCCH communication, a partial random access channel (RACH) procedure. In some aspects, a partial RACH procedure comprises transmitting a RACH signal for positioning. In some aspects, RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one serving non-BS of the UE. In some aspects, the trigger is responsive to the PDCCH communication configuration. In some aspects, the trigger is responsive to at least one PDCCH communication field. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, a partial RACH procedure comprises a RACH transmission with a first configuration based on the first value, further comprising: means for receiving another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the trigger is responsive to the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during reception and triggering. In some aspects, a partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the multiple RACH occasions, or a combination thereof. In some aspects, the RACH procedure is based on the time offset indicated through PDCCH communication. In some aspects, the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or the RACH procedure is performed over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In some aspects, the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure. In an aspect, a base station includes means for transmitting, to a UE, a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and means for receiving, from the UE in response to the PDCCH communication, a RACH transmission. In some aspects, a RACH transmission is for positioning, which further comprises: means for performing one or more positioning measurements on the RACH transmission. In some aspects, RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE. In some aspects, the method includes means for notifying at least one serving non-BS or location management function (LMF) of a partial RACH procedure to facilitate at least one serving non-BS to perform positioning measurements on the RACH transmission. In some aspects, the method includes means for transmitting measurement data based on one or more position measurements to a position estimation entity. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, a RACH transmission configured with a first configuration based on the first value, further comprising: means for transmitting another DCI communication with at least one field comprising the second value, the other DCI communication configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, where the partial RACH procedure consists of receiving a RACH preamble only without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception. In some aspects, a RACH transmission is received on one or more broadcasts corresponding to a plurality of synchronization signal blocks (SSBs), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating a RACH preamble across the plurality of RACH occasions, or a combination thereof. In some aspects, the RACH procedure may be based on a time offset indicated via PDCCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In an aspect, a base station includes means for receiving a random access channel (RACH) transmission indication from a UE associated with a partial RACH procedure; and means for receiving a RACH transmission based on the indication. In some aspects, a RACH transmission is for positioning, which further comprises: means for performing one or more positioning measurements on the RACH transmission. In some aspects, the method includes means for transmitting measurement data based on one or more position measurements to a position estimation entity. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a position estimation entity includes means for receiving measurement data based on one or more positioning measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UE); and means for determining an estimate of the UE's position based at least in part on the measurement data. In some aspects, RACH transmission is associated with a partial RACH procedure. In some aspects, the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions for positioning are transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a computer-readable fixed medium stores computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: receive a physical downlink control channel (PDCCH) communication; and trigger, in response to the PDCCH communication, a partial random access channel (RACH) procedure. In some aspects, a partial RACH procedure comprises transmitting a RACH signal for positioning. In some aspects, RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one serving non-BS of the UE. In some aspects, the trigger is responsive to the PDCCH communication configuration. In some aspects, the trigger is responsive to at least one PDCCH communication field. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, a partial RACH procedure comprises transmitting a RACH with a first configuration based on the first value, further comprising: receiving another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the trigger is responsive to the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during reception and triggering. In some aspects, a partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the multiple RACH occasions, or a combination thereof. In some aspects, the RACH procedure is based on the time offset indicated through PDCCH communication. In some aspects, the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or the RACH procedure is performed over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In some aspects, the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure. In an aspect, a computer-readable fixed medium stores computer-executable instructions that, when executed by a base station, cause the base station to: transmit, to the UE, a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receive, from the UE in response to the PDCCH communication, a RACH transmission. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE. In some aspects, one or more instructions further cause the base station to: notify at least one serving non-BS or location management function (LMF) of a partial RACH procedure to facilitate at least one serving non-BS to perform a position measurement on the RACH transmission. In some aspects, one or more further instructions cause the base station to: send measurement data based on the one or more position measurements to the position estimation entity. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication. In some aspects, at least one field comprises a radio network temporary identifier (RNTI), or at least one field is part of a downlink control information (DCI) communication, or a combination thereof. In some aspects, at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, further comprising: transmitting another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. In some aspects, the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, where the partial RACH procedure consists of receiving a RACH preamble only without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception. In some aspects, a RACH transmission is received on one or more broadcasts corresponding to a plurality of synchronization signal blocks (SSBs), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating a RACH preamble across the plurality of RACH occasions, or a combination thereof. In some aspects, the RACH procedure may be based on a time offset indicated via PDCCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In some aspects, the partial RACH procedure is an uplink portion of a joint uplink and downlink positioning procedure, and the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. In an aspect, a computer-readable fixed medium stores computer-executable instructions that, when executed by a base station, cause the base station to: receive a random access channel (RACH) transmission indication from a UE associated with a partial RACH procedure; and receive a RACH transmission based on the indication. In some aspects, the RACH transmission is for positioning, which further comprises: performing one or more positioning measurements on the RACH transmission. In some aspects, one or more further instructions cause the base station to: send measurement data based on the one or more position measurements to the position estimation entity. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions are received over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. In an aspect, a computer-readable fixed medium stores computer-executable instructions that, when executed by a position estimation entity, cause the position estimation entity to: receive measurement data based on one or more position measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UE); and determine an estimate of the UE's position based at least in part on the measurement data. In some aspects, RACH transmission is associated with a partial RACH procedure. In some aspects, the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS. In some aspects, a partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure consists of transmitting only a RACH preamble without a RACH response to the RACH preamble. In some aspects, a partial RACH procedure is a partial 2-Step RACH procedure, and the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. In some aspects, RACH transmissions for positioning are transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or RACH transmissions are received over shared spectrum shared by a plurality of RATs. Other objects and advantages related to the aspects disclosed herein will be apparent to those skilled in the art from the accompanying drawings and detailed descriptions. Short Description of Image The accompanying drawings are provided to assist in the description of various aspects of the present disclosure and are provided solely for illustration of these aspects and not as a limitation thereof. Figure 1 depicts an exemplary wireless communication system, according to various aspects. Figures 2A and 2B illustrate examples of wireless network structures, according to various aspects. Figure 3 is a block diagram depicting an exemplary UE, according to various aspects. Figures 4A to 4D are diagrams illustrating examples of frame structures and channels within the frame structure, according to aspects of the present disclosure. Figure 5 illustrates a DCI-triggered SRS-P procedure in accordance with aspects of the present disclosure. Figure 6 illustrates a 4-Step Physical Random Access Channel (PRACH) procedure in accordance with an embodiment of the disclosure. Figure 7 illustrates a 2-Step PRACH procedure in accordance with an embodiment of the disclosure. Figure 8 illustrates an example of a wireless communication process, according to aspects of the present disclosure. Figure 9 illustrates an exemplary wireless communication process, according to aspects of the present disclosure. Figure 10 illustrates an example of a wireless communication process, according to aspects of the present disclosure. Figure 11 illustrates an exemplary wireless communication process, according to aspects of the present disclosure. Figure 12 illustrates an example of the application of a process in accordance with the aspects of this disclosure. Figure 13 illustrates an example of the application of a process in accordance with the aspects of this disclosure. Complete Description of the Invention Aspects of this disclosure are provided in the following description and related drawings, which refer to various examples provided for illustrative purposes. Alternative aspects may be designed without departing from the scope of this disclosure. In addition, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the details of the relevant disclosure. The words "exemplary" and / or "example" are used herein to mean "example," "sample," or "illustrative." Any aspect described herein as "exemplary" and / or "example" should not be construed as being preferable or advantageous to any other aspect. Likewise, the term "aspect" of the disclosure does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed. Those skilled in the art will appreciate that the information and signals described below can be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the description below can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or combinations thereof, depending in part on the specific application, in part on the desired design, in part on the appropriate technology, etc. Furthermore, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that the various actions described herein may be performed by a particular circuit (e.g., an application-specific integrated circuit (ASIC)), by program instructions executed by one or more processors, or by a combination of both. In addition, the sequences of actions described herein may be considered to be embodied entirely in any form of computer-readable fixed storage medium that has stored therein a set of appropriate computer instructions that, upon execution, will cause or instruct the associated processors of the device to perform the functions described herein. Thus, the various aspects of the present disclosure may be embodied in a number of different forms, all of which have been considered to be within the scope of the claimed subject matter.Additionally, for each aspect described herein, the corresponding form of each such aspect may be described herein as, for example, the logic configured to perform the described actions. As used herein, the terms user equipment (UE) and base station are not intended to be specific or limited to a particular Radio Access Technology (RAT), unless otherwise stated. In general, a UE can be any wireless communications device (e.g., mobile phone, router, tablet computer, laptop computer, tracking device, wearable device (e.g., smart watch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle (e.g., car, motorcycle, bicycle, etc.), Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communications network. The UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with the Radio Access Network (RAN).As used herein, the term UE may be referred to interchangeably as an access terminal or AT, client device, “wireless device,” subscriber device, subscriber terminal, a subscriber station, user terminal or UT, mobile terminal, mobile station, or variations thereof. Generally, a UE can communicate with the core network via the RAN, and via the core network, the UE can be connected to external networks such as the Internet and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for a UE, such as a wired access network, a wireless local area network (WLAN) network (e.g., based on IEEE 802.11, etc.) and so on. A base station can operate according to one of several RATs in communication with the UE depending on the network in which it is deployed, and can be referred to as an access point (AP), network node, NodeB, evolved NodeB (eNB), New Radio (NR) Node B (also referred to as gNB or gNodeB), etc. In addition, in some systems, the base station may provide pure edge node signaling functions while in other systems it may provide additional control and / or network management functions. A communication link through which the UE can send signals to the base station is called an uplink (UL) channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). A communication link through which the base station can send signals to the UE is called a downlink (DL) or forward link channel (e.g., pager channel, control channel, broadcast channel, forward traffic channel, etc.).As used herein, the term traffic channel (TCH) may refer to either a UL / reverse or DL / forward traffic channel. The term base station may refer to a single physical transmission point or multiple physical transmission points that may or may not be co-located. For example, where the term base station refers to a single physical transmission point, the physical transmission point may be the base station antenna corresponding to the base station cell. Where the term base station refers to multiple co-located physical transmission points, the physical transmission point may be the antenna array (e.g., as in a multiple-input-multiple-output (MIMO) system or where the base station uses transmitting) of the base station. Where the term base station refers to multiple non-co-located physical transmission points, the physical transmission point may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote transmitter connected to a serving base station).Alternatively, the non-located physical transmission points can be a serving base station that receives measurement reports from the UE and a neighboring base station whose reference RF signal is measured by the UE. An RF signal consists of electromagnetic waves of a specific frequency that transport information through space between a transmitter and a receiver. As used herein, a transmitter can transmit a single RF signal or multiple RF signals to a receiver. However, a receiver can receive multiple RF signals corresponding to each transmitted RF signal due to the propagation characteristics of RF signals over a multipath channel. The same RF signal transmitted on different paths between the transmitter and the receiver can be referred to as a multipath RF signal. According to various aspects, Figure 1 illustrates an exemplary wireless communication system 100. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include a plurality of base stations 102 and a plurality of UEs 104. The base stations 102 may include macro cell base stations (high-power mobile base stations) and / or small cell base stations (low-power mobile base stations). In an aspect, the macro cell base stations may include eNBs wherein the wireless communication system 100 corresponds to an LTE network, or gNBs wherein the wireless communication system 100 corresponds to a 5G network, or a combination of both, and the small cell base stations may include femto cells, pico cells, micro cells, etc. The base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or a next generation core (NGC)) via a backhaul link 122, and via the core network 170 to one or more server locations 172. In addition to other functions, the base stations 102 may perform functions related to one or more of user data transfer, radio channel encoding and decoding, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multi-channel broadcast multimedia services (MBMS), subscriber and equipment tracking, RAN information management (RIM), pager, positioning, and alert messaging.The base stations 102 may communicate with each other directly or indirectly (e.g., via EPC / NGC) via a backhaul link 134, which may be wired or wireless. The base station 102 may communicate wirelessly with the UE 104. Each base station 102 may provide communications coverage for its respective geographic coverage area 110. In an aspect, one or more cells may be supported by the base station 102 in each coverage area 110. A cell is a logical communications entity used for communications with the base station (e.g., over multiple frequency sources, referred to as carrier frequencies, component carriers, operators, bands, or the like), and may be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID)) to distinguish cells operating over the same or different carrier frequencies. In some cases, different cells may be configured according to different types of protocols (e.g., machine-type communications (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs.In some cases, the term cell may also refer to the geographic coverage area of ​​a base station (e.g., sector), to the extent that carrier frequencies can be detected and used for communication within some portion of the geographic coverage area 110. While neighboring macro cell base stations 102's geographic coverage areas 110 may partially overlap (e.g., in handover regions), some geographic coverage areas 110 may substantially overlap with larger geographic coverage areas 110. For example, a small cell base station 102' may have a coverage area 110' that substantially overlaps with the coverage areas 110 of one or more macro cell base stations 102. A network that includes both small cell base stations and macro cells may be known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may provide services to a limited group known as a closed subscriber group (CSG). The communication link 120 between the base station 102 and the UE 104 may include a UL transmission (also referred to as a backlink) from the UE 104 to the base station 102 and / or a downlink (DL) transmission (also referred to as a forward link) from the base station 102 to the UE 104. The communication link 120 may utilize MIMO antenna technology, including spatial multiplexing, transmitting, and / or transmitting diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL than to UL). The wireless communication system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with a WLAN station (STA) 152 over a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in an unlicensed frequency spectrum, the WLAN STAs 152 and / or WLAN AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether the channel is available. The small cell base station 102' may operate in licensed and / or unlicensed frequency spectrum. When operating in unlicensed frequency spectrum, the small cell base station 102' may utilize LTE or 5G technology and utilize the same unlicensed 5 GHz frequency spectrum as utilized by the WLAN AP 150. The small cell base station 102', utilizing LTE / 5G in unlicensed frequency spectrum, may enhance the coverage and / or increase the capacity of the access network. LTE in unlicensed spectrum may be referred to as LTE-unlicensed (LTE-U), License Assisted Access (LAA), or MulteFire. The wireless communication system 100 may further include a millimeter wave (mmW) transmitter 180 that may operate at mmW and / or near mmW frequencies in communication with the UE 182. Extremely high frequency (EHF) is a portion of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as millimeter waves. Near mmW may extend to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter waves. Communications using the mmW / near mmW radio frequency bands have high path loss and relatively short range. The mmW transmitter 180 and the UE 182 may use transmitting (transmitting and / or receiving) over the mmW communication link 184 to compensate for the extremely high path loss and short range.Furthermore, it will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Therefore, it will be appreciated that the above illustrations are merely examples and should not be construed to limit the various aspects disclosed herein. Transmitting is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omni-directional). With transmitting, the network node determines where a particular target device (e.g., a UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal to the receiving device. To change the direction of the RF signal during transmission, the network node can control the relative phase and amplitude of the RF signal at each of one or more transmitters broadcasting the RF signal.For example, network nodes can use an array of antennas (referred to as a phased array or antenna array) that creates a beam of RF waves that can be steered to point in different directions, without actually moving the antennas. Specifically, the RF current from the transmitter is fed to each antenna with the correct phase relationship so that the radio waves from the separate antennas are combined to enhance radiation in the desired direction, while canceling out to suppress radiation in undesired directions. Beams may be quasi-collocated, meaning that they appear to the receiver (e.g., UE) to have the same parameters, regardless of where the transmitting antennas of the network nodes themselves are physically located. In NR, there are four types of quasi-collocation (QCL) relationships. Specifically, a QCL relationship of a given type means that certain parameters about a second reference RF signal on the second beam can be derived from information about the source reference RF signal on the source beam. Thus, if the source reference RF signal is a QCL Type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and spread delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is a Type B QCL, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is a Type C QCL, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is a Type D QCL, the receiver can use the source reference RF signal to estimate the spatial reception parameters of a second reference RF signal transmitted on the same channel. In receiving a transmission, the receiver uses the receiver beam to amplify the RF signal detected on a particular channel. For example, the receiver may increase the gain setting and / or adjust the phase setting of the antenna array in a particular direction to amplify (i.e., to increase the gain level) the RF signal received from that direction. Thus, when a receiver is said to transmit in a particular direction, it means that the beam gain in that direction is high relative to the beam gain along other directions, or that the beam gain in that direction is the highest compared to the beam gain in that direction of all other received beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of the RF signal received from that direction. Receiver beams may be spatially related. Spatial relatedness means that parameters for a beam for a second reference signal can be derived from information about a receiver beam for a first reference signal. For example, a UE may use a specific receive beam to receive a downlink reference signal (e.g., a synchronization signal block (SSB)) from a base station. The UE may then form a beam to transmit an uplink reference signal (e.g., a beeping reference signal (SRS)) to that base station based on the parameters of the receive beam. Note that a “downlink beam” can be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station forms a downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. If a UE forms a downlink beam, however, it is a receive beam to receive the downlink reference signal. Similarly, an “uplink beam” can be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station forms an uplink beam, it is an uplink receive beam, and if a UE forms an uplink beam, it is an uplink transmit beam. In 5G, the frequency spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into several frequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system, such as 5G, one of the carrier frequencies is referred to as the primary carrier or anchor carrier or primary serving cell or PCell,” and the remaining carrier frequencies are referred to as secondary carriers or secondary serving cells or SCells. In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) used by the UE 104 / 182 and the cell in which the UE 104 / 182 performs the initial radio source control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all UE common and dedicated control channels.A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that can be configured after the RRC connection is established between the UE 104 and the anchor carrier and that can be used to provide additional radio resources. The secondary carrier may only contain necessary signaling information and signals, for example, UE-specific ones, as the primary uplink and downlink carriers are typically UE-specific. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same applies to uplink primary carriers. The network can change the primary carrier of a UE 104 / 182 at any time. This is done, for example, to balance the load on different carriers.Since the serving cell (whether PCell or SCell) corresponds to a carrier / component carrier frequency on which multiple base stations communicate, the terms cell, serving cell, component carrier, carrier frequency,” and the like can be used interchangeably. For example, still referring to Figure 1, one of the frequencies used by the macro cell base station 102 may be an anchor carrier (or PCell) and the other frequency used by the macro cell base station 102 and / or the mmW base station 180 may be a secondary carrier (“SCell”). Simultaneous transmission and / or reception of multiple carriers allows the UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, two combined 20 MHz carriers in a multi-carrier system will theoretically result in a twofold increase in data rate (i.e., 40 MHz), compared to that achieved by a single 20 MHz carrier. The wireless communication system 100 may further include one or more UEs, such as UE 190, that connect indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the example of Figure 1, UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which UE 190 can indirectly obtain cellular connectivity) and a D2D P2P link 194 with WLAN STA 152 connected to WLAN AP 150 (through which UE 190 can indirectly obtain WLAN-based Internet connectivity). For example, the D2D P2P links 192 and 194 may be supported with well-known D2D RATs, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on. The wireless communication system 100 may further include a UE 164 that may communicate with a macro cell base station 102 over a communication link 120 and / or a mmW base station 180 over a mmW communication link 184. For example, the macro cell base station 102 may support a PCell and one or more SCells for the UE 164 and the mmW base station 180 may support one or more SCells for the UE 164. In an aspect, the UE 164 may include a positioning component 166 that enables the UE 164 to perform the UE operations described herein. Note that although only one UE in Figure 1 is illustrated as having a fully staggered SRS component 166, any of the UEs in Figure 1 may be configured to perform the UE operations described herein. According to various aspects, Figure 2A illustrates an example of a wireless network structure 200. For example, the NGC 210 (also referred to as 5GC) can be functionally viewed as control plane functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions 212, (e.g., UE gateway function, access to data network, IP routing, etc.) operating cooperatively to form a core network. The user plane interface (NG-U) 213 and the control plane interface (NG-C) 215 connect the gNB 222 to the NGC 210 and specifically to the control plane function 214 and the user plane function 212. In additional configurations, the eNB 224 can also be connected to the NGC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. Furthermore, the eNB 224 can directly communicate with the gNB 222 via the backhaul connection 223.In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicate with UE 204 (e.g., one of the UEs depicted in Figure 1). Other optional aspects may include a location server 230, which may communicate with NGC 210 to provide location assistance for UE 204. Location servers 230 may be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively each corresponding to a single server. Location servers 230 may be configured to support one or more location services for UEs 204 that may connect to location servers 230 via the core network, NGC 210, and / or via the Internet (not illustrated).Further, the location server (230) may be integrated into the core network components, or alternatively may be external to the core network. According to various aspects, Figure 2B illustrates another example of a wireless network structure 250. For example, the NGC 260 (also referred to as 5GC) can be functionally viewed as a control plane function, provided by the access and mobility management function (AMF) / user plane function (UPF) 264, and a user plane function, provided by the session management function (SMF) 262, which operate cooperatively to form a core network (i.e., the NGC 260). The user plane interface 263 and the control plane interface 265 connect the eNB 224 to the NGC 260 and specifically to the SMF 262 and AMF / UPF 264, respectively. In additional configurations, the gNB 222 may also be connected to the NGC 260 via the control plane interface 265 to the AMF / UPF 264 and the user plane interface 263 to the SMF 262. Furthermore, the eNB 224 may communicate directly with the gNB 222 via the backhaul connection 223, with or without the gNB's direct connectivity to the NGC 260.In some configurations, the New RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 can communicate with UE 204 (e.g., one of the UEs depicted in Figure 1). The base station of the New RAN 220 communicates with the AMF side of the AMF / UPF 264 via the N2 interface and the UPF side of the AMF / UPF 264 via the N3 interface. The AMF functions include registration management, connection management, range management, mobility management, authorized interception, transport for session management (SM) messages between UE 204 and SMF 262, transparent proxy service for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between UE 204 and short message service function (SMSF) (not shown), and security anchor function (SEAF). The AMF also interacts with the authentication server function (AUSF) (not shown) and UE 204, and receives intermediate keys generated as a result of the UE 204 authentication process. In the case of authentication based on UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF retrieves security material from the AUSF. The AMF functions also include security context management (SCM). The SCM receives keys from the SEAF that are used to derive access network-specific keys.The AMF functionality also includes location service management for setup services, transport for location service messages between the UE 204 and the location management function (LMF) 270, as well as between the New RAN 220 and the LMF 270, expanded packet system (EPS) operator identifier allocation for interworking with the EPS, and notification of UE 204 mobility events. In addition, the AMF also supports functionality for non-3GPP access networks. UPF functions include acting as an anchor point for intra- / inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point from the interconnect to the data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., UL / DL level enforcement, reflective QoS tagging in the DL), UL traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet tagging in the UL and DL, DL packet buffering and DL data notification triggering, and delivery and forwarding from one or more “end markers” to the source RAN node. The functions of the SMF 262 include session management, UE Internet Protocol (IP) address allocation and management, user plane function selection and control, traffic steering configuration in the UPF to direct traffic to the appropriate destination, control of part of policy enforcement and QoS, and downlink data notification. The interface through which the SMF 262 communicates with the AMF side of the AMF / UPF 264 is referred to as the N11 interface. Other optional aspects may include an LMF 270, which may communicate with an NGC 260 to provide location assistance to the UE 204. The LMF 270 may be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively each corresponding to a single server. The LMF 270 may be configured to support one or more location services for the UE 204 that may connect to the LMF 270 via the core network, the NGC 260, and / or via the Internet (not illustrated). Figure 3 illustrates some sample components (represented by appropriate blocks) that may be incorporated into UE 302 (which may correspond to any of the UEs described herein), base station 304 (which may correspond to any of the base stations described herein), and network entity 306 (which may correspond to or embody any of the network functions described herein, including location server 230 and LMF 270) to support file transmission operations as taught herein. It will be appreciated that these components may be implemented in various types of equipment in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other equipment in a communications system. For example, other equipment in a system may include components similar to those described to provide similar functionality.Also, a given piece of equipment may contain one or more components. For example, a piece of equipment may include multiple transceiver components that enable the equipment to operate on multiple carriers and / or communicate over different technologies. The UE 302 and the base station 304 each include at least one wireless communication device (represented by communication devices 308 and 314 (and communication device 320 if the device 304 is a relay)) for communicating with other nodes via at least one designated RAT. For example, communication devices 308 and 314 may communicate with each other via a wireless communication link 360, which may correspond to the communication link 120 in FIG. 1. Each communication device 308 includes at least one transmitter (represented by transmitter 310) for transmitting and decoding signals (e.g., messages, indications, information, and so on) and at least one receiver (represented by receiver 312) for receiving and decoding signals (e.g., messages, indications, information, pilots, and so on).Similarly, each communication device 314 includes at least one transmitter (represented by transmitter 316) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by receiver 318) for receiving signals (e.g., messages, indications, information, and so on). If the base station 304 is a relay station, each communication device 320 may include at least one transmitter (represented by transmitter 322) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by receiver 324) for receiving signals (e.g., messages, indications, information, and so on). The transmitter and receiver may comprise an integrated device (e.g., realized as a transmitter circuit and a receiver circuit of a single communication device, generally referred to as a transceiver) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be realized in other ways in other implementations. A wireless communication device (e.g., one of several wireless communication devices) of the base station 304 may also comprise a network listening module (NLM) or the like for performing various measurements. Network entity 306 (and base station 304 if not a relay station) includes at least one communication device (represented by communication device 326 and, optionally, 320) for communicating with other nodes. For example, communication device 326 may comprise a network interface configured to communicate with one or more network entities via a wired or wireless backhaul 370 (which may correspond to a backhaul link 122 in FIG. 1). In some aspects, communication device 326 may be implemented as a transceiver configured to support wired or wireless signal communication, and transmitter 328 and receiver 330 may be integrated units. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information. Thus, in the example of FIG. 3, communication device 326 is shown to comprise transmitter 328 and receiver 330.Alternatively, transmitter 328 and receiver 330 may be separate devices within communication device 326. Similarly, if base station 304 is not a relay station, communication device 320 may comprise a network interface configured to communicate with one or more network entities 306 via wired or wireless-based backhaul 370. As with communication device 326, communication device 320 is shown as comprising transmitter 322 and receiver 324. Apparatus 302, 304, and 306 also include other components that may be used in conjunction with file transmission operations as disclosed herein. UE 302 includes a processing system 332 to provide functionality related to, for example, UE operations as described herein and to provide other processing functionality. Base station 304 includes a processing system 334 to provide functionality related to, for example, base station operations as described herein and to provide other processing functionality. Network entity 306 includes a processing system 336 to provide functionality related to, for example, network function operations as described herein and to provide other processing functionality.Apparatus 302, 304, and 306 include memory components 338, 340, and 342 (e.g., each includes a memory device), respectively, for maintaining information (e.g., information indicating reserved resources, thresholds, parameters, and so on). In addition, UE 302 includes a user interface 350 for providing indications (e.g., audible and / or visual indications) to the user and / or for receiving user input (e.g., when the user moves a sensing device such as a keypad, touchscreen, microphone, and so on). Although not shown, apparatus 304 and 306 may also include a user interface. Referring to the processing system 334 in more detail, in the downlink, IP packets from the network entity 306 may be provided to the processing system 334. The processing system 334 may implement functionality for the radio resource control (RRC) layer, data packet convergence protocol (PDCP) layer, radio link control (RLC) layer, and media access control (MAC) layer. The processing system 334 may provide RRC layer functionality related to broadcasting system information (e.g., master information block (MIB), system information block (SIB)), RRC connection control (e.g., RRC connection insertion, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality related to header compression / decompression, security (encoding, decoding, integrity protection, integrity verification), and handover support functions; RLC layer functionality related to upper-layer packet data unit (PDU) transfer, error correction via ARQ, merging, segmenting, and reassembling RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to mapping between logical channels and transport channels, reporting of scheduling information, error correction, priority handling, and logical channel prioritization. Transmitter 316 and receiver 318 may implement Layer-1 functionality related to various signal processing functions. Layer-1, which includes the physical layer (PHY), may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping to physical channels, modulation / demodulation of the physical channels, and MIMO antenna processing. Transmitter 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be divided into parallel streams.Each stream can then be mapped to an orthogonal frequency division multiplex (OFDM) sub-carrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined together using the Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a stream of time-domain OFDM symbols. The OFDM streams are spatially pre-encoded to produce multiple spatial streams. Channel estimates from the channel estimator can be used to determine coding and modulation schemes, as well as for spatial processing. Channel estimates can be derived from reference signals and / or channel condition feedback transmitted by UE 302. Each spatial stream can then be assigned to one or more different antennas. Transmitter 316 can modulate the RF carrier with the respective spatial stream for transmission. At UE 302, receiver 312 receives the signals through its respective antenna. Receiver 312 recovers the modulated information to the RF carrier and provides the information to processing system 332. Transmitter 310 and receiver 312 implement Layer-1 functionality associated with various signal processing functions. Receiver 312 may perform spatial processing on the information to recover each spatial stream destined for UE 302. If multiple spatial streams are destined for UE 302, they may be combined by receiver 312 into a single OFDM symbol stream. Receiver 312 then converts the OFDM symbol stream from the time domain to the frequency domain using fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each sub-carrier of the OFDM signal.The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 304. These soft decisions may be based on channel estimates computed by a channel estimator. The soft decisions are then decoded and separated to recover the data and control signals originally transmitted by the base station 304 on the physical channel. The data and control signals are then provided to the processing system 332, which implements Layer-3 and Layer-2 functionality. In UL, the 332 processing system provides demultiplexing between transport and logical channels, packet reassembly, parsing, header decompression, and control signal processing to recover IP packets from the core network. The 332 processing system is also responsible for error detection. Similar to the functionality described with respect to DL transmission by base station 304, the processing system 332 provides RRC layer functionality related to acquisition of system information (e.g., MIB, SIB), RRC connections, and measurement reporting; PDCP layer functionality related to header compression / decompression, and security (encoding, decoding, integrity protection, integrity verification); RLC layer functionality related to upper layer PDU transfer, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to mapping between logical channels and transport channels, multiplexing MAC SDUs to transport blocks (TBs), demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and prioritization of logical channels. The channel estimates obtained by the channel estimator from the reference or feedback signals transmitted by the base station 304 can be used by the transmitter 310 to select appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter 310 can be fed to different antennas. The transmitter 310 can modulate the RF carrier with the respective spatial streams for transmission. The UL transmission is processed at the base station 304 in a manner similar to that described with respect to the receiver function at the UE 302. The receiver 318 receives the signal through its respective antenna. The receiver 318 recovers the modulated information to the RF carrier and provides the information to the processing system 334. In the UL, processing system 334 provides demultiplexing between transport and logical channels, packet reassembly, parsing, header decompression, and control signal processing to recover IP packets from UE 302. IP packets from processing system 334 can be forwarded to the core network. Processing system 334 is also responsible for error detection. In an aspect, the apparatus 302, 304 and 306 may each include RACH components 344, 348 and positioning components 349. It will be appreciated that the functionality of the various components 344, 348 and 349 may differ based on the device in which they are implemented. The RACH components 344, 348 and positioning components 349 may be hardware circuitry that is part of or coupled to the processing systems 332, 334 and 336, respectively, which, when executed, cause the apparatus 302, 304 and 306 to perform the functionality described herein. Alternatively, the RACH components 344, 348 and positioning component 349 may be memory modules stored in memory components 338, 340, and 342, respectively, which, when executed by the processing systems 332, 334, and 336, cause the devices 302, 304, and 306 to perform the functions described herein. For convenience, devices 302, 304, and / or 306 are shown in Figure 3 including various components that may be configured according to the various examples described herein. However, it will be appreciated that the illustrated blocks may have different functions in different designs. The various components of the equipment 302, 304, and 306 may communicate with each other via data buses 352, 354, and 356, respectively. The components of Figure 3 may be implemented in various ways. In some implementations, the components of Figure 3 may be implemented in one or more circuits such as, for example, one or more processors and / or one or more ASICs (which may include one or more processors). Here, each circuit may utilize and / or incorporate at least one memory component to store information or executable code used by the circuit to provide this functionality. For example, some or all of the functions represented by blocks 308, 332, 338, 344, and 350 may be implemented by the processor and memory components of UE 302 (e.g., by appropriate code execution and / or by configuration of the processor components).Similarly, some or all of the functions represented by blocks 314, 320, 334, 340, and 348 may be implemented by the processor and memory components of the base station 304 (e.g., by appropriate code execution and / or by configuration of the processor components). Also, some or all of the functions represented by blocks 326, 336, 342, and 349 may be implemented by the processor and memory components of the network entity 306 (e.g., by appropriate code execution and / or by appropriate configuration of the processor components). For simplicity, various operations, actions, and / or functions are described herein as being performed by the UE, by the base station, by the positioning entity, etc. However, as will be appreciated, such operations, actions, and / or functions may actually be performed by any particular component or combination of components of the UE, the base station, the positioning entity, etc., such as processing systems 332, 334, 336, communication devices 308, 314, 326, RACH components 344, 348 and positioning components 349, etc. Various frame structures can be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). Figure 4A is a diagram 400 illustrating an example of a downlink frame structure, according to aspects of the present disclosure. Figure 4B is a diagram 430 illustrating an example of a channel in a downlink frame structure, according to aspects of the present disclosure. Figure 4C is a diagram 450 illustrating an example of an uplink frame structure, according to aspects of the present disclosure. Figure 4D is a diagram 480 illustrating an example of a channel in an uplink frame structure, according to aspects of the present disclosure. Other wireless communication technologies may have different frame structures and / or different channels. LTE, and in some cases NR, uses OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. Unlike LTE, however, NR has the option of using OFDM on the uplink as well. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also often referred to as tones, bins, etc. Each subcarrier can be modulated with data. Generally, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) may depend on the system bandwidth. For example, the subcarrier spacing might be 15 kilohertz (kHz) and the minimum resource allocation (resource block) might be 12 subcarriers (or 180 kHz). As a result, the nominal FFT size may be equal to 128, 256, 512, 1024, or 2048 for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively.The system bandwidth can also be partitioned into subbands. For example, a subband might cover 1.08 MHz (i.e., 6 source blocks), and there might be 1, 2, 4, 8, or 16 subbands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively. LTE supports a single numerology (subcarrier spacing (SCS), symbol length, etc.). In contrast, NR can support multiple numerologies (μ), for example, subcarrier spacings of 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz (μ=2), 120 kHz (μ=3), and 240 kHz (μ=4) or larger may be available. In each subcarrier spacing, there are 14 symbols per slot. For 15 kHz SCS (μ=0), there is one slot per subframe, 10 slots per frame, the slot duration is 1 millisecond (ms), the symbol duration is 66.7 microseconds (μs), and the maximum nominal system bandwidth (in MHz) with a 4K FFT size is 50. For 30 kHz SCS (μ=1), there are two slots per subframe, 20 slots per frame, the slot duration is 0.5 ms, the symbol duration is 33.3 s, and the maximum nominal system bandwidth (in MHz) with a 4K FFT size is 100. For 60 kHz SCS (μ=2), there are four slots per subframe, 40 slots per frame, the slot duration is 0.25 ms, the symbol duration is 16.7 s, and the maximum nominal system bandwidth (in MHz) with a 4K FFT size is 200.For 120 kHz SCS (μ=3), there are eight slots per subframe, 80 slots per frame, the slot duration is 0.125 ms, the symbol duration is 8.33 s, and the maximum nominal system bandwidth (in MHz) with a 4K FFT size is 400. For 240 kHz SCS (μ=4), there are 16 slots per subframe, 160 slots per frame, the slot duration is 0.0625 ms, the symbol duration is 4.17 s, and the maximum nominal system bandwidth (in MHz) with a 4K FFT size is 800. In the examples of Figures 4A to 4D, 15 kHz numerology is used. Thus, in the time domain, a 10 ms frame is divided into 10 equally sized subframes of 1 ms each, and each subframe covers one time slot. In Figures 4A to 4D, time is represented horizontally (on the X-axis) with time increasing from left to right, while frequency is represented vertically (on the Y-axis) with frequency increasing (or decreasing) from bottom to top. A source grid can be used to represent a time slot, each time slot including one or more concurrent time resource blocks (RBs) (also referred to as physical RBs (PRBs)) in the frequency domain. The source grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one sub-carrier in the frequency domain. In the numerology of Figures 4A to 4D, for a normal cyclic prefix, an RB may contain 12 consecutive sub-carriers in the frequency domain and seven consecutive symbols in the time domain, for a total of 84 REs. For an extended cyclic prefix, an RB may contain 12 consecutive sub-carriers in the frequency domain and six consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme. Some REs carry a downlink (pilot) reference signal (DL-RS). DL-RS can include PRS, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB, etc. Figure 4A illustrates an example of an RE location carrying a PRS (labeled “R). The set of source elements (REs) used for PRS transmission is called a PRS source. The set of source elements can span multiple PRBs in the frequency domain and 'N' (like 1 or more) consecutive symbols in a slot in the time domain. In a given OFDM symbol in the time domain, the PRS source occupies consecutive PRBs in the frequency domain. PRS source transmission in a particular PRB has a specific comb size (also referred to as comb density). The comb size 'N' represents the sub-carrier spacing (or frequency / tone spacing) in each PRS source configuration symbol. Specifically, for a comb size 'N,' PRS is transmitted in every Nth sub-carrier of the PRB symbol. For example, for comb-4, for each PRS source configuration symbol, REs corresponding to every fourth sub-carrier (such as sub-carriers 0, 4, 8) are used to transmit PRS from the PRS source. Currently, comb sizes of comb-2, comb-4, comb-6, and comb-12 are supported for DL-PRS. Figure 4A illustrates an example of a PRS source configuration for a comb-6 (which includes six symbols). That is, the shaded RE location (labeled “R”) indicates the comb-6 PRS source configuration. Currently, DL-PRS sources can span 2, 4, 6, or 12 consecutive symbols in a slot with a full frequency domain staggered pattern. DL-PRS sources can be configured at any higher layer configured downlink or flexible symbols (FL) of the slot. There can be a constant energy per resource element (EPRE) for all REs of a given DL-PRS source. The following are the frequency offsets from symbol to symbol for comb sizes of 2, 4, 6, and 12 over 2, 4, 6, and 12 symbols. 2-symbol comb2: {0, 1}; 4-symbol comb-2: {0, 1, 0, 1}; 6-symbol comb-2: {0, 1, 0, 1, 0, 1}; 12-symbol comb-2: {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}; 4-symbol comb-4: {0, 2, 1, 3}; 12-symbol comb-4: {0, 2, 1, 3, 0, 2, 1, 3, 0, 2, 1, 3}; 6-symbol comb: {0, 3, 1, 4, 2, 5}; 12-symbol comb-6: {0, 3, 1, 4, 2, 5, 0, 3, 1, 4, 2, 5}; and 12 comb-12 symbols: {0, 6, 3, 9, 1, 7, 4, 10, 2, 8, 5, 11}. A PRS source set is a set of PRS sources used for PRS signal transmission, where each PRS source has a PRS source ID. In addition, PRS sources in a PRS source set are associated with the same TRP. A PRS source set is identified by a PRS source set ID and is associated with a specific TRP (identified by the TRP ID). In addition, PRS sources in a PRS source set have the same periodicity, the same muting pattern configuration, and the same repetition factor (such as “PRS-ResourceRepetitionFactor”) across slots. The periodicity is the time from the first repetition of the first PRS source of the first PRS instance to the first repetition of the same first PRS source of the next PRS instance. The periodicity may have a selected length of 2Λμ*{4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320, 640, 1280, 2560, 5120, 10240}, with = 0, 1, 2, 3. The repetition factor may have any length chosen from the slots {1, 2, 4, 6, 8, 16, 32}. A PRS source ID in a PRS source pool is associated with a single beam (or beam ID) transmitted from a single TRP (where a TRP may transmit one or more beams). This means that each PRS source in a PRS source pool may transmit on a different beam, and thus, a PRS source, or simply a source, may also be referred to as a beam. Note that this has no implications on whether the TRP and the beam the PRS is transmitting are known to the UE. A PRS instance or PRS opportunity is one instance of a periodically recurring time window (such as a group of one or more consecutive slots) during which a PRS is expected to be transmitted. A PRS event may also be referred to as a PRS positioning event, PRS positioning instance, positioning event, positioning instance, positioning repetition, or simply event, instance, or repetition. A positioning frequency layer (also referred to simply as a frequency layer) is a collection of one or more PRS source sets in one or more TRPs that have the same values ​​for certain parameters. Specifically, a collection of PRS source sets has the same subcarrier spacing and cyclic prefix (CP) type (meaning all numerologies supported for PDSCH are also supported for PRS), the same Point A, the same downlink PRS bandwidth value, the same starting PRB (and center frequency), and the same comb size. The Point A parameter takes the value of the ARFCN-ValueNR parameter (where ARFCN stands for absolute radio frequency channel number) and is an identifier / code that specifies the physical radio channel pair used for transmission and reception. The downlink PRS bandwidth may have a granularity of four PRBs, with a minimum of 24 PRBs and a maximum of 272 PRBs.Currently, up to four frequency layers are defined, and up to two sets of PRS sources can be configured per TRP per frequency layer. The concept of frequency layers is somewhat similar to the concept of component carriers and bandwidth shares (BWP), but differs in that component carriers and BWP are used by a single base station (or macro cell base station and small cell base station) to transmit data channels, while frequency layers are used by multiple (usually three or more) base stations to transmit PRS. The UE can indicate the number of frequency layers it can support when transmitting its positioning capabilities to the network, such as during an LTE positioning protocol (LPP) session. For example, the UE can indicate whether it can support one or four positioning frequency layers. Figure 4B illustrates an example of multiple channels in a downlink slot of a radio frame. In NR, the channel bandwidth, or system bandwidth, is divided into multiple BWPs. BWPs are contiguous sets of PRBs selected from a contiguous subset of common RBs for a given numerology on a given carrier. Typically, a maximum of four BWPs can be defined in the downlink and uplink. This means that a UE can be configured with up to four BWPs on the downlink and up to four BWPs on the uplink. Only one BWP (either uplink or downlink) can be active at any given time, meaning the UE can only receive or transmit more than one BWP at a time. In the downlink, the bandwidth of each BWP must be equal to or greater than the SSB bandwidth, but may or may not contain SSB. Referring to Figure 4B, the primary synchronization signal (PSS) is used by the UE to determine the subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the PCI. Based on the PCI, the UE can determine the DL-RS location mentioned above. The physical broadcast channel (PBCH), which carries the MIB, can be logically grouped with the PSS and SSS to form an SSB (also referred to as SS / PBCH). The MIB provides a number of RBs in the downlink system bandwidth and system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted over the PBCH, such as system information blocks (SIBs), and pager messages. The physical downlink control channel (PDCCH) carries downlink control information (DCI) in one or more control channel elements (CCEs), each CCE includes one or more RE group bundles (REGs) (which can span multiple symbols in the time domain), each REG bundle includes one or more REGs, each REG corresponds to 12 source elements (one source block) in the frequency domain and one OFDM symbol in the time domain. The set of physical sources used to carry the PDCCH / DCI is referred to in NR as the control source set (CORESET). In NR, the PDCCH is limited to a single CORESET and is transmitted with its own DMRS. This allows UE-specific broadcasting of the PDCCH. In the example of Figure 4B, there is one CORESET per BWP, and the CORESET spans three symbols (although it may only be one or two symbols) in the time domain. Unlike the LTE control channel, which occupies the entire system bandwidth, in NR, the PDCCH channel is localized to a specific region in the frequency domain (i.e., the CORESET). Thus, the frequency components of the PDCCH shown in Figure 4B are illustrated as less than one BWP in the frequency domain. Note that although the illustrated CORESETs are contiguous in the frequency domain, they do not have to be. Furthermore, CORESETs can span less than three symbols in the time domain. The DCI in the PDCCH carries information about uplink resource allocation (persistent and non-persistent) and a description of the downlink data transmitted to the UE, referred to as uplink and downlink grants, respectively. More specifically, the DCI indicates the resources scheduled for the downlink data channel (e.g., PDSCH) and the uplink data channel (e.g., PUSCH). Multiple (e.g., up to eight) DCIs can be configured in the PDCCH, and these DCIs can have one of several formats. For example, there are different DCI formats for uplink scheduling, for downlink scheduling, for uplink transmission power control (TPC), etc. The PDCCH can be carried by 1, 2, 4, 8, or 16 CCEs to accommodate different DCI payload sizes or coding rates. As illustrated in Figure 4C, some REs (labeled R) carry DMRS for channel estimation at the receiver (e.g., base station, other UEs, etc.). An additional UE may transmit an SRS, for example, the last symbol of a slot. The SRS may have a comb structure, and the UE may transmit an SRS on any of the combs. In the example of Figure 4C, the illustrated SRS is comb-2 over a single symbol. The SRS can be used by the base station to obtain channel state information (CSI) for each UE. The CSI describes how RF signals propagate from the UE to the base station and represents the combined effects of scattering, fading, and power decay with distance. The system uses SRS for resource scheduling, link adaptation, massive MIMO, beam management, etc. Currently, SRS sources can span 1, 2, 4, 8, or 12 consecutive symbols in slots of combo size combo-2, combo-4, or combo-8. The following are the symbol-to-symbol frequency offsets for the currently supported SRS combo patterns. 1-symbol combo-2: {0}; 2-symbol combo-2: {0, 1}; 4-symbol combo-2: {0, 1, 0, 1}; 4-symbol combo-4: {0, 2, 1, 3}; 8-symbol comb-4: {0, 2, 1, 3, 0, 2, 1, 3}; 12-symbol comb4: {0, 2, 1, 3, 0, 2, 1, 3, 0, 2, 1, 3}; 4-symbol comb-8: {0, 4, 2, 6}; 8-symbol comb-8: {0, 4, 2, 6, 1, 5, 3, 7}; and 12-symbol comb-8: {0, 4, 2, 6, 1, 5, 3, 7, 0, 4, 2, 6}. The set of source elements used for SRS transmission is called an SRS resource, and can be identified by the SRS-ResourceId parameter. The set of source elements can span multiple PRBs in the frequency domain and N (i.e., one or more) consecutive symbols in slots in the time domain. In a given OFDM symbol, SRS resources occupy consecutive PRBs. An SRS resource set is a set of SRS sources used for SRS signal transmission, and is identified by the SRS resource set ID (SRS-ResourceSetId). Generally, the UE transmits an SRS to enable a receiving base station (either a serving base station or a neighboring base station) to measure the channel quality between the UE and the base station. However, the SRS can also be specifically configured as an uplink positioning reference signal for uplink-based positioning procedures, such as uplink time difference of arrival (ULTDOA), round-trip time (RTT), uplink angle of arrival (UL-AoA), etc. As used herein, the term SRS may refer to an SRS configured for channel quality measurement or an SRS configured for positioning purposes. The former may be referred to herein as SRS-for-communications and / or the latter may be referred to as SRS-for-positioning when necessary to distinguish between the two types of SRS.Several enhancements over the previous SRS definition have been proposed for SRS-for-positioning (also referred to as UL-PRS), such as a new staggered pattern in SRS resources (except for single symbol / comb-2), a new comb type for SRS, a new sequence for SRS, a higher number of SRS source sets per component carrier, and a higher number of SRS resources per component carrier. In addition, the SpatialRelationInfo and PathLossReference parameters must be configured based on the downlink or SSB reference signal from neighboring TRPs. Furthermore, a single SRS source can be transmitted outside the active BWP, and a single SRS source can span multiple component carriers. Also, SRS can be configured in the RRC-connected state and only transmitted within the active BWP. Furthermore, there may be no frequency hopping, no repetition factor, a single antenna port, and new lengths for SRS (e.g., 8 and 12 symbols).There may also be open-loop power control instead of closed-loop power control, and comb-8 (i.e., SRS transmitted every eighth subcarrier within the same symbol) may be used. Finally, the UE may transmit over the same beam from multiple SRS resources for UL-AoA. All of these are additional features to the current SRS framework, configured via higher-layer RRC signaling (and potentially triggered or activated via a MAC control element (CE) or DCI). Figure 4D illustrates examples of various channels in an uplink slot of a frame, according to aspects of the present disclosure. A random access channel (RACH), also referred to as a physical random access channel (PRACH), may be in one or more slots in the frame based on the PRACH configuration. The PRACH may include six consecutive RB pairs in a slot. The PRACH enables the UE to perform initial system access and achieve uplink synchronization. The physical uplink control channel (PUCCH) may be located at the edge of the uplink system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, CSI reports, channel quality indicators (CQI), precode matrix indicators (PMI), rating indicators (RI), and HARQ ACK / NACK feedback. The physical uplink shared channel (PUSCH) carries data, and may also be used to carry buffer status reports (BSRs), power headroom reports (PHRs), and / or UCIs. Note that the terms positioning reference signal and PRS generally refer to the specific reference signal used for positioning in NR and LTE systems. However, as used herein, the terms positioning reference signal and PRS may also refer to any type of reference signal that can be used for positioning, such as but not limited to, PRS as defined in LTE and NR, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB, SRS, UL-PRS, etc. In addition, the terms positioning reference signal and PRS may refer to either a downlink or an uplink positioning reference signal, unless otherwise indicated by the context. If it is necessary to further differentiate the types of PRS, a downlink positioning reference signal may be referred to as a DL-PRS, and an uplink positioning reference signal (e.g., SRS-for-positioning, PTRS) may be referred to as a UL-PRS.Additionally, for signals that can be transmitted in both uplink and downlink (e.g., DMRS, PTRS), the signal can be prefixed with UL or DL ​​to distinguish the direction. For example, UL-DMRS can be distinguished from DL-DMRS. The SRS is an uplink-only signal transmitted by the UE to help the base station obtain channel state information (CSI) for each user. Channel state information describes how RF signals propagate from the UE to the base station and represents the combined effects of scattering, fading, and power decay over distance. The system uses the SRS for resource scheduling, link adaptation, massive MIMO, beam management, and more. Several enhancements to the previous SRS definition have been proposed for SRS for positioning (SRS-P), such as a new staggered pattern in SRS resources, a new comb type for SRS, a new sequence for SRS, a higher number of SRS resource sets per component operator, and a higher number of SRS resources per component operator. In addition, the parameters SpatialRelationInfo and PathLossReference must be configured based on the DL RS of neighboring TRPs. Furthermore, a single SRS resource can be transmitted outside the active bandwidth portion (BWP), and a single SRS resource can span multiple component carriers. Finally, the UE can transmit over the same beam multiple SRS resources for UL-AoA. All of these are additional features to the current SRS framework, configured via higher-layer RRC signaling (and potentially triggered or activated via MAC control elements (CEs) or downlink control information (DCIs)). As mentioned above, the sounding reference signal (SRS) in NR is a UE-specifically configured reference signal transmitted by the UE that is used for the purpose of sounding the uplink radio channel. Similar to CSI-RS, such sounding provides varying degrees of knowledge about the characteristics of the radio channel. On the one hand, SRS can be used at the gNB simply to obtain signal strength measurements, for example, for UL beam management purposes. On the other hand, SRS can be used at the gNB to obtain detailed amplitude and phase estimates as a function of frequency, time, and space. In NR, channel sounding with SRS supports a more diverse set of use cases compared to LTE (e.g., downlink CSI acquisition for mutually exclusive (downlink MIMO) gNB transmissions; uplink CSI acquisition for link adaptation and codebook / non-codebook-based precoding for uplink MIMO, uplink beam management, etc.). SRS can be configured using various options. The time / frequency mapping of the SRS source is determined by the following characteristics. • NsymbSRS time duration- The time duration of the SRS resource can be 1, 2, or 4 consecutive OFDM symbols in a slot, unlike LTE which only allows one OFDM symbol per slot. • Starting symbol location l0 - The starting symbol of the SRS resource can be placed anywhere within the last 6 OFDM symbols of the slot as long as the resource does not cross the end boundary of the slot. • Repetition factor R - For SRS sources configured with frequency hopping, repetition allows the same set of sub-carriers to be sounded in R consecutive OFDM symbols before the next hop occurs (as used here, a hop refers specifically to the hop frequency). For example, the values ​​of R are 1, 2, 4 where R <NsymbSRS. • KTC transmission comb spacing and kTC comb offset - An SRS resource can occupy a source element (RE) of a frequency domain comb structure, where the comb spacing is 2 or 4 REs as in LTE. Such a structure allows frequency domain multiplexing of different SRS resources from the same or different users on different combs, where the different combs are offset from each other by an integer number of REs. The comb offset is defined with respect to the PRB boundaries, and can take values ​​in the range 0,1,.., KTC-1 REs. Thus, for a comb spacing KTC=2, there are 2 different combs available for multiplexing if needed, and for a comb spacing KTC=4, there are 4 different combs available. • Periodicity and slot offset for periodic / semi-persistent SRS cases. • Send bandwidth in bandwidth sections. For low latency positioning, the gNB can trigger the UL SRS-P over DCI (e.g., the transmitted SRS-P may include repeats or beam sweeps to enable multiple gNBs to receive the SRS-P). Alternatively, the gNB may send information about aperiodic PRS transmissions to the UE (e.g., this configuration may include information about PRSs from multiple gNBs to enable the UE to perform timing calculations for positioning (UE-based) or for reporting (UE-assisted). Figure 5 illustrates a DCI-triggered SRS-P procedure 500 in accordance with aspects of the present disclosure. At 502, an active SRS configuration is established between a serving BS 304 and a UE 302. At 504, the serving BS 304 utilizes the active SRS configuration established at 502 to transmit a DCI comprising a PDCCH configured to trigger an SRS-P. At 506, the UE 302 transmits an SRS-P in response to the PDCCH. The serving BS 304 and one or more non-serving BSs 304 measure the SRS-P respectively at 508510. In some scenarios, it may be the case that the UE does not have an active SRS configuration that can be used by the gNB to immediately trigger an SRS transmission. Embodiments of the disclosure are thus directed to a Random Access Channel (RACH) transmission for positioning (e.g., a RACH preamble transmission), which in some designs may be part of a partial RACH procedure corresponding to a limited or truncated version of the 'normal' RACH procedure. Such embodiments may provide various technical advantages, such as obtaining a rough positioning estimate for the UE with lower latency (e.g., particularly for scenarios where an active SRS configuration is not set for the UE). Below, a complete RACH (or PRACH) procedure is described with respect to Figures 6-7, followed by a discussion of the partial RACH procedure in accordance with various aspects of the disclosure. Figure 6 illustrates a 4-Step Physical Random Access Channel (PRACH) procedure 600 in accordance with an embodiment of the disclosure. The 4-Step PRACH procedure 600 is an initial access procedure whereby a UE (e.g., UE 302) can initiate communication with a BS (e.g., BS 304). Referring to Figure 6, at 602, Message 1 (Msg-1) of the 4-Step PRACH procedure 600 is transmitted by UE 302 to BS 304. Message-1 of 602 can be characterized here as a PRACH preamble (or more generally as a RACH preamble). In the example, Msg-1 of 602 can be implemented a Zadoff-Chu sequence that indicates a random access attempt and allows BS 304 to perform channel estimation between BS 304 and UE 302. Referring to Figure 6, at 604, Message 2 (Message-2”) of the 4-Step PRACH procedure 600 is transmitted by the BS 304 to the UE 302. Message-2 of 604 can be characterized here as a random access response (RAR). For example, in response to a detected PRACH preamble (or Msg-1) at 602, the BS 304 may transmit Msg-2 of 604 on the downlink (DL) shared channel (SCH) consisting of any combination of: • The detected PRACH preamble index (or Msg1) of 602, • The uplink time correction for UE 302, • The scheduling grant indicating which source UE 302 should use for the transmission of Message 3 (Msg-3”) of the 4-Step PRACH procedure 600, and • The Temporary Cell Radio Network Identifier (TC-RNTI) used for further communication between UE 302 and BS 304. In the example, Msg-2 of 604 can be scheduled on the SL SCH and indicated on the downlink Physical Control Channel (PDCCH) using the identity (e.g., Random Access RNTI (RA-RNTI)) indicated by the time and frequency source on which the PRACH preamble (or Msg-1) of 602 is transmitted. Referring to Figure 6, at 606, a Message 3 (Msg-3”) consisting of at least the UE identifier (ID) of UE 302 is transmitted by UE 302 to BS 304. In some designs, the Msg-3 is transmitted over the Physical Uplink Shared Channel (PUSCH) and may be referred to as Msg-3 PUSCH. In the example, the Msg-3 transmitted at 606 may be transmitted over the source UL SCH indicated by Msg-2 of 604. In some designs, device scrambling is used for the transmission of the Msg-3 at 606 (e.g., scrambling based on the TC-RNTI assigned via Msg2 of 604). In some designs, if UE 302 is in the radio source control (RRC)-connected state with a C-RNTI assigned to it, the C-RNTI may be used as the UE-ID in the Msg-3 at 606. In some designs, if UE 302 is not in the RRC-Connected state, the identifier core network devices such as the 40-bit Serving Temporary Mobile Subscriber Identity (S-TMSI) can be used as the UE-ID in Msg-3 in 606. Referring to Figure 6, at 608, another Msg-3 is optionally transmitted as an acknowledgment (ACK) of the hybrid auto-repeat request (HARQ) to Msg-2 of 604. In some designs, Msg-3 is transmitted over the PUCCH and may be referred to as Msg-3 PUCCH. In some designs, whether or not Msg-3 PUCCH is transmitted at 608 may be configured via RRC signaling or via one or more information elements (IEs) in the system information block (SIB). Referring to Figure 6, at 610, Message 4 (Msg-4”) of the 4-Step PRACH procedure 600 is transmitted by BS 304 to UE 302. In some designs, Msg-4 of 608 comprises a downlink message for contention resolution as there are multiple possible contentions associated with the transmission of Msg-3 at 606-608. For example, if multiple UEs transmit the same Msg-1 (602) at the same time, then multiple UEs may react to the same Msg-2 (604) resulting in a collision. In some designs, if UE 302 already has a C-RNTI assigned, contention resolution can be handled by addressing UE 302 on the PDCCH using the C-RNTI.In some designs, if UE 302 does not have a valid C-RNTI (e.g., UE 302 was RRC-Idle before 602), Msg-4 contention resolution can be handled by addressing UE 302 on the PDCCH using TC-RNTI, with UE 302 comparing (i) the UE-ID received in the PDSCH scheduled by the PDCCH of Msg-4 with (ii) the UE-ID transmitted in the Msg-3 PUSCH at 606, to determine the 4-Step PRACH procedure 600 succeeds if a match is observed, after which the C-RNTI is confirmed as the C-RNTI. At 612, UE 302 and BS 304 may optionally exchange user data. Figure 7 illustrates a 2-Step PRACH procedure 700 in accordance with an embodiment of the disclosure. Similar to the 4-Step PRACH procedure 600, the 2-Step PRACH procedure 700 is an initial access procedure whereby a UE (e.g., UE 302) can initiate communication with a BS (e.g., BS 304). However, in the 2-Step PRACH procedure 700, Msg-1 and Msg-3 (PUSCH) are transmitted to BS 304 before any response from BS 304 is transmitted as 'Msg-A', and BS 304 sends 'Msg-B' (e.g., consisting of Msg-2 and Msg-4) back to UE 302. Referring to Figure 7, at 702, UE 302 transmits Msg-A (e.g., PRACH preamble and associated UE ID information or PUSCH as in Msg-1 and Msg-3) to BS 304. At 704, BS 304 transmits Msg-B (e.g., RAR together with contention resolution as in Msg-2 and Msg-4) to BS 304. At 706, UE 302 and BS 304 may optionally exchange user data. The processing of Msg-A and Msg-B is otherwise comparable to the processing of Msg-1, Msg-2, Msg-3 and Msg-4 in the procedure PRACH 4-Step 600 from Figure 6. In some designs, a 2-Step or 4-Step RACH procedure can be triggered by a PDCCH instruction. For PRACH transmissions triggered by a PDCCH command, the PRACH mask index field [5, TS 38.212], if the value of the random access preamble index field is non-zero, indicates a PRACH opportunity for PRACH transmission where the PRACH opportunity is associated with the SS / PBCH block index indicated by the SS / PBCH block index field of the PDCCH order. If random access is triggered by a PDCCH command, the UE, if requested via a higher layer signal, transmits a PRACH in the selected PRACH opportunity [TS 38.321], where the time between the last symbol of the PDCCH order reception and the first symbol of the PRACH transmission is >= NT,2+bBWPSwitch+bDelay, where the parameters are defined in TS 38.213 Section 8.1. If the DCI 1_0 format CRC is randomized by C-RNTI and the Frequency domain source assignment fields are all ones, the DCI 1_0 format is for a random access procedure initiated by a PDCCH command, with all remaining fields specified as follows: • Random Access Preamble Index - 6 bits according to raPreamblelndex in Clause 5.1.2 of [8, TS38.321] • UL / SUL Indicator - 1 bit. If the Index value The Random Access Preamble is not all zeros and if the UE is configured with supplementaryUplink in ServingCellConfig in the cell, this field indicates which UL carrier in the cell will transmit the PRACH according to Table 7.3.1.1.1-1; otherwise, this field is reserved. • SS / PBCH Index - 6 bits. If the Index value Random Access Preamble is not all zeros, this field indicates the SS / PBCH that will be used to determine the RACH opportunity for PRACH transmission; otherwise, this field is reserved. • PRACH mask index - 4 bits. If the Random Access Preamble Index value is not all zeros, this field indicates the RACH event associated with the SS / PBCH indicated by the SS / PBCH index for the PRACH transmission, according to Clause 5.1.1 of [8, TS38.321]; otherwise, this field is reserved • Reserved bits - 12 bits for operation in cells with shared spectrum channel access; otherwise 10 bits. As will be described below in more detail with respect to various embodiments of the present disclosure, a modified version of the PDCCH-triggered RACH procedure may be implemented wherein the partial RACH procedure is triggered by the PDCCH rather than the full RACH procedure. In some designs, the partial RACH procedure may be used specifically for positioning. As mentioned above, such embodiments provide the technical advantage of providing a rough location estimate more quickly particularly in scenarios where an active SRS configuration is not set for the UE. In addition, the use of the partial RACH procedure rather than the full RACH procedure may reduce system overhead and improve spectral efficiency (e.g., because only the RACH / PRACH preamble or Msg-1 / Msg-A need to be transmitted). Figure 8 illustrates an example of a wireless communication process 800, according to aspects of the present disclosure. The process 800 may be performed by UE 302. In 802, UE 302 (e.g., receiver 312, etc.) receives PDCCH communications. For example, PDCCH communications may be received from a serving BS 304 as part of a DCI communication. In the example, the means for performing the 802 reception may include a receiver 312. In 804, UE 302 (e.g., RACH component 344, processing system 332, transmitter 310, etc.) transmits, in response to a PDCCH communication, a partial RACH procedure. In an example, the partial RACH procedure may consist of transmitting a RACH signal for positioning (e.g., transmitting Msg-1 or Msg-A), while the partial RACH procedure is limited relative to the RACH procedures 600-700 in that the RACH procedure terminates after the transmission of the RACH preamble (e.g., Msg-2, Msg-3, Msg-4 are not transmitted for a 4-Step PRACH procedure, or Msg-B is not transmitted for a 2-Step PRACH procedure). In other designs, the partial RACH procedure may be triggered for purposes unrelated to positioning, such as coverage enhancement or UL beam sounding, or alternatively as a combination of both positioning and coverage enhancement or UL beam sounding. In an example, the means for performing the 804 transmission may include a transmitter 310. Figure 9 illustrates an example of a wireless communication process 900, according to aspects of the present disclosure. The process 900 may be performed by a BS 304, which may be a serving BS of the UE 302. At 902, BS 304 (e.g., transmitter 316, etc.) transmits to UE 302, a PDDCH communication configured to trigger a partial RACH procedure. In the example, the means for performing transmission 902 may include transmitter 316. At 904, the BS 304 (e.g., receiver 318, etc.) receives, from the UE 302 in response to the PDCCH communication, a RACH transmission. In an example, the RACH transmission may correspond to the transmission of Msg-1 or Msg-A, while the partial RACH procedure is limited relative to the RACH procedures 600-700 in that the RACH procedure terminates after the transmission of the RACH preamble (e.g., Msg-2, Msg-3, Msg-4 are not transmitted for a 4-Step PRACH procedure, or Msg-B is not transmitted for a 2-Step PRACH procedure). In some designs, the RACH transmission may correspond to a RACH transmission for positioning, with the BS 304 performing positioning measurements thereon. In other designs, the partial RACH procedure may be triggered for purposes unrelated to positioning, such as coverage enhancement or UL beam sounding, or alternatively as a combination of both positioning and coverage enhancement or UL beam sounding.In some designs where the RACH transmission is a RACH transmission for positioning, BS 304 may notify (e.g., via a backhaul connection) one or more non-serving BSs 302 with respect to the RACH transmission so that the non-serving BSs may also perform position measurements on the RACH transmission (e.g., which may be reported to a position estimation entity, such as an LMF integrated with BS 304 or remote from BS 304). In an example, the means for performing reception 904 may include a receiver 318. Figure 10 illustrates an example of a wireless communication process 1000, according to aspects of the present disclosure. The process 1000 may be performed by a BS 304, which may not be a serving BS of the UE 302. At 1002, the BS 304 (e.g., receiver 324, etc.) receives a RACH transmission indication from the UE associated with a partial RACH procedure. In some designs, the indication 1002 may be received from the UE's serving BS 302 via a backhaul connection. In the example, the means for performing the reception 1002 may include a receiver 324. At 1004, BS 304 (e.g., receiver 318, etc.) receives the RACH transmission based on the indication). In some designs, the RACH transmission may correspond to a RACH transmission for positioning, with BS 304 performing positioning measurements thereon (e.g., which may be reported to a position estimation entity, such as an LMF integrated with BS 304 or remote from BS 304). In an example, the means for performing the reception 1004 may include receiver 318. Figure 11 illustrates an example of a process 1100 of wireless communication, according to aspects of the present disclosure. The process 1100 may be performed by a position estimation entity, such as an LMF, which may be integrated with BS 304 (e.g., a UE serving BS 302) in some designs, or alternatively may be remote from BS 304, such as a network entity 306. In other designs, the position estimation entity may correspond to the UE itself (e.g., for UE-based positioning). At 1102, a position estimation entity 302 / 304 / 306 (e.g., a RACH component 344 or 348, a receiver 312 or 318 or 324 or 330, etc.) receives measurement data based on one or more positioning measurements performed by a set of BSs on RACH transmissions for positioning from the UE. In an example, the RACH transmission may be part of a partial RACH procedure, although in other designs the RACH transmission may be part of a full PDCCH-triggered RACH procedure for the position measurements performed. In an example, the means for performing the reception 1102 may include a RACH component 344 or 348, and / or a receiver 312 or 318 or 324 or 330. At 1104, the position estimation entity 302 / 304 / 306 (e.g., positioning component 349 or processing system 332 or 334 or 336) determines the UE's positioning estimate based at least in part on the measurement data. In an example, the means for performing the reception 1104 may include positioning component 349 and / or processing system 332 or 334 or 336. Figure 12 illustrates an example implementation 1200 of processes 800-1100 in accordance with aspects of the present disclosure. Specifically, the example implementation 1200 relates to a scenario where a position estimation entity corresponding to the LMF is integrated with the rendering BS 304. Referring to Figure 12, at 1202 (e.g., as in 1002 of Figure 11), the serving BS 304 notifies the non-serving BS of an upcoming RACH transmission for positioning from UE 302. At 1204 (e.g., as in 802 of Figure 8 or 902 of Figure 9), the serving BS 304 transmits a PDCCH configured to trigger a partial RACH procedure to UE 302. At 1206 (e.g., as in 804 of Figure 8 or 904 of Figure 9 or 1004 of Figure 10), UE 302 transmits a PRACH preamble (e.g., Msg-1 or Msg-A) in response to the PDCCH from 1204. At 1208, the serving BS 304 performs a position measurement on the PRACH preamble. At 1210, the non-presenting BS 304 performs position measurements on the PRACH preamble. At 1212 (e.g., as at 1102 of FIG. 11), because the LMF is integrated with the presenting BS 304, the non-presenting BS 304 sends measurement data to the LMF on the presenting BS 304.At 1214 (e.g., as at 1104 of FIG. 11), the LMF at the serving BS 304 determines a positioning estimate for the UE 302 based on measurement data received from the non-serving BS at 1212 as well as measurement data obtained based on positioning measurements from 1208 at the serving BS 304. Figure 13 illustrates an example implementation 1300 of the processes 800-1100 in accordance with aspects of the present disclosure. Specifically, the example implementation 1300 relates to a scenario where the position estimation entity corresponding to the LMF is integrated with a network entity 306 that is remote from the serving BS 304 and not the serving BS 304. Referring to Figure 13, at 1302 (e.g., as in 1002 of Figure 11), the serving BS 304 notifies the non-serving BS of an upcoming RACH transmission for positioning from UE 302. At 1304 (e.g., as in 802 of Figure 8 or 902 of Figure 9), the serving BS 304 transmits a PDCCH configured to trigger a partial RACH procedure to UE 302. At 1306 (e.g., as in 804 of Figure 8 or 904 of Figure 9 or 1004 of Figure 10), UE 302 transmits a preamble PRACH (e.g., Msg-1 or Msg-A) in response to the PDCCH from 1304. At 1308, the serving BS 304 performs position measurements on the PRACH preamble. At 1310, the non-serving BS 304 performs positioning measurements on the PRACH preamble. At 1312-1314 (e.g., as in 1102 of FIG. 11), because the LMF is integrated with the network entity 306, the serving BS 304 and the non-serving BS 304 send measurement data to the LMF 306. At 1316 (e.g., as in 1104 of FIG. 11), the LMF 306 determines an approximate position for UE 302 based on the measurement data received at 1312-1314. Referring to Figure 8-13, in some designs, a partial RACH procedure may be triggered responsively to the configuration of a PDCCH communication. For example, a partial RACH procedure may be triggered responsively to at least one field of a PDCCH communication. In some designs, at least one field may comprise a radio network temporary identifier (RNTI), or at least one field may be part of a DCI communication, or a combination thereof. In some designs, at least one field in the DCI communication may comprise a first value, with the partial RACH procedure consisting of a RACH transmission with a first configuration based on the first value. Another DCI communication may then be transported with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure consisting of another RACH transmission with a second configuration based on the second value.For example, at least one field may be part of the existing DCI format 1_0 which is currently scrambled with C-RNTI and FDRA set to all for the PDCCH order-based RA Preamble, and may instead be scrambled with other bit combinations (or values) to indicate RACH for positioning or partial RACH procedures. For example, the first and second configurations may correspond to different configurations of one or more PRACH preambles (Msg-1 or Msg-A), including but not limited to the following:. • Opening Format, • Length of sequence (e.g., denoted as L in Figure 4A-4B), • Numerology or sub-carrier spacing (SCS), • bandwidth, • Cyclic Prefix Duration (CP), • Guard Time Duration (GT), • Total length, and / or • Number of OFDM symbols. Referring to Figure 8-13, in some designs, partial RACH procedures can be triggered responsively to the PDCCH communication size (e.g., a new DCI size specific to the RACH for positioning or partial RACH procedures). Referring to Figure 8-13, in some designs, the PDCCH that triggers a partial RACH procedure can be part of a sequence of DCIs, each associated with different parameters to transmit multiple RACH instances (or multiple RACH procedures). Referring to Figure 8-13, in some designs, a partial RACH procedure can be part of a joint DL and UL positioning procedure. For example, the PDCCH of the DCI that triggers the downlink portion (e.g., DL PRS transmission) of a joint DL and UL positioning procedure can be further configured to trigger the uplink portion (e.g., UL RACH, or partial RACH procedure for positioning) of a joint DL and UL positioning procedure. Referring to Figure 8-13, in some designs, the partial RACH procedure may consist of: • RACH transmissions transmitted on one or more beams corresponding to a number of synchronization signal blocks (SSBs) (e.g., more than one SSB index is mapped to the same UL beam, UE transmits only once), • RACH transmissions transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on the number of frequency layers configured for the UE (e.g., up to 4 frequency layers may be used for positioning in some designs, and the gNB may present RACH occasions up to the number of frequency layers configured for the UE to transmit UL PRS; note: in general, parallel RACH transmissions are not allowed and therefore the UE may have to transmit TDM on multiple frequencies), • repeat transmissions of RACH preambles across multiple RACH or PRACH occasions (e.g., this may increase the link budget (or) improve resolution if the PRACH occasions are on different frequency sources), or • any combination thereof. Referring to Figure 8-13, in some designs, the RACH procedure may be based on time offsets indicated via PDCCH communication. For example, time offsets associated with UE Rx-Tx measurements or gNB Rx-Tx measurements (e.g., hardware / circuit delays between receive and transmit used in various positioning measurements such as RTT, TDOA, etc.). In another example, if the RACH signal is transmitted as part of a UL TDoA / AoA procedure, then the gNB may provide relevant information about the timing to the LMF. In another example, if the RACH signal is transmitted as part of RTT / AoD, then the gNB or UE may provide timing information to the LMF (depending on the node initiating the procedure). Since the LMF may generally not be aware of triggering based on the PDCCH sequence, the serving gNB may inform the LMF and / or other nearby gNBs to listen for the UE RACH transmission (e.g., as in 1202 in Figure 12 or 1302 in Figure 13). Referring to Figure 8-13, in some designs where the RACH transmission of a partial RACH procedure consists of a MsgA (e.g., the PRACH preamble for a 2-Step PRACH procedure), relevant information such as a DL measurement or a UL timing reference may be transmitted on the PUSCH (or Msg-3 component) of the Msg-A, which may be taken into account in the timing at the serving BS 304. Referring to Figure 8-13, in some designs, RACH transmissions from a partial RACH procedure may be transmitted over licensed spectrum licensed to a specific radio access technology (RAT) (e.g., LTE, 5G NR, etc.). In other designs, RACH transmissions may be transmitted over shared spectrum shared by a number of RATs (e.g., LTE, 5G NR, Wi-Fi or 802.11, etc.). In the above comprehensive description, it can be seen that different features are grouped together in the examples. This manner of expression should not be understood to mean that the example clauses have more features than are explicitly mentioned in each clause. On the contrary, the various aspects of this expression may encompass fewer than all the features of the individual example clauses expressed. Therefore, the following clauses should be considered included in the description, each clause by itself being able to stand as a separate example. Although each dependent clause may refer in a clause to a specific combination with one of the other clauses, the aspects of that dependent clause are not limited to that specific combination.It will be appreciated that other example clauses may also include combinations of aspects of a dependent clause with the subject matter of other dependent or independent clauses or combinations of any features with other dependent and independent clauses. The various aspects expressed here expressly include these combinations, unless it is explicitly stated or it can easily be inferred that a particular combination is not intended (e.g., contradictory aspects, such as defining elements as insulators and conductors). Furthermore, it is also intended that aspects of clauses may be included in other independent clauses, even though those clauses are not directly dependent on the independent clause. An example implementation is described in the following numbered clauses: Clause 1. Method of operation of user equipment (UE), comprising: receiving a physical downlink control channel (PDCCH) communication; and triggering, in response to the PDCCH communication, a partial random access channel (RACH) procedure. Clause 2. The method according to clause 1, wherein the partial RACH procedure comprises transmitting a RACH signal for positioning. Clause 3. The method according to clause 2, wherein the RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one non-serving BS of the UE. Clause 4. Method according to one of clauses 1 to 3, wherein the trigger is responsive to the PDCCH communication configuration. Clause 5. The method according to clause 4, wherein the trigger is responsive to at least one PDCCH communication field. Clause 6. The method according to clause 5, wherein at least one field comprises a radio network temporary identifier (RNTI), or wherein at least one field is part of a downlink control information (DCI) communication, or a combination thereof. Clause 7. A method according to any one of clauses 5 to 6, wherein at least one field in the DCI communication comprises a first value, a partial RACH procedure comprising a RACH transmission with a first configuration based on the first value, further comprising: receiving another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. Clause 8. Method according to any one of clauses 4 to 7, wherein the trigger is responsive to the PDCCH communication size. Clause 9. Method according to any one of clauses 1 to 8, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble. Clause 10. A method according to any one of clauses 1 to 9, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. Clause 11. Method according to any one of clauses 1 to 10, wherein the UE does not have an active voice reference signal (SRS) configuration to trigger SRS transmission for positioning during reception and triggering. Clause 12. Method according to any one of clauses 1 to 11, wherein the partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSB), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the number of one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeat transmissions of the RACH preamble across the multiple RACH occasions, or a combination thereof. Clause 13. The method of each of clauses 1 to 12, wherein the RACH procedure is based on the time offset indicated via PDCCH communication. Clause 14. Methods according to any one of Clauses 1 to 13, where the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or where the RACH procedure is performed over shared spectrum shared by a number of RATs. Clause 15. A method according to any one of clauses 1 to 14, wherein the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. Clause 16. Method of operation of a serving base station (BS) of user equipment (UE), comprising: transmitting, to the UE, a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receiving, from the UE in response to the PDCCH communication, a RACH transmission. Clause 17. The method according to clause 16, where the RACH transmission is for positioning, further comprises: performing one or more position measurements on the RACH transmission. Clause 18. The method according to clause 17, wherein the RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE. Clause 19. The method according to Clause 18, further comprising: notifying at least one serving non-BS or location management function (LMF) of a partial RACH procedure to facilitate at least one serving non-BS to perform positioning measurements on a RACH transmission. Clause 20. Method according to one of clauses 17 to 19, further comprising: sending measurement data based on one or more position measurements to a position estimation entity. Clause 21. The method of any one of clauses 16 to 20, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration. Clause 22. The method according to clause 21, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication. Clause 23. The method according to clause 22, wherein at least one field comprises a radio network temporary identifier (RNTI), or wherein at least one field is part of a downlink control information (DCI) communication, or a combination thereof. Clause 24. The method according to clause 23, wherein at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, further comprising: transmitting another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value. Clause 25. The method according to clauses 22 to 24, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication. Clause 26. Method according to any one of clauses 16 to 25, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises receiving a RACH preamble only without a RACH response to the RACH preamble. Clause 27. A method according to any one of clauses 16 to 26, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. Clause 28. The method according to each of clauses 16 to 27, wherein the UE does not have an active sounding reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception. Clause 29. A method according to any one of clauses 16 to 28, wherein the RACH transmission is received on one or more beams corresponding to a plurality of synchronization signal blocks (SSB), wherein the RACH transmission is received over one or more frequency layers on one or more individual RACH occasions, the plurality of the one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating the RACH preamble across the plurality of RACH occasions, or any combination thereof. Clause 30. The methods according to clauses 16 to 29, wherein the RACH procedure may be based on a time offset indicated via PDCCH communication. Clause 31. A method according to any one of clauses 16 to 30, wherein the RACH transmission is received over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs. Clause 32. A method according to any one of clauses 16 to 31, wherein the partial RACH procedure is the uplink portion of a joint uplink and downlink positioning procedure, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure. Clause 33. Method of operation of a non-servicing base station (BS) of user equipment (UE), comprising: receiving a random access channel (RACH) transmission indication from the UE associated with a partial RACH procedure; and receiving a RACH transmission based on the indication. Clause 34. The method according to clause 33, where the RACH transmission is for positioning, further comprises: performing one or more position measurements on the RACH transmission. Clause 35. The method according to clause 34, further comprising: transmitting measurement data based on one or more position measurements to a position estimation entity. Clause 36. A method according to any one of clauses 33 to 35, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble. Clause 37. A method according to any one of clauses 33 to 36, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. Clause 38. A method according to any one of clauses 33 to 37, wherein the RACH transmission is received over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs. Clause 39. The method according to any one of clauses 16 to 38, wherein the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedure. Clause 40. A method of operating a position estimation entity, comprising: receiving measurement data based on one or more positioning measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UE); and determining an estimate of the UE's position based at least in part on the measurement data. Clause 41. The method according to clause 40, where the transmission RACH is associated with the partial RACH procedure. Clause 42. The method according to clause 41, wherein the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS. Clause 43. The method according to any one of clauses 41 to 42, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble. Clause 44. A method according to any one of clauses 41 to 43, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication. Clause 45. A method according to any one of clauses 41 to 44, wherein the RACH transmission for positioning is transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum owned by a plurality of RATs. Clause 46. An apparatus comprising a memory and at least one processor communicatively coupled to the memory, the memory and at least one processor being configured to perform a method in accordance with any one of clauses 1 to 45. Clause 47. An apparatus comprising means for carrying out a method according to one of clauses 1 to 45. Clause 48. A computer-readable fixed medium that stores computer-executable instructions, the computer-executable comprising at least one instruction to cause a computer or processor to perform a method in accordance with one of clauses 1 to 45. Experts in this field will appreciate that information and signals can be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or combinations thereof. Furthermore, those skilled in the art will appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this hardware-software interchangeability, the various illustrative components, blocks, modules, circuits, and steps have been described above in general terms in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for any particular application, but such implementation decisions should not be construed as causing a departure from the scope of the present disclosure. The various illustrative blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or combinations thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, a processor may be a conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or other such configurations. The methods, sequences, and / or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in software modules executed by the processor, or in a combination of both. The software modules may reside in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable ROM (EEPROM), registers, hard disks, removable disks, CD-ROMs, or other forms of storage media known in the art. Example storage media are coupled to the processor such that the processor can read information from, and write information to, the storage media. Alternatively, the storage media may be an integral part of the processor. The processor and storage media may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE).Alternatively, the processor and storage media can reside as separate components in the user terminal. In one or more exemplary aspects, the described functionality may be implemented in hardware, software, firmware, or a combination thereof. If implemented in software, the functionality may be stored or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable medium includes computer storage media and communication media including any medium that facilitates the transfer of computer programs from one location to another. The storage medium may be any available medium accessible by a computer.For example, and without limitation, such computer-readable media may consist of RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and is accessible by a computer. Also, any connection is properly called a computer-readable medium. For example, if software is transmitted from a network site, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium.Disks and discs, as used herein, include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while discs reproduce data optically with a laser. Combinations of the above shall also be included within the scope of computer-readable media. While the above disclosure shows illustrative aspects of the disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps and / or actions of the method claims according to the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is considered unless a limitation on the singular is explicitly stated.

Claims

1. A method of operating user equipment (UE), comprising: receiving a physical downlink control channel (PDCCH) communication; and triggering, in response to the PDCCH communication, a partial random access channel (RACH) procedure.

2. The method according to claim 1, wherein the partial RACH procedure comprises transmitting a RACH signal for positioning.

3. The method according to claim 2, wherein the RACH signal for positioning is targeted to a serving base station (BS) of the UE and at least one non-serving BS of the UE.

4. The method according to claim 1, wherein the trigger is responsive to the PDCCH communication configuration.

5. The method according to claim 4, wherein the trigger is responsive to at least one PDCCH communication field.

6. The method according to claim 5, wherein the at least one field comprises a radio network temporary identifier (RNTI), or wherein the at least one field is part of a downlink control information (DCI) communication, or any combination thereof.

7. The method according to claim 6, wherein at least one field in the DCI communication comprises a first value, the partial RACH procedure comprising a RACH transmission with a first configuration based on the first value, further comprising: receiving another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value.

8. The method according to claim 4, wherein the trigger is responsive to the size of the PDCCH communication.

9. The method according to claim 1, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting the RACH preamble only without a RACH response to the RACH preamble.

10. The method according to claim 1, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

11. The method according to claim 1, wherein the UE does not have an active sounding reference signal (SRS) configuration to trigger the SRS transmission for positioning during reception and triggering.

12. The method according to claim 1, wherein the partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the plurality of the one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the plurality of RACH occasions, or any combination thereof.

13. The method according to claim 1, wherein the RACH procedure is based on a time offset indicated via PDCCH communication.

14. The method according to claim 1, wherein the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH procedure is performed over shared spectrum shared by a plurality of RATs.

15. The method according to claim 1, wherein the partial RACH procedure is an uplink portion of the joint uplink and downlink positioning procedure, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure.

16. A method of operating a serving base station (BS) comprising: transmitting, to a user equipment (UE), a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receiving, from the UE in response to the PDCCH communication, a RACH transmission.

17. The method according to claim 16, wherein the RACH transmission is for positioning, further comprising: performing one or more position measurements on the RACH transmission.

18. The method according to claim 17, wherein the RACH signal for positioning is targeted to a serving BS of the UE and at least one non-serving BS of the UE.

19. The method according to claim 18, further comprising: notifying at least one serving non-BS or location management function (LMF) of a partial RACH procedure to facilitate at least one serving non-BS to perform positioning measurements on the RACH transmission.

20. The method according to claim 17, further comprising: transmitting measurement data based on the one or more position measurements to the position estimation entity.

21. The method according to claim 16, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration.

22. The method according to claim 21, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on at least one field of the PDCCH communication.

23. The method according to claim 22, wherein the at least one field comprises a radio network temporary identifier (RNTI), or wherein the at least one field is part of a downlink control information (DCI) communication, or any combination thereof.

24. The method according to claim 23, wherein at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, further comprising: transmitting another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value.

25. The method according to claim 22, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication.

26. The method according to claim 16, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises receiving a RACH preamble only without a RACH response to the RACH preamble.

27. The method according to claim 16, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

28. The method according to claim 16, wherein the UE does not have an active sounding reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception.

29. The method according to claim 16, wherein the RACH transmission is received on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of the one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the RACH transmission comprises repeating the RACH preamble across the plurality of RACH occasions, or any combination thereof.

30. The method according to claim 16, wherein the RACH procedure may be based on a time offset indicated via PDCCH communication.

31. The method according to claim 16, wherein the RACH transmission is received over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs.

32. The method according to claim 16, wherein the partial RACH procedure is an uplink portion of the joint uplink and downlink positioning procedure, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure.

33. A method of operating a non-presenting BS, comprising: receiving a random access channel (RACH) transmission indication from a user equipment (UE) associated with a partial RACH procedure; and receiving a RACH transmission based on the indication.

34. The method according to claim 33, wherein the RACH transmission is for positioning, further comprising: performing one or more position measurements on the RACH transmission.

35. The method according to claim 34, further comprising: transmitting measurement data based on the one or more position measurements to the position estimation entity.

36. The method according to claim 33, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble.

37. The method according to claim 33, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

38. The method according to claim 33, wherein the RACH transmission is received over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs.

39. The method according to claim 16, wherein the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedures.

40. A method of operating a position estimation entity, comprising: receiving measurement data based on one or more positioning measurements performed by a set of base stations (BSs) on a random access channel (RACH) transmission for positioning from user equipment (UE); and determining an estimate of the UE's position based at least in part on the measurement data.

41. The method according to claim 40, wherein the RACH transmission is associated with a partial RACH procedure.

42. The method according to claim 41, wherein the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE serving BS.

43. The method according to claim 41, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble.

44. The method according to claim 41, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or the PUSCH communication.

45. The method according to claim 41, wherein the RACH transmission for positioning is transmitted by the UE over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs.

46. ​​A user equipment (UE), comprising: a memory; a communications interface; and at least one processor communicatively coupled to the memory and the communications interface, the at least one processor configured to: receive, via the communications interface, a physical downlink control channel (PDCCH) communication; and trigger, in response to the PDCCH communication, a partial random access channel (RACH) procedure.

47. The UE according to claim 46, wherein the partial RACH procedure comprises transmitting a RACH signal for positioning.

48. The UE according to claim 47, wherein the RACH signals for positioning are targeted to a serving base station (BS) of the UE and at least one serving non-BS of the UE.

49. The UE according to claim 46, wherein the trigger is responsive to the PDCCH communication configuration.

50. The UE according to claim 49, wherein the trigger is responsive to at least one PDCCH communication field.

51. The UE according to claim 50, wherein the at least one field comprises a radio network temporary identifier (RNTI), or wherein the at least one field is part of a downlink control information (DCI) communication, or any combination thereof.

52. The UE according to claim 51, wherein at least one field in the DCI communication comprises a first value, the partial RACH procedure comprising a RACH transmission with a first configuration based on the first value, further comprising: receiving, via the communication interface, another DCI communication with at least one field comprising a second value, the other DCI communication triggering another partial RACH procedure comprising another RACH transmission with a second configuration based on the second value.

53. The UE according to claim 49, wherein the trigger is responsive to the size of the PDCCH communication.

54. The UE according to claim 46, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting only a RACH preamble without a RACH response to the RACH preamble.

55. The UE according to claim 46, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises the transmission of a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or the PUSCH communication.

56. The UE according to claim 46, wherein the UE does not have an active voice reference signal (SRS) configuration to trigger the SRS transmission for positioning during reception and triggering.

57. The UE according to claim 46, wherein the partial RACH procedure comprises a RACH transmission transmitted on one or more beams corresponding to a plurality of synchronization signal blocks (SSBs), wherein the partial RACH procedure comprises a RACH transmission transmitted over one or more frequency layers on one or more RACH occasions each, the plurality of the one or more frequency layers being based on a plurality of frequency layers configured for the UE, wherein the partial RACH procedure comprises repeating transmissions of the RACH preamble across the plurality of RACH occasions, or any combination thereof.

58. The UE according to claim 46, wherein the RACH procedure is based on a time offset indicated via PDCCH communication.

59. The UE according to claim 46, wherein the RACH procedure is performed over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH procedure is performed over shared spectrum shared by a plurality of RATs.

60. The UE according to claim 46, wherein the partial RACH procedure is an uplink portion of the 100 joint uplink and downlink positioning procedures, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedures.

61. A base station, comprising: a memory; a communications interface; and at least one processor communicatively coupled to the memory and the communications interface, the at least one processor configured to: cause the communications interface to transmit, to a user equipment (UE), a physical downlink control channel (PDCCH) communication configured to trigger a partial random access channel (RACH) procedure; and receive, via the communications interface, from the UE in response to the PDCCH communication, a RACH transmission.

62. The base station according to claim 61, wherein the RACH transmission is for positioning, wherein the at least one processor is further configured to: perform one or more RACH transmissions. position measurements on 63. The base station according to claim 62, wherein the RACH signals for positioning are targeted to a serving BS of the UE and at least one non-serving BS of the UE.

64. The base station according to claim 63, wherein the at least one processor is further configured to: notify the at least one non-BS presenter or location management function (LMF) of a partial RACH procedure to facilitate the at least one non-BS presenter 101 to perform positioning measurements on the RACH transmission.

65. The base station according to claim 62, wherein the at least one processor is further configured to: cause the communication interface to send measurement data based on the one or more position measurements to the position estimation entity.

66. The base station according to claim 61, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the PDCCH communication configuration.

67. The base station according to claim 66, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on at least one PDCCH communication field.

68. The base station according to claim 67, wherein at least one field comprises a radio network temporary identifier (RNTI), or wherein at least one field is part of a downlink control information (DCI) communication, or any combination thereof.

69. The base station according to claim 68, wherein at least one field in the DCI communication comprises a first value, the RACH transmission is configured with a first configuration based on the first value, wherein the at least one processor is further configured to: cause the communication interface to transmit another DCI communication with at least one field comprising a second value, the other DCI communication being configured to trigger another partial RACH procedure 102 comprising another RACH transmission with a second configuration based on the second value.

70. The base station according to claim 67, wherein the PDCCH communication is configured to trigger a partial RACH procedure based on the size of the PDCCH communication.

71. The base station according to claim 61, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises receiving only a RACH preamble without a RACH response to the RACH preamble.

72. The base station according to claim 61, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises receiving a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

73. The base station according to claim 61, wherein the UE does not have an active sounding reference signal (SRS) configuration to trigger SRS transmission for positioning during transmission and reception.

74. The base station according to claim 61, wherein the RACH transmission is received on one or more beams corresponding to a plurality of synchronization signal blocks (SSB), wherein the RACH transmission is received over one or more frequency layers on one or more RACH occasions each, the plurality of the one or more frequency layers being based on a plurality of frequency layers 103 configured for the UE, wherein the RACH transmission comprises repeating the RACH preamble across the plurality of RACH occasions, or any combination thereof.

75. The base station according to claim 61, wherein the RACH procedure may be based on a time offset indicated via the PDCCH communication.

76. The base station according to claim 61, wherein the RACH transmission is received over licensed spectrum licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs.

77. The base station according to claim 61, wherein the partial RACH procedure is an uplink portion of the joint uplink and downlink positioning procedure, and wherein the PDCCH is further configured to trigger the downlink portion of the joint uplink and downlink positioning procedure.

78. The base station according to claim 55, wherein the partial RACH procedure is the uplink portion of the joint uplink and downlink positioning procedures.

79. A base station, comprising: a memory; a communications interface; and at least one processor communicatively coupled to the memory and communications interface, the at least one processor being configured to: receive, via the communications interface, random access channel (RACH) transmission indications from user equipment (UE) 104 associated with a partial RACH procedure; and receive, via the communications interface, RACH transmissions based on the indications.

80. The base station according to claim 79, wherein the RACH transmission is for positioning, wherein the at least one processor is further configured to: perform one or more position measurements on the RACH transmission.

81. The base station according to claim 80, wherein the at least one processor is further configured to: cause the communication interface to send measurement data based on the one or more position measurements to the position estimation entity.

82. The base station according to claim 79, wherein the partial RACH procedure is a partial 4-Step RACH procedure, wherein the partial RACH procedure comprises transmitting a RACH preamble only without a RACH response to the RACH preamble.

83. The base station according to claim 79, wherein the partial RACH procedure is a partial 2-Step RACH procedure, and wherein the partial RACH procedure comprises transmitting a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

84. The base station according to claim 79, wherein the RACH transmission is received over licensed spectrum 105 85.

86.

87. licensed to a particular radio access technology (RAT), or wherein the RACH transmission is received over shared spectrum shared by a plurality of RATs. A position estimation entity, comprising: a memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor configured to: receive, via the communication interface, measurement data based on one or more positioning measurements performed by a set of base stations (BSs) on random access channel (RACH) transmissions for positioning from user equipment (UEs); and determine an estimate of the UE's position based at least in part on the measurement data. The position estimation entity of claim 85, wherein the RACH transmission is associated with a partial RACH procedure.A position estimation entity according to claim 86, wherein the partial RACH procedure is triggered by a physical downlink control channel (PDCCH) communication from the UE's serving BS.

88. A position estimation entity according to claim 86, wherein the partial procedure Step, partial RACH is a 4-step RACH procedure wherein the partial RACH procedure comprises the transmission of a RACH preamble only without a RACH response to the RACH preamble.

89. A position estimation entity according to claim 86, wherein the partial RACH procedure is a 2-step RACH procedure, and wherein the partial RACH procedure comprises the transmission of a RACH preamble and a physical uplink shared channel (PUSCH) communication without a RACH response to the RACH preamble or PUSCH communication.

90. A position estimation entity according to claim 86, wherein the RACH transmission for positioning is transmitted by the UE over a licensed spectrum licensed 10 to a particular radio access technology (RAT), or wherein the RACH transmission is received over a shared spectrum shared by a plurality of RATs.

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