Method and apparatus for selecting antenna ports using received antenna port specific adjustments

Abstract

The invention relates to a method and apparatus for selecting an antenna port using received antenna port specific adjustments. A method and apparatus is provided in which one or more reference signals in a wireless communication network are received. A value for each of one or more measurable characteristics with respect to each of the received reference signals is determined. At least one reference signal is selected based on a comparison of the resulting values of the measurable characteristics of the received reference signals and based on availability of dedicated contention-free random access channel resources, wherein the dedicated contention-free random access channel resources are resources dedicated for use by a particular user equipment utilizing a random access channel, the dedicated contention-free random access channel resources being associated with the selected at least one reference signal.

Description

[0001] This application is a divisional application of PCT application number PCT / IB2018 / 001042, which entered the Chinese national phase on February 6, 2020; international application date August 9, 2018; Chinese application number 201880051172.8; and invention title "Method and apparatus for specifically adjusting and selecting an antenna port using a received antenna port". Technical Field

[0002] This disclosure relates to a method and apparatus for beam selection and random access in multi-beam operation, and more specifically, to a method and apparatus for receiving antenna port-specific values ​​from a network for making antenna port-specific adjustments that affect the operation and / or decisions made by user equipment relative to different antenna ports. Background Technology

[0003] Currently, user equipment (UEs), such as wireless communication devices, use wireless signals within a network environment to communicate with other communication devices. This network environment may include one or more cells, within which various communication connections with the network and other devices operating within the network can be supported. Network environments often involve one or more sets of standards, each defining aspects of any communication connection made when the corresponding standard is used within the network environment. Examples of standards under development and / or existing standards include New Radio Access Technology (NR), Long Term Evolution (LTE), Universal Mobile Telecommunications Service (UMTS), Global System for Mobile Communications (GSM), and / or Enhanced Data GSM Environment (EDGE).

[0004] At any given time, the conditions associated with establishing and maintaining a communication connection between a wireless communication device and a network via a specific cell can vary, depending on which cell and / or antenna port is used to support the connection. These conditions may change over time, where the ability to communicate may depend on the movement of the wireless communication device relative to the coverage area associated with each cell / antenna port, and the potential impact on any other communication attempts by other devices transmitting wirelessly near the wireless communication device at the same or similar frequencies, either as part of the network or isolated from it. In some cases, the conditions that may need to be considered may be environment-wide, isolated from the network but detectable by it. In other cases, the conditions that may need to be considered may be network-specific. In any case, the network may be aware of potentially helpful factors to consider in determining the optimal way for the wireless communication device to establish or maintain a communication connection with the network.

[0005] The inventors have recognized that transmitting specific parameters of the downlink transmit antenna port can be helpful for a network, and these specific parameters can be used to provide offset or adjustment values ​​that can be used by wireless communication devices to influence and / or better guide the operation of wireless communication devices within the network. Summary of the Invention

[0006] Currently, user equipment, such as wireless communication devices, uses wireless signals to communicate with other communication devices. According to a possible embodiment, a method is provided in the user equipment. The method includes receiving a respective reference signal associated with each of one or more downlink transmit antenna ports in a wireless communication network. Determining values ​​for each of one or more measurable characteristics associated with each of the received reference signals or each of the received reference signals. Receiving one or more parameters, the parameters including one or more adjustments, wherein each adjustment is specific to one of the downlink transmit antenna ports, and including adjustments in the form of one or more respective offset values ​​to be applied to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals. The method further includes selecting at least one downlink transmit antenna port as a serving downlink transmit antenna port for the user equipment based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjustments have been applied to the corresponding determined values.

[0007] According to another possible embodiment, a user equipment is provided. The user equipment includes a transceiver that receives a respective reference signal associated with each of one or more downlink transmit antenna ports in a wireless communication network. The user equipment also includes a controller that determines values ​​for each of one or more measurable characteristics associated with each of the received reference signals or with each of the received reference signals. The transceiver also receives one or more parameters including one or more adjustments, each adjustment specific to one of the downlink transmit antenna ports, and including adjustments in the form of one or more respective offset values ​​to be applied to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals. The controller further selects at least one downlink transmit antenna port to be used as a serving downlink transmit antenna port for the user equipment based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjustments have been applied to the corresponding determined values.

[0008] According to another possible embodiment, a method in a network entity is provided. The method includes transmitting a respective reference signal via each of one or more downlink transmit antenna ports, the reference signal being received by one or more user equipments, and determining values ​​for each of one or more measurable characteristics relative to or associated with each of the received reference signals. The method in the network entity further includes determining one or more parameters that can then be transmitted to the one or more user equipments, the parameters including one or more adjustments, wherein each adjustment is specific to one of the downlink transmit antenna ports, and includes adjustments in the form of one or more respective offset values ​​to be applied by the user equipment to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals, and selecting at least one downlink transmit antenna port from which the user equipment will use as a serving downlink transmit antenna port for the user equipment based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjustments have been applied to the corresponding determined values.

[0009] According to another possible embodiment, a network entity is provided. The network entity includes a transceiver that transmits a respective reference signal via each of one or more downlink transmit antenna ports, the reference signal being received by one or more user equipments, which can determine values ​​for each of one or more measurable characteristics relative to or associated with each of the received reference signals. The network entity also includes a controller that determines one or more parameters, the one or more parameters including one or more adjustments, each adjustment specific to one of the downlink transmit antenna ports, and including adjustments in the form of one or more respective offset values ​​applied by the user equipment to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals. Based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjustments have been applied to the corresponding determined values, the user equipment selects at least one downlink transmit antenna port from which it will be used as a serving downlink transmit antenna port for the user equipment.

[0010] These and other objects, features, and advantages of this application will become apparent from the accompanying drawings and the description of one or more preferred embodiments. Attached Figure Description

[0011] Figure 1 This is a block diagram of an exemplary network environment in which the present invention is suitable for operation.

[0012] Figure 2It is a plan view of the respective transmit beams for each of the exemplary base stations and user equipment, each transmit beam being associated with one of a pair of service synchronization signal blocks for a random access channel;

[0013] Figure 3 This is a flowchart for providing beam selection in user equipment using downlink transmit antenna port-specific adjustments;

[0014] Figure 4 This is a flowchart for providing downlink transmit antenna port-specific adjustments for beam selection to one or more user equipment by a network entity;

[0015] Figure 5 It is a flowchart for determining the preamble transmit power adjustment value used by a user equipment during random access based on downlink transmit antenna port specific parameters received from a network entity;

[0016] Figure 6 This is a flowchart for a network entity to provide downlink transmit antenna port-specific parameters to one or more user equipments to determine the preamble transmit power adjustment value; and

[0017] Figure 7 This is an example block diagram of an apparatus according to a possible embodiment. Detailed Implementation

[0018] While this disclosure allows for various forms of embodiments, preferred embodiments are shown in the drawings and will be described below, in order to be understood that this disclosure will be considered as illustrative of the invention and not intended to limit the invention to the specific embodiments illustrated.

[0019] The embodiments provide methods and apparatus for beam selection and random access in multi-beam operation.

[0020] Figure 1 This is an example block diagram of system 100 according to a possible embodiment. System 100 may include wireless communication device 110 (such as user equipment (UE)), base station 120 (such as enhanced Node B (eNB) or next-generation Node B (gNB)) and network 130. Wireless communication device 110 may be a wireless terminal, portable wireless communication device, smartphone, cellular phone, flip phone, personal digital assistant, personal computer, selective call receiver, tablet computer, laptop computer, or any other device capable of transmitting and receiving communication signals on a wireless network.

[0021] Network 130 may include any type of network capable of transmitting and receiving wireless communication signals. For example, network 130 may include wireless communication networks, cellular telephone networks, time division multiple access (TDMA) based networks, code division multiple access (CDMA) based networks, orthogonal frequency division multiple access (OFDMA) based networks, long-term evolution (LTE) networks, 5G networks, 3rd generation partnership (3GPP) based networks, satellite communication networks, high-altitude platform networks, the Internet and / or other communication networks.

[0022] In fifth-generation (5G) new radio access technology (RAT) that supports single-beam and multi-beam operation, a user equipment (UE) can evaluate the quality of one or more downlink (DL) transmit (Tx) beams by performing measurements on synchronization signal (SS) blocks and / or channel state information reference signals (CSI-RS), where an antenna port of a given SS block or a given CSI-RS port is associated with a DL Tx beam. When the UE is in idle mode or performing an initial access procedure, the UE can derive cell quality values ​​based on one or more SS block measurements and (re)select the cell to camp on. Furthermore, the UE can select a serving SS block (i.e., serving beam) from one or more received SS blocks of the selected cell. For example, an SS block with the maximum SS block reference signal received power (SS block - RSRP) value can be selected as the serving SS block. When the UE is in connected mode, in addition to SS blocks, the UE can also perform measurements on the CSI-RS and can report one or more selected CSI-RS resources / ports and / or SS blocks. If a network entity (NE) configures the association between DL signals / channels such as SS blocks and CSI-RS and subsets of random access channel (RACH) resources (i.e., time and frequency resources) and / or subsets of RACH preamble indices, a user equipment can implicitly indicate a selected DL Tx beam (i.e., SS block or CSI-RS resource / port) by transmitting a random access channel (RACH) preamble on the RACH resource associated with the selected SS block or CSI-RS port.

[0023] When selecting a serving SS block or CSI-RS resource / port, the SS block or CSI-RS resource / port with the highest received RSRP may not always be the optimal choice for the user equipment (UE) in terms of random access latency and system capacity. For example, during handover, the UE may prefer an SS block or CSI-RS resource / port that allows for fast RACH completion. Therefore, the UE should be able to flexibly select the appropriate SS block or CSI-RS resource / port based on the scenario without causing too much interference.

[0024] This disclosure discloses a method relating to the (re)selection of the SS block or CSI-RS resource / port and the RACH preamble power setting when the serving SS block or CSI-RS resource / port is changed during the RACH process.

[0025] At least some existing proposals discuss methods for performing power increases when a User Equipment (UE) changes its UE Tx beam for a given serving DL Tx antenna port. More specifically, they propose limiting the number of UE Tx beam changes used for RACH preamble (re)transmissions at each power increase level. Because each UE can have different antenna / beamforming capabilities and architectures, and because UEs can perform random access before reporting UE capability information, the question of how to transmit the preamble within the maximum allowed number of preamble transmissions, such as whether to change the UE Tx beam, is best left to the UE to implement. Furthermore, the aforementioned existing proposals do not address how to set the preamble Tx power when a UE changes its serving DL Tx antenna port.

[0026] SS Block / CSI-RS Port Selection / Reselection

[0027] According to possible embodiments, for single-beam or multi-beam network operations, a network entity can configure one or more DL Tx antenna ports on which user equipment can perform measurements. In one embodiment, each DL Tx antenna port is associated with a DL Tx beam. In one example, a DL Tx antenna port is an antenna port of an SS block. In another example, a DL Tx antenna port is an antenna port of a CSI-RS resource. In one example, some DL Tx antenna ports may correspond to antenna ports of a single CSI-RS resource or antenna ports of different CSI-RS resources.

[0028] Define an antenna port such that the channel transmitting a symbol on the same antenna port can be inferred from the channel transmitting another symbol on that antenna port.

[0029] If the large-scale characteristics of a channel transmitting symbols on one antenna port can be inferred from the channel transmitting symbols on another antenna port, then the two antenna ports can be said to be quasi-co-located. Large-scale characteristics include delay spread, Doppler spread, Doppler shift, average gain, average delay, and one or more spatial reception (Rx) parameters such as angular spread, angle of arrival, angle of deviation, and spatial correlation of the receiver antenna. The two antenna ports can be quasi-co-located relative to a subset of these large-scale characteristics.

[0030] An SS block may include a primary synchronization signal and / or a secondary synchronization signal. In one example, an SS block may include a PBCH (Physical Broadcast Channel) with an associated PBCH reference signal, and the SS block may also be referred to as an SS / PBCH block. In one example, the user equipment may assume that the same antenna port can be used for the transmission of the primary synchronization signal, the secondary synchronization signal, and the PBCH.

[0031] In an alternative embodiment, a (DL Tx) antenna port may be associated with one or more SS blocks, each SS block having a corresponding SS block index. An antenna port associated with a first SS block (having a first SS block index) may correspond to a first DLTx beam (beamforming pattern), and an antenna port associated with a second SS block (having a second SS block index) may correspond to a second DL Tx beam. Therefore, depending on the SS block, the antenna port may correspond to different DL TX beams, i.e., the first DLTx beam or the second DL TX beam. The first DL Tx beam may be different from the second DL TX beam. The first SS block may be different from the second SS block, which may result in the first SS block index being different from the second SS block index. In one example, the first SS block may be transmitted at a first time instance, and the second SS block may be transmitted at a second time instance. In another example, the first and second SS block transmission instances may overlap, and in some examples, they may completely overlap. In one example, the user equipment may assume that any transmission instance of an SS block with the same SS block index is transmitted on the same antenna port. User equipment may not assume that a channel transmitting a first SS block with a first SS block index can be inferred from a channel transmitting a second SS block with a second SS block index (different from the first SS block index) on it, even if the first and second SS blocks are transmitted on the same antenna port.

[0032] In another alternative embodiment, the (DL Tx) antenna port may be associated with one or more CSI-RS resources. The antenna port associated with a first CSI-RS resource (having a first CSI-RS resource index) may correspond to a first DL Tx beam (beamforming pattern), and the antenna port associated with a second CSI-RS resource (having a second CSI-RS resource index) may correspond to a second DL Tx beam. Therefore, depending on the CSI-RS resource, the antenna port may correspond to different DL Tx beams, i.e., the first DL Tx beam or the second DL Tx beam. The first DL Tx beam may be different from the second DL Tx beam. The first CSI-RS resource may be different from the second CSI-RS resource, which may result in the first CSI-RS resource index being different from the second CSI-RS resource index. In one example, the first CSI-RS resource may be transmitted at a first time instance, and the second CSI-RS resource may be transmitted at a second time instance. In another example, the first and second CSI-RS resource transmission instances may overlap, and in some examples, they may completely overlap. In one example, the UE may assume that any transmission instance transmitting CSI-RS resources with the same CSI-RS resource index is transmitted on the same antenna port. The UE may not assume that a channel transmitting a first CSI-RS resource with a first CSI-RS resource index can be inferred from a channel transmitting a second CSI-RS resource with a second CSI-RS resource index (different from the first CSI-RS resource index) on it, even if the first and second CSI-RS resources are transmitted on the same antenna port.

[0033] In one embodiment, the user equipment (UE) receives parameters from a network entity (e.g., gNode B) as system information (SI) or a dedicated RRC message relating to the criteria for determining the selection / reselection of an SS block (or CSI-RS resource / port), and selects a serving SS block or CSI-RS resource / port based on the (re)selection criteria determined based on the received parameters. The serving SS block or CSI-RS resource / port can be used for path loss estimation in RACH and uplink communications as well as DL communications. The gNB can control the UE's selection of a serving SS block or CSI-RS resource / port by sending information about configuring the selection criteria, such as the UE's Tx power setting offset or the SS block / CSI-RS port-specific RSRP offset.

[0034] In one example, parameters related to selecting a serving DL Tx antenna port may include one or more RSRP offset values ​​and one or more RSRP thresholds. Based on the received parameters, the user equipment can select one or more DL Tx antenna ports whose RSRP measurements are higher than the RSRP thresholds as candidate DL Tx antenna ports. A ranking metric is calculated for the candidate DL Tx antenna ports by applying the RSRP offset values ​​to the RSRP measurements. The candidate DL Tx antenna ports are ranked based on the calculated ranking metric, and the DL Tx antenna port with the highest ranking is selected as the serving DL Tx antenna port. Each RSRP offset value of a DL Tx antenna port may depend on the beamwidth (or maximum beamforming gain) of the beam associated with the corresponding DL Tx antenna port and / or the load condition of the corresponding DL Tx antenna port. For example, a DL Tx antenna port associated with a beamwidth larger, or in other words, a smaller beamforming gain, may have a larger RSRP offset value. The load condition of a given DL Tx antenna port may be based on, for example, the number of users served by the DL Tx antenna port or the number of configured RACH resources associated with the DL Tx antenna port. In some examples, the user equipment can measure RSRP on a subset of DL Tx antenna ports, rank candidate DL Tx antenna ports, and select a serving DL Tx antenna port from the subset. In another example, a DL Tx antenna port can be selected as the serving DL Tx antenna port if the calculated ranking metric for the DL Tx antenna port is above a threshold.

[0035] In another example, the user equipment may receive parameters related to reselecting a serving DL Tx antenna port, including a first RSRP offset value associated with the current serving DL Tx antenna port, a second RSRP offset value associated with a DL Tx antenna port that is not currently selected as a serving DL Tx antenna port but is being evaluated for potential reselection as a serving DL Tx antenna port, and an evaluation duration used to decide whether to reselect the serving DL Tx antenna port. To make a reselection decision, the user equipment may calculate a ranking metric by applying the first RSRP offset value (e.g., a positive value) to the RSRP measurement of the current serving DL Tx antenna port and by applying the second RSRP offset value (e.g., a negative value) to the RSRP measurement of the candidate DL Tx antenna ports. If the user equipment verifies that the ranking of a candidate DL Tx antenna port is higher than the ranking of the current serving DL Tx antenna port within the indicated duration, the user equipment may perform a reselection of the serving DL Tx antenna port.

[0036] Network entities may include parameters related to SS block (re)selection as part of the basic SI, or may send them along with other SIs. If the user equipment is in connected mode, it can receive parameters related to SS block (re)selection for the secondary serving cell and / or for handover to the target cell as a dedicated RRC message from the network entity of the primary serving cell. Furthermore, the user equipment can receive CSI-RS resource / port (re)selection parameters in the dedicated RRC message as part of the CSI-RS configuration. Parameters related to reselecting the SS block or CSI-RS resource / port for RACH preamble retransmission can be included in the RACH configuration.

[0037] During the random access procedure, the User Equipment (UE) can select a serving DL Tx antenna port for each preamble (re)transmission of the RACH procedure based on the order of one or more DL Tx antenna ports. The UE can start with the highest-ordered DL Tx antenna port and then (if necessary) select the second-highest-ordered DL Tx antenna port for the preamble retransmission. If necessary, the UE can update the order before retransmission. Simple ordering criteria can be based on measurements utilizing some offset values. Ordering can also be based on at least one of the following: measurement period, the order of the earliest available RACH resources in time, or the availability of dedicated RACH resources, wherein each RACH resource is associated with at least one DL Tx antenna port.

[0038] For example, a user equipment (UE) can select a DL Tx antenna port with a measurement higher than a threshold of the most recently evaluated configuration. That is, if both DL Tx antenna ports have measurements above the threshold, and one was last measured 80 milliseconds (ms) ago while the other was measured only 5 milliseconds ago, the latter may be preferred. In another example, the UE can select the DL Tx antenna port with the earliest corresponding RACH opportunity among those whose measurements are above the threshold. In yet another example, the UE can apply different RSRP offset values ​​to the measurements of a DL Tx antenna port depending on whether the given DL Tx antenna port has an associated contention-free random access (CFRA) resource. The handover command can include information required for contention-based random access (CBRA) and CFRA, allowing the UE to select a serving DL Tx antenna port that may differ from the DL Tx antenna port reported in the measurement report and offers a dedicated RACH resource. Considering that contention-based CBRA may have a longer delay than CFRA, a larger RSRP offset value can be applied to give priority to DL Tx antenna ports associated with dedicated RACH resources over DL Tx antenna ports without dedicated RACH resources. In another example, a CFRA resource is assigned to the User Equipment (UE), and configuration of CBRA resources is also received. The CFRA and CBRA resources can be associated with the same or different DL Tx antenna ports. If the CFRA resource is within X time units of a CBRA RACH opportunity (e.g., in terms of slots, subframes, or ms) (the measurements of the corresponding DL Tx antenna ports for the CFRA and CBRA resources are above a threshold and are therefore considered a "valid" RACH transmission opportunity), the UE can skip the CBRARACH opportunity and transmit a RACH preamble on the CFRA. Therefore, the UE does not attempt to transmit RACH on the CBRA resource. The value of X can be configured by the network entity and can depend on the average delay difference between the CBRA and CFRA. In another example, multiple CFRA resources can be assigned to the UE, each associated with a different DL Tx antenna port. In this case, the UE can transmit RACH on the first available "valid" CFRA resource (the measurement for the corresponding DL Tx antenna port for the CFRA resource is above a threshold).

[0039] In another embodiment, the User Equipment (UE) may receive backoff parameters specific to or for a set of SS block / CSI-RS ports in a Random Access Response (RAR) message. The UE considers SS block / CSI-RS ports or sets of SS block / CSI-RS ports for which no backoff parameter is signaled; the backoff parameter is set to 0 ms. In one example, the UE may select a random backoff time for each SS block / CSI-RS port based on a uniform distribution between 0 and the backoff parameter for a given SS block / CSI-RS port. For subsequent preamble transmissions, the UE may select the SS block / CSI-RS port with the minimum backoff time from among those whose RSRP measurements are above an RSRP threshold. This mechanism can redistribute the RACH load across RACH resources associated with different SS block / CSI-RS ports.

[0040] In another embodiment, if each SS block or CSI-RS resource / port has a different DL Tx power, instead of the SS block RSRP or CSI-RS RSRP, the user equipment can receive a UL Tx power offset parameter, compare the resulting adjusted UL Tx power associated with each SS block or CSI-RS resource / port, and select an SS block or CSI-RS resource / port based on the adjusted UL Tx power, for example, requiring the lowest UL Tx power or a UL Tx power below a threshold.

[0041] In another embodiment, if each SS block or CSI-RS resource / port has a different DL Tx power, the user equipment can receive a PL (path loss) offset parameter, compare the resulting adjusted PL (adjusted by the PL offset parameter) associated with each SS block or CSI-RS resource / port, and select an SS block or CSI-RS resource / port based on the adjusted PL, for example, an SS block or CSI-RS resource / port with the minimum adjusted PL or an adjusted PL below a threshold.

[0042] In some of the examples above, the user equipment can measure RSRP / calculate UL Tx power / PL on a subset of DL Tx antenna ports, sort candidate DL Tx antenna ports, and select the SS block or CSI-RS resource / port corresponding to the serving DL Tx antenna port from the subset of DL Tx antenna ports.

[0043] In some examples, a user equipment (UE) may have one or more receive antenna groups. An Rx antenna group may include one or more Rx antenna ports or Rx beams. In one example, an antenna group may correspond to an antenna panel or an antenna subarray. Different receive antenna groups may have different antenna gains and may receive signals from different spatial directions. The spatial directions or angles of arrival supported by an antenna group may overlap with those of another antenna group. Similarly, a UE may have one or more transmit antenna groups, where a Tx antenna group includes one or more Tx beams. Different transmit antenna groups may have different antenna gains and may be able to transmit or send signals from different spatial directions. The spatial / transmit directions or offset / transmit angles supported by an antenna group may overlap with those of another antenna group. In one example, to determine RSRP or PL (e.g., UL Tx power calculation or selection of RACH resources for RACH transmission) from a DL Tx antenna port, the UE may be restricted to performing or using measurements only on a set of spatial directions using one or more Rx antenna groups, such that UL transmissions using one or more transmit antenna groups may also be transmitted on the same set of spatial directions. Measurements of spatial orientation not supported by the set of possible uplink transmit angles may not be used to determine the RSRP or PL associated with UL transmissions, such as UL Tx power calculations or RACH resource selection for RACH transmissions. In one example, the first antenna group is both the first Rx antenna group and the first Tx antenna group, and the second antenna group is only the second Rx antenna group. Therefore, the user equipment cannot use the second antenna group for UL transmissions. In this case, DL measurements used to determine the RSRP or PL associated with UL transmissions, such as UL Tx power calculations or RACH resource selection for RACH transmissions, can be restricted to being performed only on the first Rx antenna group.

[0044] User equipment preamble power settings after changing the service SS block or CSI-RS resource / port

[0045] During the random access procedure, the user equipment can change the serving SS block / CSI-RS port, which is used for path loss estimation and RACH resource determination for preamble retransmission.

[0046] In one embodiment, the network entity may instruct the user equipment (UE) to apply a preamble Tx power adjustment value to determine the preamble Tx power when the UE reselects an SS block or CSI-RS resource / port and retransmits the RACH preamble during the RACH process. In other embodiments, the UE may determine the preamble Tx power adjustment value according to one or more predefined or configured rules. For example, the gNB may measure and indicate the interference level of a subset of RACH resources associated with a DL Tx antenna port such as an SS block or CSI-RS resource / port, and the UE may derive the power adjustment value based on the interference level difference between the RACH resources of the previously selected DL Tx antenna port and the most recently selected DL Tx antenna port. Alternatively, the UE receiver may listen to the RACH resources and measure the interference level of the RACH resources. For example, using the determined preamble Tx power adjustment value, the UE may determine the preamble Tx power for retransmission as follows:

[0047] P PRACH =min{P CMAX，c，s (i), PREAMBLE_RECEIVED_TARGET_POWER+PL c，s +Δ offset}_[dBm],

[0048] Where P CMAX,c,s (i) is the maximum user equipment transmit power configured for time slot i of the DL Tx antenna port s of serving cell c, PL c，s This is a path loss estimation for the DL Tx antenna port s of serving cell c, Δ offset It is a definite leading Tx power adjustment value, and PREAMBLE_RECEIVED_TARGET_POWER is given by the following:

[0049] PREAMBLE_RECEIVED_TARGET_POWER=preambleInitialReceivedTargetPower+DELTA_PREAMBLE+POWER_RAMPING_COUNTER*powerRampingStep

[0050] Where `preamblelnitialReceivedTargetPower` is the target preamble Rx power indicated by the NE, `DELTA_PREAMBLE` is the power offset depending on the RACH preamble format or the number of preamble repetitions, and `POWER_RAMPING_COUNTER` is the number of power increments initially set to 0 (i.e., the initial preamble transmission). When a user equipment changes its serving DL Tx antenna port for retransmission, the power increment level for RACH preamble retransmissions can remain constant to avoid additional RACH delays, especially for power-constrained user equipment. In addition to the maximum allowed number of preamble transmissions for a given random access procedure, the maximum allowable increase in power increment can be predefined and known to both the user equipment and the network entity, or it can be configured and indicated by the network entity.

[0051] On the other hand, if a power increase occurs due to a higher interference level in a previously used RACH resource, maintaining the same power increase level for the RACH resource associated with the previously selected DL Tx antenna port might cause unnecessary interference in the RACH resource associated with the newly selected DL Tx antenna port, which has a lower interference level. In this case, it is desirable to adjust the preamble transmission power level based on the interference level of the newly selected RACH resource or the interference level difference between the two RACH resources. To determine the RACH preamble power adjustment value for a given change from the first DL Tx antenna port to the second DL Tx antenna port, the gNB can perform noise and interference estimation for a subset of RACH time / frequency resources, where the subset of RACH time / frequency resources is associated with a DL Tx antenna port (or a set of DL Tx antenna ports).

[0052] Alternatively, the preamble Tx power adjustment value can be determined based on the user equipment's power increase level (i.e., the amount of power increase). That is, if a change in the serving DL Tx antenna port occurs after the user equipment has already reached a higher power increase level, a larger preamble Tx power adjustment value can be applied. The user equipment can receive a set of preamble Tx power adjustment values, each applicable to a different power increase level. Network entities can transmit the set of preamble Tx power adjustment values ​​in the RACH configuration as part of system information, or as part of a handover command or other dedicated RRC message.

[0053] In some examples, the leader Tx power adjustment value Δ offset It can be configured by a network entity for each of a subset of one or more DL Tx antenna ports s. For example, for DL ​​Tx antenna port 0, □Δ offsetPossibly 0dB; for DL ​​Tx antenna port 1, Δ offset It could be 3dB, and for DL ​​Tx antenna port 3, Δ offset It could be -2dB. For cases where Δ is not configured... offset For a DL antenna port, such as DL Tx antenna port 2, the user equipment can assume a value of 0dB. Network entities can determine the Δ value for different DL Tx antenna ports by measuring the relative interference level on a subset of RACH resources associated with each different DL Tx antenna port. offset When a user equipment is ready to retransmit a RACH preamble on a RACH resource associated with a (re)selected SS block or CSI-RS resource / port, the user equipment should apply the Δ associated with the (re)selected SS block or CSI-RS resource / port. offset .

[0054] In one example, during the RACH process, if the user equipment switches from CBRA to CFRA, the user equipment will determine PREAMBLE_RECEIVED_TARGET_POWER as follows:

[0055] PREAMBLE_RECEIVED_TARGET_POWER=preambleInitiaIReceivedTargetPower+DELTA_PREAMBLE

[0056] When a user equipment switches from CBRA to CFRA, POWER_RAMPING_COUNTER is not used. If the RACH process is not completed and the user equipment switches from CFRA to CBRA, the user equipment increments POWER_RAMPING_COUNTER and determines PREAMBLE_RECEIVED_TARGET_POWER as before.

[0057] PREAMBLE_RECEIVED_TARGET_POWER=preambleInitialReceivedTargetPower+DELTA_PREAMBLE+POWER_RAMPING_COUNTER*powerRampingStep,

[0058] In another example, the user equipment maintains separate POWER_RAMPING_COUNTERs for CFRA and CBRA, and determines the appropriate counter to use for PREAMBLE_RECEIVED_TARGET_POWER.

[0059] For CFRA:

[0060] PREAMBLE_RECEIVED_TARGET_POWER=preambleInitinlReceivedTargetPower+DELTA_PREAMBLE+POWER_RAMPING_COUNTER_CFRA*powerRampingStep,

[0061] For CBRA:

[0062] PREAMBLE_RECEIVED_TARGET_POWER=preamblelinitialReceivedTargetPower+DELTA_PREAMBLE+POWER_RAMPING_COUNTER_CBRA*powerRampingStep,

[0063] If the RACH procedure is not completed and the user equipment switches from CFRA to CBRA, the user equipment will increment POWER_RAMPING_COUNTER_CFRA and POWER_RAMPING_COUNTER_CBRA. Increasing these two power increment counters compensates for inter-cell interference affecting both CFRA and CBRA. Conversely, if the user equipment switches from CBRA to CFRA or continues to use CBRA for RACH transmission, the user equipment will only increment POWER_RAMPING_COUNTER_CBRA.

[0064] Figure 2 The illustration shows a plan view 200 for the respective transmit beams of each of the exemplary base station and user equipment, which can be associated with one of a pair of serving synchronization signal blocks for a random access channel. Figure 2In the example illustrated, the user equipment's channel can provide two suitable SS blocks, SS block K and SS block J, for the serving SS block. The user equipment first selects SS block K as the serving SS block and transmits three RACH preambles. The first two transmissions are performed using the same user equipment Tx beam with a power increase in the second transmission, while the third transmission is performed using a different user equipment Tx beam. When the user equipment changes its Tx beam, the user equipment power increase remains constant, and the user equipment calculates the preamble Tx power based at least on the most recent path loss estimate and power increase. For the fourth preamble transmission, the user equipment changes the serving SS block to SS block J, updates the path loss estimate based on measurements of SS block J, and applies a preamble Tx power adjustment value corresponding to power increase level 1 (i.e., one power increase) to determine the preamble Tx power. When the maximum power is reached, the user equipment can transmit at maximum power if the recalculated power for the new user equipment Tx beam or for the new serving SS block (SS block J) is still at or above the maximum configured power. The maximum configuration power can be set for each cell or for each cell's DL Tx antenna port (SS block or CSI-RS resource / port).

[0065] Figure 3 The illustration shows a flowchart 300 for providing beam selection in a user equipment using downlink transmit antenna port-specific adjustments. More specifically, a method in a user equipment is provided. The method includes receiving 302 a respective reference signal associated with each of one or more downlink transmit antenna ports in a wireless communication network. Determining 304 a value for each of one or more measurable characteristics relative to each of the received reference signals. Receiving 306 one or more parameters including one or more adjustments, wherein each adjustment is specific to one of the downlink transmit antenna ports and includes adjustments in the form of one or more respective offset values ​​to be applied to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals. The method also includes selecting 308 at least one downlink transmit antenna port for use as a serving downlink transmit antenna port for the user equipment based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjustments have been applied to the corresponding determined values.

[0066] In some cases, one or more downlink transmit antenna ports may be synchronization signal block antenna ports, or one or more channel state information reference signal antenna ports of one or more channel state information reference signal resources.

[0067] In some cases, the method may further include providing the wireless communication network with an identifier of at least one selected serving downlink transmit antenna port by transmitting at least one random access preamble on at least one random access channel resource, wherein the at least one random access channel resource is associated with the selected at least one serving downlink transmit antenna port. In some of these examples, the method may further include selecting at least one random access preamble from at least one subset of random access preambles, wherein the at least one subset of random access preambles is associated with the selected at least one serving downlink transmit antenna port.

[0068] In some instances, the method may further include receiving an indication of at least one contention-free random access resource associated with a first set of downlink transmit antenna ports and at least one contention-based random access resource associated with a second set of downlink transmit antenna ports, and selecting at least one downlink transmit antenna port from the first set and the second set of downlink transmit antenna ports to be used as a serving downlink transmit antenna port.

[0069] In some cases, the method may further include transmitting an indication of at least one selected serving downlink transmit antenna port on the physical uplink control channel.

[0070] In some cases, the method may further include receiving one or more parameters in at least one of a dedicated radio resource control message or a broadcast system information message.

[0071] In some cases, the measurable characteristic may include at least the reference signal received power. In some of these instances, one or more adjustments may include one or more reference signal received power offset values ​​and one or more reference signal received power thresholds. Furthermore, one or more reference signal received power offset values ​​may include at least one of a first value associated with the currently serving downlink transmit antenna port or a second value associated with a downlink transmit antenna port that is not currently selected as the serving downlink transmit antenna port. In some similar or other cases, one or more reference signal received power offset values ​​may depend on the beamwidth of the beam associated with one or more downlink transmit antenna ports. In some cases, the selection of at least one downlink transmit antenna port is based on a comparison of the resulting values ​​of the reference signal received power after the received one or more reference signal received power offset values ​​are applied together with one or more reference signal received power thresholds.

[0072] In some cases, one or more adjustments depend on the load condition of each of one or more downlink transmit antenna ports, wherein the load condition includes at least one of the number of users served by the corresponding downlink transmit antenna port or the number of configured random access channel resources associated with the corresponding downlink transmit antenna port.

[0073] In some instances, one or more parameters may include a duration, which is used to determine whether to reselect the service downlink transmit antenna port.

[0074] In some cases, the method may further include sorting one or more downlink transmit antenna ports based on determined values ​​of measurable characteristics and one or more received parameters; and selecting at least one serving downlink transmit antenna port for each of one or more random access preamble transmissions in the random access procedure based on the sorting of the one or more downlink transmit antenna ports. In some of these instances, the sorting may also be based on at least one of measurement period, the order of the earliest available random access channel resources in time, or the availability of dedicated random access channel resources, wherein each random access channel resource is associated with at least one downlink transmit antenna port.

[0075] Figure 4 The flowchart 400 illustrates a method for a network entity to provide downlink transmit antenna port-specific adjustments to one or more user equipments for beam selection. More specifically, a method in a network entity is provided. The method includes transmitting 402 a respective reference signal via each of one or more downlink transmit antenna ports, which can be received by one or more user equipments, and determining values ​​for each of one or more measurable characteristics relative to each of the received reference signals. The method in the network entity also includes determining 404 one or more parameters, which can then be transmitted to one or more user equipments, the parameters including one or more adjustments, wherein each adjustment is specific to one of the downlink transmit antenna ports, and includes adjustments in the form of one or more respective offset values ​​applied by the user equipment to at least some of the one or more determined values ​​of the measurable characteristics of the received reference signals, selecting at least one downlink transmit antenna port as a serving downlink transmit antenna port for the user equipment based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signals after the one or more adjusted values ​​have been applied to the corresponding determined values.

[0076] Figure 5The flowchart 500 illustrates a method for determining a preamble transmit power adjustment value used by a user equipment (UE) during a random access procedure based on downlink transmit antenna port-specific parameters received from a network entity. More specifically, a method is provided in a UE during a random access procedure. The method includes: 502 Selecting a first downlink transmit antenna port; 504 Transmitting a first preamble at a first preamble transmit power on one of a first subset of random access channel resources, wherein the first subset of random access channel resources is associated with the first downlink transmit antenna port; 506 Selecting a second downlink transmit antenna port, wherein the second downlink transmit antenna port is different from the first downlink transmit antenna port, if no random access response message including an indication of the first preamble is received within a random access response reception time window; 508 Determining a preamble transmit power adjustment value based on one or more downlink transmit antenna port-specific parameters received from a wireless communication network; and 510 Determining a second preamble transmit power based on the determined preamble transmit power adjustment value and the first preamble transmit power. Then, a second preamble with a determined second preamble transmission power is transmitted on one of the second subsets of the random access channel resources, wherein the second subset of the random access channel resources is associated with a second downlink transmit antenna port.

[0077] In some instances, the preamble transmit power adjustment value can be based on the parameter difference between specific downlink transmit antenna port parameters for the first and second downlink transmit antenna ports.

[0078] In some instances, the first and second downlink transmit antenna ports can be one or more of a synchronization signal block antenna port or a channel state information reference signal antenna port.

[0079] In some instances, the preamble transmit power adjustment value can be derived by the user equipment based on antenna port-specific parameters received from the wireless communication network.

[0080] In some instances, determining the preamble transmit power adjustment value may include an indication of receiving the preamble transmit power adjustment value as part of one or more downlink transmit antenna port-specific parameters. In some of these instances, the preamble transmit power adjustment value may be indicated in a system information block. In some of these and / or other instances, the preamble transmit power adjustment value may be indicated in a dedicated radio resource control message. Furthermore, the preamble transmit power adjustment value may depend on the amount of power increase that occurs before transmitting the second preamble during random access. When determining the second preamble transmit power, based on the set of received transmit power adjustment values, the transmit adjustment value may depend on earlier power increase levels, where each transmit power adjustment value in that set applies to a different increase level.

[0081] In some instances, the preamble transmit power adjustment value may be based on a first measurement of a first subset of random access channel resources and a second measurement of a second subset of random access channel resources. In some of these instances, specific parameters of the respective downlink transmit antenna ports may include an indication of the interference level of the subsets of random access channel resources associated with the selected first and second downlink transmit antenna ports. When detecting the interference level, the base station of the wireless communication network may perform noise and interference estimation for subsets of random access channel time and frequency resources associated with specific downlink transmit antenna ports, respectively. In some of these or other instances, the method may further include receiving indications of the first and second measurements; and using the first and second measurements to determine the preamble transmit power adjustment value according to one or more predefined or preconfigured rules. Furthermore, the method may further include performing measurements on the first subset and the second subset of random access channel resources to obtain the first and second measurements.

[0082] Figure 6 The flowchart 600 illustrates a method for a network entity to provide downlink transmit antenna port-specific parameters to one or more user equipments (UEs) to determine a preamble transmit power adjustment value. More specifically, a method is provided within a network entity during a random access procedure. The method includes determining 602 one or more downlink transmit antenna port-specific parameters from which the UE can determine the preamble transmit power adjustment value; and transmitting 604 the one or more determined downlink transmit antenna port-specific parameters to the one or more UEs. The method further includes monitoring 606 a first preamble from the UE on a first subset of random access channel resources, wherein the first preamble is transmitted by the UE at a first preamble transmit power. The first subset of random access channel resources is associated with a first downlink transmit antenna port selected by the UE. The method also includes monitoring 608 a second preamble, wherein the second preamble is transmitted by the UE on a second subset of random access channel resources at a second preamble transmit power, the second preamble transmit power being determined using the preamble transmit power adjustment value and the first preamble signal transmit power. When a user equipment does not receive a random access response message including an indication of a first preamble from a network entity within the random access response reception time window, a second subset of the random access channel resources is associated with a second downlink transmit antenna port that is different from the first downlink transmit antenna port selected by the user equipment.

[0083] It should be understood that, regardless of the specific steps shown in the figures, various additional or different steps may be performed depending on the embodiment, and one or more of these specific steps may be rearranged, repeated, or eliminated entirely depending on the embodiment. Furthermore, some of the steps may be performed simultaneously or repeatedly on a procedural or sequential basis while performing other steps. Additionally, different steps may be performed through different elements in the disclosed embodiments or within a single element of the disclosed embodiments.

[0084] Figure 7 This is an example block diagram of an apparatus 700 (such as wireless communication device 110) according to a possible embodiment. Apparatus 700 may include a housing 710, a controller 720 located within the housing 710, audio input and output circuitry 730 coupled to the controller 720, a display 740 coupled to the controller 720, a transceiver 750 coupled to the controller 720, an antenna 755 coupled to the transceiver 750, a user interface 760 coupled to the controller 720, a memory 770 coupled to the controller 720, and a network interface 780 coupled to the controller 720. Apparatus 700 can perform the methods described in all embodiments.

[0085] Display 740 may be a viewfinder, liquid crystal display (LCD), light-emitting diode (LED) display, plasma display, projection display, touchscreen, or any other device for displaying information. Transceiver 750 may include a transmitter and / or receiver. Audio input and output circuitry 730 may include a microphone, speaker, transducer, or any other audio input and output circuitry. User interface 760 may include a keypad, keyboard, buttons, touchpad, joystick, touchscreen display, another additional display, or any other device that can be used to provide an interface between a user and an electronic device. Network interface 780 may be a universal serial bus (USB) port, Ethernet port, infrared transmitter / receiver, IEEE 1394 port, WLAN transceiver, or any other interface that can connect the device to a network, device, or computer and send and receive data communication signals. Memory 770 may include random access memory, read-only memory, optical memory, solid-state memory, flash memory, removable memory, hard disk drive, cache, or any other memory that can be coupled to the device.

[0086] Device 700 or controller 720 can implement any operating system, such as Microsoft. or Android TM Or any other operating system. The device operating software can be written in any programming language (such as C, C++, Java, or Visual Basic). The device software can also be written in application frameworks (such as...). frame, The software and / or operating system may run on a framework or any other application framework. The software and / or operating system may be stored in memory 770 on device 700 or elsewhere. Device 700 or controller 720 may also use hardware to implement the disclosed operations. For example, controller 720 may be any programmable processor. The disclosed embodiments may also be implemented with: general-purpose or special-purpose computers, programmable microprocessors or microprocessors, peripheral integrated circuit elements, application-specific integrated circuits or other integrated circuits, hardware / electronic logic circuits (such as discrete component circuits), programmable logic devices (such as programmable logic arrays), field-programmable gate arrays, etc. Typically, controller 720 may be one or more controller or processor devices capable of operating the device and implementing the disclosed embodiments. Some or all of the additional elements of device 700 may also perform some or all of the operations of the disclosed embodiments.

[0087] The methods of this disclosure can be implemented on a programmable processor. However, the controller, flowchart, and modules can also be implemented on a general-purpose or special-purpose computer, a programmable microprocessor or microcontroller, and peripheral integrated circuit elements, integrated circuits, hardware electronics or logic circuits (such as discrete component circuits), programmable logic devices, etc. Generally, any device residing with a finite state machine capable of implementing the flowcharts shown in the figures can be used to implement the processor functions of this disclosure.

[0088] Although this disclosure has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be readily apparent. For example, various components of the embodiments may be interchanged, added to, or substituted in other embodiments. Furthermore, not all elements of each figure are essential to the operation of the disclosed embodiments. For example, this will enable those skilled in the art to make and use the teachings of this disclosure by simply employing the elements of the independent claims. Therefore, the embodiments of this disclosure as set forth herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of this disclosure.

[0089] In this document, relational terms such as “first,” “second,” etc., may be used only to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Phrases followed by a list, such as “at least one of,” “at least one selected from the group,” or “at least one selected from,” are defined to mean one, some, or all of the elements in the list, but not necessarily all of them. The terms “comprising,” “including,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but may also include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Without further limitations, an element followed by “a,” “an,” etc., does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes that element, unless further constraints are imposed. Additionally, the term “another” is defined as at least a second or more. The terms “comprising,” “having,” etc., as used herein, are defined as “comprising.” Furthermore, the background section is written as the inventor's understanding of the context of some embodiments at the time of submission and includes the inventor's own awareness of any problems with the prior art and / or problems encountered in the inventor's own work.

Claims

1. A method in a user equipment, the method comprising: Receive one or more reference signals associated with each of one or more downlink transmit antenna ports in a wireless communication network; Determine a value for each of one or more measurable characteristics relative to each of the received reference signals; The receiver includes one or more parameters that are adjusted, each adjustment corresponding to at least one of the downlink transmit antenna ports, and includes one or more respective reference signal receive power offset values, which will be applied to at least one of the one or more determined values ​​of the measurable characteristics of the received reference signal; as well as Based on a comparison of the resulting values ​​of the measurable characteristics of the received reference signal after one or more adjustments have been applied to corresponding determined values, at least one downlink transmit antenna port is selected as the serving downlink transmit antenna port for the user equipment, wherein the one or more respective reference signal receive power offset values ​​are applied to one or more determined values ​​of the measurable characteristics of the received reference signal based on whether the corresponding associated downlink transmit antenna port has associated contention-free random access channel resources.

2. The method of claim 1, further comprising: The parameters are received in at least one of a dedicated radio resource control message or a broadcast system information message.

3. The method of claim 1, wherein, The measurable characteristic includes at least a reference signal received power, and wherein the one or more adjustments include one or more reference signal received power offset values ​​and one or more reference signal received power thresholds.

4. The method of claim 3, wherein, One or more reference signal received power offset values ​​include at least one of a first value associated with the current serving downlink transmit antenna port and a second value associated with a downlink transmit antenna port that is not currently selected as the serving downlink transmit antenna port.

5. The method of claim 3, wherein, The selection of the at least one service downlink transmit antenna port is based on a comparison of the resulting value of the reference signal received power after one or more reference signal received power offset values ​​are applied together with one or more reference signal received power thresholds.

6. The method of claim 1, wherein, The one or more parameters include a duration, wherein the duration is used to determine whether to reselect the service downlink transmit antenna port.

7. The method of claim 1, further comprising: Based on the determined values ​​of the measurable characteristics and the received one or more parameters, the one or more downlink transmit antenna ports are sorted. as well as The at least one serving downlink transmit antenna port is selected based on the order of the one or more downlink transmit antenna ports for each of the one or more random access preamble transmissions in the random access procedure.

8. The method of claim 1, wherein, Each reference signal is associated with one or more downlink transmit antenna ports.

9. The method of claim 1, further comprising providing the wireless communication network with an identifier of the selected at least one serving downlink transmit antenna port by transmitting at least one random access preamble on at least one random access channel resource, wherein the at least one random access channel resource is associated with the selected at least one serving downlink transmit antenna port.

10. The method of claim 1, further comprising: Receive an indication of at least one contention-free random access resource associated with a first set of downlink transmit antenna ports and at least one contention-based random access resource associated with a second set of downlink transmit antenna ports, and At least one downlink transmit antenna port is selected from the first set and the second set of the downlink transmit antenna ports to be used as the serving downlink transmit antenna port.

11. The method of claim 1, further comprising: Instructions for at least one selected service downlink transmit antenna port are transmitted on the physical uplink control channel.

12. The method of claim 1, wherein, The one or more adjustments depend on the load condition of each of the one or more downlink transmit antenna ports, wherein the load condition includes at least one of the number of users served by the corresponding downlink transmit antenna port or the number of configured random access channel resources associated with the corresponding downlink transmit antenna port.

13. The method according to claim 1, wherein, The selection of the at least one downlink transmit antenna port is further based on the order of the earliest available random access channel resources in time, wherein each random access channel resource is associated with at least one downlink transmit antenna port.

14. A user equipment, comprising: A transceiver that receives one or more reference signals associated with each of one or more downlink transmit antenna ports in a wireless communication network; as well as A controller that determines values ​​for each of one or more measurable characteristics relative to each of the received reference signals; The transceiver receives one or more parameters including one or more adjustments, each adjustment corresponding to at least one of the downlink transmit antenna ports, and includes one or more respective reference signal receive power offset values, which will be applied to at least one or more determined values ​​of the measurable characteristics of the received reference signal; and The controller selects at least one downlink transmit antenna port to be used as a serving downlink transmit antenna port for the user equipment based on a comparison of the result values ​​of the measurable characteristics of the received reference signal after one or more adjustments have been applied to corresponding determined values, wherein the one or more respective reference signal receive power offset values ​​are applied to one or more determined values ​​of the measurable characteristics of the received reference signal based on whether the corresponding associated downlink transmit antenna port has associated contention-free random access channel resources.

15. The user equipment according to claim 14, wherein, The transceiver further receives the one or more parameters in at least one of a dedicated radio resource control message or a broadcast system information message.

16. The user equipment according to claim 14, wherein, The measurable characteristic includes at least a reference signal received power, and wherein the one or more adjustments include one or more reference signal received power offset values ​​and one or more reference signal received power thresholds.

17. The user equipment according to claim 14, wherein, The controller further sorts the one or more downlink transmit antenna ports based on the determined values ​​of the measurable characteristics and the received one or more parameters, and selects the at least one serving downlink transmit antenna port based on the sorting of the one or more downlink transmit antenna ports for each of the one or more random access preamble transmissions in the random access procedure.

18. The user equipment according to claim 14, wherein, Each reference signal is associated with one or more downlink transmit antenna ports.

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