Determine the timeline for transmitter switching

Abstract

This document relates to a method, system, and device for uplink transmitter switching in wireless communications. Wireless communications with uplink transmitter (Tx) switching may include optional user equipment (UE) capabilities that enable uplink (UL) transmission on a band where the number of Tx chains does not change during switching. One Tx chain may be maintained on a band during UL switching. The optional UE capabilities may include modification of the switching timeline. For example, UL transmission on a third band may occur during UL Tx switching between two other bands.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION This document is directed generally to wireless communications. More specifically, in mobile device communication systems, improved communications for uplink transmitter switching may exist. [Background technology]

[0002] Wireless communication technologies are moving the world toward an increasingly connected and networked society. Wireless communication relies on efficient network resource management and allocation between user mobile stations and radio access network nodes (including, but not limited to, radio base stations). New generation networks are expected to provide high-speed, low-latency, and ultra-reliable communication capabilities and fulfill requirements from different industries and users. User mobile stations or user equipment (UE) are becoming more complex, and the amount of data communicated continuously is increasing. Communication improvements should be made to improve communication for vertical markets, meet reliability requirements, and support new generation network services. Summary of the Invention [Means for solving the problem]

[0003] This document relates to a method, system, and device for uplink transmitter switching in wireless communications. Optional user equipment (UE) capabilities may enable uplink (UL) transmission on a band where the number of transmitter (Tx) chains does not change during switching. One Tx chain may be maintained on a band during UL switching. Optional UE capabilities may include modification of the switching timeline. For example, UL transmission on a third band may occur during UL Tx switching between two other bands.

[0004] In one embodiment, a method for wireless communication includes a method for wireless communication implemented by a wireless communication device, the method including receiving an indication of triggering an uplink (UL) transmitter (Tx) switch between two bands and transmitting a UL transmission on a third band during the UL Tx switch. The method includes transmitting the indication of triggering an uplink (UL) transmitter (Tx) switch between the two bands and triggering a UL transmission on the third band during the UL Tx switch. The two bands comprise a first band and a second band, and the switch is from the first band to the second band. The indication comprises a first downlink control information (DCI), and the UL transmission on the third band during the UL Tx switch is triggered by a second DCI. The second DCI for triggering the UL transmission on the third band is received before a gap before the start of the UL transmission on the second band after the UL Tx switch. The second DCI for triggering UL transmission on the third band is received after a gap before a start of UL transmission on the second band. The second DCI for triggering UL transmission on the third band is before a gap before a start of UL transmission on the third band. The first DCI for triggering UL transmission on the second band is received before a gap before a start of UL transmission on the third band.

[0005] In another embodiment, a method for wireless communication includes a method of wireless communication implemented by a wireless communication device, including receiving a trigger for two uplink (UL) transmission (Tx) chains to switch between two different band pairs, and identifying one port transmission on one band and one port transmission on another band after the switch as a single Tx switch based on a restriction. The restriction includes the two UL transmissions after the Tx switch being partially overlapped or the gap between the two UL transmissions being less than a threshold. The gap between the two UL transmissions is less than a threshold, and the two UL transmissions are in different slots. The threshold is a switch gap for the UL Tx switch. The restriction includes the two UL transmissions after the Tx switch being in a reference slot.

[0006] In another embodiment, a method for wireless communication includes a method of wireless communication implemented by a wireless communication device, the method including transmitting up to two uplink (UL) transmissions on a subset of bands from a band combination after a UL transmitter (Tx) switch and establishing conditions for the transmissions, wherein 3Tx is supported by the wireless communication device. One of the UL transmissions comprises a 1-port, 2-port, or 3-port transmission on one UL carrier on one band of the band combination. When the 2-port transmission on the UL carrier is on one band after the UL Tx switch and the preceding UL transmission with the 3Tx state is on another band, the Tx state after the UL Tx switch is 2Tx or 3Tx on one band depending on a parameter with two candidate values. When the 1-port transmission on the UL carrier is on one band after the UL Tx switch and the preceding UL transmission with the 3Tx state is on another band, the Tx state after the UL Tx switch is 1Tx, 2Tx, or 3Tx on one band depending on a parameter with three candidate values.

[0007] In one embodiment, a wireless communications device comprises a processor and a memory, the processor configured to read code from the memory and implement any of the embodiments discussed above.

[0008] In one embodiment, a computer program product has stored thereon a computer readable program medium code that, when executed by a processor, causes the processor to implement any of the embodiments discussed above.

[0009] In some embodiments, there is a wireless communication device comprising a processor and a memory, the processor configured to read code from the memory and implement any method recited in any of the embodiments. In some embodiments, a computer program product has stored thereon a computer-readable program medium code that, when executed by a processor, causes the processor to implement any method recited in any of the embodiments. These and other aspects and their implementations are described in more detail in the drawings, description, and claims. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows an exemplary base station.

[0011] [Figure 2] FIG. 2 illustrates an exemplary random access (“RA”) messaging environment.

[0012] [Figure 3] FIG. 3 shows a block diagram of an exemplary configuration of a transceiver and antenna.

[0013] [Figure 4] FIG. 4 shows a block diagram illustrating the relationship between carriers, bands, and cells.

[0014] [Figure 5a] FIG. 5a illustrates an embodiment of a user equipment (UE) baseline assumption.

[0015] [Figure 5b] FIG. 5b illustrates an embodiment of optional capabilities of a user equipment (UE).

[0016] [Figure 6] FIG. 6 shows an exemplary uplink (UL) transmission on band C overlapped with a transition gap.

[0017] [Figure 7] FIG. 7 shows another exemplary uplink (UL) transmission on band C that is overlapped with a transition gap.

[0018] [Figure 8a] FIG. 8a illustrates an embodiment of a user equipment (UE) baseline assumption with simultaneous transmissions.

[0019] [Figure 8b] FIG. 8b illustrates an embodiment of user equipment (UE) optional capabilities with simultaneous transmission.

[0020] [Figure 9] FIG. 9 shows an exemplary uplink (UL) transmission on band C overlapped with a transition gap with simultaneous transmission.

[0021] [Figure 10] FIG. 10 shows an embodiment with four zones.

[0022] [Figure 11] FIG. 11 shows an exemplary uplink (UL) transmission on four bands with switching gaps.

[0023] [Figure 12] FIG. 12 shows another exemplary uplink (UL) transmission on four bands with switching gaps.

[0024] [Figure 13] FIG. 13 shows a first exemplary transmission time frame on four bands with switching gaps.

[0025] [Figure 14] FIG. 14 shows a second exemplary transmission time frame on four bands with switching gaps.

[0026] [Figure 15]FIG. 15 shows a third exemplary transmission time frame on four bands with switching gaps. DETAILED DESCRIPTION OF THE INVENTION

[0027] Detailed Description The present disclosure will now be described in detail hereinafter with reference to the accompanying drawings, which form a part hereof and which show, by way of illustration, specific examples of embodiments. It should be noted, however, that the present disclosure may be embodied in a variety of different forms, and therefore, it is intended that the subject matter covered or claimed be construed as not being limited to any of the embodiments set forth below.

[0028] Throughout this specification and claims, terms may have nuanced meanings that are suggested or implied in context beyond those explicitly stated. Similarly, the phrases "in one embodiment" or "in some embodiments" as used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in other embodiments" as used herein do not necessarily refer to different embodiments. The phrases "in one implementation" or "in some implementations" as used herein do not necessarily refer to the same implementation, and the phrases "in another implementation" or "in other implementations" as used herein do not necessarily refer to different implementations. For example, it is intended that the claimed subject matter include, in whole or in part, a combination of example embodiments or implementations.

[0029] Generally, terminology can be understood, at least in part, from usage in context. For example, terms such as "and," "or," or "and / or," as used herein, can include a variety of meanings that may depend, at least in part, on the context in which such terms are used. Typically, when "or" is used to relate a list such as A, B, or C, it is intended to refer to A, B, and C, which are used herein in an inclusive sense, as well as A, B, or C, which are used herein in an exclusive sense. Additionally, the terms "one or more" or "at least one," as used herein, can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense, at least in part, depending on the context. Similarly, terms such as "a," "an," or "the" can be understood to convey singular use or to convey plural use, again, at least in part, depending on the context. Additionally, the terms "based on" or "determined by" may be understood as not necessarily intended to convey an exclusive set of factors, but instead may allow for the existence of additional factors not necessarily explicitly described, again depending at least in part on the context.

[0030] Based on current development trends, 4G and 5G systems are developing support for enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC) features. Full duplex may be a requirement for 5G and subsequent communication systems. In wireless communications, a network device such as a user equipment (UE) may perform uplink (UL) transmitter (Tx) switching within up to two bands. For multi-carrier operation, a network device transmitting with two transmitters (also referred to as a 2Tx user device) may transmit within two UL bands. The two bands used can be changed only by radio resource control (RRC) reconfiguration. A 2Tx user device may perform UL Tx switching between two UL bands. The UL Tx switching scheme may not allow a user device to perform UL Tx switching involving three or more bands and simultaneous transmission with two transmitters, enable more configured UL bands than its simultaneous transmission capacity, and / or support dynamic Tx carrier switching across configured bands. Dynamic carrier selection using UL Tx switching (e.g., based on data traffic, TDD downlink (DL) / uplink (UL) configuration, bandwidth of each band, and channel conditions instead of RRC-based cell reconfiguration) can potentially lead to higher UL data rates, spectrum utilization, and UL capacity. UL Tx switching schemes across up to three, four, or more bands (including mechanisms to enable more configured UL bands than its simultaneous transmission capacity and to support dynamic Tx carrier switching across configured bands) with a limit of a maximum of two Tx simultaneous transmissions for FR1 UEs may not be fully supported without the embodiments described below.

[0031] Radio Resource Control ("RRC") is a protocol layer between a UE and a base station at the IP level (network layer). Various Radio Resource Control (RRC) states may exist, such as RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE. RRC messages are transported via the Packet Data Convergence Protocol ("PDCP"). As described, a UE can transmit data through a Random Access Channel ("RACH") protocol scheme or a Configured Grant ("CG") scheme. CG may be used to reduce waste of periodically allocated resources by allowing multiple devices to share periodic resources. A base station or node may allocate CG resources to eliminate packet transmission delays and increase utilization of allocated periodic radio resources. The CG scheme is merely one example of a protocol scheme for communication; other examples, including but not limited to RACH, are also possible. Wireless communication described herein may be through radio access.

[0032] 1 shows an exemplary base station 102. A base station may also be referred to as a network device or a radio network node. The base station 102 may further be identified as a nodeB (NB, e.g., eNB or gNB) in a mobile telecommunications context. The exemplary base station may include radio Tx / Rx circuitry 113 for receiving and transmitting with a user equipment (UE) 104. The base station may also include network interface circuitry 116 for coupling the base station to a core network 110, e.g., optical or wired interconnects, Ethernet, and / or other data transmission media / protocols.

[0033] The base station may also include system circuitry 122. The system circuitry 122 may include a processor 124 and / or a memory 126. The memory 126 may include operations 128 and control parameters 130. The operations 128 may include instructions for execution on one or more of the processors 124 to support the functioning of the base station. For example, the operations may handle random access transmission requests from multiple UEs. The control parameters 130 may include parameters or support the execution of the operations 128. For example, the control parameters may include network protocol settings, random access messaging formatting rules, bandwidth parameters, radio frequency mapping assignments, and / or other parameters.

[0034] Additionally, signals communicated between communication nodes in the system 100 may be characterized or defined as data signals or control signals. Generally, data signals are signals that contain or carry data, such as multimedia data (e.g., voice and / or image data), and control signals are signals that carry control information that configure communication nodes in some manner to communicate with each other or otherwise control how communication nodes communicate data signals with each other. Certain signals may also be defined or characterized by combinations of data / control and uplink / downlink / sidelink, including uplink control signals, uplink data signals, downlink control signals, downlink data signals, sidelink control signals, and sidelink data signals. Certain signals can also be characterized or defined as either uplink (UL) signals, downlink (DL) signals, or sidelink (SL) signals. Uplink signals are signals transmitted from the UE 104 to the base station 102. Downlink signals are signals transmitted from the base station 102 to the UE 104. A sidelink signal is a signal transmitted from one UE 104 to another UE 104.

[0035] For at least some specifications, such as 5G New Radio (NR), data and control signals are transmitted and / or carried on physical channels. Generally, a physical channel corresponds to a set of time-frequency resources used for the transmission of signals. Different types of physical channels may be used to transmit different types of signals. For example, a physical data channel (or simply a data channel), also referred to herein as a traffic channel, is used to transmit data signals, and a physical control channel (or simply a control channel) is used to transmit control signals. Exemplary types of traffic channels (or physical data channels) include, but are not limited to, a physical downlink shared channel (PDSCH), used to communicate downlink data signals, a physical uplink shared channel (PUSCH), used to communicate uplink data signals, and a physical sidelink shared channel (PSSCH), used to communicate sidelink data signals. Additionally, exemplary types of physical control channels include, without limitation, a physical downlink control channel (PDCCH) used to communicate downlink control signals, a physical uplink control channel (PUCCH) used to communicate uplink control signals, and a physical sidelink control channel (PSCCH) used to communicate sidelink control signals. As used herein for simplicity, unless otherwise specified, a physical channel of a particular type is also used to refer to a signal transmitted on that particular type of physical channel and / or a transmission on that particular type of transmission. As an exemplary illustration, a PDSCH refers to the physical downlink shared channel itself, a downlink data signal transmitted on the PDSCH, or a downlink data transmission. Thus, a communication node transmitting or receiving a PDSCH means that the communication node is transmitting or receiving a signal on the PDSCH.

[0036] Additionally, for at least some specifications, such as 5G NR, and / or for at least some types of control signals, control signals transmitted by communication nodes may include control information comprising information necessary for enabling transmission of one or more data signals between communication nodes and / or for scheduling one or more data channels (or one or more transmissions on a data channel). For example, such control information may include information necessary for proper reception, decoding, and demodulation of data signals received on a physical data channel during a data transmission and / or for an uplink scheduling grant, which informs a user device about resources and transport formats to use for an uplink data transmission. In some embodiments, the control information includes downlink control information (DCI), which is transmitted in the downlink direction from the base station 102 to the UE 104. In other embodiments, the control information includes uplink control information (UCI), which is transmitted in the uplink direction from the UE 104 to the base station 102, or sidelink control information (SCI), which is transmitted in the sidelink direction from one UE 104 to another UE 104.

[0037] Additionally, in some embodiments, the UE 104 may be configured to support at least one simultaneous UL transmission mode across a band pair for UE transmission. In a first simultaneous UL transmission mode (also referred to as a switched UL mode), the UE 104 does not support simultaneous UL transmission across a band pair. Thus, when the UE 104 transmits a UL transmission in the first simultaneous UL transmission mode, the UE 104 transmits the UL transmission without simultaneously transmitting across the band pair. Additionally, in a second simultaneous UL transmission mode (also referred to as a dual UL mode), the UE 104 supports simultaneous UL transmission across the band pair. Thus, when the UE 104 transmits a UL transmission in the second simultaneous UL transmission mode, the UE 104 may transmit the UL transmission by simultaneously transmitting across the band pair.

[0038] In some embodiments, the UE 104 may also report a simultaneous UL transmission mode to the base station 102. That is, the UE 104 may report to the base station 102 that it supports simultaneous UL transmission across a band pair, that it does not support simultaneous UL transmission across a band pair, or that it both supports and does not support simultaneous UL transmission across a band pair. In certain of these embodiments, the UE 104 may report whether it supports simultaneous UL transmission across a band pair per band combination (BC). The base station 102 may also configure a simultaneous UL transmission mode (e.g., switchedUL or dualUL) per cell group, which may be considered per BC or per band pair in embodiments where a 2-Tx user device supports only two bands. That is, one available band pair in a band combination may support one simultaneous UL transmission mode.

[0039] Additionally, as generally used herein, a band combination may include multiple bands (e.g., five bands). Additionally, as used herein, a band group may include up to three or four bands. A given band group may be included in or be part of a band combination. Also, a band combination and / or band group may include at least one band pair, where a band pair includes two bands.

[0040] 2 illustrates an exemplary random access messaging environment 200. In the random access messaging environment, a UE 104 may communicate with a base station 102 via a random access channel 252. In this example, the UE 104 supports one or more subscriber identity modules (SIMs), such as SIM1 202. An electrical and physical interface 206 connects SIM1 202 to the rest of the user equipment hardware, for example, through a system bus 210.

[0041] The mobile device 200 includes a communications interface 212, system logic 214, and a user interface 218. The system logic 214 may include any combination of hardware, software, firmware, or other logic. The system logic 214 may be implemented with, for example, one or more systems on a chip (SoC), application specific integrated circuits (ASICs), discrete analog and digital circuits, and other circuitry. The system logic 214 is part of the implementation of any desired functionality within the UE 104. In that regard, system logic 214 may include, by way of example, logic that facilitates music and video decoding and playback, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback, application launching, user input acceptance, saving and retrieving application data, as one example, establishing, maintaining, and terminating cellular phone calls or data connections for Internet connectivity, establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections, and displaying related information on user interface 218. User interface 218 and input 228 may include a graphical user interface, a touch-sensitive display, tactile feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Additional examples of input 228 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.

[0042] The system logic 214 may include one or more processors 216 and a memory 220. The memory 220 stores, for example, control instructions 222 that the processor 216 executes to perform desired functionality for the UE 104. Control parameters 224 provide and define configuration and operating options for the control instructions 222. The memory 220 may also store any BT, WiFi, 3G, 4G, 5G, or other data 226 that the UE 104 will transmit or receive through the communication interface 212. In various implementations, system power may be provided by a power storage device, such as a battery 282.

[0043] In the communications interface 212, radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 230 handles the transmission and reception of signals through one or more antennas 232. The communications interface 212 may include one or more transceivers. The transceiver may be a wireless transceiver including modulation / demodulation circuitry, digital-to-analog converters (DACs), shaping tables, analog-to-digital converters (ADCs), filters, waveform shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving through one or more antennas or (for some devices) over a physical (e.g., wired) medium.

[0044] Transmitted and received signals may conform 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, communication interface 212 may include a transceiver supporting transmission and reception under 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA)+, and 4G / Long Term Evolution (LTE) standards. However, the techniques described below are also applicable to other wireless communication technologies, whether arising from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnership or standards body.

[0045] Multiple RAN nodes (e.g., eNBs, gNBs) of the same or different radio access technologies ("RATs") can be deployed on the same or different frequency carriers within a geographic area, and they can cooperate with each other via dual connectivity operation to provide joint communication services for the same target UE. A multi-RAT dual connectivity ("MR-DC") architecture may have a non-co-located master node ("MN") and secondary node ("SN"). The access mobility function ("AMF") and session management function ("SMF") may be control plane entities, and the user plane function ("UPF") is a user plane entity in new radio ("NR") or 5GC.

[0046] 3 shows a block diagram of an example configuration of the transceiver 212 and the antenna 232. In particular, the transceiver 212 includes a first transmitter (Tx) (or transmitter circuit) 302(1) and a second transmitter (Tx) (or transmitter circuit) 302(2). In addition, the antenna 232 may include a first antenna component 304(1) and a second antenna component 304(2). In general, the first transmitter 302(1) and the first antenna component 304(1) may form a first transmitter channel or chain, and the second transmitter 302(2) and the second antenna component 304(2) may form a second transmitter channel or chain. A UE 104 with the configuration of FIG. 2 may be configured to transmit a first UL transmission (or a first portion of the UL transmission) using a first transmitter channel and may be configured to transmit a second UL transmission (or a second portion of the UL transmission) using the first transmitter channel.

[0047] In some embodiments, the UE 104 may transmit on one or two bands or carriers using two transmitter channels. The UE 104 may do so in any of a variety of ways. For example, the UE 104 may transmit on a single carrier using both the first transmission channel and the second transmission channel. As another example, the UE 104 may transmit on a first carrier using the first transmission channel and on a second carrier using the second transmission channel. As used herein, the terms “1Tx” and “1T” refer to the use of one channel to transmit on one carrier, and the terms “2Tx” and “2T” refer to the use of two transmission channels to transmit on one carrier. Additionally, as used herein, the phrase “UL transmission case” refers to a particular configuration of transmission channels used for UL transmission on one or more carriers. Also, as described in more detail below, the UE 104 may switch between UL transmission cases during a UL Tx switching operation. Table 1 below lists two exemplary UL transmission cases, Case 1 and Case 2. [Table 1]

[0048] Table 1 shows that for a first UL transmission case (Case 1), the UE 104 transmits UL transmissions on two carriers using one transmission channel (1 Tx) per carrier, such as by using a first transmission channel for transmission on a first carrier (Carrier 1) and a second transmission channel for transmission on a second carrier (Carrier 2). Additionally, Table 1 shows that for a second UL transmission case (Case 2), the UE 104 transmits UL transmissions on only one carrier, using two transmission channels (2 Tx) for transmission on the second carrier. For this second case, the UE 104 does not use any transmission channels for transmission on the first carrier.

[0049] Additionally, in various embodiments, the UE 104 may perform UL transmitter (Tx) switching to perform UL transmission. Generally, the UE 104 may perform UL Tx switching by switching from one UL transmission case to another UL transmission case. In operation, the UE 104 may transmit a UL transmission according to a first UL transmission case, then switch from the first UL transmission case to a second UL transmission case and transmit a UL transmission according to the second transmission case. To illustrate, using Table 1, for example, the user device may transmit a UL transmission according to Case 1 by transmitting on a first carrier using a first transmitter chain and on a second carrier using a second transmitter channel, etc. The UE 104 may then switch from Case 1 to Case 2 and then transmit a UL transmission according to Case 2 by transmitting on the second carrier using both the first and second transmitter channels, etc.

[0050] In various embodiments, the type of UL Tx switching performed by the UE 104 may be referred to as 1Tx-2Tx switching, such as with reference to Table 1. For 1Tx-2Tx switching, the UE 104 may switch from using one transmitter channel to transmit on the channel to using two transmitter channels to transmit on the channel, or may switch from using two transmitter channels to transmit on the channel to one transmitter channel.

[0051] Additionally, in various embodiments, the UL transmission case may also identify the number of antenna ports corresponding to the carrier. The identification may be in the form of a mapping between the carrier and the respective number of antenna ports. For at least some of these embodiments, the number of antennas may depend on whether the UE 104 supports simultaneous transmission across a band pair. Table 2 shows example UL transmission cases when simultaneous transmission across a band pair is not supported and when the UE 104 applies carrier aggregation including a complementary UL (SUL) band. [Table 2]

[0052] In the example illustrated in Table 2, for a first UL transmission case (Case 1), the UE 104 transmits on the first carrier using the first transmission channel and transmits on the second carrier using the second transmission channel. Also, based on the UE 104 not supporting simultaneous transmission across the band pair, the number of antenna ports for UL transmission on the first carrier is 1, and the number of antenna ports for UL transmission on the second carrier is zero (1P+0P). Additionally, for a second UL transmission case (Case 2), the UE 104 transmits on the second carrier using both the first and second transmission channels. Also, based on the UE 104 not supporting simultaneous transmission across the band pair, the number of antenna ports for the two carriers can be one of two options. In the first option, the number of antenna ports for the first carrier is zero, and the number of antenna ports for the second carrier is two. In a second option, the number of antenna ports for the first carrier is zero and the number of antenna ports for the second carrier is one.

[0053] Table 3 shows an exemplary UL transmission case when simultaneous transmission across band pairs is supported. [Table 3]

[0054] In the example illustrated in Table 3, for a first UL transmission case (Case 1), the UE 104 transmits on the first carrier using a first transmission channel and transmits on the second carrier using a second transmission channel. Also, based on the fact that the UE 104 supports simultaneous transmission across a band pair, the number of antenna ports for UL transmission can be one of three options. In the first option, the number of antenna ports for the first carrier is one, and the number of antenna ports for the second carrier is zero. In the second option, the number of antenna ports for the first and second carriers is one, respectively. In the third option, the number of antenna ports for the first carrier is zero, and the number of antenna ports for the second carrier is one. In the second UL transmission case, the UE 104 does not transmit on the first carrier using any transmitter chain, and transmits on the second carrier using two transmitter chains. Also, based on the UE 104 now supporting simultaneous transmission across the band pair, the number of antenna ports for UL transmission can be one of two options: In the first option, the number of antenna ports for the first carrier is zero and the number of antenna ports for the second carrier is two; In the second option, the number of antenna ports for the first carrier is zero and the number of antenna ports for the second carrier is one.

[0055] As mentioned above, the UE 104 may perform 1Tx-2Tx UL Tx switching, in which the UE 104 switches between one transmission channel and two transmission channels for transmission on a channel. Another type of UL Tx switching may include 2Tx-2Tx switching, in which the UE 104 switches from using two transmitter channels for transmission on a carrier to using two transmitter channels for transmission on another carrier. Tables 4 and 5 below illustrate examples of 2Tx-2Tx UL Tx switching. [Table 4] [Table 5]

[0056] Referring to Table 4, in a first example of 2Tx-2Tx UL Tx switching, in a first transmission case (Case 1), the UE 104 transmits on the second carrier using two transmitter channels and does not transmit on the first carrier using any transmitter channels. In a second transmission case (Case 2), the UE 104 transmits on the first carrier using two transmitter channels and does not transmit on the second carrier using any transmitter channels. For 2Tx-2Tx UL Tx switching, the UE 104 may switch from the first transmission case to the second transmission case or from the second transmission case to the first transmission case.

[0057] Referring to Table 5, the UE 104 may use a combination of 1Tx-2Tx switching and 2Tx-2Tx switching. For example, in Table 5, Case 1 corresponds to Case 1 in Table 2, and Cases 2 and 3 correspond to Cases 1 and 2, respectively, in Table 4. The UE 104 may perform 1Tx-2Tx switching by switching between Case 1 and Case 2 and / or between Case 1 and Case 3, and may perform 2Tx-2Tx switching by switching between Case 2 and Case 3.

[0058] Also, in various embodiments, the UL transmission case may also identify the number of antenna ports corresponding to the carrier for 2Tx-2Tx switching, such as in the form of a mapping between carriers and individual numbers of antenna ports similar to Tables 2 and 3 above, which show the mapping between carriers and numbers of antenna ports for 1Tx-2Tx switching. The mapping may depend on whether the UE 104 supports simultaneous switching across band pairs. Table 6 below shows an exemplary UL transmission case with a mapping of the number of antenna ports for 2Tx-2Tx switching where the UE 104 does not support simultaneous transmission across band pairs. Table 7 below shows an exemplary UL transmission case with a mapping of the number of antenna ports for 2Tx-2Tx switching where the UE 104 supports simultaneous transmission across band pairs. [Table 6] [Table 7]

[0059] Additionally, in various embodiments, the UE 104 may perform 1Tx-2Tx and / or 2Tx-2Tx UL Tx switching for the bands. For example, one carrier may be on one band (e.g., Band A) and two carriers, such as two consecutive carriers, may be on another band (e.g., Band B). For at least some of these embodiments, the band with one carrier may be a complementary UL (SUL) band, and the band with two consecutive carriers may be a non-SUL or normal UL (NUL) band. For at least some of these examples, the UE 104 may perform UL Tx switching between any two or three of the following cases for the first band and the second band (i.e., Band A + Band B): Case 1: 1T+1T, Case 2: 0T+2T, Case 3: 2T+0T.

[0060] Additionally, for embodiments in which the UE 104 performs UL Tx switching for a band, the UL transmission case may identify the number of antenna ports for the carriers of the band, similar to Tables 2, 3, 6, and 7 above. Tables 8-11 show various UL transmission cases with antenna port number mapping for two bands, where the first band (Band A) includes one carrier and the second band (Band B) includes three carriers, with two consecutive carriers. Table 8 shows an example UL transmission case for 1Tx-2Tx UL Tx switching in which the UE 104 does not support simultaneous transmission across the band pair. Table 9 shows an example UL transmission case for 1Tx-2Tx UL Tx switching in which the UE 104 supports simultaneous transmission across the band pair. Table 10 shows an example UL transmission case for 2Tx-2Tx UL Tx switching in which the UE 104 does not support simultaneous transmission across the band pair. Table 11 shows an exemplary UL transmission case for 2Tx-2Tx UL Tx switching where the UE 104 supports simultaneous transmission across a band pair. [Table 8] [Table 9] [Table 10] [Table 11]

[0061] In some embodiments, the UE 104 may be configured with three bands for which to perform UL Tx switching and for which to transmit UL transmissions. The three bands may include a first band (Band A), a second band (Band B), and a third band (Band C). For at least some of these embodiments, the UE 104 may dynamically select any two of these three bands for performing UL Tx switching. In various of these embodiments, the three bands may include various combinations of SUL bands and normal or non-SUL (NUL) bands, with examples of two scenarios being as follows: In a first scenario (Scenario 1), Band A is a SUL or non-SUL band, Band B is a non-SUL band, and Band C is a SUL or non-SUL band. That is, Band C is similar to Band A. In one example of Scenario 1, Band A includes a first carrier (Carrier 1), Band B includes a second carrier (Carrier 2), and Band C includes a third carrier (Carrier 3). In a second example of Scenario 1, Band A includes Carrier 1, Band B includes Carriers 2 and 3, and Band C includes a fourth carrier (Carrier 4). In a second scenario (Scenario 2), Band A is a SUL or non-SUL band, Band B is a non-SUL band, and Band C is a non-SUL band. That is, Band C is similar to Band B. In one example of Scenario 2, Band A includes Carrier 1, Band B includes Carrier 2, and Band C includes Carriers 3 and 4. In a second example of Scenario 2, Band A includes Carrier 1, Band B includes Carriers 2 and 3, and Band C includes Carrier 4 and a fifth carrier (Carrier 5).

[0062] Additionally, in various other embodiments, the UE 104 may be configured with four bands, including a first band (Band A), a second band (Band B), a third band (Band C), and a fourth band (Band D), for which to perform UL Tx switching and to transmit UL transmissions among the four bands. Similar to the three-band configuration, the UE 104 may dynamically select any two of the four bands for performing UL Tx switching. In various of these embodiments, the four bands may include various combinations of SUL and NUL bands, with examples of two scenarios being as follows: In a first scenario (Scenario 1), Band A is a SUL or non-SUL band, Band B is a non-SUL band, and Band C is a SUL or non-SUL band. That is, Band C is similar to Band A. In a first example of Scenario 1, Band A includes a first carrier (Carrier 1), Band B includes a second carrier (Carrier 2), Band C includes a third carrier (Carrier 3), and Band D includes a fourth carrier (Carrier 4). In a second example of Scenario 1, Band A includes Carrier 1, Band B includes Carrier 2, Band C includes Carrier 3, and Band D includes Carrier 4 and a fifth carrier (Carrier 5). In a third example of Scenario 1, Band A includes Carrier 1, Band B includes Carriers 2 and 3, Band C includes Carrier 4, and Band D includes Carrier 5. In a fourth example of Scenario 1, Band B includes Carrier 1, Band B includes Carriers 2 and 3, Band C includes Carrier 4, and Band D includes Carrier 5 and a sixth carrier (Carrier 6). In a second scenario (Scenario 2), Band A is a SUL or non-SUL band, Band B is a non-SUL band, and Band C is a non-SUL band. That is, Band C is similar to Band B. In a first example of Scenario 2, Band A includes Carrier 1, Band B includes Carrier 2, Band C includes Carriers 3 and 4, and Band D includes Carrier 5. In a second example of Scenario 2, Band A includes Carrier 1, Band B includes Carrier 2, Band C includes Carriers 3 and 4, and Band D includes Carriers 5 and 6. In a third example of Scenario 2, Band A includes Carrier 1, Band B includes Carriers 2 and 3, Band C includes Carriers 4 and 5, and Band D includes Carrier 6. In a fourth example of Scenario 2, Band A includes Carrier 1, Band B includes Carriers 2 and 3, Band C includes Carriers 4 and 5, and Band D includes Carriers 6 and 7.

[0063] Also, regarding an embodiment in which the UE 104 performs dynamic Tx carrier switching across configured bands, at least one of the following options is possible: In a first option, the UE 104 may perform dynamic Tx carrier switching across all supported UL transmission cases supported by the UE and based on UL scheduling, i.e., via an UL grant and / or RRC configuration for UL transmission; In a second option, the base station 102 may indicate two of the configured bands (three or four bands) via DCI or a medium access control (MAC) control element (CE); In a third option, the UE 104 may select one anchor band of the configured bands (three or four bands) and perform dynamic Tx carrier switching from the anchor band to non-anchor bands and / or from non-anchor bands to only the anchor band;

[0064] Table 12 shows an example set of 10 UL transmission cases for four bands with antenna port number mapping. The second column of Table 12 shows the antenna port numbers for when the UE 104 does not support simultaneous transmission across multiple carriers, and the third column shows the antenna port numbers for when the UE 104 supports simultaneous transmission across up to two carriers. [Table 12]

[0065] For embodiments in which UE 104 supports all UL transmission cases according to the first option above (e.g., all 10 UL transmission cases in Table 12), UE 104 may switch between any two UL transmission cases without any additional restrictions. For example, assume that UE 104's current transmission state is transmitting on two carriers on two bands, using one transmission channel to transmit on each band, and UE 104 should switch between two different carriers on two different bands, but still using one transmission channel to transmit on each band. For example, UE 104 may switch from Case 1 to Case 8. Corresponding to Cases 1 and 8 in Table 12, UE 104 may transmit a first transmission on carrier 1 in cell 1 and carrier 2 in cell 2 (Case 1), then switch and transmit a second transmission on carrier 3 in cell 3 and carrier 4 in cell 4 (Case 8).

[0066] The mechanism for dynamic Tx carrier switching across configured bands can be dynamic Tx carrier switching across all supported switching cases by the UE and based on UL scheduling, i.e., via dynamic grant and / or RRC configuration for UL transmission. In an embodiment, "all supported switching cases" are all entries of the "superset" as shown in Table 12, without any additional restrictions. For example, if the current Tx state is two carriers on two bands with one Tx on each band and is switched to two carriers on another two bands with one Tx on each band, it is a Tx switch between Case 1 and Case 8, which can be considered as UL transmission on carrier 1 in cell 1 and carrier 2 in cell 2 being switched to carrier 3 in cell 3 and carrier 4 in cell 4, as shown in FIG. 4. FIG. 4 shows a block diagram illustrating the relationship between carriers, bands, and cells.

[0067] Two bands can be configured for the UE to perform TX switching. Of the two bands, Band A (e.g., Carrier 1) is for SUL or non-SUL, and Band B (Carrier 2 only, or Carrier 2 and Carrier 3) is a non-SUL band. In an example, three bands (e.g., Band A + Band B + Band C) are configured. Only two bands may be dynamically selected from among them to perform UL TX switching. Assuming that Band C may be similar to Band A or Band B, the following alternatives may be derived. The following describes various embodiments related to restrictions or criteria regarding how to configure or determine cells / carriers / bands among the three or four bands for UL Tx switching, including those related to configurations where the UE 104 does or does not support simultaneous transmission across the band pair, and how to report or configure switching within the three or four bands.

[0068] In embodiments in which one of two Tx chains is triggered to switch from one band (e.g., "Band A") to another band (e.g., "Band B"), the other Tx chain may be maintained on a different band (e.g., "Band C"), and the number of Tx chains on Band C may not change due to the switch. The baseline UE assumption may be that none of the Tx chains are expected to be used for transmission during the switch period. An optional UE capability allows UL transmission on a band where the number of Tx chains does not change during the UL switch (i.e., one Tx chain is maintained on the band). The embodiments described herein determine the timeline for applying this optional UE capability. In an embodiment where a UE is to transmit 1 port+1 port (1P+1P) transmissions on one UL carrier on different bands (e.g., the first and second bands), if the Tx chain state in the preceding uplink transmission is 1T+1T on carriers on other different bands (e.g., the third and fourth bands), some embodiments determine a timeline for implementing this as a single Tx switch. For simplicity, the following embodiments focus on one example timeline issue for three or four band switches. Other embodiments may exist that are also related to a switch involving three Txs.

[0069] In some embodiments, the uplink switching gap N Tx1-Tx2 The UE may have an uplink switching gap N if the conditions defined in this section are met and the UE is configured with uplinkTxSwitching. Tx1-Tx2 The uplink transmission during the transition gap N Tx1-Tx2may be indicated by the UE capability uplinkTxSwitchingPeriod2T2T or using uplinkTxSwitchingPeriod if uplinkTxSwitching-2T-Mode is configured. For a UE configured with uplinkTxSwitchingOption set to "switchedUL", when the UE is to transmit a one-port transmission on one uplink carrier on one band, if the preceding uplink transmission was a one-port transmission on another uplink carrier on another band, the UE shall Tx1-Tx2 In some embodiments, the UE is expected to transmit all uplink transmissions successfully without interruption. In RAN4 specifications, for example, an uplink switching period may exist. The switching period may be located on either NR carrier 1 or carrier 2 as indicated in RRC signaling uplinkTxSwitchingPeriodLocation, and the length X of the uplink switching period may be less than the value indicated by the UE capability uplinkTxSwitchingPeriod.

[0070] The UE may first report a band combination to the base station (the band combination may include many bands, for example, five bands), and the band combination signaling further includes one or more band pairs, each band pair including two bands. For example, the base station may configure a PCell and an SCell for the UE, and the PCell and the SCell may fulfil the ones from one band pair. A switching period may be reported for each band pair. For each switching between two cases, i.e., for up to two Tx switching between two carriers in a band pair, the switching period may be one of {35 μs, 140 μs, 210 μs}, which is reported by the UE for each band pair.

[0071] The switching option may be reported per band combination. For example, "switchedUL" or "dualUL" or "both" may be reported by the UE per band combination (BC), and supportedBandPairListNR may also be reported for the BC. For example, "switchedUL" or "dualUL" may be configured by the base station per cell group, which may be considered per BC or per band pair. One available band pair in a BC may support one type of carrier aggregation (CA) option, and a different CA option may be applied upon RRC reconfiguration if the UE reports "both." CA option 1 may be "switchedUL," i.e., parallel transmission across two bands is not supported, while CA option 2 is "dualUL," i.e., parallel transmission across two bands is supported.

[0072] 5a illustrates an embodiment of a user equipment (UE) baseline assumption. When a UE is to transmit a one-port transmission on one uplink carrier on one band, if the preceding uplink transmission was a one-port transmission on another uplink carrier on another band, the UE may transmit N uplink transmissions on any of the carriers. Tx1-Tx2 As shown, band C is not communicating.

[0073] 5b illustrates an embodiment of user equipment (UE) optional capabilities. The UE optional processing capabilities include enabling communication in band C. The embodiments described below include example timelines for utilizing the UE optional processing capabilities. In one embodiment, there may be three bands A, B, and C, which are configured bands for implementing Tx switching, as shown in Table 13. [Table 13]

[0074] In one embodiment, the transmission switching option parameter (e.g., uplinkTxSwitchingOption) may be set to "switchUL" and may also be referred to as CA option 1, which means that parallel transmission between two bands is not supported, which can also be applied for SUL scenarios. Alternatively, the transmission switching option parameter (e.g., uplinkTxSwitchingOption) may be set to "dualUL" and may also be referred to as CA option 2, which means that parallel transmission between two bands is supported. Under "switchUL" operation, uplink transmission can be conducted on one band before or after switching within band combination A and B and C. Switching periods are reported for band pair A and B, band pair B and C, and band pair A and C, respectively, with the same or different values. Under "dualUL" operation, uplink transmission can be conducted on one or two bands before or after switching within band combination A and B and C. The switching period is reported for band pair A and B, band pair B and C, and band pair A and C, respectively, with the same or different values, and the switching gap is determined by the larger of the two switching periods when two band pairs are involved in UL Tx switching. In embodiments with SUL or CA switched UL, there is a Tx switch where 1P on band A is switched to 1P on band B, and 1P's transmission on band C may be unexpected based on the baseline UE assumptions. Alternatively, when switch AB is first triggered, the UE may be unexpected for UL transmission on band C, which overlaps with the gap. In other words, scheduling may be unexpected, or the UE may omit / cancel UL transmission on band C. Alternatively, if UL transmission on band C is scheduled first, switch AB may result in the UE omitting / cancelling UL transmission on band C.

[0075] FIG. 6 shows uplink (UL) transmission on Band C overlapping with the switching gap between Band A and Band B. If an uplink switch is triggered for an uplink transmission start at T0, after T0-Toffset, the UE may not be expected to cancel the uplink switch or trigger any other new uplink switch occurring before T0 for any other uplink transmission scheduled after T0-Toffset. Toffset may be the UE processing procedure time (e.g., the UE PUSCH preparation procedure time) defined for the uplink transmission triggering the switch. For the baseline UE assumption (e.g., FIG. 5a), none of the Tx chains may be expected to be used for transmission on Band C during the switching period. Meanwhile, for optional UE capabilities (e.g., FIG. 5b), UL transmission on Band C may be enabled during a UL switch from Band A to Band B or from Band A+C to Band B+C, with the number of Tx chains unchanged (i.e., one Tx chain is maintained on the band).

[0076] There may be timeline restrictions to be applied to optional UE capabilities (e.g., FIG. 5b). In a first optional embodiment, a DCI used to trigger UL transmission on band C before T0-Toffset may be applied, where T0 and Toffset refer to uplink transmission on band B after UL Tx switching. As shown in FIG. 6, T0 is T01 and Toffset is Toffset1. In other words, DCI1 may be used to schedule UL transmission on band C if the UL transmission on band C overlaps with the gap in UL switching from band A to band B. In other words, DCI2 may not be used to schedule UL transmission on band C if the UL transmission on band C overlaps with the gap in UL switching from band A to band B. In the absence of any UL Tx switching from band A to band B, DCI2 used to trigger UL transmission on band C before T02-Toffset2 may be applied. This exemplary embodiment may be applied for optional UE capabilities (e.g., FIG. 5b) and with the timeline restriction that DCI is only valid for triggering UL transmission on band C before T0-Toffset of uplink transmission on other bands after UL Tx switching.

[0077] In a second optional embodiment, a DCI may be used to trigger UL transmission on band C before T0-Toffset may be applied, where T0 and Toffset are referenced for uplink transmission on band C. As shown in FIG. 6, for this embodiment, T0 is T02 and Toffset is Toffset2. In other words, DCI1 or DCI2 may be used to schedule UL transmission on band C if the UL transmission on band C overlaps with the gap of a UL switch from band A to band B. If there is no UL Tx switch from band A to band B, DCI2 used to trigger UL transmission on band C before T02-Toffset2 may be applied. This exemplary embodiment may be applied to optional UE capabilities and with timeline restrictions based on UL transmission on band C, regardless of the switch from band A to band B.

[0078] In a third optional embodiment, only the DCI used to trigger UL transmission on Band C after T0-Toffset of Band B (and before T0-Toffset of Band C) may apply optional UE capabilities. T0 and Toffset of Band B may be T01 and Toffset1. T0 and Toffset of Band C may be T02 and Toffset2. In other words, DCI1 may not be used to schedule UL transmission on Band C if the UL transmission on Band C overlaps with the gap of UL switching from Band A to Band B. DCI2 may be used to schedule UL transmission on Band C if the UL transmission on Band C overlaps with the gap of UL switching from Band A to Band B. If there is no UL Tx switching from Band A to Band B, DCI2 used to trigger UL transmission on Band C, which may be before T02-Toffset2, can be applied. This exemplary embodiment may relate to the baseline assumption (e.g., FIG. 5a) that overlap between UL transmission on Band C and the switching gaps of Band A and Band B can be supported when UL Tx switching may not be canceled.

[0079] FIG. 7 shows another example uplink (UL) transmission on Band C that is overlapped with the gap in switching between Band A and Band B. FIG. 7 illustrates a fourth optional embodiment in which a DCI used to trigger uplink switching of UL transmission on Band B before T0-Toffset may be applied, where T0 and Toffset are referenced for uplink transmission on Band C. As shown in FIG. 7, T0 is T02 and Toffset is Toffset2. DCI1 may be used to trigger uplink switching of UL transmission on Band B when the UL transmission on Band C overlaps with the gap in UL switching from Band A to Band B. DCI2 may not be used to trigger uplink switching of UL transmission on Band B when the UL transmission on Band C overlaps with the gap in UL switching from Band A to Band B. If there are no UL transmissions on Band C that overlap with the UL switching gap from Band A to Band B, DCI2 may be used to trigger uplink switching of UL transmissions on Band B before T01-Toffset1 may be applied. This embodiment may be applied for optional UE capabilities and with the timeline restriction that DCI is only valid for triggering UL Tx switching of UL transmissions on Band B before T0-Toffset of uplink transmissions on Band C that overlap with the UL Tx switching gap.

[0080] In a fifth optional embodiment, the timeline is from the perspective of UL Tx transmission on Band B rather than Band C. The UE may activate its optional capability for UL Tx on Band B, and this example has a restriction on Band B. A DCI is used to trigger uplink switching of UL transmission on Band B before T0-Toffset may be applied, and T0 and Toffset are referenced for uplink transmission on Band B. As shown in FIG. 7, T0 and Toffset are applied to uplink transmission on Band B and are T01 and Toffset1. DCI1 or DCI2 may be used to trigger uplink switching of UL transmission on Band B if UL transmission on Band C overlaps with the gap for UL switching from Band A to Band B. If there is no UL transmission on Band C that overlaps with the gap for UL switching from Band A to Band B, DCI2 may be used to trigger uplink switching of UL transmission on Band B before T01-Toffset1 may be applied. This exemplary embodiment applies to optional UE capabilities and with timeline restrictions based only on UL transmissions on band B, regardless of UL transmissions on band C.

[0081] In a sixth optional embodiment, the timeline is from the perspective of UL Tx transmission on Band B, not Band C. The DCI used to trigger uplink switching of UL transmission on Band B after T0-Toffset of Band C (and before T0-Toffset of Band B) may apply optional UE capabilities. As shown in FIG. 7 , T0 and Toffset of Band B are T01 and Toffset1. T0 and Toffset of Band C are T02 and Toffset2. DCI1 may not be used to trigger uplink switching of UL transmission on Band B if the UL transmission on Band C overlaps with the gap in UL switching from Band A to Band B. DCI2 may be used to trigger uplink switching of UL transmission on Band B if the UL transmission on Band C overlaps with the gap in UL switching from Band A to Band B. If there are no UL transmissions on Band C that overlap with the UL switching gap from Band A to Band B, DCI2 used to trigger uplink switching of UL transmissions on Band B before T01-Toffset1 may be applied. This exemplary embodiment may be to use the baseline assumption that when UL transmissions on Band C may not be canceled, it overlaps with the UL switching gap from Band A to Band B, and overlap between UL transmissions on Band C and the switching gaps of Band A and Band B can be supported.

[0082] With some timeline constraint for applying optional UE capabilities that support overlap between UL transmission on Band C and the transition gap of Band A and Band B, the UE may have sufficient time to process the optional UE capabilities. It may be beneficial to avoid a lack of time to process the overlap between UL transmission on Band C and the transition gap of Band A and Band B.

[0083] 8a illustrates an embodiment of a user equipment (UE) baseline assumption with simultaneous transmission. Compared to FIG. 5a, FIG. 8a illustrates that band C may have communication during slot n. This may be referred to as simultaneous transmission. Specifically, FIG. 8a illustrates the baseline UE assumption.

[0084] FIG. 8b illustrates an embodiment of user equipment (UE) discretionary capabilities with concurrent transmission. Compared to FIG. 5b, FIG. 8b illustrates that band C may have communication during slot n. This may be referred to as concurrent transmission. Specifically, FIG. 8b illustrates UE discretionary processing capabilities, including communication in band C enabled in slot n+1. The embodiments described below include example timelines for utilizing UE discretionary processing capabilities with concurrent transmission as shown in FIG. 8b.

[0085] Regarding parallel transmissions supported for UL Tx switching, parallel UL transmissions on two different bands may be enabled. A consideration is whether the UL Tx on Band C may overlap with a gap on Band B. Timeline restrictions for operation may be similar to those discussed with respect to Figures 5a-7. The transmission switching option parameter (e.g., uplinkTxSwitchingOption) may be set to "dualUL," also referred to as CA Option 2, meaning that simultaneous transmission between two bands is supported. Under "dualUL" operation, uplink transmissions may be performed on one or two bands before or after switching within the band combination Band A, Band B, and Band C. The switching period is reported for each band pair Band A and Band B, band pair Band B and Band C, and band pair Band A and Band C, respectively, with the same or different values. The switching period is reported for band pair A and B, band pair B and C, and band pair A and C, respectively, with the same or different values, and the switching gap is determined by the larger of the two switching periods if two band pairs are involved in UL Tx switching. A four-band embodiment may also apply. In a dual UL embodiment, there is a Tx switch where 1P+1P on bands A+C is switched to 1P+1P on bands B+C, and 1P transmission on band C may not be expected based on baseline UE assumptions.

[0086] Figure 9 shows an example uplink (UL) transmission on band C overlapping with a switching gap with simultaneous transmission. If an uplink switch is triggered for an uplink transmission start at T0, after T0-Toffset, the UE is not expected to cancel the uplink switch or trigger any other new uplink switch occurring before T0 for any other uplink transmission scheduled after T0-Toffset, where Toffset is the UE processing procedure time (i.e., the UE PUSCH preparation procedure time) defined for the uplink transmission that triggers the switch. For the baseline UE assumption (e.g., Figure 8a), none of the Tx chains are expected to be used for transmission on band C during the switching period. Meanwhile, for optional UE capabilities (e.g., Figure 8b), UL transmission on band C is enabled during the UL switch from bands A+C to B+C, with the number of Tx chains unchanged (i.e., one Tx chain is maintained on the band).

[0087] There may be timeline restrictions to be applied depending on optional UE capabilities (e.g., FIG. 8b). In a first optional embodiment, the DCI used to trigger UL transmission on band C before T0-Toffset can be applied, and T0 and Toffset can be attached to the uplink transmission on band B after the UL Tx switch or where the gap is located. As shown in FIG. 9, T0 is T01 and Toffset is Toffset1. DCI1 may be used to trigger UL transmission on band C if the UL transmission on band C overlaps with the gap in the UL switch from A+C to B+C. DCI2 may not be used to trigger UL transmission on band C if the UL transmission on band C overlaps with the gap in the UL switch from A+C to B+C. If there is no UL Tx switch from A+C to B+C, DCI2 may be used to trigger UL transmission on band C before T02-Toffset2 may be applied. This exemplary embodiment may be applied for optional UE capabilities and with the timeline restriction that DCI is only valid for triggering UL transmission on band C before T0-Toffset of uplink transmission on other bands after UL Tx switching.

[0088] In a second optional embodiment, a DCI may be used to trigger UL transmission on Band C before T0-Toffset may be applied, and T0 and Toffset may be attached to uplink transmission on Band C. As shown in FIG. 9, T0 is T02 and Toffset is Toffset2. DCI1 or DCI2 can be used to trigger UL transmission on Band C if the UL transmission on Band C overlaps with the gap of a UL switch from Band A+C to Band B+C. If there is no UL Tx switch from Band A+C to Band B+C, DCI2 may be used to trigger UL transmission on Band C before T02-Toffset2 may be applied. This exemplary embodiment may be applied to optional UE capabilities and with timeline restrictions based on UL transmission on Band C, regardless of the switch from Band A+C to Band B+C.

[0089] In a third optional embodiment, a DCI used to trigger UL transmission on Band C after T0-Toffset of Band B (and before T0-Toffset of Band C) may apply optional UE capabilities. As shown in FIG. 9, T0 and Toffset of Band B are T01 and Toffset1. T0 and Toffset of Band C are T02 and Toffset2. DCI1 may not be used to schedule UL transmission on Band C if the UL transmission on Band C overlaps with the gap of UL switching from Band A+C to Band B+C. DCI2 may be used to schedule UL transmission on Band C if the UL transmission on Band C overlaps with the gap of UL switching from Band A+C to Band B+C. If there is no UL Tx switching from Band A+C to Band B+C, DCI2 may be used to trigger UL transmission on Band C before T02-Toffset2 may be applied. This exemplary embodiment may be to use the baseline assumption (e.g., FIG. 8a) that overlap between UL transmission on Band C and the switch gap from Bands A+C to Bands B+C can be supported when UL Tx switchover cannot be canceled.

[0090] In a fourth optional embodiment, optional UE capabilities may apply to DCI that may be used to trigger UL transmission on Band C before T0-Toffset. T0 and Toffset refer to earlier / earliest uplink transmissions on Band B and Band C with overlap between UL transmission on Band C and the transition gap located on Band B.

[0091] In a fifth optional embodiment, optional UE capabilities may be used only for switched UL. For a dual UL switching case from 1P+1P on bands A and C to 1P+1P on bands B and C, the switching gap applies for both bands, regardless of whether 1T on band C is changed or not.

[0092] In these embodiments, with some timeline constraint for applying optional UE capabilities that support overlap between UL transmission on band C and the transition gap of bands A and B, the UE may have sufficient time to process the optional UE capabilities. It may be beneficial to avoid a lack of time to process the overlap between UL transmission on band C and the transition gap of bands A and B.

[0093] Figure 10 shows an embodiment with four bands. The switch may be one Tx switch where Bands A+C are switched to Bands B+D, or one Tx switch where Band A is switched to Band B and one Tx switch where Band C is switched to Band D. This embodiment may define one Tx switch that can be implemented in three or four bands. The embodiments described below include timelines where the base station and UE understand that this is a single Tx switch between more than one band.

[0094] When the UE is triggered to perform a TX switch between band pairs and the start of UL transmission after the TX switch is T0, the UE uses the grant received before T0-Toffset to determine how to perform the switch, where Toffset is the UE processing procedure time defined with respect to the uplink transmission trigger. If two Tx chains are triggered to switch between two different band pairs (e.g., from Band A+Band C to Band B+Band D) based on the grant, the UE will perform this as one TX switch involving more than two bands if the condition is met, or as two TX switches otherwise. There may be several embodiment options for implementation.

[0095] In a first optional embodiment, two UL transmissions after a Tx switch are partially overlapped, or the gap between the two UL transmissions is less than a certain value. The gap between two UL transmissions means the end of one UL transmission and the start of the other. The UE may perform one UL Tx switch or two UL Tx switches. As described below, there may be restrictions if there is only one UL Tx switch. If the restrictions are not met, there may be two UL Tx switches.

[0096] Figure 11 shows exemplary uplink (UL) transmissions on four bands with a switching gap. This example may also include an example with less than a switching gap. This is the case when two UL transmissions after a TX switch do not overlap, but the gap is less than the switching gap (e.g., bands B and D do not overlap). When a slot is allowed only one UL Tx switch, the gap between two UL transmissions may be less than the switching gap, similar to the partial overlap case. In an alternative embodiment, the gap is less than the switching gap, and the two UL transmissions may be in the same slot.

[0097] In a second optional embodiment, there may be less than a switching gap, and the two UL transmissions are in different slots. Figure 12 shows another example uplink (UL) transmission on four bands with a switching gap. The two UL transmissions after TX switching may be in the same slot, regardless of the gap size between the two UL transmissions.

[0098] Because the UE may not allow more than one UL Tx switch to occur within one slot, there may be a gap between two UL transmissions after the switch that is larger than the switch gap. This may be considered as one UL TX switch. The gap between two UL transmissions may be less than the switch gap and applies only to the different slot embodiment.

[0099] In a third optional embodiment, the two UL transmissions after the Tx switch may be within one reference slot, which may result in the gap being widened as shown in Figure 12.

[0100] In a fourth optional embodiment, the latest / earliest T0-Toffset is used to determine the deadline for grants to trigger two possible UL transmissions within one reference slot. Since the band pairing from 1P+1P on bands A and C to 1P+1P on bands B and D is unclear, it may not be clear whether the UE will perform Tx switching (band A to C+B to D) or (band A to D+B to C).

[0101] In some embodiments, with some timeline constraints for applying one Tx switch where Bands A+C are switched to Bands B+D, the UE and the base station may have the same understanding of whether the switch is one Tx switch where Bands A+C are switched to Bands B+D, or one Tx switch where Band A is switched to Band B and one Tx switch where Band C is switched to Band D. It may be beneficial to avoid unnecessary switching gaps associated with more than one UL Tx switch.

[0102] In another embodiment, when two Tx chains are switched between two different band pairs with different length switching periods, neither of the two Tx chains is expected to be used for transmission during the larger of the two switching periods. In other words, the switching gap may be determined by the larger of the two switching periods when two band pairs are involved in UL Tx switching.

[0103] For the first embodiment (e.g., 2P on Band A switched to 1P on Band B + 1P on Band C), one of the two Tx chains is triggered to switch from one band (referred to as "Band A") to another band (referred to as "Band B"), and the other Tx chain is triggered to switch from one band (referred to as "Band A") to another band (referred to as "Band C"), and the switching gap for case a is determined by the maximum values ​​{Tswitch_A-B, Tswitch_A-C}. Note: Tswitch_A-B, Tswitch_A-C are the switching periods reported by the UE for band pairs A & B and A & C, respectively.

[0104] For the second embodiment (e.g., 1P on Band A + 1P on Band C is switched to 1P on Band B + 1P on Band D), regardless of whether the UE performs Tx switching {Bands A to C and B to D} or {Bands A to D and B to C}, neither of the two Tx chains is expected to be used for transmission during the maximum of the four switching periods, i.e., maximum {Tswitch_A-C, Tswitch_B-D, Tswitch_A-D, Tswitch_B-C}. Note: Tswitch_A-C, Tswitch_B-D, Tswitch_A-D, Tswitch_B-C are the switching periods reported by the UE for band pairs A and C, B and D, A and D, and B and C, respectively.

[0105] Regarding the third embodiment (e.g., 1P on band A + 1P on band B is switched to 1P on band A + 1P on band C), when a UE is to transmit 1-port + 1-port transmissions on one uplink carrier on different bands (first and second bands), respectively, if the Tx chain state in the preceding uplink transmission is 1T+1T on the carrier on one of the bands and another different band (first or second band, and third band), respectively, the switching gap can be determined by one of the following options: Option 1: Tswitch_B-C, which is the switching period for band pair B and C. In other words, one of the two Tx chains is triggered to switch from one band (called "Band B") to another band (called "Band C"), while the other Tx chain remains unchanged on Band A. The switching gap is determined by Tswitch_B-C, which is the switching period for band pair B and C. In other words, the switching gap for Case C can be determined based on the switching period of the band pair of the other one of the bands and another different band (the second or first band, and the third band). Option 2: Maximum of {Tswitch_A-C, Tswitch_B-A}. In this example, one of the two Tx chains is triggered to switch from one band (called "Band A") to another band (called "Band C"), and the other Tx chain is triggered to switch from a third band (called "Band B") to one band (called "Band A"). Option 3: Maximum of {Tswitch_A-C, Tswitch_B-A, Tswitch_B-C}. In other words, regardless of whether the UE performs Tx switching {Band B to C} or {Band A to C and B to A}, none of the two Tx chains is expected to be used for transmission during the maximum of the three switching periods, i.e., maximum of {Tswitch_A-C, Tswitch_B-A, Tswitch_B-C}.

[0106] Based on this embodiment, when a UE is to transmit 1-port+1-port transmissions on one uplink carrier on different bands (first and second bands), respectively, if the Tx chain state in the preceding uplink transmission is 1T+1T on a carrier on one of the bands and another different band (first or second band, and third band), respectively, the switching gap for the switching case is clear between the base station and the UE; otherwise, the UL transmission after UL Tx switching is available from the perspective of the base station, but can be omitted by the UE if there is an ambiguous understanding about the switching gap between the base station and the UE.

[0107] In another embodiment, in legacy UL Tx switching, the approach to determining the location of the switching period may include configuring one band as the band in which the switching period is located. An exemplary detailed Rel-16 / 17 by cell configuration is shown below. [ka]

[0108] In the example of Rel-18 UL Tx switching, where three or four bands are involved in one uplink switch, the location of the switch period may be determined by one of the following alternatives: Alternative 1: The location of the switchover period is configured per band pair. If there are multiple bands configured with the location of the switchover period as true in the bands involved in the switchover, the location of the switchover period is determined to be the highest carrier frequency of the bands configured with the location of the switchover period as true. Alternative 2: A changeover period location is configured for each band pair, and a priority list of bands is also configured. If there are multiple bands configured with changeover period location as true for the bands involved in the changeover, the changeover period location is determined to be the band with the lowest priority among the bands configured with changeover period location as true. Alternative 3: The base station configures a "switch out of band" or a "switch into band." If the base station configures a "switch out of band" as the location of the switch period, the switch period is located on the band in which the preceding transmission is performed. Alternative 4: The base station configures the location of the switching period for each switching case. In the 3-band case, the gNB configures the location of the switching period for each switching case pair, such as {AB}, {AC}, {BC}, {A+BC}, {A+CB}, {B+CA}, etc. In the 4-band case, the base station configures the location of the switching period for each switching case pair, such as {AB}, {AC}, {AD}, {BC}, {BD}, {CD}, {A+BC}, {A+BD}, {A+CB}, {A+CD}, {A+DB}, {A+DC}, {B+CA}, {B+CD}, {B+DA}, {B+DC}, {C+DA}, {C+DB}, {A+B-C+D}, {A+C-B+D}, {A+D-B+C}}, etc. Alternative 5: The base station configures the location of the switching period for each of the three or four configured bands. In the three-band case, the base station configures the location of the switching period for each switching case pair, such as {A, B}, {A, C}, {B, C}, {A, B, C}, etc. In the four-band case, the gNB configures the location of the switching period for each switching case pair, such as {A, B}, {A, C}, {A, D}, {B, C}, {B, D}, {C, D}, {A, B, C}, {A, B, D}, {B, C, D}, {A, B, C, D}, etc. Alternative 6: The base station configures the priority for each carrier / band. The UE determines the location of the handover period on the band without the highest priority.

[0109] In another embodiment for Alternative 3, if two bands are involved as a switch from or to a band and are configured with the location of the switch period as true, the band with the configured or lowest / highest band index (or carrier index) is selected, or the band (or carrier) with the lowest / highest priority is selected if a priority list of bands (or carriers) is also configured.

[0110] In another embodiment for Alternative 3, the base station configures a "switch from band" or a "switch to band" for each band combination or switch case pair. In this example, this is any switch case in which a switch period should occur. Overall, Alternative 3 may include RRC signaling overhead. If the base station configures a "switch from band" as the location of the switch period, the switch period occurs on a band configured in the band combination where a preceding transmission occurred in the band combination.

[0111] In another embodiment, when a UE performs UL Tx switching, the following restrictions may apply for Rel-18 UL Tx switching across three or four bands: The UE may not expect to perform more than one uplink switch in a reference slot based on μ = max(μ,1, μ,2, μ,3) for three bands and μ = max(μ,1, μ,2, μ,3, μ,4) for four bands, where μ,1, μ,2, μ,3, μ,4 are the SCSs of the active UL bandwidth portions of the bands in the band combination. If there are two consecutive in-band carriers in a band, μ = max(μ,1-1, μ,1-2), where μ and μ are the SCSs of the active UL bandwidth portions of the carriers in the bands.

[0112] The UE may not expect to perform two uplink switches within a minimum separation time, which can be determined by one of the following options:

[0113] Option 1: When two uplink switches are triggered resulting in UL transmissions on more than two bands within any two consecutive reference slots, the duration between the end of all transmissions prior to the first uplink switch and the start of all transmissions after the second uplink switch within the two reference slots is expected to be equal to or greater than the minimum separation time. The minimum separation time is the sum of X μsec and the required switching gap for the second uplink switch. X μsec is an integer value or set of values, subject to UE capabilities. Optionally, X can be 0, 50, 100, 200, 500, or 1,000.

[0114] Option 2: When two uplink switches are triggered resulting in UL transmissions on more than two bands within any two consecutive reference slots, the duration between the end of all transmissions prior to the first uplink switch and the start of all transmissions after the second uplink switch within the two reference slots is expected to be equal to or greater than the minimum separation time. The minimum separation time is X μsec, or the sum of X μsec and the two switching gaps required for the first uplink switch and the second uplink switch as shown in FIG. 13. X μsec is an integer value or set of values, subject to UE capabilities. Optionally, X can be 0, 50, 100, 200, 500, or 1,000.

[0115] Option 3: When two uplink switches are triggered resulting in UL transmissions on more than two bands within any two consecutive reference slots, the duration between the start of all transmissions prior to the second uplink switch and the start of all transmissions after the second uplink switch within the two reference slots is expected to be greater than or equal to the minimum separation time. The minimum separation time is X μsec, or the sum of X μsec and the required switching gap for the second uplink switch as shown in FIG. 14. X μsec is an integer value or set of values, subject to UE capabilities. Optionally, X can be 0, 50, 100, 200, 500, or 1,000.

[0116] Option 4: If two uplink switches are triggered resulting in UL transmissions on more than two bands within any two consecutive reference slots, the duration between the start of all transmissions after the first uplink switch and the start of all transmissions after the second uplink switch within the two reference slots is expected to be equal to or greater than the minimum separation time. The minimum separation time is X μsec, or the sum of X μsec and the required switching gap for the second uplink switch as shown in FIG. 14. X μsec is an integer value or set of values, subject to UE capabilities. Optionally, X can be 0, 50, 100, 200, 500, or 1,000.

[0117] Option 5: When two uplink switches are triggered resulting in UL transmissions on more than two bands within any two consecutive reference slots, the duration between the end of all transmissions after the first uplink switch and the start of all transmissions after the second uplink switch within the two reference slots is expected to be equal to or greater than the minimum separation time. The minimum separation time is X μsec, or the sum of X μsec and the required switching gap for the second uplink switch as shown in FIG. 15. X μsec is an integer value or set of values, subject to UE capabilities. Optionally, X can be 0, 50, 100, 200, 500, or 1,000. Switching for UEs with more than two Tx

[0118] As described above, there may be a limited number of transmitters (Tx). In other embodiments, there may be three or more Tx. For the example described below, there may be three Tx. For example, the Tx capability considered may be 1 Tx in the FDD band and 2 Tx UL MIMO / TxD in the TDD band. In this example, there may be two exemplary switching scenarios. In the first scenario, 1 Tx on TDD is switched to FDD (1 Tx on FDD + 2 Tx on TDD band to 2 Tx on FDD + 1 Tx on TDD band). In another example, 1T+2T is switched to 2T+1T, i.e., from 1P+2P transmission on band A+B to 2P+1P transmission on band A+B. In a second scenario, there may be a switch from 1Tx on FDD to TDD (1Tx on FDD + 2Tx on TDD bands to 0Tx on FDD + 3Tx on TDD bands). In another example, 1T+2T is switched to 0T+3T, i.e., from 1P+2P transmission on bands A+B to 0P+3P transmission on bands A+B.

[0119] In one embodiment, there may be a SUL and CA option in the first scenario. [Table 14]

[0120] One switching embodiment for switched UL may be that 0P+2P is switched to / from 2P+0P. This condition means that "when a UE is to transmit a two-port transmission on one uplink carrier on one band, if the preceding uplink transmission is a two-port transmission on another uplink carrier on another band, the UE shall not transmit N+0P on any of the carriers." Tx1-Tx2 "The term 'not expected to be transmitted for a period of time greater than the specified duration' is used."

[0121] In another embodiment, there may be a second option for the CA in the first scenario. [Table 15]

[0122] There may be four switching embodiments for dual UL (0P+2P / 1P+2P switched to / from 2P+0P / 2P+1P), but one condition may be sufficient to cover all four embodiments: When a UE is to transmit a two-port transmission on one uplink carrier on one band, if the preceding uplink transmission is a two-port transmission on another uplink carrier on another band, the UE may transmit N on any of the carriers. Tx1-Tx2 There may be no ambiguity regarding possible switching scenario 1, where 1 Tx on TDD switches to FDD.

[0123] In another embodiment, there may be a first option for the SUL and CA for the second scenario. [Table 16]

[0124] For the switched UL, in cases where a "1T+2T" or "2T+1T" Tx chain can be assumed, the switched UL may also include an ambiguity issue. Otherwise, there may be no ambiguity issue for the switched UL. The ambiguity issue may include whether the Tx chain is 0T+3T or 1T+2T when 3P+0P is switched to 0P+2P, or whether the Tx chain is 0T+3T, 1T+2T, or 2T+1T when 3P+0P is switched to 0P+1P. For the first ambiguity issue, there may be two states that are sufficient to resolve the ambiguity issue, similar to the current oneT and twoT. For the second ambiguity issue, there may be three states that are required to resolve the ambiguity issue, such as oneT, twoT, and threeT.

[0125] In a switched UL embodiment without ambiguity issues, there may be nine switching embodiments for the switched UL ((0P+3P) / (0P+2P) / (0P+1P) switched to / from (3P+0P) / (2P+0P) / (1P+0P)). One condition may be sufficient to cover the nine example cases. This condition is that when a UE is to transmit a 1-port, 2-port, or 3-port transmission on one uplink carrier on one band, if the preceding uplink transmission is a 1-port, 2-port, or 3-port transmission on another uplink carrier on another band, the UE shall not transmit N on any of the carriers. Tx1-Tx2 The duration of the time period may include not being expected to transmit.

[0126] In an exemplary case of switched UL with ambiguity issues, five conditions may exist. The second and third conditions may be combined in one embodiment. The first condition may cover that (3P+0P) / (2P+0P) / (1P+0P) is switched to 0P+3P, which is not an ambiguity issue. This condition means that when a UE is to transmit a 3-port transmission on one uplink carrier on one band, if the preceding uplink transmission is a 1-port, 2-port, or 3-port transmission on another uplink carrier on another band, the UE may transmit N on any of the carriers. Tx1-Tx2 The duration of the time period may include not being expected to transmit.

[0127] The second condition, combined with the ambiguity issue, may cover (3P+0P) / (2P+0P) / (1P+0P) in a 3T+0T Tx chain being switched to 0P+2P in a 0T+3T or 1T+2T Tx chain. This condition may be combined with the resolution of the ambiguity issue. If a UE is configured with [uplinkTxSwitchingTxState] and then set to "twoToneT" (2T+1T), when the UE is in an operating state where three-port transmission can be supported on one carrier on one band, followed by no transmission on any carrier on the same band and two-port transmission on another carrier on another band, the UE shall regard this as if two-port + one-port transmission was transmitted on both uplinks; otherwise, threeT may refer to 3T. The UE shall regard this as if three-port transmission occurred on the transmission carrier.

[0128] The third condition, combined with the ambiguity issue, would cover (2P+0P) / (1P+0P) in a 2T+1T Tx chain being switched to 0P+2P in a 0T+3T or 1T+2T Tx chain. This condition is combined with the resolution of the ambiguity issue. If the UE is configured with [uplinkTxSwitchingTxState] set to "twoT" (2T+1T), when the UE is in an operating state where a maximum of two-port transmission can be supported on one carrier on one band, followed by no transmission on any carrier on the same band and two-port transmission on another carrier on another band, the UE shall regard this as if two-port + one-port transmissions were transmitted on both uplinks; otherwise, it is "threeT" (3T), and the UE shall regard this as if three-port transmissions occurred on the transmission carriers.

[0129] The fourth condition, combined with the ambiguity issue, may cover (3P+0P) / (2P+0P) / (1P+0P) in a 3T+0T Tx chain being switched to 0P+1P in a 0T+3T, 1T+2T, or 2T+1T Tx chain. This condition may be combined with the resolution of the ambiguity issue. If the UE is configured with [uplinkTxSwitchingTxState] set to "oneT" (1T+2T), when the UE is in an operating state where 3-port transmission may be supported on one carrier on one band followed by no transmission on any carrier on the same band and 1-port transmission on another carrier on another band, the UE shall regard this as if 1-port + 2-port transmission was transmitted on both uplinks; if the UE is configured with [uplinkTxSwitchingTxState] set to "twoT" (2T+1T), when the UE is in an operating state where 3-port transmission may be supported on one carrier on one band followed by no transmission on any carrier on the same band and 2-port transmission on another carrier on another band, the UE shall regard this as if 2-port + 1-port transmission was transmitted on both uplinks; otherwise, "threeT" (3T), the UE shall regard this as if 3-port transmission occurred on the transmitting carriers.

[0130] The fifth condition may cover (2P+0P) / (1P+0P) in a 2T+1T Tx chain being switched to 0P+1P in a 0T+3T or 1T+2T Tx chain, combined with the ambiguity issue, which may be merged into the third condition or considered invalid.

[0131] In another embodiment, there may be a second option for the CA in a second scenario. [Table 17]

[0132] When 3P+0P is switched to 0P+2P, there may be ambiguity as to whether the Tx chain is 0T+3T or 1T+2T; when 3P+0P is switched to 0P+1P, there may be ambiguity as to whether the Tx chain is 0T+3T, 1T+2T, or 2T+1T; when 3P+0P is switched to 0P+1P, there may be ambiguity as to whether the Tx chain is 2T+1T or 1T+2T. Regarding the first and second ambiguity issues, this may be similar to switched UL. Regarding the third ambiguity issue, there may be two conditions for resolving the ambiguity issue, similar to the current oneT and twoT. In a dual UL embodiment, there may be seven conditions. The first five conditions may be the same as switched UL with an additional antenna port for UL transmission. The sixth and seventh conditions may be for dual UL only.

[0133] One condition may cover that (3P+0P) / (2P+0P) / (1P+0P) / (2P+1P) / (1P+1P) / (1P+2P) is switched to 0P+3P without any ambiguity issues. This condition means that when a UE is to transmit a 3-port transmission on one uplink carrier on one band, if the preceding uplink transmission is a 1-port, 2-port, or 3-port transmission on another uplink carrier on another band, the UE shall not transmit N on any of the carriers. Tx1-Tx2 The point is that the signal is not expected to be transmitted for a duration of time.

[0134] The second condition, combined with the ambiguity issue, would cover (3P+0P) / (2P+0P) / (1P+0P) in a 3T+0T Tx chain being switched to 0P+2P in a 0T+3T or 1T+2T Tx chain. This condition is combined with the resolution of the ambiguity issue. If the UE is configured with [uplinkTxSwitchingTxState] set to "twoT" (2T+1T), when the UE is in an operating state where three-port transmission can be supported on one carrier on one band, followed by no transmission on any carrier on the same band and two-port transmission on another carrier on another band, the UE shall regard this as if two-port + one-port transmissions were transmitted on both uplinks; otherwise, it is "threeT" (3T), and the UE may regard this as if three-port transmissions occurred on the transmission carriers.

[0135] The third condition, combined with the ambiguity issue, would cover (2P+0P) / (1P+0P) / (2P+1P) / (1P+1P) / (0P+1P) in a 2T+1T Tx chain being switched to 0P+2P in a 0T+3T or 1T+2T Tx chain. This condition is combined with the resolution of the ambiguity issue. If the UE is configured with [uplinkTxSwitchingTxState] set to "twoT" (2T+1T), when the UE is in an operating state where two-port transmission can be supported on one carrier on one band, followed by no transmission on any carrier on the same band and two-port transmission on another carrier on another band, the UE shall consider this as if two-port + one-port transmissions were transmitted on both uplinks. Otherwise, it is "threeT" (3T), and the UE may consider this as if three-port transmissions occurred on the transmission carriers.

[0136] The fourth condition, combined with the ambiguity problem, would cover (3P+0P) / (2P+0P) / (1P+0P) in a 3T+0T Tx chain being switched to 0P+1P in a 0T+3T, 1T+2T, or 2T+1T Tx chain. This condition is combined with the resolution of the ambiguity problem. If the UE is configured with [uplinkTxSwitchingTxState] set to "oneT" (1T+2T), when the UE is in an operating state where 3-port transmission may be supported on one carrier on one band followed by no transmission on any carrier on the same band and 1-port transmission on another carrier on another band, the UE shall regard this as if 1-port + 2-port transmission was transmitted on both uplinks; if the UE is configured with [uplinkTxSwitchingTxState] set to "twoT" (2T+1T), when the UE is in an operating state where 3-port transmission may be supported on one carrier on one band followed by no transmission on any carrier on the same band and 2-port transmission on another carrier on another band, the UE shall regard this as if 2-port + 1-port transmission was transmitted on both uplinks; otherwise, "threeT" (3T), the UE may regard this as if 3-port transmission occurred on the transmitting carriers.

[0137] The fifth condition, combined with the ambiguity issue, would cover (2P+0P) / (1P+0P) / (2P+1P) / (1P+1P) / (0P+1P) in a 2T+1T Tx chain being switched to 0P+1P in a 0T+3T or 1T+2T Tx chain, which can be considered invalid for dual UL.

[0138] The sixth condition may not have any ambiguity issues, and may cover that (2P+1P) / (2P+0P) / (3P+0P) is switched to 1P+2P. This condition means that when a UE is to transmit a 2-port transmission on one uplink carrier on one band and a 1-port transmission on another uplink carrier on another band, if the preceding uplink transmission is a 2-port or 3-port transmission on another uplink carrier on another band, the UE may not transmit N+2P on any of the carriers. Tx1-Tx2 The duration of the time period may include not being expected to transmit.

[0139] The seventh condition, combined with the ambiguity issue, would cover (3P+0P) / (0P+3P) being switched to 1P+1P. This condition is combined with the resolution of the ambiguity issue. If the UE is configured with [uplinkTxSwitchingTxState] set to "twoToneT" (2T+1T), when the UE is in an operating state where 3-port transmission can be supported on one carrier on one band, followed by 1-port transmission on either carrier on the same band, and there is 1-port transmission on another carrier on another band, the UE shall regard this as if 2-port + 1-port transmission was transmitted on both uplinks; otherwise, it is "oneTtwoT" (1T+2T), and the UE may regard this as if 1-port + 1-port transmission occurred on both uplinks.

[0140] In the embodiments, a 3Tx UE may be assumed, and UL Tx switching using 3Tx on two bands is disclosed. New conditions may be included to implement UL Tx switching for 3Tx scenarios. New ambiguity issues may be identified and resolved by the embodiments. Based on the embodiments, it may be beneficial to implement UL Tx switching using 3Tx.

[0141] The systems and processes described above may be encoded in a signal-bearing medium such as a memory, a computer-readable medium, programmed into one or more integrated circuits, one or more processors, or processed by a controller or computer. The data may be analyzed in a computer system and used to generate a spectrum. If the method is implemented by software, the software may reside in a non-volatile or volatile memory that communicates with a memory, synchronizer, communication interface, or transmitter that resides in or interfaces with a storage device. The circuit or electronic device is designed to transmit the data to another location. The memory may contain an ordered list of executable instructions for implementing a logical function. The described logical function or any system element may be implemented through optical circuitry, digital circuitry, source code, analog circuitry, analog sources such as analog electrical, audio, or video signals, or a combination. The software may be embodied in any computer-readable or signal-bearing medium for use by or in connection with an instruction-executable system, apparatus, or device. Such a system may include a computer-based system, a processor-containing system, or another system that may selectively fetch instructions from an instruction-executable system, apparatus, or device that may also execute the instructions.

[0142] "Computer-readable medium," "machine-readable medium," "propagating signal" medium, and / or "signal-bearing medium" may comprise any device that contains, stores, communicates, propagates, or transports software for use by or in connection with an instruction-executable system, apparatus, or device. Machine-readable media may alternatively be, but are not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. A non-exhaustive list of examples of machine-readable media would include electrically connected "electronic devices" having one or more wires, portable magnetic or optical disks, volatile memory such as random access memory "RAM," read-only memory "ROM," erasable programmable read-only memory (EPROM or flash memory), or optical fibers. Machine-readable media may also include tangible media on which software is printed, so that the software can be stored electronically, as an image or in another format (e.g., through optical scanning), and then compiled and / or interpreted or otherwise processed. The processed media may then be stored in computer and / or machine memory.

[0143] The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may become apparent to those skilled in the art upon review of the present disclosure. Other embodiments may also be utilized and derived from the present disclosure, such that structural and logical substitutions and modifications may be made without departing from the scope of the present disclosure. Additionally, the illustrations are merely representative and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Therefore, the present disclosure and the figures should be considered illustrative, not restrictive.

[0144] One or more embodiments of the present disclosure may be referred to herein, individually and / or collectively, by the term "invention" merely for convenience and without any intention to intentionally limit the scope of the present application to any particular invention or inventive concept. Furthermore, while specific embodiments have been illustrated and described herein, it should be understood that any subsequent arrangements designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. The present disclosure is intended to cover any subsequent adaptations or modifications of the various embodiments. Combinations of the above embodiments and other embodiments not specifically described herein will be apparent to those skilled in the art upon review of the description.

[0145] The phrase "coupled with" is defined to mean directly connected or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware and software-based components. Variations in the arrangement and type of components may be made without departing from the spirit or scope of the claims as set forth herein. Additional, different, or fewer components may be provided.

[0146] The above disclosed subject matter should be considered illustrative, not restrictive, and the appended claims are intended to cover all such modifications, extensions, and other embodiments that fall within the true spirit and scope of the present invention. Accordingly, to the maximum extent permitted by law, the scope of the present invention should be determined by the broadest permissible interpretation of the following claims and their equivalents, and should not be restricted or limited by the foregoing detailed description. While various embodiments of the present invention have been described, it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the present invention. Accordingly, the present invention should not be limited except in light of the appended claims and their equivalents.

Claims

1. 1. A method for wireless communication implemented by a wireless communication device, comprising: receiving an indication of a trigger for an uplink (UL) transmitter (Tx) switch between the two bands; transmitting an UL transmission on a third band during the UL Tx switching; A method comprising:

2. 1. A method for wireless communication implemented by a wireless communication node, comprising: transmitting an indication of a trigger for an uplink (UL) transmitter (Tx) switch between the two bands; triggering an UL transmission on a third band during said UL Tx switching; A method comprising:

3. the two bands comprise a first band and a second band, and the switching is from the first band to the second band; 3. The method of claim 1, wherein the indication comprises a first Downlink Control Information (DCI), and wherein the UL transmission on the third band during the UL Tx switching is triggered by a second DCI.

4. 4. The method of claim 3, wherein the second DCI for triggering the UL transmission on the third band is received before a gap before a start of the UL transmission on the second band after the UL Tx switch.

5. 4. The method of claim 3, wherein the second DCI for triggering the UL transmission on the third band is received after a gap before a start of the UL transmission on the second band.

6. The method of claim 5 , wherein the second DCI for triggering the UL transmission on the third band is before a gap before a start of UL transmission on the third band.

7. 4. The method of claim 3, wherein the first DCI for triggering the UL transmission on the second band is received before a gap before a start of the UL transmission on the third band.

8. 1. A method of wireless communication implemented by a wireless communication device, comprising: receiving a trigger for two uplink (UL) transmit (Tx) chains to switch between two different band pairs; identifying the one-port transmission on one band and the one-port transmission on another band after the switch as a single Tx switch based on a restriction; A method comprising:

9. The method of claim 8 , wherein the restriction includes that the two UL transmissions after the Tx switch are partially overlapped or that the gap between the two UL transmissions is less than a threshold.

10. The method of claim 9 , wherein the gap between the two UL transmissions is less than the threshold and the two UL transmissions are in different slots.

11. The method according to claim 9 or 10, wherein the threshold is a switching gap of the UL Tx switching.

12. The method of claim 8 , wherein the restriction includes the two UL transmissions after the Tx switch being within a reference slot.

13. 1. A method of wireless communication implemented by a wireless communication device, comprising: transmitting up to two uplink (UL) transmissions on a subset of bands from the band combination after a UL transmitter (Tx) switch; establishing conditions for the transmission, wherein 3Tx is supported by the wireless communication device; A method comprising:

14. 14. The method of claim 13, wherein one of the UL transmissions comprises a one-port, two-port, or three-port transmission on one UL carrier on one band of the band combination.

15. 15. The method of claim 14, wherein when the two-port transmission on an UL carrier is on one band after UL Tx switching and a preceding UL transmission with a 3Tx state is on another band, the Tx state after the UL Tx switching is 2Tx or 3Tx on one band according to a parameter with two possible values.

16. 15. The method of claim 14, wherein when the one-port transmission on an UL carrier is on one band after UL Tx switching, and a preceding UL transmission with a 3Tx state is on another band, the Tx state after the UL Tx switching is 1Tx, 2Tx, or 3Tx on one band according to a parameter with three possible values.

17. A wireless communication device comprising a processor and a memory, said processor configured to read code from said memory and to implement a method according to any of claims 1-16.

18. A computer program product having stored thereon a computer readable program medium code which, when executed by a processor, causes the processor to implement a method according to any of claims 1-16.

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