Patent Description:
The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project ("3GPP"), Positive-Acknowledgment ("ACK"), Binary Phase Shift Keying ("BPSK"), Clear Channel Assessment ("CCA"), Cyclic Prefix ("CP"), Cell Radio Network Temporary Identifier ("C-RNTI"), Channel State Information ("CSI"), Common Search Space ("CSS"), Discrete Fourier Transform Spread ("DFTS"), Downlink Control Information ("DCI"), Downlink ("DL"), Downlink Pilot Time Slot ("DwPTS"), Enhanced Clear Channel Assessment ("eCCA"), Enhanced Mobile Broadband ("eMBB"), Evolved Node B ("eNB"), European Telecommunications Standards Institute ("ETSI"), Frame Based Equipment ("FBE"), Frequency Division Duplex ("FDD"), Frequency Division Multiple Access ("FDMA"), Guard Period ("GP"), Hybrid Automatic Repeat Request ("HARQ"), Identifier ("ID"), Internet-of- Things ("loT"), Licensed Assisted Access ("LAA"), Load Based Equipment ("LBE"), Listen-Before-Talk ("LBT"), Long Term Evolution ("LTE"), Medium Access Control ("MAC"), Multiple Access ("MA"), Modulation Coding Scheme ("MCS"), Machine Type Communication ("MTC"), Multiple Input Multiple Output ("MIMO"), Multi User Shared Access ("MUSA"), Narrowband ("NB"), Negative-Acknowledgment ("NACK") or ("NAK"), Next Generation Node B ("gNB"), New Radio ("NR"), Non-Orthogonal Multiple Access ("NOMA"), Orthogonal Frequency Division Multiplexing ("OFDM"), Primary Cell ("PCell"), Physical Broadcast Channel ("PBCH"), Physical Downlink Control Channel ("PDCCH"), Physical Downlink Shared Channel ("PDSCH"), Pattern Division Multiple Access ("PDMA"), Protocol Data Unit ("PDU"), Physical Hybrid ARQ Indicator Channel ("PHICH"), Physical Layer ("PHY"), Physical Random Access Channel ("PRACH"), Physical Resource Block ("PRB"), Physical Uplink Control Channel ("PUCCH"), Physical Uplink Shared Channel ("PUSCH"), Quality of Service ("QoS"), Quadrature Phase Shift Keying ("QPSK"), Radio Link Failure ("RLF"), Radio Resource Control ("RRC"), Random Access Procedure ("RACH"), Random Access Response ("RAR"), Random Access Radio Network Temporary Identity ("RA-RNTI"), Reference Signal ("RS"), Resource Spread Multiple Access ("RSMA"), Round Trip Time ("RTT"), Receive ("RX"), Sparse Code Multiple Access ("SCMA"), Scheduling Request ("SR"), Single Carrier Frequency Division Multiple Access ("SC-FDMA"), Secondary Cell ("SCell"), Shared Channel ("SCH"), Signal-to-Interference-Plus-Noise Ratio ("SINR"), System Information Block ("SIB"), Timing Advanced Group ("TAG"), Transport Block ("TB"), Transport Block Size ("TBS"), Time-Division Duplex ("TDD"), Time Division Multiplex ("TDM"), Transmission Time Interval ("TTI"), Transmit ("TX"), Uplink Control Information ("UCI"), User Entity/Equipment (Mobile Terminal) ("UE"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), Uplink Pilot Time Slot ("UpPTS"), Ultra-reliability and Low-latency Communications ("URLLC"), and Worldwide Interoperability for Microwave Access ("WiMAX").

In certain wireless communications networks, some system information may be transmitted and/or received more often than is necessary. In certain configurations, to reduce the signaling load for providing system information, a minimum amount of system information may be used. The minimum system information ("SI") may contain basic information for initial access to the cell (e.g., subframe number, list of public land mobile networks ("PLMNs"), cell camping parameters, RACH parameters) that is broadcast periodically in a cell. In some configurations, the other non-minimum SI doesn't necessarily need to be periodically broadcast (e.g., it may be a network decision). In various configurations, the other SI may be provided on-demand to UEs (e.g., a UE may request it). Delivery of other SI may be done in a broadcast or unicast manner. In some configurations, the minimum SI may indicate whether a specific SIB is periodically broadcasted or provided on-demand. To obtain the one or more SIBs which are not periodically broadcasted and are provided on-demand, a UE may initiate an on-demand SI acquisition procedure (e.g., SI request). For an SI used by the UE, the UE may determine whether it is available in the cell and whether it is broadcast or not before it sends a request for it. The scheduling information for other SI may be provided by the minimum SI (e.g., an SIB type, validity information, periodicity, SI-window information, etc.).

In various configurations, a UE may not be aware whether an SI request is correctly detected by a gNB and may unnecessarily monitor during the SI window for the delivery of the requested SI. Accordingly, a UE battery may drain unnecessarily and there may be an increase in latency for the SI provisioning. Document <CIT> discloses a wireless device repeatedly transmitting the random access preamble until a random access response corresponding to the random access preamble is received or a predetermined number of transmissions is reached.

<FIG> depicts an embodiment of a wireless communication system <NUM> for performing an action based on a number of transactions reaching a threshold. In one embodiment, the wireless communication system <NUM> includes remote units <NUM> and network units <NUM>. Even though a specific number of remote units <NUM> and network units <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of remote units <NUM> and network units <NUM> may be included in the wireless communication system <NUM>.

The remote units <NUM> may communicate directly with one or more of the network units <NUM> via UL communication signals.

In certain embodiments, a network unit <NUM> may also be referred to as an access point, an access terminal, a base, a base unit, a base station, a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a device, or by any other terminology used in the art.

In one implementation, the wireless communication system <NUM> is compliant with the NR protocols standardized in 3GPP, wherein the network unit <NUM> transmits using an OFDM modulation scheme on the DL and the remote units <NUM> transmit on the UL using a SC-FDMA scheme or an OFDM scheme. More generally, however, the wireless communication system <NUM> may implement some other open or proprietary communication protocol, for example, WiMAX, among other protocols.

In one embodiment, a network unit <NUM> may determine an action selected from a group including: inhibiting communications with the network unit <NUM>; determining a type of system information being requested by a number of transmissions and inhibiting communications with the network unit <NUM> based on the type of system information; determining whether to inhibit communications with the network unit <NUM> based on a configuration of a remote unit <NUM>; and performing additional transmissions to the network unit <NUM>. In various embodiments, the network unit <NUM> may transmit information corresponding to the selected action. Accordingly, a network unit <NUM> may be used for performing an action based on a number of transactions reaching a threshold.

In another embodiment, a remote unit <NUM> may determine whether a number of transmissions to a network unit <NUM> has reached a predetermined threshold. In certain embodiments, the remote unit <NUM> may, in response to the number of transmissions to the network unit <NUM> reaching the predetermined threshold, perform an action selected from a group including: inhibiting communications with the network unit <NUM>; determining a type of system information being requested by the number of transmissions and inhibiting communications with the network unit <NUM> based on the type of system information; determining whether to inhibit communications with the network unit <NUM> based on a configuration of the remote unit <NUM>; and performing additional transmissions to the network unit <NUM>. Accordingly, a remote unit <NUM> may be used for performing an action based on a number of transactions reaching a threshold.

<FIG> depicts one embodiment of an apparatus <NUM> that may be used for performing an action based on a number of transactions reaching a threshold. The apparatus <NUM> includes one embodiment of the remote unit <NUM>. Furthermore, the remote unit <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM>, and a receiver <NUM>. In some embodiments, the input device <NUM> and the display <NUM> are combined into a single device, such as a touchscreen. In certain embodiments, the remote unit <NUM> may not include any input device <NUM> and/or display <NUM>. In various embodiments, the remote unit <NUM> may include one or more of the processor <NUM>, the memory <NUM>, the transmitter <NUM>, and the receiver <NUM>, and may not include the input device <NUM> and/or the display <NUM>.

In various embodiments, the processor <NUM> determines whether a number of transmissions to a network unit has reached a predetermined threshold; and in response to the number of transmissions to the network unit reaching the predetermined threshold, performs an action selected from a group including: inhibiting communications with the network unit; determining a type of system information being requested by the number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit.

In some embodiments, the memory <NUM> stores data relating to system information.

The transmitter <NUM> is used to provide UL communication signals to the network unit <NUM> and the receiver <NUM> is used to receive DL communication signals from the network unit <NUM>.

<FIG> depicts one embodiment of an apparatus <NUM> that may be used for performing an action based on a number of transactions reaching a threshold. The apparatus <NUM> includes one embodiment of the network unit <NUM>. Furthermore, the network unit <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM>, and a receiver <NUM>. As may be appreciated, the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> may be substantially similar to the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> of the remote unit <NUM>, respectively.

In various embodiments, the processor <NUM> may determine an action selected from a group including: inhibiting communications with a network unit; determining a type of system information being requested by a number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit. In some embodiments, the transmitter <NUM> may transmit information corresponding to the selected action. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the network unit <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>.

<FIG> illustrates one embodiment of communications <NUM> for transmitting and receiving feedback for a system information request. Specifically, communications <NUM> between a UE <NUM> and a gNB <NUM> are illustrated. The communications <NUM> may facilitate the UE <NUM> requesting on-demand SIBs using a RACH message <NUM> based approach.

In certain embodiments, the gNB <NUM> may transmit a periodic broadcast <NUM> to the UE <NUM>. The periodic broadcast <NUM> may include minimum SI used by the UE <NUM> for communication. In various embodiments, the UE <NUM> may transmit a PRACH preamble <NUM> to the gNB <NUM>. In some embodiments, in response to transmitting the PRACH preamble <NUM>, the gNB <NUM> may transmit an UL grant in a random access response <NUM>. After receiving the random access response <NUM>, the UE <NUM> may transmit a system information ("SI") request <NUM> to the gNB <NUM> that indicates on-demand SIBs requested by the UE <NUM>. The system information request <NUM> may be a random access message <NUM>. As may be appreciated, the on-demand SIBs may not be broadcast (e.g., transmitted) unless requested. In response to the system information request <NUM>, the gNB <NUM> may transmit a feedback response <NUM> that indicates that the system information request <NUM> was received by the gNB <NUM>.

In certain embodiments, because message <NUM> is a UL-SCH transmission (e.g., medium access control ("MAC") protocol data unit ("PDU")) more information may be provided by the UE <NUM> within the message <NUM> than in a PRACH preamble. In one embodiment, the UE <NUM> includes a MAC control element ("CE") within the RACH message <NUM> to convey the SI request information. In such an embodiment, the MAC CE may contain a bitmap indicating the SI(s)/SIB(s) that the UE <NUM> wants to acquire. Moreover, the bitmap may have an entry for all on-demand SI(s)/SIB(s) (e.g., all SIBs not broadcast in the cell). Using the bitmap, the UE <NUM> may indicate (e.g., by setting the corresponding field/bit to a predefined value) which of the SI(s)/SIB(s) it wants to acquire. In certain embodiments, the UE <NUM> requests system information not only for the current cell, (e.g., cell UE is camped on/connected with) but also for neighboring cells. In one embodiment, the UE <NUM> includes information within the message <NUM> (e.g., SI request message) which indicates that the gNB <NUM> should provide to UE <NUM> all system information used in a predetermined area, covering one or multiple cells. In certain embodiments, the UE <NUM> may include an RRC message within the message <NUM> to convey SI request information. In such an embodiment, the RRC message may contain the SI(s)/SIB(s) that the UE <NUM> wants to acquire.

In various embodiments, some SI may be related to the UE's <NUM> capability and so indicating such capability might provide useful information to the gNB <NUM> as to whether related SI information is to be transmitted to the UE <NUM> in response or not. In certain embodiments, to allow the gNB <NUM> to allocate sufficient uplink resources for transmission of the SI-request bitmap MAC CE in message <NUM>, one or more PRACH preambles may be used to indicate that the purpose of the RACH procedure is for on-demand SI acquisition. In various embodiments, the size of message <NUM> (e.g., the system information request <NUM>) might be different for an initial Access and an SI-request (e.g., message <NUM> for on-demand SI acquisition may only include the system information request message, but no further information like an identity identifying the UE or some buffer status report). In certain embodiments the content of the RACH response message (e.g., RACH message <NUM>), which is sent by gNB in response to receiveing a PRACH preamble may be different for a RACH procedure with the purpose for on-demand SI acquisition than for a RACH procedure for another purpose. In some embodiments, because more than one UE may send an identical reserved PRACH preambles for SI request, a collision of message <NUM> may occur (e.g., multiple UEs are sending SI-request MAC CE (with different content) on UL resources allocated in RACH message <NUM>). Accordingly, in certain embodiments, collision/contention resolution may be used to enable the UE <NUM> to know whether the transmitted SI request was received by gNB <NUM>. In one embodiment, the gNB <NUM> may send in RACH message <NUM> (e.g., the feedback response <NUM>) the SI-request bitmap MAC CE which it received in message <NUM>. This will enable the UE <NUM> to identify whether its SI-request was correctly received by the gNB <NUM>. In various embodiments, the gNB <NUM> could include the requested SIB(s)/SI(s) in the RACH message <NUM> as part of the feedback response <NUM> (e.g., RRC message). In some embodiments, upon reception of RACH message <NUM>, the UE <NUM> may check, by decoding the MAC CE, whether the requested SIB(s)/SI(s) are included (e.g., checking whether the received MAC CE matches the SI-request MAC CE sent in message <NUM>). In embodiments in which the MAC CE matches the SI-request MAC CE, the SIB(s)/SI(s) may be delivered to the RRC. In embodiments in which the MAC CE does not match the request, the UE <NUM> may trigger the SI acquisitions procedure again (e.g., sending PRACH preamble for SI-request, retransmitting the message <NUM>, etc.). Moreover, the UE <NUM> may, upon transmission of message <NUM>, monitor (e.g., during a certain time window, during a predetermined period of time) for a RACH message <NUM>. In situations in which no RACH message <NUM> is received during the predetermined period of time the UE <NUM> may trigger the SI acquisition procedure again (e.g., sending PRACH preamble for SI-request, retransmitting the message <NUM>, etc.).

In various embodiments, the SIB(s)/SI(s) requested by the UE <NUM> may be broadcast (instead of sending them in message <NUM>). In such embodiments, the RACH message <NUM> may include the scheduling information which indicates the timing information for the broadcast of the requested SIB(s)/SI(s). Furthermore, in such embodiments, the UE <NUM> may not read minimum system information in order to acquire the timing information before receiving the broadcasted SIB(s)/SI(s).

In various embodiments, SIB(s)/SI(s) requested by the UE <NUM> may be partly provided by broadcast and partly within RACH message <NUM>. In one embodiment, the RACH message <NUM> may include information indicating which SI(s)/SIB(s) are provided by RACH message <NUM> and which SI(s)/SIB(s) are broadcast (e.g., the UE <NUM> monitors during the SI window associated with these SI(s)/SIB(s) for receiving the broadcast channel).

In one embodiment, the gNB <NUM> may send multiple RACH message <NUM> (e.g., to be provided SI(s)/SIB(s) may not fit within only one downlink transmission). In certain embodiments, an indication is contained within the RACH message <NUM> (e.g., SI feedback response) indicating whether the UE <NUM> should continue monitoring for further downlink transmissions (e.g., further RACH message <NUM> transmissions) for reception of further SI(s)/SIB(s) or whether UE may stop monitoring for further downlink transmissions (e.g., further RACH message <NUM> transmissions). In one embodiment, this indication is a boolean flag. In various embodiments, the RACH message <NUM> may include information indicating whether the UE <NUM>, in response to receiving the RACH message, should initiate an RRC connection establishment procedure or an RRC connection resume procedure.

As may be appreciated, one advantage of including the SI-request bitmap MAC CE in message <NUM> is that collision/contention resolution may be performed on the MAC level. In certain embodiments, the UE <NUM> may, after sending RACH message <NUM> and upon receiving a HARQ acknowledgment as the feedback response <NUM>, read the minimum SI and check whether the gNB <NUM> indicates that the requested SIBs are in response to having received the SI request broadcast in the cell. In such an embodiment, the collision/contention resolution would happen at the minimum SI level.

In some embodiments, the radio network temporary identifier ("RNTI") used for RACH message <NUM> transmission may indicate the on-demand SIB(s) which are either included in message <NUM> (e.g., RRC message) or being broadcast. In such embodiments, a certain number of RNTI(s) (e.g., from the cell RNTI ("C-RNTI") space) may be reserved and associated to a specific SIB or a combination of several SIB(s). Moreover, the UE <NUM> may, upon transmission of message <NUM>, monitor (e.g., during a certain time window, during a predetermined period of time) for a PDCCH addressed to one of those reserved RNTIs. Accordingly, depending on the received PDCCH/RNTI (e.g., the feedback response <NUM>) the UE <NUM> may be aware of whether its SI request sent in message <NUM> was received by the gNB <NUM>. In various embodiments, the RNTI used for RACH message <NUM> may be a common predefined RNTI value. In such embodiments, a common predefined RNTI is used which is specific to the SI-request. Moreover, in such embodiments, no temporary cell RNTI ("T-CRNTI") needs to be allocated/signalled in the RACH response message. In embodiments in which a common RNTI is used, the RACH message <NUM> (e.g., SI feedback message) may not only be addressed to a single UE but may be addressed to multiple UEs which sent a SI request. As such, each UE which sent a SI request may check based on the common RNTI, whether its request was received by gNB <NUM>. In embodiments in which a common RNTI is used for RACH message <NUM>, the SI feedback message conveyed within RACH message <NUM> may contain a bitmap which denotes the SIB(s) for which gNB <NUM> has received a request (e.g., multiple requests from different UEs). As such, each UE which sent a SI request may check, based on the received bitmap, whether its request was received by the gNB <NUM>. In certain embodiments, UEs which have not sent an SI request may monitor for the common RNTI in order to receive the SI feedback message (e.g., RACH message <NUM>) and check the requested SIB(s) so that a UE may not need to request SIB(s) which have been already requested by other UEs.

In certain embodiments described herein, the RACH procedure may be used for the sole purpose of requesting on-demand SI. However, in some embodiments, the UE <NUM> may establish an RRC connection and at the same request on-demand SI, or the UE <NUM> in an inactive state may transmit UL data and at the same time trigger an on-demand SI acquisition procedure. In such embodiments, which are just examples, the UE <NUM> may send the SI-request MAC CE and the RRC connection request message in RACH message <NUM>, or SI-request MAC CE and UL data and potentially some buffer status report ("BSR") MAC CE in RACH message <NUM>. In such embodiments, the gNB <NUM> may distinguish between the different cases (e.g., SI-request, SI-Request plus initial access, Si-request plus UL data) so that the gNB <NUM> may dimension the size of the UL grant accordingly. Accordingly, in some embodiments, PRACH preambles may be reserved for identification of the different cases.

<FIG> illustrates another embodiment of communications <NUM> for transmitting and receiving feedback for a system information request. Specifically, communications <NUM> between a UE <NUM> and a gNB <NUM> are illustrated. The communications <NUM> may facilitate the UE <NUM> requesting on-demand SIBs using a RACH message <NUM> based approach.

In certain embodiments, the gNB <NUM> may transmit a periodic broadcast <NUM> to the UE <NUM>. The periodic broadcast <NUM> may include minimum SI used by the UE <NUM> for communication. In various embodiments, the UE <NUM> may transmit a PRACH preamble <NUM> to the gNB <NUM>. The PRACH preamble <NUM> indicates an SI request to the gNB <NUM> that indicates on-demand SIBs requested by the UE <NUM>. The PRACH preamble <NUM> may be a message <NUM>. As may be appreciated, the on-demand SIBs may not be broadcast (e.g., transmitted) unless requested. In response to the PRACH preamble <NUM>, the gNB <NUM> may transmit a feedback response <NUM> that indicates that the PRACH preamble <NUM> was received by the gNB <NUM>.

In certain embodiments, the PRACH preamble <NUM> is resource specific to an SIB or set of SIBs which the UE <NUM> wants to obtain. In some embodiments, the PRACH preamble <NUM> that is resource specific to each SIB or set of SIBs are reserved and indicated in periodically broadcasted minimum SI. In certain embodiments, the UE <NUM> may request system information not only for the current cell, (e.g., cell UE is camped on/connected with) but also for neighboring cells. In one embodiment, a PRACH preamble <NUM> indicates that the gNB <NUM> should provide to UE <NUM> all system information used in a predetermined area, covering one or multiple cells.

Upon transmission of the PRACH preamble <NUM> (e.g., the SI request preamble), the UE <NUM> may monitor for a feedback message (e.g., the feedback response <NUM>) sent from the gNB <NUM>. The UE <NUM> may monitor for the feedback message during a defined time period (e.g., time window). Upon reception of the feedback message the UE <NUM> may monitor during a signaled SI window for the requested SI (e.g., as indicated in the scheduling information broadcast in the minimum SI).

In the absence of the feedback message, the UE <NUM> may assume that the PRACH transmission was not detected by the gNB <NUM> and may, in certain embodiments, retransmit the PRACH preamble <NUM> (e.g., SI request). In some embodiments, retransmission of the PRACH preamble <NUM> may be with an increased transmission power. In various embodiments, a counter is used and is initially set to zero and increased for each PRACH preamble <NUM> transmission. In certain embodiments, there may be a maximum number of PRACH preamble <NUM> transmission attempts defined. In some embodiments, if the maximum number of PRACH preamble <NUM> transmission attempts is reached the UE <NUM> may indicate to a higher layer a random access problem (e.g., radio link failure procedure might be started such as for an inactive mode).

In certain embodiments, the UE <NUM> may make a maximum number of allowed preamble retransmissions. In such embodiments, the maximum number may be defined in a specification and/or configured by a network using broadcast signaling. In various embodiments, upon not receiving any response and/or acknowledgement, a message <NUM> may indicate a RACH problem to an upper layer. In some embodiments, an upper layer, like RRC in an idle mode, may be unable to make an effective decision according to an LTE specification because the UE <NUM> is in the RRC idle mode. In certain embodiments, an RRC connected UE <NUM> may trigger an RLF procedure when a MAC indicates a RACH problem. In various embodiments, RLF may not be possible for an RRC idle UE <NUM> because there may be no dedicated link. In such embodiments, the UE <NUM> may continuously lose power as the MAC keeps on transmitting a message <NUM> and upper layers do not have a specific solution to stop this situation.

<FIG> is a schematic flow chart diagram illustrating one embodiment of a method <NUM> for performing an action based on a number of transactions reaching a threshold. In some embodiments, the method <NUM> is performed by an apparatus, such as the remote unit <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> includes setting <NUM> a preamble count equal to zero. Moreover, the method <NUM> includes determining <NUM> SIBs required by a remote unit <NUM>. In some embodiments, the method <NUM> may include determining <NUM> whether some of the required SIBs are only provided on demand.

In response to determining <NUM> that none of the require SIBs are only provided on demand, the method <NUM> may acquire <NUM> the SIBs as they are broadcast, and the method <NUM> may end. Moreover, in response to determining <NUM> that some of the required SIBs are only provided on demand, the method <NUM> may determine <NUM> one or more preambles corresponding to the required SIBs that are only available on demand.

In certain embodiments, the method <NUM> may transmit <NUM> a preamble corresponding to a required SIB and may increment the preamble count. In various embodiments, the method <NUM> may determine <NUM> whether an acknowledgment is received in response to transmitting the preamble. In response to determining <NUM> that an acknowledgment is received in response to transmitting the preamble, the method <NUM> may acquire <NUM> the SIBs, and the method <NUM> may end.

In response to determining <NUM> that an acknowledgment is not received in response to transmitting the preamble, the method <NUM> may retransmit <NUM> the preamble. In some embodiments, the method <NUM> may determine <NUM> whether the preamble count (e.g., number of transmissions) equals a maximum preamble count (e.g., predetermined threshold). In response to determining <NUM> that the preamble count does not equal the maximum preamble count, the method <NUM> may return to transmitting <NUM> the preamble and incrementing the preamble count.

Moreover, in response to determining <NUM> that the preamble count equals the maximum preamble count (e.g., the number of transmissions has reached the predetermined threshold), the method <NUM> may indicate <NUM> a RACH problem to an upper layer. In certain embodiments, the method <NUM> may select <NUM> one of four alternatives, and the method <NUM> may end. The four alternatives may include a first alternative, a second alternative, a third alternative, and a fourth alternative.

In the first alternative, a remote unit <NUM> may treat a cell as barred (e.g., inhibit communications with a network unit <NUM>). In such embodiments, the barring may be applied for a certain time that can be specified and/or configured using broadcast signaling. In various embodiments, during a time a cell is treated as barred, a corresponding frequency of the cell may be treated as a lowest priority for cell reselection. In certain embodiments, a remote unit <NUM> may use a different Qoffset value for a cell to facilitate a lower ranking of the cell in cell selection and reselection evaluation (e.g., see 3GPP TS <NUM> v <NUM>. In some embodiments, barring may be performed for a predetermined period of time (e.g., a barring timer). In response to the cell being barred, the remote unit <NUM> may select another cell from a different frequency. In various embodiments, in response to a predetermined period of time expiring, the remote unit <NUM> may use an actual priority of a previously barred cell and may reevaluate cell reselection criteria. In some embodiments, if a cell is reselected after previously being barred, the remote unit <NUM> may request to receive any required SIBs and/or SI messages.

In the second alternative, a remote unit <NUM> may inhibit communications with a cell (e.g., network unit <NUM>) based on a type of system information being requested (e.g., the SI and/or SIBs being requested). In certain embodiments, in response to SIs and/or SIBs not being essential SIBs (e.g., according to RRC), the remote unit <NUM> may refrain from retrying until a certain time elapses (e.g., determined via a prohibit timer). In various embodiments, a prohibit timer may be specified and/or configurable (e.g., in dedicated and/or broadcast signaling). In some embodiments, in response to essential SIBs being requested (e.g., if not all essential SIBs are regularly broadcasted), the remote unit <NUM> may treat a cell as barred and/or may reselect another cell and/or frequency as described in the first alternative. In certain embodiments, essential SIBs in NR may be similar to SIB types in LTE, or essential SIBs in NR may be different than SIB types in LTE.

In the third alternative, a remote unit <NUM> may determine whether to inhibit communications with a network unit <NUM> based on a configuration of the remote unit <NUM> (e.g., leave a decision about inhibiting communications to remote unit <NUM> implementation). In certain embodiments, a remote unit <NUM> may use certain non-essential feature-specific SIBs that are important and/or critical for operation of the remote unit <NUM>. In such embodiments, the remote unit <NUM> may treat a cell as barred while other remote units <NUM> may resend an SI request after expiration of a prohibit timer. In various embodiments, a prohibit timer may be specified and/or configurable (e.g., configurable via dedicated and/or broadcast signaling).

In the fourth alternative, a remote unit <NUM> may perform additional transmissions to a network unit <NUM> (e.g., do nothing different by a MAC continuing message <NUM> transmission). In various embodiments, a remote unit <NUM> internal message <NUM> (e.g., Msg1) transmission count may be defined and the remote unit <NUM> may stop message <NUM> transmission once the transmission count is reached and the RRC layer is informed. For example, the remote unit <NUM> may transmit the message <NUM> times. In such an embodiment, the remote unit <NUM> may increase the power for each transmission until a maximum transmission power is reached.

In another alternative, a network may configure one of the above four alternatives and corresponding parameters (e.g., prohibit timer, redirection information towards a certain target frequency, etc.) using dedicated and/or broadcast signaling.

In some embodiments, if a RAR received on RA-RNTI used to send acknowledgements for SI requests contains a backoff indicator subheader, a remote unit <NUM> may refrain from transmitting a message <NUM> until an indicated backoff timer expires. In certain embodiments, it may be determined whether any and/or all preambles corresponding to message <NUM>, or any and/or all preambles allocated for Si-request purposes are subjected to the backoff timer. In certain embodiments, all preambles may be subjected to the backoff timer if the network has receiving many SI requests and would rather start broadcasting them all. In various embodiments, the network may not wish to receive any message <NUM> with or without an SI-request. In various embodiments, the following options may be used for backoff.

In a first option, a remote unit <NUM> behavior may be specified so that a backoff subheader received on RA-RNTI may be used to send acknowledgements for SI requests. In such embodiments, the remote unit <NUM> may back off all preamble transmissions irrespective of whether the preamble transmissions include SI requests or not.

In a second option, a remote unit <NUM> behavior may be specified so that a backoff subheader received on RA-RNTI may be used to send acknowledgements for SI requests. In such embodiments, the remote unit <NUM> may back off only those preamble transmissions that are reserved for SI requests.

In a third option, a remote unit <NUM> may use a new indication in a backoff MAC subheader to indicate which of the first and second options is to be used. <FIG> is a block diagram illustrating one embodiment of a MAC subheader <NUM>. The new indication may be done using one of the reserved bit 'R' and/or 'A' bits illustrated in <FIG>. In some embodiments, in response to 'A' being set then backoff applies to all preamble transmissions irrespective of whether the preamble transmissions are for SI requests or not; otherwise, in response to the 'A' bit not being set, only those preamble transmissions that are reserved for SI requests may be backed-off.

The method <NUM> may include determining <NUM> whether a number of transmissions to a network unit <NUM> has reached a predetermined threshold. In certain embodiments, the method <NUM> includes, in response to the number of transmissions to the network unit <NUM> reaching the predetermined threshold, performing <NUM> an action selected from a group including: inhibiting communications with the network unit <NUM>; determining a type of system information being requested by the number of transmissions and inhibiting communications with the network unit <NUM> based on the type of system information; determining whether to inhibit communications with the network unit <NUM> based on a configuration of a remote unit <NUM>; and performing additional transmissions to the network unit <NUM>.

In certain embodiments, the number of transmissions to the network unit <NUM> includes a number of times that a preamble is retransmitted to the network unit <NUM> without receiving an acknowledgment. In some embodiments, the method <NUM> includes receiving an indicator indicating the action to perform, wherein performing the action includes performing the action indicated by the indicator. In various embodiments, inhibiting the communications with the network unit <NUM> includes inhibiting the communications with the network unit <NUM> for a period of time.

In one embodiment, the method <NUM> includes receiving information indicating the period of time. In certain embodiments, inhibiting the communications with the network unit <NUM> includes reducing a ranking of the network unit <NUM>. In some embodiments, reducing the ranking of the network unit <NUM> includes reducing the ranking of the network unit <NUM> for a period of time. In various embodiments, inhibiting the communications with the network unit <NUM> includes selecting a different network unit for communications.

In one embodiment, inhibiting the communications with the network unit <NUM> based on the type of system information includes: in response to the type of system information including essential system information, inhibiting the communications with the network unit <NUM> and selecting a different network unit for communications; and in response to the type of system information including non-essential system information, delaying the communications with the network unit <NUM> for a period of time.

In certain embodiments, inhibiting the communications with the network unit <NUM> based on the configuration of the remote unit <NUM> includes: in response to the number of transmissions corresponding to critical information for the remote unit <NUM>, inhibiting the communications with the network unit <NUM> and selecting a different network unit <NUM> for communications; and in response to the number of transmissions corresponding to non-critical information for the remote unit <NUM>, delaying the communications with the network unit <NUM> for a period of time. In some embodiments, performing the additional transmissions to the network unit <NUM> includes performing a predetermined number of additional transmissions to the network unit <NUM>.

<FIG> is a schematic flow chart diagram illustrating another embodiment of a method <NUM> for performing an action based on a number of transactions reaching a threshold. In some embodiments, the method <NUM> is performed by an apparatus, such as the network unit <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> may include determining <NUM> an action selected from a group including: inhibiting communications with a network unit <NUM>; determining a type of system information being requested by a number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit <NUM> based on a configuration of a remote unit <NUM>; and performing additional transmissions to the network unit <NUM>. In various embodiments, the method <NUM> includes transmitting <NUM> information corresponding to the selected action.

In certain embodiments, inhibiting the communications with the network unit <NUM> includes the remote unit <NUM> inhibiting the communications with the network unit <NUM> for a period of time. In some embodiments, the information includes an indication of the period of time. In various embodiments, inhibiting the communications with the network unit <NUM> includes the remote unit <NUM> reducing a ranking of the network unit <NUM>. In one embodiment, the remote unit <NUM> reducing the ranking of the network unit <NUM> includes the remote unit <NUM> reducing the ranking of the network unit <NUM> for a period of time.

In certain embodiments, the information includes a reselection offset for reducing the ranking of the network unit <NUM>. In some embodiments, the information includes a frequency based reselection priority for reducing the ranking of the network unit <NUM>. In various embodiments, inhibiting the communications with the network unit <NUM> includes the remote unit <NUM> selecting a different network unit for communications. In one embodiment, inhibiting the communications with the network unit <NUM> based on the type of system information includes: in response to the type of system information including essential system information, the remote unit <NUM> inhibiting the communications with the network unit <NUM> and selecting a different network unit <NUM> for communications; and in response to the type of system information including non-essential system information, the remote unit <NUM> delaying the communications with the network unit <NUM> for a period of time.

In certain embodiments, inhibiting the communications with the network unit <NUM> based on the configuration of the remote unit <NUM> includes: in response to the number of transmissions corresponding to critical information for the remote unit <NUM>, the remote unit <NUM> inhibiting the communications with the network unit <NUM> and selecting a different network unit <NUM> for communications; and in response to the number of transmissions corresponding to non-critical information for the remote unit <NUM>, the remote unit <NUM> delaying the communications with the network unit <NUM> for a period of time. In some embodiments, performing the additional transmissions to the network unit <NUM> includes the remote unit <NUM> performing a predetermined number of additional transmissions to the network unit <NUM>.

In various embodiments, transmitting the information corresponding to the selected action includes signaling parameters corresponding to the selected action to the remote unit <NUM>. In one embodiment, signaling the parameters corresponding to the selected action to the remote unit <NUM> includes signaling the parameters using a broadcast channel. In certain embodiments, signaling the parameters corresponding to the selected action to the remote unit <NUM> includes signaling the parameters using a dedicated channel.

One method comprises: determining whether a number of transmissions to a network unit has reached a predetermined threshold; and in response to the number of transmissions to the network unit reaching the predetermined threshold, performing an action selected from a group comprising: inhibiting communications with the network unit; determining a type of system information being requested by the number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit.

In certain embodiments, the number of transmissions to the network unit comprises a number of times that a preamble is retransmitted to the network unit without receiving an acknowledgment.

In some embodiments, the method comprises receiving an indicator indicating the action to perform, wherein performing the action comprises performing the action indicated by the indicator.

In various embodiments, inhibiting the communications with the network unit comprises inhibiting the communications with the network unit for a period of time.

In one embodiment, the method comprises receiving information indicating the period of time.

In certain embodiments, inhibiting the communications with the network unit comprises reducing a ranking of the network unit.

In some embodiments, reducing the ranking of the network unit comprises reducing the ranking of the network unit for a period of time.

In various embodiments, inhibiting the communications with the network unit comprises selecting a different network unit for communications.

In one embodiment, inhibiting the communications with the network unit based on the type of system information comprises: in response to the type of system information comprising essential system information, inhibiting the communications with the network unit and selecting a different network unit for communications; and in response to the type of system information comprising non-essential system information, delaying the communications with the network unit for a period of time.

In certain embodiments, inhibiting the communications with the network unit based on the configuration of the remote unit comprises: in response to the number of transmissions corresponding to critical information for the remote unit, inhibiting the communications with the network unit and selecting a different network unit for communications; and in response to the number of transmissions corresponding to non-critical information for the remote unit, delaying the communications with the network unit for a period of time.

In some embodiments, performing the additional transmissions to the network unit comprises performing a predetermined number of additional transmissions to the network unit.

One apparatus comprises: a processor that: determines whether a number of transmissions to a network unit has reached a predetermined threshold; and in response to the number of transmissions to the network unit reaching the predetermined threshold, performs an action selected from a group comprising: inhibiting communications with the network unit; determining a type of system information being requested by the number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit.

In some embodiments, an apparatus comprises a receiver that receives an indicator indicating the action to perform, wherein the processor performing the action comprises the processor performing the action indicated by the indicator.

In one embodiment, an apparatus comprises a receiver that receives information indicating the period of time.

In some embodiments, the processor performing the additional transmissions to the network unit comprises the processor performing a predetermined number of additional transmissions to the network unit.

One method comprises: determining an action selected from a group comprising: inhibiting communications with a network unit; determining a type of system information being requested by a number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit; and transmitting information corresponding to the selected action.

In certain embodiments, inhibiting the communications with the network unit comprises the remote unit inhibiting the communications with the network unit for a period of time.

In some embodiments, the information comprises an indication of the period of time.

In various embodiments, inhibiting the communications with the network unit comprises the remote unit reducing a ranking of the network unit.

In one embodiment, the remote unit reducing the ranking of the network unit comprises the remote unit reducing the ranking of the network unit for a period of time.

In certain embodiments, the information comprises a reselection offset for reducing the ranking of the network unit.

In some embodiments, the information comprises a frequency based reselection priority for reducing the ranking of the network unit.

In various embodiments, inhibiting the communications with the network unit comprises the remote unit selecting a different network unit for communications.

In one embodiment, inhibiting the communications with the network unit based on the type of system information comprises: in response to the type of system information comprising essential system information, the remote unit inhibiting the communications with the network unit and selecting a different network unit for communications; and in response to the type of system information comprising non-essential system information, the remote unit delaying the communications with the network unit for a period of time.

In certain embodiments, inhibiting the communications with the network unit based on the configuration of the remote unit comprises: in response to the number of transmissions corresponding to critical information for the remote unit, the remote unit inhibiting the communications with the network unit and selecting a different network unit for communications; and in response to the number of transmissions corresponding to non-critical information for the remote unit, the remote unit delaying the communications with the network unit for a period of time.

In some embodiments, performing the additional transmissions to the network unit comprises the remote unit performing a predetermined number of additional transmissions to the network unit.

In various embodiments, transmitting the information corresponding to the selected action comprises signaling parameters corresponding to the selected action to the remote unit.

In one embodiment, signaling the parameters corresponding to the selected action to the remote unit comprises signaling the parameters using a broadcast channel.

In certain embodiments, signaling the parameters corresponding to the selected action to the remote unit comprises signaling the parameters using a dedicated channel.

One apparatus comprises: a processor that determines an action selected from a group comprising: inhibiting communications with a network unit; determining a type of system information being requested by a number of transmissions and inhibiting communications with the network unit based on the type of system information; determining whether to inhibit communications with the network unit based on a configuration of a remote unit; and performing additional transmissions to the network unit; and a transmitter that transmits information corresponding to the selected action.

In various embodiments, the transmitter transmitting the information corresponding to the selected action comprises the transmitter signaling parameters corresponding to the selected action to the remote unit.

In one embodiment, the transmitter signaling the parameters corresponding to the selected action to the remote unit comprises the transmitter signaling the parameters using a broadcast channel.

Claim 1:
A method (<NUM>) performed by a remote unit in communication with a network unit, the method comprising:
determining (<NUM>) whether a number of transmissions of a plurality of transmissions to the network unit has reached a predetermined threshold, wherein each transmission of the plurality of transmissions comprises a request for system information; and
in response to the number of transmissions to the network unit reaching the predetermined threshold, performing (<NUM>) an action,
wherein the action is determining a type of system information being requested by the number of transmissions and inhibiting additional transmissions of the plurality of transmissions with the network unit based on the type of system information.