METHOD AND APPARATUS FOR DYNAMIC PDCCH MONITORING GROUPS SWITCHING

The apparatus of wireless communication includes a UE and a base station. The base station may transmit, to the UE, a configuration for a plurality of PDCCH monitoring groups for monitoring different sets of search spaces. The plurality of PDCCH monitoring groups may include a first PDCCH monitoring group with a first number of PDCCH monitoring occasions and a second PDCCH monitoring group with a second number of PDCCH monitoring occasions different from the first number. The base station may determine which PDCCH monitoring group to send a PHCCH, and transmit the PDCCH to the UE. The UE may determine to monitor search spaces of the PDCCH monitoring group, and monitor search spaces corresponding to the PDCCH monitoring group. The UE may switch between the first and second PDCCH monitoring groups based on a condition or an indication from the base station.

BACKGROUND

Technical Field

The present disclosure relates generally to communication systems, and more particularly, to a method and apparatus for dynamically switching physical downlink control channel (PDCCH) monitoring groups.

INTRODUCTION

SUMMARY

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE) and a base station. The base station may transmit, to the UE, a configuration for a plurality of PDCCH monitoring groups for monitoring different sets of search spaces. The plurality of PDCCH monitoring groups may include a first PDCCH monitoring group with a first number of PDCCH monitoring occasions and a second PDCCH monitoring group with a second number of PDCCH monitoring occasions different from the first number. The base station may determine which PDCCH monitoring group to send a PDCCH, and transmit, using the determined PDCCH monitoring group, the PDCCH to the UE. The UE may determine to monitor search spaces of the PDCCH monitoring group, and monitor search spaces corresponding to the PDCCH monitoring group. The UE may switch between the first and second PDCCH monitoring groups based on a condition or an indication from the base station. The condition may include at least one of an amount of communication traffic, an expected amount of communication traffic, a characteristic of the communication traffic, a temperature, a time, or a light detection. The indication from the base station may be received in a downlink control information (DCI) or implicitly through one of a minimum K0or a minimum K2value. The UE may transmit the request to change the PDCCH monitoring group to monitor to the base station.

DETAILED DESCRIPTION

Referring again toFIG.1, in certain aspects, the UE104and the base station180may be configured to dynamically switch between physical downlink control channel (PDCCH) monitoring groups (198). Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

At least one of the TX processor368, the RX processor356, and the controller/processor359may be configured to perform aspects in connection with198ofFIG.1. At least one of the TX processor316, the RX processor370, and the controller/processor375may be configured to perform aspects in connection with198ofFIG.1.

Unlicensed Spectrum of NR may be referred to as NR-U. In the NR-U, dynamic PDCCH monitoring group switching is designed to support the functionality to switch between mini-slot based monitoring outside a channel occupancy time (COT) and inside the COT. A channel occupancy time is a sum of packet transfer time of each transmission of the packet until the packet is successfully been transmitted or the packet is dropped as a result of an undeliverable failure. The packet transfer time is defined as a total time required to transfer a data packet, which may include a sum of i) the transmission time of the data packet, ii) the transmission time of acknowledge (ACK) packets when necessary, iii) propagation delays for both the data and ACK packets, and iv) the inter-frame idle periods necessary for a channel to be idle before accessing the channel.

A radio resource control (RRC) may configure multiple PDCCH monitoring groups for transmitting PDCCH to the UE and the UE may dynamically switch among the monitoring groups. That is, the base station may transmit a RRC message to the UE to configure a plurality of PDCCH monitoring groups, and the UE may dynamically switch between the monitoring groups. The PDCCH monitoring groups may be associated with at least one search space. The search spaces for receiving the PDCCH may be UE-specific. That is, the UE may be configured to monitor the UE-specific search spaces associated to the PDCCH monitoring groups indicated by the RRC message to receive the PDCCH. The search space sets that are not part of the configured groups (e.g., a common search space (SS) set) will always be monitored by the UE regardless of the search space set indication. A single search space set may be part of more than one group.

For example, the multiple PDCCH monitoring groups may include group 0 and group 1. The UE-specific search spaces only associated with the group 0 may be monitored by the UE when the group 0 is active. The UE-specific search spaces only associated with the group 1 may be monitored by the UE when the group 1 is active. The UE-specific search spaced associated with both the group 0 and group 1, or The common search space set not associated with the group 0 or the group 1 may be always monitored by the UE.

An example of dynamic switching of PDCCH monitoring groups is illustrated in table A as provided below. Table A illustrates an example DL channel, including three different search spaces SSA, SSB, and SSC, and two PDCCH monitoring groups group0 and group1.

For industry internet of things (IoT), the industry IoT terminals may have variable service patterns. For example, at some specific time, massive number of terminals may need to be connected in the same slot, or the terminals may require low latency service. For another example, multiple sensors may share a single transmit/receiver, while different sensors may have different packet patterns.

Dynamic PDCCH monitoring groups switching (or automatic PDCCH monitoring group switching) can be used for industry IoT to improve the service quality. The automatic PDCCH monitoring group switching pattern may have a pre-determined time pattern, based on the use cases such as a deterministic traffic pattern. That is, the automatic PDCCH monitoring group switching may be based on various conditions. For example, the dynamic PDCCH monitoring group switching may be based on one of an amount of communication traffic, an expected amount of communication traffic, a characteristic of the communication traffic, temperature, time, or light detection. The UE may also provide a request to the base station to switch, based on the use cases that the UE knows there is an urgent traffic coming, triggered by the UL traffic. Here, the urgent traffic may refer to traffic that is delay sensitive, and therefore, the base station and the UE may switch to the PDCCH monitoring group having a shorter periodicity to transmit the PDCCH and monitor to receive the PDCCH.

Different kinds of sensors are used in industrial IoT system. Different types of the sensors may have different communication patterns with different parameters and functions such as temperature measured, and light detection, etc. Dynamically switching the monitoring group in the event-based manner may improve the communication performance.

According to a first aspect of the disclosure, a PDCCH monitoring group may be switch automatically based on a pre-determined pattern. For example, there may be a deterministic traffic pattern in which the amount of traffic changes from a first amount of traffic to a second amount of traffic. That is, the base station may determine the search spaces corresponding to one of the PDCCH monitoring groups based on a pattern in which to transmit the PDCCH to the UE, and the UE may determine to monitor the search spaces corresponding to the one of the PDCCH monitoring groups based on the pattern. For example, the amount of data traffic may vary in a deterministic pattern and the base station and the UE may select one of the monitoring groups based on certain characteristics or needs of the data traffic amounts. The pre-determined pattern may be known to both the base station and the UE. That is, the UE and the base station may share the pre-determined pattern, such that the UE and the base station may switch among the PDCCH monitoring groups without using any signaling to initiate the switching between the monitoring groups. Accordingly, the PDCCH monitoring group may be dynamically switched without an increased signaling overhead.

In another example, the base station may transmit an indication to UE to trigger the dynamic switching of the PDCCH monitoring group. The indication from the base station to the UE may be implemented to override the pre-determined pattern. The indication from the base station to the UE may help avoid or reduce a mismatch between the base station and the UE with respect to the monitoring group and/or when to switch monitoring groups. For example, at a specific time, the base station and the UE may know that there is urgent traffic coming, which requires the UE and the base station to switch to a search space with a shorter periodicity. However, if the UE does not receive the indication from the base station to switch the search space, the UE may continue to use the original search space with longer periodicity since the base station had not decide to switch for some reasons, such as limitation in the resources. That is, the use of the indication allows the base station and the UE to continue using the existing search space when the base station determines that there is not sufficient resources to switch to the other search space.

According to a second aspect of the disclosure, the UE may send a switching request to the base station. That is, the switching of the search spaces may be triggered by the UE based on the UL traffic. For example, when the UE knows that there is urgent traffic coming, the UE may determine to switch to the PDCCH monitoring group with a shorter periodicity and with more PDCCH monitoring occasions.

For example, the UE may transmit the switch request using a new format of a medium access control (MAC) control element (CE) (MAC-CE). The new MAC-CE may carry information known by the UE or to indicate that the UE detects delay sensitive DL data is coming. The new MAC-CE may be used to signal to the base station to switch to more frequent DL scheduling to detect delay sensitive DL data.

In another example, the UE may transmit the request to switch the search spaces via a BSR-CE.FIG.4illustrates examples of the BSR-CE according to aspects of the present disclosure.

Referring toFIG.4, the UE may transmit the switch request using a short BSR-CE or a long BSR-CE. The short BSR-CE410may include 3 bits for a logical channel group (LCG) ID (LCG ID) and 5 bits for the buffer size. The UE may use one bit, for example, the 5thbit following the 4 bits allocated for the buffer size to transmit the switch request to the base station. Since industrial IoT devices may not require a large buffer size, the UE may use the remaining bit to indicate which PDCCH monitoring group the UE wants to switch to.FIG.4illustrates that the UE may transmit the switch request in the 4th bit of the short BSR-CE410, but the embodiments are not limited thereto, and the UE may use any one bit of the 5 bits allocated for the buffer size in the short BSR-CE410.

The long BSR-CE420may include 8 bits for the LCG ID. The UE may transmit the switch request via the bits allocated for the LCGs. For example, the long BSR-CE420illustrates that the switch request may be transmitted in both the LCG7 and the LCG6 to support between more than two groups. Since the industrial IoT devices may not require a large number of LCG IDs, the UE may use the remaining bits in the unused LCG IDs to indicate which PDCCH monitoring group the UE wants to be in, without changing the buffer fields.FIG.4illustrates that the UE may transmit the switch requests in the LCG6 and the LCG7 bits of the LCG ID of the long BSR-CE420, but the embodiments are not limited thereto, and the UE may use any bits of the LCG ID of the long BSR-CE420.

According to a third aspect of the disclosure, the base station may indicate the switching of the PDCCH monitoring group using a minimum K0value and/or a minimum K2value. In the NR-U, the base station may trigger the switching of the PDCCH monitoring group using explicit and implicit conditions. Particularly, the base station may explicitly instruct the UE to switch the PDCCH monitoring group using a dedicated bit included in DCI sent via PDCCH or group common (GC) PDCCH (GC-PDCCH). The base station may implicitly instruct the UE to switch the PDCCH monitoring group using a COT start detection and COT end. In addition to using the mechanisms mentioned above to trigger the switching, the minimum K0value and/or the minimum K2value may also be used to trigger the switching.

The minimum K0value and/or the minimum K2value may be configured by RRC per bandwidth part (BWP) and/or 1-bit in the DCI to indicate change between up to 2 preconfigured values. The K0may be used to calculate the time domain allocation for a physical downlink shared channel (PDSCH). The K2may be used to calculate the time domain allocation for a physical uplink shared channel (PUSCH). Accordingly, a low minimum K0value and/or a minimum K2value translates to more frequent channel scheduling. Therefore, the base station may transmit the low minimum K0value and/or the minimum K2value to the UE to inform that a delay sensitive DL data will be transmitted, implicitly instructing the UE to switch to the PDCCH monitoring group and monitor the search spaces associated with the PDCCH monitoring group. Furthermore, based on the minimum K0value and/or the minimum K2value, the base station may use at least one bit in the DCI to explicitly indicate the PDCCH monitoring group switching

FIG.5is a diagram500illustrating an example DL channel of the present disclosure. The example DL channel500may include a Group0 and a Group1. The Group0 may include the search space A502and the search space A504, which have a longer periodicity. The Group1 may include the search spaces B506and B508, which have a shorter periodicity. The DCI may include a bit I to indicate the minimum K0value. For example, I=0 may indicate a small minimum K0 value, and I=1 may indicate a large minimum K0 value. The UE may, upon receiving the DCI with the I=0 value determine that the UE should be in group 1, The UE may, upon receiving the DCI value of 1=1, (indicating a larger minimum K0 value), determine that the UE should be in group 0.

Particularly, in the first search space A502, the UE may receive the DCI with the I=1, indicating that the UE may stay in the search space A corresponding to the Group0. In the following second search space A504, the UE may receive the DCI with the I=0, indicating that the UE may switch to the search space B corresponding to the Group1. Accordingly, the UE may switch to monitoring the search space B506corresponding to the Group1. In the third search space B508, the UE may receive the DCI with the I=0, indicating that the UE may stay in the search space B corresponding to the Group1. In the fifth search space B510, the UE may receive the DCI with the I=1, indicating that the UE may switch to the search space A corresponding to the Group0. Accordingly, the UE may timely switch to monitoring the search space A512corresponding to the Group0.

FIG.6is a call flow diagram600of the wireless communication.

At606, the base station604may transmit a configuration for multiple PDCCH monitoring groups. That is, the base station604may transmit the configuration for a plurality of PDCCH monitoring groups to the UE602to monitor different sets of search spaces. For example, the PDCCH monitoring groups may include a first PDCCH monitoring group with a first number of PDCCH monitoring occasions, and a second PDCCH monitoring group with a second number of PDCCH monitoring occasions different from the first number of PDCCH monitoring occasions. The configuration for the multiple PDCCH monitoring groups may be sent via an RRC message.

At608, the base station604may determine the search spaces corresponding to one of the PDCCH monitoring groups used to transmit the PDCCH to the UE602. For example, when the multiple of PDCCH monitoring groups include the first PDCCH monitoring group and the second PDCCH monitoring group, the base station604may determine whether to transmit the PDCCH to the UE in the search spaces corresponding to the first PDCCH monitoring group or the second PDCCH monitoring group.

At612, the UE602may determine to monitor the search spaces corresponding to one of the PDCCH monitoring groups used to receive the PDCCH transmitted from the base station604. For example, when the multiple PDCCH monitoring groups include the first PDCCH monitoring group and the second PDCCH monitoring group, the UE602may determine whether to monitor the search spaces corresponding to the first PDCCH monitoring group or the second PDCCH monitoring group to detect and receive the PDCCH.

At616, the base station604may transmit the PDCCH to the UE602in the search spaces corresponding to the determined one of the multiple PDCCH monitoring groups. For example, when the multiple PDCCH monitoring groups include the first PDCCH monitoring group and the second PDCCH monitoring group, the base station604may transmit the PDCCH in the first PDCCH monitoring group or the second PDCCH monitoring group based on the determination of the search spaces corresponding to one of the PDCCH monitoring group to transmit the PDCCH to the UE602in the first PDCCH monitoring group or the second PDCCH monitoring group in608.

At618, the UE602may monitor the search space associated with the PDCCH monitoring group received from the base station604to receive the PDCCH from the base station604. For example, when the multiple PDCCH monitoring groups include the first PDCCH monitoring group and the second PDCCH monitoring group, the UE602may monitor the search spaces corresponding to the one of the PDCCH monitoring groups that the base station604transmitted the PDCCH to the UE602. That is, the UE monitors the first PDCCH monitoring group or the second PDCCH monitoring group in616based on the determination of the search spaces corresponding to one of the PDCCH monitoring group.

At610, the base station604may transmit an indication to UE602to trigger the dynamic switching of the PDCCH monitoring groups. The indication from the base station604to the UE602may help avoid or reduce a mismatch in the PDCCH monitoring group between the base station604and the UE602.

At614, the UE602may send a request to change the PDCCH monitoring group to the base station604. That is, the UE602may send a request to the base station604to switch the PDCCH monitoring group. For example, when the UE knows that there is an urgent traffic coming, the UE may determine to switch to the PDCCH monitoring group with a shorter periodicity and with more PDCCH monitoring occasions.

FIG.7is a flowchart700of a method of wireless communication. The method may be performed by a UE (e.g., the UE104; the apparatus902). At702, the UE may receive a configuration having multiple PDCCH monitoring groups from a base station (606). For example,702may be performed by a PDCCH monitoring group managing Component940.

At704, the UE may receive an indication of the PDCCH monitoring group from the base station (610). For example,704may be performed by the PDCCH monitoring group managing Component940.

At706, the UE may determine to monitor the search spaces associated with the indicated PDCCH monitoring group (612). For example,706may be performed by the PDCCH monitoring group managing Component940.

At708, the UE may transmit a request to change the PDCCH monitoring group to the base station (614). For example,708may be performed by the PDCCH monitoring group managing Component940.

Finally, at710, the UE may monitor the search spaces corresponding to the PDCCH monitoring group (618). For example,706may be performed by a search space monitoring Component942.

FIG.8is a flowchart800of a method of wireless communication. The method may be performed by a base station (e.g., the base station102/180; the apparatus802. At802, the base station may transmit a configuration for multiple PDCCH monitoring groups to the UE (606). For example,802may be performed by a PDCCH monitoring group managing Component1040.

At804, the base station may determine the search spaces of the PDCCH monitoring group to transmit the PDCCH to the UE (608). For example,804may be performed by the PDCCH monitoring group managing Component1040.

At806, the base station may transmit an indication of the PDCCH monitoring group (610). For example,806may be performed by the PDCCH monitoring group managing Component1040.

At808, the base station may receive a request to change the PDCCH monitoring group from the UE (614). For example,808may be performed by the PDCCH monitoring group managing Component1040.

Finally, at810, the base station may transmit the PDCCH in the PDCCH monitoring group to the UE (616). For example,810may be performed by a PDCCH managing Component1042.

FIG.9is a diagram900illustrating an example of a hardware implementation for an apparatus902. The apparatus902is a UE and includes a cellular baseband processor904(also referred to as a modem) coupled to a cellular RF transceiver922and one or more subscriber identity modules (SIM) cards920, an application processor906coupled to a secure digital (SD) card908and a screen910, a Bluetooth module912, a wireless local area network (WLAN) module914, a Global Positioning System (GPS) module916, and a power supply918. The cellular baseband processor904communicates through the cellular RF transceiver922with the UE104and/or BS102/180. The cellular baseband processor904may include a computer-readable medium/memory. The computer-readable medium/memory may be non-transitory. The cellular baseband processor904is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor904, causes the cellular baseband processor904to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor904when executing software. The cellular baseband processor904further includes a reception component930, a communication manager932, and a transmission component934. The communication manager932includes the one or more illustrated components. The components within the communication manager932may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor904. The cellular baseband processor904may be a component of the UE350and may include the memory360and/or at least one of the TX processor368, the RX processor356, and the controller/processor359. In one configuration, the apparatus902may be a modem chip and include just the baseband processor904, and in another configuration, the apparatus902may be the entire UE (e.g., see350ofFIG.3) and include the aforediscussed additional modules of the apparatus902.

The communication manager932includes a PDCCH monitoring group managing Component940that is configured to receive a configuration for multiple PDCCH monitoring groups from a base station, receive an indication of the PDCCH monitoring group from the base station, determine to monitor the search spaces associated with the PDCCH monitoring group, or transmit a request to change the PDCCH monitoring group to the base station, e.g., as described in connection with702,704,706, or708. The communication manager932further includes a search space monitoring Component942that is configured to monitor the search spaces corresponding to the PDCCH monitoring group to receive the PDCCH, e.g., as described in connection with710. The components940and942may be configured to communicate with each other.

In one configuration, the apparatus902, and in particular the cellular baseband processor904, includes means for receiving the configuration for the PDCCH monitoring groups for monitoring different sets of search spaces from the base station, means for determining whether to monitor the search spaces corresponding to the first PDCCH monitoring group or the second PDCCH monitoring group, means for monitoring the search spaces corresponding to one of the first PDCCH monitoring group or the second PDCCH monitoring group based on the determination to monitor the first PDCCH monitoring group or the second PDCCH monitoring group, means for receiving an indication from the base station indicating to the UE whether to monitor the first PDCCH monitoring group or the second PDCCH monitoring group, and means for transmitting the request to the base station indicating the request to change to monitoring one of the first PDCCH monitoring group or the second PDCCH monitoring group. The aforementioned means may be one or more of the aforementioned components of the apparatus902configured to perform the functions recited by the aforementioned means. As described supra, the apparatus902may include the TX Processor368, the RX Processor356, and the controller/processor359. As such, in one configuration, the aforementioned means may be the TX Processor368, the RX Processor356, and the controller/processor359configured to perform the functions recited by the aforementioned means.

FIG.10is a diagram1000illustrating an example of a hardware implementation for an apparatus1002. The apparatus1002is a BS and includes a baseband unit1004. The baseband unit1004may communicate through a cellular RF transceiver with the UE104. The baseband unit1004may include a computer-readable medium/memory. The baseband unit1004is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the baseband unit1004, causes the baseband unit1004to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the baseband unit1004when executing software. The baseband unit1004further includes a reception component1030, a communication manager1032, and a transmission component1034. The communication manager1032includes the one or more illustrated components. The components within the communication manager1032may be stored in the computer-readable medium/memory and/or configured as hardware within the baseband unit1004. The baseband unit1004may be a component of the BS310and may include the memory376and/or at least one of the TX processor316, the RX processor370, and the controller/processor375.

The communication manager1032includes a PDCCH monitoring group managing Component1040that is configured to transmit a configuration for multiple PDCCH monitoring groups to the UE, determine the search spaces of the PDCCH monitoring group to transmit the PDCCH to the UE, transmit an indication of the PDCCH monitoring group, and receive a request to change the PDCCH monitoring group from the UE, e.g., as described in connection with802,804,806, and808. The communication manager1032further includes a PDCCH managing Component1042that is configured to transmit the PDCCH in the PDCCH monitoring group to the UE, e.g., as described in connection with810. The components1040and1042may be configured to communicate with each other.

In one configuration, the apparatus1002, and in particular the baseband unit1004, includes means for transmitting the configuration for the plurality of PDCCH monitoring groups for monitoring different sets of search spaces to the UE, means for determining whether to transmit the PDCCH to the UE in the search spaces corresponding to the first PDCCH monitoring group or the second PDCCH monitoring group, means for transmitting the PDCCH to the UE in the search spaces corresponding to one of the first PDCCH monitoring group or the second PDCCH monitoring group based on the determination to transmit the PDCCH in the first PDCCH monitoring group or the second PDCCH monitoring group, means for transmitting an indication to the UE indicating to the UE whether to monitor the first PDCCH monitoring group or the second PDCCH monitoring group, means for receiving the request from the UE indicating the request to change to transmitting the PDCCH in one of the first PDCCH monitoring group or the second PDCCH monitoring group. The aforementioned means may be one or more of the aforementioned components of the apparatus1002configured to perform the functions recited by the aforementioned means. As described supra, the apparatus1002may include the TX Processor316, the RX Processor370, and the controller/processor375. As such, in one configuration, the aforementioned means may be the TX Processor316, the RX Processor370, and the controller/processor375configured to perform the functions recited by the aforementioned means.

The apparatus may be a user equipment (UE) and a base station. The base station may transmit, to the UE, a configuration for a plurality of PDCCH monitoring groups for monitoring different sets of search spaces. The PDCCH monitoring groups may include a first PDCCH monitoring group with a first number of PDCCH monitoring occasions and a second PDCCH monitoring group with a second number of PDCCH monitoring occasions different from the first number. The base station may determine which PDCCH monitoring group to send a PHCCH, and transmit the PDCCH to the UE. The UE may determine to monitor search spaces of the PDCCH monitoring group, and monitor search spaces corresponding to the PDCCH monitoring group. The UE may switch between the first and second PDCCH monitoring groups based on a condition or an indication from the base station. The condition may include at least one of an amount of communication traffic, an expected amount of communication traffic, a characteristic of the communication traffic, temperature, time, or light detection. The indication from the base station may be received in a downlink control information (DCI) or implicitly through one of a minimum K0or a minimum K2value. The UE may transmit the request to change the PDCCH monitoring group to monitor to the base station. By dynamically switching the PDCCH monitoring group in the event-based manner may improve the communication performance of the UE and the base station.

Further disclosure is included in the Appendix.