Patent Description:
The present disclosure relates generally to wireless communication systems, and more particularly, to methods and apparatus for generating sequences and mapping cyclic shifts of the sequences to hypotheses for short burst transmissions, for example, in new radio (NR) technologies.

In some examples, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). In LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation or <NUM> network), a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with a number of central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., a new radio base station (NR BS), a new radio node-B (NR NB), a network node, <NUM> NB, eNB, Next Generation Node B (gNB), etc.). A base station or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit).

However, as the demand for mobile broadband access continues to increase, there exists a desire for further improvements in NR technology.

Document (<NPL>", 3RD Generation Partnership Project (3GPP)) discloses new base sequences with lower PAPR, and suggests using one base sequence with a different cyclic shift offset for different UEs and <NUM> different cyclic shifts for different values of ACK/NACK feedback.

Document (<NPL>", 3RD Generation Partnership Project (3GPP)) considers different aspects of <NUM> or <NUM> bit UCI in <NUM> symbol short PUCCH. A new CGS sequence for sequence based on short PUCCH for NR is proposed.

Document (<NPL>", 3RD Generation Partnership Project (3GPP)) is directed to support transmissions of uplink control information (UCI) using both short and long duration PUCCH formats in NR and discusses the outstanding design aspects of the <NUM>-symbol PUCCH format with <NUM> or <NUM> UCI bits. A set of CGS sequences satisfying the performance metrics, namely PAPR/CM and cross-correlation between different base sequence groups is proposed.

Document (<NPL>", 3RD Generation Partnership Project (3GPP)) discloses Computer Generated Sequences, CGS, with low PAPR used for <NUM> or <NUM> bits payload UCI transmission on <NUM> symbol short PUCCH.

Document (<NPL>", 3RD Generation Partnership Project (3GPP)) is directed to the design of <NUM>-symbol PUCCH for up to <NUM> bits based on the sequence selection (a. a Option <NUM>). Thereby, for short-PUCCH design, focusing on the multi-user multiplexing as the design target is not a proper approach. Instead, the design should be such that the coverage is improved and the PAPR and CM are kept as low as possible.

Independent claim <NUM> defines a method for wireless communication according to the claimed invention. Independent claims <NUM> and <NUM> define corresponding apparatus according to the claimed invention. Independent claim <NUM> defines the corresponding computer program according to the claimed invention.

Certain aspects provide a method for wireless communication by a transmitter. The method generally includes selecting a computer generated sequence (CGS) from a plurality of CGSs, determining, based on different values of uplink control information (UCI) and a first shift index assigned to the transmitter, a shift to apply to the CGS, and transmitting the selected CGS, with the determined shift applied, in a short physical uplink control channel (PUCCH) to indicate the UCI.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes a processor configured to select a computer generated sequence (CGS) from a plurality of CGSs; to determine, based on different values of uplink control information (UCI) and a first shift index assigned to the apparatus, a shift to apply to the CGS; and to transmit the selected CGS, with the determined shift applied, in a short physical uplink control channel (PUCCH) to indicate the UCI; and a memory coupled with the processor.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes means for selecting a computer generated sequence (CGS) from a plurality of CGSs; means for determining, based on different values of uplink control information (UCI) and a first shift index assigned to the apparatus, a shift to apply to the CGS; and means for transmitting the selected CGS, with the determined shift applied, in a short physical uplink control channel (PUCCH) to indicate the UCI.

Certain aspects provide a computer-readable medium including instructions. The instructions, when executed by a processor, cause the processor to perform operations generally including selecting a computer generated sequence (CGS) from a plurality of CGSs; determining, based on different values of uplink control information (UCI) and a first shift index assigned to an apparatus including the processor, a shift to apply to the CGS; and transmitting the selected CGS, with the determined shift applied, in a short physical uplink control channel (PUCCH) to indicate the UCI.

NR may support various wireless communication services, such as Enhanced mobile broadband (eMBB) services targeting wide bandwidth (e.g. <NUM> and wider) communications, millimeter wave (mmW) services targeting high carrier frequency (e.g. <NUM> and higher) communications, massive machine-type communications (mMTC) services targeting non-backward compatible machine-type communications (MTC) techniques, and/or mission critical services targeting ultra-reliable low latency communications (URLLC).

"LTE" refers generally to LTE, LTE-Advanced (LTE-A), LTE in an unlicensed spectrum (LTE-whitespace), etc. The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies.

<FIG> illustrates an example wireless network <NUM>, such as a new radio (NR) or <NUM> network, in which aspects of the present disclosure may be performed.

As illustrated in <FIG>, the wireless network <NUM> may include a number of BSs <NUM> and other network entities. A BS may be a station that communicates with UEs. Each BS <NUM> may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to a coverage area of a Node B and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and eNB, Node B, <NUM> NB, AP, NR BS, NR BS, gNB, or TRP may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in the wireless network <NUM> through various types of backhaul interfaces such as a direct physical connection, a virtual network, or the like using any suitable transport network.

A network controller <NUM> may be coupled to a set of BSs and provide coordination and control for these BSs. The BSs <NUM> may also communicate with one another, e.g., directly or indirectly via wireless or wireline backhaul.

A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a healthcare device, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, a robot, a drone, industrial manufacturing equipment, a positioning device (e.g., GPS, Beidou, terrestrial), or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices, which may include remote devices that may communicate with a base station, another remote device, or some other entity. Machine type communications (MTC) may refer to communication involving at least one remote device on at least one end of the communication and may include forms of data communication which involve one or more entities that do not necessarily need human interaction. MTC UEs may include UEs that are capable of MTC communications with MTC servers and/or other MTC devices through Public Land Mobile Networks (PLMN), for example. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, cameras, location tags, etc., that may communicate with a BS, another device (e.g., remote device), or some other entity. MTC UEs, as well as other UEs, may be implemented as Internet-of Things (IoT) devices, e.g., narrowband IoT (NB-IoT) devices.

For example, the spacing of the subcarriers may be <NUM> and the minimum resource allocation (called a 'resource block') may be <NUM> subcarriers (or <NUM>). Consequently, the nominal FFT size may be equal to <NUM>, <NUM>, <NUM>, <NUM> or <NUM> for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM> megahertz (MHz), respectively. For example, a subband may cover <NUM> (e.g., <NUM> resource blocks), and there may be <NUM>, <NUM>, <NUM>, <NUM> or <NUM> subbands for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, respectively.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using time division duplex (TDD). A single component carrier bandwidth of <NUM> may be supported. NR resource blocks may span <NUM> sub-carriers with a sub-carrier bandwidth of <NUM> over a <NUM> duration. Each radio frame may consist of <NUM> half frames, each half frame consisting of <NUM> subframes, with a length of <NUM>. Consequently, each subframe may have a length of <NUM>. Each subframe may indicate a link direction (e.g., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. UL and DL subframes for NR may be as described in more detail below with respect to <FIG>. Alternatively, NR may support a different air interface, other than an OFDM-based. NR networks may include entities such CUs and/or DUs.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., eNB, <NUM> Node B, Node B, transmission reception point (TRP), access point (AP)) may correspond to one or multiple BSs. NR cells can be configured as access cell (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover. In some cases DCells may not transmit synchronization signals-in some case cases DCells may transmit SS. NR BSs may transmit downlink signals to UEs indicating the cell type. Based on the cell type indication, the UE may communicate with the NR BS. For example, the UE may determine NR BSs to consider for cell selection, access, handover, and/or measurement based on the indicated cell type.

The ANC may include one or more TRPs <NUM> (which may also be referred to as BSs, NR BSs, Node Bs, <NUM> NBs, APs, gNBs, or some other term).

<FIG> illustrates example components of the BS <NUM> and UE <NUM> illustrated in <FIG>, which may be used to implement aspects of the present disclosure. As described above, the BS may include a TRP. One or more components of the BS <NUM> and UE <NUM> may be used to practice aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the operations described herein and illustrated with reference to <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 Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), etc. The data may be for the Physical Downlink Shared Channel (PDSCH), etc. The processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor <NUM> may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. For example, the TX MIMO processor <NUM> may perform certain aspects described herein for RS multiplexing.

For example, MIMO detector <NUM> may provide detected RS transmitted using techniques described herein. According to one or more cases, CoMP aspects can include providing the antennas, as well as some Tx/Rx functionalities, such that they reside in distributed units. For example, some Tx/Rx processings can be done in the central unit, while other processing can be done at the distributed units. For example, in accordance with one or more aspects as shown in the diagram, the BS mod/demod <NUM> may be in the distributed units.

The processor <NUM> and/or other processors and modules at the base station <NUM> may perform or direct the processes for the techniques described herein. The processor <NUM> and/or other processors and modules at the UE <NUM> may also perform or direct processes for the techniques described herein. The memories <NUM> and <NUM> may store data and program codes for the BS <NUM> and the UE <NUM>, respectively.

Regardless of whether a network access device implements part or all of a protocol stack, a UE may implement an entire protocol stack <NUM>-c (e.g., the RRC layer <NUM>, the PDCP layer <NUM>, the RLC layer <NUM>, the MAC layer <NUM>, and the PHY layer <NUM>).

The DL-centric subframe may also include a common UL portion <NUM>. The common UL portion <NUM> may sometimes be referred to as an UL burst, a common UL burst, an UL short burst, and/or various other suitable terms. The common UL portion <NUM> may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion <NUM> may include feedback information corresponding to the control portion <NUM>. Non-limiting examples of feedback information may include a hybrid automatic retransmission request (HARQ) acknowledgment (ACK) signal, a hybrid automatic retransmission request (HARQ) negative acknowledgment (NAK) signal, channel quality indicator (CQI) information, a scheduling request (SR), and/or various other suitable types of information. Short data, such as TCP ACK information, as well as reference signals, such as sounding reference signals (SRS), may also be conveyed. UL short bursts may have one or more OFDM symbols. The common UL portion <NUM> may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. In some cases, such information may be conveyed using shifted sequences transmitted on tones in the UL short burst region. Such shifted sequences have certain properties that may make them suitable for such applications and may be used for common pilot tones.

As illustrated in <FIG>, the end of the DL data portion <NUM> may be separated in time from the beginning of the common UL portion <NUM>. One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

<FIG> is a diagram <NUM> showing an example of an UL-centric subframe. The UL -centric subframe may include a control portion <NUM>. The control portion <NUM> may exist in the initial or beginning portion of the UL-centric subframe. The control portion <NUM> in <FIG> may be similar to the control portion described above with reference to <FIG>. The UL-centric subframe may also include an UL data portion <NUM>. The UL data portion <NUM> may sometimes be referred to as the payload of the UL-centric subframe. The UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS). In some configurations, the control portion <NUM> may be a physical DL control channel (PDCCH).

As illustrated in <FIG>, the end of the control portion <NUM> may be separated in time from the beginning of the UL data portion <NUM>. The UL-centric subframe may also include a common UL portion <NUM>. The common UL portion <NUM> in <FIG> may be similar to the common UL portion <NUM> described above with reference to <FIG>. As with the common UL portion <NUM> shown in <FIG>, the common UL portion <NUM> may include HARQ-ACK information (e.g., HARQ ACKs and/or HARQ NAKs), a scheduling request, information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

In accordance with one or more aspects of embodiments disclosed herein, various designs are provided for short burst channels (e.g., PUCCH and PUSCH), that allow for multiplexing various signals.

According to aspects of the present disclosure, for simultaneous transmission of two bits of hybrid automatic retransmission request acknowledgment (HARQ-ACK) information (i.e., two acknowledgments (ACKs), negative acknowledgments (NAKs), or a combination) and a scheduling request (SR), a UE may transmit a short PUCCH including uplink control information (UCI) of up to two bits. The UCI may include ACKs and/or NACKs of downlink transmissions (e.g., PDSCHs) that a UE has received from a serving cell, as well as an SR, i.e., an indication that the UE has additional information to transmit and needs uplink transmission resources to transmit that additional information.

In aspects of the present disclosure, a UE may transmit a short-PUCCH with UCI of <NUM> or more bits (e.g., with or without an SR) via selection of a cyclic shift of a sequence. That is, a UE may select a cyclic shift of a sequence (e.g., a computer generated sequence (CGS)) to convey two or more bits of information (e.g., an ACK/NACK and an SR, two ACK/NACKs, or two ACK/NACKs combined with an SR) and transmit the shifted sequence in a short-PUCCH.

According to aspects of the present disclosure, sequences are provided that maximize the shift distance between the shifted sequences for use in transmitting short PUCCHs. In the provided sequences, a base sequence with length N in frequency domain may be represented as X(<NUM>,. N-<NUM>), where X may be a low PAPR sequence, e.g., a Chu sequence or a CGS. For one bit of uplink control information (e.g., an ACK/NACK), the sequences may be chosen with a shift distance of N/<NUM> between the sequences. Without losing generality, the two sequences may be represented as X1 = X and X2 = X*exp(j*π*[<NUM>:N-<NUM>]).

<FIG> illustrates an exemplary mapping <NUM> of exemplary shifted sequences <NUM> and <NUM> (i.e., shifted versions of a base sequence) that may be used to convey one bit of information as described above, according to aspects of the present disclosure. As illustrated, the two sequences have exactly the same values <NUM>, <NUM>, <NUM>, and <NUM> on every other tone, while the other tones <NUM>, <NUM>, <NUM>, and <NUM> have opposite values in the two sequences. Thus, the exemplary sequences have an equivalent DMRS structure. Every other tone (i.e., the tones <NUM>, <NUM>, <NUM>, and <NUM>) may be used for channel estimation and noise estimation. In addition, the sequences may have identical demodulation performance as a coherent detection design, with an extra benefit that the transmitted symbols still have low peak-to-average-power-ratio (PAPR) properties. As illustrated, for one bit of ACK/NACK information (i.e., one bit that conveys either an ACK or a NACK, depending on the value of the one bit), a cyclic shift of L/<NUM> in the time domain may lead to sign alternative flipping in the frequency domain, where L is the sequence length.

Similarly to the sequences described above, for transmitting two bits of information, four sequences with a minimum shift distance of L/<NUM> are provided. In the four sequences, every fourth tone can be used as a DMRS tone. The base sequence may be a CGS, a Chu sequence, or any other low PAPR sequence.

<FIG> illustrates an exemplary mapping <NUM> of exemplary shifted sequences <NUM>, <NUM>, <NUM>, and <NUM> that may be used to convey two bits of information as described above, according to aspects of the present disclosure. As illustrated, the four sequences have the same values on every fourth tone <NUM> and <NUM>, while the other tones <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> have values that are each orthogonal to each other in each of the four sequences. With a minimum shift distance of L/<NUM>, every fourth tone (i.e., the tones <NUM> and <NUM>) can be used as a DMRS tone, e.g., for channel estimation and noise estimation. The base sequence may be CGS sequence, Chu sequence, or other low PAPR sequences. As illustrated, for two bits of ACK/NACK information (i.e., two bits that convey two ACKs, NACKs, or a combination of one ACK and one NACK, depending on the values of the two bits), a cyclic shift of L/<NUM> in the time domain may lead to orthogonal values in the frequency domain, where L is the sequence length.

According to aspects of the present disclosure, properties of the shifted sequences may be exploited to allow for enhanced receiver techniques. For sequence hypotheses having common tones with same (known) values, these tones may, in effect, be used as additional DMRS tones to enhance channel estimation. A receiver implementing such techniques may be considered a hybrid coherent/non-coherent receiver.

While aspects of the present disclosure are described in terms of transmitting one or two bits, the disclosure is not so limited, and aspects of the present disclosure may be used to transmit more than two bits.

According to aspects of the present disclosure, a same set of sequences (e.g., CGSs) may be used in short PUCCHs and long PUCCHs when either is used for transmission of one or more UCI bits on one PRB. That is, one set of sequences may be used to convey bits of UCI in both short PUCCHs and long PUCCHs.

In aspects of the present disclosure, different sets of sequences may be used in short PUCCHs and long PUCCHs when either is used for transmission of one or more UCI bits on one PRB.

According to aspects of the present disclosure, sequences used for conveying information in PUCCHs may be compared on one or more bases. For example, sequences may be compared based on maximum peak-to-average-power-ratio (PAPR), maximum cubic metric (CM), minimum PAPR, minimum CM, mean PAPR, mean CM (e.g., assuming at least 8x oversampling of the sequences by a receiver), and maximum cross-correlation.

In aspects of the present disclosure, maximum cross-correlation between base sequences may be evaluated for new NR sequences by applying all cyclic shift (CS) values of the new NR sequences.

According to aspects of the present disclosure, maximum cross-correlation between the provided base sequences for new NR and LTE (e.g., previously known) sequences may be evaluated by applying all cyclic shift (CS) values to LTE CGS for transmissions sent in one-PRB and two-PRB blocks, and applying all CS values to Zadoff-Chu (ZC) sequences for transmissions sent in blocks larger than two PRBs on up to <NUM> bandwidth, and considering all partial overlapping between the provided sequences and the LTE sequences.

Other examples for metrics of base sequences can include but are not limited to statistics of cross-correlation, such as mean cross-correlation, maximum cross-correlation, and standard deviation of the cross-correlation of the <NUM>th percentile sequences. Both Method <NUM>, using an n-sequence length equal to <NUM> (<NUM>*<NUM>), and Method <NUM>, based on R1-<NUM>, can be used to calculate the cross-correlation. In addition, timing misalignment with other values for oversampling can also be realized with Method <NUM>. Aperiodic cross-correlation for different timing arrivals can also be used as a metric for base sequences.

Modulation type and error vector magnitude (EVM) of received signals using the provided sequences and previously known sequences may also be examples of metrics for comparison of base sequences.

In aspects of the present disclosure, receiver complexity may be used as a performance metric for comparison of base sequences.

According to aspects of the present disclosure, LTE CGS (e.g., CGS used in current LTE communications) are used as a reference for performance comparison with sequences disclosed herein.

In aspects of the present disclosure, using a same set of sequences for short PUCCHs and long PUCCHs may simplify the design (e.g., of the communications protocol) and also save CGS look-up-tables (LUTs). That is, use of the same set of sequences for short PUCCHs and long PUCCHs allows usage of one look-up-table for both short and long PUCCHs conveying a given amount (e.g., two bits) of data, instead of one look-up-table for short PUCCHs conveying that amount of data and a second look-up-table for long PUCCHs conveying that amount of data.

According to aspects of the present disclosure, a same set of sequences can be used for short PUCCHs and long PUCCHs, as long as each of the sequences in the set has a constant modulus in frequency domain. By using a sequence that has a constant modulus in frequency domain, different ACK/NACK/SR hypotheses and users may be separated with cyclic shifts, and therefore, <NUM> sequences may be enough to support different cells. Otherwise, if different sets of sequences for short PUCCH that are not constant modulus in frequency are used, then it may be desirable to define one sequence for each hypothesis or user per cell.

In aspects of the present disclosure, when a constant phase rotation is applied to all elements of one sequence, the resulting sequence may be considered equivalent to the original sequence, because the elements of the resulting sequence will have exactly the same PAPR and cross-correlation properties as the elements of the original sequence. Furthermore, a cyclic shifted version of a CGS may be treated as an equivalent sequence to the original CGS, because the cyclic shifted version and the original CGS have the same PAPR and same cross-correlation with other sequences. For example, any QPSK based CGS with a cyclic shift equal to N/<NUM>*i in time domain (i=<NUM>, <NUM>, <NUM>, or <NUM>, where N is the length of the sequence in time domain) will give another QPSK based CGS which may be treated as an equivalent sequence.

According to aspects of the present disclosure, in order to remove duplicate sequence definitions, CGSs may be converted to a same reference symbol for the first element of each sequence, e.g., -<NUM>.

In aspects of the present disclosure, a cyclic shifted version of a CGS may be considered equivalent to the original CGS. That is, because cyclic shifting is used to convey bits of data, cyclically shifting a sequence that is a cyclic shifted version of a CGS is equivalent to cyclically shifting the CGS, and conveys the same quantity of data.

<FIG> illustrates example operations <NUM> for wireless communications by a transmitter, in accordance with aspects of the present disclosure. The operations <NUM> may be performed by a UE, such as UE <NUM>, shown in <FIG> and <FIG>. One or more of the components shown in <FIG> may be used in performing the operations <NUM>.

Operations <NUM> begin, at block <NUM>, by the transmitter selecting a computer generated sequence (CGS), from a plurality of CGSs. For example, UE <NUM>, shown in <FIG>, selects a CGS (e.g., from a look-up-table) consisting of the set of values √<NUM>/<NUM> *[(-<NUM>-j), (<NUM>+j), (-<NUM>-j), (-<NUM>-j), (-<NUM>-j), (-<NUM>+j), (-<NUM>-j), (<NUM>-j), (<NUM>+j), (<NUM>+j), (<NUM>+j), (-<NUM>-j)] from a plurality of CGSs (e.g., the sets of CGSs described below with reference to <FIG> and <FIG>).

At block <NUM>, operations <NUM> continue with the transmitter determining, based on different values of uplink control information (UCI) and a first shift index assigned to the transmitter, a shift to apply to the CGS. Continuing the example from above, the transmitter determines a shift of seven to apply to the CGS, based on a first shift index of one assigned to the transmitter and an assignment of a shift of six to a value of UCI that the transmitter is transmitting.

Operations <NUM> continue at block <NUM> with the transmitter transmitting the selected CGS, with the determined shift applied, in a short physical uplink control channel (PUCCH) to indicate the UCI. Continuing the example from above, the transmits the CGS selected in block <NUM> with the determined shift of seven (that is, the shifted sequence is √<NUM>/<NUM> *[(<NUM>-j), (<NUM>+j), (<NUM>+j), (<NUM>+j), (-<NUM>-j), (-<NUM>-j), (<NUM>+j), (-<NUM>-j), (-<NUM>-j), (-<NUM>-j), (-<NUM>+j), (-<NUM>-j)] in a short PUCCH to indicate the UCI (e.g., to convey the UCI to a base station).

According to aspects of the present disclosure, the PAPR of LTE CGS sequences may not be optimized. A computer search with QPSK sequences for <NUM> RB may obtain a set of CGS sequences, as shown herein with reference to <FIG> and <NUM>.

In aspects of the present disclosure, elements ru,v(n) of a CGS may be calculated according to the formula: <MAT> where:.

Sequences calculated in this manner may be represented by tables of the values of x(n).

<FIG> and <FIG> illustrate a table <NUM> of values of x(n) for sequences for use in PUCCH, according to the claimed invention. In the table, each row is for a different sequence, a first column <NUM> is an index to the sequence, a second column <NUM> shows the formula for calculation of the terms in the header row and the values of x(n) for each sequence in the other rows, a third column <NUM> shows CM in decibels for each sequence, and a fourth column <NUM> shows PAPR in decibels for each sequence.

The tables below summarize the PAPR and cross-correlation comparisons of the provided CGSs with previously known LTE sequences. For mean PAPR, the provided sequences outperform LTE sequences by <NUM> dB. For maximum PAPR, the provided sequences outperform LTE sequences by <NUM> dB. The cross-correlation of the provided sequences is also better than the cross-correlation of LTE sequences.

<FIG> is a table <NUM> showing additional sequences, according to aspects of the present disclosure. As with the sequences illustrated in <FIG>, the sequences are represented by values of x(n) to be used in the equation r(n) = u * exp(j*π*x(n)/<NUM>). Thus, the values in the row <NUM> are representative of a sequence of the form √<NUM>/<NUM> *[(-<NUM>-j), (<NUM>-j), (<NUM>-j), (-<NUM>+j), (<NUM>+j), (<NUM>-j), (<NUM>-j), (<NUM>+j), (-<NUM>-j), (<NUM>-j), (-<NUM>-j), (-<NUM>-j)].

<FIG> are exemplary graphs of curves illustrating the performance of the provided sequences and previously known sequences, according to aspects of the present disclosure.

<FIG> is a graph <NUM> showing curves illustrating self-cross-correlation of the provided sequences and LTE sequences mentioned. The curve <NUM> shows a cumulative distribution function (CDF) of the self-cross-correlation of the provided sequences, while the curve <NUM> shows a CDF of the self-cross-correlation of previously known LTE sequences. As illustrated, the self-cross-correlation of the provided sequences are nearly identical to the self-cross-correlation of previously known LTE sequences.

<FIG> is a graph <NUM> showing curves illustrating cross-correlation of LTE sequences with the provided sequences. The curve <NUM> shows a CDF of the cross-correlation of a provided sequence of length twelve (i.e., N=<NUM>) with the previously known LTE sequence of length twelve, while the curve <NUM> shows a CDF of the cross-correlation of the LTE sequence with itself. As illustrated, the cross-correlation of the provided sequence with the LTE sequence is a close approximation of the cross-correlation of the LTE sequence with itself.

<FIG> is a graph <NUM> showing curves illustrating relationships between PAPR and bit error rate (BER) of the disclosed sequences and the previously known LTE sequences. The curve <NUM> shows a CDF of bit error rate (BER) experienced by a receiver receiving the disclosed sequence when transmitted by a transmitter transmitting a provided sequence and other signals at various PAPR to the other signals. The curve <NUM> shows a CDF of BER experienced by a receiver receiving an LTE sequence when transmitted by a transmitter transmitting the sequence and other signals at various PAPR to the other signals. As illustrated, the provided sequences are received with lower bit error rates at lower PAPR than the LTE sequences.

<FIG>, which are useful for an understanding of the invention, are tables <NUM>, <NUM>, <NUM>, and <NUM> of exemplary values of x(n) for sequences for use in PUCCHs, according to aspects of the present disclosure. In the tables, each row is for a different sequence. As above in <FIG>, the sequences are represented by values of x(n) to be used in the equation r(n) = u * exp(j*π*x(n)/<NUM>).

<FIG> is a table <NUM> of exemplary values of x(n) for sequences having a length of six for use in PUCCH, according to aspects of the present disclosure. In the table, a first column <NUM> is an index to the table of sequences, and a second column <NUM> shows the values of x(n) for each of the sequences.

<FIG> is a table <NUM> of exemplary values of x(n) for sequences having a length of twelve for use in PUCCH, according to aspects of the present disclosure. In the table, a first column <NUM> is an index to the table of sequences, and a second column <NUM> shows the values of x(n) for each of the sequences.

<FIG> is a table <NUM> of exemplary values of x(n) for sequences having a length of eighteen for use in PUCCH, according to aspects of the present disclosure. In the table, a first column <NUM> is an index to the table of sequences, and a second column <NUM> shows the values of x(n) for each of the sequences.

<FIG> is a table <NUM> of exemplary values of x(n) for sequences having a length of twenty-four for use in PUCCH, according to aspects of the present disclosure. In the table, a first column <NUM> is an index to the table of sequences, and a second column <NUM> shows the values of x(n) for each of the sequences.

According to aspects of the present disclosure, the use of sequences to transmit ACK/NACK bits may be generalized to other numbers of bits. If Ns is the sequence length and Nb is the number of bits (e.g., ACK/NACK bits) to be transmitted, then a minimum shift distance, ds, may be calculated as <MAT>.

When compared with other sequence based designs, the disclosed techniques have the benefits of maximizing the minimum shift distance between hypotheses as well as the ability of coherent detection.

With sequence based design as disclosed herein, up to <NUM> UEs may be multiplexed in one period, with each UE transmitting <NUM> bit of UCI, or <NUM> UEs may be multiplexed, with each UE transmitting <NUM> bits of UCI. When UEs are multiplexed together, it may be desirable to randomize the mapping from ACK/NACK hypothesis to shifts so that one hypothesis doesn't face consistent interference from the same hypothesis from another UE.

According to aspects of the present disclosure, randomization of the mapping from ACK/NACK hypothesis to shifts may be done by combining two techniques. A first technique may include different shift scheduling from slot to slot by a BS (e.g., an eNB, a gNB). For example, a UE may be assigned (e.g., by a BS serving a cell to which the UE is connected) with shifts <NUM>, <NUM>, <NUM>, and <NUM> in one slot, and then <NUM>, <NUM>, <NUM>, and <NUM> in another slot. A second technique for the randomization is by randomizing the relative mapping orders of the ACK/NACK hypothesis within the assigned shifts. The mapping order may be determined by a pre-determined pattern based on the one of more of the parameters including first shift index, the slot index, and the symbol index.

In aspects of the present disclosure, a technique for randomizing the relative mapping orders may be determined as in the following example. Let <MAT> be the first cyclic shift index assigned by eNB to the UE for the symbol number l and the slot number ns. Then the UE may derive the ith cyclic shift indices according to the flowing formula: <MAT> where <MAT>.

The total assigned shifts are <NUM>Nb. For example, with <NUM> bits, if <MAT>, the assigned shifts are {<NUM>, <NUM>, <NUM>, <NUM>}.

According to aspects of the present disclosure, for one bit of ACK/NACK information, the NACK hypothesis (<NUM>) may be mapped to the j<NUM>th cyclic shifts <MAT> randomly, where j<NUM> (ns,l) is determined by <MAT> where the pseudo-random sequence c(i) is defined by clause <NUM> in 3GPP TS36. <NUM> ("Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation," which is publicly available). The pseudo-random sequence generator may be initialized with <MAT>, where <MAT> is either configured by higher layer, set as cell ID, or is a function of UE RNTI, and <MAT> is the number of symbols in a short PUCCH region (i.e., a region of time and frequency resources). The ACK hypothesis (<NUM>) may be mapped to the other shift index that is j<NUM> th cyclic shifts <MAT>, where j<NUM>(ns, /) is determined by <MAT>.

In aspects of the present disclosure, for two bits of ACK/NACK information, the NACK/NACK hypothesis (<NUM>) may be mapped to the j<NUM> th cyclic shifts <MAT>, where j<NUM>(ns,l) is determined by <MAT> where the pseudo-random sequence c(i) is defined by clause <NUM> in TS36. The pseudo-random sequence generator may be initialized with <MAT>, where <MAT> is either configured by higher layer, set as a cell ID, or is a function of UE RNTI. The ACK ACK hypothesis (<NUM>) may be mapped to a shift index with largest shift distance to NACK NACK hypothesis, that is j<NUM> th cyclic shifts <MAT>, where j<NUM>(ns,l) is determined by <MAT>.

The NACK ACK hypothesis (<NUM>) may be mapped to one of the remaining two shifts j<NUM> th cyclic shifts <MAT>, where j<NUM>(ns,l) is determined by <MAT>.

The ACK NACK hypothesis (<NUM>) may be mapped to the shift index with largest shift distance to NACK ACK hypothesis, that is j<NUM> th cyclic shifts <MAT>, where j<NUM>(ns,l) is determined by <MAT>.

One example is illustrated in the following table, where <NUM> denotes an ACK and <NUM> denotes a NACK. As can be seen from the example, the same shift is mapped to a different ACK/NACK hypothesis in each of the different slots. Therefore, its neighbor hypothesis will also be different. The interference faced by a UE for transmission of a given hypothesis in different slots may be randomized.

According to aspects of the present disclosure, a similar concept may be applied to <NUM>-symbol short PUCCHs with up to <NUM> bits as well. In that case, different short PUCCH symbols will use different mapping due to the variation of symbol index l in the formula. Furthermore, the first shift index in different symbols or different slots may be derived from the first shift index assigned in the first symbol or the first slot. That is, a shift hopping among symbols or slots may be used on top of the random mapping between shift index and ACK/NACK hypothesis. In some scenarios, all the shift indices used by the UE may be assigned by a BS (e.g., an eNB or a gNB), rather than derived by the UE from the first shift index.

According to aspects of the present disclosure, a similar concept may be applied to <NUM> or <NUM>-symbol short PUCCHs with more than <NUM> bits as well. For more than <NUM> bits of UCI, the shift index may be derived by the UE based the first shift index, or it may be assigned by the eNB. The mapping of from the hypothesis to the shift index may also be randomized based on a pseudo-random sequence as a function of first shift index, the symbol index, and the slot index.

According to aspects of the present disclosure, different control resource sets (CORESETs) may use different PUCCH resource sets. That is, a UE configured to use different CORESETs for sending control information may use different PUCCH resource sets associated with the different CORESETs, when transmitting PUCCHs as described herein.

In aspects of the present disclosure, a PUCCH with up to <NUM> bits of UCI and a PUCCH with more than <NUM> bits of UCI in either short or long duration PUCCHs use different sets. Thus, according to aspects of the present disclosure, a UE may be configured with <NUM> resource sets for: short PUCCHs conveying <NUM> or <NUM> bits of UCI, short PUCCHs conveying <NUM> or more bits of UCI, long PUCCHs conveying <NUM> or <NUM> bits of UCI, and long PUCCHs conveying <NUM> or more bits of UCI.

According to aspects of the present disclosure, default values of the starting symbol and ending symbol for long PUCCH may derived based on information received in system information blocks (SIBs).

In aspects of the present disclosure, default values of the starting symbol and ending symbol (e.g., a number of symbols) may be semi-statically configured for a UE via RRC signaling.

According to aspects of the present disclosure, default starting and/or ending symbols (e.g., as mentioned above) for both short PUCCH and long PUCCH may be dynamically overridden in downlink control information (DCI).

Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more. " For example, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from the context to be directed to a singular form. Unless specifically stated otherwise, the term "some" refers to one or more. " That is, unless specified otherwise, or clear from the context, the phrase, for example, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, for example the phrase "X employs A or B" is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B.

Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory), flash memory, phase change memory, ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof.

For example, instructions for performing the operations described herein and illustrated in the appended figures.

Claim 1:
A method (<NUM>) for wireless communications by a transmitter, comprising:
selecting (<NUM>) a computer generated sequence, CGS, from a plurality of CGSs, wherein selecting (<NUM>) the CGS comprises:
obtaining a sequence index, u (<NUM>), of the CGS; and
selecting a sequence (<NUM>) of exponent values, x(n), from:

<TAB>

based on u (<NUM>);
determining (<NUM>), based on different values of uplink control information, UCI, and a first shift index assigned to the transmitter, a shift to apply to the CGS; and
transmitting (<NUM>) the selected CGS, with the determined shift applied, in a short physical uplink control channel, PUCCH, to indicate the UCI.