User Equipment and Base Station Involved in Prioritized Random Access

Abstract

To provide a method, communication device, base station, and integrated circuit for promoting provision of an improved random access procedure in which various entities (UE, gNB) participate.SOLUTION: A communication system includes a communication device comprising a processor which upon being triggered by a random access event, determines random access transmission parameters on the basis of the random access event and random access configuration information and a transmitter for transmitting a random access message to a base station using the determined random access transmission parameters. Part of the random access configuration information is transferred using a designated radio resource control (RRC) message and other part of the random access configuration information is transferred using a minimum system information (SI) message.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure is directed to methods, devices, and articles for communication systems, such as 3GPP® communication systems. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP) is currently working on the next release (Release 15) of technical specifications for next-generation cellular technology, also known as the fifth generation (5G). At the 71st Radio Access Network (RAN) meeting of the 3GPP Technical Specification Group (TSG) in Gothenburg in March 2016, the first 5G study item, "Study on New Radio Access Technologies," including RAN1, RAN2, RAN3, and RAN4, was approved and is expected to become the Release 15 work item that will define the initial 5G standard. The purpose of this study item is to develop "New Radio (NR)" access technologies (RATs) that operate at frequencies up to 100 GHz and support the wide range of use cases defined in the RAN Requirements Study (see, for example, Non-Patent Document 1, available at www.3gpp.org and incorporated herein by reference in its entirety).

[0003] One objective is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios defined in TR 38.913, including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). For example, deployment scenarios for eMBB may include indoor hotspots, dense urban areas, rural areas, urban macro areas, and high-speed areas. Deployment scenarios for URLLC may include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time control of vehicles, and wide-area monitoring and control systems for smart grids. mMTC may include scenarios using a large number of devices with non-time-critical data transfer, such as smart wearables and sensor networks. The services eMBB and URLLC are similar in that both require very high bandwidth, but differ in that URLLC services require ultra-low latency.

[0004] A second objective is to achieve forward compatibility: backward compatibility with Long Term Evolution (LTE, LTE-A) cellular systems is not required, thereby facilitating the introduction of entirely new system designs and / or novel features.

[0005] The basic physical layer signal waveform will be an OFDM-based signal waveform with potential support for non-orthogonal waveforms and multiple access. Additional features to OFDM, such as DFT-S-OFDM and / or variants of DFT-S-OFDM and / or filtering / windowing, are being further considered. In LTE, CP-based OFDM and DFT-S-OFDM are used as waveforms for downlink and uplink transmissions, respectively. One of the design goals in NR is to achieve as common a waveform as possible for the downlink, uplink, and sidelink.

[0006] To achieve the above objectives, in addition to waveforms, some basic frame structure(s) and channel coding scheme(s) will be developed. This study will also seek a common understanding of what is needed in terms of radio protocol structure and architecture to achieve the above objectives. Furthermore, the technical features required to enable the new RAT to meet the above objectives will be considered, including efficient multiplexing of traffic for different services and use cases on the same contiguous block of spectrum.

[0007] 3GPP's standardization of NR for 5G systems is still in its infancy, leaving some issues unclear. For example, there has been discussion about supporting a prioritization mechanism for the random access procedure performed between user equipment and base stations. However, no definitive agreement has been reached on how to efficiently implement prioritized random access. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] 3GPP TR 38.913 "Study on Scenarios and Requirements for Next Generation Access Technologies" current version 14.3.0 Summary of the Invention

[0009] One non-limiting and exemplary embodiment facilitates providing an improved random access procedure involving various entities (UE, gNB).

[0010] A main aspect of the present disclosure is a communication device, a processor that, in operation, when triggered by a random access event, determines random access transmission parameters based on the random access event and random access configuration information; a transmitter that, during operation, transmits a random access message to a base station using the random access transmission parameters; Equipped with a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; It is a communication device.

[0011] In one general first aspect, the technology disclosed herein features a user equipment including a processor and a transmitter. The processor determines random access transmission parameters to be used, when triggered by one of a plurality of random access events, to transmit a random access message to a base station controlling a radio cell of a mobile communication system in which the user equipment is located. The random access transmission parameters are determined at least in part based on the random access event that triggered the transmission of the random access message and random access configuration information. The random access configuration information associates each of the plurality of random access events with a set of random access transmission parameters among a plurality of random access transmission parameters usable by the user equipment to transmit the random access message to the base station. The transmitter transmits the random access message to the base station using the determined random access transmission parameters.

[0012] In one general first aspect, the technology disclosed herein features a base station including the following receiver, processor, and transmitter: the receiver receives a random access message from a user equipment located in a radio cell of a mobile communication system controlled by the base station, and the random access message is transmitted by the user equipment when triggered by one of a plurality of random access events; the processor determines random access transmission parameters to be used by the user equipment to transmit the random access message, and determines back-off parameters to be used by the user equipment to determine at least a period of time the user equipment needs to wait before initiating another random access channel procedure; and the transmitter transmits a random access response message to the user equipment, including the determined back-off parameters, in response to the transmitted random access message.

[0013] In one general second aspect, the technology disclosed herein features a user equipment including a transmitter, a receiver, and a processor: the transmitter, when triggered by one of a plurality of random access events, transmits a random access message to a base station controlling a radio cell of a mobile communication system in which the user equipment is located; the receiver, in response to the transmitted random access message, receives a random access response message from the base station, the random access response message including a back-off index; the processor, based on the received back-off index and a back-off index table, determines a back-off time value indicating at least a period of time the user equipment must wait before initiating another random access channel procedure, the back-off index table associating different back-off time values ​​with the back-off index and at least one or more of a plurality of random access events that may trigger transmission of the random access message.

[0014] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof.

[0015] Additional benefits and advantages of the disclosed embodiments will be apparent from the specification and drawings, and while these benefits and / or advantages may be obtained individually through various embodiments and features of the specification and drawings, not all of them need be provided to obtain one or more of such benefits and / or advantages.

[0016] In the following, exemplary embodiments will be described in more detail with reference to the accompanying drawings and drawings. [Brief explanation of the drawings]

[0017] [Figure 1] 1 illustrates an example architecture of a 3GPP NR system. [Figure 2] 1 illustrates an exemplary user and control plane architecture for LTE, an eNB, and a UE. [Figure 3] Different subcarrier spacings of 15 kHz, 30 kHz, and 60 kHz and the resulting symbol durations are illustrated. [Figure 4] Illustrates the system information acquisition message exchange currently being discussed for 5g NR. [Figure 5] 10 illustrates an example of a message exchange between an eNB and a UE when performing a contention-based RACH procedure. [Figure 6] 10 illustrates an example of a message exchange between an eNB and a UE when performing a contention-free RACH procedure. [Figure 7] 1 illustrates an exemplary and simplified structure of a UE and an eNB. [Figure 8] Illustrates a simple scenario where a UE is connected to gNB1 and has neighboring cells that are each controlled by a different gNB. [Figure 9] 1 illustrates different PRACH resources, including three dimensions of the PRACH resource: time, frequency of the radio resource, and preamble sequence. [Figure 10] FIG. 10 is a sequence diagram of the behavior of a UE according to a modified example of the first embodiment. [Figure 11] FIG. 10 is a sequence diagram of the behavior of a base station according to a modified example of the first embodiment. [Figure 12] FIG. 10 is a sequence diagram of the behavior of a UE according to a modified example of the second embodiment. [Figure 13] FIG. 10 is a sequence diagram of the behavior of a base station according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Basis of this Disclosure

[0019] 5G NR System Architecture and Protocol Stack

[0020] As presented in the Background section, 3GPP is working on the next release of fifth-generation cellular technology, simply referred to as 5G, which includes the development of new radio access technologies (NR) operating at frequencies up to 100 GHz. 3GPP must identify and develop the technical elements necessary to successfully standardize an NR system that meets both immediate market demands and longer-term requirements in a timely manner. To accomplish this, the evolution of the air interface and radio network architectures is considered in the study item "New Radio Access Technologies." The results and consensus are contained in Technical Report TR 38.804 v14.0.0, the entire contents of which are incorporated herein by reference.

[0021] Among other things, a tentative agreement has been reached on the overall system architecture. The NG-RAN (Next Generation-Radio Access Network) consists of gNBs, which provide the NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination towards the UE. The gNBs are interconnected with each other via the Xn interface. The gNBs are also connected to the NGC (Next Generation Core) via the Next Generation (NG) interface, more specifically to the AMF (Access and Mobility Management Function) via the NG-C interface and to the UPF (User Plane Function) via the NG-U interface. The NG-RAN architecture is illustrated in Figure 1, which is taken from TS 38.300 v.0.4.1, section 4, which is incorporated herein by reference.

[0022] To support this, various different deployment scenarios are currently being discussed, as reflected, for example, in 3GPP TR 38.801 v14.0.0, the entire contents of which are incorporated herein by reference. For example, a decentralized deployment scenario (section 5.2 of TR 38.801, with centralized deployment exemplified in section 5.4) is presented therein, in which base stations supporting 5G NR can be deployed. Figure 2 illustrates an exemplary decentralized deployment scenario and is based on Figure 5.2.-1 of TR 38.801, discussed above, but additionally illustrates an LTE eNB as well as user equipment (UE) connected to both a gNB and an LTE eNB (which would be understood as an eNB according to previous 3GPP standard releases such as LTE and LTE-A). As previously mentioned, the new eNB for NR 5G may typically be referred to as a gNB.

[0023] An eLTE eNB, as typically defined in TR 38.801, is an evolution of the eNB that supports connectivity to EPC (Evolved Packet Core) and NGC (Next Generation Core).

[0024] The NR user plane protocol stack is currently defined in TS 38.300 v0.4.1, section 4.4.1. The PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), and MAC (Medium Access Control) sublayers terminate at the gNB on the network side. In addition, a new access stratum (AS) sublayer (SDAP, Service Data Adaptation Protocol) is introduced on top of PDCP, as described in sub-clause 6.5 of TS 38.300 v1.0.0. The NR control plane protocol stack is defined in TS 38.300, section 4.4.2. An overview of Layer 2 functions is given in sub-clause 6 of TS 38.300. The functions of the PDCP, RLC, and MAC sublayers are listed in sub-clauses 6.4, 6.3, and 6.2 of TS 38.300. The functions of the RRC layer are listed in sub-clause 7 of TS 38.300. The above-mentioned sub-clauses of TS 38.300 are incorporated herein by reference.

[0025] The new NR layer currently typically assumed for 5G systems may be based on the user plane structure currently used in LTE(-A) communication systems, although it should be noted that not all details of the NR layer have yet been finalized.

[0026] As specified in TR 38.913, NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps downlink and 10 Gbps uplink) and a user-perceived data rate approximately three times that offered by IMT-Advanced. On the other hand, for URLLC, more stringent requirements are placed on ultra-low latency (0.5 ms for user plane latency on UL and DL, respectively) and high reliability (1-10 ms within 1 ms). -5 Finally, mMTC is imposed on high connection density (1,000,000 devices / km in urban environments). 2 ), broad coverage in harsh environments, and extremely long battery life (15 years) for low-cost devices.

[0027] Therefore, OFDM numerology (e.g., subcarrier spacing, OFDM symbol period, cyclic prefix (CP) period, and number of symbols per scheduling interval) appropriate for one use case may not work well for another. For example, low-latency applications may require a shorter symbol period (hence, larger subcarrier spacing) and / or fewer symbols per scheduling interval (also called TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads require longer CP periods than scenarios with short delay spreads. Therefore, subcarrier spacing should be optimized to maintain similar CP overhead. At the 3GPP RAN1#84bis meeting (April 2016, Busan), it was agreed that NR should support multiple values ​​of subcarrier spacing. The subcarrier spacing value is derived from a specific value of the subcarrier spacing multiplied by N, where N is an integer. At the RAN1 conference RAN1#85 (May 2016, Nanjing), it was concluded that LTE-based numerology, including 15 kHz subcarrier spacing, is the baseline design for NR numerology as a practical assumption. Regarding the scaling factor N, the baseline design assumption for NR numerology is N=2. n It was concluded that a lower selection of numerology candidates may be made at a future meeting. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, etc. are currently being considered. Figure 3 exemplarily shows three different subcarrier spacings (15 kHz, 30 kHz, and 60 kHz) and the corresponding symbol durations. Symbol duration T u and the subcarrier spacing Δf is expressed by the formula Δf=1 / T u Similar to LTE systems, the term "resource element" may be used to denote the smallest resource unit consisting of one subcarrier over the length of one OFDM / SC-FDMA symbol.

[0028] In the new radio system 5G-NR, for each numerology and carrier, a resource grid of subcarriers and OFDM symbols is defined for the uplink and downlink, respectively. Each element in the resource grid is called a resource element and is identified based on a frequency index in the frequency domain and a symbol position in the time domain. A tentative definition is currently provided in 3GPP TS 38.211 v1.0.0, which is incorporated herein by reference.

[0029] LTE system information acquisition

[0030] In LTE, system information is structured by system information blocks (SIBs), each of which contains a set of functionally related parameters. The MIB (master information block) contains a limited number of the most frequently transmitted parameters that are essential for the UE's initial access to the network. There are different types of system information blocks SIB1 to SIB18 currently defined in LTE to convey additional parameters: for example, SIB1 contains parameters necessary to determine whether a cell is suitable for cell selection as well as information about the time domain scheduling of the other SIBs, and for example, SIB2 contains common and shared channel information.

[0031] Three types of RRC (Radio Resource Control) can be used to transfer system information, MIB, SIB1 message, and SI message. SIBs other than SIB1 are transmitted within system information messages (SI messages), and there are several SI messages, and an SIB message contains one or more SIBs with the same scheduling requirements (e.g., the same transmission periodicity). Depending on the content of the SI message, the UE needs to obtain different SI messages in idle and connected states, for example, the third SI message (inter-frequency cell reselection information) for SIB5 needs to be obtained only in idle state.

[0032] Further information regarding system information can be found in section 5.2 "System information" of 3GPP Technical Specification TS 36.331 v14.4.0, the entire contents of which are incorporated herein by reference.

[0033] NR system information acquisition

[0034] In 5G NR, it is currently assumed (though not yet finalized) that system information will generally be divided into minimum system information and other system information. Minimum system information is periodically broadcast and includes basic information required for initial access to a cell (e.g., system frame number, list of PLMNs, cell ID, cell camping parameters, RACH parameters, etc.). Minimum system information may further include information for obtaining any other SI broadcast periodically or provided on request, e.g., appropriate scheduling information for the above. Scheduling information may include, for example, SIB type, validity information, SI periodicity, and SI window information, as needed. Correspondingly, other system information will encompass everything not broadcast in the minimum system information, e.g., cell reselection neighbor cell information.

[0035] Other SI may be broadcast or provided in a specified manner, either triggered by the network or upon request from the UE, as shown in Figure 4. Other SI may be broadcast with configurable periodicity and for a specific duration. It is a network decision whether other SI is broadcast or delivered via specified UE-specific RRC signaling.

[0036] For other SI that is actually required by the UE, before the UE sends a request for the other SI, the UE needs to know whether the other SI is available in the cell and whether the other SI is broadcast. For a UE in RRC_CONNECTED state, designated RRC signaling can be used, for example, for requesting and delivering the other SI.

[0037] In legacy LTE, a UE is required to (re)acquire system information whenever a cell change occurs, and the UE is also required to reacquire all system information whenever the system information changes (e.g., as indicated by paging or an incremented, i.e., changed, value tag). For the new 5G NR system, it is generally desirable to reduce the need to reacquire system information by identifying stored system information with a unique index / identifier that is broadcast along with the minimum system information. Some system information valid in one cell may also be valid in other cells. For example, common radio resource configuration, access class barring information, UL carrier frequency and bandwidth, and MBSFN (Multimedia Broadcast Single-Frequency Network) subframe configuration may be valid across multiple neighboring cells.

[0038] However, there is no final agreement on 5G NR system information.

[0039] RACH Procedure

[0040] Final agreement has not been reached on the 5G NR Random Access Channel (RACH) procedure. As described in section 9.2 of TR 38.804 v14.0.0, which is incorporated herein by reference, the NR RACH procedure may support both contention-based and contention-free random access in the same or similar manner as defined for LTE. The NR RACH procedure design will also support flexible message 3 sizes, similar to LTE.

[0041] The LTE RACH procedure is described in more detail below with reference to Figures 5 and 6. An LTE mobile terminal can only be scheduled for uplink transmission if the mobile terminal's uplink transmission is time synchronized. Therefore, the random access channel (RACH) procedure plays an important role as an interface between an asynchronous mobile terminal (UE) and orthogonal uplink radio access transmission. For example, random access in LTE is used to achieve uplink time synchronization for user equipment that has either not yet acquired or has lost uplink synchronization. Once the user equipment achieves uplink synchronization, the eNodeB can schedule uplink transmission resources for the user equipment. One scenario related to random access is when the user equipment is in the RRC_CONNECTED state and the user equipment handovers from its current serving cell to a new target cell, the handover involves performing a random access procedure to achieve uplink time synchronization at the target cell.

[0042] In LTE, two types of random access procedures are provided, granting access either contention-based, i.e., with an inherent risk of collision, or contention-free (non-contention-based). A detailed description of the LTE random access procedure can also be found in 3GPP TS 36.321, section 5.1.v14.1.0, which is incorporated herein by reference.

[0043] In the following, the contention-based random access procedure for LTE is described in more detail with reference to Figure 5. The procedure consists of four "steps". First, a user equipment transmits a random access preamble to the eNodeB on the Physical Random Access Channel (PRACH) (i.e., message 1 of the RACH procedure). After detecting the RACH preamble, the eNodeB sends a Random Access Response (RAR) message (message 2 of the RACH procedure) on the Physical Downlink Shared Channel (PDSCH) addressed on the PDCCH with the (random access) RA-RNTI identifying the time-frequency slot in which the preamble was detected. If multiple user equipments transmit the same RACH preamble on the same PRACH resource, also known as a collision, they will receive the same random access response message. The RAR message may carry a timing alignment command (TA command) for synchronizing the detected RACH preamble with subsequent uplink transmissions, an initial uplink resource allocation (grant) for transmitting the first scheduled transmission, and the assignment of a Temporary Cell Radio Network Temporary Identifier (T-CRNTI) that is used by the eNodeB to address the mobile terminal(s) whose RACH preamble was detected until the RACH procedure is over, since the "true" identity of the mobile terminal is not yet known to the eNodeB at this point.

[0044] The user equipment monitors the PDCCH for a random access response message within a given time window configured by the eNodeB. In response to the RAR message received from the eNodeB, the user equipment transmits a first scheduled uplink transmission on the radio resources allocated by the grant in the random access response. This scheduled uplink transmission carries the actual random access procedure message, such as an RRC connection request or a buffer status report.

[0045] If a preamble collision occurs at the beginning of the RACH procedure, i.e., multiple user equipments send the same preamble on the same PRACH resource, the colliding user equipments receive the same T-CRNTI in the random access response and also collide on the same uplink resource when transmitting their scheduled transmissions in the third step of the RACH procedure. If the scheduled transmission from one user equipment is successfully decoded by the eNodeB, the contention for the other user equipment(s) remains unresolved. To resolve this type of contention, the eNodeB sends a contention resolution message (fourth message) addressed to the C-RNTI or temporary C-RNTI.

[0046] Figure 6 shows a contention-free random access procedure in 3GPP LTE, which is simplified compared to the contention-based random access procedure. In a first step, the eNodeB provides the user equipment with a preamble to use for random access, without risk of collision, i.e., multiple user equipments do not transmit the same preamble. In response, the user equipment then transmits the preamble signaled by the eNodeB on the PRACH resource in the uplink. Since contention-free random access avoids the case where multiple UEs transmit the same preamble, the contention-free random access procedure essentially ends after the UE successfully receives a random access response.

[0047] Therefore, a similar or identical RACH procedure to that just described in connection with Figures 5 and 6 may be adopted in the future for the new 5G radio technology. However, 3GPP is also considering a two-step RACH procedure for 5G NR, in which message 1, corresponding to messages 1 and 3 of the four-step RACH procedure, is transmitted first. The gNB would then respond with message 2, corresponding to messages 2 and 4 of the LTE RACH procedure. Due to the reduced message exchange, the latency of the two-step RACH procedure may be reduced compared to the four-step RACH procedure. The radio resources for the messages are optionally configured by the network.

[0048] Furthermore, while 3GPP generally agrees that NR communications should support random access prioritization, they have not agreed on the details of how this can be achieved in detail, which may involve the possibility of distinguishing between different backoff parameters and power ramping values.

[0049] In contrast, in an LTE system, the UE basically performs the same random access procedure using the same set of configured parameters, such as a common back-off value, a common power ramping parameter, and radio resources of the PRACH (Physical Random Access Channel). Therefore, the UE performs the random access procedure without any consideration of the purpose of the access request, i.e., the reason for performing the random access procedure in the first place.

[0050] In contrast, prioritization of different UE random access procedures is motivated by the need to support a wider set of service requirements in future NR systems and also by the desire to improve system robustness. More specifically, different user services currently handled by a UE can also benefit from random access prioritization. For example, a random access triggered for a URLLC service may benefit from faster access with lower latency than is required for a random access procedure triggered in connection with an eMBB service.

[0051] Furthermore, different types of random access (RA) events have different access latency requirements, such that a random access request triggered by a UE due to a particular RA event has higher priority than other access requests. For example, an RA event triggered by an RRC connection re-establishment shall be processed with a shorter latency than an RA event triggered by, for example, a UE attempting to gain initial access. Similarly, a UE in RRC_Connected state attempting to synchronize using a random access procedure may also be given higher priority than a UE in RRC_Idle state attempting to gain initial access using, for example, random access.

[0052] Moreover, random access requests triggered by certain RA events (e.g., random access event 5, see below) may require further specific configuration parameters, such as a different numerology for sending the second message MSG2 from the gNB to the UE (see FIG. 5). Another aspect of random access prioritization may be that certain premium users require faster access and a higher success rate compared to other general users (e.g., higher QoS (Quality of Service) parameters compared to other general users).

[0053] The following random access events are currently defined: ● (Event 1): Initial access from RRC_IDLE, ● (Event 2) : RRC connection re-establishment procedure, ● (Event 3) :Handover, ● (Event 4) DL data arrival during RRC_CONNECTED requiring a random access procedure, e.g. when the UL synchronization status is "unsynchronized"; ● (Event 5) : UL data arrival during RRC_CONNECTED requiring a random access procedure, e.g. when the UL synchronization status is "unsynchronized" or there are no available PUCCH resources for SR. ● (Event 6) : Transition from RRC_INACTIVE to RRC_CONNECTED ● (Event 7) :Beam recovery

[0054] Events 1 to 6, which trigger the random access procedure, are known from LTE systems, but the introduction of event 7 (beam recovery) for 5G NR systems is currently under discussion.

[0055] Although random access prioritization has been generally agreed upon by 3GPP, detailed solutions are not yet available or proposed. Correspondingly, there is a need for an improved random access procedure that allows for prioritization.

[0056] Detailed Description of the Disclosure

[0057] In the following, UEs, base stations, and procedures that meet this need are described for new radio access technologies envisioned for 5G mobile communication systems. Different implementations and variations are also described. The following detailed disclosure is facilitated by, and may be based at least in part on, the discussion and findings set forth in the previous section, "Basis of the Disclosure."

[0058] However, in general, only a few things are actually agreed upon regarding 5G cellular communication systems, so that in the following a number of assumptions need to be made in order to be able to explain the principles underlying the present disclosure in a clear and understandable manner. However, these assumptions should be understood as merely examples, without limiting the scope of the present disclosure. Those skilled in the art will recognize that the principles presented in the following disclosure and in the claims can be applied to different scenarios and in ways not explicitly described herein.

[0059] Furthermore, the terms used below, such as procedures, entities, layers, and layers, are closely related to the terminology used in the LTE / LTE-A system or the current discussion items of 3GPP 5G, even though the specific terminology used in connection with the new radio access technology of the upcoming 3GPP 5G communication system has not yet been fully determined. Therefore, the terminology may change during the 3GPP standardization phase without affecting the functionality of the embodiments of the present invention. As a result, those skilled in the art will understand that the scope of the present invention and its protection is not limited to the specific terminology used illustratively herein due to the lack of newer or finally agreed-upon terminology, but is more broadly understood in terms of the functions and concepts underlying the functions and principles of the present disclosure.

[0060] for example, Mobile station or Mobile Node or User terminal or User Equipment (UE)A node is a physical entity (physical node) in a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a given set of functions to other functional entities in the same or another node or network. A node may have one or more interfaces that attach the node to a communication facility or medium through which the node may communicate. Similarly, a network entity may have logical interfaces that attach the functional entity to a communication facility or medium through which the network entity may communicate with other functional entities or corresponding nodes.

[0061] The terms "base station" or "radio base station" are used herein to refer to a physical entity in a communication network. Similar to a mobile station, a base station may have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predetermined set of functions to other functional entities of the same or another node or network. A physical entity performs several control tasks for communication devices, including one or more scheduling and configuration tasks. It should be noted that the functionality of a base station and a communication device may also be integrated within a single device. For example, a mobile terminal may also implement the functionality of a base station for other terminals. The terminology used in LTE is eNB (or eNodeB), whereas the terminology currently used for 5G NR is gNB.

[0062] 7 is a general, simplified, exemplary block diagram of a user equipment (also referred to as a communication device) and a scheduling device (herein assumed to be located in a base station, e.g., an LTE eNB or a 5G NR gNB). The UE and eNB / gNB communicate with each other over a (wireless) physical channel using their respective transceivers.

[0063] A communication device may include a transceiver and a processing circuit. The transceiver, in turn, may include a receiver and a transmitter. The processing circuit may be hardware consisting of one or more components, such as one or more processors or several LSIs. Between the transceiver and the processing circuit, there is an input / output point (or node), through which the processing circuit, when in operation, can control the transceiver, i.e., control the receiver and / or transmitter, and exchange receive / transmit data. The transceiver may include an RF (radio frequency) front end, including one or more antennas, amplifiers, RF modulators / demodulators, etc. The processing circuit may implement control tasks, such as controlling the transceiver to transmit user data and control data provided by the processing circuit and / or receive user data and control data that are further processed by the processing circuit. The processing circuit may also be responsible for performing processes such as judgments, decisions, calculations, measurements, etc. The transmitter may be responsible for performing transmission processing and other related processes. The receiver may be responsible for receiving processing and other related processes.

[0064] Therefore, in this case, as will become clear from the following description of different embodiments and variants thereof, the processor can exemplarily be configured to determine certain transmission parameters that are necessary for transmitting messages of the RACH procedure. Another example refers to then configuring the transmitter to be able to transmit messages of the RACH procedure, for example using the transmission parameters determined by the processor. Conversely, the receiver can then be configured to be able to receive messages of the RACH procedure.

[0065] In the following, a simple exemplary scenario is assumed: As illustrated in Figure 8, a UE is assumed to be located in the coverage area of ​​radio cell 1 controlled by gNB1. There are neighboring radio cells 2, 3, and 4 controlled by gNB2, gNB3, and gNB4, respectively.

[0066] One important procedure that is performed for various reasons is the random access channel (RACH) procedure (which may also be referred to as a random access procedure or RA procedure) between the UE and the gNB. Details regarding the random access procedures known from LTE and currently being discussed for 5G NR are provided in the previous sections, to which reference is made. For the purposes of describing and explaining the concepts underlying the embodiments presented below, a four-step contention-based random access procedure is exemplarily assumed. However, it should be noted that this concept can also be applied to different random access procedures, such as a shorter two-step procedure or a contention-free random access procedure.

[0067] Embodiment 1

[0068] In the following an improved random access procedure is described according to a first embodiment which allows differentiation between the PRACH resources used by the UE and therefore allows prioritizing the random access procedure as needed.

[0069] In this regard, prioritization of random access procedures allows the backoff time and / or transmit power values ​​used by the UE for the random access procedure to be adapted to better reflect (and thus facilitate meeting specific requirements for) the priority imposed, for example, by the UE or by the random access event that triggers the random access. The backoff parameters are used to determine the period of time the UE needs to wait between a previous (possibly unsuccessful) random access procedure and the initiation of a new random access procedure (by transmitting a first random access message with a preamble). The backoff parameters are provided to the UE by the gNB, for example, in the event of a collision being detected at the gNB, i.e., when several UEs transmit the same preamble to the gNB using the same PRACH resource. Backoff parameters are known in LTE, for example, in the corresponding sections 5.1.4 and 7.2 of TS 36.321 v14.3.0, which is incorporated herein by reference. The transmission power value indicates the value based on which the UE decides with what power it can transmit the first random access message of the random access procedure to the gNB, and therefore affects the robustness of the scheduled transmission itself and also the chances of success in the event of a colliding RACH procedure between several UEs.

[0070] Consequently, prioritization of random access procedures is particularly useful in cases where collisions occur between different UEs using the same random access resource. In those cases where the gNB identifies that collisions between random access procedures are performed by different UEs, the gNB may prioritize further execution of the random access procedures of different UEs by selecting and allocating appropriate backoffs to the different UEs.

[0071] According to this embodiment, the UE is involved in prioritizing the random access procedure by selecting an appropriate PRACH resource (indicating a prioritization criterion), and the gNB can then differentiate between the PRACH resources in order to provide the UE with back-off parameters to prioritize further random accesses. To implement the UE selection and gNB decision, random access configuration information shall be available on both the UE and gNB sides, associating specific PRACH resources (also referred to as random access transmission parameters) with specific prioritization criteria (e.g., circumstances based on which random accesses should be prioritized).

[0072] For example, the random access transmission parameters are: a random access preamble sequence transmitted together with the random access message; The time and frequency of radio channel resources used by the UE when sending a random access message to the gNB; and a transmit power value to be used by the UE when transmitting a random access message to the gNB.

[0073] An exemplary simplified illustration of these random access transmission parameters is provided in Figure 9. As is apparent from Figure 9, by way of example, the PRACH resources are assumed to be distinguishable based on the time (T1, T2, T3, T4) and frequency (F1, F2, F3, F4, F5) of the radio resources, as well as by the preamble sequence (S1, S2, S3) transmitted by the UE with the first RA message (the third dimension in the diagram of Figure 9). The reader should recognize that the illustration and distinguishing parameters are merely exemplary, and that smaller or larger levels of time, frequency, and sequence are equally possible.

[0074] Although the transmit power is a parameter of the RA message transmission, the gNB may not reliably distinguish one PRACH resource from another. As mentioned above, the transmit power can be used to prioritize one random access procedure over another.

[0075] Similarly, the frequency band available for PRACH transmissions can be divided into frequency ranges that are differentiated for purposes of, for example, random access prioritization, while different time instances (e.g., subframes within a radio frame) can be used to differentiate the transmission of random access messages for purposes of random access prioritization.

[0076] In LTE, there are 64 different preamble sequences defined, and more than 64 preamble sequences may be defined in the future for 5G NR. As a result, certain preamble sequences can be reserved for certain prioritization criteria (or combinations thereof), and several preamble sequences can be grouped together and associated with certain prioritization criteria (or combinations thereof).

[0077] According to one example, the differentiation of PRACH resources may be based solely on the frequency of the radio resources used for transmitting the first random access message, such that a particular frequency or frequency range is uniquely associated / reserved with a particular prioritization criterion (e.g., one or more random access events). In a further similar example, the differentiation of PRACH resources may be based solely on the time of the radio resources used for transmitting the first random access message, such that a particular time instance is uniquely associated / reserved with a particular prioritization criterion (e.g., one or more random access events). As a further example, the differentiation of PRACH resources may be based solely on the preamble sequences transmitted with the first random access message, such that one or more preamble sequences are uniquely associated / reserved with a particular prioritization criterion (e.g., one or more random access events).

[0078] While the above example distinguishes PRACH resources based on only one of the dimensions, it is equally possible that different combinations of dimensions are appropriately defined to distinguish PRACH resources. This is particularly useful in those cases where fine distinctions in prioritization criteria are required. In that case, PRACH resource distinctions can use multiple dimensions to enable many different prioritizations. For example, a specific group of preamble sequences within a specific frequency range may be associated with a combination of prioritization criteria (such as a random access event combined with the use of a service). Another exemplary definition of PRACH resource partitioning is that the set of PRACH resources reserved for a specific random access event (Event 2, RRC Connection Re-establishment) is further divided based on user services (e.g., distinguishing between all three currently defined user services, or only one or two). As a result, each subset of PRACH resources defined in this way is associated with a combination of random access event(s) and user service(s).

[0079] Furthermore, random access, a random access event that triggers the sending of a random access message; a user service currently being used by the user equipment, the user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and contractual terms, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and • Subcarrier spacing, which defines the frequency distance between two consecutive subcarriers; and • Prioritization can be based on several different criteria, including, or any combination thereof.

[0080] For example, a random access procedure triggered by a specific random access event can be prioritized higher than random access procedures triggered by other random access event(s). One example is that RA event 1 (i.e., initial access of a UE in RRC_IDLE state) can be prioritized lower than RA event 4 (i.e., downlink data arrival), for example, by having a high (large) backoff parameter and / or a low transmit power. Similarly, RA event 2 (RRC connection re-establishment) can be prioritized higher than RA event 1. For example, all or only some of the RA events can be differentiated from each other for RA prioritization. Another example is that random access events 6 and 7 can be prioritized higher regardless of the user service. According to another example for a specific user service such as URLLC, random access events 2, 3, and 4 have higher priority, while random access events 6 and 7 have lower priority. According to another example for a specific user service such as eMBB, random access events 2 and 3 have higher priority, while random access events 4 and 5 have lower priority. According to another example, random access event 1 may have a low priority, further independent of the user service for which the random access procedure is performed.

[0081] Furthermore, the prioritization of random access procedures can be based on the user service, i.e., whether data communication by the UE is currently performed for URLLC, eMBB, or mMTC. As explained in detail in the previous pages, each user service is suited to different data transmission scenarios with different requirements, e.g., URLLC requires very low latency, while eMBB is not latency-critical but requires high peak data rates, etc. Therefore, to facilitate meeting the latency requirements of the URLLC user service provided to the UE, it is possible to prioritize the random access procedure for URLLC over the random access procedures for eMBB or mMTC. For example, all or only some of the user services can be differentiated from one another for RA prioritization.

[0082] User equipment typically operates under a user contract with a network operator, which may affect the general provision of user services to that UE compared to other UEs. For example, a premium user typically pays a higher amount for a premium user contract and may receive a higher quality of service than a standard user who pays a correspondingly lower amount for a standard user contract. This may also affect the priority with which random access procedures are performed between the UE and the gNB. For example, the back-off time value used for the random access procedure for premium UEs may be shorter than that for random access procedures for normal UEs, and / or the transmit power used for random access message transmission may be higher. For example, all or only some of the possible contractual provisions may be differentiated from each other for RA prioritization. QoS parameters for a user may be exchanged between the MME and the gNB, for example, via the S1 interface (e.g., using a SIAP Initial Context Setup Request similar or identical to that defined in TS 36.413 clause 8.3.1.2). Thus, the gNB knows the QoS values ​​for the UE. When the UE sends a RACH request message, the gNB can therefore check the QoS parameters and, based on this QoS, calculate an appropriate back-off value for the UE. For high QoS (premium users), the gNB sets low back-off parameters, while for general / standard users, the gNB sets high back-off parameters.

[0083] Subcarrier spacing may or may not have a direct relationship to user services. As described in previous pages, different numerologies with different subcarrier spacings are currently defined for different user services to be supported by 5G NR systems. A subcarrier spacing of 15 kHz is currently assumed for mMTC, a subcarrier spacing of 30 kHz for eMBB, and a subcarrier spacing of 60 kHz for URLLC. However, multiple subcarrier spacings may be used for a specific user service. Instead of or in addition to prioritization based on user services, it is also possible to prioritize the random access procedure based on which subcarrier spacing is used to transmit the first random access message. A subcarrier spacing of 60 kHz, which has a very short symbol duration, may be prioritized higher than a subcarrier spacing of 15 kHz, which has a relatively long symbol duration. For example, all or only some of the possible subcarrier spacings may be distinguished from each other for RA prioritization.

[0084] The above list of criteria is not exhaustive, and additional criteria not explicitly mentioned above may also be used to implement the discussed random access prioritization.

[0085] Random access prioritization can be based on each of these single criteria alone, but any meaningful combination of them can also serve to prioritize random access procedures amongst one another. Only a few examples of possible combinations are given below, but it should be clear to the reader that other combinations of criteria are equally possible, even if not explicitly stated.

[0086] For example, a combination of specific random access event(s) for specific user service(s) can be used to differentiate RA prioritization. For example, for specific user services such as URLLC or eMBB, the random access prioritization may be further differentiated based on the random access event that triggered the transmission of the random access message (i.e., triggered the random access procedure). According to one example, even when referring to the same service, eMBB, the random access prioritization for RA events 2 (RRC connection re-establishment procedure) and 3 (handover) may be different from RA events 4 and 5 (downlink and uplink data arrival in an unsynchronized state, respectively).

[0087] Moreover, although mentioned above, it is not necessary to be able to uniquely distinguish all different prioritizations, but certain prioritization criteria can be grouped together so that only groups of prioritization criteria can be distinguished on the gNB side. For example, several random access events can be grouped together (e.g., random access events 2, 3, 4, 5), assuming that in some cases they will have similar priorities for the corresponding random access procedures. By grouping certain prioritization criteria, the number of different sets of PRACH resources required is reduced, since overall only a small number of prioritization criteria (or combinations thereof) need to be distinguished. Another example is grouping different contractual commitments together as needed, for example, grouping premium users with prioritized users or users under a group as opposed to standard users.

[0088] One general idea underlying the first embodiment is to provide the gNB with more detailed information about the random access procedure and the communicating UEs in an efficient manner, so that the prioritization can be controlled by the gNB. Instead of using additional bits to convey specific information to the gNB, the set of available PRACH resources is divided so that the UE selects PRACH resources according to the triggered random access procedure and / or the UE, and then the gNB can deduce information from the selected PRACH resources used by the UE to transmit the first RA message. In other words, the UE uses different PRACH resources (i.e., parameters for transmitting the first random access message) for transmitting the first random access message so that these different prioritizations and combinations thereof can be distinguished from each other. The gNB is able to distinguish the PRACH resources used by the UE and therefore determine the prioritization criteria involved in that particular random access procedure for each different random access event that triggered the transmission of an RA message, in one example, the UE first determines and then uses a different PRACH resource (e.g., a different frequency or time), which allows the gNB to unambiguously determine which random access event triggered the random access procedure by the UE.

[0089] The necessary information (e.g., also referred to as random access configuration information) for how the UE should select an appropriate PRACH resource based on the prioritization criteria, and conversely, how the gNB determines the prioritization criteria from the selected PRACH resources, is available to both the UE and the gNB. One possible way is for the necessary information to be defined by 3GPP technical specifications and thus effectively hard-coded into the UE's operating system. In this respect, no information exchange is required between the UE and the gNB. However, this does not allow for greater flexibility in how the random access procedure is prioritized.

[0090] Another possible method is for the gNB to provide the UE with the necessary information, for example in the system information. This also has the benefit that the PRACH parameterization (i.e., PRACH resource differentiation) can be cell-specific and therefore can vary from cell to cell. Correspondingly, when the UE moves from the source gNB to the target gNB, new PRACH configuration information is received by the UE either via the system information in the new radio cell or via an already-taken RRC connection reconfiguration message.

[0091] As currently tentatively envisioned in 5G (see also previous discussion), system information can be provided either in minimum SI, other SI, and / or on-demand SI messages, but also in designated RRC messages directly addressed to the UE(s). Consequently, any of these messages, or a combination thereof, can be used to convey RA configuration information to the UE. For example, a minimum SI message can be used to provide either all or only part of the random access configuration information to the UE in the radio cell, while the remaining part of the random access configuration information can be provided to the UE using, for example, other SI, on-demand SI, or separately in an RRC message addressed to the UE. In a further variant, RA configuration information corresponding to important prioritization (e.g., for RA event 1, initial access) can be transmitted in minimum SI, while RA configuration information for less important prioritization can be provided to the UE differently. For example, RA configuration information for random access events 2, 5, and 6 is conveyed by on-demand system information. On the other hand, for example, RA configuration information for RA events 4 and 7 (low latency required) can be conveyed by a designated RRC message (such as an RRC Connection Reconfiguration message).

[0092] This reduces the overhead caused by minimum system information transmissions, which are assumed to occur periodically or fairly frequently. Moreover, by using, for example, on-demand system information or even designated RRC messages, it is possible to provide different configuration information to different UEs and thus potentially implement UE-specific prioritization.

[0093] In one exemplary variant, the UE and the gNB define random access configuration information such that for every possible triggered random access procedure, the UE can derive which PRACH resource to use, and the gNB can conversely derive from the PRACH resources used whether and how to prioritize the random access procedure, whereas in other cases that are not or not yet covered by the available random access configuration information, the UE can simply use default or common PRACH resources.

[0094] In this embodiment, the UE can simply determine the transmit power when performing the enhanced random access procedure without reference to any of the prioritization criteria described above, which is similar to how current LTE RACH procedures work.

[0095] On the other hand, the random access prioritization according to the first embodiment can be further implemented, additionally or independently, by determining in the UE an appropriate transmission power to be used for transmitting the first RA message of the RA procedure. Once the RA transmission parameters have been determined in the UE, the UE needs to decide at what radio power to transmit the RA message. This decision can be made based on any of the above-mentioned prioritization criteria or a combination thereof, in a manner similar to how the UE determines the PRACH resources (distinguishable by the UE). A corresponding transmission power table can be created by the UE to associate specific transmission power values ​​with specific prioritization criteria, thus enabling the UE to determine for each triggered random access procedure an appropriate transmission power to be used when transmitting the first RA message of the RA procedure.

[0096] One simple exemplary transmit power table that implements prioritization based solely on random access events is as follows:

[0097] [Table 1]

[0098] Another simple exemplary transmit power table that implements prioritization based solely on user service is as follows:

[0099] [Table 2]

[0100] A more detailed transmit power table distinguishing between some specific combinations of random access events, user services, and contract status is as follows:

[0101] [Table 3]

[0102] As is evident from the above table, different user services (eg URLLC and eMBB) may therefore have different transmit power parameters for the same RA event (eg RA events 2 and 3).

[0103] In a further alternative, instead of associating a power parameter with a particular prioritization criterion, a power ramping parameter can be associated with each set of PRACH resources (which are then associated with a particular prioritization criterion).

[0104] The necessary information for the transmit power table is made available to the UE. Several options exist as to how this can be achieved. As described in a similar manner for the backoff index table (see there for details), the transmit power table may be defined, for example, in a 3GPP technical specification or transmitted by the gNB to the UE, for example, using system information broadcast in the gNB's radio cell. The transmit power table may be provided either in a minimum SI, and / or other SI, and / or on-demand SI message, and / or in a designated RRC message directly addressed to the UE(s). Consequently, any of these messages, or a combination thereof, may be used to convey RA configuration information to the UE.

[0105] Increasing the transmission power for random access message transmissions can also be implemented by further variants of this embodiment, as is known from LTE. Specifically, the transmission power can be continuously increased with each failed RA message transmission based on a given transmission power step size. In the above case, assuming a random access procedure for RA event 1 as an example, the UE thus starts transmitting the first RA message with a transmission power of -120 dbm, and in case of a random access failure, the UE uses a transmission power of -116 dbm for the second attempt to transmit the RA message, -112 dbm for the third attempt thereafter, etc. (assuming a 4 db step size).

[0106] A simplified exemplary illustration of UE behavior involved in the enhanced random access procedure of this embodiment and variations thereof, as described herein, is presented in the form of a sequence diagram in FIG. 10 . Furthermore, a simplified exemplary illustration of gNB behavior involved in the enhanced random access procedure of this embodiment and variations thereof, as described herein, is presented in the form of a sequence diagram in FIG. 11 . For ease of illustration only, it is illustratively assumed that the prioritization of the random access procedure is based solely on the random access event. A further exemplary assumption is that the UE has received appropriate random access configuration information from the base station according to any of the examples given above. It is then further assumed that any of multiple random access events ultimately triggers the random access procedure at the UE. Based on the previously received RA configuration information and considering the random access event that triggers the random access procedure, the UE can then determine corresponding random access transmission parameters (e.g., distinguishable only by frequency, see also one of the various examples above), which are then used by the UE to transmit a first random access message to the gNB.

[0107] The gNB is correspondingly able to receive a random access message from the UE based on the random access transmission parameters used and based on the corresponding random access configuration information and determine which random access event triggered the random access procedure (i.e., the transmission of the random access message). Depending on the random access event and its associated priority, the gNB determines back-off parameters accordingly and provides the determined back-off parameters to the UE in a random access response message.

[0108] As briefly mentioned above, the gNB selects appropriate backoff parameters based on the random access transmission parameters and provides the selected backoff parameters to the UE using a random access response message. One possibility for transmitting the backoff parameters is to reuse the corresponding backoff parameters defined for the LTE RACH procedure, which encodes the backoff index with 4 bits, allowing for 16 different backoff indices. The current definition is provided in 3GPP TS 36.321 v14.3.0 section 7.2 and is illustrated below:

[0109] [Table 4]

[0110] As is evident from the above, backoff index values ​​13, 14, and 15 are currently reserved and may instead be used to encode very low backoff values ​​that allow further prioritization, such as 0.5 ms, 1 ms, 2 ms, etc. A correspondingly adapted exemplary backoff time table may be defined as follows:

[0111] [Table 5]

[0112] For example, the gNB may indicate 0.5 ms, 1 ms, or 2 ms when random access is triggered for URLLC due to random access event 5. For example, a higher backoff parameter value (e.g., 10 ms) may be indicated by the gNB when random access is triggered for eMBB due to random access event 5.

[0113] On the other hand, instead of reusing the backoff index definition of LTE, an entirely different backoff time table can be defined for 5G NR and the backoff index can be coded using more or less than 4 bits.

[0114] According to a further variant of this embodiment, the selection of the PRACH resource can also be based on the subcarrier spacing that the gNB should use to transmit the random access response message. More specifically, a UE in a connected state typically monitors the PDCCH / PDSCH using a corresponding subcarrier spacing (e.g., depending on the user service, as explained above) and, upon transmitting a first random access message, monitors the radio resources during the RAR reception window to receive a random access response message from the gNB. Typically, the random access response message is transmitted by the gNB using a reference numerology, and therefore a reference subcarrier spacing, regardless of the user service that the UE is currently using. In such a situation, the UE is thus required to process and monitor two different numerologies simultaneously, which increases the complexity of the UE. To avoid this excessive complexity, according to a further variant of the embodiment, the gNB can be provided with information about which subcarrier spacing is currently being used by the UE, so that the gNB uses the same numerology corresponding to the transmission of the random access response message to the UE instead of using the reference numerology.

[0115] Correspondingly, the PRACH resources available for the UE to transmit the random access message may be further divided based on subcarrier spacing, and the UE's use of these specific PRACH resources enables the gNB to estimate which subcarrier spacing the gNB should use to transmit the random access response message. When in operation, the UE thus determines the PRACH resources based on the subcarrier spacing that the gNB should use to transmit the random access response message, and transmits the random access message to the gNB using these determined PRACH resources.

[0116] This improved variant of the embodiment may be for example used for one of the random access events, such as event 4 or 5 related to downlink and uplink transmission of data, where the UE is already connected and may already be communicating based on a numerology (i.e., subcarrier spacing) different from the reference numerology (i.e., reference subcarrier spacing). Since the UE is not in connected mode in this case and therefore is not yet monitoring based on a specific subcarrier spacing of the user service, the need for initial access by the UE is reduced, and in this case the gNB may transmit a random access response message using the reference numerology (i.e., reference subcarrier spacing).

[0117] For example, the set of PRACH resources reserved for random access event 4 is further sub-divided based on the possible subcarrier spacing, thus generating three subsets for random access event 4 combinations with subcarrier spacing of 15, 30, or 60 kHz, respectively.

[0118] In the same manner as already described for the previous case, the random access configuration information needed to differentiate based on the subcarrier spacing described above can be provided to the UE, for example using system information (e.g. minimum SI, other SI, SI on request, specified RRC messages, see previous page for details).

[0119] According to a further improved variant of the first embodiment, prioritization of the random access procedure by using different back-off parameters can also be implemented in the UE in certain scenarios. More specifically, as explained above, the gNB selects the appropriate back-off parameters based on the selected PRACH resources, which are considered as indicating the prioritization criteria on the UE side.

[0120] However, as explained above, a variant of the first embodiment allows for grouping of specific prioritization criteria, such as specific random access events. In the above exemplary cases, it is not possible for the gNB to distinguish between random access events within a group of random access events that actually triggered the random access procedure in the UE based on the PRACH resources used. However, in these cases, prioritization of random access procedures within a group of random access events can be achieved on the UE side, which knows the actual random access event that triggered the random access procedure.

[0121] In response, the UE determines PRACH resources associated with a group of random access events, including the random access event that actually triggers the random access procedure. These determined PRACH resources are then used by the UE to transmit a first random access message to the gNB, which can then derive the corresponding group of random access events from the used PRACH resources and thus determine appropriate back-off parameters. The dependent back-off parameters can then be conveyed to the UE using a random access response message.

[0122] According to this variation of the first embodiment, the UE may determine the back-off time value based on the received back-off parameters, but further taking into account the actual random access event that triggered the random access procedure. The UE is therefore able to further prioritize the random access procedure based on the actual random access event that triggered the random access procedure, in addition to any prioritization performed by the gNB.

[0123] A similar approach can also be used for scenarios where there is no PRACH resource differentiation performed for specific prioritization criteria. For example, in a variant of the first embodiment, the prioritization of random access procedures by the gNB is performed only for specific prioritization criteria, such as specific random access events or user services. For other prioritization criteria, a common PRACH resource is used by the UE that does not encode any further information, thus not allowing the gNB to derive any information from the common PRACH resource. For those cases where prioritization is not possible on the gNB side, the prioritization of random access procedures can nevertheless be implemented on the UE side, which already has the necessary information, without the need to subdivide the PRACH resource to encode the information transmitted to the gNB. For example, random access procedures triggered by RA events 1 and 2 can use a common PRACH resource, while random access procedures triggered by other random access events can use designated PRACH resources as described in connection with the improved random access procedure above. In the case where common PRACH resources are used by UEs, as explained above, prioritization of the random access procedure can, in one example, be achieved on the UE side, which knows, for example, the prioritization criteria used (random access events and / or user services) and can therefore select the back-off parameters (and transmit power).

[0124] Embodiment 2

[0125] In a second embodiment, a further implementation of prioritization of random access procedures is described. Conceptually, prioritization is handled on the UE side as much as possible, thus eliminating the need to inform the gNB of details of triggered random access procedures compared to the solution provided in embodiment 1. A similar approach has been described in connection with certain variants of the first embodiment.

[0126] Instead of distinguishing between different PRACH resources (i.e., random access transmission parameters) to provide the gNB with information about prioritization criteria, e.g., random access events, we first assume that the UEs use a common PRACH resource to transmit the first random access message of the random access procedure to the gNB. This approach is in this case the same as or very similar to the current LTE random access procedure, where all UEs perform the random access procedure with the same set of configured transmission parameters, which does not allow the receiving side to distinguish between, e.g., different random access events (different users can still be distinguished, but not identified, based on the preamble sequence transmitted with the random access message).

[0127] On the other hand, prioritization on the UE side can be implemented by distinguishing between prioritization criteria (e.g., random access events, contractual agreements, user services, subcarrier spacing, as emphasized and discussed in embodiment 1) and appropriately selecting corresponding backoff time values ​​and / or transmission powers that reflect the prioritization associated with the corresponding prioritization criteria.

[0128] More specifically, for the second embodiment, a backoff time table (also referred to as a backoff index table) is used in the UE to enable the implementation of random access prioritization, the backoff time table associating different backoff time values ​​with both a backoff index (received from the gNB) and a corresponding prioritization criterion (or combination of prioritization criteria). In a similar manner as described for the first embodiment, the prioritization of the random access procedure can be performed by: a random access event that triggers the sending of a random access message; a user service currently being used by the user equipment, optionally the user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and contractual terms, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and It can be implemented with several different criteria, including subcarrier spacing, which defines the frequency distance between two consecutive subcarriers, or any combination thereof.

[0129] Further details regarding the different criteria have already been presented in connection with embodiment 1, and to avoid repetition, the reader is referred to these sections of the description related to embodiment 1. In one example, the MME configures QoS parameters for the UE (e.g., using the NAS Attach Accept message defined in clause 5.5.1.2.2 of 3GPP TS 24.301). Based on the QoS values ​​(i.e., reflecting contractual agreements), the UE calculates back-off values ​​and / or power ramping parameters from a table. For example, a premium user UE uses higher power ramping and lower back-off values ​​compared to a general user UE.

[0130] Correspondingly, different backoff time values ​​may be associated with appropriate prioritization criteria (or combinations thereof) to reflect the respective priorities associated with the backoff time values. A simple example backoff index table is provided below, which differentiates backoff time values ​​based on the received backoff index value (the "index" in the table, which is typically 0-15) and based on the random access event that triggered the random access procedure for which the backoff index is received from the gNB.

[0131] [Table 6]

[0132] One or more composite examples of the backoff index table are shown below.

[0133] [Table 7]

[0134] As is evident from the above table, different user services may thus have different back-off time values ​​for the same RA event (eg, RA events 2 and 3).

[0135] As is evident from the above exemplary backoff time table, in this case the backoff index table allows for the definition of a range of backoff time values ​​(e.g., 0-10 ms for index 0) based on the backoff index received from the gNB, while the UE selects an appropriate backoff time value within the set range (e.g., 4 ms for RA event 2 and eMBB) based on prioritization criteria (e.g., random access event, user service, contractual agreement). Therefore, using the backoff index table, it is possible for the UE to prioritize random access procedures for specific RA events or user services (or a combination thereof), etc.

[0136] As described in a similar manner for the random access configuration information of the first embodiment, the necessary information on the backoff index table can be provided to the UE in different ways. Correspondingly, one possible way is for the necessary information to be defined by the 3GPP technical specifications and thus effectively hard-coded in the UE's operating system. Another possible way is for the gNB to provide the UE with the necessary information on the backoff index table, for example, in system information. As currently tentatively envisioned in 5G, it is possible to provide the system information in a minimum SI, and / or other SI, and / or SI-on-demand message, and / or a designated RRC message directly addressed to the UE(s). As a result, any of these messages, or a combination thereof, can be used to convey the backoff index table information to the UE.

[0137] A simplified exemplary illustration of UE behavior involved in the enhanced random access procedure of this second embodiment and variations thereof, as described herein, is provided in sequence diagram form in Figure 12. Further, a simplified exemplary illustration of gNB behavior involved in the enhanced random access procedure of this embodiment and variations thereof, as described herein, is provided in sequence diagram form in Figure 13.

[0138] As is evident from Figure 13, it is assumed that a random access procedure is eventually triggered in the UE, thus triggering the transmission of a first random access message from the UE to the gNB. In contrast to the central concept of embodiment 1 described above, a common PRACH resource is used by the UE to transmit the triggered random access message to the gNB, i.e., using the PRACH resource (i.e., radio resource time and frequency, preamble sequence, transmission power, which is also an option described below, see also Figure 9) without reference to any of the prioritization criteria (RA event, user service, subcarrier spacing, contractual agreement).

[0139] The base station receiving the random access message then determines a backoff index in the usual manner (e.g., see the LTE RACH procedure, as described above) and then conveys the determined backoff index to the UE as a random access response (RAR) message. Based on this received backoff index, the UE can then determine the actual backoff parameter values ​​using the backoff time table described above, which additionally takes into account prioritization criteria (random access event, and / or user service, and / or contractual agreements, and / or subcarrier spacing).

[0140] In a similar or identical manner as for the first embodiment, the UE may simply determine its transmit power when performing the enhanced random access procedure according to this second embodiment without reference to any of the prioritization criteria described above, which is similar to how current LTE RACH procedures work.

[0141] On the other hand, the random access prioritization according to the second embodiment can be further implemented, additionally or independently, by determining in the UE an appropriate transmission power to be used for transmitting the first RA message of the RA procedure. Once the RA transmission parameters have been determined in the UE, the UE needs to determine at what radio power to transmit the RA message. This decision can be made based on any of the above-mentioned prioritization criteria or a combination thereof, in a manner similar to how the UE determines the back-off time value. A corresponding transmission power table can be provided to the UE that associates specific transmission power values ​​with specific prioritization criteria, thus enabling the UE to determine for each triggered random access procedure an appropriate transmission power to be used when transmitting the first RA message of the RA procedure.

[0142] One simple and illustrative example of a transmit power table that implements prioritization based solely on random access events, as described in connection with the first embodiment, is as follows:

[0143] [Table 8]

[0144] Another simple exemplary transmit power table that implements prioritization based solely on user service is as follows:

[0145] [Table 9]

[0146] A more detailed transmit power table distinguishing between some specific combinations of random access events, user services, and contract status is as follows:

[0147] [Table 10]

[0148] As is evident from the above table, different user services (eg URLLC and eMBB) may therefore have different transmit power parameters for the same RA event (eg RA events 2 and 3).

[0149] The necessary information for the transmit power table is made available to the UE. There are several options as to how this can be achieved. As described in a similar manner for the first embodiment, the transmit power table may be defined, for example, in a 3GPP technical specification or transmitted by the gNB to the UE using, for example, system information broadcast in the gNB's radio cell. The transmit power table may be provided either in a minimum SI, and / or other SI, and / or on-demand SI message, and / or in a designated RRC message directly addressed to the UE(s). As a result, any of these messages, or a combination thereof, may be used to convey RA configuration information to the UE.

[0150] Increasing the transmission power for random access message transmissions can also be implemented by a further variant of this second embodiment, as is known from LTE. Specifically, the transmission power is continuously increased with each failed RA message transmission based on a given transmission power step size. In the above case, assuming a random access procedure for RA event 1 as an example, the UE thus starts transmitting the first RA message with a transmission power of -120 dbm, and in case of a random access failure, the UE uses a transmission power of -116 dbm for the second attempt to transmit an RA message, -112 dbm for the third attempt thereafter, etc.

[0151] In the second embodiment, using different transmit powers for RA message transmissions to prioritize the random access procedure is particularly beneficial in view of the fact that no differentiation of PRACH resources is made. Therefore, the probability of collision with other UEs during random access remains high compared to the enhanced random access procedure of the first embodiment, in which different PRACH resources are used for different prioritization criteria. For example, increasing the transmit power for a specific important random access event (e.g., random access event 2 - RRC connection re-establishment) increases the chance that the random access procedure for that important random access event will be successful compared to a random access procedure triggered in another UE by a less important random access event (e.g., random access event 1 - initial access).

[0152] Further Aspects

[0153] According to a first aspect, there is provided a user equipment comprising a processor configured to determine, when triggered by one of a plurality of random access events, random access transmission parameters to be used for transmitting a random access message to a base station controlling a radio cell of a mobile communication system in which the user equipment is located. At least some of the random access transmission parameters are determined based on the random access event that triggered the transmission of the random access message and random access configuration information. The random access configuration information associates each of the plurality of random access events with a set of random access transmission parameters from a plurality of random access transmission parameters usable by the user equipment to transmit the random access message to the base station. A transmitter of the UE transmits the random access message to the base station using the determined random access transmission parameters.

[0154] According to a second aspect provided in addition to the first aspect, the plurality of random access transmission parameters comprises: a random access preamble sequence transmitted together with the random access message; the time and frequency of radio channel resources used by the user equipment when transmitting a random access message to the base station; and • a transmission power value to be used by the user equipment when transmitting a random access message to the base station.

[0155] Additionally or alternatively, some of the random access transmission parameters may be: a random access event that triggers the sending of a random access message; a user service currently being used by the user equipment, optionally the user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and contractual terms, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and • Subcarrier spacing, which defines the frequency distance between two consecutive subcarriers; and • associated with one or a combination of two or more of the following.

[0156] According to a third aspect provided in addition to the first or second aspect, some of the random access transmission parameters are associated with a combination of one or more of the random access events and one or more of the user services. Additionally or alternatively, another part of the random access transmission parameters is associated with a combination of one or more of the random access events and a contractual agreement. Additionally or alternatively, the association between the random access transmission parameters and multiple random access events is such that each random access event is associated with a different random access transmission parameter.

[0157] According to a fourth aspect, provided in addition to any of the first to third aspects, a receiver of a UE receives from a base station random access configuration information in system information broadcasted by the base station in a radio cell. Alternatively, the receiver receives from the base station a part of the random access configuration information in minimum system information broadcasted by the base station in the radio cell, receives another part of the random access configuration information in a designated message transmitted by the base station and addressed to the user equipment, or receives another part of the random access configuration information in further system information, which is transmitted by the base station in the radio cell upon request. As a further option, the part of the random access configuration includes information on an association of one or more significant random access events with respective sets of random access transmission parameters.

[0158] According to a fifth aspect provided in addition to any of the first to fourth aspects, a processor determines a transmission power value based on a random access event that triggered transmission and random access configuration information, and a transmitter transmits a random access message based on the determined transmission power value.

[0159] According to a sixth aspect, provided in addition to any of the first to fifth aspects, the receiver receives from the base station, in response to the transmitted random access message, a random access response message including back-off parameters used by the user equipment to determine at least a period of time the user equipment needs to wait before initiating another random access channel procedure. According to one option, the back-off parameters are determined by the base station for the user equipment based on the random access message transmitted by the user equipment to the base station and based on random access configuration information.

[0160] According to a seventh aspect provided in addition to any of the first to sixth aspects, a processor determines, based on the random access configuration information, random access transmission parameters associated with subcarrier spacing to be used by a base station to transmit a random access response message to a user equipment. A transmitter transmits the random access message to the base station using the determined random access transmission parameters. A receiver monitors radio resources for incoming data transmission and the random access response message based on the subcarrier spacing on which the processor determined the random access transmission parameters. The receiver receives the random access response message from the base station based on the subcarrier spacing on which the processor determined the random access transmission parameters.

[0161] According to an eighth aspect, which is provided in addition to any of the first to seventh aspects, an association between a random access transmission parameter and a plurality of random access events is provided, wherein some but not all of the plurality of random access events are associated with different random access transmission parameters, and the remaining random access events are associated with a common random access transmission parameter. A processor determines the common random access transmission parameter when triggered by one of the remaining random access events. A transmitter transmits a second random access message to a base station using the determined common random access transmission parameter. A receiver receives a second random access response message from the base station in response to the transmitted second random access message, the second random access response message including a back-off index. The processor determines a back-off time value indicating at least a period of time that the user equipment needs to wait before initiating another random access channel procedure based on the received back-off index and a back-off index table, the back-off index table associating different back-off time values ​​with the back-off index and the remaining random access events that may trigger transmission of the random access message.

[0162] According to a ninth aspect provided in addition to the eighth aspect, the plurality of random access events include: ●Initial access from RRC_IDLE and ●Connection re-establishment procedure, ●Handover and - Downlink data arrival requiring the user equipment to perform a random access channel procedure; uplink data arrival requiring the user equipment to perform a random access channel procedure; ●State transition from inactive to connected state, • Recovery from beam failure.

[0163] Additionally or alternatively, the random access message is transmitted as the first message of a random access channel (RACH) procedure performed by the user equipment to the base station. In one option, the RACH procedure consists of four steps, and the user equipment's packet duplication status is transmitted together with any signaling message of the RACH procedure. In another option, the RACH procedure consists of two steps, and the user equipment's packet duplication status is transmitted together with the RACH preamble and handover complete messages of the RACH procedure.

[0164] According to a tenth aspect, there is provided a base station including a receiver for receiving a random access message from a user equipment located in a radio cell of a mobile communication system controlled by the base station. The random access message is transmitted by the user equipment when triggered by one of a plurality of random access events. A processor of the base station determines random access transmission parameters to be used by the user equipment to transmit the random access message and determines back-off parameters to be used by the user equipment to determine at least a period of time the user equipment needs to wait before initiating another random access channel procedure. A transmitter of the base station transmits a random access response message to the user equipment, the random access response message including the determined back-off parameters, in response to the transmitted random access message.

[0165] According to an eleventh aspect provided in addition to the tenth aspect, a transmitter broadcasts random access configuration information within a radio cell of the transmitter, the random access configuration information associating each of a plurality of random access events with a set of random access transmission parameters among a plurality of random access transmission parameters usable by user equipment to transmit a random access message to a base station.

[0166] According to a twelfth aspect, there is provided a user equipment comprising: a transmitter configured to transmit a random access message to a base station controlling a radio cell of a mobile communication system in which the user equipment is located when triggered by one of a plurality of random access events. A receiver of the user equipment receives a random access response message from the base station in response to the transmitted random access message, the random access response message including a back-off index. A processor of the UE determines a back-off time value indicating at least a period of time the user equipment must wait before initiating another random access channel procedure based on the received back-off index and a back-off index table, the back-off index table associating different back-off time values ​​with the back-off index and at least one or more of a plurality of random access events that may trigger transmission of the random access message.

[0167] According to a thirteenth aspect provided in addition to the twelfth aspect, a backoff index table is provided for storing different backoff time values ​​as follows: a random access event that triggers the sending of a random access message; a user service currently being used by the user equipment, optionally the user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and contractual terms, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and • Subcarrier spacing, which defines the frequency distance between two consecutive subcarriers, and associated with one or a combination of two or more of the following:

[0168] In one option, the receiver receives the backoff index table in system information broadcast by a base station in the radio cell, or the backoff index table is pre-stored in the operating system of the user equipment.

[0169] According to a fourteenth aspect provided in addition to the twelfth and thirteenth aspects, the processor determines, for transmission of the random access message, a random access transmission parameter among a plurality of random access transmission parameters without reference to a random access event that triggered transmission of the random access message. In one option, the plurality of random access transmission parameters include: a random access preamble sequence transmitted together with the random access message; the time and frequency of radio channel resources used by the user equipment when transmitting a random access message to the base station; and a transmission power value to be used by the user equipment when transmitting a random access message to the base station.

[0170] According to a 15th aspect provided in addition to the 12th to 14th aspects, a processor determines a transmission power value for transmitting a random access message based on a transmission power index table. The transmission power index table stores each transmission power value as follows: a random access event that triggers the sending of a random access message; a user service currently being used by the user equipment, optionally the user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and contractual terms, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and • Subcarrier spacing, which defines the frequency distance between two consecutive subcarriers, and associated with one or more combinations of:

[0171] Hardware and Software Implementations of the Present Disclosure

[0172] The present disclosure can be implemented by software, hardware, or software cooperating with hardware. Each functional block used in the description of each embodiment above can be partially or entirely implemented by an LSI such as an integrated circuit, and each process described in each embodiment can be partially or entirely controlled by the LSI or a combination of LSIs. An LSI can be individually formed as a chip, or a single chip can be formed to include some or all of the functional blocks. An LSI can include data inputs and data outputs coupled to the LSI. Depending on the level of integration, an LSI can also be referred to as an IC (integrated circuit), a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing an integrated circuit is not limited to LSI, and can be implemented using dedicated circuits, general-purpose processors, or special-purpose processors. Additionally, an FPGA (field programmable gate array), which can be programmed after LSI fabrication, or a reconfigurable processor, which can reconfigure the connections and settings of circuit cells arranged within the LSI, can also be used. The present disclosure can be implemented as digital processing or analog processing. If future integrated circuit technology replaces LSI as a result of advances in semiconductor technology or other derivative technologies, the future integrated circuit technology can be used to integrate functional blocks. Biotechnology can also be applied.

[0173] Furthermore, the various embodiments may be implemented by means of software modules, which are executed by a processor or directly in hardware. A combination of software modules and hardware implementation is also conceivable. The software modules may be stored on any kind of computer-readable storage medium, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc. Furthermore, it should be noted that individual features of different embodiments may also be the subject of other embodiments, individually or in any combination.

[0174] Those skilled in the art will recognize that various changes and / or modifications may be made to the present disclosure set forth in the specific embodiments, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

1. A communication device, a processor that, in operation, when triggered by a random access event, determines random access transmission parameters based on the random access event and random access configuration information; a transmitter that, during operation, transmits a random access message to a base station using the random access transmission parameters; Equipped with a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; Communication equipment.

2. The random access transmission parameters are: a random access preamble sequence transmitted together with said random access message; a transmission power value used by the communication device when transmitting the random access message to the base station; and physical random access channel resources used by the communication device when transmitting the random access message to the base station; including at least one of The communication device according to claim 1 .

3. If the random access event is a recovery from a beam failure, using specific physical random access channel resources; If the random access event is an initial access from RRC_IDLE, then use common physical random access channel resources. The communication device according to claim 2 .

4. The random access transmission parameters are: a random access event that triggers said sending of a random access message; a user service currently being used by said communication device, said user service being one of massive machine type communications mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communications URLLC; and - contractual terms, such as respective quality of service requirements to be met, under which the communication device is operated by a user; and a subcarrier spacing that defines the frequency distance between two consecutive subcarriers; and The communication device according to claim 1 .

5. a receiver, in operation, receiving from the base station, in response to the transmitted random access message, a random access response message including a back-off parameter used by the communication device to determine at least a period of time that the communication device will wait before initiating another random access channel procedure; the back-off parameters are determined by the base station for the communication device based on the random access message and the random access configuration information sent by the communication device to the base station. The communication device according to claim 1 .

6. When there are a plurality of random access events, some of the random access events are associated with different random access transmission parameters, and the remaining random access events are associated with a common random access transmission parameter; the processor, during operation, when triggered by one of the remaining random access events, determines the common random access transmission parameters; the transmitter, during operation, transmitting a second random access message to the base station using the determined common random access transmission parameters; a receiver, during operation, receiving a second random access response message from the base station in response to the transmitted second random access message, the second random access response message including a backoff index; and wherein the processor, during operation, determines a back-off time value indicating at least a period of time that the communication device will wait before initiating another random access channel procedure based on the received back-off index and a back-off index table, the back-off index table associating different back-off time values ​​with back-off indexes and the remaining random access events that may trigger the transmission of a random access message. The communication device according to claim 1 .

7. 1. A method for controlling operation of a communication device, comprising: The method comprises: determining random access transmission parameters based on the random access event and random access configuration information when triggered by the random access event; transmitting a random access message to a base station using the random access transmission parameters; Including, a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; method.

8. An integrated circuit for controlling processing of a communication device, The process comprises: determining random access transmission parameters based on the random access event and random access configuration information when triggered by the random access event; transmitting a random access message to a base station using the random access transmission parameters; Including, a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; Integrated circuit.

9. A base station, a processor that, during operation, determines random access transmission parameters to be used by the communication device to transmit a random access message; a receiver that, in operation, receives the random access message from the communication device when triggered by a random access event; Equipped with the random access transmission parameters are determined based on the random access event and random access configuration information; a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; Base station.

10. 1. A method for controlling operation of a base station, comprising: The method comprises: determining random access transmission parameters to be used by the communication device to transmit the random access message; during operation, when triggered by a random access event, receiving the random access message from the communication device; Including, the random access transmission parameters are determined based on the random access event and random access configuration information; a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; method.

11. An integrated circuit for controlling processing of a base station, The process comprises: determining random access transmission parameters to be used by the communication device to transmit the random access message; during operation, when triggered by a random access event, receiving the random access message from the communication device; Including, the random access transmission parameters are determined based on the random access event and random access configuration information; a part of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another part of the random access configuration information is conveyed by a minimum system information (SI) message; Integrated circuit.

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