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EP-4079078-B1 - MESSAGE 2 PDSCH REPETITION BASED ON MULTI-SEGMENT RAR WINDOW

EP4079078B1EP 4079078 B1EP4079078 B1EP 4079078B1EP-4079078-B1

Inventors

  • TAHERZADEH BOROUJENI, MAHMOUD
  • LUO, TAO

Dates

Publication Date
20260506
Application Date
20201201

Claims (13)

  1. A method of wireless communication of a device at a user equipment, UE, comprising: transmitting (602), to a base station, a preamble to initiate a random access channel, RACH, procedure; determining (604) that a first random access response, RAR, is received unsuccessfully during a first portion of a RAR window after transmission of the preamble; receiving (606), from the base station, a first plurality of RARs in response to the transmitted preamble, the first plurality of RARs being received in a first plurality of slots during a second portion of the RAR window that is subsequent to the first portion of the RAR window; decoding (610) unsuccessfully the first plurality of RARs; and receiving (606), from the base station, a second plurality of RARs in a second plurality of slots during a third portion of the RAR window subsequent to the second portion of the RAR window, the second plurality of RARs being received based on the first plurality of RARs being unsuccessfully decoded, wherein the second plurality of slots include a greater number of slots than the first plurality of slots.
  2. The method of claim 1, further comprising: combining (608) the received RARs into one RAR; decoding (610) the one RAR; and transmitting (612), to the base station, a radio resource control, RRC, connection request in response to the one RAR.
  3. The method of claim 1, further comprising receiving at least one physical downlink control channel, PDCCH, scheduling a physical downlink shared channel, PDSCH, for receiving the plurality of RARs, preferably wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window, or wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during the first configured segment of the RAR window.
  4. The method of claim 1, further comprising receiving a configuration indicating a hopping pattern for receiving the plurality of RARs, the configuration being received through one of downlink control information, DCI, or system information, the plurality of RARs being received based on the received configuration, or further comprising receiving a configuration indicating whether RAR repetition is configured, the configuration being received through one of a master information block, MIB, or system information, wherein the plurality of RARs are received based on the received configuration, or further comprising receiving a configuration indicating at least one of a partition of the RAR window for RAR repetitions, a segment within the RAR window for the RAR repetitions, or a number of RAR repetitions for each RAR window partition or segment, the configuration being received through one of a master information block, MIB, system information, or a radio resource control, RRC, message, wherein the plurality of RARs are received based on the received configuration.
  5. A user equipment, UE, comprising: means for transmitting, to a base station, a preamble to initiate a random access channel, RACH, procedure; means for determining that a first random access response, RAR, is received unsuccessfully during a first portion of a RAR window after transmission of the preamble; means for receiving, from the base station, a first plurality of RARs in response to the transmitted preamble, the first plurality of RARs being received in a first plurality of slots during a second portion of the RAR window that is subsequent to the first portion of the RAR window; means for decoding unsuccessfully the first plurality of RARs; and means for receiving, from the base station, a second plurality of RARs in a second plurality of slots during a third portion of the RAR window subsequent to the second portion of the RAR window, the second plurality of RARs being received based on the first plurality of RARs being unsuccessfully decoded, wherein the second plurality of slots include a greater number of slots than the first plurality of slots.
  6. The UE of claim 5, further comprising means for performing a method according to any of claims 2 to 4.
  7. A method of wireless communication of a device at a base station, BS, comprising: receiving (702), from a user equipment, UE, a preamble to initiate a random access channel, RACH, procedure; transmitting (704) a first random access response, RAR, to the UE in response to receiving the preamble, the first RAR being transmitted during a first portion of a RAR window; determining (706) that a radio resource control, RRC, connection request is not received in response to the transmitted first RAR; transmitting (708) a first plurality of RARs to the UE in a first plurality of slots during a second portion of the RAR window subsequent to the first portion of the RAR window upon determining that the RRC connection request was not received in response to the transmitted first RAR; determining that a second RRC connection request is not received in response to the transmitted first plurality of RARs; and transmitting a second plurality of RARs to the UE in a second plurality of slots during a third portion of the RAR window subsequent to the second portion of the RAR window upon determining that the second RRC connection request was not received in response to the transmitted first plurality of RARs, wherein the second plurality of slots include a greater number of slots than the first plurality of slots.
  8. The method of claim 7, further comprising: transmitting at least one physical downlink control channel, PDCCH, scheduling physical downlink shared channels, PDSCHs, for transmissions of the first plurality of RARs.
  9. The method of claim 7, wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window, or wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during the first configured segment of the RAR window.
  10. The method of claim 7, further comprising transmitting a configuration indicating a hopping pattern for the transmission of the first plurality of RARs, the configuration being transmitted through one of downlink control information, DCI, or system information, the first plurality of RARs being transmitted based on the transmitted configuration, or further comprising transmitting a configuration indicating whether RAR repetition is configured, the configuration being transmitted through one of a master information block, MIB, or system information, wherein the first plurality of RARs are transmitted based on the transmitted configuration, or further comprising transmitting a configuration indicating at least one of a partition of the RAR window for RAR repetitions, a segment within the RAR window for the RAR repetitions, or a number of RAR repetitions for each RAR window partition or segment, the configuration being transmitted through one of a master information block, MIB, system information, or an RRC message, wherein the first plurality of RARs are transmitted based on the transmitted configuration.
  11. A base station, BS, comprising: means for receiving, from a user equipment, UE, a preamble to initiate a random access channel, RACH, procedure; means for transmitting a first random access response, RAR, to the UE in response to receiving the preamble, the first RAR being transmitted during a first portion of a RAR window; means for determining that a radio resource control, RRC, connection request is not received in response to the transmitted first RAR; means for transmitting a first plurality of RARs to the UE in a first plurality of slots during a second portion of the RAR window subsequent to the first portion of the RAR window upon determining that the RRC connection request was not received in response to the transmitted first RAR; means for determining that a second RRC connection request is not received in response to the transmitted first plurality of RARs; and means for transmitting a second plurality of RARs to the UE in a second plurality of slots during a third portion of the RAR window subsequent to the second portion of the RAR window upon determining that the second RRC connection request was not received in response to the transmitted first plurality of RARs, wherein the second plurality of slots include a greater number of slots than the first plurality of slots.
  12. The BS of claim 11, further comprising means for performing a method according to any of claims 8 to 10.
  13. A computer-program comprising instructions for performing a method according to any of the claims 1 to 4 when executed by a processor of a UE, or for performing a method according to any of the claims 7 to 10 when executed by a processor of a BS.

Description

BACKGROUND Technical Field The present disclosure generally relates to communication systems, and more particularly, to a message 2 (msg2) random access channel (RACH) response (RAR) physical downlink shared channel (PDSCH) repetition based on a multi-segment RAR window. Introduction Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems. These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra -reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. WO 2017/184460 relates to improvements in random access procedures within a wire-less communication network. To increase the likelihood that a user equipment (UE) will properly decode a random access response message from a base station, the base station may retransmit the random access response message one or more times. The number of retransmissions may be fixed or may be variable depending on whether the base station is able to receive or successfully decode a subsequently transmitted uplink message. US 2017/0280483 A1 provides a method for configuring a Random Access Response (RAR), a base station and a User Equipment (UE). The base station comprises a Medium Access Control (MAC) Protocol Data Unit (PDU) generation unit and a transmission unit. The MAC PDU generation unit is configured to generate a MAC PDU consisting of a MAC header and zero or more MAC Random Access Responses (RARs) corresponding to one or more Physical Random Access Channel (PRACH) resource sets. The PRACH resource sets corresponding to the MAC RARs are distinguish-able based on PRACH Resource Set Indices (PRIs) in the MAC PDU. The transmission unit is configured to transmit the generated MAC PDU on a Physical Downlink Shared Channel (PDSCH). The base station can further comprise a configuration unit configured to configure, via Radio Resource Control (RRC) signaling, MAC signaling or Physical Broadcast Channel (PBCH), or by means of pre-configuration, re-source allocation and other control information for the PDSCH carrying the MAC PDU and/or resource information for RAR M-PDCCH. WO 2016/025899 A1 relates to supporting random access and paging procedures for reduced capability WTRUs in an LTE system. US 10,271,355 B2 provides methods, nodes, a system, and computer storage mediums for non-contention random access. The method for non-contention random access includes that: a first node sends configuration information of non-contention random access to a second node through a downlink channel; and the second node obtains the configuration information of the non-contention random access, and sends a random access message on a Physical Random Access Channel (PRACH) according to the configuration information. US 9,730,249 B2 discloses methods, apparatuses, and systems for establishing lightweight communications between different network components. A messaging process is utilized which includes a random access procedure for a user equipment (UE) and an eNodeB, and a messaging sequence comprising a reduced number of messages (compared to a legacy Radio Resource Control (RRC) Connection messaging sequence) exchanged between different nodes of the network to establish a lightweight connection. These messages can be generated using any combination of pre-configured or pre-determined data specific to either the UE or to lightweight communications. SUMMARY The following presents a simplified summary of one or more aspects in order to p