WO2018130873A2

WO2018130873A2 - Random access measurement indication

Info

Publication number: WO2018130873A2
Application number: PCT/IB2017/001782
Authority: WO
Inventors: Patrick Svedman
Original assignee: Zte Wistron Telecom Ab
Priority date: 2016-11-04
Filing date: 2017-11-03
Publication date: 2018-07-19
Also published as: WO2018130873A3

Abstract

A system and method for random access measurement indications are disclosed herein. In one embodiment, a method performed by a first communication node includes: obtaining measurement results from a plurality of signals; determining a matching measurement result of the measurement results that corresponds to a matching signal of the plurality of signals, wherein the matching measurement result best matches with a criteria; selecting determining random access channel (RACH) resources based on the matching signal; sending a first message using the RACH resources; and receiving a second message based on the matching signal.

Description

RANDOM ACCESS MEASUREMENT INDICATION

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 62/417,957 entitled "BEST MEASUREMENT INDICATION IN RANDOM ACCESS" filed on November 4, 2016, the contents of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] This disclosure relates generally to wireless communications and, more particularly, to systems and methods for random access.

BACKGROUND

[0003] Random access in wireless systems may be utilized to initiate and facilitate communication between user equipment (UE) with a network. This network may include a base station (BS) that the UE interacts with, and a core network or other network equipment and functions which may provide wireless communication services for the UE. For example, random access may enable a UE to extract timing and frequency (phase) information for timing synchronization and initial frequency correction.

[0004] Traditionally, random access may be performed in accordance with a four message random access procedure. This four message random access procedure may include multiple operations, which are numerated below for ease of explanation. For example, as a first operation, downlink signals (DL) may be broadcast by a network. These broadcasted signals may be periodically transmitted. Also, such broadcasted signals may include synchronization signal(s) (SS), reference signal(s) (RS), and broadcast channel(s) (BCH) that each carry system information (SI).

[0005] As a second operation, user equipment (UE) may receive the broadcasted signals from the system. The UE may use SS and RS for obtaining DL time/frequency synchronization information as discussed above. Furthermore, the UE may decode a BCH to obtain SI.

[0006] As a third operation, UEs in an IDLE state (e.g. as used in the Long Term Evolution (LTE) telecommunication standard), such as UEs accessing the network for the first time, may rely on the broadcasted signals and information therein to access the network (e.g., a BS in the network). However, UEs that have previously accessed the network may be in a CONNECTED state (e.g. as used in LTE). In a CONNECTED state, the UE may receive further UE-specific configuration based on the broadcasted signals.

[0007] As a fourth operation, based on the received signals, the UE may select a subset of RACH resources for RACH preamble transmission. A RACH resource may be a combination of a RACH occasion and a set of eligible RACH preambles. A RACH occasion may be a time- frequency resource on which a RACH preamble may be transmitted. The set of eligible preambles may be predefined in some cases. The set of eligible preambles may be indicated in the SI in some cases. The set of eligible preambles can be indicated in a UE-specific configuration in some cases. Also, a subset of RACH resources may be a set of disjoint RACH resources (e.g., where a certain combination of a RACH occasion and a preamble is present in no more than one set of RACH resources). A subset of RACH resources may be smaller than the set of all RACH resources. Different subsets of RACH resources may be selected depending on the received signals, for instance depending on SI. In some cases, the UE-specific configuration of a CONNECTED UE may configure the UE selection of a subset of RACH resources. [0008] As a fifth operation, the UE may select a RACH occasion belonging to the selected subset of RACH resources. The UE may also select a preamble for transmission on the selected RACH occasion. The combination of the selected preamble and RACH occasion may belong to the subset of RACH resources. Also, the RACH occasion may be selected as the closest occasion in time, in order to reduce the time delay until preamble transmission. Furthennore, the preamble may be selected randomly from a set of eligible preambles.

[0009] As a sixth operation, the UE may transmit the selected preamble on the selected RACH occasion. Since the preamble is the first message in this random access procedure with four messages, it can also be referred to as MSG1.

[0010] As a seventh operation that is optional, in some cases, multiple preambles may be transmitted by the UE. In such cases, the fifth and sixth operations may be repeated, such that multiple preambles are transmitted on multiple different RACH occasions. Stated another way, the seventh operation may represent a repeat of the fifth and sixth operations.

[0011] As an eighth operation, in response to a detected preamble, the network may transmit a random access response (RAR). As this is a second message of this four message random access procedure, the RAR may also be referred to as MSG2.

[0012] As a ninth operation, in response to a received MSG2, the UE may respond with a third message referred to as MSG3.

[0013] As a tenth operation, another message from the network to the UE may be transmitted and be referred to as MSG4.

[0014] In addition to the above referenced traditional four message random access procedure, some random access procedures may be referred to as two message random access procedures. These two message random access procedures may be an adaptation of the above referenced four message random access procedure by updating the sixth operation (referenced above) such that the UE transmits the selected preamble together with some data on the RACH occasion. The data may include parts of MSG3 of the four message random access procedure (thereby combining MSG3 into MSG1 ). Also, the first message in the two message random access procedure may be referred to as MSG 1 2.

[0015] Also, the two message random access procedures may include an adaptation of the above referenced four message random access procedure by updating the eighth operation (referenced above) to instead transmit a response message, that will be referred to as MSG2_2, from the network in response to a detected MSG1_2. This response may include parts of MSG2 and MSG4 in the four message random access procedure (thereby combining MSG4 into MSG2). Accordingly, the ninth and tenth operations in the four message random access procedure need not be performed in two message random access procedures.

SUMMARY OF THE INVENTION

[0016] The exemplary embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the invention. [0017] In one embodiment, a method performed by a first communication node includes: obtaining measurement results from a plurality of signals; determining a matching measurement result of the measurement results that corresponds to a matching signal of the plurality of signals, wherein the matching measurement result best matches with a criteria; selecting determining random access channel (RACH) resources based on the matching signal; sending a first message using the RACH resources; and receiving a second message based on the matching signal.

[0018] In a further embodiment, a method performed by a first communication node includes: transmitting a plurality of signals; receiving a first message on a plurality of random access channel (RACH) resources; detemiining a matching signal of the plurality of signals based on the RACH resources; and transmitting a second message based on the matching signal.

[0019] In another embodiment, an apparatus includes: a transceiver configured to: receive a plurality of signals; and at least one processor configured to: obtain measurement results from the plurality of signals, determine a matching measurement result of the measurement results that corresponds to a matching signal of the plurality of signals, wherein the matching measurement result best matches with a criteria, determine random access channel (RACH) resources based on the matching signal, send, using the transceiver, a first message using the RACH resources, and receive, using the transceiver, a second message based on the matching signal.

[0020] In yet another embodiment, an apparatus includes: a transceiver configured to: transmit a plurality of signals, and receive a first message on a plurality of random access channel (RACH) resources; and a processor configured to: determine a matching signal of the plurality of signals based on the RACH resources; and transmit, using the transceiver, a second message based on the matching signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various exemplary embodiments of the invention are described in detail below with reference to the following Figures. The drawings are provided for purposes of illustration only and merely depict exemplary embodiments of the invention to facilitate the reader's understanding of the invention. Therefore, the drawings should not be considered limiting of the breadth, scope, or applicability of the invention. It should be noted that for clarity and ease of illustration these drawings are not necessarily drawn to scale.

[0022] Figure 1 illustrates an exemplary cellular communication network in which techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure.

[0023] Figure 2 illustrates block diagrams of an exemplary base station and a user equipment device, in accordance with some embodiments of the present disclosure.

[0024] Figure 3 is a block diagram that illustrates a user equipment (UE) performing measurements on downlink (DL) signals, in accordance with some embodiments of the present disclosure.

[0025] Figure 4 is a block diagram that illustrates DL signals, in accordance with some embodiments of the present disclosure.

[0026] Figure 5 is a block diagram that illustrates beamforming in an synchronization signal (SS) burst and SS burst set, in accordance with some embodiments of the present disclosure.

[0027] Figure 6 is a block diagram that illustrates how measurement results may be mapped to random access channel (RACH) occasions, in accordance with some embodiments of the present disclosure. [0028] Figure 7 is a block diagram that illustrates how SS blocks may be associated with a subset of RACH occasions, in accordance with some embodiments of the present disclosure.

[0029] Figure 8 is a block diagram that illustrates how multiple measurement results may be mapped to particular RACH occasions, in accordance with some embodiments of the present disclosure.

[0030] Figure 9 is a block diagram that illustrates an association between SS blocks and RACH occasions, in accordance with some embodiments of the present disclosure.

[0031] Figure 10 is a block diagram that illustrates an association between measurement results and RACH occasions, in accordance with some embodiments of the present disclosure.

[0032] Figure 1 1 is a block diagram illustrating an association between SS blocks and a subset of RACH occasions, in accordance with some embodiments of the present disclosure.

[0033] Figure 12 is a block diagram that illustrates associations between measurement results and disjoint subsets of RACH resources, in accordance with some embodiments of the present disclosure.

[0034] Figure 13 is a block diagram that illustrates twelve disjoint subsets of RACH resources (e.g. M=12), in accordance with some embodiments of the present disclosure.

[0035] Figures 14A-14C are block diagrams that illustrates embodiments of the four disjoint subsets of RACH occasions in Figure 13), in accordance with some embodiments of the present disclosure.

[0036] Figure 15 is a block diagram that illustrates associations between measurement results and disjoint subsets of RACH resources, in accordance with some embodiments of the present disclosure. [0037] Figure 16 is a block diagram that illustrates associations between multiple measurement results and disjoint subsets of RACH resources, in accordance with some embodiments of the present disclosure.

[0038] Figures 17A-17D are flow charts of exemplary random access measurement indication processes at a UE, in accordance with some embodiments.

[0039] Figures 18A-18D are flow charts of exemplary random access measurement indication processes at a BS, in accordance with some embodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0040] Various exemplary embodiments of the invention are described below with reference to the accompanying figures to enable a person of ordinary skill in the art to make and use the invention. As would be apparent to those of ordinary skill in the art, after reading the present disclosure, various changes or modifications to the examples described herein can be made without departing from the scope of the invention. Thus, the present invention is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order or hierarchy of steps in the methods disclosed herein are merely exemplary approaches. Based upon design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be re-arranged while remaining within the scope of the present invention. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and the invention is not limited to the specific order or hierarchy presented unless expressly stated otherwise.

[0041] The discussion below may refer to functional entities or processes which are similar to those mentioned above with respect to conventional communication systems. As would be understood by persons of ordinary skill in the art, however, such conventional functional entities or processes do not perform the functions described below, and therefore, would need to be modified or specifically configured to perform one or more of the operations described below. Additionally, persons of skill in the art would be enabled to configure functional entities to perform the operations described herein after reading the present disclosure.

[0042] Figure 1 illustrates an exemplary wireless communication network 100 in which techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure. Such an exemplary network 100 includes a base station 102 (hereinafter "BS 102") and a user equipment device 104 (hereinafter "UE 104") that can communicate with each other via a communication link 1 10 (e.g., a wireless communication channel), and a cluster of notional cells 126, 130, 132, 134, 136, 138 and 140 overlaying a geographical area 101. As introduced above, the UE 104 may undergo a random access procedure to join the network 101. In Figure 1 , the BS 102 and UE 104 are contained within a respective geographic boundary of cell 126. Each of the other cells 130, 132, 134, 136, 138 and 140 may include at least one base station operating at its allocated bandwidth to provide adequate radio coverage to its intended users.

[0043] For example, the BS 102 may operate at an allocated channel transmission bandwidth to provide adequate coverage to the UE 104. The BS 102 and the UE 104 may communicate via a downlink radio frame 1 18, and an uplink radio frame 124 respectively. Each radio frame 1 18/124 may be further divided into sub-frames 120/127 which may include data symbols 122/128. In the present disclosure, the BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes," generally, which can practice the methods disclosed herein. Such communication nodes may be capable of wireless and/or wired communications, in accordance with various embodiments of the invention.

[0044] Figure 2 illustrates a block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM/OFDMA signals) in accordance with some embodiments of the invention. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one exemplary embodiment, system 200 can be used to transmit and receive data symbols in a wireless communication environment such as the wireless communication environment 100 of Figure 1 , as described above.

[0045] System 200 generally includes a base station 202 (hereinafter "BS 202") and a user equipment device 204 (hereinafter "UE 204"). The BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each module being coupled and interconnected with one another as necessary via a data communication bus 220. The UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each module being coupled and interconnected with one another as necessary via a data communication bus 240. The BS 202 communicates with the UE 204 via a communication channel 250, which can be any wireless channel or other medium known in the art suitable for transmission of data as described herein.

[0046] As would be understood by persons of ordinary skill in the art, system 200 may further include any number of modules other than the modules shown in Figure 2. Those skilled in the art will understand that the various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are described generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system. Those familiar with the concepts described herein may implement such functionality in a suitable manner for each particular application, but such implementation decisions should not be interpreted as limiting the scope of the present invention.

[0047] In accordance with some embodiments, the UE transceiver module 230 may be referred to herein as an "uplink" transceiver module 230 that includes a RF transmitter and receiver circuitry that are each coupled to the antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in time duplex fashion. Similarly, in accordance with some embodiments, the BS transceiver module 210 may be referred to herein as a "downlink" transceiver module 210 that includes RF transmitter and receiver circuity that are each coupled to the antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in time duplex fashion. The operations of the two transceiver modules 210 and 230 are coordinated in time such that the uplink receiver is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250 at the same time that the downlink transmitter is coupled to the downlink antenna 212. Preferably there is close time synchronization with only a minimal guard time between changes in duplex direction.

[0048] The UE transceiver module 230 and the BS transceiver module 210 are configured to communicate via the wireless data communication link 250, and cooperate with a suitably configured RF antenna arrangement 212/232 that can support a particular wireless communication protocol and modulation scheme. In some exemplary embodiments, the UE transceiver module 210 and the BS transceiver module 210 are configured to support industry standards such as the Long Term Evolution (LTE) and emerging 5G standards, and the like. It is understood, however, that the invention is not necessarily limited in application to a particular standard and associated protocols. Rather, the UE transceiver module 230 and the BS transceiver module 210 may be configured to support alternate, or additional, wireless data communication protocols, including future standards or variations thereof.

[0049] In accordance with various embodiments, the BS 202 may be an evolved node B (eNB), a serving eNB, a target eNB, a femto station, or a pico station, for example. In some embodiments, the UE 204 may be embodied in various types of user devices such as a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, laptop computer, wearable computing device, etc. The processor modules 214 and 236 may be implemented, or realized, with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration. [0050] Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in firmware, in a software module executed by processor modules 214 and 236, respectively, or in any practical combination thereof. The memory modules 216 and 234 may be realized as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to the transceiver modules 210 and 230, respectively, such that the transceiver modules 210 and 230 can read information from, and write information to, memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective transceiver modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by transceiver modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by the transceiver modules 210 and 230, respectively.

[0051] The network communication module 218 generally represents the hardware, software, firmware, processing logic, and/or other components of the base station 202 that enable bidirectional communication between the BS transceiver module 210 and other network components and communication nodes configured to communication with the base station 202. For example, network communication module 218 may be configured to support internet or WiMAX traffic. In a typical deployment, without limitation, network communication module 218 provides an 802.3 Ethernet interface such that the BS transceiver module 210 can communicate with a conventional Ethernet based computer network. In this manner, the network communication module 218 may include a physical interface for connection to the computer network (e.g., Mobile Switching Center (MSC)). The terms "configured for," "configured to" and conjugations thereof, as used herein with respect to a specified operation or function, refer to a device, component, circuit, structure, machine, signal, etc., that is physically or virtually constructed, programmed, formatted and/or arranged to perform the specified operation or function.

[0052] The present disclosure provides various embodiments of systems and methods for random access measurement indications. Random access measurement indications may include an indication from a UE that informs a network (e.g., a BS that the UE may communicate with to access the network) of results from the UE's measurements of signals broadcasted from the system for random access. In certain embodiments, these results may be indicated using an index, such as by transmitting an identifier of an index value that is mapped to signals broadcasted from the system for random access. As introduced above, a BS representing a network may broadcast signals such as a synchronization signal (SS), reference signal (RS), or broadcast channel (BCH) carrying system information (SI). The UE may perform measurements using these broadcast signals that may characterize how signals are being received at the UE. These characterizations may describe, for example, a signal strength for a beam used during a random access procedure, where a matching beam (e.g., a best beam) is a beam with a highest signal strength among beams received (e.g., signals broadcasted from the system for random access). In some embodiments, the results from these measurements may be conveyed by the selection of a subset of RACH resources or in MSG3.

[0053] In certain situations, the index of the matching measurement result may not be fully conveyed by the selection of a subset of RACH resources. As will be discussed further below, a matching measurement result may be a measurement result that best matches with a criteria, such as greatest signal strength or lowest noise. Accordingly, in various embodiments, a partial index may be conveyed during RACH resource selection (e.g., in MSGl ), while the full index (e.g., an index value that uniquely identifies the matching measurement result) is conveyed in MSG3.

[0054] Certain embodiments may be directed to various operations of the above referenced four message random access procedure or the two message random access procedures described above. For example, particular embodiments may be related to the fifth operation in the above referenced four message random access procedure or the two message random access procedures described above. As introduced above, the fifth operation may include selection of a RACH occasion belonging to a selected subset of RACH resources. Various embodiments may also be applicable to other variations of random access procedures.

[0055] As introduced above the UE may perform measurements on signals transmitted by the network (e.g., downlink (DL) signals that are broadcast by the network). In some embodiments, the UE performs measurements (and/or other analysis as discussed further in connection with operation 2 of the above referenced four or two message random access procedures) on signals broadcasted by the network (discussed further in connection with operation 1 of the above referenced four or two message random access procedures).

[0056] In some embodiments, the UE performs measurements on signals according to a UE- specific configuration. For example, certain UEs may perform certain types of measurements on random access DL signal that other UEs may not perform.

[0057] In various embodiments, the UE may perform multiple measurements on random access DL signals, resulting in multiple measurement results. Examples of measurement results include a reference signal (RS) received power (RSRP), RS received quality (RSRQ), signal to noise power ratio (SNR), signal to noise and interference power ratio (SINR) or other relevant metrics, in various embodiments.

[0058] Figure 3 is a block diagram 300 that illustrates a UE performing measurements on DL signals, in accordance with some embodiments. These measurements may produce measurement results (e.g., N measurement results). As mentioned above, the DL signals may be broadcasted in a predefined way, configured in broadcasted, multi-casted or uni-casted SI or configured in a UE-specific configuration, in various embodiments. As illustrated in Figure 3, DL signals 302 may be measured by a UE (e.g., UE measurements 304) to produce N measurement results 306.

[0059] Figure 4 is a block diagram 400 that illustrates DL signals, in accordance with some embodiments. The DL signals may be transmitted in synchronization signal (SS) bursts 402, SS blocks 406, and SS burst sets 408. An SS block 406 may contain DL signals on which a UE may perform one or more measurements. DL signals included in an SS block 406 include SSs (e.g., a primary SS (PSS) and a secondary SS (SSS)), and a Physical Broadcast Channel (PBCH). One or more SS blocks 406 may constitute an SS burst 402.

[0060] In some embodiments, the SS blocks 406 in an SS burst 402 may have the same structure (e.g., in time and frequency) whereas in other embodiments they may have different structures. In some embodiments, the SS blocks 406 in an SS burst 402 are consecutive, whereas in other embodiments they may be non-consecutive (e.g., there may be time intervals between some adjacent SS blocks 406 inside an SS bursts 402 between which there is no SS block 406). In such time intervals, for instance, downlink (DL) or uplink (UL) control signals may be transmitted. An SS burst set 408 may consist of a finite number of SS bursts 402. Also, SS burst sets 408 may be periodically transmitted in some embodiments. In certain embodiments, SS burst sets 408 may be transmitted aperiodically (e.g., on-demand or when the network can obtain access to the wireless channel in an unlicensed band).

[0061] As illustrated in Figure 4, an SS burst 402 consists of L SS blocks 406, where L is an arbitrary value. Also, an SS burst set 408 consists of one or more SS bursts 402 (e.g., J SS bursts 402, where J is an arbitrary value). In some embodiments, a UE performs measurements on the SS blocks 406 in an SS burst set 408 such that one measurement result per SS block is obtained (e.g., N=L*J, where N is the number of measurements). In some embodiments, one such measurement result is obtained through measurements on a single SS block 406 within an SS burst set 408. In some embodiments, one such measurement result is obtained from the same single SS block 406 within an SS burst set 408, (e.g. the n^th SS block), but measured over multiple SS burst sets 408. In some embodiments, a measurement from multiple SS burst sets 408 is performed from an SS block 406 in an SS burst set 408, but from different SS blocks 406 in different SS burst sets 408, for instance according to a predefined pattern. In some embodiments, this predefined pattern depends on the cell ID or cell identifier (e.g., an identity parameter of signals transmitted in SS blocks/bursts/burst sets).

[0062] In various embodiments, SS bursts 402 and/or SS burst sets 408 with multiple SS blocks 406 are used when a network node (e.g., a base station) uses beamforming for transmission of signals in an SS block 406. It may be beneficial to transmit a single or a small number of beams at the same time (e.g., to allow analog/hybrid beamforming implementation or to boost per-beam transmit power). In order to make signals in an SS block 406 reach the whole service area, it may be beneficial to use different transmit beams in different SS blocks 406. This could be implemented by what is sometimes called beam-sweeping, where the service area is swept by transmit beams used on the different SS blocks 406 in an SS burst 402 or SS burst set 408.

[0063] Figure 5 is a block diagram 400 that illustrates beamforming in an SS burst 502 and SS burst set 504, in accordance with some embodiments. In scenario (a), the same beam is used on all SS blocks 506 in an SS burst set 504, for example, an omni-directional beam. In scenario (b), the same beam is used on the SS blocks 506 in an SS burst 502, but different beams are used on different SS bursts 502 in an SS burst set 504. In scenario (b), beam repetition is used in the SS burst 502, but beam sweeping is used across the multiple SS bursts 502. In scenario (c), beam sweeping is used in an SS burst 502, with different beams used in different SS blocks 506 in the same SS burst 502. In this example, the beam sweeping is repeated in multiple SS bursts 502 within the SS burst set 504. In scenario (d), beam sweeping across the whole SS burst set 504 is used, with different beams used in different SS blocks 506 in an SS burst 502, but also different beams in different SS bursts 502.

[0064] In various embodiments, the beam sweeping as illustrated in Figure 5 is repeated in subsequent SS burst sets 504. In various embodiments, the beam sweeping sequence is permuted in subsequent SS burst sets 504. In some embodiments, the permutation is predefined. In some embodiments, the permutation is based on the system frame number in which the SS burst set 504 starts. In some embodiments, the permutation is based on a cell ID (e.g. an identity parameter of signals transmitted in SS blocks 506, SS bursts 502, and/or SS burst sets 504.

[0065] In various embodiments, N measurement result may correspond to different transmit beams. In some embodiment, a measurement result may be averaged using multiple SS blocks 506 which used the same beam (e.g., in the same SS burst 502 and/or the same SS burst set 504 and/or different SS burst sets 504). [0066] In various embodiments, multiple measurement results may be obtained from an SS block 506, In some embodiments, multiple reference signals (RSs) are transmitted in an SS block 506, on which a UE can perform multiple measurements. In some embodiments, multiple channel state information reference signals (CSI-RSs) (e.g. mobility RSs or beam RSs) are transmitted in an SS block 506, on which a UE can perform multiple measurements. In various embodiments, such RSs may be repeated in multiple SS blocks 506. Hence, in various embodiments, a UE may obtain multiple different measurement results from different SS blocks 506. For example, if K different RSs are transmitted in L SS blocks, then K*L different RSs may be transmitted in an SS burst 502, and a UE can obtain K*L measurement results in an SS burst 502.

[0067] In various embodiments, multiple measurement results may be obtained from signals not in an SS block 506. Such signals may, for instance, be UE-specifically configured (e.g. based on CSI-RS, beam RS, mobility RS) and may be transmitted more frequently than SS bursts 502 or SS burst sets 504, in some embodiments.

[0068] Measurement results may be indicated through selection of RACH resources in accordance with various embodiments. For example, a UE may select a subset of RACH resources based on multiple (e.g. N) measurement results. In various embodiments, a UE may select a subset of RACH resources based on which measurement results best match a particular criteria (e.g., matching measurement results that meet a definition of a best measurement result). The meaning of best (e.g., a definition of a matching measurement result) may be a highest or lowest value in accordance with the particular criteria. Stated another way, best may be a most extreme value. For example, a matching measurement result may indicate the highest measurement results, the lowest measurement result or another criterion in various embodiments. In the case of measured RSRP, the matching measurement result may be the highest RSRP in some embodiments. In various embodiments, a UE selects the subset of RACH resources based on which of the multiple measurement results is a matching measurement result (e.g., a most extreme, or best measurement result in accordance with (e.g., that match) a particular criteria, such as a highest or lowest measurement result value).

[0069] In some embodiments, the selection of RACH resources is such that the subset of RACH occasions is selected based on which measurement results match a particular criteria (e.g., a criteria that is a highest or a lowest value). For example, if multiple RSRP are measured on multiple different SS blocks, then a subset of RACH occasions may be selected based on in which SS block has the highest RSRP measured. In some embodiments, the value associated with a measurement result may not be indicated (e.g., the measured RSRP value) but rather only which measurement result matches a particular criteria (e.g., a criteria that is a highest or a lowest value).

[0070] In some embodiments, a subset of RACH occasions is selected based on a matching measurement result (e.g. a measurement result for a matching SS block that matches a particular criteria, such as a best value as a highest or lowest measured value). For example, a RACH occasion on which a preamble is detected may be selected to indicate the matching measurement result (e.g., the matching SS block with a best, or most extreme measurement result). In certain embodiments, the most extreme measurement result may be within a particular bounds, such as within a particular time period.

[0071] Figure 6 is a block diagram that illustrates how measurement results 602 may be mapped to (e.g., associated with) RACH occasions 604, in accordance with some embodiments. Stated another way, particular measurement results 602 that meet a particular criteria (e.g., matching measurement results, or measurement results that have a best or most extreme value) may be associated with (e.g., be used to identify or be identified by) a subset of RACH occasions 604, even in circumstances where subsets of RACH occasions 604 are disjoint. Accordingly, detection of a particular preamble, or particular RACH occasions 604, may indicate the matching measurement result 602 that best meets or matches with a particular criteria. The arrow illustrates an association between a measurement result 602 and a subset of RACH occasions 604.

[0072] Figure 7 is a block diagram that illustrates how SS blocks 702 may be associated with a subset of RACH occasions 704, in accordance with some embodiments. The matching SS block 702 that is associated with the matching measurement result may be used to select a subset of RACH occasions 704. Accordingly, a preamble in a subset of detected RACH occasions 704 can indicate which SS block is a matching SS block that is associated with the matching measurement result (e.g., a measurement result that best matches a particular criteria).

[0073] In some embodiments, the subset of RACH occasions may be selected based on matching SS blocks with matching measurement results (e.g., a measurement result that best matches a criteria). This matching SS block with matching measurement results may be indicated in a preamble on a RACH resource which partially indicates the matching SS block. A partial indication, discussed further below, means that the RACH occasion on which a preamble is detected indicates that the matching SS block is one of a subset of SS blocks, which is smaller than the set of all SS blocks.

[0074] Figure 8 is a block diagram that illustrates how multiple measurement results 802 may be mapped to (e.g., associated with) particular RACH occasions 804, in accordance with some embodiments. Stated another way, Figure 8 illustrates how matching measurement result may be mapped to (e.g., associated with) a subset of RACH occasions that are not disjoint. For example, if measurement result 0 is a matching measurement result (e.g., a measurement result that best matches a particular criteria, such as with a greatest or least value), then the UE may select RACH occasions 0 and RACH occasions 1 as a subset of RACH occasions. Here the term "RACH occasion x" means a set of RACH occasions, where the RACH occasions in "RACH occasion x" may not overlap with the RACH occasions in "RACH occasion y" if x is not equal to y. A preamble detected by a BS for RACH occasion 1 may not indicate which measurement result is the matching measurement result (e.g., because each RACH occasion is associated with multiple measurement results). However, the matching measurement result may be partially indicated (e.g., measurement results 0 or 1 may be determined to be the matching measurement result that best matches a particular criteria).

[0075] Figure 9 is a block diagram that illustrates an association between SS blocks 902 and RACH occasions 904, in accordance with some embodiments. Specifically, a matching SS block with matching measurement values that best match a particular criteria may be associated with a particular subset of RACH occasions, which have both adjoined and separated RACH occasions. Stated another way, the matching SS block with matching measurement results may be used to select (e.g., identify by association) a subset of RACH occasions, and vice versa. Accordingly, a preamble detected in a RACH occasion may partially indicate which SS block is the matching SS block with a measurement result that best matches a criteria. This may be because not all RACH occasions of the subset of RACH occasions 904 are identified with just a single RACH occasion. Also, preambles detected for a subset of RACH occasions 904 may indicate which SS block is the matching SS block with a measurement result that best matches a criteria. [0076] In some embodiments, the subset of RACH occasions selected based on the matching SS block (e.g., the SS block that with measurement results that best match a criteria) is such that a detected preamble on a RACH resource by the network may not partially indicate or identify the matching SS block. Stated another way, in certain embodiments, the RACH occasion on which a preamble is detected cannot be used to identify which of the SS blocks is the matching SS block, as will be discussed further below (e.g., in connection with Figure 10).

[0077] Figure 10 is a block diagram that illustrates an association between measurement results 1002 and RACH occasions 1004, in accordance with some embodiments. Specifically, measurement results may be associated with (e.g., used to select) a subset of RACH occasions, such that the RACH occasions completely overlap. Stated another way, each measurement result may be associated with the RACH occasions (e.g., the subset of RACH occasions) 0 to N-l . For example, if measurement result 0 is a matching measurement result, then the UE may select all RACH occasions 0 to N-l as subset of RACH occasions to indicate the matching measurement result. Accordingly, a preamble detected among, for example, RACH occasion 1 may not indicate which measurement result is the matching measurement result. Any of the N measurement results could have been the matching measurement result.

[0078] Figure 1 1 is a block diagram illustrating an association between SS blocks 1 102 and a subset of RACH occasions 1 104, in accordance with some embodiments. A matching SS block 1 102 associated with a matching measurement result may be used to select a subset of RACH occasions 1 104. Here, regardless of the measurement results of a particular SS block, all RACH occasions may be selected as a subset of RACH occasions. Hence, a specific preamble detected in a RACH occasion may not provide more information to indicate which SS block 1 102 is the matching SS block than any other preamble detected in a RACH occasion. Also, a particular SS block may be identified with a subset of RACH occasions that includes all RACH occasions.

[0079] Various embodiments of associations, such as those discussed above, may be conveyed to a UE in SI that is received by the UE (e.g., via broadcast, unicast, etc.). In some embodiments, the associations are conveyed to the UE in a UE-specific configuration. The different associations may be useful for different levels of transmit/receive beamforming reciprocity (e.g., at a BS). For example, the association illustrated in Figures 6 and 7 may be useful when the network side can exploit reciprocity. Specifically, the association illustrated in Figures 6 and 7 may be useful when the network uses the same or a similar beam for reception in the subset of RACH occasions as the transmit beam that was used for the DL signals. Similarly, that association may be useful when the network uses same or similar beams for reception in the subset of RACH occasions and for determining the corresponding measurement results (e.g., the matching measurement results) that are associated with the subset of RACH occasions.

[0080] When reciprocity cannot be exploited or only partially exploited (e.g. at a BS), then it may be more suitable to associate a certain measurement result with a subset of RACH occasions that overlaps with the subset of RACH occasions associated with other measurement results. This is illustrated for instance in Figures 8-1 1. In these embodiments, conveying only the RACH occasion in which a preamble is detected is not enough to indicate which measurement result was the matching measurement result. Stated another way for these embodiments, RACH resources (e.g., a RACH occasion or subset of RACH occasions) and either DL signals (e.g., SS blocks, SS bursts, or SS burst sets) or measurement results may not necessarily each be associated in a 1 : 1 relationship or unique identifying relationship. For example, each RACH occasion may be associated with multiple measurement results, and vice versa. Also, a single RACH occasion may not uniquely identify an SS block when an SS block is identified with a subset of RACH occasions that includes multiple RACH occasions.

[0081] In various embodiments, it may be beneficial to use the selection of a set of eligible preambles to indicate the matching measurement result (e.g., measurement result that best matches a particular criteria). Eligible preambles may refer to preambles that may be associated with RACH resources (as opposed to preambles which may be exclusively associated with resources other than RACH resources). For example, consider various embodiments where the RACH occasion in which a preamble is detected is not sufficient to deduce which measurement result was the matching measurement result. In such cases, different measurement results that are associated with overlapping sets of RACH occasions may be associated with different sets of eligible preambles.

[0082] For example, consider embodiments illustrated in Figure 8 and Figure 9, where the matching measurement results (e.g. a matching SS block in some embodiments) are partially indicated. When partially indicated, no single measurement result is indicated from a RACH resource (e.g., a RACH occasion). In some embodiments, the ambiguity of partial indication may be resolved by associating the different measurement results (e.g. different SS blocks in some embodiments) with disjoint sets of eligible preambles. In the example of a detected preamble among RACH occasion 1 in Figure 8, both measurement result 0 and 1 could have been the matching measurement result as inferred from RACH occasion 1. This may be resolved in various embodiments by associating measurement result 1 with the eligible preambles of RACH occasion 1 that are disjoint from (e.g., separate from) the corresponding set of preambles associated with measurement result 0. In a more specific example, preambles 0 to (Pi-1) could be associated with measurement result 0 and preambles Pi to (P₂-l) could be associated with measurement result 1. Hence, the matching measurement results may be indicated even though the RACH occasion only (e.g., identifying only the RACH occasion) does not provide a complete indication where a single measurement result is indicated from a single RACH resource in a 1 : 1 or unique identifying relationship).

[0083] Referring now to Figures 10 and 1 1 , the matching measurement result (e.g. the matching measurement results for an SS block that best matches a particular criteria) may not be indicated solely through the RACH occasion in certain embodiments. Similarly, by associating different measurement results with different disjoint sets of eligible preambles, an indicated preamble in a RACH occasion can still indicate the matching measurement result. For instance, if measurement result 1 is the matching measurement result, then a preamble from the set 0 to (Pi-1 ) may be selected. Also, if measurement result 2 is the matching measurement result, then a preamble from the set Pi to (P₂-l ) may be selected. Furthermore, if measurement result N is the matching measurement result, then a preamble from the set PN-I to (PN-1 ) may be selected.

[0084] In certain embodiments, associations between measurement results and RACH occasions may be combined with the associations to sets of eligible preambles. A RACH resource may be a combination of a RACH occasion and a set of eligible preambles. In various embodiments, a measurement result is associated with a subset of RACH resources (e.g. a subset of RACH occasions and a set of eligible preambles for each of those RACH occasions). In some embodiments, the set of eligible preambles may be the same for each RACH occasion in the subset. In some embodiments, a measurement result may be associated with different sets of eligible preambles in different RACH occasions in the subset of RACH occasions. Note that an association between a measurement result and a subset of RACH resources means that a UE may use a RACH resource in the subset of RACH resources (e.g., in the course of using all RACH resources in the subset of RACH resources) for preamble transmission if the measurement result is the matching measurement result that best matches a particular criteria.

[0085] In certain embodiments, in order to provide an indication of the matching measurement result (e.g. the matching SS block or the matching transmit beam with measurement results that best match particular criteria in some embodiments), a certain RACH occasion and preamble may not be associated with more than one measurement result. In other words, a measurement result that is the matching measurement result may be deduced from a detected preamble that is associated with a RACH occasion. This can be achieved, in various embodiments, by making sure that the different measurement results are associated with disjoint (e.g., different or separate) subsets of RACH resources. This means that a combination of a RACH occasion and preamble is in at most one subset of RACH resources.

[0086] Figure 12 is a block diagram that illustrates associations between measurement results 1202 and disjoint subsets of RACH resources 1204, in accordance with some embodiments. As illustrated, there could be N quantity of measurement results 1202. Given a number of RACH occasions and a number of preambles, the number of disjoint subsets of RACH resources M may be limited, in various embodiments. For instance, if there are L different subsets of RACH occasions and a total of P different eligible preambles in each of these subsets of RACH resources, then the number of disjoint subsets of RACH resources may be limited to M=L*P. In some embodiments, it may not be desirable to have a single eligible preamble in a set of eligible preambles, for instance if contention based random access is used. Furthermore, some preambles may be allocated to special purposes, such as contention free random access, which may reduce the total number of different eligible preambles P eligible for association with RACH resources. Hence, the number of disjoint subsets of RACH resources M may be smaller in embodiments with preambles allocated to special purposes than in embodiments without preambles allocated to special purposes.

[0087] Figure 13 is a block diagram that illustrates twelve disjoint subsets of RACH resources (e.g. M=12), in accordance with some embodiments. These subsets of RACH resources are constituted by four disjoint subsets of RACH occasions (e.g. L=4), in which there are three disjoint sets of eligible preambles (e.g. P=3), in this example.

[0088] Figure 14A is a block diagram 1402 that illustrates an embodiment of the four disjoint subsets of RACH occasions in Figure 13. Specifically, the block diagram 1402 illustrates how the subsets of RACH occasions are time-multiplexed.

[0089] Figure 14B is a block diagram 1404 that illustrates an embodiment of the four disjoint subsets of RACH occasions in Figure 13. Specifically, the block diagram 1404 illustrates how the subsets of RACH occasions are frequency-multiplexed.

[0090] Figure 14C is a block diagram 1406 that illustrates an embodiment of the four disjoint subsets of RACH occasions in Figure 13. Specifically, the block diagram 1406 illustrates how the subsets of RACH occasions are both time and frequency-multiplexed.

[0091] In various embodiments, measurement results may be indicated in MSG3. For example, the matching measurement result may not indicated tlirough the preamble, but instead in MSG3. In this case, the index of (e.g., identifier of) the matching measurement result may be explicitly included in MSG3 as a parameter. Accordingly, MSG3 may include an indicator that uniquely identifies the matching measurement result.

[0092] A disadvantage of indicating measurement results in MSG3 is that the matching measurement result cannot be used to improve preamble reception, for instance when reciprocity is available in the network (e.g., from a BS). Furthermore, the information in MSG3 may not be used to improve the communication performance of MSG2.

[0093] In various embodiments, measurement results may be indicted by a combination of RACH resource selections and MSG3. For example, the number of disjoint subsets of RACH resources may be configurable. In some cases, the amount of configuration may depend on the number of preambles allocated for other purposes, such as contention free random access, on- demand SI requests, positioning, scheduling requests, grant-free data transmission, and the like.

[0094] In certain embodiments, the number of disjoint subsets of RACH resources (M) may be larger than or equal to the number of measurement results (N) (e.g., the number of SS blocks in an SS burst or SS burst set). In such cases (M>N), it may be possible to associate measurement results with disjoint subsets of RACH resources. Stated another way, in such cases (M>N), a RACH resource may uniquely identify a measurement result (e.g., uniquely identify a measurement result that is a matching measurement result).

[0095] In particular embodiments, there may be more measurement results than disjoint subsets of RACH resources (e.g. M<N). In such cases, it may not be possible to fully and without ambiguity indicate a matching measurement result tlirough the selection of a subset of RACH resources. Various embodiments that address and/or remedy this deficiency are discussed further below. Also, in some embodiments, the subset of RACH resources (e.g., in MSG1) together with a parameter in MSG3 (e.g., an identifier in MSG3) may be utilized to convey information on a matching measurement result, as will be discussed further below.

[0096] In particular embodiments, a subset of RACH resources may be associated with a subset of measurement results, which may be smaller than the set of all measurement results. If the matching measurement result happens to be in the subset, then the selected subset of RACH resources may fully convey (e.g., be used to identify) the matching measurement result. Otherwise, in various embodiments, the UE may select one of the subsets of RACH resources, even though it is associated with a measurement result that is not the matching measurement result. This measurement result may be termed as an alternate selected measurement result that is not the matching measurement result. In certain embodiments, this alternate selected measurement result may be a measurement result that does not match a particular criteria as well as the matching measurement result. This may contrast with other embodiments where the UE may select a subset of RACH resources which is associated with a matching measurement result that best matches a particular criteria from among the measurement results which are associated with the M subsets of RACH resources.

[0097] In some embodiments, where different measurement results correspond to different transmitted and/or received beams, the UE may select a subset of RACH resources that is associated with a transmit and/or receive beam that has some similar properties as a matching beam. Such properties may include angles of arrival and departure, time of arrival, Doppler shift and spread or other quasi co-location (QCL) parameters, and the like. Beams with similar such properties may be termed as a beam group. In some embodiments, a UE may assume that MSG2 is transmitted by the network in the same way (e.g., on the same beam in some embodiments) as the signal generating the measurement result that was conveyed tlirough the selection of a subset of RACH resources (e.g. the signal associated with a matching measurement result or alternate selected measurement result).

[0098] Figure 15 is a block diagram that illustrates associations between measurement results 1502 and disjoint subsets of RACH resources 1504, in accordance with some embodiments. Specifically, Figure 15 illustrates how matching measurement results of N measurement results may not be fully conveyed (e.g., may not each be uniquely identified) through the selection of a subset of RACH resources. Instead, the UE may select one of M subsets of RACH resources (M<N), which are associated with N measurement results. For example, if measurement result N-2 is the matching measurement result, the UE may not fully indicate this (e.g., uniquely identify this) by any one of the M subsets of RACH resources. Stated another way, the measurement result N-2 may not be uniquely identified by, associated with, or mapped to a specific subset of RACH resources. Instead, the UE may select another subset of RACH resources for which the associated measurement result (e.g., measurement result N-l) may be uniquely identified as the alternate selected measurement result (introduced above). In certain embodiments, the alternate selected measurement result may be the closest (as measured by the criteria used to evaluate the matching measurement result) to the matching measurement result among the various measurement results.

[0099] In various embodiments where the measurement results correspond to beams, the UE may select a subset based on the associated measurement result/beam belonging to a beam group that has beneficial properties (e.g. strong signal, stable signal on multiple beams, etc!). In certain embodiments, if the UE selected the subset of RACH resources associated with measurement result N-l , then the UE may expect that the beam (or signal transmission scheme) used for the signal resulting in measurement result N-l will be used also for MSG2. Then the UE can adapt its receiver accordingly, such as to apply a suitable receive beam. Also, the UE can convey an index identifying the matching measurement result as N-l in MSG3. Alternatively, if the matching measurement result is measurement result N-2, the UE can convey an index identifying the matching result as measurement result N-2 in MSG3 (as opposed to identifying the matching measurement result as measurement result N-2 with a subset of RACH resources). In certain embodiments, if the matching measurement result is measurement result N-2, the UE can select measurement result N-l as an alternate selected measurement result for indication with a subset of RACH resources and then convey an index identifying the matching result as measurement result N-2 in MSG3 ,

[00100] In some embodiments, multiple measurement results may be associated with a subset of RACH resources. However, the UE may still select the subset of RACH resources for transmission based on the matching measurement result. Stated another way, to identify a matching measurement result, a UE may select a subset of RACH resources that identifies, or is otherwise associated with the matching measurement result. However, the best measurement result may not be fully conveyed (e.g., uniquely identified) by such a subset of RACH resources associated with multiple measurement results, since multiple measurement results may be associated with a given subset of RACH resources. As noted above, a UE that identifies a measurement result with a subset of RACH resources may assume that (e.g., be configured to receive) MSG2 based on the identified measurement result (e.g., using an associated or same transmission (Tx) beam). However, a UE that transmits a subset of RACH resources associated with multiple measurement results may assume that (e.g., be configured to receive) MSG2 in accordance with one of the associated multiple measurement results (e.g., using an associated or same Tx beam). For example, for MSG2, the UE may use a beam that combines the one or more beams used for the one or more of the signals associated with a measurement result identified by a subset of transmitted RACH resources. In some embodiments, the UE may assume (e.g., be configured to receive) multiple MSG2 transmissions where the different MSG2 transmissions are associated at least one measurement result identified by a subset of transmitted RACH resources. In some embodiments, the UE may assume an open loop transmission scheme assuming transmissions/beams according to the signals associated with the subset of transmitted RACH resources, for example using precoder cycling or open loop spatial multiplexing with transmission rank 1. In various embodiments where measurement results correspond to beams, the beams associated with a subset of RACH resources may form a beam group.

[00101] Figure 16 is a block diagram that illustrates associations between multiple measurement results 1602 and disjoint subsets of RACH resources 1604, in accordance with some embodiments. In various embodiments, the subset of RACH resources is selected as m = n_best MOD M, where MOD is the modulo operator ("remainder after division"), m (belongs to {0, M- l } ) is the index of the selected subset of RACH resources, n_best (belongs to {0, N- 1 } ) is the index of the matching measurement result, and M is the number of subsets of RACH resources. In various embodiments, the UE includes the parameter m_msg3 = n_best DIV M in MSG3, where DIV represents integer division.

[00102] Examples of data structures (e.g., tables) that relate respective indexes for matching measurements, RACH resources, and MSG 3 are provided below with Table 1 and Table 2:

0 0 0

1 0 1

2 1 0

3 1 1

4 2 0

5 2 1

6 3 0

7 3 1

Table 2

[00103] Table 1 and Table 2 illustrate different embodiments where a matching measurement result is partially indicated in the selection of a subset of RACH resources and partially in MSG3. In the examples of Table 1 and Table 2, N=8 and =4. In various embodiments where the matching measurement result may be partially indicated through the selection of a subset of RACH resources, the full index of the matching measurement result (e.g., an index value that uniquely identifies the matching measurement result) may be included as a parameter in MSG3. [00104] Figure 17A illustrates a flow chart of an exemplary random access measurement indication process 1700, in accordance with some embodiments. The random access measurement indication process 1700 may be perfonned by a UE, as discussed above. It is noted that the process 1700 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1700 of Figure 17A, certain operations may be omitted, certain operations may be perfonned concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1700, M>N, so the selected subset of RACH resources can fully convey (e.g., uniquely identify) the matching measurement result that best matches with a particular criteria. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. [00105] At block 1702, a UE may perform measurements on DL signals to obtain N measurement results. At block 1704, the UE may determine a matching measurement result that best matches a particular criteria. At block 1706, the UE may select a subset of RACH resources based on the matching measurement result that best matches a particular criteria. At block 1708, the UE may receive a MSG2 that is transmitted based on the DL signal associated with the matching measurement result (e.g., the selected subset of RACH resources).

[00106] Figure 17B illustrates a flow chart of an exemplary random access measurement indication process 1720, in accordance with some embodiments. The random access measurement indication process 1720 may be performed by a UE, as discussed above. It is noted that the process 1720 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1720 of Figure 17B, certain operations may be omitted, certain operations may be performed concuiTently with other operations, and that some other operations may only be briefly described herein. For the process 1720, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of RACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. At block 1722, a UE may perform measurements on DL signals to obtain N measurement results.

[00107] At block 1724, the UE may determine an overall best matching measurement result that overall best matches a particular criteria with an association. The overall best matching measurement result may be the matching measurement result or may be a measurement result that is similar or closest to the matching measurement result as evaluated by the same criteria used to determine the matching measurement result. Stated another way, the overall best matching measurement result may be an alternate selected measurement result, as discussed further above.

[00108] At block 1726, the UE may select a subset of RACH resources based on the overall best matching measurement result. In certain embodiments, the UE may select a subset of RACH resources based on the alternate selected measurement result.

[00109] At block 1728, the UE may receive a MSG2 that is transmitted based on the DL signal associated with the overall best matching measurement result. In certain embodiments, the UE may receive a MSG2 that is transmitted based on the DL signal associated with the alternate selected measurement result (which is the overall best matching measurement result).

[00110] At block 1730, the UE may transmit a MSG3 that fully indicates (e.g., uniquely identifies) the matching measurement result. The matching measurement result may also be referred to as the best overall measurement result.

[00111] Figure 17C illustrates a flow chart of an exemplary random access measurement indication process 1740, in accordance with some embodiments. The random access measurement indication process 1740 may be performed by a UE, as discussed above. It is noted that the process 1740 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1740 of Figure 17C, certain operations may be omitted, certain operations may be performed concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1740, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of RACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results.

[00112] At block 1742, a UE may perform measurements on DL signals to obtain N measurement results. At block 1744, the UE may determine a matching measurement result that best matches a particular criteria. At block 1746, the UE may select a subset of RACH resources based on the matching measurement result. At block 1748, the UE may receive a MSG2 that is transmitted based on the DL signal(s) corresponding to (e.g., associated with) the selected subset of RACH resources. In certain embodiments, as discussed above, multiple DL signals may be associated with a selected subset of RACH resources. At block 1750, the UE may transmit a MSG3 that fully indicates (e.g., uniquely identifies) the matching measurement result (e.g., the best overall measurement result).

[00113] Figure 17D illustrates a flow chart of an exemplary random access measurement indication process 1760, in accordance with some embodiments. The random access measurement indication process 1760 may be performed by a UE, as discussed above. It is noted that the process 1760 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1760 of Figure 17D, certain operations may be omitted, certain operations may be performed concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1760, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of ACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results.

[00114] At block 1762, a UE may perform measurements on DL signals to obtain N measurement results. At block 1764, the UE may determine a matching measurement result that best matches a particular criteria.

[00115] At block 1766, the UE may select a subset of RACH resources based on the matching measurement result. The selection may be made where m=n_best MOD M, as discussed further above.

[00116] At block 1768, the UE may receive a MSG2 that is transmitted based on the DL signal(s) corresponding to (e.g., associated with) the selected subset of RACH resources (e.g., subset m), discussed further above. In certain embodiments, as discussed above, multiple DL signals may be associated with a selected subset m of of RACH resources.

[00117] At block 1770, the UE may transmit a MSG3 that fully indicates (e.g., uniquely identifies) the matching measurement result (e.g., the best measurement result). This matching measurement result may be identified as m_msg3=n_best DIV M, as discussed further above.

[00118] Figure 18A illustrates a flow chart of an exemplary random access measurement indication process 1800, in accordance with some embodiments. The random access measurement indication process 1800 may be performed by a BS, as discussed above. It is noted that the process 1800 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1800 of Figure 18A, certain operations may be omitted, certain operations may be performed concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1800, M>N, so the selected subset of RACH resources can fully convey (e.g., uniquely identify) the matching measurement result that best matches with a particular criteria. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. Also, process 1800 may be a counterpart process to process 1700 of Figure 17A.

[00119] Returning to Figure 18A, at block 1802, a BS may coordinate random access with a UE. This coordination may include a preprogrammed setting at each of the BS and UE and/or communication between the UE that ensures that the BS and UE may communicate under a same standard for communication (e.g., so that they may engage in random access). For example, the standard may include an understanding of what kinds of signals may be passed between the UE and BS, types of associations between data, the subsets of RACH resources, and the like.

[00120] At block 1804, the BS may transmit DL signals. A UE may be configured to obtain measurement results (e.g., N measurement results) from these DL signals.

[00121] At block 1806, the BS may detect a preamble in a subset of RACH resources. These RACH resources may be transmitted from the UE that received the DL signals.

[00122] At block 1808, the BS may deduce which DL signal the UE determined to have a matching measurement result that best matches a particular criteria. The DL signal may also be termed as a matching DL signal, from where a matching measurement result was determined.

[00123] At block 1810, the BS may transmit a MSG2 in the same way (e.g., with a same beam) as the matching DL signal, from where a matching measurement result was determined that best matches a particular criteria.

[00124] Figure 18B illustrates a flow chart of an exemplary random access measurement indication process 1820, in accordance with some embodiments. The random access measurement indication process 1820 may be performed by a BS, as discussed above. It is noted that the process 1820 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1820 of Figure 18B, certain operations may be omitted, certain operations may be performed concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1820, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of RACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. Also, process 1820 may be a counterpart process to process 1720 of Figure 17B.

[00125] Returning to Figure 18B, at block 1822, a BS may coordinate random access with a UE. This coordination may include a preprogrammed setting at each of the BS and UE and/or communication between the UE that ensures that the BS and UE may communicate under a same standard for communication. For example, the standard may include an understanding of what kinds of signals may be passed between the UE and BS, types of associations between data, the subsets of RACH resources, and the like.

[00126] At block 1824, the BS may transmit DL signals. A UE may be configured to obtain measurement results (e.g., N measurement results) from these DL signals.

[00127] At block 1826, the BS may detect a preamble in a subset of RACH resources. These RACH resources may be transmitted from the UE that received the DL signals. [00128] At block 1828, the BS may deduce which DL signal the UE determined to have a best matching measurement result with association that best matches a particular criteria at the UE. This best matching measurement result with association may be the overall best measurement result, or the alternate selected measurement result, as discussed further above. In certain embodiments, the best matching measurement result with association may be the matching measurement result or may be a measurement result that is similar or closest to the matching measurement result as evaluated by the same criteria used to determine the matching measurement result.

[00129] At block 1830, the BS may transmit a MSG2 in the same way (e.g., with a same beam) as the deduced DL signal that corresponds to (e.g., is associated with) the best matching measurement result with association. At block 1832, the BS may receive a MSG3 that informs of (e.g., uniquely identifies) the matching measurement result (e.g., the best overall measurement result).

[00130] Figure 18C illustrates a flow chart of an exemplary random access measurement indication process 1840, in accordance with some embodiments. The random access measurement indication process 1840 may be perfonned by a BS, as discussed above. It is noted that the process 1840 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1840 of Figure 18C, certain operations may be omitted, certain operations may be perfonned concurrently with other operations, and that some other operations may only be briefly described herein. For the process 1840, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of RACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. Also, process 1840 may be a counterpart process performed at a BS to process 1740 of Figure 17C performed at a UE.

[00131] Returning to Figure 18C, at block 1842, a BS may coordinate random access with a UE. This coordination may include a preprogrammed setting at each of the BS and UE and/or communication between the UE that ensures that the BS and UE may communicate under a same standard for communication. For example, the standard may include an understanding of what kinds of signals may be passed between the UE and BS, types of associations between data, the subsets of RACH resources, and the like.

[00132] At block 1844, the BS may transmit DL signals. A UE may be configured to obtain measurement results (e.g., N measurement results) from these DL signals.

[00133] At block 1846, the BS may detect a preamble in a subset of RACH resources. These

RACH resources may be transmitted from the UE that received the DL signals.

[00134] At block 1848, the BS may deduce multiple DL signals, of which one provided a matching measurement result (e.g., measurement result that best matches a criteria) at the UE.

[00135] At block 1850, the BS may transmit a MSG2 in the same way as one or multiple of the deduced multiple DL signals of block 1848. Stated another way, the BS may transmit MSG2 once or multiple times, in a same manner as one or more of the multiple DL signals (or a combination of multiple DL signals) deduced in block 1848.

[00136] At block 1852, the BS may receive a MSG3 that informs of (e.g., uniquely identifies) the matching measurement result (e.g., the best overall measurement result): [00137] Figure 18D illustrates a flow chart of an exemplary random access measurement indication process 1860, in accordance with some embodiments. The random access measurement indication process 1860 may be performed by a BS, as discussed above. It is noted that the process 1860 is merely an example, and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the process 1860 of Figure 18D, certain operations may be omitted, certain operations may be performed concuiTently with other operations, and that some other operations may only be briefly described herein. For the process 1860, M<N, so the selected subset of RACH resources cannot fully convey (e.g., uniquely identify) the matching measurement result that best matches a particular criteria. Instead, the matching measurement result is partly conveyed through the selection of a subset of RACH resources, and fully conveyed (e.g., uniquely identified) through MSG3. As noted above, M refers to the number of disjoint subsets of RACH resources, and N refers to the number of measurement results. Also, process 1860 may be a counterpart process performed at a BS to process 1760 of Figure 17D performed at a UE.

[00138] Returning to Figure 18D, at block 1862, a BS may coordinate random access with a UE. This coordination may include a preprogrammed setting at each of the BS and UE and/or communication between the UE that ensures that the BS and UE may communicate under a same standard for communication. For example, the standard may include an understanding of what kinds of signals may be passed between the UE and BS, types of associations between data, the subsets of RACH resources, and the like.

[00139] At block 1864, the BS may transmit DL signals. A UE may be configured to obtain measurement results (e.g., N measurement results) from these DL signals. [00140] At block 1866, the BS may detect a preamble in a subset of RACH resources. These RACH resources may be transmitted from the UE that received the DL signals.

[00141] At block 1868, the BS may deduce multiple DL signals, of which one provided a matching measurement result (e.g., a measurement result that best matches a criteria) at the UE. This deduction may be based on the subset m, which is the received subset of RACH resources. The multiple DL signals may each fulfil m=n MOD M, discussed further above in connection with Figure 16.

[00142J At block 1870, the BS may transmit a MSG2 in the same way as one or multiple of the deduced multiple DL signals of block 1868. Stated another way, the BS may transmit MSG2 once or multiple times, in a same manner as one or more of the multiple DL signals (or a combination of multiple DL signals) deduced in block 1868.

[00143] At block 1872, the BS may receive a MSG3 that informs of (e.g., uniquely identifies) the matching measurement result (e.g., the best overall measurement result). Stated another way, the BS may receive m_MSG3, from which the BS may construct n_best=m_MSG3*M+m, discussed further above in connection with Figure 16.

[00144] While various embodiments of the invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Likewise, the various diagrams may depict an example architectural or configuration, which are provided to enable persons of ordinary skill in the art to understand exemplary features and functions of the invention. Such persons would understand, however, that the invention is not restricted to the illustrated example architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, as would be understood by persons of ordinary skill in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

[00145] It is also understood that any reference to an element herein using a designation such as "first," "second," and so forth does not generally limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must precede the second element in some manner.

[00146] Additionally, a person having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits and symbols, for example, which may be referenced in the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[00147] A person of ordinary skill in the art would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two), firmware, various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as "software" or a "software module), or any combination of these techniques. To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure.

[00148] Furthermore, a person of ordinary skill in the art would understand that various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[00149] If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[00150] In this document, the term "module" as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purpose of discussion, the various modules are described as discrete modules; however, as would be apparent to one of ordinary skill in the art, two or more modules may be combined to form a single module that performs the associated functions according embodiments of the invention.

[00151] Additionally, one or more of the functions described in this document may be performed by means of computer program code that is stored in a "computer program product", "computer-readable medium", and the like, which is used herein to generally refer to media such as, memory storage devices, or storage unit. These, and other forms of computer-readable media, may be involved in storing one or more instructions for use by processor to cause the processor to perform specified operations. Such instructions, generally referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings), which when executed, enable the computing system to perform the desired operations.

[00152] Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the invention. It will be appreciated that, for clarity purposes, the above description has described embodiments of the invention with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the invention. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Hence, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[00153] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as recited in the claims below.

Claims

CLAIMS What is claimed is:

1. A method performed by a first communication node, the method comprising:

obtaining measurement results from a plurality of signals;

determining a matching measurement result of the measurement results that corresponds to a matching signal of the plurality of signals, wherein the matching measurement result best matches with a criteria;

determining random access channel (RACH) resources based on the matching signal; sending a first message using the RACH resources; and

receiving a second message based on the matching signal.

2. The method of claim 1 , wherein the RACH resources identify the matching signal.

3. The method of claim 1 , wherein the RACH resources partially identify the matching signal.

4. The method of claim 3, comprising:

sending an identifier that uniquely identifies the matching signal.

5. The method of claim 1 , wherein the criteria is one of: a greatest reference signal received power (RSRP), a greatest reference signal received quality (RSRQ), and a greatest signal to noise and interference power ratio (SINR).

6. The method of claim 1 , wherein the plurality of signals are at least one of a synchronization signal (SS) block, SS bursts, and SS burst sets.

7. The method of claim 1 , wherein the first communication node is a user equipment (UE).

8. A method performed by a first communication node, the method comprising:

transmitting a plurality of signals; receiving a first message on a plurality of random access channel (RACH) resources; determining a matching signal of the plurality of signals based on the RACH resources; and

transmitting a second message based on the matching signal.

9. The method of claim 8, further comprising:

receiving an identifier that uniquely identifies the matching signal.

10. The method of claim 8, wherein the matching signal is associated with a matching measurement result for the matching signal, wherein the matching measurement result best matches with a criteria.

11. The method of claim 8, wherein the RACH resources identify the matching signal.

12. The method of claim 8, wherein the RACH resources partially identify the matching signal.

13. The method of claim 8, wherein the first communication node is a base station (BS).

14. An apparatus, comprising:

a transceiver configured to:

receive a plurality of signals; and

at least one processor configured to:

obtain measurement results from the plurality of signals,

determine a matching measurement result of the measurement results that corresponds to a matching signal of the plurality of signals, wherein the matching measurement result best matches with a criteria,

determine random access channel (RACH) resources based on the matching signal,

send, using the transceiver, a first message using the RACH resources, and receive, using the transceiver, a second message based on the matching signal.

15. The apparatus of claim 14, wherein the RACH resources identify the matching signal.

16. The apparatus of claim 14, wherein the RACH resources partially identify the matching signal.

17. The apparatus of claim 16, wherein the at least one processor is configured to send, using the transceiver, an identifier that uniquely identifies the matching signal.

18. The apparatus of claim 14, wherein the criteria is one of: a greatest reference signal received power (RSRP), a greatest reference signal received quality (RSRQ), and a greatest signal to noise and interference power ratio (SINR).

19. An apparatus, comprising:

a transceiver configured to:

transmit a plurality of signals, and

receive a first message on a plurality of random access channel (RACH) resources; and

a processor configured to:

determine a matching signal of the plurality of signals based on the RACH resources; and

transmit, using the transceiver, a second message based on the matching signal.

20. The apparatus of claim 19, wherein the transceiver is configured to receive, using the transceiver, an identifier that uniquely identifies the matching signal.

21. The apparatus of claim 19, wherein the matching signal is associated with a matching measurement result for the matching signal, wherein the matching measurement result best matches with a criteria.

22. The apparatus of claim 19, wherein the RACH resources identify the matching signal. The apparatus of claim 19, wherein the RACH resources partially identify the matching