Patent Description:
Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeded five billion and continues to grow quickly. The demand of wireless data traffic is rapidly increasing due to the growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, "note pad" computers, net books, and eBook readers. In order to meet the high growth in mobile data traffic, improvements in radio interface efficiency and allocation of new spectrum is of paramount importance.

<CIT> discloses the power of a signal from a mobile terminal device to base terminal device which is efficiently controlled in a wireless communication system in which a mobile terminal and a base terminal device communicates.

This disclosure provides power control for transmissions from a user equipment in adaptively configured time division duplex (TDD) communication systems.

A user equipment and a method performed by the user equipment are provided by the appended claims.

Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system.

The following documents and standards descriptions are hereby incorporated into the present disclosure as if fully set forth herein: 3GPP TS <NUM> v11. <NUM>, "E-UTRA, Physical channels and modulation" (REF <NUM>); 3GPP TS <NUM> v11. <NUM>, "E-UTRA, Multiplexing and Channel coding" (REF <NUM>); 3GPP TS <NUM> v11. <NUM>, "E-UTRA, Physical Layer Procedures" (REF <NUM>); and 3GPP TS <NUM> v11. <NUM>, "E-UTRA, Radio Resource Control (RRC) Protocol Specification. " (REF <NUM>).

This disclosure relates to the adaptation of communication direction in wireless communication networks that utilize Time Division Duplex (TDD). A wireless communication network includes a DownLink (DL) that conveys signals from transmission points (such as base stations or eNodeBs) to user equipments (UEs). The wireless communication network also includes an UpLink (UL) that conveys signals from UEs to reception points such as eNodeBs.

<FIG> illustrates an example wireless network <NUM> according to this disclosure. The embodiment of the wireless network <NUM> shown in <FIG> is for illustration only.

As shown in <FIG>, the wireless network <NUM> includes an eNodeB (eNB) <NUM>, an eNB <NUM>, and an eNB <NUM>. The eNB <NUM> communicates with the eNB <NUM> and the eNB <NUM>. The eNB <NUM> also communicates with at least one Internet Protocol (IP) network <NUM>, such as the Internet, a proprietary IP network, or other data network.

Depending on the network type, other well-known terms may be used instead of "eNodeB" or "eNB," such as "base station" or "access point. " For the sake of convenience, the terms "eNodeB" and "eNB" are used in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, other well-known terms may be used instead of "user equipment" or "UE," such as "mobile station," "subscriber station," "remote terminal," "wireless terminal," or "user device. " For the sake of convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless equipment that wirelessly accesses an eNB, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).

The eNB <NUM> provides wireless broadband access to the network <NUM> for a first plurality of user equipments (UEs) within a coverage area <NUM> of the eNB <NUM>. The first plurality of UEs includes a UE <NUM>, which may be located in a small business (SB); a UE <NUM>, which may be located in an enterprise (E); a UE <NUM>, which may be located in a WiFi hotspot (HS); a UE <NUM>, which may be located in a first residence (R); a UE <NUM>, which may be located in a second residence (R); and a UE <NUM>, which may be a mobile device (M) like a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB <NUM> provides wireless broadband access to the network <NUM> for a second plurality of UEs within a coverage area <NUM> of the eNB <NUM>. The second plurality of UEs includes the UE <NUM> and the UE <NUM>. In some embodiments, one or more of the eNBs <NUM>-<NUM> may communicate with each other and with the UEs <NUM>-<NUM> using <NUM>, LTE, LTE-A, WiMAX, or other advanced wireless communication techniques.

It should be clearly understood that the coverage areas associated with eNBs, such as the coverage areas <NUM> and <NUM>, may have other shapes, including irregular shapes, depending upon the configuration of the eNBs and variations in the radio environment associated with natural and man-made obstructions.

As described in more detail below, various components of the network <NUM> (such as the eNBs <NUM>-<NUM> and/or the UEs <NUM>-<NUM>) support uplink power control in the network <NUM>, which can utilize TDD.

Although <FIG> illustrates one example of a wireless network <NUM>, various changes may be made to <FIG>. For example, the wireless network <NUM> could include any number of eNBs and any number of UEs in any suitable arrangement. Also, the eNB <NUM> could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network <NUM>. Similarly, each eNB <NUM>-<NUM> could communicate directly with the network <NUM> and provide UEs with direct wireless broadband access to the network <NUM>. Further, the eNB <NUM>, <NUM>, and/or <NUM> could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

<FIG> illustrates an example UE <NUM> according to this disclosure. The embodiment of the UE <NUM> shown in <FIG> is for illustration only, and the other UEs in <FIG> could have the same or similar configuration.

As shown in <FIG>, the UE <NUM> includes an antenna <NUM>, a radio frequency (RF) transceiver <NUM>, transmit (TX) processing circuitry <NUM>, a microphone <NUM>, and receive (RX) processing circuitry <NUM>. The UE <NUM> also includes a speaker <NUM>, a main processor <NUM>, an input/output (I/O) interface (IF) <NUM>, a keypad <NUM>, a display <NUM>, and a memory <NUM>. The memory <NUM> includes a basic operating system (OS) program <NUM> and one or more applications <NUM>.

The RF transceiver <NUM> receives, from the antenna <NUM>, an incoming RF signal transmitted by an eNB or another UE. The RX processing circuitry <NUM> transmits the processed baseband signal to the speaker <NUM> (such as for voice data) or to the main processor <NUM> for further processing (such as for web browsing data).

The TX processing circuitry <NUM> receives analog or digital voice data from the microphone <NUM> or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the main processor <NUM>.

The main processor <NUM> can include one or more processors or other processing devices and can execute the basic OS program <NUM> stored in the memory <NUM> in order to control the overall operation of the UE <NUM>. For example, the main processor <NUM> could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver <NUM>, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. In some embodiments, the main processor <NUM> includes at least one microprocessor or microcontroller.

The main processor <NUM> is also capable of executing other processes and programs resident in the memory <NUM>. The main processor <NUM> can move data into or out of the memory <NUM> as required by an executing process such as operations supporting uplink power control in adaptively configured time division duplex (TDD) communication systems. In some embodiments, the main processor <NUM> is configured to execute the applications <NUM> based on the OS program <NUM> or in response to signals received from eNBs, other UEs, or an operator. The main processor <NUM> is also coupled to the I/O interface <NUM>, which provides the UE <NUM> with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface <NUM> is the communication path between these accessories and the main processor <NUM>.

The main processor <NUM> is also coupled to the keypad <NUM> and the display unit <NUM>. The operator of the UE <NUM> can use the keypad <NUM> to enter data into the UE <NUM>. The display <NUM> may be a liquid crystal display or other display capable of rendering text and/or at least limited graphics, such as from web sites. The display <NUM> could also represent a touchscreen.

The memory <NUM> is coupled to the main processor <NUM>.

As described in more detail below, the transmit and receive paths of the UE <NUM> (implemented using the RF transceiver <NUM>, TX processing circuitry <NUM>, and/or RX processing circuitry <NUM>) support downlink signaling for uplink and downlink adaptation in adaptively configured TDD systems.

As a particular example, the main processor <NUM> could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In addition, various components in <FIG> could be replicated, such as when different RF components are used to communicate with the eNBs <NUM>-<NUM> and with other UEs.

<FIG> illustrates an example eNB <NUM> according to this disclosure, not forming part of the claimed invention. The embodiment of the eNB <NUM> shown in <FIG> is for illustration only, and other eNBs of <FIG> could have the same or similar configuration. However, eNBs come in a wide variety of configurations, and <FIG> does not limit the scope of this disclosure to any particular implementation of an eNB.

As shown in <FIG>, the eNB <NUM> includes multiple antennas 305a-305n, multiple RF transceivers 310a-310n, transmit (TX) processing circuitry <NUM>, and receive (RX) processing circuitry <NUM>. The eNB <NUM> also includes a controller/processor <NUM>, a memory <NUM>, and a backhaul or network interface <NUM>.

The RF transceivers 310a-310n receive, from the antennas 305a-305n, incoming RF signals, such as signals transmitted by UEs or other eNBs. The RF transceivers 310a-310n down-convert the incoming RF signals to generate IF or baseband signals. The RX processing circuitry <NUM> transmits the processed baseband signals to the controller/ processor <NUM> for further processing.

The RF transceivers 310a-310n receive the outgoing processed baseband or IF signals from the TX processing circuitry <NUM> and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 305a-305n.

The controller/processor <NUM> can include one or more processors or other processing devices that control the overall operation of the eNB <NUM>. For example, the controller/processor <NUM> could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 310a-310n, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. The controller/processor <NUM> could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor <NUM> could support beam forming or directional routing operations in which outgoing signals from multiple antennas 305a-305n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the eNB <NUM> by the controller/processor <NUM>. In some embodiments, the controller/ processor <NUM> includes at least one microprocessor or microcontroller.

The controller/processor <NUM> is also capable of executing programs and other processes resident in the memory <NUM>, such as a basic OS and operations supporting uplink power control in adaptively configured time division duplex (TDD) communication systems.

The backhaul or network interface <NUM> allows the eNB <NUM> to communicate with other devices or systems over a backhaul connection or over a network. For example, when the eNB <NUM> is implemented as part of a cellular communication system (such as one supporting <NUM>, LTE, or LTE-A), the interface <NUM> could allow the eNB <NUM> to communicate with other eNBs over a wired or wireless backhaul connection. When the eNB <NUM> is implemented as an access point, the interface <NUM> could allow the eNB <NUM> to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet).

As described in more detail below, the transmit and receive paths of the eNB <NUM> (implemented using the RF transceivers 310a-310n, TX processing circuitry <NUM>, and/or RX processing circuitry <NUM>) support downlink signaling for uplink and downlink adaptation in adaptively configured TDD systems.

Although <FIG> illustrates one example of an eNB <NUM>, various changes may be made to <FIG>. For example, the eNB <NUM> could include any number of each component shown in <FIG>. As another particular example, while shown as including a single instance of TX processing circuitry <NUM> and a single instance of RX processing circuitry <NUM>, the eNB <NUM> could include multiple instances of each (such as one per RF transceiver).

In some wireless networks, DL signals include data signals conveying information content, control signals conveying DL Control Information (DCI), and Reference Signals (RS), that are also known as pilot signals. An eNB, such as eNB <NUM>, transmits data information through respective Physical DL Shared CHannels (PDSCHs). eNB <NUM> transmits DCI over Physical DL Control CHannels (PDCCHs) or Enhanced PDCCHs (EPDCCHs). A PDCCH is transmitted over one or more Control Channel Elements (CCEs) while an EPDCCH is transmitted over ECCEs (see also REF <NUM>). An eNB, such as eNB <NUM>, transmits one or more of multiple types of RS including a UE-Common RS (CRS), a Channel State Information RS (CSI-RS), and a DeModulation RS (DMRS). A CRS is effectively transmitted over an entire DL BandWidth (BW) and can be used by UEs, such as UE <NUM>, to demodulate PDSCH or PDCCH, or to perform measurements. eNB <NUM> also can transmit CSI-RS with a smaller density in the time and/or frequency domain than a CRS. For channel measurement, Non-Zero Power CSI-RS (NZP CSI-RS) resources can be used. For interference measurement, UE <NUM> can use CSI Interference Measurement (CSI-IM) resources associated with a Zero Power CSI-RS (ZP CSI-RS) that is configured to the UE by eNB <NUM> using higher layer signaling (see also REF <NUM> and REF <NUM>). DMRS is transmitted only in a BW of a respective PDSCH or PDCCH and UE <NUM> can use a DMRS to coherently demodulate information in a PDSCH or EPDCCH (see also REF <NUM>).

In some wireless networks, UL signals can include data signals conveying information content, control signals conveying UL Control Information (UCI), and RS. UE <NUM> transmits data information or UCI through a respective Physical UL Shared CHannel (PUSCH) or a Physical UL Control CHannel (PUCCH). If UE <NUM> transmits data information and UCI in a same Transmission Time Interval (TTI), UE <NUM> can multiplex both in a PUSCH. UCI includes Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) information, indicating correct (ACK) or incorrect (NACK) detection of data Transport Blocks (TBs) in a PDSCH, Scheduling Request (SR) indicating whether UE <NUM> has data in its buffer, and Channel State Information (CSI) enabling eNB <NUM> to select appropriate parameters for PDSCH or PDCCH transmissions to UE <NUM>. If UE <NUM> fails to detect a PDCCH scheduling a PDSCH, UE <NUM> can indicate this using a HARQ-ACK state referred to as DTX. A DTX and a NACK can often be mapped on a same value (NACK/DTX value, see also REF <NUM>). UL RS includes DMRS and Sounding RS (SRS). DMRS is transmitted only in a BW of a respective PUSCH or PUCCH. eNB <NUM> can use a DMRS for coherent demodulation of information in a PUSCH or PUCCH. SRS is transmitted by UE <NUM> to provide eNB <NUM> with an UL CSI.

SRS transmission from a UE can be periodic (P-SRS) at predetermined TTIs with transmission parameters configured to UE <NUM> by higher layer signaling, such as for example Radio Resource Control (RRC) signaling, or it can be aperiodic (A-SRS) as triggered by a DCI format conveyed by a PDCCH or EPDCCH scheduling PUSCH or PDSCH. In all following descriptions, unless otherwise noted, a parameter is referred to as determined by configuration if its value is provided by higher layer signaling, such as RRC, while is referred to as dynamically determined if its value is provided by a DCI format conveyed in a PDCCH or EPDCCH.

<FIG> illustrates an example PUSCH transmission structure over a TTI according to this disclosure, not forming part of the claimed invention. The embodiment of the PUSCH transmission structure <NUM> over a TTI shown in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

As shown in <FIG>, a TTI corresponds to one subframe <NUM> that includes two slots. Each slot <NUM> includes <MAT> symbols <NUM> for transmitting data information, UCI, or RS. Some TTI symbols in each slot are used for transmitting DMRS <NUM>. A transmission BW includes frequency resource units that are referred to as Resource Blocks (RBs). Each RB includes <MAT> sub-carriers, or Resource Elements (Res), and UE <NUM> is allocated MPUSCH RBs <NUM> for a total of <MAT> Res for a PUSCH transmission BW. The last TTI symbol may be used to multiplex SRS transmissions <NUM> from one or more Ues. A number of TTI symbols available for data/UCI/DMRS transmission is <MAT>, where NSRS=<NUM> if a last TTI symbol is used to transmit SRS and NSRS=<NUM> otherwise.

<FIG> illustrates an example UE transmitter structure for data information and UCI in a PUSCH according to this disclosure, not forming part of the claimed invention. The embodiment of the UE transmitter <NUM> shown in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. In certain embodiments, transmitter <NUM> is located within UE <NUM>.

As shown in <FIG>, coded and modulated CSI symbols <NUM> and coded and modulated data symbols <NUM> are multiplexed by multiplexer <NUM>. Coded and modulated HARQ-ACK symbols are then inserted by multiplexer <NUM> by puncturing data symbols and/or CSI symbols. A transmission of RI is similar to one for HARQ-ACK (not shown). The Discrete Fourier Transform (DFT) is obtained by DFT unit <NUM>, REs <NUM> corresponding to a PUSCH transmission BW are selected by selector <NUM>, an Inverse Fast Fourier Transform (IFFT) is performed by IFFT unit <NUM>, an output is filtered and by filter <NUM> and applied a certain power by Power Amplifier (PA) <NUM> and a signal is then transmitted <NUM>. For brevity, additional transmitter circuitry such as digital-to-analog converter, filters, amplifiers, and transmitter antennas as well as encoders and modulators for data symbols and UCI symbols are omitted for brevity.

<FIG> illustrates an example eNB receiver structure for data information and UCI in a PUSCH according to this disclosure, not forming part of the claimed invention. The embodiment of the eNB receiver <NUM> shown in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. In certain embodiments, eNB receiver <NUM> is located within eNB <NUM>.

As shown in <FIG>, a received signal <NUM> is filtered by filter <NUM>, a Fast Fourier Transform (FFT) is applied by FFT unit <NUM>, a selector unit <NUM> selects REs <NUM> used by a transmitter, an Inverse DFT (IDFT) unit applies an IDFT <NUM>, a de-multiplexer <NUM> extracts coded HARQ-ACK symbols and places erasures in corresponding REs for data symbols and CSI symbols and finally another de-multiplexer <NUM> separates coded data symbols <NUM> and coded CSI symbols <NUM>. A reception of coded RI symbols is similar to one for coded HARQ-ACK symbols (not shown). Additional receiver circuitry such as a channel estimator, demodulators and decoders for data and UCI symbols are not shown for brevity.

Assuming for simplicity a transmission of one data TB in a PUSCH, UE <NUM> determines a number of coded modulation symbols per layer Q' for HARQ-ACK transmission as in Equation <NUM> (see also REF <NUM>) <MAT> where ┌ ┐ is the ceiling function rounding a number to its next integer, O is a number of HARQ-ACK information bits, <MAT> is a PUSCH transmission BW in the current TTI for the data TB, <MAT> is the number of TTI symbols for initial PUSCH transmission for the same data TB, <MAT> is a value configured to the UE from eNB <NUM> by higher layer signaling, <MAT> is a PUSCH transmission BW for initial PUSCH transmission for the same data TB, C is a number of code blocks, and Kr is a number of bits for code block number r. When a PUSCH contains only CSI, in addition to HARQ-ACK, the UE determines a number of coded modulation symbols per layer Q' for HARQ-ACK as <MAT>, where OCSI_MIN is a minimum number of CSI information bits including Cyclic Redundancy Check (CRC) bits. A same determination for a number of coded modulation symbols per layer Q' applies for a transmission of RI with <MAT> replaced by <MAT>. For CSI, a number of coded modulation symbols per layer is determined as Q' as <MAT> where O is a number of CSI bits, L is a number of CRC bits given by <MAT>, and Qm is the number of information bits per modulation symbol. If RI is not transmitted then <MAT>. An encoding process for HARQ-ACK bits, or RI bits, or CSI bits is not discussed as it is not material to this disclosure (see REF <NUM>).

In Equation <NUM>, the parameter <MAT> for a respective UCI type serves for decoupling a BLock Error Rate (BLER) for a data TB from a BLER for the UCI type as it is inversely proportional to a spectral efficiency of data TB transmission. For example, for a given Signal to Noise and Interference Ratio (SINR), eNB <NUM> scheduler can use a larger spectral efficiency for a data TB transmission, leading to a larger BLER operating point for the data TB, but can maintain a fixed BLER for a UCI type by increasing a respective value of <MAT> which will then increase a number of REs allocated to UCI for multiplexing in a PUSCH.

A DMRS or SRS transmission can be through a transmission of a respective Zadoff-Chu (ZC) sequence. For a UL system BW of <MAT> RBs, a sequence <MAT> can be defined by a Cyclic Shift (CS) of a base sequence according to <MAT>, where <MAT> is a sequence length, <NUM>≤m≤ <MAT>, and <MAT> where the qth root ZC sequence is defined by <MAT> with q given by <MAT> and q given by <MAT>. A length <MAT> of a ZC sequence is given by a largest prime number such that <MAT> (see also REF <NUM>). Multiple ZC sequences can be defined from a single base sequence using different values of α. A DMRS transmission in two or more symbols of a TTI, as in <FIG>, can also be modulated with an Orthogonal Covering Code (OCC). For a DMRS transmission in a PUSCH scheduled by PDCCH, UE <NUM> determines a respective ZC sequence from a system information or from a configuration by higher layer signaling and determines a CS and an OCC from a respective CS and OCC index field included in a DCI format scheduling the PUSCH transmission.

<FIG> illustrates an example transmitter structure for a ZC sequence that can be used as DMRS or as SRS according to this disclosure. The embodiment of the transmitter <NUM> shown in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. In certain embodiments, the transmitter <NUM> is located within UE <NUM>.

As shown in <FIG>, a mapper <NUM> maps a ZC sequence of length <MAT> <NUM> to REs of a transmission BW as they are indicated by RE selection unit <NUM>. The mapping can be to consecutive REs for a DMRS or to alternate REs for a SRS thereby creating a comb spectrum (see also REF <NUM>). Subsequently, an IFFT is performed by IFFT unit <NUM>, a CS is applied to the output by CS unit <NUM>, a resulting signal is filtered by filter <NUM>, a transmission power is applied by power amplifier <NUM>, and the RS is transmitted <NUM>.

A PUSCH transmission power is determined so that an associated signal is received with a desired SINR at eNB <NUM> while controlling a respective interference to neighboring cells thereby achieving a reception reliability target and ensuring proper network operation. UL Power Control (PC) includes Open-Loop Power Control (OLPC) with cell-specific and UE-specific parameters and Closed Loop Power Control (CLPC) corrections provided by eNB <NUM> through Transmission Power Control (TPC) commands. If a PUSCH transmission is scheduled by a PDCCH, a TPC command is included in a respective DCI format. TPC commands can also be provided by a separate PDCCH conveying a DCI format <NUM> or a DCI format 3A, jointly referred to as DCI format <NUM>/3A, providing TPC commands to a group of UEs. A DCI format includes Cyclic Redundancy Check (CRC) bits and the UE <NUM> identifies a DCI format type from a respective Radio Network Temporary Identifier (RNTI) used to scramble the CRC bits. For DCI format <NUM>/3A, a RNTI is a TPC-RNTI the UE <NUM> is configured by higher layer signaling. For a DCI format scheduling a PUSCH transmission from the UE <NUM> or a PDSCH transmission to the UE <NUM>, a RNTI is a Cell RNTI (C-RNTI). Additional RNTI types also exist (see also REF <NUM>).

The UE <NUM> can derive a PUSCH transmission power PPUSCH,c(i), in deciBels per milliwatt (dBm), in a cell c during TTI i as in Equation <NUM>. For simplicity, it is assumed that the UE does not transmit both PUSCH and PUCCH in a same TTI (see also REF <NUM>). <MAT> where PCMAX,c(i) is a maximum UE transmit power configured to the UE <NUM> by higher layer signaling, MPUSCH,c(i) is a PUSCH transmission BW in RBs, PO_PUSCH,c(j) controls a mean received SINR at the eNB <NUM> and is the sum of a cell-specific component PO_NOMINAL_PUSCH,c(j) and a UE-specific component PO_UE_PUSCH,c(j) provided to the UE <NUM> by higher layer signaling. For Semi-Persistently Scheduled (SPS) PUSCH, j=<NUM>. For dynamically scheduled PUSCH, j=<NUM>. PLc is a Path Loss (PL) estimate computed by the UE <NUM>. For j=<NUM> or j=<NUM>, αc(j) ∈ {<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>} is configured to the UE <NUM> by higher layer signaling. Fractional UL PC is obtained for αc(j)<<NUM> as a PL is not fully compensated. ΔTF,c(i) is either equal to <NUM> or is determined by a spectral efficiency of a PUSCH transmission. Further details are not material to the present invention and are omitted. Finally, fc(i) = fc(i-<NUM>)+δPUSCH,c(i-KPUSCH) if accumulative CLPC is used, and fc(i) = δPUSCH,c(i-KPUSCH) if absolute CLPC is used where δPUSCH,c(i-KPUSCH) is a TPC command included in a DCI format scheduling a PUSCH or included in a DCI format <NUM>/3A. KPUSCH is derived from a timeline between a TTI of a PDCCH transmission scheduling a PUSCH and a TTI of a respective PUSCH transmission.

A power of a SRS PSRS,c(i) in cell c during TTI i follows a PUSCH transmission power as in Equation <NUM> (see also REF <NUM>) <MAT> where PSRS_OFFSET,c(m) is a <NUM>-bit parameter configured to the UE <NUM> by higher layer signaling, with m = <NUM> for P-SRS and m = <NUM> for A-SRS, and MSRS,c is a SRS transmission BW expressed in number of RBs.

A power for a PUCCH transmission follows similar principles as a power for a PUSCH transmission or SRS transmission (see also REF <NUM>) but, as it is not relevant to this disclosure, further discussion is omitted for brevity.

In a TDD communication system, a communication direction in some TTIs is in the DL, and a communication direction in some other TTIs is in the UL. Table <NUM> lists indicative UL-DL configurations over a period of <NUM> TTIs (a TTI, or subframe (SF), has a duration of <NUM> millisecond (msec)), which is also referred to as frame period. "D" denotes a DL TTI, "U" denotes a UL TTI, and "S" denotes a special TTI that includes a DL transmission field referred to as DwPTS, a Guard Period (GP), and a UL transmission field referred to as UpPTS. Several combinations exist for a duration of each field in a special TTI subject to the condition that the total duration is one TTI.

The TDD UL-DL configurations in Table <NUM> provide <NUM>% and <NUM>% of DL TTIs per frame to be DL TTIs (and the remaining to be UL TTIs). Despite this flexibility, a semi-static TDD UL-DL configuration that can be updated every <NUM> msec or less frequently by signaling of a System Information Block (SIB) or, in case of DL Carrier Aggregation and a secondary cell by RRC signaling (see also REF3 and REF <NUM>), may not match well with short-term data traffic conditions. For the remaining of this disclosure, such a TDD UL-DL configuration will be referred to as a conventional (or non-adapted) TDD UL-DL configuration and it is assumed to be used by conventional (or legacy) UEs in a cell. For this reason, a faster adaptation period of a TDD UL-DL configuration can improve system throughput, particularly for a low or moderate number of connected UEs in a cell. For example, when there is more DL traffic than UL traffic, a conventional TDD UL-DL configuration can be adapted every <NUM>, <NUM>, <NUM>, or <NUM> msec to include more DL TTIs. Signaling for faster adaptation of a TDD UL-DL configuration can in principle be provided by several mechanisms, including signaling of a DCI format in a PDCCH.

An operating constraint in an adaptation of a TDD UL-DL configuration in ways other than conventional ones is the possible existence of UEs that cannot be aware of such adaptation. Such UEs are referred to as conventional UEs. Since conventional UEs perform measurements in DL TTIs using a respective CRS, such DL TTIs cannot be changed to UL TTIs or to special TTIs by a faster adaptation of a TDD UL-DL configuration. However, an UL TTI can be changed to a DL TTI without impacting conventional UEs because the eNB <NUM> can ensure that such UEs do not transmit any signals in such UL TTIs. In addition, an UL TTI common to all TDD UL-DL configurations could exist to enable the eNB <NUM> to possibly select this UL TTI as the only UL one. In some implementations, including all TDD UL-DL configurations in Table <NUM>, this UL TTI is TTI#<NUM>.

A DL TTI is a fixed one if it is a DL TTI in a conventional TDD UL-DL configuration. A special TTI can only switch to a DL TTI. With respect to the descriptions of this disclosure, the only UL fixed TTI is TTI#<NUM>. In general, UL TTIs of a TDD UL-DL configuration that is configured by the eNB <NUM> to the UE <NUM> and can be used by the UE for HARQ-ACK signal transmissions are fixed UL TTIs. A TTI is referred to as DL flexible TTI if it is an UL TTI in a conventional TDD UL-DL configuration and is adapted to a DL TTI. A TTI is referred to as UL flexible TTI if it is an UL TTI in a conventional TDD UL-DL configuration that, although it can be adapted to a DL TTI in an adapted TDD UL-DL configuration, it remains an UL TTI.

Considering the above, Table <NUM> indicates a maximum number of flexible TTIs (denoted by 'F') for each TDD UL-DL configuration in Table <NUM>. Evidently, as DL TTIs in a conventional TDD UL-DL configuration cannot be changed to UL TTIs, not all TDD UL-DL configurations can be used for adaptation. For example, if TDD UL-DL configuration <NUM> is the conventional one, an adaptation can be only to TDD UL-DL configuration <NUM>. Also, a use of a configured TDD UL-DL configuration for UE <NUM> to derive UL TTIs for HARQ-ACK transmissions further restricts TDD UL-DL configuration that can be used for adaptation as such UL TTIs are UL fixed TTIs. Therefore, an indication for an adaptation for a TDD UL-DL configuration can be considered by the UE <NUM> as invalid if, for example, it switches a DL TTI in the conventional TDD UL-DL configuration in an UL TTI. Invalid indications can be caused, by example, by the misdetection from the UE <NUM> of a DCI format conveying an indication for an adapted TDD UL-DL configuration.

A power of an UL transmission in an UL flexible TTI can be different than in an UL fixed TTI as interference in the former may be from a combination of DL transmissions or UL transmissions in adjacent cells while interference in the latter is always from UL transmissions in adjacent cells. Two separate UL PC processes can be considered; one for use in fixed TTIs, such as TTI#<NUM>, and another for use in flexible TTIs. Each UL PC process can have separate OLPC processes through respective values of PO_PUSCH,c(j) and αc(j) or can have separate CLPC processes through separate application of TPC commands δPUSCH,c. However, a conventional approach of having a single UL PC process for flexible TTIs may not be sufficient as different flexible TTIs can experience different interference characteristics. Moreover, having a same UL PC process for all UEs in a cell may also not be sufficient as different UEs can experience different interference.

<FIG> illustrates an example of different interference characteristics in different UL flexible TTIs according to this disclosure. The embodiments of the interference characteristics shown in different flexible TTIs shown in <FIG> are for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

As shown in <FIG>, TDD UL-DL configuration <NUM> is used in reference cell#<NUM><NUM>, TDD UL-DL configuration <NUM> is used in interfering cell#<NUM><NUM>, and TDD UL-DL configuration <NUM> is used in interfering cell#<NUM><NUM>. In fixed TTI#<NUM> in cell#<NUM><NUM>, cell#<NUM><NUM>, and cell#<NUM><NUM>, an interference experienced by UL transmissions is statistically same and a conventional UL PC process can apply. In flexible TTI#<NUM> in cell#<NUM><NUM>, an interference experienced by UL transmissions is different than in fixed TTI#<NUM> as flexible TTI#<NUM> is used for DL transmissions in cell#<NUM><NUM> and for UL transmissions in cell#<NUM><NUM>. Therefore, the UE <NUM> in cell#<NUM> that is located towards cell#<NUM> can experience significantly different interference in TTI#<NUM> than in TTI#<NUM>. In flexible TTI#<NUM> in cell#<NUM><NUM>, an interference experienced by UL transmissions is different than in fixed TTI#<NUM>, or flexible TTI#<NUM>, as flexible TTI#<NUM> is an UL TTI in cell#<NUM><NUM> while it is a DL TTI in cell#<NUM><NUM>. Therefore, UL transmissions from the UE <NUM> in cell#<NUM> that is located towards cell#<NUM> can experience significantly different interference in TTI#<NUM> than in TTI#<NUM> or in TTI#<NUM>. Finally, in flexible TTI#<NUM> in cell#<NUM><NUM>, an interference experienced by UL transmissions can be different than in fixed TTI#<NUM>, or in flexible TTI#<NUM>, or in flexible TTI#<NUM>, as flexible TTI#<NUM> is a DL TTI in both cell#<NUM><NUM> and cell#<NUM><NUM>. Therefore, not only there exists interference variation between the two TTI types (fixed and flexible) but also there exists interference variation in different flexible TTIs.

A consequence of larger interference variations in an UL flexible TTI relative to a UL fixed TTI is that a reception reliability of data TBs transmitted in a PUSCH in a flexible UL TTI can be worse than the one of data TBs transmitted in a PUSCH is a UL fixed TTI. In general, a reception reliability of data TBs in a PUSCH can be worse when the interference in a respective TTI in a DL one than when it is an UL one. This is not a serious issue for transmissions of data TBs, as they can benefit from HARQ retransmissions, but it is a serious issue for UCI transmissions in a PUSCH that have stricter reliability requirements and cannot benefit for HARQ retransmissions.

Embodiments of this disclosure provide mechanisms for associating a first UL PC process and a second UL PC process with a first set of TTIs and with a second set of TTIs in a frame, respectively, in a UE-specific manner where an UL flexible TTI, that is an UL TTI other than TTI#<NUM>, can be associated with either the first UL PC process or the second UL PC process. Embodiments of this disclosure provide TPC commands by DCI format <NUM>/3A for signal transmissions from UE <NUM> in a first set of TTIs and in a second set of TTIs. Embodiments of this disclosure also provide mechanisms for supporting an UL PC process in a second set of TTIs after an adaptation of a TDD UL-DL configuration. Furthermore, embodiments of this disclosure provide mechanisms to enable a reception reliability for data TBs or CSI in a PUSCH UE <NUM> transmits in an UL flexible TTI that is comparable to a reception reliability for data TBs or CSI in a PUSCH UE <NUM> transmits in an UL fixed TTI. Additionally, embodiment of this disclosure provide mechanisms for transmitting and receiving a retransmission of a data transport block in a TTI associated with a first (or second) UL PC process for an initial transmission of the data transport block in a TTI associated with a second (or first) UL PC process.

Adaptation of OLPC and CLPC Parameters in UL Flexible TTIs In certain embodiments, since values of OLPC parameters such as PO_PUSCH,c(j) or αc(j), or CLPC parameters such as fc(i), the UE <NUM> uses for UL signal transmissions can depend on the UE <NUM> location within a cell, an adaptation of such values may not only depend on whether an UL TTI is fixed one or a flexible one but rather it can also depend on a particular UL flexible TTI. A same UL PC process as for an UL fixed TTI, such as TTI#<NUM> in Table <NUM>, can be used in a first UL flexible TTI while a different UL PC process than for an UL fixed TTI can be used in a second UL flexible TTI. Moreover, an adaptation for values of OLPC or CLPC parameters for each UL PC process is UE-specific as an interference experienced by an UL signal transmission can be different for different UEs in a same UL flexible TTI. For UL signal transmissions in a same UL flexible TTI, a first UE <NUM> can use a same UL PC process as in an UL fixed TTI while a second UE <NUM> can use a different UL PC process than in an UL fixed TTI.

As the UE <NUM> typically experiences dominant interference from one adjacent cell, an UL PC process in an UL flexible TTI can be same as for an UL fixed TTI if the flexible TTI in a dominant interfering cell is also an UL TTI. Conversely, an UL PC process in an UL flexible TTI can be different than for an UL fixed TTI if the UL flexible TTI in a dominant interfering cell is a DL TTI. Therefore, an UL PC process for a PUSCH or an A-SRS transmission in an UL flexible TTI can be indicated to the UE <NUM> to be either same as one for an UL fixed TTI (TTI#<NUM> for the TDD UL-DL configurations in Table <NUM>) or different than one in an UL fixed TTI. Therefore, two sets of UL TTIs are determined according to a respective UL PC process for PUSCH or A-SRS transmission; a first set that includes TTI#<NUM> where a first, conventional, UL PC process is used and a second set where a second UL PC process is used. Each UL PC process can be associated with different values of PO_PUSCH,c(j) or αc(j) for OLPC or with different CLPC loops fc(i) which can be configured to the UE <NUM> in advance through higher layer signaling and do not need to be adapted at a same rate as an adaptation of a TDD UL-DL configuration. For A-SRS transmission, PSRS_OFFSET,c(m) can also be configured separately for each UL PC process for respective OLPC. An indication to the UE <NUM> to use a first UL PC process or a second UL PC process in an UL flexible TTI is configured by RRC signaling and, when possible, the RRC configuration can be supplemented by dynamic indication provided by a DCI format in a PDCCH or EPDCCH that schedules a PUSCH or A-SRS transmission.

In a first approach for dynamic indication, an indication for the UE <NUM> to use a first set of values or a second set of values for OLPC or CLPC parameters for UL signal transmission in an UL TTI (other than TTI#<NUM>) is provided by including an additional Power Control Configuration (PCC) field, having one binary element, in DCI formats scheduling PUSCH transmissions. For PUSCH scheduling in UL fixed TTI#<NUM> where a first set of values for OLPC or CLPC parameters is assumed to always be used, the PCC field can be set to a default value, such as '<NUM>'. An exception can be when an A-SRS transmission is also triggered to occur in an UL flexible TTI in which case the PCC field can be interpreted as indicating a set of values for OLPC or CLPC parameters applicable to the A-SRS transmission in the UL flexible TTI.

<FIG> illustrates an example use of a PCC field in a DCI format for associating a respective PUSCH transmission with a first UL PC process or with a second UL PC process according to this disclosure. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the UE <NUM> detects a PDCCH conveying a DCI format scheduling a PUSCH in an UL TTI in operation <NUM>. The UE <NUM> examines a value of a <NUM>-bit PCC field included in the DCI format in operation <NUM>. If this value is a binary '<NUM>', the UE <NUM> transmits a PUSCH with a transmission power determined according to a first set of values for OLPC or CLPC parameters in operation <NUM> (first UL PC process). If this value is a binary '<NUM>', the UE <NUM> transmits a PUSCH with a transmission power determined according to a second set of values for OLPC or CLPC parameters in operation <NUM> (second UL PC process).

In a second approach for dynamic indication, an indication for the UE <NUM> to use a first set of values or a second set of values for OLPC or CLPC parameters for UL signal transmission in an UL TTI (other than TTI#<NUM>) is by reinterpreting a TPC field of <NUM> bits in a respective DCI format scheduling a PUSCH or A-SRS transmission. A conventional interpretation of a TPC field of <NUM> bits is that each value indicates a transmission power adjustment in deciBels (dB) with '<NUM>', '<NUM>', '<NUM>', and '<NUM>' indicating respectively -<NUM> dB, <NUM> dB, <NUM> dB, and <NUM> dB (see also REF <NUM>). For a PUSCH or an A-SRS transmission in an UL TTI other than TTI#<NUM>, one bit of the TPC field, such as for example the first bit, can be used to indicate a transmission power adjustment and the other bit of the TPC field can be used to indicate a use of a first UL PC process or of a second UL PC process. For example, the values of the transmission power adjustment can be - <NUM> dB or <NUM> dB or can depend on whether a first UL PC process or a second UL PC process is indicated.

<FIG> illustrates an example use of a TPC field in a DCI format scheduling a PUSCH depending on whether it can indicate use of a first UL PC process or a second UL PC process according to this disclosure. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, a UE <NUM> detects a PDCCH conveying a DCI format including a TPC field of <NUM> bits and scheduling a PUSCH transmission in operation <NUM>. The UE <NUM> subsequently examines whether a respective TTI is the UL fixed TTI#<NUM> in operation <NUM>. If it is TTI#<NUM>, the UE <NUM> transmits a PUSCH using a first set of values for OLPC or CLPC parameters corresponding to a first UL PC process and uses a mapping of both bits of the TPC field to determine a value for adjusting a transmission power in operation <NUM>. If the TTI is not TTI#<NUM>, the UE <NUM> determines whether to use a first set of values or a second set of values for OLPC or CLPC parameters, corresponding to a first or second UL PC process respectively, depending on a value of a second bit of the <NUM>-bit TPC field in operation <NUM>. For example, if the second bit value is a binary '<NUM>', the UE <NUM> uses a first UL PC process; otherwise, if the second bit value is a binary '<NUM>', the UE <NUM> uses a second UL PC process. Finally, the UE <NUM> further determines a transmission power adjustment using a mapping of a first bit of the TPC field <NUM>.

In a third approach for dynamic indication, an indication for a UE <NUM> to use a first set of values or a second set of values for OLPC or CLPC parameters for UL signal transmission in an UL TTI (other than TTI#<NUM>) is by re-interpreting states of another field included in a DCI format scheduling a PUSCH to provide the above indication. For example, as a number of UEs with active connection to the eNB <NUM> that are configured operation with an adapted TDD UL-DL configuration is typically not large, a <NUM>-bit CS and OCC index field in a DCI format used for enabling spatial multiplexing of PUSCH transmissions among UEs (also see REF <NUM>) is typically excessive. Then, for a PUSCH transmission in a TTI other than TTI#<NUM>, <NUM> bit from the <NUM> bits of the CS and OCC field can be used to provide an indication for a first UL PC process or for a second UL PC process. Such an approach can be extended to other fields of a DCI format by respectively limiting their scope. As the UE <NUM> operation is similar to that for the second approach, further illustration is omitted for brevity.

For any approach relying on supplemental dynamic indication of a first UL PC process or of a second UL PC process, if a PUSCH transmission conveys a retransmission for a data TB, it occurs in a TTI other than TTI#<NUM>, and it is triggered by an DL HARQ-ACK signal (NACK for a previous transmission of same data TB, see also REF <NUM>), the UE <NUM> needs to implicitly determine whether to use the first UL PC process or the second UL PC process. If the UE <NUM> was scheduled by PDCCH or EPDCCH a PUSCH transmission in a same TTI in a previous frame for a same TDD UL-DL configuration, the UE <NUM> maintains a same (first or second) UL PC process for the PUSCH transmission conveying a retransmission of a data TB. If the UE <NUM> was not scheduled by PDCCH or EPDCCH any PUSCH transmission in a same TTI in a previous frame for a same TDD UL-DL configuration, an implicit rule can apply for the UE <NUM> to determine whether to use the first UL PC process or the second UL PC process. For example, if for an initial transmission of a same data TB, a CS and OCC index field including <NUM> bits in a respective DCI format indicated one of the four smaller values, the UE <NUM> can use a first UL PC for the retransmission of the data TB; otherwise, if the CS and OCC index field indicated one of the four larger values, the UE <NUM> can use a second UL PC for the retransmission of the data TB.

<FIG> illustrates an example process for a UE to determine whether to use a first UL PC process or a second UL PC process for a non-adaptive retransmission of a data TB in a PUSCH according to this disclosure. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, UE <NUM> detects a HARQ-ACK signal conveying a NACK for an initial transmission of a data TB in operation <NUM>. The UE <NUM> transmits a PUSCH conveying a retransmission of the data TB in a TTI (other than TTI#<NUM>) according to a HARQ timeline depending on a TTI index of HARQ-ACK signal detection for a configured TDD UL-DL configuration in operation <NUM>. The UE <NUM> determines whether to use a first UL PC process or a second UL PC process for a PUSCH transmission based on a value of a CS and OCC index field included in a DCI format scheduling the initial PUSCH transmission for the same data TB in operation <NUM>. If the value of the CS and OCC index field is in the lower half of values, the UE <NUM> uses a first UL PC process in operation <NUM>. If the value of the CS and OCC index field is in the upper half of values, the UE <NUM> uses a second UL PC process in operation <NUM>.

A TTI for A-SRS transmission triggered by a DCI format a UE <NUM> detects in DL TTI n is determined as a first UL TTI satisfying n+k,k≥<NUM> and (<NUM>·nf + kSRS - Toffset,<NUM>)mod TSRS,<NUM> = <NUM> where kSRS is a TTI index within a frame nf, Toffset,<NUM> is an A-SRS TTI offset, TSRS,<NUM> is an A-SRS periodicity (see also REF <NUM>). An A-SRS can then be transmitted either in an UL fixed TTI (such as TTI#<NUM>) or in an UL flexible TTI. If an A-SRS transmission is triggered by a PDCCH scheduling a PDSCH and the A-SRS is to be transmitted in an UL flexible TTI, the first two approaches can again be used. Specifically, DCI formats scheduling a PDSCH and supporting A-SRS triggering can either include a PCC field, applicable to A-SRS transmissions in a same manner as the PCC field in DCI formats scheduling a PUSCH for indicating whether a first or a second UL process should be used, or the TPC field can be split into two parts (only when A-SRS is triggered) with a first part indicating a TPC command and a second part acting as a PCC. Alternatively, for an A-SRS transmission triggered by a PDCCH scheduling a PDSCH, a second UL PC process can be used by default as such triggering is primarily beneficial when there is UL-dominant interference. If the A-SRS is to be transmitted in an UL fixed TTI, such as TTI#<NUM>, a conventional UL PC process (first UL PC process) applies.

While two different UL PC processes can apply for PUSCH or A-SRS transmissions, this disclosure considers that PUCCH transmissions can be in fixed TTIs and therefore a single (first) UL PC process suffices. One reason for such a restriction is to protect PUCCH transmissions from DL interference as, unlike data transmissions in PUSCHs, transmission of control information in a PUCCH typically requires higher reception reliability and cannot benefit from HARQ retransmissions. Another reason is that using a second UL PC process and applying a larger transmission power in a UL TTI where legacy UEs transmit control information in PUCCHs (or even data information in PUSCHs) can create unwanted in-band emissions and severely degrade a reception reliability of information transmitted from conventional UEs that use a first UL PC process. A consequence of avoiding in-band emissions and receiving signals using a second UL PC process with much larger power than signals using a first UL PC process in a same TTI is that a second UL PC process may not be used in TTIs where conventional UEs transmit signals even if UE <NUM> experiences primarily DL interference in such TTIs. Therefore, regardless of an UL TTI, a same UL PC process is always used for PUCCH transmissions by both conventional UEs and UEs configured for operation with an adapted TDD UL-DL configuration.

PUCCH transmissions also can occur in an UL flexible TTI, that is an UL TTI other than TTI#<NUM>, that nevertheless cannot be adapted to a DL one, based on another TDD UL-DL configuration that is configured to the UE <NUM> for HARQ-ACK transmissions in response to PDCCH detections. For example, if UL-DL configuration <NUM> is configured to the UE <NUM> for HARQ-ACK transmissions, TTI#<NUM> is always an UL TTI even though it could be an UL flexible TTI if UL-DL configuration <NUM> is configured to the UE <NUM> for HARQ-ACK transmissions (only TTI#<NUM> is always an UL TTI regardless of a TDD UL-DL configuration that is configured to the UE <NUM> for HARQ-ACK transmissions). Then, as this disclosure considers that a first UL PC process is always used for PUCCH transmissions and as TTI#<NUM> can be used for HARQ-ACK signal transmissions from the UE <NUM> in a PUCCH, a first UL PC process is also used for TTI#<NUM>. In general, a first UL PC process is used for all UL signaling (PUSCH, SRS, PUCCH) in every TTI, in addition to TTI#<NUM>, where the UE <NUM> can transmit a PUCCH.

For P-SRS transmissions, as a TTI type (fixed or flexible) is predetermined by configuration, whether a first or a second UL PC process is used is also predetermined by configuration. For a SPS PUSCH transmission, this disclosure further considers that it can always be in a fixed TTI and use a first UL PC process as an adaptation of a TDD UL-DL configuration can be faster than a configuration of an UL TTI where SPS PUSCH is transmitted.

For PUSCH transmissions, an association of an UL TTI with a first UL PC process or a second UL PC process can also rely exclusively on configuration (RRC signaling) without a supplemental dynamic signaling. For example, considering adjacent-channel interference from a cell that does not adapt its TDD UL-DL configuration faster than a conventional one, a use of a first UL PC process or of a second UL PC process in a TTI can be signaled to the UE <NUM> in a semi-static manner by RRC signaling. A same approach can apply for PUSCH retransmission triggered by a HARQ-ACK signal with a NACK value, as there is no associated DCI format to dynamically indicate an UL PC process for the UE to use in a TTI of the PUSCH retransmission, or for an A-SRS configured to occur in an UL flexible TTI and triggered by an adaptation of a TDD UL-DL configuration.

Considering a frame of <NUM> TTIs and that TTI#<NUM> is an UL fixed TTI while TTI#<NUM>, TTI#<NUM>, TTI#<NUM> are either fixed DL TTIs or fixed special TTIs (having a same configuration of DwPTS length and UpPTS length) in all TDD UL-DL configurations, the RRC signaling can be a bit-map that includes <NUM> bits (for flexible TTI#<NUM>, TTI#<NUM>, TTI#<NUM>, TTI#<NUM>, TTI#<NUM>, and TTI#<NUM>) wherein, for a respective TTI, a bit value of '<NUM>' can indicate use of a first UL PC process while a bit value of '<NUM>' can indicate use of a second UL PC process. A reason for a possible association of a second UL PC process with TTI#<NUM> is because if it is a special TTI it can support UL transmissions in the UpPTS, such as for example SRS transmissions, and the UE <NUM> can experience either UL interference or DL interference (if it is a DL TTI in a TDD UL-DL configuration used in an adjacent cell). A bit-map can also be defined with a size equal to a number flexible TTIs in a conventional TDD UL-DL configuration and in such case it can include less than <NUM> bits. An association by RRC signaling of UL TTIs in a frame in a first set of TTIs associated with a first UL PC process and in a second set of TTIs associated with a second UL PC process is sufficient in case an interfering cell uses a conventional adaptation of its TDD UL-DL configuration.

The invention additionally considers that a use of a second UL PC process is configured to the UE <NUM> by RRC signaling. For example, if a cell belongs in a cluster of cells using a same adaptation of a TDD UL-DL configuration and interference to a cell, in the cluster of cells, is predominantly generated by cells in the same cluster, a second UL PC process is not necessary as UL transmissions in a cell experience interference from other cells in the same cluster.

In certain embodiments, TPC commands for adjusting a PUSCH transmission power or a SRS transmission power are also provided to a group of UEs through a transmission of DCI format <NUM>/3A, with CRC scrambled with a TPC-RNTI. When separate UL PC processes are used between transmissions in a first set of UL TTIs and transmissions in a second set of UL TTIs, there is a need to identify TPC commands for each UL PC process.

In a first approach, a separate TPC-RNTI is associated with TPC commands applicable to the second set of UL TTIs and is configured to the UE <NUM> by higher layer signaling such as RRC signaling. Therefore, when detecting a respective PDCCH conveying a DCI format <NUM>/3A, the UE <NUM> performs a CRC check after descrambling a CRC either with a first TPC-RNTI corresponding to a DCI format <NUM>/3A providing TPC commands for a first UL PC process or with a second TPC-RNTI corresponding to a DCI format <NUM>/3A providing TPC commands for a second UL PC process.

<FIG> illustrates an example process for the UE <NUM> to obtain TPC commands for a first UL PC process and TPC commands for a second UL PC process from different respective DCI formats <NUM>/3A according to this disclosure, not forming part of the claimed invention. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the UE <NUM> receives a PDCCH potentially conveying a DCI format <NUM>/3A and descrambles its CRC using a first TPC-RNTI and using a second TPC-RNTI and performs a first respective CRC check and a second respective CRC check in operation <NUM>. The UE <NUM> subsequently examines outcomes of respective first and second CRC checks in operation <NUM>. If none of the CRC checks is positive, the UE <NUM> ignores the PDCCH decoding result in operation <NUM>. If the first CRC check is positive in operation <NUM>, the UE <NUM> uses a TPC command in the DCI format for a first UL CLPC process for adjusting a PUSCH or SRS transmission power in operation <NUM>; otherwise, the UE <NUM> uses a TPC command in the DCI format for a second UL CLPC process for adjusting a PUSCH or SRS transmission power in operation <NUM>.

In a second approach, a TPC command applicable to a first UL PC process and a TPC command applicable to a second UL PC process are provided in a same DCI format <NUM>/3A. The UE <NUM> is configured (for example, by RRC signaling) a first location for a TPC command applicable to a first UL PC process and it implicitly determines a TPC command applicable to a second UL PC process to be located immediately after the TPC command applicable to the first UL PC process.

<FIG> illustrates an example UE determination of a TPC command for a first UL PC process and of a TPC command for a second UL PC process in a same DCI format <NUM>/3A according to this disclosure, not forming part of the claimed invention. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, UE <NUM> receives a PDCCH potentially conveying a DCI format <NUM>/3A, descrambles its CRC using a TPC-RNTI and performs a CRC check in operation <NUM>. The UE <NUM> subsequently examines an outcome of the CRC checks in operation <NUM>. If the CRC check is negative, the UE <NUM> ignores the PDCCH decoding result in operation <NUM>. If the CRC check is positive, the UE <NUM> uses a first TPC command in the DCI format for a first CLPC process for adjusting a PUSCH or a SRS transmission power in operation <NUM>. The UE also uses a second TPC command in the DCI format for a second CLPC process for adjusting a PUSCH or a SRS transmission power in operation <NUM> wherein a location of the second TPC command is either separately configured from a location of the first TPC command or it follows immediately after a location of the first TPC command.

In addition to a DCI format <NUM>/3A providing a TPC command for adjusting a PUSCH transmission power or a SRS transmission power in flexible TTIs, it can also be beneficial to indicate the flexible TTIs for which the transmission power adjustment is applicable (as not all flexible TTIs apply a same UL PC process). A same approach as for non-adaptive retransmission of a data TB in a PUSCH can apply.

Finally, considering that a TPC command provided by DCI format <NUM>/3A to the UE <NUM> primarily intends to adjust a transmission power of periodic signaling, such as SPS PUSCH, or P-SRS, or UCI transmitted in PUCCH (other than HARQ-ACK that is in response to PDCCH detections by the UE <NUM> that convey DCI formats that include at least one TPC command), as a transmission power for non-periodic signaling triggered by detection of DCI formats can be adjusted from a TPC command included in a respective DCI format, supporting TPC commands by DCI format <NUM>/3A exclusively for the second UL PC process can be avoided and the UE <NUM> can interpret such TPC commands as always applying either only to the first UL PC process or for both the first UL PC process and the second UL PC process.

This embodiment considers that after an adaptation of a TDD UL-DL configuration, an interference experienced by PUSCH or SRS transmissions from the UE <NUM> in a flexible TTI can change depending on TDD UL-DL configurations used in adjacent cells. Therefore, it may not be appropriate to continue using a same CLPC process from a previous TDD UL-DL configuration for PUSCH or SRS transmissions in flexible TTIs if the TPC commands are accumulative.

This disclosure considers that after an adaptation of a TDD UL-DL configuration, a second CLPC process, fc,<NUM>, for PUSCH or SRS transmissions from the UE <NUM> in a second set of TTIs is re-initialized while a first CLPC process, fc,<NUM>, for PUSCH or SRS transmissions from the UE <NUM> in a first set of TTIs continues from its latest value during a previous TDD UL-DL configuration. In order to maintain tracking of channel variations for adapting a PUSCH or SRS transmission power in a second set of TTIs associated with a second UL PC process after an adaptation of a TDD UL-DL configuration, the UE <NUM> re-initializes fc,<NUM> with a last value of fc,<NUM> during the previous TDD UL-DL configuration. Alternatively, prior to receiving a TPC command applicable to a current TDD UL-DL configuration, the UE <NUM> can re-initialize fc,<NUM> with the current value of fc,<NUM>. Also, when <NUM> is configured to operate with a second UL PC process, an initial value for fc,<NUM> can be same as an existing value of fc,<NUM> at the time of the configuration. This can also be extended to any case where the UE <NUM> transitions its operation from a conventional TDD UL-DL configuration to an adapted TDD UL-DL configuration. For example, the UE <NUM> can initialize fc,<NUM> with an existing value of fc,<NUM>, when the UE <NUM> fails to detect a first DCI format indicating a first adapted TDD UL-DL configuration for an adaptation period (UE <NUM> then operates with the conventional TDD UL-DL configuration using the first UL PC process) and the UE <NUM> subsequently detects a second DCI format indicating a second adapted TDD UL-DL configuration for the adaptation period. Alternatively, a configuration for use of accumulative or absolute TPC can be independent for a first CLPC process and a second CLPC process. Alternatively, if the UE <NUM> did not operate with an adapted TDD UL-DL configuration.

<FIG> illustrates an example operation of a first CLPC process and of a second CLPC process after an adaptation of a TDD UL-DL configuration according to this disclosure. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the UE <NUM> determines an adaptation of a TDD UL-DL configuration in operation <NUM>. The UE <NUM> sets fc,<NUM> equal to a last value of fc,<NUM> during a previous TDD UL-DL configuration (or equal to a current value of fc,<NUM>) in operation <NUM>. The UE <NUM> uses a last value of fc,<NUM> in a previous TDD UL-DL configuration to update fc,<NUM> in a current TDD UL-DL configuration in operation <NUM>.

In certain embodiments, due to different interference characteristics a PUSCH transmission from the UE <NUM> can experience among fixed TTIs, such as TTI#<NUM>, and at least some flexible TTIs, and despite a possible use of different respective UL PC processes to account for the different interference, the UE <NUM> can operate with different respective BLERs for a transmission of data TBs. For example, interference to a PUSCH transmission from the UE <NUM> in some flexible TTIs can be from DL transmissions and can be much more severe than interference to a PUSCH transmission from the UE <NUM> in an UL fixed TTI which is always from UL transmissions.

Although a target BLER for a data TB can be adjusted to account for variations in general operating conditions, including interference conditions, a UCI target BLER is typically fixed regardless of the operating conditions. A UCI transmission in a PUCCH can be only in fixed TTIs, such as TTI#<NUM> for the TDD UL-DL configurations in Table <NUM>, and in that case it experiences practically stable operating conditions. However, a UCI transmission in a PUSCH, such as an aperiodic CSI transmission triggered by a PDCCH conveying a DCI format scheduling the PUSCH, can be either in a fixed TTI or in a flexible TTI. If a CSI transmission is multiplexed in a PUSCH in a flexible TTI then, depending on respective interference conditions, a respective number of REs allocated to CSI may need to be adjusted to account for a different operating BLER for data TBs in the flexible TTI relative to a fixed TTI. Since for practical reasons a power of REs in a same PUSCH symbol is same, separate power control for CSI REs and data information REs in a PUSCH is not possible. However, adjusting a number of REs used for CSI multiplexing in a PUSCH is functionally equivalent to performing UL PC for CSI separate from UL PC for data information. Additionally, even though a first UL PC process can be used for PUSCH transmissions in fixed TTIs and a second UL PC process can be used for PUSCH transmissions in at least some flexible TTIs, the second UL PC process may not be sufficient for improving a reception reliability for data TBs or for CSI as a respective UE may be power limited (already operating near maximum transmission power) or a network may choose to not significantly increase a respective transmission power to avoid creating significant interference.

To account for a different BLER of data TBs in a PUSCH between TTIs experiencing significantly different interference conditions while maintaining a same UCI BLER regardless of the TTI type, a different <MAT> can be used for CSI transmission in a flexible TTI than in a fixed TTI. Therefore, the UE <NUM> can be configured by the eNB <NUM> two <MAT> values with a first <MAT> value being used for CSI multiplexing in a PUSCH transmitted in a first set of TTIs, such as a fixed TTI or in a flexible TTI where the UE <NUM> experiences statistically similar interference as for a fixed TTI, and a second <MAT> value being used for CSI multiplexing in a PUSCH transmitted in a second set, such as for flexible TTIs where a PUSCH transmission experiences materially different interference than it does in a fixed TTI. Moreover, as SPS PUSCH transmissions are considered to be in a fixed TTI, the first <MAT> value is used in case a respective CSI is multiplexed in a SPS PUSCH transmission.

<FIG> illustrates an example use of a first <MAT> for determining a number of CSI resources in a first TTI and a use of a second <MAT> for determining a number of CSI resources in a second TTI according to this disclosure, not forming part fo the claimed invention. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the UE <NUM> detects a PDCCH conveying a DCI format scheduling a PUSCH in a TTI in operation <NUM>. The UE <NUM> multiplexes a CSI in the PUSCH by determining a respective number of REs either using a first <MAT> value in operation <NUM> if the PUSCH is transmitted in a first TTI from a first set of TTIs in a frame or using a second <MAT> value in operation <NUM> if the PUSCH is transmitted in a second TTI from a second set of TTIs in a frame. Therefore, <MAT> is used for CSI transmission in a PUSCH for first set of TTIs in a frame and <MAT> is used for CSI transmission in a PUSCH for second set of TTIs in a frame.

A use of a first <MAT> or of a second <MAT> in determining a number of REs for a respective CSI multiplexing in a PUSCH transmission in a TTI can be indicated to the UE <NUM> in a same manner as a use of a first UL PC process or of a second UL PC process for a PUSCH transmission, as it was previously described (configuration by RRC signaling or dynamic indication by a DCI format). Furthermore, a use of a first <MAT> can be directly linked with a use of a first UL PC process while a use of a second <MAT> can be directly linked with a use of a second UL PC process (a first set of TTIs in a frame is configured to use a first UL PC process and a first <MAT> and a second set of TTIs in a frame is configured to use a first UL PC process and a second <MAT>).

In certain embodiments, similar to link adaptation of UCI transmissions in a PUSCH that can experience different interference characteristics between a fixed TTI and at least one flexible TTI, such link adaptation can also be beneficial for transmissions of data TBs. As previously discussed, a use of separate UL PC processes for UL signaling from a UE <NUM> in TTIs with UL dominant interference and in TTIs with DL dominant interference can improve a reception reliability in TTIs where interference is primarily from DL transmissions to other UEs but it can often be difficult (for example, due to UE transmit power limitations or due to limitations in additional UL interference) to provide a comparable reception reliability as in TTIs where interference is primarily from UL transmissions from other UEs.

Regardless of whether a retransmission of a data TB in a PUSCH is adaptive (triggered by a detection of a respective PDCCH) or non-adaptive (triggered by a detection of a NACK value in a respective HARQ-ACK signal), a same Modulation and Coding Scheme (MCS) index IMCS is used as for a respective initial transmission of the data TB and only a Redundancy Version (RV) for a HARQ process using Incremental Redundancy (IR) is updated. Although keeping a same MCS is appropriate when a retransmission of a data TB experiences statistically a same interference as an initial transmission of the data TB, this can be detrimental when the interference is significantly different between the two transmissions.

In a first approach, when a PUSCH conveying an initial transmission of a data TB is transmitted in a fixed TTI or in a flexible TTI where a respective UE experiences dominant interference from UL transmissions from other UEs, and a PUSCH conveying a retransmission of a same data TB is transmitted in a flexible TTI where a respective UE experiences dominant interference from DL transmissions to other UEs, it can be beneficial for the MCS used in the retransmission of the data TB to be lower than the MCS used for the initial transmission of the same data TB. This can provide a comparable reliability for values of demodulated data bits (prior to decoding) as for the initial transmission of the data TB and enable proper combining of respective values prior to data TB decoding. Conversely, when a PUSCH conveying an initial transmission of a data TB is transmitted in a flexible TTI where a respective UE experiences dominant interference from DL transmissions to other UEs and a PUSCH conveying a retransmission of a same data TB is transmitted in a fixed TTI or in a flexible TTI where a respective UE experiences dominant interference from UL transmissions from other UEs, it can be beneficial for the MCS used for the retransmission of the data TB to be higher than the MCS used for the initial transmission of the same data TB.

*150The present disclosure considers that the eNB <NUM> configures the UE <NUM> with a MCS index shift IMCS_shift that the UE <NUM> can apply in determining an MCS index for a retransmission of a data TB. If an interference in a TTI conveying a retransmission of a data TB in a PUSCH is statistically different than an interference in a TTI conveying an initial transmission of the same data TB in a PUSCH, and denoting by IMCS_initial an MCS index for the initial transmission of the data TB, the UE <NUM> determines an MCS index IMCS_retransmission for the retransmission of the data TB as IMCS_retransmission = max(IMCS_initial - IMCS_shift,IMCS_min) if a TTI of the initial transmission is of a same type as a TTI of a first UL PC process and a TTI of the retransmission if of a same type as a TTI of a second UL PC process. Otherwise, if a TTI of the initial transmission is of a same type as a TTI of a second UL PC process and a TTI of the retransmission if of a same type as a TTI of a first UL PC process, IMCS_retrammission = min(IMCS_initial + IMCS_shift,IMCS_max). IMCS_min and IMCS_max are respectively the minimum and maximum MCS indexes supported for the UE <NUM> operation. The association of a TTI type to an UL PC process is with respect to previously described determination methods for using a first UL PC process (TTI is in a first set) or a second UL PC process (TTI is in a second set) and is independent of whether more than one UL PC processes are actually used. Conversely, if an interference in a TTI conveying a retransmission of a data TB in a PUSCH is statistically same as an interference in a TTI conveying an initial transmission of the same data TB in a PUSCH, an MCS shift is not used. Then, IMCS_retransmission = IMCS_initial.

<FIG> illustrates an example use of a MCS index shift IMCS_shift for UE <NUM> to determine a MCS index for a retransmission of a data TB according to this disclosure, not forming part of the claimed invention. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the eNB <NUM> configures, using higher layer signaling, a MCS index shift IMCS_shift to the UE <NUM><NUM>. For a retransmission of a data TB in a PUSCH in a second TTI in operation <NUM>, the UE <NUM> determines whether the second TTI is of a same type as a first TTI for an initial transmission of the same data TB in a respective PUSCH in operation <NUM>. A TTI can be of a first type or of a second type and a respective determination can be as previously described for the UE <NUM> to determine whether to apply a first UL PC process or a second UL PC process for a respective PUSCH transmission. If the first TTI and the second TTI are of a same type, the UE <NUM> determines a MCS index for a retransmission of a data TB, IMCS_retrammission, to be same as a MCS index for an initial transmission of the same data TB, IMCS_initial <NUM>. If the first TTI and the second TTI are not of a same type, the UE <NUM> determines a MCS index for a retransmission of a data TB as IMCS_retransmission = max(IMCS_initial - IMCS_shift,IMCS_min) if the first TTI is of a first type and the second TTI is of a second type in operation <NUM> or as IMCS_retransmission = min(IMCS_initial + IMCS_shift,IMCS_max) if the first TTI is of a second type and the second TTI is of a first type in operation <NUM>.

In a second approach, a same MCS can be used for an initial transmission and for a retransmission of a same data TB but the eNB <NUM> can scale differently, before combining for data TB decoding, values of demodulated data bits it receives in a TTI where the UE <NUM> experiences UL-dominant interference and applies a first UL PC process and values of demodulated data bits it receives in a TTI where the UE <NUM> experiences DL-dominant interference and applies a second UL PC process. This allows obtaining a functionally similar operation as applying an MCS shift, as it was previously discussed but, instead of applying such an adjustment at the UE <NUM> transmission for a retransmission of a data TB, a similar adjustment is applied at the eNB <NUM> reception for a retransmission of a data TB.

<FIG> illustrates an example scaling of demodulated values for data information bits from a retransmission of a data TB before combining with demodulated values for data information bits from an initial transmission of a same data TB prior to decoding according to this disclosure, not forming part of the claimed invention. While the flow chart depicts a series of sequential steps, unless explicitly stated, no inference should be drawn from that sequence regarding specific order of performance, performance of steps or portions thereof serially rather than concurrently or in an overlapping manner, or performance of the steps depicted exclusively without the occurrence of intervening or intermediate steps. The process depicted in the example depicted is implemented by a transmitter chain in, for example, a mobile station.

As shown in <FIG>, the eNB <NUM> receives a retransmission of a data TB in a second TTI in operation <NUM> and considers whether the second TTI is of a same type as a first TTI where the eNB <NUM> receives an initial transmission of the same data TB in operation <NUM>. If it is, demodulated data bits corresponding to encoded data information bits received in the second TTI are scaled with a first number before being combined with demodulated data bits corresponding to encoded data information bits received in the first TTI prior to decoding in operation <NUM>. For example, the first number can be equal to one and demodulated data bits are combined with their actual values that capture a respective SINR. If it is not, and the first TTI is of a first type and the second TTI is of a second type, demodulated data bits corresponding to encoded data information bits received in the second TTI are scaled with a second number before being combined with demodulated data bits corresponding to encoded data information bits received in the first TTI prior to decoding in operation <NUM>. For example, the second number can be smaller than one. If it is not, and the first TTI is of a second type and the second TTI is of a first type, demodulated data bits corresponding to encoded data information bits received in the second TTI are scaled with a third number before being combined with demodulated data bits corresponding to encoded data information bits received in the first TTI prior to decoding in operation <NUM>. For example, the third number can be larger than one. Similar to a use of an MCS shift, such scaling is particularly applicable if the second UL PC process cannot fully compensate for the DL-dominant interference in the second set of UL TTIs due to limitations in UL transmission power from a UE <NUM> either because additional power is unavailable or because it is beneficial to avoid increasing interference to other cells.

Claim 1:
A method, performed by a user equipment, UE, (<NUM>) of controlling uplink, UL, power, the method comprising:
receiving configuration information about two power control processes including a first UL power control process and a second UL power control process for closed loop power control, CLPC;
receiving (<NUM>) downlink control information, DCI, wherein the DCI includes transmission power control command and indication having one bit binary element; and
determining (<NUM>) transmission power for transmitting a physical uplink shared channel, PUSCH, based on the transmission power control command and the indication,
wherein the indication indicates one of the two power control processes.