Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/08—Non-scheduled access, e.g. ALOHA
  • H04W74/0833—Random access procedures, e.g. with 4-step access
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/08—Arrangements for detecting or preventing errors in the information received by repeating transmission, e.g. Verdan system
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1829—Arrangements specially adapted for the receiver end
  • H04L1/1864—ARQ related signaling
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1867—Arrangements specially adapted for the transmitter end
  • H04L1/189—Transmission or retransmission of more than one copy of a message
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
  • H04W72/044—Wireless resource allocation based on the type of the allocated resource
  • H04W72/0446—Resources in time domain, e.g. slots or frames
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
  • H04W72/044—Wireless resource allocation based on the type of the allocated resource
  • H04W72/0453—Resources in frequency domain, e.g. a carrier in FDMA
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/002—Transmission of channel access control information
  • H04W74/004—Transmission of channel access control information in the uplink, i.e. towards network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/08—Non-scheduled access, e.g. ALOHA
  • H04W74/0833—Random access procedures, e.g. with 4-step access
  • H04W74/0841—Random access procedures, e.g. with 4-step access with collision treatment

Definitions

• Various example embodiments relate to random access procedure of a mobile network.
• Random access procedure is used in mobile networks for initiating data transfer.
• Present disclosure relates to development of random access procedure and more specifically to random access messages with repetitions.
• an apparatus comprising means for performing: obtaining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; using the repetition configuration to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions; and using the selected sequence of ROs for transmission of the first message with repetitions.
• determining and selecting the sequence of ROs is performed by using the repetition configuration to determine the candidate sequences of ROs for transmission of the first message with repetitions; and selecting one of the determined candidate sequences of ROs.
• determining and selecting the sequence of ROs is performed by using the repetition configuration to determine one or more candidates for a first RO of the sequence and selecting one of the candidates as the first RO of the sequence; and iteratively determining one or more subsequent candidates for a subsequent RO of the sequence based on the previously selected RO of the sequence and selecting one of the subsequent candidates as the subsequent RO of the sequence until required number of ROs have been selected.
• the selection is performed in a round robin fashion, when there is more than one RO or sequence of ROs to select from.
• selecting the sequence of ROs is fully performed before the first transmission of the first message with repetition.
• selecting the sequence of ROs is performed concurrently with the transmission of the first message with repetitions, wherein a repetition of the first message is transmitted after selecting the RO over which that repetition is to be transmitted and before selecting the RO for the transmission of the subsequent repetition of the first message, if any.
• ROs of the selected sequence of ROs occupy different time resources.
• the one or more cell-specific indicators are received from a network.
• the apparatus of the first aspect is, or is comprised in user equipment.
• an apparatus comprising means for performing: defining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; and providing the defined one or more cell-specific indicators to user equipment, UE, for UE to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions.
• the apparatus of the second aspect is, or is comprised in a network element.
• the network element may be for example a gNB.
• the network element may be a physical device or a virtualized network function comprising one or more virtual machines (VMs) that are for instance running on a virtualization platform comprising one or more virtualization servers.
• VMs virtual machines
• the repetition configuration groups multiple ROs in different frequency/time instances together to form the one or more candidate sequences of ROs.
• the repetition configuration comprises density parameters for generating one or more random sparse matrices for determining connections from one RO to subsequent ROs of the candidate sequences of ROs.
• the repetition configuration comprises one or more sparse matrices providing information on whether an RO is part of a candidate sequence of ROs or not.
• the repetition configuration comprises one or more combinatorial indicators providing the rank of one or more combinations of ROs out of all the possible combinations of ROs, wherein one combination indicates one candidate sequence of ROs.
• the repetition configuration comprises a first binary sequence indicating the first ROs of the candidate sequences of ROs and a second binary sequence indicating groups of ROs where the remaining ROs of the candidate sequences of ROs are located.
• the repetition configuration comprises N*M bits for each configured candidate sequence of ROs, wherein N is the number of ROs in the candidate sequences of ROs and each group of M bits indicate one RO in each group of consecutive ROs.
• the candidate sequences of ROs have at least one of the following in common: the first RO or the last RO, and the repetition configuration comprises single indication(s) of the common RO(s) and sequence specific indications of other ROs of the candidate sequences of ROs.
• the one or more cell-specific indicators comprise a preamble configuration of more than one preamble for transmission of the first message with repetitions for a UE to select a preamble for transmission of the first message with repetitions.
• the one or more cell-specific indicators comprise a maximum time configuration for a UE to determine maximum time duration for transmission of the first message with repetitions.
• the random access procedure is contention based random access, CBRA.
• the means of the apparatus of the first aspect and/or the second aspect comprises at least one processor; and at least one memory including executable instructions that, when executed by the at least one processor, cause the performance of the apparatus.
• a method comprising: obtaining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; using the repetition configuration to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions; and using the selected sequence of ROs for transmission of the first message with repetitions.
• a method comprising defining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; and providing the defined one or more cell-specific indicators to user equipment, UE, for UE to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions.
• obtaining one or more cell-specific indicators wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; using the repetition configuration to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions; and using the selected sequence of ROs for transmission of the first message with repetitions.
• a sixth example aspect of the present disclosure there is provided computer executable program instructions configured to cause performing at least the following: defining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; and providing the defined one or more cell-specific indicators to user equipment, UE, for UE to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions.
• the computer program of the fifth and/or the sixth example aspect may be stored in a non-transitory computer readable memory medium.
• Any foregoing memory medium may comprise a digital data storage such as a data disc or diskette, optical storage, magnetic storage, holographic storage, opto-magnetic storage, phase-change memory, resistive random access memory, magnetic random access memory, solid-electrolyte memory, ferroelectric random access memory, organic memory or polymer memory.
• the memory medium may be formed into a device without other substantial functions than storing memory or it may be formed as part of a device with other functions, including but not limited to a memory of a computer, a chip set, and a sub assembly of an electronic device.
• an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the processor, cause the apparatus to perform obtaining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; using the repetition configuration to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions; and using the selected sequence of ROs for transmission of the first message with repetitions.
• an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the processor, cause the apparatus to perform: defining one or more cell-specific indicators, wherein the cell-specific indicators comprise configuration for aspects of a random access procedure that comprises transmission of a first message with repetitions, wherein the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of random access channel, RACH, occasions, RO, for transmission of the first message with repetitions; and providing the defined one or more cell-specific indicators to user equipment,
• UE for UE to determine and select a sequence of ROs among the candidate sequences of ROs for transmission of the first message with repetitions.
• Fig. 1 shows a signaling diagram of a 4-step RACH procedure of 5G NR
• Fig. 2 shows an example of time-domain resource determination for RACH occasions
• Fig. 3 shows an example of SSB to RO mapping
• FIG. 4-6 show flow charts of processes of some example embodiments
• Fig. 7 lists implementation alternatives of some example embodiments.
• Fig. 8 is a graph presentation of some examples of RO sequences
• Fig. 9 shows a random sparse matrix of an example embodiment
• FIG. 10A-10B illustrate details of some example embodiments.
• Fig. 11 shows a block diagram of an apparatus of an example embodiment.
• Fig 1 shows a signaling diagram of the 4-step RACH procedure of 5G NR.
• Fig. 1 shows a user equipment (UE) 101 and NR Node B (gNB) 102.
• the messages of the 4- step RACH procedure as shown in Fig. 1 can be summarized as follows:
• First message Msg1 (a.k.a PRACH): The UE 101 sends a specific preamble to the gNB 102 via physical random access channel (PRACH) using a specific resource called RACH occasion (RO).
• Second message Msg2 (a.k.a. RAR): The gNB 102 replies with a random access response (RAR) message, which includes a detected preamble ID, a time-advance command, a Temporary Cell RNTI, Radio Network Temporary Identifier (TC- RNTI), and UL grant for the transmission of a third message Msg3 on physical uplink shared channel (PLISCH).
• RAR random access response
• Third message Msg3 (a.k.a. RRC request): The UE 101 responds to Msg2 over the scheduled PLISCH with an ID for contention resolution.
• Fourth message Msg4 (a.k.a. RRC setup): The gNB 102 transmits the contention resolution message with the contention-resolution ID.
• the UE 101 Upon reception of Msg4, the UE 101 sends an ACK on a PUCCH if its contention-resolution ID is carried by Msg4. This completes the 4-step RACH. It is worth noting that prior to Msg1 , there is also a preliminary step of sending and receiving the synchronization signal block (SSB), i.e. , DL beam sweeping, which is not formally part of the RACH procedure. As a result of this preliminary step, the UE 101 selects the index of the preferred SSB beam and decodes the associated physical broadcast channel (PBCH) for master information block (MIB), system information block (SIB) and so on. This index is also used by UE to identify a suitable RO for the preamble transmission (i.e. Msg1) according to the SSB-to-RO mapping implicitly conveyed by the SIB1.
• PBCH physical broadcast channel
• MIB master information block
• SIB system information block
• the 2-step RACH is similar to the 4-step RACH as shown in Fig. 1 , except that Msg1 and Msg3 are combined into a MsgA and sent out without waiting for feedback from the network in between (i.e. Msg2 of Fig. 1). Similarly, the gNB combines Msg2 and Msg4 into a MsgB. Various embodiments of present disclosure may be equally applied to Msg1 of Fig. 1 or to the preamble/Msg1 part of MsgA of the 2-step RACH.
• the time-domain resource for RACH occasions is configured via higher-layer signaling by prach-Configurationlndex (in rach-ConfigGeneric), which acts as an indicator to a row of a table specified in 3GPP specification TS 38.211 V17.3.0 (clause 6.3.3.2).
• prach-Configurationlndex in rach-ConfigGeneric
• the UE determines the preamble format for PRACH to find the ROs in time-domain as specified in 3GPP specifications.
• Fig. 2 shows an example of time-domain resource determination for RACH occasions.
• the prach-Configurationlndex is 251.
• the UE determines the following:
• Preamble format C2 should be used.
• the mapping of SSB indices to the determined ROs is necessary for a UE to understand which ROs are associated to the SSB index selected during the preliminary step before the start of the RACH procedure.
• the different SSB indices are beamformed in different directions in the cell, hence selection of a wrong SSB index may entail failure of the RACH procedure.
• a parameter ssb-perRACH-OccasionAndCB- PreamblesPerSSB is configured in RACH-ConfigCommon. This parameter indicates: (i) the number of SSB indices per RO, and (ii) the number of contention-based preambles per SSB index.
• Fig 3 shows an example of SSB-to-RO mapping.
• Fig. 3 illustrates an example of valid ROs in one frame determined as illustrated in Fig. 2.
• Msg1-FDM two
• ssb-perRACH-OccasionAndCB-PreamblesPerSSB 1/2).
• 4G LTE specifications include a Msg1 repetition feature to ensure Msg1 transmission to achieve improved coverage.
• the inventors of present disclosure have observed that the Msg1 repetition feature of 4G LTE is not straightforwardly applicable to 5G NR as there are differences between LTE and NR systems when it comes to radio air interface.
• 5G NR is based on a beam-based architecture which heavily relies on analog and/or digital beamforming. This was not the case in LTE, where beam management is more rudimentary.
• Msg1 repetitions which may span large time intervals to find out only at the end that a collision occurred at gNB side and Msg1 needs to be re-transmitted.
• This timeline becomes even longer when considering that UL slots may not be always contiguous (e.g. in a TDD system) and that multiple SSB indices (up to 64 in FR2) may be in use at the network. Therefore, collisions in Msg1 repetitions may cause huge delays in initial access and should be avoided particularly in case of low-SNR CE UE at cell-edge performing Msg1 repetitions. Further, assigning completely independent resources (i.e. preambles and ROs) for several UEs performing Msg1 repetitions is not always possible.
• gNB has no constructive means to distinguish two UEs repeating Msg1 even if dedicated resources were configured for the Msg1 repetitions, since such resources could only be cellspecific. This may hinder the realizability of coherent combining of multiple Msgls at gNB, when multiple UEs attempt access with repetitions. This might degrade the performance of Msg1 transmission and reduce the practical usability of Msg1 repetitions.
• the solution is to define in network one or more candidate sequences of ROs for transmission of the Msg1 with repetitions.
• the UE is then allowed to select a sequence of ROs among the candidate sequences.
• a group of back-to-back OFDM symbols are defined as a time instance, i.e., the time duration of one RO in a slot.
• Fig. 4 shows a flow chart of a process of an example embodiment.
• the process may be implemented for example in a UE such as the UE 101 of Fig. 1 or in apparatus [0067]
• Step 401 One or more cell-specific indicators are obtained.
• the cell-specific indicators comprise configuration for aspects of a RACH procedure that comprises transmission of a first message with repetitions.
• the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of ROs for transmission of the first message (Msg1) with repetitions. I.e. the repetition configuration defines one or more candidate sequences of ROs for UEs of the respective cell to choose from.
• the repetition configuration groups multiple ROs in different frequency/time instances together to form the one or more candidate sequences of ROs.
• the groupings may be provided as relationships between configured ROs via higher-layer parameters prach-Configurationlndex and ssb-perRACH-OccasionAndCB- PreamblesPerSSB.
• the candidate sequences of ROs have the following characteristics:
• ROs sharing the same time resources cannot be part of the same sequence.
• ROs in a sequence are ordered according to their index (as per specification), e.g., first in increasing order of frequency resource index, second in increasing order of time resource index and third in increasing order of indices of PRACH slot.
• Sequences may overlap, i.e., the same RO may be part of more than one sequence.
• An RO that is part of more than one candidate sequence corresponds to a node in graph for which multiple incoming and/or outgoing edges exist. This feature provides low collision probability with a minimum number of resources.
• the one or more cell-specific indicators may further comprise a preamble configuration of more than one preamble for transmission of the first message with repetitions.
• the preamble configuration may be used in the UE to select a preamble for transmission of the first message with repetitions.
• the preambles for transmission of the first message with repetitions may be part of a reserved set, i.e., they cannot be selected by UEs not performing transmission of the first message with repetitions.
• the one or more cell-specific indicators may further comprise a maximum time configuration.
• the maximum time configuration may be used in the UE to determine maximum time duration for transmission of the first message with repetitions. Details of implementation examples of the maximum time configuration are discussed later in this disclosure.
• the cell-specific indicators may be provided to the UE from the network (e.g. gNB) e.g. by broadcasting or signaling this information in the respective cell. Such broadcasting or signaling may take place prior to a formal RACH procedure, e.g. in a preliminary step of sending and receiving the synchronization signal block (SSB) etc.
• the repetition configuration may be used by the UE in conjunction with higher-layer parameters prach-Configurationlndex and ssb-perRACH-OccasionAndCB-PreamblesPerSSB defined for RACH procedure.
• Step 402 The repetition configuration is used to determine and select a sequence of ROs for transmission of the first message with repetitions.
• Step 402 may be implemented by first determining all candidate sequences of ROs in accordance with the repetition configuration and then selecting one of the determined candidate sequences.
• an iterative process may be implemented without fully determining all possible candidate sequences.
• one or more candidates for a first RO of the sequence are determined in accordance with the repetition configuration and one of the candidates is selected.
• subsequent ROs are iteratively determined and selected until required number of ROs have been selected so that one or more subsequent candidates for a subsequent RO of the sequence are determined based on the previously selected RO and one of the determined subsequent candidates is selected.
• the selected sequence of ROs is fully determined whilst other candidate sequences are not necessarily determined as they are not necessarily needed at all. Whenever there is more than one RO or sequence of ROs to select from, the selection may be performed in a round robin fashion.
• Step 402 may comprise using the repetition configuration in conjunction with the parameters prach-Configurationlndex and ssb-perRACH-OccasionAndCB- PreamblesPerSSB.
• the ROs of the selected sequence of ROs occupy different time resources.
• Step 403 The selected sequence of ROs is then used for transmission of the first message with repetitions in the RACH procedure.
• Fig. 5 shows a flow chart of a process of an example embodiment. The process may be implemented for example in a network element such as the gNB of Fig. 1 or in apparatus 1100 of Fig. 11. The process comprises the following steps:
• Step 501 One or more cell-specific indicators are defined.
• the cell-specific indicators comprise configuration for aspects of a RACH procedure that comprises transmission of a first message with repetitions. Further, the cell-specific indicators comprise a repetition configuration for determining one or more candidate sequences of ROs for transmission of the first message with repetitions. I.e. defining the one or more cell-specific indicators comprises defining one or more candidate sequences of ROs for UEs of the respective cell to choose from.
• the one or more cell-specific indicators may further comprise a preamble configuration of more than one preamble for transmission of the first message with repetitions for a UE to select a preamble for transmission of the first message with repetitions.
• the one or more cell-specific indicators may further comprise a maximum time configuration for a UE to determine maximum time duration for transmission of the first message with repetitions.
• the maximum time configuration may be expressed as a function of a number of subframes, as a function of a number of system radio frames, as a function of a number of ROs, as a function of a number of OFDM symbols, and/or as a function of the PRACH configuration or association period.
• the repetition configuration is defined in conjunction with parameters prach-Configurationlndex and ssb-perRACH-OccasionAndCB- PreamblesPerSSB defined for RACH procedure.
• the choice would be up to the network, wherein one or several cellspecific parameters may be defined to cover all possible supported numbers of repetitions or to provide higher diversity in the RO selection at the UE.
• Step 502 The defined one or more cell-specific indicators are provided for use in UEs. This may be done by broadcasting the one or more cell-specific indicators in the cell. A UE in the cell may then determine and select a sequence of ROs for transmission of the first message with repetitions for the RACH procedure.
• Fig. 6 shows a flow chart of a process of an example embodiment.
• the process may be implemented for example in a UE such as the UE 101 of Fig. 1 or in apparatus 1100 of Fig. 11.
• the process comprises the following steps:
• Step 601 One or more cell-specific indicators are obtained.
• the cell-specific indicators comprise configuration for aspects of a RACH procedure that comprises transmission of a first message with repetitions. Further, the cell-specific indicators comprise repetition configuration for determining one or more candidate sequences of ROs for transmission of the first message with repetitions.
• the cell-specific indicator(s) may further comprise a preamble configuration and a maximum time configuration as discussed in connection with step 401 of Fig. 4 and step 501 of Fig. 5.
• Step 602 The one or more cell-specific indicators are used for configuring RACH resources for transmission of the first message, Msg1 , with repetitions and the following is determined: candidate sequences of ROs for transmission of Msg1 with N repetitions within the configured maximum time duration, and a preamble for transmission of Msg1 with N repetitions.
• Step 603 It is checked if there are one or more determined candidate sequences.
• Step 604 If it is concluded that there is one determined candidate sequence, the determined candidate sequence is selected, and transmission of Msg1 with N repetitions is performed using N ROs of the selected sequence.
• Step 605 If it is concluded that there are more than one determined candidate sequences, it is checked if all determined candidate sequences share the same first (or last) RO.
• Step 606 If it is concluded that all determined candidate sequences share the same first RO, the first RO common to all determined sequences is selected.
• Step 607 If it is concluded that all determined candidate sequences do not share the same first RO, one of the ROs determined as first RO of a sequence is selected.
• the selection may be performed in a round robin fashion.
• the selection mechanism may be defined in the cell-specific indicators or hard-coded in the specification.
• different UEs can be separated at network e.g. by transmitted preamble.
• Step 608 One of the possible next ROs following the selected first RO is selected.
• the selection may be performed in a round robin fashion.
• the selection mechanism may be defined in the cell-specific indicators or hard-coded in the specification.
• Step 609 It is checked if N ROs have been selected. If it is concluded that N ROs have not been selected yet, the process returns to step 608 to select next RO.
• Step 610 If it is concluded that N ROs have been selected, transmission of Msg1 with N repetitions is performed using sequence of N selected ROs.
• Fig 7 is a graph presentation of some examples of candidate sequences of ROs.
• each sequence of ROs is represented by a set of nodes connected by directed edges.
• the nodes are arranged in a matrix, wherein nodes in the same row share the same frequency resource and nodes in the same column share the same time resource.
• the index of the frequency resource occupied by the nodes increases from bottom-to-top, and the index of the time resource increases from left-to-right.
• the UE receives a cell-specific indicator comprising repetition configuration of the candidate sequences of Fig. 7. Based on the repetition configuration, the UE fully determines the three candidate sequences of ROs 1-3 and then selects one of the determined sequences, e.g. 1. [RO#1 RO#6 RO#11 RO#13],
• the UE receives a cell-specific indicator comprising repetition configuration of the candidate sequences of Fig. 7. Now, the UE does not determine the three sequences entirely, but determines at least one full sequence, which is the one that will be selected eventually, as follows:
• Fig. 8 lists implementation alternatives of some example embodiments. There are listed different alternatives that may be used for conveying the repetition configuration to the UE. Some of the listed alternatives may be combined or used in parallel.
• the repetition configuration comprises density parameters for generating one or more random sparse matrices for determining connections from one RO to subsequent ROs of the candidate sequences of ROs.
• the UE generates, based on the density parameters, one or more random sparse matrices or vectors that provide the connections from one RO to subsequent configured ROs associated with the same SSB index and within the configured maximum time duration for transmission of the first message with repetitions.
• a sparse matrix/vector is a matrix/vector of ones and zeros, with a density of ones (number of ones among the total number of entries) equal to the configured density.
• the sparse matrix/vector shall be randomly generated with a seed that depends at least on the time and frequency resource occupied by the RO(s) under consideration. Additionally, the seed could depend on the SSB index the RO is associated with.
• a set of one or more cell-specific seeds could also be configured by the network in order for the network to control which ROs are part of which sequence to a larger degree.
• Fig. 9 shows a random sparse matrix of an example embodiment.
• the shown matrix is of size 16x16, with configured density equal to 6% (yielding 14 ones over 16x16 entries) related to 16 configured ROs (that may or may not be arranged in time and frequency as in Fig. 7) that may be part of a sequence of ROs, as per Fig. 7 (in which connected nodes are part of the same sequence).
• bit corresponding to row 6 and column 11 is set to 1 , representing a present connection between RO#11 and RO#6. Same rationale applies to the other ROs. Symmetrically, the bit corresponding to row 11 and column 6 is also set to 1. For this reason, the determination of ROs in each sequence does not require the indication of the entire matrix, but only of the part below or above its main diagonal 910.
• sparse vectors can be generated, one per each RO in each sequence, to represent the next RO(s) in the one or more sequences including the considered RO, located in the next time instance.
• the number of next ROs in the next time instance is equal to the minimum number of sequences including the considered RO.
• four (4) possible candidate next ROs in the sequence exist for each RO in a given time instance, and thus a random sparse vector of length 4 and configured density needs to be created per each RO in a sequence of ROs.
• Fig. 7 four (4) possible candidate next ROs in the sequence exist for each RO in a given time instance, and thus a random sparse vector of length 4 and configured density needs to be created per each RO in a sequence of ROs.
• RO#1 is configured with a density of 0.5 (2 next ROs in the next time instance, i.e., RO#1 is included in at least 2 sequences) whereas, for example, RO#4 is configured with a density of 0.25 (1 next RO in the next time instance, i.e., RO#4 is included in at least one sequence.
• only one density value is configured for generation of the sparse matrix or vectors.
• the density value will be different and require fewer or more bits for lower and larger maximum number of sequences including the considered RO.
• 10 states need to be represented by the density value, which would require a total of 4 bits for configuring it.
• the repetition configuration comprises one or more sparse matrices providing information on whether an RO is part of a candidate sequence of ROs or not.
• the repetition configuration is provided in the form of the sparse matrix or vectors providing information on whether an RO is part of a sequence or not.
• the information is provided, if applicable, for each configured ROs associated to the same SSB index and within the configured maximum time duration for transmission of the first message with repetitions irrespective of whether the RO is actually part of a sequence or not.
• the interpretation of the configuration is the same as in the alternative 801.
• the repetition configuration comprises one or more combinatorial indicators providing the rank of one or more combinations of ROs out of all the possible combinations of ROs of the candidate sequences of ROs, wherein one combination of ROs indicates one candidate sequence of ROs.
• each sequence of N ROs (for transmission of the first message with N repetitions) out of the K consecutive ROs associated with same SSB beam are ordered according to their index (determined as per specification).
• the combinatorial indicator provides the rank of one combination out of all the possible combinations of N ROs out K ROs to transmit the first message with N repetitions.
• One combinatorial indicator indicates one sequence of N ROs in K consecutive ROs using [log 2 ( ⁇ ) bits. If L > 1 sequences are configured by the network, each sequence is indicated independently using the rank of the corresponding combination, and the overall bitwidth of the combinatorial indicator for all sequences is L [log 2 ( ⁇ ) bits.
• the repetition configuration comprises a first binary sequence indicating the first ROs of the candidate sequences of ROs and a second binary sequence indicating groups of ROs where the remaining ROs of the candidate sequences of ROs are located.
• K consecutive ROs associated with same SSB beam are ordered according to their index (determined as per specification), and are grouped in - groups of at most F consecutive ROs.
• F may be the number of ROs in the same time instance, or alternatively a parameter signaled by the network with an additional indicator.
• the network indicates at least one RO in the first group of F consecutive ROs by using a first binary sequence of at least M bits.
• the UE may then determine valid RO sequences by determining the remaining ROs of each sequence of ROs out of the remaining groups of F consecutive ROs.
• the remaining groups of F consecutive ROs can be back-to- back and subsequent to the first group of F consecutive ROs or the network can additionally indicate a second binary sequence of T > N bits for indicating the remaining groups of F consecutive ROs where the remaining ROs are located.
• the latter may require the network to indicate the value of T, unless it is hardcoded in specification.
• FIGs. 10A-10B illustrate details of some example embodiments of the alternative 804.
• next valid ROs in the second group of F consecutive ROs are the ROs associated with the binary sequences 00 and 11 (differ from 10 by only 1 bit).
• the next valid ROs in the third group of F consecutive ROs are the ROs associated with the binary sequences 01 and 10.
• N the maximum number of ROs per sequence
• Each bit in the second binary sequence indicates whether a corresponding group of subsequent F consecutive ROs includes one of the remaining ROs or not. For instance, if such binary sequence is [0 1 1 0 0 1] as shown in Fig. 10 B, the groups of F consecutive ROs including the remaining ROs of the sequences are the 3 rd , 4 th , and 7 th groups of F consecutive ROs (or the 3 rd , 4 th , and 7 th columns as per example in Fig. 10 B). Then the method proceeds as follows. The next valid ROs in the 3 rd group of F consecutive ROs (3 rd column) are the ROs associated with the binary sequences 00 and 11 (differ from 10 by only 1 bit).
• the next valid ROs in the 4 th group of F consecutive ROs (4 th column) are the ROs associated with the binary sequences 01 and 10.
• the same method is applied for each valid RO until reaching the number of ROs per sequence (N).
• ⁇ j -1 bits may be needed for indicating T (if T is not hardcoded in the specification). Therefore, a total bitwidth of [ ⁇ ]+7 10 bits is needed in this example.
• the repetition configuration comprises N*M bits for each configured candidate sequence of ROs, wherein N is the number of ROs in the candidate sequences of ROs and each group of M bits indicate one RO in each group of consecutive ROs.
• [log 2 F] bits would be necessary in case the parameter F needs to be configured and signaled by the network.
• the alternative 805 may be particularly convenient when the number of ROs in the same time instance is larger than 1.
• Alternative 806 The candidate sequences of ROs have the first and/or last RO in common and the repetition configuration comprises single indication(s) of the common RO(s) and sequence specific indications of other ROs of the candidate sequences of ROs.
• Fig. 10 A all the sequences of ROs share the same first RO, associated with the binary sequence 10.
• the network then needs2 bits to indicate the common RO and 6 bits for indicating the remaining ROs for each sequence of ROs. Therefore, the network only needs to indicate the following sequences (the order can differ) [10], [00 01 00], [00 10 00], [00 01 11], [00 10 11], [11 01 00], [11 01 11], [11 10 00] [11 10 11], for indicating the first common RO, and all the remaining ROs of all sequences, yielding 50 bits in total.
• Fig 11 shows a block diagram of an apparatus 1100 according to an example embodiment.
• the apparatus 1100 may operate as a network element, such as the gNB 102 of Fig. 1 , or as a UE, such as the UE 101 of Fig. 1.
• the apparatus 1100 generally comprises a memory 1140 including a computer program code 1150.
• the apparatus 1100 further comprises a processor 1120 for controlling the operation of the apparatus 1100 using the computer program code 1150, and a communication unit 1110 for communicating with other nodes. Further, the apparatus 1100 may comprise a user interface unit 1130.
• the communication unit 1110 comprises, for example, one or more of: a local area network (LAN) port; a wireless local area network (WLAN) unit; Bluetooth unit; cellular data communication unit; or satellite data communication unit.
• the communication interface 1110 may support one or more different communication technologies.
• the communication interface 1110 may support Ethernet communications and/or IP based communications.
• the apparatus 1100 may also or alternatively comprise more than one of the communication interfaces 1110.
• the processor 1120 comprises, for example, any one or more of: a master control unit (MCU); a microprocessor; a digital signal processor (DSP); an application specific integrated circuit (ASIC); a field programmable gate array; and a microcontroller.
• the user interface unit 1130 may comprise a circuitry for receiving input from a user of the apparatus 1100, e.g., via a keyboard; graphical user interface of a display; speech recognition circuitry; or an accessory device; such as a headset; and for providing output to the user via, e.g., a graphical user interface or a loudspeaker.
• Various parts may be implemented using more than one corresponding or different elements, such as memories and storages may be multiplied for capacity and/or redundancy purposes.
• processing and/or communications may be implemented with multiple parallel or elements for capacity and/or redundancy purposes.
• the computer program code 1150 may control the apparatus 1100 to implement one or more example embodiments of present disclosure, such as the processes of Figs. 4-6 and further details discussed in connection with Figs. 7-9, and 10A-10B.
• circuitry may refer to one or more or all of the following:
• circuit(s) and or processor(s) such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.
• software e.g., firmware
• circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware.
• circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
• a technical effect of one or more of the example embodiments disclosed herein is improved random access procedure.
• Another technical effect of one or more of the example embodiments disclosed herein is providing details of random access procedure suited for 5G NR. More specifically, various embodiments provide configuration and determination of the RACH resources for Msg1 repetitions in a manner suited for 5G NR.
• Yet another technical effect of one or more of the example embodiments disclosed herein is that they may reduce the collision probability among UEs in coverage shortage performing Msg1 repetitions. Yet another technical effect of one or more of the example embodiments disclosed herein is that the detection complexity at the receiver (to distinguish between UEs) may be reduced, e.g. in comparison to a system in which UEs can choose ROs randomly with no structured approach to RO determination and selection. Various example embodiments provide that the number of blind decoding instances may be lower than in some other approaches. Yet another technical effect of one or more of the example embodiments disclosed herein is that practical usability of the Msg1 repetition feature may be increased. Yet another technical effect of one or more of the example embodiments disclosed herein is that the amount of resources needed for Msg1 repetitions is not excessively increased.
• Embodiments of the present disclosure may be implemented in software, hardware, application logic or a combination of software, hardware, and application logic.
• the software, application logic and/or hardware may reside e.g. on the gNB 102 or on the UE 101.
• the application logic, software, or an instruction set is maintained on any one of various conventional computer-readable media.
• a “computer-readable medium” may be any non-transitory media or means that can contain, store, communicate, propagate, or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted in Fig. 11 .
• a computer-readable medium may comprise a computer-readable storage medium that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.
• the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the before-described functions may be optional or may be combined.
• UE User Equipment gNB: NR Node B
• Msg1 Message 1 PRACH: Physical Random Access Channel
• RACH Random Access Channel
• SS/PBCH Synchronization Signal/Physical Broadcast Channel
• SSB Synchronization Signal Block
• SIB1 System Information Block 1
• TDD Time Division Duplexing
• FDD Frequency Division Duplexing
• OFDM Orthogonal Frequency Division Multiplexing

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=88506962

Family Applications (1)

Country Status (6)

Families Citing this family (3)

Family Cites Families (1)

• 2023
  • 2023-09-18 KR KR1020257013441A patent/KR20250075668A/ko active Pending
  • 2023-09-18 EP EP23793236.3A patent/EP4591663A1/de active Pending
  • 2023-09-18 WO PCT/EP2023/075568 patent/WO2024061790A1/en not_active Ceased
  • 2023-09-18 CN CN202380067757.XA patent/CN119895995A/zh active Pending
  • 2023-09-18 JP JP2025517369A patent/JP2025531398A/ja active Pending
• 2025
  • 2025-03-10 MX MX2025002853A patent/MX2025002853A/es unknown

Also Published As

Similar Documents

Legal Events