Patent Description:
To meet the demand for wireless data traffic having increased since deployment of fourth generation (<NUM>) communication systems, efforts have been made to develop an improved fifth generation (<NUM>) or pre-<NUM> communication system. Therefore, the <NUM> or pre-<NUM> communication system is also called a 'Beyond <NUM> Network' or a 'Post long term evolution (LTE) System'. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, and analog beam forming, large scale antenna techniques are discussed in <NUM> communication systems. In the <NUM> system, Hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

As technology elements, such as "sensing technology," "wired/wireless communication and network infrastructure," "service interface technology," and "Security technology" have been demanded for IoT implementation, a sensor network, a machine-to-machine (M2M) communication, machine type communication (MTC), and so forth have been recently researched.

For example, technologies, such as a sensor network, MTC, and M2M communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud radio access network (RAN) as the above-described Big Data processing technology may also be considered to be as an example of convergence between the <NUM> technology and the IoT technology.

In the recent years several broadband wireless technologies have been developed to meet the growing number of broadband subscribers and to provide more and better applications and services. The second generation wireless communication system has been developed to provide voice services while ensuring the mobility of users. Third generation wireless communication system supports not only the voice service but also data service. In recent years, the fourth wireless communication system has been developed to provide high-speed data service. However, currently, the fourth generation wireless communication system suffers from a lack of resources to meet the growing demand for high speed data services. So a fifth generation wireless communication system is being developed to meet the growing demand for high speed data services, support ultra-reliability and low latency applications, and support massive machine type communication.

<NPL>, relates to random access procedures for a Narrow Band Internet of Things, NB-IOT.

<CIT> discloses a random access procedure in a wireless communication system which is performed for a specific type of UE.

<NPL> concerns remaining details of random access procedures for MTC, wherein sections <NUM> and <NUM> discuss scheduling and transmission of RAR and CSS usage.

One of the requirements of a next generation system is that it should support flexible network (NW) and user equipment (UE) channel bandwidth (BW). The next generation physical-layer design should allow for fine granularity in terms of next generation (NR) carrier bandwidth. The next generation physical-layer design should be such that devices with different bandwidth capabilities can efficiently access the same NR carrier regardless of the NR carrier bandwidth. The UEs camped on a carrier of certain BW and interested in enhanced mobile broadband may have different channel bandwidths. One of the issues is how to support UEs with different bandwidth capabilities on the same carrier. In the existing system for a given radio access technology (RAT), all UEs camped to a carrier have the same BW as the carrier BW. If the UE does not support same BW as carrier BW then it does not camp on that cell.

The invention is defined by the claims and provides a method according to claim <NUM>, a method according to claim <NUM>, a terminal according to claim <NUM> and a base station according to claim <NUM>.

The present disclosure provides apparatuses and methods for supporting flexible user equipment (UE) bandwidth in a wireless communication system.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the claims.

<FIG> illustrates a contention-based random access (CBRA) procedure according to an embodiment of the present disclosure.

Referring to <FIG>, in operation <NUM>, a user equipment (UE) transmits a random access (RA) preamble to a base station evolved NodeB (eNB). The UE selects one of the available <NUM>-Ncf contention based RA preambles. Ncf is the number of RA preambles reserved for contention free access.

The contention based RA preambles can be optionally partitioned into two groups. If two groups are configured, the UE selects the group based on size of a scheduled transmission (message <NUM>) it can transmit. The initial RA preamble transmission power is set based on open loop estimation after compensating for path loss.

In operation <NUM>, the eNB transmits a random access response (RAR) to the UE in response to the RA preamble. The eNB transmits the RAR on physical downlink shared channel (PDSCH) addressed to an RA-radio network temporary identifier (RA-RNTI). RA-RNTI identifies the time-frequency slot in which RA preamble was detected by the eNB. RAR conveys RA preamble identifier, timing alignment information, temporary cell radio network temporary identifier (C-RNTI) and uplink (UL) grant for message <NUM>. RAR may also include a back off indicator to instruct the UE to back off for a period of time before retrying an RA attempt. RAR is transmitted in an RAR window.

In operation <NUM>, the UE transmits scheduled UL transmission to the eNB in response to the RAR. The UE transmits scheduled UL transmission on physical uplink shared channel (PUSCH). It is used to transmit message, such as radio resource control (RRC) connection request, RRC connection re-establishment request, RRC handover confirm, scheduling request, and the like. It also includes the UE identity (i.e., C-RNTI or SAE-temporary mobile subscriber identity (S-TMSI) or a random number). Hybrid automatic-repeat-request (HARQ) is used for this transmission. This is commonly referred as message <NUM> (MSG3).

In operation <NUM>, the eNB transmits a contention resolution message to the UE. It uses HARQ and is addressed to C-RNTI (if included in message <NUM>) or temporary C-RNTI (UE identity included in message <NUM> is included this case). On successful decoding of this message, HARQ feedback is only sent by the UE which detects its own UE ID (or C-RNTI).

<FIG> illustrates a contention-free random access (CFRA) procedure according to an embodiment of the present disclosure.

Contention free RA procedure is used for scenarios, such as handover where low latency is required, timing advance establishment for a secondary cell (SCell), and the like.

Referring to <FIG>, in operation <NUM>, the eNB assigns to the UE non-contention RA preamble in dedicated signaling. In operation <NUM>, the UE transmits the assigned non-contention RA preamble to the eNB.

In operation <NUM>, the eNB transmits RAR on PDSCH addressed to RA-RNTI. RAR conveys RA preamble identifier and Timing alignment information. RAR may also include UL grant. RAR is transmitted in RAR window similar to contention based RA procedure. Contention free RA procedure terminates after receiving the RAR.

<FIG> illustrates signal timing between a UE and a base station in a random access procedure according to an embodiment of the present disclosure.

Referring to <FIG>, the UE transmits RA preamble (or a random access channel (RACH) preamble) to the eNB at subframe (SF) 'x'. The eNB transmits RAR including grant for MSG3 to the UE at subframe 'n'. RAR is transmitted in a RAR window. As shown in <FIG>, RAR window starts at subframe 'x+<NUM>' for RA preamble transmitted in subframe 'x'. RAR window size is configurable (for example, <NUM> SFs). Thereafter, the UE transmits MSG <NUM> to the eNB at subframe 'n+<NUM>' for RAR transmitted in subframe 'n'.

In new radio (NR), CBRA procedure is needed at least for initial access. During initial access dedicated RA preamble assignment is not possible. In addition to the CBRA procedure, CFRA should also be supported for scenarios, such as handover, scheduling request transmission, and the like, where low latency is required.

One of the requirements of a next generation system is that it should support flexible NW and UE channel bandwidth. The next generation physical-layer design should allow for fine granularity in terms of NR carrier bandwidth. The next generation physical-layer design should be such that devices with different bandwidth capabilities can efficiently access the same NR carrier regardless of the NR carrier bandwidth.

The UEs camped on a carrier of certain bandwidth (BW) and interested in enhanced mobile broadband may have different channel bandwidths. One of the issues is how to support UEs with different bandwidth capabilities on the same carrier. In the existing system for a given radio access technology (RAT), all UEs camped to a carrier have the same BW as the carrier BW. If the UE does not support the same BW as the carrier BW then it does not camp on that cell.

A method to support UEs with different bandwidth capabilities on the same NR carrier during a random access procedure is needed.

<FIG> illustrates a CBRA procedure in a next generation NR according to an embodiment of the present disclosure.

The high level operation for contention based RA procedure in NR are shown in <FIG>.

There is a need to identify what is required to support UEs with different channel bandwidth capabilities on the same NR carrier during each operation of RA procedure.

Referring to <FIG>, in operation <NUM>, a UE transmits a RA preamble to a base station (NR-NB). The channel bandwidth of a UE transmitting the RA preamble can be smaller than the NR carrier bandwidth. Also different UEs may have different channel bandwidth for transmission/reception on the same NR carrier.

In order to support UEs with different channel bandwidth capabilities on the same NR carrier, physical random access channel (PRACH) bandwidth in NR should be less than or equal to minimum supported UE channel bandwidth in NR. This ensures that every UE is able to transmit RA preamble irrespective of its supported channel bandwidth during initial access. For example, if B1, B2, and B3 are various UE channel bandwidths supported in system such that B1>B2>B3, then PRACH bandwidth should be less than or equal to B3.

In operation <NUM>, the NR-NB transmits a RAR to the UE in response to the RA preamble. NR-NB transmits RAR in response to successfully received RA preamble. NR-NB transmits new radio-physical downlink control channel (NR-PDCCH) (similar to a long term evolution (LTE) PDCCH) addressed to RA-RNTI to indicate RAR transmitted in NR-PDSCH (similar to LTE PDSCH).

The receiving (RX) channel bandwidth of a UE waiting for RAR after transmitting the RA preamble can be smaller than the NR carrier bandwidth. UE can monitor the NR-PDCCH for RAR during the RAR window only over the RX channel bandwidth supported by it. UE can also receive the RAR only over the RX channel bandwidth supported by it. So, the NR-PDCCH for RAR and RAR should be transmitted by NR-NB over bandwidth less than or equal to RX channel bandwidth of the UE.

In operation <NUM>, the UE transmits scheduled UL transmission (MSG3) to the NR-NB in response to the RAR. The resources for initial transmission of MSG3 are provided in RAR. Resources for retransmission of MSG3 are indicated using NR-PDCCH. The TX and RX channel bandwidth of a UE can be smaller than the NR carrier bandwidth. So, the NR-PDCCH for MSG3 retransmission should be transmitted by NR-NB over bandwidth less than or equal to RX channel bandwidth of the UE. Resources for MSG3 transmission should be allocated to the UE over a bandwidth less than or equal to a transmit (TX) channel bandwidth of a UE.

In operation <NUM>, the NR-NB transmits a contention resolution message (MSG4) to the UE. NR-NB similar to LTE transmits the MSG4 in response to successfully received MSG3. Resources for (re-)transmissions of MSG4 are indicated using NR-PDCCH. The TX and RX channel bandwidth of a UE can be smaller than the NR carrier bandwidth. So, the NR-PDCCH for MSG4 (re-)transmissions should be transmitted by NR-NB over bandwidth less than or equal to RX channel bandwidth of the UE. Resources for MSG4 transmission should be allocated to the UE over bandwidth less than or equal to TX channel bandwidth of the UE.

In this method frequency resources (or bandwidth part/sub-band wherein the carrier bandwidth is divided into multiple bandwidth parts/sub-bands in frequency domain) corresponding to minimum supported UE channel bandwidth in system for transmitting and receiving PRACH, NR-PDCCH, RAR, MSG3 and MSG <NUM> is signaled in broadcast signaling. For example, if B1, B2 and B3 are various UE channel bandwidths supported in system such that B <NUM>>B2>B3 then minimum supported UE channel bandwidth in system is equal to B3. If the TX and RX minimum supported UE channel BW in system are different then frequency resources (or bandwidth part/sub-band) corresponding to minimum supported UE TX channel bandwidth and frequency resources (or bandwidth part/sub-band) corresponding to minimum supported UE RX channel bandwidth is indicated independently.

In an embodiment these frequency resources (or bandwidth part/sub-band) is indicated in master information base (MIB) in broadcast channel (BCH) or system information block (SIB). In another embodiment of the present disclosure, the frequency resources (or bandwidth part/sub-band) can be same as the frequency resources (or bandwidth part/sub-band) in which BCH is received or at an offset from frequency resources (or bandwidth part/sub-band) in which BCH is received. The offset can be signaled in MIB of BCH. UE receives the NR-PDCCH, RAR and MSG4 over the RX frequency resources (or bandwidth part/sub-band) in time intervals for receiving NR-PDCCH, RAR and MSG4. UE transmits the RA preamble and MSG3 over the TX frequency resources (or bandwidth part/sub-band) in time intervals for RA preamble and MSG3 transmissions.

In order to indicate the frequency resources (or bandwidth part/sub-band), in an embodiment of the present disclosure, NR carrier BW can be divided in frequency domain in several sub-bands or bandwidth parts wherein BW of each sub-band or bandwidth part is less than or equal to minimum supported UE channel bandwidth in system. These sub-bands or bandwidth parts can be logically numbered and sub-band number or bandwidth part number for transmitting and receiving PRACH, NR-PDCCH, RAR, MSG3 and MSG <NUM> is indicated in broadcast signaling. If the TX and RX minimum supported UE channel BW in system are different then both TX sub-band number or TX bandwidth part number and RX sub-band number or RX bandwidth part number are indicated independently.

This approach is simple. However it limits the number of concurrent random accesses.

<FIG> illustrates a method for supporting UEs with different bandwidth in a CBRA procedure according to an embodiment of the present disclosure.

Referring to <FIG>, in operation <NUM>, a user equipment (UE-X) transmits a RA preamble to a base station (NR-NB). The UE transmits the RA preamble over a PRACH resource. PRACH bandwidth is less than or equal to minimum supported UE TX channel bandwidth in the system. For example, if B1, B2 and B3 are various UE TX channel bandwidths supported in system such that B <NUM>>B2>B3 then minimum supported UE TX channel bandwidth in system is equal to B3.

NR-NB does not know the supported channel bandwidth of UE-X from which it has received the RA preamble. In operation <NUM> and <NUM>, NR-PDCCH for RAR and RAR is transmitted by NR-NB over bandwidth less than or equal to minimum supported UE RX channel bandwidth in the system. For example, if B1, B2 and B3 are various UE RX channel bandwidths supported in system such that B1>B2>B3 then NR-PDCCH for RAR and RAR is transmitted by NR-NB over bandwidth ≤ Bmin = B3. UE monitors NR-PDCCH for RAR and RAR over minimum supported UE RX channel bandwidth in the system.

There can be several locations in frequency domain to monitor NR-PDCCH for RAR over minimum supported UE RX bandwidth. On a NR carrier, the location of frequency resources or bandwidth part/sub-band (identified by bandwidth part/sub-band number/index)for monitoring NR-PDCCH for RAR wherein the bandwidth of frequency resources or bandwidth part/sub-band is equal to minimum supported UE RX channel bandwidth can be signaled in system information (e.g., MIB or SIB). Alternately, the location of frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH for RAR can be same as or relative to the location of frequency resources or bandwidth part/sub-band in which RA preamble is transmitted. Alternately, the location of frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH for RAR can be same as or relative to the location of frequency resources or bandwidth part/sub-band in which MIB or broadcast information is received.

RAR frequency resources and/or bandwidth part/sub-band (identified by bandwidth part/sub-band number/index) for receiving RAR wherein the bandwidth of frequency resources or bandwidth part/sub-band is equal to minimum supported UE RX channel bandwidth is indicated in NR-PDCCH.

In operation <NUM>, the UE-X transmits Scheduled UL transmission (or MSG3) to the NR-NB. The NR-NB does not know the supported TX channel bandwidth of the UE. So for MSG3 transmission, NR-NB allocates frequency resources in RAR, corresponding to less than or equal to minimum supported UE TX channel bandwidth. In operation <NUM>, for MSG3 retransmissions, the UE needs to monitor NR-PDCCH. The frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH for MSG3 are indicated in RAR wherein the bandwidth of frequency resources or bandwidth part/sub-band is equal to minimum supported UE RX channel bandwidth in system. Alternately, in operation <NUM>, the location of frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH for MSG3 corresponding to minimum supported UE TX channel bandwidth in system can be signaled in system information. MSG3 retransmission frequency resources and/or bandwidth part/sub-band corresponding to minimum supported UE TX channel bandwidth in system is indicated in NR-PDCCH.

In operation <NUM>, the NR-NB transmits contention resolution message (or MSG4) to the UE-X. For receiving MSG4 (re-)transmissions, the UE needs to monitor NR-PDCCH. The frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH can be indicated in RAR wherein the bandwidth of frequency resources or bandwidth part/sub-band is equal to minimum supported UE RX channel bandwidth in system. Alternately, the location of frequency resources or bandwidth part/sub-band for monitoring NR-PDCCH for MSG4 corresponding to minimum supported UE RX channel bandwidth can be signaled in system information. The frequency resources and/or bandwidth part/sub-band for MSG4 (re-)transmission can be indicated in NR-PDCCH according to minimum supported UE RX channel bandwidth.

According to an embodiment of the present disclosure, the UE can report its supported RX channel bandwidth in MSG3. The frequency resources and/or bandwidth part/sub-band (identified by bandwidth part/sub-band number/index) for MSG4 (re-)transmission can be indicated in NR-PDCCH according to supported RX channel bandwidth of the UE.

The location of frequency resources or bandwidth part/sub-band (identified by bandwidth part/sub-band number/index) for monitoring NR-PDCCH for MSG4 corresponding to each supported UE channel bandwidth can be signaled in system information or RAR. So UE can monitor NR-PDCCH for MSG4 over its supported RX channel bandwidth. NR-NB transmits NR-PDCCH for MSG4 in the frequency resources or bandwidth part/sub-band corresponding to UEs supported RX channel bandwidth.

In an embodiment TX and RX channel BW of the UE can be same and can be referred as channel BW of the UE. In another embodiment of the present disclosure, TX and RX channel BW of the UE can be different and minimum of TX and RX channel BW of the UE can referred as channel BW of the UE in above operation.

Referring to <FIG>, in operation <NUM>, the UE transmits the RA preamble over a PRACH resource. The RA preamble(s) and/or time and/or frequency resources for RA preamble transmission corresponding to each supported UE channel bandwidth is signaled in system information. UE selects the RA preamble and/or time and/or frequency resource for RA preamble transmission according to a channel bandwidth supported by it. NR-NB can know the channel bandwidth supported by the UE on receiving the RA preamble transmission.

In operation <NUM>, NR-PDCCH for RAR is transmitted over channel bandwidth less than or equal to a channel bandwidth supported by the UE. For example, if B1, B2, and B3 are various UE bandwidths supported in system such that B1>B2>B3, Bc is carrier bandwidth, UE1 which has transmitted RA preamble has channel bandwidth B2, then, in operation <NUM>, NR-PDCCH for RAR and RAR is transmitted by NR-NB over channel bandwidth less than or equal to B2. UE monitors NR-PDCCH for RAR and RAR over its supported UE channel bandwidth.

There can be several locations in frequency domain to transmit/receive NR-PDCCH for RAR over supported UE channel bandwidth. The location of frequency resources or one or more bandwidth parts/sub-bands for receiving NR-PDCCH for RAR corresponding to each supported UE channel bandwidth can be signaled in system information. The bandwidth of each bandwidth part or sub band can be minimum supported UE channel bandwidth. For each supported UE channel bandwidth one or more bandwidth part or sub bands can be indicated.

RAR frequency resources over supported UE channel bandwidth is indicated in NR-PDCCH.

In operation <NUM>, the UE transmits scheduled UL transmission (or MSG3) to the NR-NB. In this approach NR-NB knows the UE supported channel bandwidth. So it allocates frequency resources corresponding to UE's channel bandwidth in RAR. In operations <NUM> and <NUM>, for MSG3 retransmissions, the UE needs to monitor NR-PDCCH. In operation <NUM>, the frequency resources or one or more bandwidth parts/sub-bands for monitoring NR-PDCCH are also indicated in RAR according to the UE supported channel bandwidth. The frequency resources for MSG3 retransmission are indicated in NR-PDCCH according to the UE supported channel bandwidth.

In operation <NUM>, the NR-NB transmits contention resolution message (or MSG4) to the UE. For receiving MSG4 (re-)transmissions, the UE need to monitor NR-PDCCH. The frequency resources or one or more bandwidth parts/sub-bands for monitoring NR-PDCCH are indicated in RAR according to the UE supported channel bandwidth. The frequency resources for MSG4 (re-)transmission are indicated in NR-PDCCH according to the UE supported channel bandwidth.

There can be several locations in frequency domain to transmit/receive NR-PDCCH for RAR over supported UE RX channel bandwidth. The location of frequency resources or one or more bandwidth parts/sub-bands for receiving NR-PDCCH for RAR corresponding to each supported UE RX channel bandwidth can be signaled in system information.

RAR resources over supported UE channel bandwidth is indicated in NR-PDCCH.

c) Scheduled UL Transmission or MSG3: In this approach NR-NB does not know the UE supported TX channel bandwidth. So it allocates resources corresponding to minimum supported UE channel bandwidth in RAR. For MSG3 retransmissions, the UE needs to monitor NR-PDCCH. The frequency resources or one or more bandwidth parts/sub-bands for monitoring NR-PDCCH are also indicated in RAR according to the UE supported RX channel bandwidth. The frequency resources for MSG3 retransmission are indicated in NR-PDCCH according to minimum supported channel bandwidth.

d) Contention Resolution Message or MSG4: For receiving MSG4 (re-)transmissions, the UE need to monitor NR-PDCCH. The frequency resources or one or more bandwidth parts/sub-bands for monitoring NR-PDCCH are indicated in RAR according to the UE supported channel bandwidth. The frequency resources for MSG4 (re-)transmission are indicated in NR-PDCCH according to the UE supported channel bandwidth.

<FIG> illustrates a timeline for beam feedback using a random access procedure according to an embodiment of the present disclosure.

Referring to <FIG>, beam feedback is sent in MSG3. Beam change command with beam ID is received in MSG4. Beam change is applied N subframes after HARQ ACK for MSG4.

<FIG> illustrates beam usage during a random access procedure according to an embodiment of the present disclosure.

Referring to <FIG>, beam Usage during RA procedure is shown in <FIG>. During RA procedure best or suitable TX/RX beam are used by the UE which can be different from serving TX/RX beam used for uplink/downlink (UL/DL) data TX/RX. The issue is that UE misses UL and DL data during a random access procedure as UL/DL data is TX/RX based on serving TX/RX beam.

Referring to <FIG>, in a method of proposed disclosure the modified beam usage during a random access procedure for beam feedback is illustrated in <FIG>. Best/suitable TX beam for RA is used in SF (or time slot) where RACH Preamble, MSG3, HARQ feedback for MSG4 are transmitted. Best/suitable RX beam for RA is used from start of RAR window until UE receives RAR. Best/suitable RX beam is used in SF(s) (or time slots) where HARQ feedback for MSG3 and MSG4 are received or likely to be received. In other SFs (or time slots) UE uses serving TX/RX beam.

Referring to <FIG>, in alternate method of proposed disclosure the modified beam usage during a random access procedure for beam feedback is illustrated in <FIG>. After receiving MSG3 eNB knows the UE and its serving beam. If serving beam is good and included in MSG3, it can transmit using serving beam and UE can receive using serving beam. Best/suitable TX beam is used in SF (or time slot) where RACH Preamble, MSG3 are transmitted. Best/suitable RX beam is used from start of RAR window until UE receives RAR. Best/suitable RX beam is used in SF(s) (or time slots) where HARQ feedbacks for MSG3 are received or likely to be received. In other SFs (or time slots) UE uses serving TX/RX beam.

Referring to <FIG>, the UE may include a transceiver (or transmission/reception unit <NUM>, a controller <NUM>, and a storage unit <NUM>. In the present disclosure, controller <NUM> may be defined as a circuit or an application specific integrated circuit or at least one processor.

Transceiver <NUM> may transmit and receive signals with other network entities. Transceiver <NUM> may receive system information from, for example, a base station and may receive a synchronization signal or a reference signal.

Controller <NUM> may control the overall operation of the UE according to the embodiment of the present disclosure. For example, Controller <NUM> may control the signal flow between each block to perform the operation according to the flowcharts described above. In detail, controller <NUM> may control operations proposed by the present disclosure to support flexible UE bandwidth during a random access procedure.

Controller <NUM> is coupled with transceiver <NUM> and controller <NUM> is configured to transmit, to a base station, random access preamble over a first bandwidth selected among a plurality of channel bandwidths of the UE, to receive, from the base station, random access response over a second bandwidth selected among the plurality of channel bandwidths of the UE in response to the random access preamble, and to transmit, to the base station, a scheduled transmission message (message <NUM>) over a third bandwidth selected among the plurality of channel bandwidths of the UE.

According to an embodiment of the present disclosure, the first bandwidth is less than or equal to minimum UE TX channel bandwidth among the plurality of channel bandwidths of the UE, the second bandwidth is less than or equal to minimum UE RX channel bandwidth among the plurality of channel bandwidths of the UE, and the third bandwidth is less than or equal to the minimum UE TX channel bandwidth among the plurality of channel bandwidths of the UE.

According to an embodiment of the present disclosure, the minimum UE TX channel bandwidth is identical with the minimum UE RX channel bandwidth.

Controller <NUM> is configured to monitor NR-PDCCH over bandwidth less than or equal to the minimum UE RX channel bandwidth.

According to an embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is signaled in system information. According to another embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is same as or relative to a location of frequency resources in which random access preamble is transmitted. According to the other embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is same as or relative to a location of frequency resources in which MIB or broadcast information is received.

Controller <NUM> is configured to receive, from the base station, a contention resolution message over fourth bandwidth selected among the channel bandwidths of the UE, wherein the fourth bandwidth is less than or equal to minimum UE RX channel bandwidth among a plurality of channel bandwidths of the UE.

According to an embodiment of the present disclosure, the scheduled transmission message (message <NUM>) includes information on supported RX channel bandwidth of the UE.

According to an embodiment of the present disclosure, controller <NUM> is configured to receive system information including resources for random access preamble transmission corresponding to each supported UE channel bandwidth. Controller <NUM> is configured to select the first bandwidth for transmitting the random access preamble according to a channel bandwidth supported by the UE.

Storage unit <NUM> may store at least one of information transmitted and received through the transceiver <NUM> and information generated through controller <NUM>.

<FIG> illustrates a structure of a base station according to an embodiment of the present disclosure.

Referring to <FIG>, the base station may include a transceiver (transmission/reception unit <NUM>), a controller <NUM>, and a storage unit <NUM>. In the present disclosure, controller <NUM> may be defined as a circuit or an application specific integrated circuit or at least one processor.

Transceiver <NUM> may transmit and receive signals with other network entities. Transceiver <NUM> may transmit system information to the UE, for example, and may transmit a synchronization signal or a reference signal.

Controller <NUM> may control the overall operation of the base station according to the embodiment of the present disclosure. For example, controller <NUM> may control the signal flow between each block to perform the operation according to the flowcharts described above. More particularly, controller <NUM> may control operations proposed by the present disclosure to support flexible UE bandwidth during a random access procedure.

Controller <NUM> is coupled with transceiver <NUM> and is configured to receive, from the UE, random access preamble over a first bandwidth selected among a plurality of channel bandwidths of the UE, to transmit, to the UE, random access response over a second bandwidth selected among the plurality of channel bandwidths of the UE in response to the random access preamble, and to receive, from the UE, a scheduled transmission message (message <NUM>) over a third bandwidth selected among the plurality of channel bandwidths of the UE.

According to an embodiment of the present disclosure, NR-PDCCH is monitored over bandwidth less than or equal to the minimum UE RX channel bandwidth.

According to an embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is signaled in system information. According to another embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is same as or relative to a location of frequency resources in which random access preamble is transmitted. According to another embodiment of the present disclosure, the location of frequency resources for monitoring the NR-PDCCH is same as or relative to a location of frequency resources in which MIB or broadcast information is received.

Controller <NUM> is configured to transmit, to the UE, a contention resolution message over fourth bandwidth selected among the channel bandwidths of the UE, wherein the fourth bandwidth is less than or equal to minimum UE RX channel bandwidth among the plurality of channel bandwidths of the UE.

According to an embodiment, the scheduled transmission message (message <NUM>) includes information on supported RX channel bandwidth of the UE.

According to an embodiment, controller <NUM> is configured to transmit system information including resources for random access preamble transmission corresponding to each supported UE channel bandwidth. The first bandwidth for transmitting the random access preamble is selected according to a channel bandwidth supported by the UE.

The storage unit <NUM> may store at least one of information transmitted/received through transceiver <NUM> and information generated through the controller <NUM>.

Claim 1:
A method performed by a terminal in a wireless communication system, the method comprising:
receiving, from a base station, a system information block, SIB, including information on frequency resources for a random access procedure, wherein the frequency resources include a first frequency resource for monitoring a physical downlink control channel, PDCCH, for a random access response, RAR, and a second frequency resource for monitoring a PDCCH for a contention resolution message;
transmitting, to the base station, a random access preamble of the random access procedure;
receiving, from the base station, first downlink control information, DCI, associated with the RAR by monitoring the PDCCH for the RAR based on the first frequency resource;
transmitting, to the base station, a physical uplink shared channel, PUSCH, based on an uplink grant which is received on a physical downlink shared channel, PDSCH, corresponding to the first DCI associated with the RAR; and
receiving, from the base station, second DCI associated with the contention resolution message by monitoring the PDCCH for the contention resolution message based on the second frequency resource,
wherein a reception channel bandwidth of the terminal is less than a carrier bandwidth of a serving cell of the base station, and
wherein a bandwidth of the PDCCH for the RAR and a bandwidth of the PDCCH for the contention resolution message is less than the reception channel bandwidth of the terminal.