METHOD, DEVICE, AND SYSTEM FOR DETERMINING TIMING IN WIRELESS NETWORKS

This disclosure relates generally to a method, device, and system for determining timing information for uplink and downlink transmission in a wireless network. One method performed by a wireless device is disclosed. The method may include at least one of: configuring two DL timings for DL transmission from a network element, wherein the two DL timings include a first DL timing and a second DL timing; or configuring two UL timings for UL transmission to the network element, wherein the two UL timings include a first UL timing and a second UL timing; and wherein each of the two DL timings and each of the two UL timings are associated with a time block for the DL transmission or the UL transmission.

TECHNICAL FIELD

This disclosure is directed generally to wireless communications, and particularly to a method, device, and system for determining timing information for uplink and downlink transmission in a wireless network.

BACKGROUND

Flexible and efficient wireless transmission resource scheduling is critical in the wireless communication network. The ecosystem in a wireless communication network includes more and more applications that require low latency. These applications include Vehicle-to-Vehicle Communication, self-driving, mobile gaming, etc. Specifically, when Time Division Multiplex (TDD) is deployed in the wireless network, in order to reduce transmission latency, it is desirable to enable full duplex data/signal transmission for certain slot and/or symbols. Sub-band Full Duplex (SBFD) is an important feature for implementing full duplex in TDD system. Determining timing information is critical in SBFD, for example, to reduce self-interference strength, ease difficulty of self-interference cancellation, reduce Channel State Information (CSI) feedback overhead, and boost system performance.

SUMMARY

This disclosure is directed to a method, device, and system for determining timing information for uplink and downlink transmission in a wireless network, and in particular, in a TDD system deploying the SBFD feature.

In some embodiments, a method performed by a wireless device is disclosed. The method may include at least one of: configuring two downlink (DL) timings for DL transmission from a network element, wherein the two DL timings include a first DL timing and a second DL timing; or configuring two uplink (UL) timings for UL transmission to the network element, wherein the two UL timings include a first UL timing and a second UL timing; and wherein each of the two DL timings and each of the two UL timings are associated with a time block for the DL transmission or the UL transmission.

In some embodiments, the method above may further include: the first UL timing is based on a timing advance value; and the second UL timing is based on the timing advance value and a timing advance offset value.

In some embodiments, the method above may further include: the first DL timing is determined based on a reference signal, the reference signal comprising at least one of: a Synchronization Signal Block (SSB), or a Channel State Information Reference Signal (CSI-RS).

In some embodiments, the method above may further include: the second DL timing is based on the first DL timing, and a timing advance offset value.

In some embodiments, a method performed by a network element is disclosed. The method may include: configuring two UL timings for UL transmission, wherein the two UL timings include a first UL timing and a second UL timing.

In some embodiments, the method above may further include: the second UL timing is based on the first UL timing and a timing advance offset value; or the first UL timing is based on the second UL timing and the timing advance offset value.

In some embodiments, the method above may further include: configuring two DL timings for DL transmission, wherein the two DL timings include a first DL timing and a second DL timing.

In some embodiments, there is a network element or a UE comprising a processor and a memory, wherein the processor is configured to read code from the memory and implement any methods recited in any of the embodiments.

In some embodiments, a computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement any method recited in any of the embodiments.

The above embodiments and other aspects and alternatives of their implementations are described in greater detail in the drawings, the descriptions, and the claims below.

DETAILED DESCRIPTION

Wireless Communication Network

FIG.1shows an exemplary wireless communication network100that includes a core network110and a radio access network (RAN)120. The core network110further includes at least one Mobility Management Entity (MME)112and/or at least one Access and Mobility Management Function (AMF). Other functions that may be included in the core network110are not shown inFIG.1. The RAN120further includes multiple base stations, for example, base stations122and124. The base stations may include at least one evolved NodeB (eNB) for 4G LTE, an enhanced LTE eNB (ng-eNB), or a Next generation NodeB (gNB) for 5G New Radio (NR), or any other type of signal transmitting/receiving device such as a UMTS NodeB. The eNB122communicates with the MME112via an S1interface. Both the eNB122and gNB124may connect to the AMF114via an Ng interface. Each base station manages and supports at least one cell. For example, the base station gNB124may be configured to manage and support cell1, cell2, and cell3.

The gNB124may include a central unit (CU) and at least one distributed unit (DU). The CU and the DU may be co-located in a same location, or they may be split in different locations. The CU and the DU may be connected via an F1interface. Alternatively, for an eNB which is capable of connecting to the 5G network, it may also be similarly divided into a CU and at least one DU, referred to as ng-eNB-CU and ng-eNB-DU, respectively. The ng-eNB-CU and the ng-eNB-DU may be connected via a W1interface.

The wireless communication network100may include one or more tracking areas. A tracking area may include a set of cells managed by at least one base station. For example, tracking area1labeled as140includes cell1, cell2, and cell3, and may further include more cells that may be managed by other base stations and not shown inFIG.1. The wireless communication network100may also include at least one UE160. The UE may select a cell among multiple cells supported by a base station to communication with the base station through Over the Air (OTA) radio communication interfaces and resources, and when the UE160travels in the wireless communication network100, it may reselect a cell for communications. For example, the UE160may initially select cell1to communicate with base station124, and it may then reselect cell2at certain later time point. The cell selection or reselection by the UE160may be based on wireless signal strength/quality in the various cells and other factors.

The wireless communication network100may be implemented as, for example, a 2G, 3G, 4G/LTE, or 5G cellular communication network. Correspondingly, the base stations122and124may be implemented as a 2G base station, a 3G NodeB, an LTE eNB, or a 5G NR gNB. The UE160may be implemented as mobile or fixed communication devices which are capable of accessing the wireless communication network100. The UE160may include but is not limited to mobile phones, laptop computers, tablets, personal digital assistants, wearable devices, Internet of Things (IOT) devices, MTC/eMTC devices, distributed remote sensor devices, roadside assistant equipment, XR devices, and desktop computers. The UE160may also be generally referred to as a wireless communication device, or a wireless terminal. The UE160may support sidelink communication to another UE via a PC5interface.

While the description below focuses on cellular wireless communication systems as shown inFIG.1, the underlying principles are applicable to other types of wireless communication systems for paging wireless devices. These other wireless systems may include but are not limited to Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

FIG.2shows an example of electronic device200to implement a network base station (e.g., a radio access network node), a core network (CN), and/or an operation and maintenance (OAM). Optionally in one implementation, the example electronic device200may include radio transmitting/receiving (Tx/Rx) circuitry208to transmit/receive communication with UEs and/or other base stations. Optionally in one implementation, the electronic device200may also include network interface circuitry209to communicate the base station with other base stations and/or a core network, e.g., optical or wireline interconnects, Ethernet, and/or other data transmission mediums/protocols. The electronic device200may optionally include an input/output (I/O) interface206to communicate with an operator or the like.

The electronic device200may also include system circuitry204. System circuitry204may include processor(s)221and/or memory222. Memory222may include an operating system224, instructions226, and parameters228. Instructions226may be configured for the one or more of the processors221to perform the functions of the network node. The parameters228may include parameters to support execution of the instructions226. For example, parameters may include network protocol settings, bandwidth parameters, radio frequency mapping assignments, and/or other parameters.

FIG.3shows an example of an electronic device to implement a terminal device300(for example, a user equipment (UE)). The UE300may be a mobile device, for example, a smart phone or a mobile communication module disposed in a vehicle. The UE300may include a portion or all of the following: communication interfaces302, a system circuitry304, an input/output interfaces (I/O)306, a display circuitry308, and a storage309. The display circuitry may include a user interface310. The system circuitry304may include any combination of hardware, software, firmware, or other logic/circuitry. The system circuitry304may be implemented, for example, with one or more systems on a chip (SoC), application specific integrated circuits (ASIC), discrete analog and digital circuits, and other circuitry. The system circuitry304may be a part of the implementation of any desired functionality in the UE300. In that regard, the system circuitry304may include logic that facilitates, as examples, decoding and playing music and video, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user inputs; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections for, as one example, internet connectivity; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface310. The user interface310and the inputs/output (I/O) interfaces306may include a graphical user interface, touch sensitive display, haptic feedback or other haptic output, voice or facial recognition inputs, buttons, switches, speakers and other user interface elements. Additional examples of the I/O interfaces306may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input/output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

Referring toFIG.3, the communication interfaces302may include a Radio Frequency (RF) transmit (Tx) and receive (Rx) circuitry316which handles transmission and reception of signals through one or more antennas314. The communication interface302may include one or more transceivers. The transceivers may be wireless transceivers that include modulation/demodulation circuitry, digital to analog converters (DACs), shaping tables, analog to digital converters (ADCs), filters, waveform shapers, filters, pre-amplifiers, power amplifiers and/or other logic for transmitting and receiving through one or more antennas, or (for some devices) through a physical (e.g., wireline) medium. The transmitted and received signals may adhere to any of a diverse array of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and encodings. As one specific example, the communication interfaces302may include transceivers that support transmission and reception under the 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA)+, 4G/Long Term Evolution (LTE), and 5G standards. The techniques described below, however, are applicable to other wireless communications technologies whether arising from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

Referring toFIG.3, the system circuitry304may include one or more processors321and memories322. The memory322stores, for example, an operating system324, instructions326, and parameters328. The processor321is configured to execute the instructions326to carry out desired functionality for the UE300. The parameters328may provide and specify configuration and operating options for the instructions326. The memory322may also store any BT, WiFi, 3G, 4G, 5G or other data that the UE300will send, or has received, through the communication interfaces302. In various implementations, a system power for the UE300may be supplied by a power storage device, such as a battery or a transformer.

Transmission Resource in Wireless Network

In a wireless network, data and/or signal are transmitted using wireless transmission resource. The transmission resource may be presented as a two-dimensional grid with time being one dimension and frequency being the other dimension.

Referring toFIG.4for an exemplary transmission resource configuration in a wireless network, such network may be operated in TDD mode. In the time domain, the transmission resource may be organized by time block, such as slot (or time slot), like slot0to slot4as shown inFIG.4. Based on data/signal transmission direction, a slot may be assigned to a downlink (DL) direction, in which case the slot is dedicated to DL transmission/traffic. A slot may also be assigned to an uplink (UL) direction, in which case the slot the slot is dedicated for UL transmission/traffic. A slot may also be configured as a flexible slot, in the sense that the slot may be configured flexibly to support both DL and UL traffic. Further, the flexible slot may support both DL and UL transmission simultaneously, or, the flexible slot may support DL transmission in one cycle, and support UL transmission another cycle. The direction assigned to a slot may be associated with a format of the slot. For example, a DL format (or D format) slot is dedicated to DL transmission; a UL format (or U format) slot is dedicated to UL transmission; a flexible format (or F format) slot may support bi-directional transmission.

The transmission resource may present periodically. Exemplarily, as shown inFIG.4, the transmission resource402has a “DDDFU” pattern (D: DL slot; F: flexible slot; U: UL slot). The character “D”, “U”, and “F” may each represent a format of a slot. In this example, this particular pattern has a periodicity of 2.5 millisecond (ms).

It should be noted that the aforementioned “DDDFU” pattern and its periodicity are merely for example purpose. Other patterns and associated periodicities may be configured based on a practical requirement. A pattern may be a combination of various number of slots in various formats. For example, an example pattern may be “DDDDFUU”. In this pattern, there are4continuous DL slots, a single flexible slot, and 2 continuous UL slots.

In some embodiment, the format, such as DL, UL, and flexible format may also generally apply to a time block such as a symbol. The symbol may include at least one of:Orthogonal Frequency Division Multiplexing (OFDM) symbol;Single Carrier Frequency Division Multiplexing Access (SC-FDMA) symbol; orFilter Bank Multiple Access (FBMA) symbol.

Using OFDM symbol as an example, each slot may include multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols. Referring toFIG.4, a slot may include 14 OFDM symbols. In the frequency domain, each symbol may include multiple Resource Blocks (RBs). The number of RBs in each OFDM symbol may depend on, for example, the bandwidth of the cell or the carrier.

In a conventional TDD system, there is no specific frequency resource dedicated to downlink or uplink. One frequency resource may be used for downlink transmission, uplink transmission or both downlink and uplink transmission in TDD manner.

In an exemplary wireless network operating in TDD mode, as discussed above, the data/signal transmission (and associated time block) may follow a certain pattern, such as “DDDFU”. The following discussion will be based on this pattern although it will be appreciated that the transmission may follow other various patterns. The discussion will use slot for example purpose, and other time block may apply as well. In the “DDDFU” pattern, slots0-2are DL slots, slot3is flexible slot, whereas slot4is UL slot. The resulting DL and UL traffic is therefore time division duplexed as per the transmission slot pattern. It is overserved that UL transmission has only a single dedicated slot. From a network performance perspective, UL transmission may suffer from excessive latency since the UE is restricted to transmitting in the single dedicated U slot and in the UL resource allocated in the flexible slot. This may lead to performance issue, especially for latency sensitive applications, such as intelligent transport systems, vehicle to vehicle communications, remote surgery, etc. Another factor to consider is that the transmission energy for the UL communication is constrained to the dedicated U slot, and this may lead to sub-optimal or degraded radio coverage.

To address the aforementioned issues with regard to latency and transmission energy limitation, one solution is to introduce a Sub-band Full Duplex (SBFD) mode to the wireless network. Advantage of SBFD may include enhanced signal coverage and reduced communication latency.

SBFD may be implemented in various ways. For example, one possible implementation is via sub-bands. Referring toFIG.5, slots1-2, which are originally dedicated to DL transmission, may be re-configured so that a portion of spectrum resource in slots1-2may be allocated to create a UL sub-band (UL SB502) to support UL transmission, while the rest of spectrum resource still supports DL transmission. Therefore, simultaneous DL and UL transmissions may be achieved in slots1-2. Likewise, slot4, which is originally dedicated to UL transmission, may be re-configured and a portion of spectrum resource (DL SB504) may be allocated to support DL transmission. In this example, slot0remains in original format (D) and it is still dedicated to DL transmission. In some embodiments, a sub-band, such as UL SB502and DL SB504, may be formed by one or more resource blocks.

Another possible implementation of SBFD is via multiple Bandwidth Parts (BWPs). For example, multiple BWPs may be configured and activated simultaneously, and each activated BWP may have its own DL and/or UL configuration, such as pattern and periodicity. With multiple activated BWPs, it is possible that for a given time and for a given UE, one BWP is allocated for DL transmission and another BWP is allocated for UL transmission.

Timing in Wireless System

In a wireless system, UL frame is transmitted by UE towards a base station whereas the DL frame is transmitted by the base station towards UE. There is one set of frames in the uplink and one set of frames in the downlink on a carrier. Uplink frame number i for transmission from the UE shall start TTAbefore the start of the corresponding downlink frame, as shown inFIG.7. TTAmay be based on various factors, as listed below:A round trip propagation delay for signals transmitted between UE and base station.A hardware switch time for switching between the TX mode and RX mode. For example, the switch time may be the time delay between deactivating RX module and activating TX module, or vice versa.Frequency range and band, as well as Sub-Carrier Spacing (SCS).

In some embodiments, TTA=(NTA+Nta_offset)*Tc. Tc is the basic time unit for a wireless system such as the 5G NR system. NTAmay be obtained by base station via detecting Physical Random Access Channel (PRACH) and/or UL reference signal. NTAmay be signaled to the UE via a timing advance command. Nta_offset may be predefined or may be informed by base station to the UE via signaling, such as the “n-TimingAdvanceOffset” signaling. Table 1 below shows example value for Nta_offset.

TABLE 1The Value of Nta_offsetFrequency range and band of cellNta_offsetused for uplink transmission(Unit: Tc)FR1 FDD or TDD band with neither E-UTRA-NR25600 (Note 1)nor NB-IoT-NR coexistence caseFR1 FDD band with E-UTRA-NR and/or0 (Note 1)NB-IoT-NR coexistence caseFR1 TDD band with E-UTRA-NR and/or39936 (Note 1)NB-IoT-NR coexistence caseFR213792Note 1:The UE identifies Nta_offset based on the information n-TimingAdvanceOffset. If UE is not provided with the information n-TimingAdvanceOffset, the default value of NTA offsetis set as 25600 for FR1 band. In case of multiple UL carriers in the same TAG, UE expects that the same value of n-TimingAdvanceOffset is provided for all the UL carriers. The value 39936 of Nta_offset can also be provided for a FDD serving cell.

In some embodiments, the base station and the UE may each maintain a UL timing and a DL timing. Referring toFIG.8, the timing advance (TA) for a UE may account for the round trip propagation delay (i.e., 2*Tprop). In addition, not shown inFIG.8, the timing advance may further be compensated based on Nta_offset.

From UE side, the reference point for the UE initial transmit timing may be the downlink timing of the reference cell minus the value of timing advance. The downlink timing may be the time when the first detected path (in time) of the corresponding downlink frame is received from the reference cell. In some implementations, DL timing may be obtained via the detection of DL reference signal, such as a Synchronization Signal Block (SSB), a Channel State Information Reference Signal (CSI-RS), or the like.

From the base station side, in example implementations, the UL timing is aligned with the DL timing.

Frame Structure and Slot Format Configuration

In a wireless network, various signaling and/or messages may be provided to configure time blocks (e.g., frame, slot, symbol, etc.). This may include the pattern as described in earlier section (e.g., the “DDDFU” pattern as shown inFIG.4), the periodicity of the pattern, etc.

The signaling may include cell specific signaling, for example, tdd-UL-DL-ConfigurationCommon. This signaling applies to all the UEs in one cell. Turning back toFIG.4, this signaling may indicate to the UEs: a pattern of the time blocks, and a periodicity of the time block pattern. For example, a “DDDFU” pattern with a periodicity of 2.5 ms may be signaled.

The indication/configuration described above uses slot as a unit in time domain. In some embodiments, the same underlying principle may apply to a symbol level to gain finer granularities. For example, the periodicity may be presented as a number of OFDM symbols (or equivalent time period corresponding to the number of OFDM symbols). Similarly, the format may also apply to the OFDM symbol. That is, the base station may indicate to the UE a format for each OFDM symbol, whether the symbol is for DL, UL, or flexible purpose.

The signaling may also include UE specific signaling, for example, tdd-UL-DL-ConfigurationDedicated. In some embodiments, the UE specific signaling may override the configuration indicated by the cell specific signaling.

In some embodiments, in case a UE is not provided with either a cell specific signaling or a UE specific signaling, the UE may assume that all slots and/or OFDM symbols are in flexible format.

Once a slot (or slots) or an OFDM symbol (or OFDM symbols) is configured as flexible format, the base station may dynamically schedule transmission resource in the slot or the OFDM symbol with desired direction, whether the direction is DL or UL. For example, referring toFIG.4, slot3is configured as an F slot. In the time domain, the base station may assign this whole slot or at least one OFDM symbol in this slot for UL transmission. In the frequency domain, this resource assignment may occupy all the resources blocks in the whole slot (or the at least one OFDM symbol), or just a portion of them. For example, assuming there is one single carrier in frequency domain which includes100resource blocks, in one example assignment, resource blocks11-20out of these100resource blocks in whole slot3may be assigned for UL transmission. In another assignment, resource blocks50-80out of these100resource blocks in OFDM symbols8-10of slot3may be assigned for UL transmission.

By using signaling described above, a transmission resource may be configured with an initial configuration including an initial pattern. Still referring toFIG.4, a slot pattern402may be configured as “DDDFU” using aforementioned signaling scheme. The slot pattern402may be configured with an exemple periodicity equal to2.5ms.

In some implementations, the transmission resource may be limited in a single cell, or a single carrier.

For implementing the SBFD feature, there are two types of SBFD transceiver structures.

In SBFD transceiver structure1, the Transmitting (Tx) antenna array and Receiving (Rx) antenna array are separated. Transmission and reception at a base station (e.g., gNB, ng-eNB, etc.) are each performed by a different set of Radio Frequency (RF) chains. Referring toFIG.6A, RF chain set1is the RX RF chain which always operates under RX mode, and RF chain set2is the TX RF chain which always operates under TX mode. RF chain set1covers DL slot0, DL portion of DL slots1and2, and DL portion of UL slots3and4. RF chain set2covers the UL sub-band in DL slots1and2, and UL portion of UL slots3and4. There needs to be isolation between these two set of RF chains to suppress self-interference. The structure1is simple and cost-efficient from design and implementation perspective. Self-interference cancellation is only needed in the RX RF chain. On hardware side, TX RF chain requires TX module whereas no RX module is needed, and the RX RF chain requires RX module whereas no TX module is needed. The downside of structure1is the loss of channel reciprocity which is critical for TDD system, especially TDD system with massive MIMO due to the isolation between the two set of RF chains. As background information, channel reciprocity may enable obtaining DL channel state via UL measurement, which may dramatically reduce Channel State Information (CSI) feedback overhead and boost TDD system performance. As background information, in a New Radio (NR) system, when one DL (or UL) channel/signal is configured as reference channel/signal for another UL (or DL) channel/signal, channel reciprocity can be assumed between the DL and UL channel/signal.

In SBFD transceiver structure2, the TX/RX antenna array is shared between different sets of RF chains at base station. Referring toFIG.6B, there exist RF chain set1and RF chain set2. At least one RF chain is configured with both TX module and RX module, for DL transmission and UL transmission, respectively. The RF chain may switch between DL and UL mode according to DL/UL allocation. For example, as shown inFIG.6B, RF chain set1is in DL mode in DL slot0-2, then switches to UL mode in slot3-4. For another example, RF chain set2is in UL mode in slots1-2(for the UL SB602), then switches to DL mode in slot3-4(for the DL SB604). It may be observed that in slots3and4, both RF chain sets are operating: RF chain set1operates in UL mode, and RF chain set2operates in DL mode.

In SBFD transceiver structure2, channel reciprocity may be achieved as the RF chain set is configured with both RX module and TX module. Note that there is still isolation between two sets of RF chains. However, the downside of structure2may include high complexity and cost, as more RX modules and TX modules are required, and each set of RF chain needs the functionality of self-interference cancellation.

Under SBFD implementation, if Nta_offset is set to larger than0as in legacy TDD system, the DL and UL sub-bands are not aligned in time domain, which imposes higher self-interference. As one solution, it is possible to make Nta_offset equal to 0. This may work for transceiver structure1since DL/UL switching is not needed when transmission and reception are implemented by two different sets of RF chains. However, for transceiver structure2, DL/UL switching may occur within a RF chain set and the switching time may not be ignored. Therefore, the assumption that Nta_offset is equal to0may not hold under transceiver structure2. The DL/UL switching time may need to be compensated under transceiver structure2implementation.

In this disclosure, various embodiments are described for obtaining DL and/or UL timing to realize alignment between the resources assigned with different link direction and to alleviate self-interference issue. Meanwhile, channel reciprocity is retained in these embodiments, which significantly reduce CSI feedback overhead and boost system performance.

In embodiments below, for exemplary purpose only, time unit in slot is used. Same underlying principle applies to other types of time blocks, such as symbol, frame, mini slot, etc.

In embodiments below, the slot configuration (or referred to as slot patter), such as “DDFFU”, is for exemplary purpose only. Same underlying principle applies to other slot patterns.

In embodiments below, a gNB is used as an example base station. Same underlying principle applies to other types of base stations, such as eNB, gn-eNB, eNodeB, etc.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.9, there are two UL timings configured for UE. For UL1transmitted in DL slot, a first UL timing, Tu_1=Nta is used. For UL2transmitted in UL slot, a second UL timing, Tu_2=Nta+Nta_offset is used. Detailed description for Nta and Nta_offset may be found in previous sections.

Meanwhile, there are two UL timings configured at gNB. The UL channel/signal in DL slot is aligned with timing of DL slot. The UL channel/signal in UL slot is aligned with timing of UL slot.

In some example implementations, the UL channel/signal may be generally referred to as a UL transmission, and the DL channel/signal may be generally referred to as a DL transmission.

In this embodiment, the slot configuration is DDFFU, which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.10, from UE side, the UL timing for UE in flexible slot may be configured as Tu_1=Nta, which is the same as the UL timing in DL slot.

Meanwhile, from gNB side, there are two UL timings at gNB. The UL channels/signals in DL slot and flexible slot are aligned with timing of DL slot. The UL channel/signal in UL slot is aligned with timing of UL slot.

In this embodiment, the slot configuration is DDFFU, which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.11, from UE side, the UL timing for UE in flexible slot may be configured as Tu_2=Nta+Nta_offset, which is the same as the UL timing in UL slot. For UL transmitted in DL symbols/slots, Tu_1=Nta may be used.

Meanwhile, from gNB side, there are two UL timings at gNB. The UL channels/signal in DL slot is aligned with timing of DL slot. The UL channel/signal in UL slot and flexible slot is aligned with timing of UL slot.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.12, from UE side, there are two DL timings configured for UE. For DL1transmitted in DL slot, a first DL timing, Td_1, may be obtained via, for example, the detection of SSB or CSI-RS. For DL2transmitted in UL slot, a second DL timing, Td_2=Td_1-Nta_offset may be configured.

Meanwhile, there are two DL timings at gNB. The DL channel/signal in DL slot is aligned with timing of DL slot. The DL channel/signal in UL slot is aligned with timing of UL slot, which may be Nta_offset ahead of DL timing of DL channel/signal in DL slot with a same slot index.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.13, from UE side, there are two DL timings configured for UE. For DLI transmitted in DL slot and DL3transmitted in flexible slot, a first DL timing, Td_1,may be obtained via, for example, the detection of SSB or CSI-RS. For DL2transmitted in UL slot, a second DL timing, Td_2=Td_1-Nta_offset may be configured.

Meanwhile, there are two DL timings at gNB. The DL channel/signal in DL slot and flexible slot is aligned with timing of DL slot. The DL channel/signal in UL slot is aligned with timing of UL slot, which may be Nta_offset ahead of DL timing of DL channel/signal in DL slot with a same slot index.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.14, from UE side, there are two DL timings configured for UE. For DLI transmitted in DL slot, a first DL timing, Td_1, may be obtained via, for example, detection of SSB or CSI-RS. For DL2transmitted in UL slot and DL3transmitted in flexible slot, a second DL timing, Td_2=Td_1-Nta_offset may be configured.

Meanwhile, there are two DL timings at gNB. The DL channel/signal in DL slot is aligned with timing of DL slot. The DL channel/signal in UL slot and flexible slot is aligned with timing of UL slot, which may be Nta_offset ahead of DL timing of DL channel/signal in DL slot with a same slot index.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

In previous embodiments, 2 DL timings and 2 UL timings for UE are described. In this embodiment, as shown inFIG.15, on the UE side, for flexible slot, the first DL timing Td_1 is used in combination with the first UL timing Tu_1.

In one implementation, Td_1 may be obtained via, for example, the detection of SSB or CSI-RS. Tu_1 may be configured as Nta.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

In previous embodiments, 2 DL timings and 2 UL timings for UE are described. In this embodiment, as shown in FIG. 16, for flexible slot, the second DL timing Td_2 is used in combination with the second UL timing Tu_2.

In one implementation, Tu_2=Nta+Nta_offset, and Td_2=Td_1-Nta_offset.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.17, for flexible slots2and3, the first DL timing Td_1 is used in combination with the first UL timing Tu_1. Notice that flexible slots2and3have both DL transmission and UL transmission scheduled. The previous slot of slot2is a DL slot, and the next slot of slot3is a UL slot. In this embodiment, a duration1702, which equals to Nta offset and is at the end of slot3is excluded from any UL/DL transmissions, including UL/DL channel/signals. The duration1702may serve as a guard interval for switching delay, for example, for an RF chain serving DLI in slot3to switch to UL mode to serve uplink transmission in UL slot4. Notice that the duration1702is at the end of continuous flexible slots. In case there is only one flexible slot in between slots of other formats, the duration1702is at the end of the only one flexible slot.

In one implementation, Td_1 may be obtained via, for example, the detection of SSB or CSI-RS. Tu_1 may be configured as Nta.

Notice that inFIG.17, from gNB side, flexible slot3and UL slot4have an overlap duration1704. This is to illustrate that the gNB is using two different timings. For example, the timing used for ULI or DLI in flexible slot3is different from the timing used for UL transmission in UL slot4.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.18, for flexible slots2and3, the first DL timing Td_1 is used in combination with the first UL timing Tu_1. Notice that flexible slots2and3have both DL transmission and UL transmission scheduled. The previous slot of slot2is a DL slot, and the next slot of slot3is a UL slot. In this embodiment, a duration1802which equals to 2*Nta_offset and is at the end of slot3is excluded from any UL/DL transmissions, including UL/DL channel/signals. The duration1802may serve as a guard interval for mode switching between DL mode and UL mode. Notice that the duration1802is at the end of continuous flexible slots. In case there is only one flexible slot in between slots of other formats, the duration1802is at the end of the only one flexible slot.

In one implementation, Td_1 may be obtained via, for example, the detection of SSB or CSI-RS. Tu_1 may be configured as Nta.

In this embodiment, the slot configuration is DDFFU (D: DL slot; U: UL slot; F: flexible slot), which may be indicated to the UE via cell specific signaling, such as “tdd-UL-DL-ConfigurationCommon”.

Referring toFIG.19, for flexible slots2and3, the second DL timing Td_2 is used in combination with the second UL timing Tu_2. Notice that flexible slots2and3have both DL transmission and UL transmission scheduled. The previous slot of slot2is a DL slot, and the next slot of slot3is a UL slot. In this embodiment, a duration1902which equals to Nta_offset and starts from beginning of slot2is excluded from any UL/DL transmissions, including UL/DL channel/signals. Notice that the duration1902start from the beginning of continuous flexible slots. In case there is only one flexible slot in between slots of other formats, the duration1902starts from the only one flexible slot.

In one implementation, Tu_2=Nta+Nta_offset, and Td_2=Td_1-Nta_offset.

Embodiments above describe that both base station and UE may each have two UL timings and two DL timings. The quantify of the UL/DL timings may be predefined, or may be indicated by the base station to the UE.

In one implementation, the gNB may signal the UE to add one UL/DL timing on top of existing timing.

In one implementation, the gNB may signal the UE to reduce the quantity of UL/DL timings to just one UL timing and/or one DL timing.

In one implementation, when there is only one UL timing, the first UL timing is configured or used. In this case, Nta_offset=0.

In one implementation, when there is only one DL timing, the first DL timing is configured or used. In this case, the DL timing may be obtained via the detection of DL reference signal, such as a SSB, a CSI-RS), or the like.

In above embodiments, the transmission resource may be limited in a single cell, or a single carrier.

The embodiments above may specifically apply to the SBFD transceiver structure2.

The description and accompanying drawings above provide specific example embodiments and implementations. The described subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein. A reasonably broad scope for claimed or covered subject matter is intended. Among other things, for example, subject matter may be embodied as methods, devices, components, systems, or non-transitory computer-readable media for storing computer codes. Accordingly, embodiments may, for example, take the form of hardware, software, firmware, storage media or any combination thereof. For example, the method embodiments described above may be implemented by components, devices, or systems including memory and processors by executing computer codes stored in the memory.

Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment/implementation” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment/implementation” as used herein does not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter includes combinations of example embodiments in whole or in part.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present solution should be or are included in any single implementation thereof. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present solution. Thus, discussions of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment.