Patent Description:
Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, <NUM> new radio (NR) communications technology is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, <NUM> communications technology includes enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with strict requirements, especially in terms of latency and reliability; and massive machine type communications for a very large number of connected devices and typically transmitting a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, there exists a need for further improvements in <NUM> communications technology and beyond.

One area of recent improvements has focused on uplink DMRS design, which may impact uplink channel estimation accuracy and eventually determine uplink reliability and throughput. In order to support a large number of user equipments (UEs) in multiple cells, wireless systems have generally relied on a large number of different DMRS sequences. A DMRS sequence may be defined by a cyclic shift (CS) of a base sequence which is dependent on a sequence length and a cell identity. As such CS and the orthogonal covering code (OCC) can be applied to the base sequence to generate multiple orthogonal sequences for a large number of UEs in multi-user multiple input multiple output (MU-MIMO) configuration. However, such an approach may not always be feasible for NOMA due to the large number of DMRS sequences required to support the large number of UEs that are typically in the wireless communication system. <CIT> discloses a UE. The UE receives UE group in-formation indicating a first UE group to which the UE belongs, and transmits uplink (UL) data and a demodulation reference signal (DM-RS), which is for demodulating the UL data, on the basis of the UE group information. The DM-RS is transmitted by means of a first uplink demodulation reference signal (UL DM-RS) resource, which corre-sponds to the first UE group to which the UE belongs, among a plurality of UL DM-RS resources respectively corresponding to one or more UE groups. 3GPP contribution "<NPL>) proposes the sequence binding method which avoids high-peak cross-correlation between different lengths across dif-ferent groups for equal to or more than <NUM>-RB.

As discussed above, uplink DMRS design influences uplink channel estimation accuracy for PUSCH, and thus the reliability of the uplink transmissions and throughput. In order to support a large number of UEs that are typically part of the wireless communication system, current systems require a large number of DMRS sequences in order to minimize traffic collision between multiple UEs transmitting using the same DMRS sequence. However, such an approach is not always feasible.

Specifically, as illustrated in Table <NUM> below that shows the requirement on the number of DMRS sequences for various collision probabilities, in order to achieve a low collision probability, a large DMRS pool is required.

For example, for grant-free UL transmission, a larger number of different DMRS sequences are required to support a large amount of UEs. Typically, in order to manage multiple UEs in a system, the UEs are either preconfigured with exclusive DMRS such that at each transmission time interval (TTI), each active UE may transmit on the same time and frequency resources with preconfigured DMRS sequence, or the UEs may share a pool of DMRS such that at each TTI, an active UE may randomly select one DMRS sequence from the pool. In order to reduce the collision probability, the size of the pool must be sufficiently large to support this configuration.

However, a large DMRS pool with orthogonal sequences is not feasible in a wireless communication system since the DMRS capacity is limited by the assigned time and frequency resources. For example, in current LTE, DMRS occupies one symbol per time slot with a maximum number of <NUM> cyclic shifts results in a total number of <NUM> orthogonal DMRS sequences for a base sequence. Although time domain orthogonal covering code (OCC) can be used to increase the number of orthogonal DMRS sequences, the number of OCC is limited by the number of DMRS symbols, e.g., two for the length-<NUM> OCC in LTE, and probably four for the lengh-<NUM> OCC in NR where up to four DMRS symbols can be transmitted in a slot. Thus, in order to obtain a large number of DMRSs, non-orthogonal DMRS sequences with different base sequences should be considered.

Typically, the non-orthogonal DMRS sequences can provide a larger code space compared to fully orthogonal sequences. However, from reception perspective, the non-orthogonal DMRS may result in channel estimation performance degradation, and thus the overall system capacity performance loss when multiple users transmit the uplink data packet in the same physical resource using the non-orthogonal DMRS sequences with relatively high cross correlation. Thus, random assignment of a non-orthogonal DMRS sequence to UE may not be ideal due to potentially large cross correlation between two sequences (i.e., measure of similarity of any two sequences as a function of the displacement of one relative to the other).

Features of the present disclosure address the above-identified problem by implementing techniques to group the DMRS sequences for a plurality of UEs. In accordance with the first technique, the grouping of the DMRS sequences may be based on the cross correlation of the sequences. For example, sequences with low cross correlation may be selected for each of a plurality of groups and cross correlation between the groups may be larger than a threshold. In another example, the DMRS sequence grouping may be based on either the cubic metric or PAPR (e.g., sequences with similar PAPR may be selected for each group). The cubic metric may be a metric of the actual reduction in power capability, or power de-rating, of a typical power amplifier in a user equipment. The PAPR is the ratio of peak signal power to the average signal power.

Additionally or alternatively, features of the present disclosure may further facilitate power control to enhance DMRS sequence group. For example, same or similar received power may be configured for sequences grouped together such that joint channel estimation may be applied for DMRS sequences with low cross correlation in the same group. Further, different received power can be configured for DMRS sequences that may be grouped separately. Thus, in one instance, a first set of DMRS sequences may be grouped together for a set of first power setting and a second set of DMRS sequences may separately be grouped together for a set of second power settings, where the first set of DMRS sequences is different from the second set of DMRS sequences. In this instance, advanced channel estimation with interference cancellation may be used where the reconstructed received DMRS signals are iteratively cancelled for each UE and subsequently MMSE-IRC based channel estimation algorithm is performed. The successive interference cancellation (SIC) order may be based on the received (Rx) power.

In another example, the base station may provide a plurality of UEs a pool of DMRS sequences and allow each UE to select two base sequences that can be concatenated to construct a long composite sequence. For example, for M base sequences, the concatenation of two base sequences may generate MxM composite sequence, thereby increasing the pool size of DMRS sequences by magnitude of M (i.e., M to MxM). In this manner, the composite sequence may be transmitted by the UE in two consecutive time slots in one subframe (or alternatively two DMRS symbols in a slot). For example, the first base sequence may be transmitted in the first slot and a second base sequence may be transmitted in second slot. As such, different sets of composite sequences can be configured in different cells based on cross correlation between base sequences, and thus reduce interference possibilities between multiple UEs using the same DMRS sequence. Thus, features of the present disclosure provide an advantage over conventional systems in that the traffic collisions are minimized for transmission of DMRS by the UE, which results in improved channel estimation and data throughput between the base station and the UE.

Various aspects are now described in more detail with reference to the <FIG>. Additionally, the term "component" as used herein may be one of the parts that make up a system, may be hardware, firmware, and/or software stored on a computer-readable medium, and may be divided into other components.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations <NUM>, UEs <NUM>, an Evolved Packet Core (EPC) <NUM>, and a <NUM> Core (5GC) <NUM>.

In some aspects, the base station <NUM> may include DMRS sequence management component <NUM> for grouping plurality of DMRS sequences based on cross correlation of the sequences and/or cubic metric and/or PAPR. The DMRS sequence management component <NUM> may exploit uplink power control in grouping different DMRS sequence one or more groups in accordance with various aspects of the present disclosure.

In some examples, one or more UEs <NUM> may include a communication management component <NUM> to perform one or more techniques of the present disclosure. Components and sub-components of the communication management component <NUM> perform one or more techniques of selecting a DMRS sequences from a set of DMRS sequences grouped in a pool. The communication management component <NUM> may transmit the DMRS using the selected DMRS sequence in an uplink to base station <NUM> to perform channel estimation.

The base stations <NUM> configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links <NUM> (e.g., S1 interface). The base stations <NUM> configured for <NUM> NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with 5GC <NUM> through backhaul links <NUM>. The base stations <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or 5GC <NUM>) with each other over backhaul links <NUM> (e.g., X2 interface).

A network that includes both small cell and macro cells may be known as a heterogeneous network. The base stations <NUM> / UEs <NUM> may use spectrum up to FMHz (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

A base station <NUM>, whether a small cell <NUM>' or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or other type of base station.

The 5GC <NUM> may include a Access and Mobility Management Function (AMF) <NUM>, other AMFs <NUM>, a Session Management Function (SMF) <NUM>, and a User Plane Function (UPF) <NUM>. The AMF <NUM> is the control node that processes the signaling between the UEs <NUM> and the 5GC <NUM>.

The base station <NUM> may also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit reception point (TRP), or some other suitable terminology. The base station <NUM> provides an access point to the EPC <NUM> or 5GC <NUM> for a UE <NUM>.

In certain aspects, one or more UEs <NUM> may be configured for CV2X communications between UEs <NUM>. The UEs <NUM> may include various devices related to vehicles and transportation. For example, the UEs <NUM> may include vehicles, devices within vehicles, and transportation infrastructure such as roadside devices, tolling stations, fuel supplies, or any other device that that may communicate with a vehicle. A UE <NUM> may act as either a host device or a client device for CV2X communication. A host UE <NUM> may advertise CV2X services supported by the host UE <NUM>. A client UE <NUM> may also discover CV2X services supported by the host UE <NUM>.

Aspects of the present disclosure address the above-identified problem by providing techniques for a communication management component <NUM> of a base station <NUM> to transmit a "short-page" message (e.g., paging indicators) to one or more UEs <NUM>. The short-page message may be decoded by all UEs <NUM> in the paging cycle and identifies a subset of UEs <NUM> from the full set of UEs <NUM> that are paged by the base station. Upon decoding the short page transmitted by the base station <NUM>, the paging management component <NUM> of the UE <NUM> may respond with a "short-page response" to the base station on a transmit beam that offers best signal quality (e.g., low signal-to-noise ratio). Thus, in this manner, the paging management component <NUM> of the UE <NUM>, in response to receiving a short paging message, may provide feedback to the base station <NUM> such that the base station <NUM> may select a transmit beam for transmission for a subsequent long page message (or other communications). Features of the communication management component <NUM> of the base station <NUM> and the paging management component <NUM> of the UE <NUM> are described in more detail below.

The wireless communication network <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.

<FIG> illustrates a diagram <NUM> of resource management for orthogonal transmission and NOMA in accordance with features of the present disclosure. Specifically, in the CDMA and OFDMA transmission, the one or more UEs are allocated full scope orthogonal resources of frequency, time or code to transmit. In contrast, for NOMA, the same allocation of both frequency and time resource is configured for multiple users, for example, two UEs can transmit on the same time/frequency resources using the non-orthogonal code and different transmission power settings. Thus, as illustrated, in <FIG>, NOMA with short codes allows for six UEs on four resources with length-<NUM> short codes utilization.

<FIG> illustrates an example of cross correlation <NUM> between DMRS sequences that are utilized by the base station to group the DMRS sequences in accordance with features of the present disclosure. Specifically, as noted above, random assignment of a non-orthogonal DMRS sequence to UE may be problematic due to potentially large cross correlation between two DMRS sequences. As such, it may be difficult for the base station to estimate the channels for the co-scheduled UEs where the DMRS sequences have large cross correlation. Table <NUM> illustrates the cross correlation for various DMRS sequence lengths.

As such, in accordance with the first technique of the present disclosure, the base station may group a set of DMRS sequences from the plurality of DMRS sequences based on cross correlation of sequences. For example, sequences with low cross correlation may be selected for each group and cross correlation between the groups may be larger than a threshold. Additionally or alternatively, the base station may group the plurality of DMRS sequences based on cubic metric or PAPR. For example, sequences with similar PAPR may be selected for each control.

In some examples, as illustrated in <FIG>, a base station may also utilize power control to facilitate the sequence grouping. For example, the same or similar received power may be allocated for sequences in the same group. This may facilitate joint channel estimation to be applied for sequences in the same group due to low cross correlation property. To that end, different received power for sequences may be allocated to different groups. As such, channel estimation with advanced interference cancellation may be used and the SIC order may be based on the received power.

In some implementations, the base station may broadcast the DMRS sequence grouping in system information block (SIB). For example, the base station may group a subset of sequences and the associated RSRP threshold (or repetition level for the associated UL data transmission) to the one or more UEs. For example, a first set of DMRS sequences {s1, s2, and s3) may be allocated for RSRP that is less than -100dB and a second set of DMRS sequences {s4, s5, and s6} for RSRP greater than 100dB. Thus, each UE in the cell may choose the DMRS group and sequence based on its RSRP (or the used repetition level for the associated data transmission).

In some examples, a base station may signal a group number and a sequence index determined from the RSRP measurement report or based on the configured repetition level used for data transmission. In some examples, the base station may also configure the transmit power for the assigned DMRS sequences.

<FIG> illustrates an example composite sequence <NUM> that is generated by concatenating a plurality of base sequences in accordance with features of the present disclosure. In some examples, in order to ensure low probability of collision between multiple UEs selecting the same DMRS sequence that may impact channel estimation, the DMRS sequences are selected by concatenating a plurality of base sequences (at least two, but may also include additional sequences combined together) to generate a composite sequence. For example, two base sequences may be concatenated to construct a single long composite sequence. By implementing this technique, the concatenation of two base sequences generates M x M composite sequence that would otherwise would only be limited to M (M being an integer). The greater number of available sequences may reduce the collision. The feature of the present disclosure provides an advantage over the approach by increasing the number of base sequences which may result in a significant increase of the receiver complexity for sequence detection.

In some examples, the composite sequences are transmitted in multiple slots (e.g., two slots). For example, the first DMRS sequence is transmitted in the first slot, and the second DMRS sequence is transmitted in a second slot. As illustrated, different sets of composite sequences may be configured in different cells based on cross correlation between base sequences. Thus, once the base station has provided a pool of DMRS sequences for selection based on the grouping, the UE may randomly choose two base sequences, for example, to be transmitted in two slots (or alternatively two DMRS symbols in a slot). Such full collision may occur when the number of the selected base sequences are less than the number of UEs in both slots. In this instance, the probability of a full collision where at least two UEs select the same base sequence for both slots (i.e., first slot and second slot) would be lower or reduced.

A partial collision may also occur where the at least two UEs select the same DMRS sequence in one slot, but not the other. This is the case when the number of selected base sequences in one slot is equal to the number of UEs transmitted in that slot. Conversely, the likelihood of having no collisions is high when no duplicate UEs in the same cell select the same sequence for either slot. However, with implementation of these techniques, only full collision in both slots may lead to transmission failure. Indeed, even in case of partial collision where one of two slots has the same DMRS sequence as another UE, the base station may still be able to estimate channel from DMRS in the collision-free slot for the UEs. As such, the probability of the DMRS collision by implementation of the composite sequence in at least two slots is reduced by the power of two (P<NUM>), where P is the collision probability for the non-composite sequence (e.g., using the same base sequences in both slots for all the UEs).

Now turning to <FIG> that illustrate an example of the system identifying the linkage between two base sequences that are received by the base station in two separate slots (or alternatively two DMRS symbols in a slot) in accordance with aspects of the present disclosure. Typically, when grant-free UL transmission is configured, there is one-to-one mapping between the DMRS sequence and the PUSCH parameters such as the RNTI and/or MA signature for NOMA (e.g., codebook, spreading code sequence, interleaver pattern etc). Since for grant-free transmission, when a UE performs random resource selection for uplink transmission, the base station does not have prior information about which UE is transmitted on the resource. In this case, the predefined DMRS to the PUSCH mapping can facilitate the receiver procedure of the base station <NUM>. Upon receiving a composite DMRS sequence, the base station may be required to determine the linkage between the received two DMRS base sequences in order to identify the RNTI and MA signature used for PUSCH transmission. However, implementing this technique for composite DMRS sequence may be more challenging because it may be difficult to detect the composite sequence index from DMRS base sequences received in two slots when there are more than one DMRS sequences are received in each of the slots.

As illustrated in <FIG>, one solution may be to conduct an exhaustive search by hypothesizing all the combinations and CRC confirming data decoding results. For example, as illustrated, the base station may receive three DMRS sequences from three UEs during the first slot (slot <NUM>), and another three DMRS sequences during the second slot (slot <NUM>). One technique may involve attempting to identify all possible combinations (<NUM> possible combinations in the illustrated example). However, such an approach may be resource intensive as the number of UEs in the cell increases.

<FIG> illustrates a cyclic shift hopping pattern <NUM> in accordance with features of the present disclosure in order to more effectively identify the received DMRS base sequences with the PUSCH. In such a solution, the cyclic shift hopping for one sequence is based on the other base sequence index in the composite sequence. For example, the DMRS sequences in two slots of one subframe may be given by ru<NUM>α<NUM> and ru<NUM>α<NUM> where u<NUM> and u2 are the index of base sequence, α<NUM> and α<NUM> are the cyclic shift in subframe n may be defined by α<NUM>=2πnCS, <NUM>/N and α2=2πnCS, <NUM>/N: <MAT> <MAT>.

In the above formulas that facilitate sequence specific cyclic shift hopping pattern over subframes, N may be the sequence length, and nλ, <NUM> and nλ, <NUM> are initial cyclic shift value provided by the higher layer signaling of the system. Thus, the linkage between the two base sequences may be determined from the associated cyclic shift hopping values, thereby allowing the base station to identify the composite sequence index for each UE in order to identify the MA signature used for data transmission.

<FIG> is a flowchart of an example method <NUM> that illustrates the cyclic shift hopping pattern employed by the base station in accordance with aspects of the present disclosure. At blocks <NUM>, the method may include detecting a first set of DMRS sequences in first slot (or alternatively first DMRS symbol in a slot) and a second set of DMRS sequences in second slot (or alternatively second DMRS symbol in a slot).

At block <NUM>, the method may include the base station determining the cyclic hopping values for sequences in first set and the second set. At block <NUM>, the method may include determining the linkage between the sequences in two sets based on the cyclic hopping values. At block <NUM>, the method may include determining the PUSCH parameters including RNTI and MA signature based on the linkage. At block <NUM>, the method may include determining the collision-free slot and calculating channel estimation in collision-free slots. At block <NUM>, the method may include performing multiple user detection and PUSCH decoding.

<FIG> describes hardware components and subcomponents of a device that may be a base station <NUM> for implementing one or more methods (e.g., method <NUM>) described herein in accordance with various aspects of the present disclosure. For example, one example of an implementation of the transmitting device may include a variety of components, some of which have already been described above, but including components such as one or more processors <NUM> and memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with the DMRS sequence management component <NUM> to group a plurality of DMRS sequences for channel estimation based on cross correlation between the multiple sequences and cubic metric or PAPR. In some examples, the DMRS sequence management component <NUM> may include a sequence grouping component <NUM> to facilitate such grouping. The DMRS sequence management component <NUM> may include a composite sequence component <NUM> for associating the plurality of base sequences received over a plurality of time slots (or alternatively a plurality of DMRS symbols in a slot) to the transmitting UE based on cyclic shift hopping patter over subframes. Thus, the DMRS sequence management component <NUM> may perform functions described herein related to including one or more methods of the present disclosure.

The one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM>, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. In an aspect, the one or more processors <NUM> can include a modem <NUM> that uses one or more modem processors. The various functions related to DMRS sequence management component <NUM> may be included in modem <NUM> and/or processors <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or modem <NUM> associated with DMRS sequence management component <NUM> may be performed by transceiver <NUM>.

Also, memory <NUM> may be configured to store data used herein and/or local versions of applications or DMRS sequence management component <NUM> and/or one or more of its subcomponents being executed by at least one processor <NUM>. Memory <NUM> can include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining DMRS sequence management component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when base station <NUM> is operating at least one processor <NUM> to execute DMRS sequence management component <NUM> and/or one or more of its subcomponents.

Receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). In an aspect, receiver <NUM> may receive signals transmitted by at least one UE <NUM>. Additionally, receiver <NUM> may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. Transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium).

Moreover, in an aspect, transmitting device may include RF front end <NUM>, which may operate in communication with one or more antennas <NUM> and transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station <NUM> or wireless transmissions transmitted by UE <NUM>. For purposes of this disclose, the term "antenna" may refer to include one or more antennas, antenna elements and/or antenna arrays.

In an aspect, transceiver may be tuned to operate at specified frequencies such that transmitting device can communicate with, for example, one or more base stations <NUM> or one or more cells associated with one or more base stations <NUM>. In an aspect, for example, modem <NUM> can configure transceiver <NUM> to operate at a specified frequency and power level based on the configuration of the transmitting device and the communication protocol used by modem <NUM>.

In an aspect, modem <NUM> can control one or more components of transmitting device (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration.

<FIG> is a flowchart of an example method <NUM> for grouping DMRS sequences for wireless communications system in accordance with aspects of the present disclosure. The method <NUM> may be performed using an apparatus (e.g., the base station <NUM>). Although the method <NUM> is described below with respect to the elements of the base station <NUM>, other components may be used to implement one or more of the steps described herein.

At block <NUM>, the method may include determining, at the base station, a cross correlation for a plurality of DMRS sequence for UL transmission without a grant. The method may also include determining one or more of a cubic metric or PAPR and grouping the plurality of DMRS sequences based on the one or more of the cubic metric or the PAPR. Aspects of block <NUM> may be performed by the DMRS sequence management component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include grouping the plurality of DMRS sequences based on the cross correlation for the plurality of DMRS sequences. The grouping may include selecting a first set of DMRs sequences from the plurality of DMRS sequences with low cross correlation for a first group. Additionally, the grouping may include selecting a second set of DMRS sequences with high cross correlation to the first set of DMRS sequences for a second group. Aspects of block <NUM> may be performed by the sequence grouping component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include transmitting a DMRS sequence grouping to the UE. The transmitting may include broadcasting the DMRS sequence grouping in system information blocks (SIB), wherein the DMRS sequence grouping identifies a subset of DMRS sequences grouping and associated reference signal received power (RSRP) threshold for each group in the DMRS sequence grouping. The transmitting may also include broadcasting the DMRS sequence grouping in SIB, wherein the DMRS sequence grouping identifies a subset of DMRS sequences grouping and the repetition level threshold associated with UL data transmission for each group in the DMRS sequence grouping. In some examples, transmitting may also include transmitting a group number and a sequence index associated with the DMRS sequence grouping, and configuring a transmission power of the UE for the assigned DMRS sequence. Aspects of block <NUM> may be performed by the sequence grouping component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include receiving, at the base station, a first DMRS sequence from a UE during a first slot. Aspects of block <NUM> may be performed by the DMRS sequence management component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include receiving, at the base station, a second DMRS sequence from the UE during a second slot. Aspects of block <NUM> may be performed by the DMRS sequence management component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include determining a cyclic shift hopping on the first DMRS sequence during the first slot in order to identify a base sequence index of the second DMRS sequence in the second slot. Aspects of block <NUM> may be performed by the composite sequence component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include determining a linkage between the first DMRS sequence and the second DMRS sequence based on the cyclic shift hopping. Aspects of block <NUM> may be performed by DMRS sequence management component <NUM> described with reference to <FIG>.

At block <NUM>, the method may include determining a PUSCH parameter including RNTI and MA signature based on the linkage. Aspects of block <NUM> may be performed by DMRS sequence management component <NUM> described with reference to <FIG>.

<FIG> describes hardware components and subcomponents of a device that may be a UE <NUM> for implementing one or more methods (e.g., method <NUM>) described herein in accordance with various aspects of the present disclosure. For example, one example of an implementation of the transmitting device may include a variety of components, some of which have already been described above, but including components such as one or more processors <NUM> and memory <NUM> and transceiver <NUM> in communication via one or more buses <NUM>, which may operate in conjunction with the communication management component <NUM> to select DMRS sequence for uplink channel estimation from a pool of DMRS sequences that are grouped based on cross correlation of the sequences and PMPR. In some examples, the communication management component <NUM> may include a sequence concatenation component <NUM> selecting a plurality of base sequences (e.g., at least two sequences) to form a set of DMRS sequences that are grouped together. Thus, the communication management component <NUM> may perform functions described herein related to including one or more methods of the present disclosure.

The one or more processors <NUM>, modem <NUM>, memory <NUM>, transceiver <NUM>, RF front end <NUM> and one or more antennas <NUM>, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. In an aspect, the one or more processors <NUM> can include a modem <NUM> that uses one or more modem processors. As noted above, for purposes of this disclose, the term "antenna" may refer to include one or more antennas, antenna elements and/or antenna arrays. The various functions related to communication management component <NUM> may be included in modem <NUM> and/or processors <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver <NUM>. In other aspects, some of the features of the one or more processors <NUM> and/or modem <NUM> associated with communication management component <NUM> may be performed by transceiver <NUM>.

Also, memory <NUM> may be configured to store data used herein and/or local versions of applications or communication management component <NUM> and/or one or more of its subcomponents being executed by at least one processor <NUM>. Memory <NUM> can include any type of computer-readable medium usable by a computer or at least one processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining communication management component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when UE <NUM> is operating at least one processor <NUM> to execute communication management component <NUM> and/or one or more of its subcomponents.

Moreover, in an aspect, transmitting device may include RF front end <NUM>, which may operate in communication with one or more antennas <NUM> and transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station <NUM> or wireless transmissions transmitted by UE <NUM>.

In an aspect, modem <NUM> can control one or more components of transmitting device (e.g., RF front end <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In another aspect, the modem configuration can be based on UE configuration information associated with transmitting device as provided by the network during cell selection and/or cell reselection.

<FIG> is a flowchart of an example method <NUM> implemented by a UE for wireless communications system in accordance with aspects of the present disclosure. The method <NUM> may be performed using an apparatus (e.g., the UE <NUM>). Although the method <NUM> is described below with respect to the elements of the UE <NUM>, other components may be used to implement one or more of the steps described herein.

At block <NUM>, the method includes receiving a DMRS sequence grouping from the base station. In some examples, the DMRS sequence grouping is received from the base station in SIB. The DMRS sequence grouping may identify a subset of DMRS sequences grouping and associated RSRP threshold (or repetition level for the associated data transmission) for each group in the DMRS sequence grouping. The DMRS sequence grouping may also include a group number and a sequence index associated with the DMRS sequence grouping. Aspects of block <NUM> may be performed by the transceiver <NUM> described with reference to <FIG>.

At block <NUM>, the method includes selecting a DMRS sequence for transmission of DMRS for uplink transmission without grant based on the DMRS sequence grouping. Selecting the DMRS sequence for transmission of DMRS based on the DMRS sequence grouping, may comprise selecting a group number and a sequence based on the comparison of the RSRP measurement to the associated RSRP threshold for each group in the DMRS sequence grouping. In other examples, the selecting may include selecting a group number and a sequence based on the repetition level used for the associated UL data transmission. Further, selecting includes concatenating a plurality of base sequences to construct a composite DMRS sequence. In the instance of composite DMRS sequence, the UE <NUM> transmits a first base sequence during a first slot and a second base sequence during a second slot. Aspects of block <NUM> may be performed by the communication management component <NUM> described with reference to <FIG>.

At block <NUM>, the method may optionally include configuring a transmission power of the UE for the selected DMRS sequence based on the DMRS sequence grouping. Aspects of block <NUM> may be performed by the power control component <NUM> described with reference to <FIG>.

At block <NUM>, the method includes transmitting an uplink data along with the DMRS for uplink transmission using contention-based protocol (e.g., without L1 grant). In some examples, the DMRS is transmitted based on the selected DMRS sequence. The method also includes transmitting the composite DMRS sequence in the two consecutive slots of a plurality subframes (or alternatively two DMRS symbols in a slot) , and performing a cyclic shift hopping on the first DMRS sequence based on the base sequence index of the second DMRS sequence. The method further includes performing a cyclic shift hopping on the second DMRS sequence based on the base sequence index of the first DMRS sequence. Aspects of block <NUM> may be performed by the transceiver <NUM> described with reference to <FIG>.

Claim 1:
A method for wireless communications implemented by a user equipment, UE (<NUM>), comprising:
receiving (<NUM>) a demodulation reference signal, DMRS, sequence grouping from a base station (<NUM>), the DMRS sequence grouping identifying one or more groups of DMRS sequences, each group of DMRS sequences corresponding to a set of DMRS sequences from a plurality of DMRS sequences;
selecting (<NUM>) a DMRS sequence for transmission of DMRS based on the DMRS sequence grouping; and
transmitting (<NUM>) uplink, UL, data along with the DMRS for UL transmission using contention-based protocol, wherein the DMRS is transmitted based on the selected DMRS sequence;
wherein selecting the DMRS sequence for transmission of DMRS based on the DMRS sequence grouping comprises concatenating a plurality of base sequences to construct a composite DMRS sequence, wherein the plurality of base sequences includes at least two sequences selected from the one or more groups of DMRS sequences,
the method further comprising:
transmitting the composite DMRS sequence in one or more of slots of a plurality subframes, wherein a first DMRS sequence is transmitted in a first slot and a second DMRS sequence is transmitted in a second slot, and wherein the first DMRS sequence has a first base sequence index and the second DMRS sequence has a second base sequence index;
performing a cyclic shift hopping on the first DMRS sequence based on the second base sequence index; and
performing a cyclic shift hopping on the second DMRS sequence based on the first base sequence index.