User equipment and base station participating 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] Currently, the 3rd Generation Partnership Project (3GPP) is working on the next release (Release 15) of technical specifications for the next generation of cellular technology, also known as the fifth generation (5G). At the 71st 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) meeting (Gothenburg, 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 work item for Release 15 that will define the first 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 can include indoor hotspots, dense urban, rural, urban macro, high speed, etc., deployment scenarios for URLLC can include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time control of vehicles, wide-area monitoring and control systems for smart grids, and mMTC can include scenarios with 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 entirely new system designs and / or the introduction of 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 further considered. In LTE, CP-based OFDM and DFT-S-OFDM are used as waveforms for downlink and uplink transmission, respectively. One of the design goals in NR is to have as common waveforms as possible for the downlink, uplink, and sidelink.

[0006] In addition to waveforms, some basic frame structure(s) and channel coding scheme(s) will be developed to achieve the above objectives. The 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, technical features that are necessary 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] As 3GPP's standardization of NR for the 5G system is in its infancy, some issues remain unclear. For example, there have been discussions about supporting a prioritization mechanism for the random access procedure performed between user equipment and base station. 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 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, during 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 portion of the random access configuration information is conveyed by a designated radio resource control (RRC) message, and another portion 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 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 when triggered by one of a plurality of random access events; 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 in a plurality of random access transmission parameters usable by the user equipment to transmit the random access message to the base station; and 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 a receiver, a processor, and a 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 used by the user equipment to transmit the random access message, and determines back-off parameters used by the user equipment to determine a period of time the user equipment needs to wait before initiating another random access channel procedure; the transmitter transmits a random access response message including the determined back-off parameters to the user equipment in response to the transmitted random access message.

[0013] In one general second aspect, the techniques disclosed herein feature a user equipment including a transmitter, a receiver, and a processor: the transmitter 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 when triggered by one of a plurality of random access events; the receiver 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; the processor determines a back-off time value indicating at least a period of time that the user equipment should 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.

[0014] It is noted that the schematic 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 those benefits and / or advantages may be obtained individually through the various embodiments and features of this specification and drawings, it is not necessary for all of them to be provided in order to obtain one or more of such benefits and / or advantages.

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

[0017] [Figure 1] 1 illustrates an example architecture of a 3GPP NR system. [Diagram 2] 1 illustrates an example user and control plane architecture for LTE, an eNB, and a UE. [Diagram 3] Different subcarrier spacings of 15 kHz, 30 kHz, and 60 kHz and the resulting symbol durations are illustrated. [Figure 4] 1 illustrates an example of system information acquisition message exchange currently being discussed for 5g NR. [Diagram 5] 4 illustrates an example of a message exchange between an eNB and a UE when performing a contention-based RACH procedure. [Figure 6] 4 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 in which 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. 11 is a sequence diagram of the behavior of a UE according to a modified example of the first embodiment. [Figure 11] FIG. 11 is a sequence diagram of the behavior of a base station according to a modified example of the first embodiment. [Figure 12] FIG. 11 is a sequence diagram of the behavior of a UE according to a modified example of the second embodiment. [Figure 13] FIG. 11 is a sequence diagram of the behavior of a base station according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 the fifth generation of cellular technology, simply referred to as 5G, which includes the development of a new radio access technology (NR) that will operate at frequencies up to 100 GHz. 3GPP needs to identify and develop the necessary technology elements to successfully standardize an NR system that meets both immediate market demands and longer-term requirements in a timely manner. To achieve this, the evolution of the air interface as well as the radio network architecture 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, which is incorporated herein by reference in its entirety.

[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 providing the NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination towards the UEs. The gNBs are interconnected among themselves by an Xn interface. The gNBs are also connected to the NGC (Next Generation Core) by a Next Generation (NG) interface, more specifically to the AMF (Access and Mobility Management Function) by an NG-C interface and to the UPF (User Plane Function) by an 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; section 5.4 illustrates a centralized deployment) is presented therein, in which base stations supporting 5G NR can be deployed. Figure 2 illustrates an exemplary decentralized deployment scenario, based on Figure 5.2.-1 of TR 38.301 above, but additionally illustrating an LTE eNB and user equipment (UE) connected to both a gNB and an LTE eNB (which is understood as an eNB according to previous 3GPP standard releases such as LTE and LTE-A). As mentioned above, 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 the layer 2 functions is given in sub-clause 6 of TS 38.300. The functionality of the PDCP, RLC and MAC sublayers is listed in sub-clause 6.4, 6.3 and 6.2 of TS 38.300. The functionality of the RRC layer is 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, which is currently typically assumed for 5G systems, may be based on the user plane structure currently used for 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), with diverse requirements in terms of data rates, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps for downlink and 10 Gbps for uplink) and a user-perceived data rate that is approximately three times the speed 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 ), wide 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) that is appropriate for one use case may not work well for another use case. For example, low latency applications may require a shorter symbol period (hence a larger subcarrier spacing) and / or a smaller number of symbols per scheduling interval (also called TTI) compared to mMTC services. Furthermore, deployment scenarios with large channel delay spreads require a longer CP period compared to 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 value of subcarrier spacing is derived from a specific value of subcarrier spacing multiplied by N, where N is an integer. At the RAN1 meeting RAN1#85 (May 2016, Nanjing), it was concluded as a practical assumption that LTE-based numerology with 15 kHz subcarrier spacing is the baseline design for NR numerology. For the scaling factor N, the baseline design assumption for NR numerology is N=2 n It was concluded that the lower choice of numerology candidates may be made at a future meeting. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, ... are currently under consideration. Figure 3 exemplarily shows three different subcarrier spacings (15 kHz, 30 kHz, and 60 kHz) and the corresponding symbol durations. The 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 further parameters, e.g. SIB1 contains parameters required to determine if a cell is suitable for cell selection as well as information about the time domain scheduling of the other SIBs, e.g. 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 a system information message (SI message), and there are several SI messages, where a 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, e.g., 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] It is currently assumed (though not yet finalized) that in 5G NR, system information is generally split 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 (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 periodically broadcast or provided on request, e.g., appropriate scheduling information for the above. Scheduling information may include, e.g., SIB type, validity information, SI periodicity, and SI window information, as appropriate. Correspondingly, other system information will encompass anything 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 other SI, the UE needs to know whether other SI is available in the cell and whether other SI is broadcasted. For a UE in RRC_CONNECTED state, designated RRC signaling can be used, for example, for requesting and delivering other SI.

[0037] In legacy LTE, the UE is required to (re)acquire system information whenever a cell change occurs, and the UE is also required to reacquire all system information when the system information is changed (e.g., indicated by paging or an incremented, i.e., changed, value tag). For the new system of 5G NR, 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 with the minimum system information. It is assumed that 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 between 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 RACH (Random Access Channel) 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. A mobile terminal in LTE can only be scheduled for uplink transmission if the mobile terminal's uplink transmission is time synchronized. Thus, the random access channel (RACH) procedure plays an important role as an interface between an unsynchronized mobile terminal (UE) and an orthogonal transmission of uplink radio access. 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 RRC_CONNECTED state, a handover from the user equipment's current serving cell to a new target cell performs a random access procedure to achieve uplink time synchronization at the target cell.

[0042] In LTE, two types of random access procedures are provided, allowing access either on a contention-based basis, i.e. with an inherent collision risk, or without contention (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 LTE contention-based random access procedure is described in more detail with reference to Fig. 5. The procedure consists of four "steps". First, the 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 called 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 an allocation of a Temporary Cell Radio Network Temporary Identifier (T-CRNTI) that is used by the eNodeB to address the mobile terminal(s) for which the RACH preamble was detected until the RACH procedure is finished, 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 the temporary C-RNTI.

[0046] Figure 6 shows a contention-free random access procedure of 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, so that there is no risk of collision, i.e., multiple user equipments do not transmit the same preamble. In response, the user equipment then sends the preamble signaled by the eNodeB in the uplink on the PRACH resource. Since the contention-free random access avoids the case where multiple UEs send the same preamble, essentially the contention-free random access procedure is terminated after the random access response is successfully received by the UE.

[0047] Therefore, a similar or the same RACH procedure as just described in relation to Figures 5 and 6 can be adopted in the future for the new radio technology of 5G. However, 3GPP is also considering a two-step RACH procedure for 5G NR, where message 1, which corresponds to messages 1 and 3 of the four-step RACH procedure, is transmitted first. The gNB would then respond with message 2, which corresponds 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 of the messages are optionally configured by the network.

[0048] Furthermore, 3GPP generally agrees that NR communications should support random access prioritization, but does not agree on the details of how this can be achieved in detail, which may involve the possibility of distinguishing between different back-off parameters and power ramping values.

[0049] In contrast, in an LTE system, the UE basically performs the same random access procedure with 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 the 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 needed 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 particular RA event to a UE has higher priority than other access requests. For example, an RA event triggered by an RRC connection re-establishment shall be treated 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 may require faster access and a higher success rate (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 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 event 7 (beam recovery) is currently under discussion for new introduction in 5G NR systems.

[0055] Although random access prioritization has been generally agreed upon by 3GPP, no detailed solutions are 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 insights 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] Moreover, the terms such as procedures, entities, layers, layers, etc. used below are closely related to the terminology used in the LTE / LTE-A system, or in the current discussion items of 3GPP 5G, even though the specific terminology used in relation to the new radio access technology of the upcoming 3GPP 5G communication system has not yet been fully determined. Therefore, the terminology may change in 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 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)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 of the same or another node or network. A node may have one or more interfaces that attach this node to a communication facility or medium through which the node may communicate. Similarly, a network entity may have logical interfaces that attach a functional entity to a communication facility or medium through which the network entity may communicate with other functional entities or corresponding nodes.

[0061] The term "base station" or "radio base station" refers herein 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 given set of functions to other functional entities of the same or another node or network. A physical entity performs several control tasks for a communication device, including one or more scheduling and configuration. It should be noted that the functionality of a base station and the functionality of a communication device may also be integrated in 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 the eNB / gNB communicate with each other over (wireless) physical channels 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 parts, such as one or more processors or some 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 the transmitter, and exchange receive / transmit data. The transceiver may include an RF (radio frequency) front, 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 to 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 the process of transmission and other processes related thereto. The receiver may be responsible for performing the process of reception and other processes related thereto.

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

[0065] In the following, a simple exemplary scenario is assumed: A UE is assumed to be located in the coverage area of ​​radio cell 1 controlled by gNB1, as illustrated in Fig. 8. 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 procedure known from LTE and currently being discussed for 5G NR are provided in the previous section, 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 required.

[0069] In this respect, the prioritization of random access procedures may be adapted such that the back-off time values ​​and / or transmission power values ​​used by the UE for the random access procedures better reflect (and thus facilitate meeting certain requirements), for example imposed by the UE or by the random access event triggering the random access. The back-off parameters are used to determine how long the UE has 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 back-off parameters are provided to the UE by the gNB, for example, in case of collision detection at the gNB, i.e., when several UEs transmit the same preamble to the gNB using the same PRACH resource. The back-off 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 case of a colliding RACH procedure between several UEs.

[0070] As a result, prioritization of random access procedures is particularly useful in cases where collisions occur between different UEs using the same random access resource. The gNB may prioritize further execution of the random access procedures of different UEs by selecting and allocating appropriate backoffs to the different UEs in those cases where the gNB identifies that collisions between random access procedures are performed by 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 a particular PRACH resource (also referred to as random access transmission parameters) with a specific prioritization criterion (e.g. the circumstances according to which the random access should be prioritized).

[0072] For example, the random access transmission parameters are A random access preamble sequence transmitted together with the random access message; and The time and frequency of radio channel resources used by the UE when transmitting a random access message to the gNB; and a transmission 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 presented in Figure 9. As is evident from Figure 9, illustratively, the PRACH resources shall be distinguishable (three dimensions in the diagram of Figure 9) 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 reader should realize that the illustration and distinguishing parameters are merely examples, and that smaller or larger levels are equally possible with respect to time, frequency, and sequence.

[0074] Although the transmission power is in the parameters of the RA message transmission, the gNB may not reliably distinguish one PRACH resource from another. As mentioned above, the transmission 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 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, it is possible to reserve certain preamble sequences for certain prioritization criteria (or combinations thereof), and several preamble sequences can be grouped together and associated with prioritization criteria (or combinations thereof).

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

[0078] Although the above example differentiates PRACH resources based on only one of the dimensions, it is equally possible that different combinations of dimensions are appropriately defined to differentiate PRACH resources. This is particularly beneficial in those cases with fine differentiation of prioritization criteria. In that case, it is possible for the differentiation of PRACH resources to use multiple dimensions to allow many different prioritizations. For example, a particular group of preamble sequences in a particular 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 division is that the set of PRACH resources reserved for a particular random access event (event 2, RRC connection re-establishment), for example, is further divided based on user services (e.g., distinguishing between all or only one or two of the three currently defined user services). As a result, each subset of PRACH resources thus defined is associated with a combination of random access event(s) and user service(s).

[0079] Moreover, random access, A random access event that triggers the sending of a random access message; and 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 commitments, 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, or any combination thereof, including subcarrier spacing, which defines the frequency distance between two consecutive subcarriers.

[0080] For example, a random access procedure triggered by a particular random access event can be prioritized higher than a random access procedure 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) back-off parameter and / or a low transmission power. Similarly, RA event 2 (RRC connection re-establishment) can also be prioritized higher than RA event 1. For example, all or only some of the RA events can be differentiated between 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 particular user service such as URLLC, random access events 2, 3, 4 have a higher priority, while random access events 4 and 5 have a lower priority. According to another example for a particular user service such as eMBB, random access events 2 and 3 have a higher priority, while random access events 4 and 5 have a 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] Moreover, the prioritization of the random access procedures can be based on the user service, i.e., whether the data communication by the UE is currently performed for URLLC, eMBB, or mMTC. As explained in detail in the previous pages, each user service fits different data transmission scenarios with different requirements, e.g., URLLC requires very small delay, eMBB is not delay critical but requires high peak data rate, etc. Therefore, to facilitate meeting the delay requirements of the URLLC user service provided to the UE, it is possible to prioritize the random access procedures for URLLC over the random access procedures for eMBB or mMTC. For example, all or only some of the user services can be differentiated between each other for RA prioritization.

[0082] A user equipment typically operates under a user contract with a network operator, which contract may affect the general provision of user services to that UE compared to other UEs. For example, a premium user, normally paying a higher amount for a premium user contract, may receive a higher quality of service than a standard user, normally paying a 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 random access procedures for premium UEs may be shorter than for random access procedures for normal UEs, and / or the transmission power used for random access message transmission may be higher. For example, all or only some of the possible contractual provisions may be differentiated between 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 the same as 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, calculates an appropriate back-off value for the UE: for high QoS (premium users), the gNB sets low back-off parameters, whereas for general / standard users, the gNB sets high back-off parameters.

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

[0084] The above list of criteria is not exhaustive and further 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 among 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 a specific user service, 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, the random access prioritization of 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 asynchronous state, respectively) even when referring to the same service, eMBB.

[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 (random access events 2, 3, 4, 5, etc.) with the assumption that in some cases the priorities for the corresponding random access procedures will be similar. By grouping certain prioritization criteria, the number of different sets of PRACH resources required is reduced, since in total only a few 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 more detailed information about the random access procedure and the communicating UEs to the gNB 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 partitioned so that the UE selects a PRACH resource according to the triggered random access procedure and / or the UE, and then the gNB can deduce information from the selected PRACH resource used by the UE to transmit the first RA message. In other words, the UE is adapted to use different PRACH resources (i.e. parameters for the transmission of the first random access message) for the transmission of 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) of 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 at both the UE and the gNB. 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. In this respect, no information needs to be exchanged between the UE and the gNB. However, this does not allow for a large flexibility in how the random access procedures are 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 entails the benefit that the PRACH parameterization (i.e. the differentiation of PRACH resources) can be cell-specific and therefore can vary from cell to cell. Correspondingly, when the UE moves from the original 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 made RRC connection reconfiguration message.

[0091] As currently tentatively envisaged in 5G (see also previous description), the system information can be provided either in minimum SI, and / or other SI, and / or on-demand SI messages, but also in designated RRC messages directly addressed to the UE(s). As a result, any of these messages, or a combination thereof, can be used to convey RA configuration information to the UE. For example, the 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, for example, using 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 (where low latency is required) may 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, it is assumed that the UE and gNB random access configuration information is defined such that for any possible triggered random access procedure the UE can derive which PRACH resource to use and the gNB can conversely derive from the PRACH resource used whether and how to prioritize the random access procedure, whereas in other cases 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 its transmit power when performing the enhanced random access procedure without reference to any of the prioritization criteria mentioned above, which is similar to how the current LTE RACH procedure works.

[0095] On the other hand, the random access prioritization according to the first embodiment is additionally or independently further implemented by determining in the UE an appropriate transmission power to be used for transmitting the first RA message of the RA procedure. Having determined the RA transmission parameters in the UE, the UE needs to determine at what radio power to transmit the RA message. This decision can be made in a similar manner to how the UE determines the PRACH resources (distinguishable by the UE) based on any of the above mentioned prioritization criteria or a combination thereof. A corresponding transmission power table may allow the UE to associate a particular transmission power value with a particular prioritization criterion, 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 services is as follows:

[0099] [Table 2]

[0100] A more detailed transmit power table distinguishing between several 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 transmission 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 back-off index table (see details therein), the transmission power table can be transmitted to the UE by the gNB using system information defined, for example, in the 3GPP technical specifications or, for example, broadcasted in the radio cell of the gNB. The transmission power table can be provided either in a minimum SI, and / or other SI, and / or in an 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, can be used to convey the RA configuration information to the UE.

[0105] An increase in transmission power for random access message transmission can also be implemented by a further variant of this embodiment, as known from LTE. In particular, 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 -120dbm, and in case of random access failure, the UE uses a transmission power of -116dbm for the second attempt of transmitting the RA message, -112dbm for the third attempt thereafter, etc. (assuming a 4db step size).

[0106] A simplified exemplary illustration of UE behavior involved in an improved random access procedure of this embodiment and its variants as described herein is presented in the form of a sequence diagram in FIG. 10. Further, a simplified exemplary illustration of gNB behavior involved in an improved random access procedure of this embodiment and its variants as described herein is presented in the form of a sequence diagram in FIG. 11. For ease of illustration only, it is exemplarily 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 the multiple random access events ultimately triggers the random access procedure at the UE. Based on the previously received RA configuration information and taking into account 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 can correspondingly 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 the 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 back-off parameters based on the random access transmission parameters and provides the selected back-off parameters to the UE using a random access response message. One possibility for transmitting the back-off parameters is to reuse the corresponding back-off parameters defined for the LTE RACH procedure, where the back-off index is coded on 4 bits, which allows 16 different back-off indexes. 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, a completely different backoff time table can be defined for 5G NR and the backoff index can be encoded 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 interval that the gNB should use for the transmission of the random access response message. More specifically, a UE in a connected state normally monitors the PDCCH / PDSCH using a corresponding subcarrier interval (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 in order to receive a random access response message from the gNB. Normally, the random access response message is transmitted by the gNB using a reference numerology and therefore a reference subcarrier interval, independently 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, information about which subcarrier interval is currently used by the UE can be provided to the gNB, 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 the subcarrier spacing, and the UE's use of those specific PRACH resources allows 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 those determined PRACH resources.

[0116] This improved variant of the embodiment may be for an 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 a connected mode in this case and therefore has not yet monitored based on a specific subcarrier spacing of the user service, the need for initial access by the UE is reduced, and in the above 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, each with a subcarrier spacing of 15, 30, or 60 kHz.

[0118] In the same manner as already described for the previous case, the random access configuration information required 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 pages for details).

[0119] According to a further improved variant of the first embodiment, the 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 resource, which is considered as indicating the prioritization criterion on the UE side.

[0120] However, as explained above, the variant of the first embodiment allows for grouping of certain prioritization criteria, such as certain random access events. In the above exemplary cases, it is not possible for the gNB to distinguish the random access event within the group of random access events that actually triggered the random access procedure in the UE based on the PRACH resource used. However, in those cases, prioritization of the random access procedures within the 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] Correspondingly, the UE determines the PRACH resources associated with the group of random access events that includes the random access event that actually triggers the random access procedure. These determined PRACH resources are then used by the UE to transmit the 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 the 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 variant 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 thus 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 a specific prioritization criterion. For example, in a variant of the first embodiment, the prioritization of random access procedures by the gNB shall be performed only for a specific prioritization criterion, such as a specific random access event or user service. For other prioritization criteria, a common PRACH resource is used by the UE that does not encode any further information and therefore does not allow 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 sub-divide 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, whereas random access procedures triggered by other random access events can use a designated PRACH resource, as described in connection with the enhanced random access procedure above. In case common PRACH resources are used by the UEs, as explained above, according to one example prioritization of the random access procedure can be achieved on the UE side, which for example knows the prioritization criteria used (random access event and / or user service) and can therefore select the back-off parameters (and transmission 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 the triggered random access procedures compared to the solution provided in embodiment 1. A similar approach has been described in connection with a specific variant 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 UE uses a common PRACH resource to transmit the first random access message of the random access procedure to the gNB. This approach would in this case be the same 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 would not allow the receiving side to distinguish between, e.g., different random access events (different users could still be distinguished, but would not be identified, based on the preamble sequence transmitted with the random access message).

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

[0128] More specifically, for the second embodiment, a back-off time table (also referred to as a back-off index table) is used in the UE to enable the implementation of random access prioritization, the back-off time table associating different back-off time values ​​with both a back-off 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; and 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 commitments, 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 ...

[0129] Further details regarding the different criteria have already been presented in relation to 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 as 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 back-off time values ​​may be associated with appropriate prioritization criteria (or a combination thereof) to reflect the respective priorities associated with the back-off time values. A simple example of a back-off index table is provided below, which differentiates back-off time values ​​based on the received back-off 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 back-off 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 back-off time table, the back-off index table in this case allows the definition of a range of back-off time values ​​(e.g., 0-10 ms for index 0) based on the back-off index received from the gNB, whereas the UE selects an appropriate back-off time value (e.g., 4 ms for RA event 2 and eMBB) within the set range based on prioritization criteria (e.g., random access event, user service, contractual agreement). Thus, using the back-off index table, it is possible to prioritize random access procedures by the UE for specific RA events or user services (or combinations thereof), etc.

[0136] As described in a similar manner for the random access configuration information of the first embodiment, the necessary information on the back-off 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 back-off index table, for example in the system information. As currently tentatively envisaged in 5G, it is possible for the system information to be provided in the minimum SI, and / or other SI, and / or SI on request messages, and / or in designated RRC messages directly addressed to the UE(s). As a result, any of these messages, or a combination thereof, can be used to convey the back-off 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 its variants 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 its variants as described herein is provided in sequence diagram form in Figure 13.

[0138] As is evident from Fig. 13, it is presumed that a random access procedure is finally 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 idea 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 Fig. 9) without reference to any of the prioritization criteria (RA event, user service, subcarrier spacing, contractual agreements).

[0139] The base station receiving the random access message then determines a back-off index in the normal manner (see, e.g., the LTE RACH procedure, as described above) and then conveys the determined back-off index to the UE as a Random Access Response (RAR) message. Based on this received back-off index, the UE can then determine the actual back-off parameter value using the back-off time table described above, which additionally takes into account prioritization criteria (random access events, and / or user services, and / or contractual commitments, and / or subcarrier spacing).

[0140] In a similar or identical manner as for the first embodiment, the UE may simply determine its transmission power when performing the enhanced random access procedure according to this second embodiment without reference to any of the prioritization criteria mentioned 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. Having determined the RA transmission parameters in the UE, the UE needs to determine at what radio power to transmit the RA message. This decision can be made in a similar manner to how the UE determines the back-off time value, based on any of the above-mentioned prioritization criteria or a combination thereof. A corresponding transmission power table can be provided to the UE that associates a particular transmission power value with a particular prioritization criterion, 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 relation to the first embodiment is as follows:

[0143] [Table 8]

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

[0145] [Table 9]

[0146] A more detailed transmit power table distinguishing between several 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 transmission 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 transmission power table can be transmitted by the gNB to the UE using system information defined, for example, in the 3GPP technical specifications or broadcast, for example, in the radio cell of the gNB. The transmission power table can be provided either in a minimum SI, and / or other SI, and / or in an 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, can be used to convey the RA configuration information to the UE.

[0150] An increase in the transmission power for random access message transmission can also be implemented by a further variant of this second embodiment, as 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 -120dbm, and in case of a random access failure, the UE uses a transmission power of -116dbm for the second attempt of transmitting the RA message, -112dbm for the third attempt thereafter, etc.

[0151] In this embodiment 2, using different transmission powers for RA message transmissions to prioritize random access procedures is particularly beneficial in view of the fact that no PRACH resource differentiation is performed. Therefore, the probability of collision with other UEs during random access remains high compared to the improved random access procedure of embodiment 1, where different PRACH resources are used for different prioritization criteria. For example, increasing the transmission power for a certain 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, a user equipment is provided comprising a processor for determining 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 when triggered by one of a plurality of random access events. 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 on 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 in 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 random access transmission parameters include: A random access preamble sequence transmitted together with the random access message; and the time and frequency of radio channel resources used by the user equipment when transmitting a random access message to the base station; 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 include: A random access event that triggers the sending of a random access message; and 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 commitments, 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 • a combination of one or more of the following:

[0156] According to a third aspect provided in addition to the first or second aspect, a part of the random access transmission parameters is 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 the 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 the UE receives from the base station the random access configuration information in system information broadcasted by the base station in the 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, the further system information being transmitted by the base station in the radio cell upon request. As a further option, the part of the random access configuration comprises information on an association of one or more significant random access events with a respective set of random access transmission parameters.

[0158] According to a fifth aspect provided in addition to any one of the first to fourth aspects, a processor determines a transmission power value based on the random access event that triggered the transmission and the random access configuration information. 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 a back-off parameter 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 parameter is 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 the 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, a random access transmission parameter associated with a subcarrier spacing 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 parameter. A receiver monitors radio resources for an incoming data transmission and the random access response message based on the subcarrier spacing based on which the processor determined the random access transmission parameter. The receiver receives the random access response message from the base station based on the subcarrier spacing based on which the processor determined the random access transmission parameter.

[0161] According to an eighth aspect 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 such that 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. The processor determines the common random access transmission parameter when triggered by one of the remaining random access events. The transmitter transmits a second random access message to the base station using the determined common random access transmission parameter. The 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 should 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, - 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 disturbance.

[0163] Additionally or alternatively, the random access message is sent 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 packet duplication status of the user equipment is sent together with any signaling message of the RACH procedure. In another option, the RACH procedure consists of two steps, and the packet duplication status of the user equipment is sent together with the RACH preamble and handover complete messages of the RACH procedure.

[0164] According to a tenth aspect, a base station is provided, comprising 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 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 including the determined back-off parameters to the user equipment 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 in 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 a user equipment to transmit a random access message to a base station.

[0166] According to a twelfth aspect, a user equipment is provided, comprising a transmitter 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 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 that the user equipment should 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, A random access event that triggers the sending of a random access message; and 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 commitments, such as respective quality of service requirements to be met, under which the user equipment is operated by the user; and • Associated with a subcarrier spacing, which defines the frequency distance between two consecutive subcarriers, and one or a combination of two or more of the following:

[0168] In one option, the receiver receives the back-off index table in system information broadcast by a base station in the radio cell, or the back-off 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 to thirteenth aspects, the processor determines, for a transmission of the random access message, a random access transmission parameter among the plurality of random access transmission parameters without reference to a random access event that triggered the 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; and the time and frequency of radio channel resources used by the user equipment when transmitting a random access message to the base station; 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 fifteenth aspect provided in addition to the twelfth to fourteenth aspects, the processor determines a transmission power value for transmitting the random access message based on a transmission power index table. The transmission power index table includes the following transmission power values: A random access event that triggers the sending of a random access message; and 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 commitments, 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 one or more of the following:

[0171] Hardware and Software Implementations of the 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 described above can be implemented partially or entirely by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled partially or entirely by the LSI or a combination of LSIs. The LSI can be individually formed as a chip, or one chip can be formed to include some or all of the functional blocks. The LSI can include data inputs and data outputs coupled to the LSI. Depending on the degree of integration, the 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 the integrated circuit is not limited to an LSI, and can be implemented by using a dedicated circuit, a general-purpose processor, or a special-purpose processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells arranged inside the LSI can also be used. The present disclosure can be implemented as digital processing or analog processing. If future integrated circuit technologies replace LSI as a result of advances in semiconductor technology or other derived technologies, the future integrated circuit technologies can be used to integrate the functional blocks. Biotechnology can also be applied.

[0173] Furthermore, the various embodiments may be implemented by means of software modules 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 is to be noted that individual features of the different embodiments may be the subject of another embodiment, either individually or in any combination.

[0174] It will be apparent to those skilled in the art 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 of the invention.

Claims

1. A communication device, comprising: a processor that, during 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. Communications equipment.

2. The random access transmission parameters are a random access preamble sequence transmitted together with the 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; At least one of the following is included: The communication device according to claim 1 .

3. using specific physical random access channel resources if the random access event is recovery from a beam failure; 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 triggering said transmission of a random access message; a user service currently being used by said communication device, said user service being one of: massive machine type communication mMTC, enhanced mobile broadband eMBB, and ultra reliable low latency communication URLLC; 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, during 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 transmitted 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; determining, during operation, the common random access transmission parameters when triggered by one of the remaining random access events; 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 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 waits 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 a back-off index 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 operations in 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 a 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, comprising: The process comprises: determining random access transmission parameters based on a 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 circuits.

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 adapted, during operation, to receive 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 steps of: The method comprises: determining random access transmission parameters to be used by the communication device to transmit the random access message; during operation, upon triggering 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 circuits.

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