Patent Description:
<NPL> et al describes multiple starting and ending positions in a sub frame for UL.

The described techniques relate to improved methods, systems, devices, or apparatuses that support partial subframe transmission techniques in shared radio frequency spectrum. As indicated above, in some cases, unlicensed radio frequency spectrum bands may be used for Long Term Evolution (LTE), LTE-Advanced (LTE-A), or new radio (NR) communications. Unlicensed radio frequency spectrum may be used in combination with, or independent from, a dedicated or licensed radio frequency spectrum band. The dedicated radio frequency spectrum band may include a radio frequency spectrum band licensed to particular users for particular uses. The unlicensed or shared radio frequency spectrum band may include a radio frequency spectrum band available for Wi-Fi use, a radio frequency spectrum band available for use by different radio access technologies, or a radio frequency spectrum band available for use by multiple mobile network operators (MNOs) in an equally shared or prioritized manner and may be accessed through contention-based access procedures. The terms unlicensed radio frequency spectrum and shared radio frequency spectrum are used interchangeably herein.

In some cases, a base station may schedule a user equipment (UE) for downlink and uplink communications through an assignment or grant of resources. However, due to contention-based access, the timing of when a base station or UE has access to shared radio frequency spectrum may not be known until a contention-based access procedure (e.g., a listen-before-talk (LBT) procedure) is completed. Furthermore, in some cases, subframe timing between multiple transmitters that use the shared radio frequency spectrum may be synchronized, and thus time gaps may be present between completion of an LBT procedure and a subsequent start of a subframe. Techniques discussed herein provide for efficient scheduling and transmissions following a successful contention-based access procedure, which may enhance the efficiency of a network that uses shared radio frequency spectrum.

In some cases, a base station may identify of a starting location for a transmission and initiate the transmission in a relatively short time period between completion of a successful LBT procedure and transmission of data between the base station and a UE. In the event that an LBT procedure is successfully completed after the start of a subframe, an indication of a transmission may be transmitted at one of a number of predetermined points within the subframe time duration. In some cases, two or more different partial subframe durations may be configured, and one or more different partial subframes may be used for transmissions until the start of a subsequent subframe.

In some cases, a base station may provide an uplink grant to a UE, and the UE may start uplink transmissions based on an established timing between receiving the uplink grant and the start of the uplink transmissions. The uplink grant, in some cases, may be transmitted using a partial subframe, which may allow a UE to start uplink transmissions sooner than uplink transmissions would be started if the uplink grant were transmitted using a full subframe. In some cases, an uplink grant may be provided to a UE, and a separate trigger may be transmitted to initiate the uplink transmission, and the trigger may be transmitted in a partial subframe and may include an indication of a starting or ending position, or both, of the uplink transmission.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to partial subframe transmission techniques in shared radio frequency spectrum.

<FIG> illustrates an example of a wireless communications system <NUM> in accordance with various aspects of the present disclosure. The wireless communications system <NUM> includes base stations <NUM>, UEs <NUM>, and a core network <NUM>. In some examples, the wireless communications system <NUM> may be a Long Term Evolution (LTE), LTE-Advanced (LTE-A) network, or a New Radio (NR) network. In some cases, wireless communications system <NUM> may support enhanced broadband communications, ultra-reliable (i.e., mission critical) communications, low latency communications, and communications with low-cost and low-complexity devices. Wireless communications system <NUM> may be an example of a system that supports partial subframe transmissions in shared radio frequency spectrum.

Each base station <NUM> may provide communication coverage for a respective geographic coverage area <NUM>. Control information and data may be multiplexed on an uplink channel or downlink according to various techniques. Control information and data may be multiplexed on a downlink channel, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, the control information transmitted during a transmission time interval (TTI) of a downlink channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region and one or more UE-specific control regions).

A UE <NUM> may also be referred to as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may also be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a personal electronic device, a handheld device, a personal computer, a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, a machine type communication (MTC) device, an appliance, an automobile, or the like.

In some cases, an MTC device may operate using half-duplex (one-way) communications at a reduced peak rate. MTC devices may also be configured to enter a power saving "deep sleep" mode when not engaging in active communications. In some cases, MTC or IoT devices may be designed to support mission critical functions and wireless communications system may be configured to provide ultra-reliable communications for these functions.

Base stations <NUM> may also be referred to as evolved NodeBs (eNBs) <NUM>, or, in NR networks, next generation eNBs (gNBs).

At least some of the network devices, such as base station <NUM> may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC). Each access network entity may communicate with a number of UEs <NUM> through a number of other access network transmission entities, each of which may be an example of a smart radio head, or a transmission/reception point (TRP).

Wireless communications system <NUM> may operate in an ultra-high frequency (UHF) frequency region using frequency bands from <NUM> to <NUM> (<NUM>), although some networks (e.g., a wireless local area network (WLAN)) may use frequencies as high as <NUM>. This region may also be known as the decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may propagate mainly by line of sight, and may be blocked by buildings and environmental features. However, the waves may penetrate walls sufficiently to provide service to UEs <NUM> located indoors. Transmission of UHF waves is characterized by smaller antennas and shorter range (e.g., less than <NUM>) compared to transmission using the smaller frequencies (and longer waves) of the high frequency (HF) or very high frequency (VHF) portion of the spectrum. In some cases, wireless communications system <NUM> may also utilize extremely high frequency (EHF) portions of the spectrum (e.g., from <NUM> to <NUM>). This region may also be known as the millimeter band, since the wavelengths range from approximately one millimeter to one centimeter in length. Thus, EHF antennas may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE <NUM> (e.g., for directional beamforming). However, EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than UHF transmissions.

Thus, wireless communications system <NUM> may support millimeter wave (mmW) communications between UEs <NUM> and base stations <NUM>. Devices operating in mmW or EHF bands may have multiple antennas to allow beamforming. That is, a base station <NUM> may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE <NUM>. Beamforming (which may also be referred to as spatial filtering or directional transmission) is a signal processing technique that may be used at a transmitter (e.g., a base station <NUM>) to shape and/or steer an overall antenna beam in the direction of a target receiver (e.g., a UE <NUM>). This may be achieved by combining elements in an antenna array in such a way that transmitted signals at particular angles experience constructive interference while others experience destructive interference.

Multiple-input multiple-output (MIMO) wireless systems use a transmission scheme between a transmitter (e.g., a base station <NUM>) and a receiver (e.g., a UE <NUM>), where both transmitter and receiver are equipped with multiple antennas. Some portions of wireless communications system <NUM> may use beamforming. For example, base station <NUM> may have an antenna array with a number of rows and columns of antenna ports that the base station <NUM> may use for beamforming in its communication with UE <NUM>. Signals may be transmitted multiple times in different directions (e.g., each transmission may be beamformed differently). A mmW receiver (e.g., a UE <NUM>) may try multiple beams (e.g., antenna subarrays) while receiving the synchronization signals.

In some cases, the antennas of a base station <NUM> or UE <NUM> may be located within one or more antenna arrays, which may support beamforming or MIMO operation. One or more base station antennas or antenna arrays may be collocated at an antenna assembly, such as an antenna tower. A base station <NUM> may multiple use antennas or antenna arrays to conduct beamforming operations for directional communications with a UE <NUM>.

The MAC layer may also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE <NUM> and a network device <NUM>-c, network device <NUM>-b, or core network <NUM> supporting radio bearers for user plane data.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit (which may be a sampling period of Ts = <NUM>/<NUM>,<NUM>,<NUM> seconds). Time resources may be organized according to radio frames of length of <NUM> (Tf = 307200Ts), which may be identified by a system frame number (SFN) ranging from <NUM> to <NUM>. Each frame may include ten <NUM> subframes numbered from <NUM> to <NUM>. A subframe may be further divided into two. <NUM> slots, each of which contains <NUM> or <NUM> modulation symbol periods (depending on the length of the cyclic prefix prepended to each symbol). Excluding the cyclic prefix, each symbol contains <NUM> sample periods. In some cases the subframe may be the smallest scheduling unit, also known as a TTI. In other cases, a TTI may be shorter than a subframe or may be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs).

A resource element may consist of one symbol period and one subcarrier (e.g., a <NUM> frequency range). A resource block may contain <NUM> consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each OFDM symbol, <NUM> consecutive OFDM symbols in the time domain (<NUM> slot), or <NUM> resource elements. The number of bits carried by each resource element may depend on the modulation scheme (the configuration of symbols that may be selected during each symbol period). Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate may be.

Wireless communications system <NUM> may support operation on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), a layer, a channel, etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably herein. A UE <NUM> may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation.

In some cases, wireless system <NUM> may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless system <NUM> may employ LTE License Assisted Access (LTE-LAA) or LTE Unlicensed (LTE U) radio access technology or NR technology in an unlicensed band such as the <NUM> Industrial, Scientific, and Medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations <NUM> and UEs <NUM> may employ listen-before-talk (LBT) procedures (such as a clear channel assessment (CCA)) to ensure the channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a CA configuration in conjunction with CCs operating in a licensed band. Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, or both. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD) or a combination of both.

A CCA may include an energy detection or energy sensing procedure to determine whether there are any other active transmissions. For example, each base station <NUM> or UE <NUM> may randomly choose a backoff counter (with may be a certain duration or a number of symbols) and listen to a channel including resources that are being contended for until the counter decrements to zero. If the counter reaches zero for a certain base station <NUM> or UE <NUM> and no other transmissions are detected, the base station <NUM> or UE <NUM> may start transmitting. If the counter does not reach zero before another signal is detected, the device has lost contention for resource and refrains from transmitting.

As indicated above, in some cases base stations <NUM> and UEs <NUM> may transmit according to synchronized subframes across devices. However, due to contention-based access, the timing of when a base station <NUM> or UE <NUM> has access to shared radio frequency spectrum may not be known until a LBT procedure is completed. In some cases, a base station <NUM> may identify a starting location for a transmission and initiate the transmission in a relatively short time period between completion of a successful LBT procedure and transmission of data between the base station <NUM> and a UE <NUM>. In the event that an LBT procedure is successfully completed after the start of a subframe, an indication of a transmission may be transmitted at one of a number of predetermined points (e.g., using a common reference signal (CRS) transmission or a demodulation reference signal (DMRS) transmission) within the subframe time duration. In some cases, two or more different partial subframe durations may be configured, and one or more different partial subframes may be used for transmissions until the start of a subsequent subframe.

In some cases, a base station <NUM> may provide an uplink grant to a UE <NUM>, and the UE <NUM> may start uplink transmissions based on an established timing between receiving the uplink grant and the start of the uplink transmissions. The uplink grant may, in some cases, be transmitted using a partial subframe, which may allow a UE <NUM> to start uplink transmissions sooner than uplink transmissions would be started if the uplink grant were transmitted using a full subframe. In some cases, an uplink grant may be provided to a UE <NUM>, and a separate trigger may be transmitted to initiate the uplink transmission, and the trigger may be transmitted in a partial subframe and may include an indication of a starting or ending position, or both, of the uplink transmission.

<FIG> shows a block diagram of a design of a base station <NUM> and a UE <NUM>, which may be one of the base station and one of the UEs in <FIG>. At the base station <NUM>, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor <NUM> may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a through 232t. Downlink signals from modulators 232a through 232t may be transmitted via the antennas 234a through 234t, respectively.

At the UE <NUM>, the antennas 252a through 252r may receive the downlink signals from the base station <NUM> and may provide received signals to the demodulators (DEMODs) 254a through 254r, respectively. A MIMO detector <NUM> may obtain received symbols from all the demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols.

On the uplink, at the UE <NUM>, a transmit processor <NUM> may receive and process data (e.g., for the PUSCH) from a data source <NUM> and control information (e.g., for the PUCCH) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by the modulators 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the base station <NUM>. At the base station <NUM>, the uplink signals from the UE <NUM> may be received by the antennas <NUM>, processed by the demodulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE <NUM>. The processor <NUM> may provide the decoded data to a data sink <NUM> and the decoded control information to the controller/processor <NUM>.

The controller/processor <NUM> and/or other processors and modules at the base station <NUM> may perform or direct the execution of various processes for the techniques described herein. The controllers/processor <NUM> and/or other processors and modules at the UE <NUM> may also perform or direct the execution of the functional blocks illustrated in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, and/or other processes for the techniques described herein. The memories <NUM> and <NUM> may store data and program codes for the base station <NUM> and the UE <NUM>, respectively.

<FIG> illustrates an example of a wireless communications system <NUM> that supports partial subframe transmission techniques in shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless communications system <NUM> includes a base station <NUM>-a and a UE <NUM>-a, which may be examples of aspects of a base station <NUM> or UE <NUM> as described above with reference to <FIG> and <FIG>. In the example of <FIG>, the wireless communications system <NUM> may operate according to a radio access technology (RAT) such as a LTE, <NUM>, or NR RAT, although techniques described herein may be applied to any RAT and to systems that may concurrently use two or more different RATs.

The base station <NUM>-a may communicate with UE <NUM>-a, and one or more other UEs within a coverage area <NUM>-a of the base station <NUM>-a, over a downlink carrier <NUM> and an uplink carrier <NUM>. In some examples, the base station <NUM>-a may allocate resources for communication with UE <NUM>-a over downlink carrier <NUM> and uplink carrier <NUM>. For example, base station <NUM>-a may allocate downlink subframes <NUM> in downlink carrier <NUM> for downlink transmissions from UE <NUM>-a, and one or more downlink subframes <NUM> may correspond to a TTI of <NUM>. In this example, downlink subframes <NUM> may include a first downlink subframe <NUM>-a, a second downlink subframe <NUM>-b, and a third downlink subframe <NUM>-c. Each of the downlink subframes <NUM> includes two slots, in which each slot has seven OFDM symbols for a normal cyclic prefix. In this example, a first slot (slot <NUM>) <NUM> and a second slot (slot <NUM>) <NUM> are included in the first subframe <NUM>-a. Similar transmission resources may be allocated in uplink carrier <NUM> for uplink subframes <NUM>.

As indicated above, in some cases an LBT procedure may result in the base station <NUM>-a gaining channel access between starting points of consecutive downlink subframes <NUM>. In the example of <FIG>, within the first slot <NUM>, the base station <NUM>-a may complete an LBT procedure and gain channel access and begin transmissions at some point after the start of the downlink subframe. Thus, within the first slot <NUM>, there may be a period <NUM> with no transmissions, followed by an initial transmission <NUM> that begins between consecutive starting locations of consecutive downlink subframes <NUM>. While this example shows the initial transmission <NUM> starting within the first slot <NUM>, in other examples the initial transmission <NUM> may start at a starting point of the second slot <NUM>, or after the start of the second slot <NUM>.

In some cases, base station <NUM>-a may configure two or more partial subframe durations to accommodate different starting times of the initial transmission <NUM>. For example, the base station <NUM>-a may configure a first partial subframe duration that corresponds to three OFDM symbols, and a second partial subframe duration that corresponds to a slot duration. Thus, in the event that initial transmission <NUM> starts within the first slot <NUM>, a first partial subframe may be transmitted with the first partial subframe duration, followed by a transmission of a second partial subframe with the second partial subframe duration, which may then be followed by one or more full subframes having a full subframe duration. In some cases, predefined potential starting points for a partial subframe transmission may be configured by the base station <NUM>-b. In some cases, the potential starting points correspond to OFDM symbols within a subframe that may be used to transmit a cell-specific reference signal (CRS). Thus, UE <NUM>-a may monitor for CRS in the configured symbols and, upon detection of CRS, may determine that a partial subframe is being transmitted. Additionally or alternatively, the potential starting points correspond to OFDM symbols within a subframe that contain a demodulation reference signal (DMRS). Thus, UE <NUM>-a may monitor for DMRS and/or CRS in configured symbols and, upon detection of CRS/DMRS, may determine that a partial subframe is being transmitted.

Various design options and configurations may be applied for downlink and uplink partial subframes in shared spectrum environments, such as LAA and the like. In current standards discussions, additional downlink starting points for initial partial subframes has been discussed, as well as at least one additional uplink starting point and at least one additional uplink ending point for initial and ending partial uplink subframes.

In one option for downlink initial partial subframes, specific symbols may be configured for starting points for downlink transmissions (e.g., symbols <NUM>, <NUM>, <NUM>, and <NUM>). Such a design may be similar to existing LAA initial partial subframes in which no transport block size scaling occurs, but rate matching is performed to fit the number of symbols in the partial subframe.

Another option for downlink initial partial subframes provides for staring points at other symbols that are consistent with the short TTI start symbols. In such options, the PDCCH points to the start of transmission which would last until the end of the partial subframe.

In still another option for downlink initial partial subframes, the PDCCH may indicate the start of the PDSCH, which may occur in any position or positions within the subframe, while PDCCH would be transmitted at the first symbol of the first slot of the subframe (e.g., symbol <NUM>) and the first symbol of the second slot of the subframe (e.g., symbol <NUM>). Such an option also provides for PDSCH rate matching around the symbols carrying the PDCCH.

In such options, there are potential issues with the degree of processing complexity at the base stations. For example, when the base station determines a successful LBT after the subframe boundary, it would perform another LBT to determine whether it may transmit at the next available starting time. In addition to the uncertainty of whether the subsequent LBT procedure would be successful, the base station would also start to precoding the data again for transmission over the remaining resource elements of the partial subframe. If, for example, the base station precodes the data again assuming a partial subframe beginning at symbol <NUM> of the first slot, but fails the subsequent LBT, which leaves the next transmit opportunity at symbol <NUM>. The base station would again begin a next LBT procedure and begin precoding the data again for the remaining resource elements from symbol <NUM> to the end of the partial frame. As such, several series of precoding and re-precoding, which entails processes such as grouping coded bits of the data into code blocks, assembling the code blocks into transport blocks, modulating the transport blocks and then precoding the transmission packets.

Moreover, when rate matching is applied which shifts transport blocks over different resource blocks (RBs), the complexity increases again, as different precoding is often employed over difference RBs. Accordingly, various aspects of the present disclosure are directed to reducing the complexity of base station processing while maintaining flexibility of different starting points in downlink initial partial subframes.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The example blocks will also be described with respect to gNB <NUM> as illustrated in <FIG> is a block diagram illustrating gNB <NUM> configured according to one aspect of the present disclosure. gNB <NUM> includes the structure, hardware, and components as illustrated for eNB <NUM> of <FIG>. For example, gNB <NUM> includes controller/processor <NUM>, which operates to execute logic or computer instructions stored in memory <NUM>, as well as controlling the components of gNB <NUM> that provide the features and functionality of gNB <NUM>. gNB <NUM>, under control of controller/processor <NUM>, transmits and receives signals via wireless radios 1100a-t and antennas 234a-t. Wireless radios 1100a-t includes various components and hardware, as illustrated in <FIG> for gNB <NUM>, including modulator/demodulators 232a-t, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, and TX MIMO processor <NUM>.

At block <NUM>, a base station detects a successful LBT procedure at a first transmission start point after a subframe boundary. The LBT procedure is performed by the base station over a shared spectrum. For example, when preparing for transmissions, the base station, such as gNB <NUM>, under control of controller/processor <NUM>, executes LBT logic <NUM>, stored in memory <NUM>. The execution environment of LBT logic <NUM> triggers gNB <NUM> to perform an LBT procedure. When gNB <NUM> detects that the LBT procedure has been successful, it may secure the channel.

At block <NUM>, the base station precodes a first block of data for transmission to a UE over available transmission resource elements in an initial partial subframe from the first transmission start point. For example, gNB <NUM>, under control of controller/processor <NUM>, assembles coded bits into code blocks, transport blocks, modulates the transport blocks, using the componentry with wireless radios 1100a-t, and then precodes the data, through execution of precoder <NUM>, stored in memory <NUM>, in preparation for transmission.

At block <NUM>, the base station punctures a set of resource elements of the available transmission resource elements uniformly over time and frequency of the initial partial subframe. As preparation for transmission when the network is configured for partial subframe transmissions, the base station, such as gNB <NUM>, under control of controller/processor <NUM>, executes partial subframe (SF) logic <NUM>, stored in memory <NUM>. The execution environment of partial SF logic <NUM> allows gNB <NUM> to monitor transmissions for any partial subframe opportunities. With the available set of resources remaining in the subframe making up the initial partial subframe, the execution environment of partial SF logic would allow gNB <NUM> to puncture a set of resource elements in a pattern to reduce the overall number of resource elements that may be used for downlink transmissions (e.g., PDSCH resource elements). The execution environment of partial SF logic <NUM> provides for gNB <NUM> to select a pattern for puncturing that may include accommodation for the locations of various control signals, such as channel state information (CSI) reference signals (CSI-RS), CRS, DMRS, and the like. Moreover, under certain transmission modes, such as transmission modes that support space frequency block coding (SFBC), the pattern selected by gNB <NUM> may be grouped by pairs or in groups of <NUM>, so as to preserve the SFBC grouping in the downlink transmissions.

Because downlink mapping in LTE and other OFDM RATs maps frequency first and then time, puncturing only a few OFDM symbols at the beginning of the initial partial subframe may cause some code blocks to be full lost, which may result in no possibility of recovering enough to decode the associated transport blocks. Thus, the systematic <NUM>-dimensional interleaved puncturing, after which the remaining tones of the partial subframe are compressed for transmission may allow for the possibility of decoding some transport block, as the code blocks may be punctured over both frequency and time may allow the punctured information to be recovered via parity checks or other such error checking procedures. At block <NUM>, the base station transmits the precoded first block of data over the available transmission resource elements to the UE. For example, gNB <NUM> would transmit the precoded first block of data using the available transmission REs via wireless radios 1100a-t and antennas 234a-t.

<FIG> is a block diagram illustrating a resource block (RB) <NUM> communicated between a base station <NUM> and UE <NUM> configured according to one aspect of the present disclosure. As noted above, when LBT is successful after a subframe boundary and downlink communication between base station <NUM> and UE <NUM> occurs via an initial partial subframe, uniform puncturing may be used to reduce the number of resources available for PDSCH while maintaining the precoding of the available transmission resource elements within the same RB, RB <NUM>. In the illustrated example, downlink transmission may start at the fourth symbol. The resource elements identified with an 'X' have been punctured, thus, reducing the number of resource elements available for PDSCH. The pattern of resource elements punctured in RB <NUM> have been selected to avoid the locations of any reference signals, such as CSI-RS, CRS, DMRS, and the like. The set of resource elements remaining for PDSCH may be compressed within RB <NUM>, which allows base station <NUM> to maintain the same precoding originally determined for the full subframe downlink transmission.

<FIG> is a block diagram illustrating a RB <NUM> communicated between base station <NUM> and UE <NUM> configured according to another aspect of the present disclosure. In a special case of the uniform puncturing solution, the transmission mode supports SFBC transmissions. In such a special case, base station <NUM> selects a pattern that groups the punctured resource elements in pairs across time and frequency. In such a pattern, the punctured resources avoids the SFBC groupings, as noted above.

It should be noted that with the uniform puncturing aspects for downlink initial partial subframes configured according to the various aspects of the present disclosure, there is no necessity to update or continue to precode the data as a downlink transmission starting point may change based on LBT failure, data preparation, or the like. For example, with transmission mode <NUM> or <NUM>, precoding of transmission data occurs on a per-RB basis. Thus, each RB in transmission mode <NUM> (e.g.,) has a different precoding mechanism. The receiving UEs are unaware of this precoding of the transmitted data, instead relying on analysis of the DMRS received first from the base station. The UE would estimate the DMRS channel and use that channel estimation to determine the precoding that has been used both with the DMRS and the transmitted data.

If the base station were to, instead, use a rate matching to prepare the data for transmission over the fewer available resource elements of the initial partial subframe, each time the starting point may change, the base station would re-precode all of the data for the new number of resource elements available for PDSCH. When rate matching, the position of the REs for the underlying transmission are no longer fixed to the RB. REs may be split across multiple RBs in order to accommodate the transmission. Therefore, not only would the base station using rate matching continue to re-precode data as the starting point changes, but the base station would use different precoding for the different RBs. The resulting complexity in such scenarios would increase greatly for the base stations. In contrast, the uniform puncturing of resource elements to reduce the number of REs available for transmission in the initial partial subframe, the same precoding would be applicable across the transmitted data in the same RB.

Additional aspects of the present disclosure are directed to identifying additional starting points for downlink transmission in initial partial subframes. In such aspects, the PDCCH points to the start of one or more short PDSCH in the partial subframe. The PDSCH would be based on the short PDSCH transmissions defined in the standards discussions of short TTIs. Short TTIs all for multiple PDSCH transmissions in the same partial subframe with different start positions. The different starting positions may be defined based on the associated short TTI and signaled in the PDCCH with multiple grants. The UE would monitor for PDCCH with regular DCI when control transmission starts in the first symbol of the first slot of the full subframe (e.g., symbol <NUM>), while the UE would monitor for PDCCH with the new DCI formats (which may indicate short PDSCH-related information) when control transmission starts in the first symbol of the second slot of the full subframe (e.g., symbol <NUM>). The UE may receive multiple PDCCHs for the short PDSCH.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The example blocks will also be described with respect to UE <NUM> as illustrated in <FIG> is a block diagram illustrating UE <NUM> configured according to one aspect of the present disclosure. UE <NUM> includes the structure, hardware, and components as illustrated for UE <NUM> of <FIG>. For example, UE <NUM> includes controller/processor <NUM>, which operates to execute logic or computer instructions stored in memory <NUM>, as well as controlling the components of UE <NUM> that provide the features and functionality of UE <NUM>. UE <NUM>, under control of controller/processor <NUM>, transmits and receives signals via wireless radios 1200a-r and antennas 252a-r. Wireless radios 1200a-r includes various components and hardware, as illustrated in <FIG> for UE <NUM>, including modulator/demodulators 254a-r, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, and TX MIMO processor <NUM>.

At block <NUM>, a UE monitors for a downlink grant from a serving base station in a first symbol of a first slot of a subframe. For example, UE <NUM>, under control of controller/processor <NUM>, monitors signals received via antennas 252a-r and wireless radios 1200a-r to detect downlink grants from a serving base station. With the network configured for transmissions over partial subframes, UE <NUM>, under control of controller/processor <NUM>, would also execute partial SF logic <NUM>, stored in memory <NUM>. The execution environment of partial SR logic <NUM> allows for UE <NUM> to monitors transmissions for transmission opportunities that may be using a partial subframe.

At block <NUM>, a determination is made by the UE whether a downlink grant was received at the first symbol of the first slot. As downlink grants may be detected by UE <NUM>, the execution environment of partial SF logic <NUM> provides for monitoring when such downlink grants arrive in order to determine whether the downlink transmissions will be full subframe or partial subframe. If so, then, at block <NUM>, the UE receives downlink data from the serving base station over a set of downlink transmission resources of the full subframe. If the downlink grant is detected by UE <NUM> in the first symbol of the first slot of the subframe, the entire subframe may be scheduled for downlink transmissions.

At block <NUM>, if the UE fails to detect the downlink grant in the first symbol of the first slot at block <NUM>, the UE monitors for a plurality of downlink grants from the serving base station in a first symbol of a second slot of the subframe. The execution environment of partial SF logic <NUM> allows for UE <NUM> to monitor for downlink grants in subsequent symbols of the subframe (e.g., the first symbol of the second slot) even when a downlink grant was not received in the first symbol of the first slot. A determination is made, at block <NUM>, whether the UE detects the plurality of downlink grants. Within the execution environment of partial SF logic <NUM>, UE <NUM> may determine if signals received in the first symbol of the second slot are several downlink grants. If not, then the UE will continue monitoring for grants at the next subframe, beginning again at block <NUM>. Otherwise, if the plurality of downlink grants are detected at the first symbol of the second slot of the subframe, then, at block <NUM>, the UE receives downlink data from the serving base station over the set of downlink transmission resources associated with each of the plurality of grants. When received as an initial partial subframe, the PDCCH containing downlink grants received by UE <NUM> in the second slot may direct UE <NUM> for each of the short PDSCH opportunities and receive the downlink data over the short PDSCH.

With the increased numbers of transmission opportunities with the initial partial subframe, acknowledgement information, e.g., acknowledgement (ACK) and negative acknowledgement (NACK), for each of the short PDSCH may be multiplexed and sent by the UE back to the base station. Such multiplexing may include simply aggregating acknowledgement information or may include processing the acknowledgement information (e.g., performing an AND function on the ACK/NACK) which may allow the UE to report a combined acknowledgement information using fewer resources.

It should be noted that the number of HARQ processes may be increased in certain alternative aspects in order to achieve peak rates.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The blocks of <FIG> will also be described with respect to the block diagram of <FIG> and with regard to UE <NUM> as detailed in <FIG>. <FIG> is a block diagram illustrating a base station <NUM> and a UE <NUM>, such as detailed in <FIG>, configured according to aspects of the present disclosure. At block <NUM>, a UE receives a first uplink configuration associated with uplink transmission for a full subframe and a second uplink configuration associated with uplink transmission for a partial subframe. The present aspect defines a PUSCH transmission ending partial subframe, ending in symbol <NUM>/<NUM> of the first slot of a subframe. The first and second uplink configurations provide for uplink control information (UCI) rate matching, for full subframe transmission and with new resources defined based on one slot transmission for partial subframe transmission. For example, base station <NUM> in communication stream <NUM> transmits the first and second uplink configurations including the UCI rate matching information at block <NUM>. UE <NUM> receives these uplink configurations and stores them in memory <NUM> at UL configurations <NUM> The configurations may include different beta factors for configuring full subframe and partial subframe transmissions. Beta factors (e.g., beta offset, ACK, CQI, and RI) correspond to specific dB values for UE <NUM> to transmit the uplink so that the base station may differentiate between PUSCH data, and ACK/CQI/RI transmissions.

At block <NUM>, the UE determines the transmission status of an ending transmission of an ending uplink subframe. The transmission status describes whether the ending transmission will be for a full subframe duration or a partial subframe duration. The execution environment of partial SF logic <NUM> allows UE <NUM> to determine whether the transmission status is for a full subframe duration or a partial subframe. At block <NUM>, the determination is made whether the transmission status is for a full subframe. If so, then at block <NUM>, the UE transmits the ending transmission according to the first uplink configuration. When the ending uplink transmission is for a full subframe, such as at subframe <NUM>, the beta parameters for full subframe transmission are used by UE <NUM> to configure the transmissions, so that base station <NUM> may be able to differentiate that transmitted data. UE <NUM> would then transmit the ending transmission using the uplink configuration stored at UL configurations <NUM> associated with the first uplink configuration. UE <NUM> would transmit via wireless radios 1200a-r and antennas 252a-r.

When the transmission status is not for a full subframe, then, at block <NUM>, the UE transmits the ending transmission according to the second uplink configuration. Thus, for partial subframe ending transmissions, such as at subframe <NUM>, the second uplink configuration will use the beta values for partial subframes. For the ending of the uplink transmissions, UE <NUM>, within the execution environment of partial SF logic <NUM>, would stop transmitting at symbol <NUM>, at <NUM>, of Slot <NUM> of subframe <NUM>.

It should be noted that, in additional or alternative aspects, one bit may be used from the multi-TTI grant to indicate whether the last subframe is full or partial subframe. Alternatively, one bit may be used in the common PDCCH (CPDCCH) to indicate whether the last subframe is full or partial subframe. Additionally, SRS can be configured for the last symbol of the end partial subframe. Each such additional aspects may be transmitted with control information at block <NUM>.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The blocks of <FIG> will also be described with respect to the block diagram of <FIG> and with regard to UE <NUM> as detailed in <FIG>. At block <NUM>, a UE receives downlink control information (DCI) identifying an uplink transmission start in a second slot of a subframe. For example, at transmission stream <NUM>, base station <NUM> transmits the DCI at block <NUM>. UE <NUM> receives the DCI via antennas 252a-r and wireless radios 1200a-r and stores the downlink control information, including the identification of the uplink transmission start at DCI <NUM>, stored in memory <NUM>. With operations including potential partial subframe transmissions, UE <NUM>, under control of controller/processor <NUM>, executes partial SF logic <NUM>. The execution environment of partial SF logic <NUM> allows UE <NUM> to monitor for partial subframe transmission opportunities.

At block <NUM>, the UE further receives an uplink configuration for transmission over a partial subframe. The uplink configuration may also be received together or separately at block <NUM>. UE <NUM> receives the uplink configuration via antennas 252a-r and wireless radios 1200a-r and, under control of controller/processor <NUM>, stores the uplink configuration at UL configurations <NUM>. As indicated above, beta parameters allow UE <NUM> to configure transmission of the uplink over the partial subframe in a manner that may be differentiated by the receiving base station. At block <NUM>, the UE transmits the uplink data over the partial subframe in the second slot according to the uplink configuration. For example, within the execution environment of partial SF logic <NUM>, UE <NUM> may detect the beginning symbol for its uplink transmission at <NUM> of slot <NUM> of subframe <NUM>. UE <NUM> would begin transmission via wireless radios 1200a-r and antennas 252a-r on the initial partial subframe of slot <NUM> and continue to the boundary of subframe <NUM>.

The mode of operation described in <FIG> represents a scheduled mode aspect, in which the DCI indicates to UE <NUM> that uplink transmissions start in the second slot (slot <NUM>) for an uplink initial partial subframe (subframe <NUM>). In such scheduled mode operation, the new UCI mapping, stored at UL configurations <NUM>, including the partial subframe beta parameters are communicated for UE <NUM>.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The blocks of <FIG> will also be described with respect to the block diagram of <FIG> and with regard to UE <NUM> as detailed in <FIG>. At block <NUM>, a UE receives an uplink grant identifying an uplink transmission over a full length of a subframe. With operations including potential partial subframe transmissions, UE <NUM>, under control of controller/processor <NUM>, executes partial SF logic <NUM>. The execution environment of partial SF logic <NUM> allows UE <NUM> to monitor for partial subframe transmission opportunities. Thus, the uplink grant received, at block <NUM>, at UE <NUM> via antennas 252a-r and wireless radios 1200a-r, indicates a full subframe transmission.

At block <NUM>, the UE detects a failure of an LBT procedure for transmission over the full length of the subframe. When UE <NUM> receives the uplink grant, at block <NUM>, because the spectrum is shared, it will first perform an LBT, by executing, under control of controller/processor <NUM>, LBT logic <NUM>, stored in memory <NUM>, to secure the channel. Even though UE <NUM> has been scheduled for a full subframe uplink transmission, the failed LBT, at <NUM>, causes UE <NUM>, within the execution environment of partial SF logic <NUM>, to back off and miss the opportunity for the full transmission.

At block <NUM>, the UE detects success of a next LBT procedure at a subsequent symbol of the subframe. Because UE <NUM> is allowed initial partial subframe for uplink transmissions, UE <NUM>, within the execution environment of partial SF logic <NUM>, would not have to back off transmissions for the entirety of subframe <NUM>. Therefore, at the next available opportunity, symbol <NUM>, UE <NUM> would perform another LBT procedure, through execution of LBT logic <NUM>, to secure the channel. For example, UE <NUM> may secure the channel for uplink transmission at symbol <NUM>, symbol <NUM>, or the like.

At block <NUM>, the UE transmits uplink data in a starting symbol of the subframe after the success of the next LBT procedure. Once UE <NUM> secures the channel, it may begin transmission via wireless radios 1200a-r and antennas 252a-r, in the next available symbol <NUM> of the remaining initial partial subframe, of subframe <NUM>. In this semi-scheduled mode, UE <NUM> may, through the execution environment of partial SF logic <NUM>, either re-perform rate matching to account for the smaller number of resource elements or symbols available for transmission or may perform puncturing of the first half of the original transmission scheduled, for which the channel had not yet been secured.

Prior to transmitting the uplink data, UE <NUM> would transmit a DMRS. For example, UE <NUM>, under control of controller/processor <NUM>, executes DMRS generator <NUM>, stored in memory <NUM>. The execution environment of DMRS generator <NUM> allows UE <NUM> to generate the appropriate DMRS for the transmission. In an additional aspect, UE <NUM> may implicitly identify the starting symbol <NUM> for uplink transmission by selecting a particular cyclic shift of the DMRS. Thus, when UE <NUM> determines which symbol it will begin uplink transmissions, within the execution environment of DMRS generator <NUM>, UE <NUM> will select the cyclic shift and transmit the DMRS to base station <NUM> using the cyclic shift. Using such a semi-scheduled mode, UE <NUM> may either perform initial transmission or retransmission. Additionally, the semi-scheduled mode would not affect or change the reference subframe for category <NUM> LBT procedures.

<FIG> is a block diagram illustrating example blocks executed to implement one aspect of the present disclosure. The blocks of <FIG> will also be described with respect to the block diagram of <FIG> and with regard to gNB <NUM> as detailed in <FIG>. At block <NUM>, a base station sends an uplink grant to a served UE wherein the uplink grant identifies uplink transmission for a full length of a subframe. <FIG> provides the semi-scheduled mode from the perspective of base station <NUM>. With operations including potential partial subframe transmissions, gNB <NUM>, under control of controller/processor <NUM>, also executes partial SF logic <NUM>. The execution environment of partial SF logic <NUM> allows gNB <NUM> to monitor for partial subframe transmission opportunities.

At block <NUM>, the base station monitors for a DMRS transmitted by the UE. Because gNB <NUM> has scheduled UE <NUM> for full subframe transmission at block <NUM>, gNB <NUM> would only know that when UE <NUM> transmits by monitoring for the DMRS. At block <NUM>, a determination is made whether the DMRS has been sent in the first slot. gNB <NUM> receives signals via antennas 234a-t and wireless radios 1100a-t and decodes the signals through the components of wireless radios 1100a-t to determine whether the signals include a DMRS. If so, then at block <NUM>, the base station detects that the UE performs the uplink transmission in a first slot according to the original full subframe transmission. Otherwise, if the DMRS is not in the first slot, then, at block <NUM>, the base station determines that the UE performs the uplink transmission outside of the first slot. Within the execution environment of partial SF logic <NUM>, by detecting the DMRS in a location other than the first slot, gNB <NUM> would determine that UE <NUM> fell back to an uplink initial partial subframe with a starting symbol at a location other than the first slot.

It should be noted as above, in alternative aspects, gNB <NUM> may read the cyclic shift of the DMRS to determine which symbol <NUM> UE <NUM> will beginning uplink transmission.

gNB <NUM> may also detect through DMRS transmitted by UE <NUM> that it has successfully secured the channel with an LBT at <NUM>, and transmitted uplink data for the full subframe at subframe <NUM>. Therefore, after initially scheduling UE <NUM> for full subframe transmission at uplink grant <NUM>, base station <NUM> detects the full subframe transmission of UE <NUM> through detection of the DMRS in slot <NUM> of subframe <NUM>.

The functional blocks and modules in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof.

Claim 1:
A method of wireless communication, comprising:
receiving (<NUM>), at a user equipment, UE, from a serving base station, downlink control information identifying an uplink transmission start in a second slot of a subframe;
receiving (<NUM>), at the UE from the serving base station, an uplink configuration for transmission over a partial subframe, wherein the uplink configuration includes beta parameters for configuring partial subframe transmissions and wherein the beta parameters include beta offset, acknowledgement, ACK, channel quality indicator, CQI, rank indicator, RI, or a combination thereof; and
transmitting (<NUM>), by the UE, uplink data over the partial subframe in the second slot according to the uplink configuration.