Patent Description:
"<NPL>)" specifies and establishes the characteristics of the physical layer procedures for control operations in <NUM>-NR. "<NPL> documents identified NR enhancements and corresponding evaluations for a single global solution framework for NR based access to unlicensed spectrum. <CIT> relates to systems, apparatuses, and methods for performing and indicating various RA procedures.

Random access is performed by a terminal device, e.g., User Equipment (UE), in a wireless communication network, e.g. a New Radio (NR) or Long Term Evolution (LTE) network for accessing to a new cell. Once a random access procedure is completed, the terminal device can be connected to a network node, e.g. a base station, such as an evolved NodeB (eNB) or gNB, and communicate with the network node using dedicated transmissions.

<FIG> is a diagram illustrating a four-step random access procedure for random access in a wireless communication system, such as an NR system. As shown, the terminal device, such as a user equipment (UE) detects a synchronization signal (SS), including primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH) and decodes Master Information Block (MIB) and System Information Block (SIB) (e.g., Remaining Minimum System Information (RMSI) and Other System Information (OSI), which may be distributed over multiple physical channels such as PBCH and Physical Downlink Shared Channel (PDSCH), to acquire random access transmission parameters.

In step <NUM>, the UE transmits a physical random access channel (PRACH) preamble (message <NUM>) in uplink to a network node. The network node may be a base station, such as a gNB. In step <NUM>, the base station replies with a random access response (RAR, message <NUM>). In step <NUM>, the UE then transmits a UE identification (message <NUM>) on physical uplink shared channel (PUSCH). In step <NUM>, the UE may receive a contention resolution message (CRM, message <NUM>) from the base station.

Message <NUM> and message <NUM> are transmitted in a physical downlink shared channel, PDSCH, scheduled by a physical downlink control channel, PDCCH.

Before receiving message <NUM> and message <NUM>, the UE needs to monitor the PDCCH in a common search space, based on a predefined configuration.

In order to minimize the number of channel accesses, instead of using the four-step random access procedure, a two-step random access procedure, which will be described below with reference to <FIG>, can complete random access in only two steps with two messages, which may be referred to as Message A and Message B. However, for such <NUM>-step random access procedure, there is a need for configuration of PDCCH monitoring.

A search space is a set of PDCCH candidates of a given aggregation level monitored by one or several UEs. A UE-specific search space (USS) is monitored by one UE while a common search space (CSS) may be monitored by several UEs. A search space set is a set of search spaces with different aggregation levels but the same other parameters. In section <NUM> of the 3rd generation partnership project (3GPP) Technical Specification <NUM> v15. <NUM>, a UE procedure for determining PDCCH assignment is described. In particular, a set of PDCCH candidates for a UE to monitor is defined in terms of PDCCH search space sets. A search space set can be a CSS set or a USS set. A UE monitors PDCCH candidates in one or more of the following search spaces sets:.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. There are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

A first aspect of the present disclosure provides a method performed by a terminal device. The method performed by the terminal device comprises obtaining a first configuration indicating Type <NUM> common search space, C-SS, for a first physical downlink control channel, PDCCH and transmitting a message A for requesting a random access, RA. The method also comprises monitoring the first PDCCH based on the Type <NUM> C-SS and receiving a message B on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during the monitoring. The message A includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. The method also comprises obtaining a second different configuration for a second physical downlink control channel, PDCCH and monitoring the second PDCCH, based on the second different configuration. The method also comprises receiving a random access response, RAR on a physical downlink shared channel, PDSCH, based on information in the second PDCCH, when the first PDCCH is not obtained and the second PDCCH is obtained during the monitoring. The RAR is for a four-step random access procedure.

In an embodiment of the present disclosure, the first configuration for the first PDCCH may further comprise a sub-configuration for a control resource set, CORESET.

In an embodiment of the present disclosure, the first configuration for the first PDCCH may be obtained based on a signalling from a network node.

In an embodiment of the present disclosure, the signalling may comprise at least one of: a master information block, MIB; a system information block type1, SIB <NUM>; and a dedicated, radio resource control, RRC, signalling.

A second aspect of the present disclosure provides a method performed by a network node. The method performed by the network node comprises receiving a message A for requesting a random access, RA and transmitting a first physical downlink control channel, PDCCH, based on a first configuration for the first PDCCH, the first configuration indicating Type <NUM> common search space, C-SS. The method also comprises transmitting a message B on a physical downlink shared channel, PDSCH, based on information in the first PDCCH. The message A includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. The method further comprises transmitting a second PDCCH, based on a second different configuration for the second PDCCH and transmitting a random access response, RAR, on a physical downlink shared channel, PDSCH, based on information in the second PDCCH. The RAR is for a four-step random access procedure.

In an embodiment of the present disclosure, the method may further comprise transmitting a signalling including the first configuration for the first PDCCH.

A third aspect of the present disclosure provides a terminal device. The terminal device comprises: a processor and a memory. The memory contains instructions executable by the processor, whereby the terminal device is operative to: obtain a first configuration indicating Type <NUM> common search space, C-SS, for a first physical downlink control channel, PDCCH; transmit a message A for requesting a random access, RA; monitor the first PDCCH, based on the Type <NUM> C-SS; and receive a message B on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during monitoring; obtain a second different configuration for a second physical downlink control channel, PDCCH, monitor the second PDCCH, based on the second different configuration; and receive a random access response, RAR on a physical downlink shared channel, PDSCH, based on information in the second PDCCH, when the first PDCCH is not obtained and the second PDCCH is obtained during the monitoring. The message A includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. The RAR is for a four-step random access procedure.

In an embodiment of the present disclosure, the terminal device may be operative to perform any of the methods described above.

A fourth aspect of the present disclosure provides a network node. The network node comprises a processor and a memory. The memory contains instructions executable by the processor, whereby the network node is operative to: receive a message A for requesting a random access, RA; transmit a first physical downlink control channel, PDCCH, based on a first configuration for the first PDCCH, the first configuration indicating Type <NUM> common search space, C-SS; transmit a message B on a physical downlink shared channel, PDSCH, based on information in the first PDCCH; transmit a second PDCCH, based on a second different configuration for the second PDCCH; transmit a random access response, RAR, on a physical downlink shared channel, PDSCH, based on information in the second PDCCH. The RAR is for a four-step random access procedure. The message A includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH.

In an embodiment of the present disclosure, the network node may be operative to perform any of the methods described above.

A fifth aspect of the present disclosure provides computer readable storage medium. The computer readable storage medium comprises instructions which when executed by a processor of the terminal device of the third aspect, cause the processor to perform a method according to any of the methods of the first aspect, and which when executed by a processor of the network node of the fourth aspect, cause the processor to perform a method according to any of the methods of the second aspect.

According to embodiments of the present disclosure, a terminal device can obtain the configuration of PDCCH monitoring, and then monitor a PDCCH based on the configuration in the <NUM>-step RACH procedure. Therefore, the monitoring of the PDCCH may be achieved in a RACH procedure different from <NUM>-step RACH procedure, such as in a <NUM>-step RACH procedure.

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein the same reference generally refers to the same components in the embodiments of the present disclosure.

As used herein, the term "network", or "communication network/system" refers to a network/system following any suitable communication standards, such as new radio (NR), long term evolution (LTE), LTE-Advanced, wideband code division multiple access (WCDMA), high-speed packet access (HSPA), and so on. Furthermore, the communications between a terminal device and a network node in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (<NUM>), the second generation (<NUM>), <NUM>, <NUM>, the third generation (<NUM>), <NUM>, <NUM>, <NUM> communication protocols, and/or any other protocols either currently known or to be developed in the future.

The term "network node" refers to a network device with accessing function in a communication network via which a terminal device accesses to the network and receives services therefrom. The network node may include a base station (BS), an access point (AP), a multi-cell/multicast coordination entity (MCE), a controller or any other suitable device in a wireless communication network. The BS may be, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a next generation NodeB (gNodeB or gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth.

Yet further examples of the network node comprise multi-standard radio (MSR) radio equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, positioning nodes and/or the like. More generally, however, the network node may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a terminal device access to a wireless communication network or to provide some service to a terminal device that has accessed to the wireless communication network.

The term "terminal device" refers to any end device that can access a communication network and receive services therefrom. By way of example and not limitation, the terminal device may refer to a user equipment (UE), or other suitable devices. The UE may be, for example, a subscriber station, a portable subscriber station, a mobile station (MS) or an access terminal (AT). The terminal device may include, but not limited to, portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA), a vehicle, and the like.

As yet another specific example, in an Internet of things (IoT) scenario, a terminal device may also be called an IoT device and represent a machine or other device that performs monitoring, sensing and/or measurements etc., and transmits the results of such monitoring, sensing and/or measurements etc. to another terminal device and/or a network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3rd generation partnership project (3GPP) context be referred to as a machine-type communication (MTC) device.

As one particular example, the terminal device may be a UE implementing the 3GPP narrow band Internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may represent a vehicle or other equipment, for example, a medical instrument that is capable of monitoring, sensing and/or reporting etc. on its operational status or other functions associated with its operation.

A <NUM>-step RACH work item has been approved in RANI #<NUM> plenary meeting where the initial access is completed in only two steps as illustrated in <FIG>. Here, the first operation of detecting SSB and system information is the same as in the <NUM>-step approach but then follows by only two steps in order to minimize the number of channel accesses, which is important for e.g. operation in unlicensed frequency bands where listen before talk must be performed before transmission.

At the first step, the UE transmits, to the base station e.g. gNB, a request message (which may be denoted as message A, MsgA) for the random access. The request message (or MsgA) comprises a RACH preamble and a PUSCH. At the second step, the UE receives, from the base station, a response (which may be denoted as message B, MsgB).

In more particular, the request message or message A (msgA) may include random access preamble together with higher layer data such as radio resource control (RRC) connection request possibly with some small payload on PUSCH. At the second step, the gNB transmits or the UE receives a random access response (RAR) (or MsgB) e.g. including UE identifier assignment, timing advance information, and contention resolution message, etc..

When introducing the <NUM>-step random access procedure, the PUSCH in MsgA is transmitted at the same time instance as the preamble, after which MsgB can be transmitted in a PDSCH scheduled by PDCCH within a control-resource set (CORESET) and a search space to be monitored by UE. Which CORESET and the search space to be used should be configured/determined in this case.

<FIG> is an exemplary flow chart showing methods for monitoring PDCCH in a random access procedure, e.g. <NUM>-step random access procedure, according to an embodiment of the present disclosure.

As shown in <FIG>, a method is performed by a terminal device. The method includes: step S101, obtaining a first configuration for a first physical downlink control channel, PDCCH; step S102, transmitting a message for requesting a random access, RA; step S <NUM>, monitoring the first PDCCH, based on the first configuration; and step S <NUM>, receiving a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during the monitoring. The message for requesting the RA includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH may be a response to the message for requesting the RA.

According to an embodiment of the present disclosure, the method is performed by a terminal device to obtain the configuration of PDCCH monitoring, and then to monitor a PDCCH based on the configuration in the <NUM>-step RACH procedure.

<FIG> also shows a corresponding method performed by a network node. The method includes: S201, receiving a message for requesting a random access, RA from a UE; S202, transmitting a first physical downlink control channel, PDCCH, based on a first configuration for the first PDCCH; S203, transmitting a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH. The message for requesting the RA includes: a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH is a response to the message for requesting the RA.

According to an embodiment of the present disclosure, the method is performed by a network node, allowing a terminal device to obtain the configuration of PDCCH monitoring, and then to monitor a PDCCH from the network node based on the configuration in the <NUM>-step RACH procedure.

In an embodiment of the present disclosure, the first configuration for the first PDCCH comprises at least one of: a first sub-configuration for a control resource set, CORESET; or a second sub-configuration for a common search space, C-SS.

In an embodiment of the present disclosure, the first configuration for the first PDCCH is obtained, based on a second configuration for a second PDCCH used for a random access response, RAR, as used in a four-step random access procedure.

A CORESET consists of a number of resource blocks in the frequency domain and a number of orthogonal frequency division multiplexing, OFDM, symbols in the time domain wherein a UE monitors a physical downlink control channel (PDCCH).

Each PDCCH consists of one or more control-channel elements (CCEs). A control-channel element (CCE) consists of <NUM> resource-element groups (REGs) where a resource-element group equals one resource block during one OFDM symbol. Resource-element groups within a control-resource set are numbered in increasing order in a time-first manner, starting with <NUM> for the first OFDM symbol and the lowest-numbered resource block in the control resource set.

A UE can be configured with multiple control-resource sets.

For example, the CORESET and/or the C-SS may have the same definition as in the four-step RA procedure. Specifically, the CORESET configurations for RACH procedure and C-SS (e.g. type <NUM>) can be found in the IE PDCCH-ConfigCommon from the 3rd generation partnership project technical specification (3GPP TS) <NUM> V15. The example structure of the IE PDCCH-ConfigCommon is shown below, and the corresponding part to CORESET and C-SS for random access are emphasized with underlines.

<FIG> is an exemplary flow chart showing a substep of the methods in <FIG>, according to embodiments of the present disclosure.

As shown in <FIG>, the method performed at the network node further comprises: S204, transmitting a signalling including the first configuration for the first PDCCH.

Accordingly, in embodiments of the present disclosure, the first configuration for the first PDCCH may be obtained by the terminal device, based on a signalling from a network node.

In embodiments of the present disclosure, the signalling comprises at least one of: a master information block, MIB; a system information block type1, SIB <NUM>; and a dedicated, radio resource control, RRC, signalling.

As one example, when a first configuration for the first PDCCH in two-step RA is obtained, based on a second configuration for a second PDCCH used for a RAR in a four-step random access procedure, the signalling may be one for the RAR in a four-step RA. This is, the CORESET configuration(s) for msgB can be the same as configured in system information block type <NUM>, SIB1, or in dedicated RRC signalling for <NUM>-step RA. Further, the C-SS configuration (s) for msgB can be the same as configured in system information block type <NUM>, SIB <NUM>, or in dedicated RRC signalling for <NUM>-step RA.

Therefore, according to embodiments of the present disclosure, existing configurations may be reused, to reduce the overhead of the signalling on the CORESET and/or the search space for msgB. Thus, the communication resource, such as radio resource will be saved.

As other examples, there may be new specified IEs, or even a new specified signalling for the first configuration for the first PDCCH in two-step RA, besides the existing IEs and signalling for the four-step RA, so as to increase the flexibility of the configurations.

Such other examples will provide more flexibility to configure a CORSET and/or the search space specifically for the msgB in <NUM>-step RA. New search space definitions can further reduce the delay between msgA and msgB, and thus reduce the time needed for the whole random access.

The CORSET and/or the C-SS can be separately defined. For example, new Search Space IE, which is underlined below, maybe further defined. <IMG>
<IMG>.

This is, a UE is configured with a search space for PDCCH carrying msgB (a `<NUM>-step RA search space'). In such embodiments, the UE is configured with a RACH occasion before monitoring the <NUM>-step RA search space. The UE transmits a RACH preamble during the RACH occasion, and then monitors the search space for the PDCCH scheduling msgB. It may be advantageous for UEs to transmit RACH preambles used for either <NUM>-step or <NUM>-step random access in the RACH occasion. Since a PUSCH carrying msgA is transmitted after the corresponding RACH preamble, and since some time is needed to receive msgA as well as to determine the corresponding content of msgB, the delay from RACH preamble to msgB transmission is generally different from the delay from RACH preamble to message <NUM>. Consequently, the use of a search space for PDCCH scheduling msgB that is distinct from a search space for PDCCH scheduling message <NUM> can allow more optimal timing for msgB.

In embodiments of the present disclosure, the network node comprises: a base station. Namely, a base station may transmit signalling including above configurations to a terminal device.

In embodiments of the present disclosure, the first sub-configuration for the CORESET has a default value configured in a master information block, MIB; and/or the second sub-configuration for the C-SS has a default value configured in a master information block, MIB.

In embodiments of the present disclosure, the default value of the first sub-configuration for the CORESET is CORESET <NUM>; and/or the default value of the second sub-configuration for the C-SS is Type <NUM>. Type <NUM> C-SS is a C-SS in Type <NUM> C-SS set as defined in section <NUM> of 3GPP TS <NUM> v15.

For example, if the CORESET and/or the C-SS is not configured yet, (e.g. no dedicated signalling for such configuration is received, and/or there is no configuration in SIB1), then, CORESET <NUM> is used as the default CORESET for two-step RACH procedure, and/or TypeO C-SS is used as the default search space for two-step RACH procedure. CORESET <NUM> and TypeO C-SS may be configured in MIB. In embodiments of the present disclosure, the second sub-configuration for the C-SS has a fixed value.

In embodiments of the present disclosure, the fixed value of the second sub-configuration for the C-SS is Type <NUM>. Type <NUM> C-SS is a C-SS in Type <NUM> C-SS set as defined in section <NUM> of 3GPP TS <NUM> v15.

According to embodiments of the present disclosure, the C-SS may have a fixed value, so as to simplify the procedure. Namely, no extra IE or signalling will be needed. Further, when selecting the fixed value, generality and practicability may be focused. A Type <NUM> C-SS may be selected, since this Type <NUM> C-SS should be commonly used in structure of new radio-release <NUM>, NR-R15, and Type <NUM> C-SS may reduce a delay between msgA and msgB in a two-step RA.

As an exemplary comparison, if TypeO C-SS is used as the default C-SS for msgB, then, the delay between msgA and the start of the msgB window can be up to <NUM> (when SSB, and CORESETO are multiplexed in a time division multiplexing, TDM, manner) and up to the SSB periodicity (when the SSB and CORESETO are multiplexed in a frequency division multiplexing, FDM, manner). While with the type <NUM> C-SS, the delay between msgA and msgB can be <NUM> slot in minimum. SSB refers to SS/PBCH blocks described in 3GPP TS <NUM>, wherein SS/PBCH refers to Synchronization Signal / Physical Broadcast Physical Channel.

In embodiments of the present disclosure, a first sub-configuration for the CORESET includes a first modification to a CORESET <NUM>, and/or a second sub-configuration for the C-SS includes a second modification to a C-SS Type <NUM>.

In embodiments of the present disclosure, at least one of the first modification or the second modification is used to increase a frequency of monitoring the PDCCH.

In embodiments of the present disclosure, the second modification to a C-SS Type <NUM> is related to a parameter for monitoring periodicity and monitoring timing offset.

This parameter may be "monitoringSlotPeriodicityAndOffset" shown in below. <IMG>
<IMG>.

The separate COREST and/or SS for two-step RA can be determined via modifying the existing CORESETs or search spaces for four-step RA. For example, more monitoring occasions in search space <NUM>, SS0, with CORESETO when a type0 C-SS is used to reduce the gap between msgA and msgB. A monitoring periodicity of the modified search space for RACH procedure is every slot (or a period no larger than a predetermined value) instead of every <NUM> slots.

If the total number of monitoring occasions for the reception of system information (e.g., RMSI) is indicated as one in a slot in PBCH, the terminal device (e.g. UE) may monitor the same search space symbols as RMSI. If more than one CORESET monitoring occasions exist in one slot, a predetermined one of the CORESET monitoring occasions can be used for <NUM>-step RA, or the actual COERSET monitoring occasion(s) to be monitored in this slot can be signaled in RRC signaling, or it can be indicated by other known one or more parameters: the CORESET configuration, the msgA preamble configurations, System Frame Number, SFN, etc..

<FIG> is an exemplary flow chart showing substeps of the methods in <FIG>, according to embodiments of the present disclosure.

In embodiments of the present disclosure, the method performed by the terminal device <NUM> further comprises: S105, obtaining a second different configuration for a second physical downlink control channel, PDCCH; S106, monitoring the second PDCCH, based on the second different configuration; and S107, receiving a random access response, RAR on a physical downlink shared channel, PDSCH, based on information in the second PDCCH, when the first PDCCH is not obtained and the second PDCCH is obtained during the monitoring. The RAR is for a four-step random access procedure.

Further, in embodiments of the present disclosure, the method performed by the network node <NUM> further comprises: S205, transmitting a second PDCCH, based on a second different configuration for the second PDCCH; and S206, transmitting a random access response, RAR, on a physical downlink shared channel, PDSCH, based on information in the second PDCCH. The RAR is for a four-step random access procedure.

According to embodiments of the present disclosure, the UE is additionally configured with a search space used for reception of PDCCH scheduling message <NUM> (the `RA Search Space') in <NUM> step random access, along with the `<NUM>-step RA search space'. In these embodiments, if the UE detects a PDCCH scheduling msgB in the corresponding search space, it determines that a <NUM>-step RACH msgA attempt was received by the base station, such as gNB, and then the UE ignores the (<NUM>-step) RA search space, and continues with <NUM> step RACH access. If a PDCCH scheduling msgB is not detected in the <NUM>-step RA search space, but a PDCCH scheduling message <NUM> is detected in the (<NUM>-step) RA search space, the UE determines that the <NUM> step RACH attempt was not successful, but it should proceed with a <NUM> step random access including processing message <NUM>. A fallback mechanism between two step RA and four-step RA is further supported by using different configurations.

<FIG> is a block diagram showing the terminal device and the network node in accordance with embodiments of the present disclosure.

As shown in <FIG>, the terminal device <NUM> comprises: a processor <NUM>; and a memory <NUM>. The memory <NUM> contains instructions executable by the processor <NUM>. The terminal device <NUM> is operative to: obtain (S101) a first configuration for a first physical downlink control channel, PDCCH; transmit (S102) a message for requesting a random access, RA; monitor (S103) the first PDCCH, based on the first configuration; and receive (S104) a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during monitoring. The message for requesting the RA includes: a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH is a response to the message for requesting the RA.

In embodiments of the present disclosure, the terminal device is further operative to perform any method above mentioned. For example, the terminal device is further operative to: obtain (S105) a second different configuration for a second PDCCH; monitor (S106) the second PDCCH, based on the second different configuration; and receive (S107) a RAR on a PDSCH, based on information in the second PDCCH, if the first PDCCH is not obtained and the second PDCCH is obtained during monitoring.

As shown in <FIG>, the network node <NUM> comprises: a processor <NUM>; and a memory <NUM>. The memory <NUM> contains instructions executable by the processor <NUM>. The network node <NUM> is operative to: receive (S201) a message for requesting a random access, RA; transmit (S202) a first physical downlink control channel, PDCCH, based on a first configuration for the first PDCCH; transmit (S203) a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH. The message for requesting the RA includes: a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH is a response to the message for requesting the RA.

In embodiments of the present disclosure, the network node <NUM> is further operative to perform any method above mentioned. For example, the network node <NUM> is further operative to transmit (S204) a signalling including the first configuration for the first PDCCH. The network node <NUM> is further operative to transmit (S205) a second PDCCH, based on a second different configuration for the second PDCCH; and transmit (S206) a random access response, RAR, on a physical downlink shared channel, PDSCH, based on information in the second PDCCH. The RAR is for a four-step random access procedure.

The processors <NUM>, <NUM> may be any kind of processing component, such as one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The memories <NUM>, <NUM> may be any kind of storage component, such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc..

<FIG> is a block diagram showing a computer readable storage medium in accordance with embodiments of the present disclosure.

As shown in <FIG>, the computer readable storage medium <NUM> comprising instructions/program <NUM> which when executed by a processor, cause the processor to perform any above mentioned method.

The computer readable storage medium <NUM> may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, or flash drives.

According to embodiments of the present disclosure, the monitoring of the PDCCH may be achieved in a RACH procedure different with <NUM>-step RACH procedure, such as in a <NUM>-step RACH procedure.

<FIG> is a schematic showing function units of the terminal device. As shown in <FIG>, the terminal device <NUM> may comprise: an obtaining unit <NUM>, configured to obtain (S101) a first configuration for a first physical downlink control channel, PDCCH; a transmitting unit <NUM>, configured to transmit (S102) a message for requesting a random access, RA; a monitoring unit <NUM>, configured to monitor (S103) the first PDCCH, based on the first configuration; and a receiving unit <NUM>, configured to receive (S <NUM>) a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during monitoring. The message for requesting the RA includes: a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH is a response to the message for requesting the RA.

Further, the obtaining unit <NUM> is further configured to obtain (S105) a second different configuration for a second PDCCH. The monitoring unit <NUM> is further configured to monitor (S <NUM>) the second PDCCH, based on the second different configuration. The receiving unit <NUM> may be further configured to receive (S107) a RAR on a PDSCH, based on information in the second PDCCH, if the first PDCCH is not obtained and the second PDCCH is obtained during monitoring.

<FIG> is a schematic showing function units of the network node. As shown in <FIG>, the network node <NUM> may comprise: a receiving unit <NUM>, configured to receive (S201) a message for requesting a random access, RA; a transmitting unit <NUM>, configured to transmit (S202) a first physical downlink control channel, PDCCH, based on a first configuration for the first PDCCH; and transmit (S203) a message on a physical downlink shared channel, PDSCH, based on information in the first PDCCH. The message for requesting the RA includes: a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH. Further, the message on the PDSCH is a response to the message for requesting the RA.

The transmitting unit <NUM> may be further configured to transmit (S204) a signalling including the first configuration for the first PDCCH. The transmitting unit <NUM> is further configured to transmit (S205) a second PDCCH, based on a second different configuration for the second PDCCH; and transmit (S206) a random access response, RAR, on a physical downlink shared channel, PDSCH, based on information in the second PDCCH. The RAR is for a four-step random access procedure.

With function units, the terminal device or network node may not need a fixed processor or memory, any computing resource and storage resource may be arranged from at least one network node, or terminal device in the communication system. The introduction of virtualization technology and network computing technology may improve the usage efficiency of the network resources and the flexibility of the network.

Further, the exemplary overall commutation system including the terminal device and the network node will be introduced as below.

Embodiments of the present disclosure provide a communication system including a host computer including: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a terminal device. The cellular network includes a network node above mentioned, and/or the terminal device is above mentioned.

In embodiments of the present disclosure, the system further includes the terminal device, wherein the terminal device is configured to communicate with the network node.

In embodiments of the present disclosure, the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the terminal device includes processing circuitry configured to execute a client application associated with the host application.

Embodiments of the present disclosure also provide a communication system including a host computer including: a communication interface configured to receive user data originating from a transmission from a terminal device; a network node. The transmission is from the terminal device to the network node. The network node is above mentioned, and/or the terminal device is above mentioned.

In embodiments of the present disclosure, the processing circuitry of the host computer is configured to execute a host application. The terminal device is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer.

<FIG> is a schematic showing a wireless network in accordance with some embodiments.

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes (such as a base station) <NUM> and 1060b, and WDs (corresponding to terminal device) <NUM>, 1010b, and 1010c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

As illustrated, interface <NUM> comprises port(s)/terminal(s) <NUM> to transmit and receive data, for example to and from network <NUM> over a wired connection.

Antenna <NUM> may include one or more antennas, or antenna arrays, configured to transmit and/or receive wireless signals.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE), a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

Antenna <NUM> may include one or more antennas or antenna arrays, configured to transmit and/or receive wireless signals, and is connected to interface <NUM>.

<FIG> is a schematic showing a user equipment in accordance with some embodiments.

Network connection interface <NUM> may be configured to provide a communication interface to network 1143a. Network 1143a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1143a may comprise a Wi-Fi network.

Storage medium <NUM> may allow UE <NUM> to access computer-executable instructions, application programs or the like, stored on transitory or non-transitory memory media, to offload data, or to upload data.

In <FIG>, processing circuitry <NUM> may be configured to communicate with network 1143b using communication subsystem <NUM>. Network 1143a and network 1143b may be the same network or networks or different network or networks. Communication subsystem <NUM> may be configured to include one or more transceivers used to communicate with network 1143b.

Network 1143b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1143b may be a cellular network, a Wi-Fi network, and/or a near-field network.

<FIG> is a schematic showing a virtualization environment in accordance with some embodiments.

<FIG> is a schematic showing a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments.

Access network <NUM> comprises a plurality of base stations 1312a, 1312b, 1312c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1313a, 1313b, 1313c. Each base station 1312a, 1312b, 1312c is connectable to core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 1313c is configured to wirelessly connect to, or be paged by, the corresponding base station 1312c. A second UE <NUM> in coverage area 1313a is wirelessly connectable to the corresponding base station 1312a.

<FIG> is a schematic showing a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.

It is noted that host computer <NUM>, base station <NUM> and UE <NUM> illustrated in <FIG> may be similar or identical to host computer <NUM>, one of base stations 1312a, 1312b, 1312c and one of UEs <NUM>, <NUM> of <FIG>, respectively.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the latency, and power consumption for a reactivation of the network connection, and thereby provide benefits, such as reduced user waiting time, enhanced rate control.

According to embodiments of the present disclosure, the monitoring of PDCCH may be achieved in a RACH procedure different with <NUM>-step RACH procedure, such as in a <NUM>-step RACH procedure.

In general, the various exemplary embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto.

It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may include circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by those skilled in the art, the functionality of the program modules may be combined or distributed as desired in various embodiments. In addition, the functionality may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA), and the like.

Claim 1:
A method performed by a terminal device, the method comprising:
obtaining (S101) a first configuration indicating Type <NUM> common search space, C-SS, for a first physical downlink control channel, PDCCH;
transmitting (S102) a message A for requesting a random access, RA, wherein the message A includes a random access channel, RACH, preamble and a physical uplink shared channel, PUSCH;
monitoring (S103) the first PDCCH, based on the Type <NUM> C-SS;
receiving (S104) a message B on a physical downlink shared channel, PDSCH, based on information in the first PDCCH obtained during the monitoring;
obtaining (S105) a second different configuration for a second physical downlink control channel, PDCCH;
monitoring (S106) the second PDCCH, based on the second different configuration; and
receiving (S107) a random access response, RAR on a physical downlink shared channel, PDSCH, based on information in the second PDCCH, when the first PDCCH is not obtained and the second PDCCH is obtained during the monitoring;
wherein the RAR is for a four-step random access procedure.