DYNAMIC ADDITIONAL DEMODULATION REFERENCE SIGNAL CONFIGURATION

A system can configure a first number of demodulation reference signal (DMRS) positions as part of a connection setup with a user equipment that is configured to facilitate broadband cellular communications. The system can, after attaching the user equipment, send, to the user equipment, a first medium access control control element (MAC-CE) message indicative of modifying the first number of DMRS positions to a second number of DMRS positions for a primary cell. The system can, in response to determining that a secondary cell is activated with respect to the user equipment, send, to the user equipment, a second MAC-CE message indicative of modifying the first number of DMRS positions to the second number of demodulation reference signal positions for the secondary cell. The system can communicate with the user equipment according to the second number of DMRS positions.

BACKGROUND

In cellular broadband communications, a user equipment and a core network can communicate to configure a protocol to use in making further communications.

SUMMARY

An example system can operate as follows. The system can configure a first number of demodulation reference signal positions in radio resource control information as part of a connection setup with a user equipment that is configured to facilitate first broadband cellular communications. The system can, after attaching the user equipment, send, to the user equipment, a first medium access control control element message indicative of modifying the first number of demodulation reference signal positions to a second number of demodulation reference signal positions for a primary cell. The system can, in response to determining that a secondary cell is activated with respect to the user equipment, send, to the user equipment, a second medium access control control element message indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for the secondary cell. The system can communicate, via second broadband cellular communications, with the user equipment according to the second number of demodulation reference signal positions, wherein a throughput of the second broadband cellular communications is determined as a function of a size of a transport block set based on the second number of demodulation reference signal positions.

An example method can comprise, after attaching a user equipment that is configured to facilitate first broadband cellular communications, sending, by a system comprising a processor, and to the user equipment, a first medium access control control element message indicative of a first number of demodulation reference signal positions that was established as part of a connection setup being modified to a second number of demodulation reference signal positions for a primary cell. The method can further comprise, in response to determining that a secondary cell is activated with respect to the user equipment, sending, by the system and to the user equipment, a second medium access control control element message indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for the secondary cell. The method can further comprise communicating, by the system via broadband cellular communications, with the user equipment according to the second number of demodulation reference signal positions.

An example non-transitory computer-readable medium can comprise instructions that, in response to execution, cause a system comprising a processor to perform operations. These operations can comprise, after attaching a user equipment that is configured to facilitate first broadband cellular communications, sending, to the user equipment, a first medium access control control element message indicative of a modified number of demodulation reference signal positions that was established as part of a connection setup for a primary cell. These operations can further comprise, in response to determining that a secondary cell is activated with respect to the user equipment, sending, to the user equipment, a second medium access control control element message indicative of the modified number of demodulation reference signal positions for the secondary cell. These operations can further comprise conducting second broadband cellular communications with the user equipment according to the modified number of demodulation reference signal positions.

DETAILED DESCRIPTION

The examples described herein can generally relate to actions taken by a base station in communicating with a user equipment to dynamically configure additional demodulation reference signals. This dynamic configuration of additional demodulation reference signals can be established via a Medium Access Control Control Element (MAC-CE) message. In some examples, a MAC-CE message is sent at a MAC layer of cellular communications. Communications conducted at a MAC layer can be faster as compared to, for example, Radio Resource Control (RRC) layer communications.

In some examples of cellular communications, RRC and Non-access stratum (NAS) layer messages can be used to exchange signaling between a base station and user equipment. A MAC layer communication path can be another such path. In MAC layer communications, unique MAC structures can be defined that carry certain control information. In some examples, a unique MAC structure can be implemented to carry control information, and this structure can be referred to as a MAC-CE.

A MAC-CE can work between a base station (MAC) and a user equipment (MAC) for fast signaling communication exchange without involving higher communication layers.

It can be appreciated that corresponding actions can be taken by user equipment to also dynamically configure additional demodulation reference signals.

In cellular communications, there can be a master cell group (MCG) to which a user equipment (UE) initially registers. A cell that is used to initiate initial access can be referred to as a primary cell (Pcell). A Pcell can be combined with one or more secondary cells (Scells) under a MCG using carrier aggregation techniques, which can generally involve combining multiple carriers to increase bandwidth available to UEs.

The examples herein generally relate to 5G cellular communications networks, where Pcells and Scells are used. It can be appreciated that the present techniques can be applied to other types of cellular communications networks for dynamically configuring additional demodulation reference signals (DMRSes).

A DMRS can be utilized by a 5G new radio (NR) receiver to produce channel estimates for demodulation of an associated physical channel. A design and mapping of each DMRS can be specific to each 5G physical channel (e.g., physical broadcast channel (PBCH), physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), physical uplink control channel (PUSCH), and physical uplink shared channel (PUCCH)). DMRS can be UE specific, and be transmitted on demand. In some examples, a DMRS does not extend outside of a scheduled physical resource of a channel it supports. DMRS can support massive multi-user multiple-input and multiple-output (MIMO). DMRS can be beamformed and, in some examples, support up to 13 orthogonal symbols. A DMRS sequence for a cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) version can be quadrature phase shift keying (QPSK) based on Gold Sequences.

With respect to PDSCH, DMRS can comprise front-loaded DMRS symbols (e.g., either 1 or 2) that are located as follows:1. Slot based (DMRS mapping type-A); This can be a fixed orthogonal frequency division multiplexing (OFDM) symbol regardless of PDSCH assignment and that is configurable between lo={2,3}. Here, “Lo” means dmrs-typeA-position, which can be present at symbol2 or symbol3.2. Non-slot based (DMRS mapping type-B); This can be a first OFDM symbol assigned for PDSCH—e.g., mini slots.

In some examples, additional DMRS symbols can be configured in scenarios such as high-speed mobility (e.g., handover); when downlink (DL)/uplink (UL) block error ratio (BLER) is high, and UE-reported channel condition is poor; and when a UE is located on a cell edge, and, because of that, the UE is not able to decode or send DL and UL packets.

With regard to PUSCH DMRS, in an uplink, two waveform types can be supported (e.g., CP-OFDM, and discrete Fourier transform-spread orthogonal frequency division multiplexing (DFT-S-OFDM)). For instance, a gold sequence can be used in CP-OFDM, and a Zadoff-Chu sequence can be used in DFT-S-OFDM. Front loaded DMRS symbols (e.g., either 1 or 2) can be located at a first OFDM symbol that is assigned for PUSCH.

The present techniques can be implemented to solve the following problems that can relate to Scells with respect to downlink carrier aggregation.

One problem that can be solved by implementing the present techniques can be when a 5G base station (sometimes referred to as gNodeB or gNB; or more generally a base station) includes an dmrs-AdditionalPosition information element (IE) using DMRS-DownlinkConfig and DMRS-UplinkConfig for downlink and uplink, respectively, during a UE's attach or another UE-specific procedure, then that configuration can stay with the UE during the lifetime of the scenario unless it is modified by a radio resource control (RRC) modification procedure.

A dmrs-AdditionalPosition IE for DL and UL is indicated inFIGS.1and2, respectively. That is,FIG.1illustrates an example DMRS downlink configuration information element100that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure. In example DMRS downlink configuration information element100, there is dmrs-AdditionalPosition102.

AndFIG.2illustrates an example DMRS uplink configuration information element200that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure. In the example DMRS uplink configuration information element200, there is dmrs-AdditionalPosition202.

Once this configuration is received by the UE, then the gNB and the UE can consider that configuration while determining a transport block (TB; which can generally determine data throughput of the UE). A TB can vary based on a number of additional DMRS positions that are configured.

Where a UE has one or more secondary cells that are activated, and the UE is configured with additional DMRS configuration for uplink and/or downlink, then this configuration can be applicable to all secondary cells where the UE is configured for Scells through RRC messaging.

Data throughput (TP) can be inversely proportional to a number of configured additional DMRS positions—that is, where more additional DMRS symbols are configured then there can be less data throughput.

FIGS.3A and3Billustrate an example additional DMRS configuration300A and300B that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure. Example additional DMRS configuration300A and300B (as well as example additional DMRS configuration400A and400B ofFIGS.4A and4B; example additional DMRS configuration500A and400B ofFIGS.5A and5B; and example additional DMRS configuration600A and600B ofFIGS.6A and6B) can have the following settings:pdsch.NumLayers=4;pdsch.MappingType=‘A’;pdsch.SymbolAllocation=[0 15]; % [startSymbol Length]dmrs.DMRSconfigurationType=1;dmrs.DMRSLength=1;dmrs.DMRSTypeAPosition=2;dmrs.NumCDMGroupsWithoutData=2;dmrs.NIDNSCID=10;dmrs.NSCID=0;

Additionally, example additional DMRS configuration300A and300B has “dmrs.DMRSAdditionalPosition=0;” which indicates that there are no additional DMRS positions configured. This configuration is illustrated in additional DMRS configuration300A and300B, which comprises port1000302A (with subcarriers304A and OFDM symbols306A); port1001302B (with subcarriers304B and OFDM symbols306B); port1002302C (with subcarriers304C and OFDM symbols306C); and port1003302D (with subcarriers304D and OFDM symbols306D).

Example additional DMRS configuration300A and300B also comprises dynamic additional DMRS configuration component310(which can comprise a computer component that implements the present techniques) and key308.FIGS.3A and3Brelate to a 4-port antenna configuration, and dynamic additional DMRS configuration component310can comprise a 4-port dynamic additional DMRS configuration component.

FIGS.4A and4Billustrate another example additional DMRS configuration400A and400B that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure.

Example additional DMRS configuration400A and400B has “dmrs.DMRSAdditionalPosition=1;” which indicates that there is one additional DMRS position configured. This configuration is illustrated in additional DMRS configuration400A and400B, which comprises port1000402A (with subcarriers404A and OFDM symbols406A); port1001402B (with subcarriers404B and OFDM symbols406B); port1002402C (with subcarriers404C and OFDM symbols406C); and port1003402D (with subcarriers404D and OFDM symbols406D).

Example additional DMRS configuration400A and400B also comprises dynamic additional DMRS configuration component410(which can comprise a computer component that implements the present techniques) and key408.

FIGS.5A and5Billustrate another example additional DMRS configuration500A and500B that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure.

Example additional DMRS configuration500A and500B has “dmrs.DMRSAdditionalPosition=2;” which indicates that there are two additional DMRS positions configured. This configuration is illustrated in additional DMRS configuration500A and500B, which comprises port1000502A (with subcarriers504A and OFDM symbols506A); port1001502B (with subcarriers504B and OFDM symbols506B); port1002502C (with subcarriers504C and OFDM symbols506C); and port1003502D (with subcarriers504D and OFDM symbols506D).

Example additional DMRS configuration500A and500B also comprises dynamic additional DMRS configuration component510(which can comprise a computer component that implements the present techniques) and key508.

FIGS.6A and6Billustrate another example additional DMRS configuration600A and600B that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure.

Example additional DMRS configuration600A and600B has “dmrs.DMRSAdditionalPosition=3;” which indicates that there are three additional DMRS positions configured. This configuration is illustrated in additional DMRS configuration600A and600B, which comprises port1000602A (with subcarriers604A and OFDM symbols606A); port1001602B (with subcarriers604B and OFDM symbols606B); port1002602C (with subcarriers604C and OFDM symbols606C); and port1003602D (with subcarriers604D and OFDM symbols606D).

Example additional DMRS configuration600A and600B also comprises dynamic additional DMRS configuration component610(which can comprise a computer component that implements the present techniques) and key608.

In the example ofFIGS.3A and3B, there is no additional DMRS configured. In the example ofFIGS.4A and4B, there is one additional DMRS symbol configured. In the example ofFIGS.5A and5B, there are two additional DMRS symbols configured. In the example ofFIGS.6A and6B, there are three additional DMRS symbols configured. So, in these examples, data throughput inFIGS.3A and3Bcan be greater than inFIGS.4A and4B, which can be greater than inFIGS.5A and5B, which can be greater than inFIGS.6A and6B.

As part of dynamically configuring additional DMRS positions, a component (e.g., dynamic additional DMRS configuration component310ofFIGS.3A and3B) can dynamically switch between the configurations ofFIGS.3Aand AB,4A and4B,5A and5B, and6A and6B

One problem with additional DMRS configuration can be physical resource block (PRB) wastage because of an unnecessarily-configured higher additional DMRS position. Implementing the present techniques to dynamically change the additional DMRS position for each primary carrier component (Pcc) and secondary carrier component (Scc) can be implemented to solve this problem.

Take an example where, during UE attach, a gNB configured an additional DMRS configuration in pos3 (indicating 3 additional DMRS symbols) for primary and secondary cells. Where radio/channel condition is good, where the UE is reporting a channel quality indicator (CQI), and UL and DL data BLER % are under 1% (indicating that a PDSCH and PUSCH packet decoding success rate is high), then having 3 symbols for additional DMRS can negatively impact data throughput.

Some prior approaches do not allow changing this configuration dynamically, and because of that, the gNB can be unnecessarily wasting a physical resource block.

Another problem with additional DMRS configuration can relate to frequent UE release, a UE performing a RRC reestablishment procedure, or a secondary cell failure procedure, because channel condition is poor. Implementing the present techniques to dynamically change the additional DMRS position can be implemented to solve this problem.

Take an example where, during UE attach, the gNB has not configured an additional DMRS configuration in DL and or UL. Where radio/channel condition is poor for the primary cell and/or secondary cell(s), where the UE is reporting CQI for primary and/or secondary cell(s) that is bad, and UL and DL BLER % is high for both cells (e.g., >20%, which can indicate that a success rate of decoding PDSCH packets is poor), it can be that the UE or gNB can perform a UE release, secondary cell failure procedure, and/or RRC reestablishment procedure. This procedure can take a long time to restore the connection. This problem can be avoided by dynamically configuring additional DMRS positions for primary and secondary cells based on channel quality to sustain the connection. In some prior approaches, this configuration cannot be dynamically altered.

Another problem with additional DMRS configuration can relate to a high-speed mobility (handover) scenario. In a high-speed handover scenario, channel/radio condition can be kept on frequently with respect to primary and/or secondary cells, to sustain and maintain good quality for a call. Additional DMRS symbols can be adapted dynamically based on reported CQI and BLER for all activated carriers, to achieve good throughput, while also not compromising by wasting physical resources.

Another problem with additional DMRS configuration can relate to a scenario where a UE is located at a cell edge. It can be that, when a UE is located at a cell edge, the UE's channel quality is subpar, and BLER % can be high for primary and/or secondary cells. To improve this condition, a gNB can quickly adapt an additional DMRS configuration. It can be that adapting a DMRS configuration based on link adaptation is not supported by prior approaches.

The present techniques for dynamic additional DMRS configuration can be implemented as follows.

One approach can be to use a new MAC-CE (e.g., “activation/deactivation of additional DMRS information”), which can be a MAC-CE for downlink and uplink, where a highest ServCellIndex of a serving cell with configured downlink/uplink is less than 8 (or some threshold number). There can be downlink secondary cells activation with downlink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE for primary and/or secondary cell(s).

Uplink secondary cell activation with uplink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE can also be implemented.

Another approach can be to use a new MAC-CE (e.g., “activation/deactivation of additional DMRS information”), which can be a MAC-CE for downlink and uplink, where a highest ServCellIndex of a serving cell with configured downlink/uplink is 8 or more (or some threshold number). There can be downlink secondary cells activation with downlink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE for primary and/or secondary cell(s).

Uplink secondary cell activation with uplink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE can also be implemented.

Another approach can be to use a new IE in UE capability for downlink and uplink. A new IE, dynamicAdditionalDMRSSupport, can be added for downlink in FeatureSetDownlink. If UE supports this IE, it can mean that the UE will support dynamic additional DMRS configuration changes in a downlink direction.

Additionally, a new IE, dynamicAdditionalDMRSSupport, can be added for downlink in FeatureSetUplink. If UE supports this IE, it can mean that the UE will support dynamic additional DMRS configuration changes in an uplink direction.

Another approach can be to use a new IE, dynamicAdditionalDMRSSupport, in PDSCH-Config for downlink and PUSCH-Config for uplink.

Another approach can be to configure UE to be capable of handling a MAC-CE for downlink and uplink with secondary cell activated. That is, UE can be configured to handle one or both of activation/deactivation of additional DMRS information MAC-CE with a highest ServCellIndex of the serving cell with configured downlink/uplink less than 8 (or a threshold value), and activation/deactivation of additional DMRS information MAC-CE with a highest ServCellIndex of the serving cell with configured downlink/uplink greater than or equal to 8 (or a threshold value).

In this approach, a gNB can send one of these MAC-CEs for downlink with D=1 and with a proper value of index determined based on an algorithm. This field can be decoded by UE, which can apply the new configuration in further processing.

A gNB can send one of these MAC-CEs for uplink with U=0 and with a proper value of index determined based on an algorithm. This field can be decoded by UE, which can apply the new configuration in further processing.

Downlink secondary cells activation with downlink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE for primary and/or secondary cells can be applied. Additionally, uplink secondary cells activation with uplink data flow with logic for triggering dynamic additional DMRS configuration using MAC-CE can be applied.

FIG.7illustrates an example system architecture700that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure. System architecture comprises gNB702, UE704, CQI processing706, inner loop link adaptation (ILLA)708, and gNB outer loop link adaptation (OLLA)710(which, in some examples, can more generally be a base station outer loop link adaptation).

In some examples, gNB702can determine additional DMRS information dynamically, as follows. As depicted inFIG.7, where UE704is reporting channel quality using CQI, and hybrid automatic repeat request (HARQ) feedback (e.g., acknowledgment (ACK), negative acknowledgment (NACK), and discontinuous transmission (DTX)) for data transmission for primary and secondary cells, then, OLLA710can handle the HARQ feedback, and CQI processing706(for all activated cells) can handle CQI reported by UE704.

Based on these two inputs, ILLA708can determine a modulation coding scheme (MCS) and additional DMRS position to be applied to UL and DL data transmission for primary and secondary cells where Scells are already activated.

ILLA708can determine the MCS by considering the CQI reported by UE704, and HARQ feedback. In some examples, the higher the MCS, the better the channel/radio quality, meaning a smaller number of additional DMRS positions configured to UE704using the present techniques.

Where ILLA708determines to use a lower MCS, meaning the channel quality reported by UE704is not good and BLER is high, this can mean that ILLA708determines to increase the additional DMRS position in a DL/UL MAC-CE message to decrease the BLER %.

The following can be communicated as part of conveying capability of a UE. A FeatureSetCombination information element can be as follows:

An IE. FeatureSetDownlink, can indicate a set of features that a UE supports on carriers corresponding to one band entry in a band combination. A FeatureSetDownlink IE can be as follows:

In a FeatureSetDownlink IE, a UE can set a dynamicAdditionalDMRSSupport field to support where the UE is capable of supporting downlink additional DMRS features.

An IE, FeatureSetUplink, can indicate a set of features that a UE supports on carriers corresponding to one band entry in a band combination. A FeatureSetUplink IE can be as follows:

In a FeatureSetUplink IE, a UE can set a dynamicAdditionalDMRSSupport field to support where the UE is capable of supporting uplink additional DMRS features.

A PDSCH-Config IE that is used to configure a UE's specific PDSCH parameters can be as follows:

An IE, PUSCH-Config, that can be used to configure UE specific PUSCH parameters applicable to a particular band width part (BWP) can be as follows:

FIGS.8A and8Billustrate example MAC-CE message formats800for activation/deactivation of additional DRMS information, and that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure.

In MAC-CE message810, bit812indicates a bit number for octet 1814, octet 2816, and octets 3818. There are 8 bits, numbered 0-7. Octet 1814can store information where, each bit indicates whether an Scell, corresponding to that bit, is activated. Octet 2816can store the following information: bit7can be reserved (R); bit6can store an identifier for direction (D being downlink, and U being uplink); bits5-1can store a logical channel identifier (LCID). Octets 3 818 can store the following information: bits7-2can be reserved (R); and bits1-0can store additional DMRS position indication819. Each octet of octets 3818can correspond to a different Scell (e.g., to Scells indicated by octet 1812).

In additional DMRS position indication820, index822indicates a value stored in bits1-0of octet 2816, and additional DMRS position824indicates a corresponding number of additional DMRS positions.

There are four possible index values in index822, and those four values can be expressed in binary in the two bits of bits1-0of octet 2816.

In MAC-CE message830, bit832indicates a bit number for octets 1834, octet 2836, and octets 3838. There are 8 bits, numbered 0-7. Octets 1834can store information where each bit indicates whether a Scell that corresponds to that bit is activated. Octet 2836can store the following information: bit7can be reserved (R); bit6can store an identifier for direction (D being downlink, and U being uplink); bits5-1can store a logical channel identifier (LCID). Octets 3838can store the following information: bits7-2can be reserved (R); and bits1-0can store additional DMRS position indication839. Each octet of octets 3838can correspond to a different Scell (e.g., to Scells indicated by octet 1832).

Put another way, a MAC-CE for activation/deactivation of additional DMRS information can be implemented as follows.

For activation/deactivation of additional DMRS information, a MAC-CE with a highest ServCellIndex of a serving cell with configured downlink/uplink less than 8, the MAC-CE can be configured as follows.

Ci(e.g., C1-C7) can indicate whether there is a Scell configured for the MAC entity with ScellIndex i. This field can indicate the activation/deactivation status of the Scell with ScellIndex i, and in other cases the MAC entity can ignore the Cifield. The Cifield can be set to 1 to indicate that the Scell with ScellIndex i shall be activated. The Cifield can be set to 0 to indicate that the Scell with ScellIndex i shall be deactivated.

Indexci(e.g., Indexc1-Indexc7) can indicate, where the Cifield is set to 1, that dynamic additional DMRS configuration is configured for ScellIndex i.

In some examples, R can be a reserved bit, and set to 0.

D/U can indicate that, where it is set to 1 that means that MAC-CE is triggered in a downlink direction, and where it is set to 0 that means that MAC-CE is triggered for an uplink direction.

For activation/deactivation of additional DMRS information, a MAC-CE with a highest ServCellIndex of a serving cell with configured downlink/uplink between 8 and 31 (inclusive), the MAC-CE can be configured as follows. In general, this MAC-CE can be similar to the MAC-CE for no more than 7 serving cells, but with C1-C31and Indexc1-Indexc31, instead of with C1-C7and Indexc1-Indexc7.

FIGS.9A and9Billustrate an example signal flow900for attaching with downlink secondary cell activation, and downlink data flow that triggers additional DMRS using MAC-CE. As depicted, in signal flow900, communications are sent between user equipment902, gNB904, and 5G core (5GC)906(which comprises access and mobility management function (AMF)908and user plane function (UPF)910).

The signal flow of signal flow900is an example signal flow, and there can be signal flows that implement different signals, or the signals of signal flow900in a different order, as part of facilitating dynamic additional DMRS configuration.

As depicted in signal flow900, the following occurs:5G-NR RRC connection setup912Msg1: Preamble914Allocate temporary Cell Radio Network Temporary Identifier (C-RNTI)916PDCCH DCI Format 1_0 [Random Access RNTI (RA_RNTI)]918Msg2: Random Access Response920Msg3: RRCSetupRequest922PDCCH DCI Format 1_0 [C_RNTI]924Msg4:RRCSetup926, where a dynamicAdditionalDmrsSupport[TRUE/FALSE] IE is contained in this message, and can be added as part of the present techniquesPDCCH DCI Format 0_0 [C_RNTI]928RRCSetupComplete930AMF Selection932Initial UE message [Non-Access-Stratum-Protocol Data Unit (NAS-PDU); Registration Request]934NAS Identity Request/Response936NAS Authentication Request/Response938NAS Security Mode Command/Complete940UE capability enquiry941AUE capability information, with dynamicAdditionalDmrsSupport[Supported] IE in FeatureSetDownlink and/or FeatureSetUplink941B· Initial Context Setup Request [NAS-PDU:Registration Accept]942RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PDSCH-Config IE where UE supports this feature in downlink944(which can indicate that the UE already supports a dynamic additional DMRS feature that is communicated by the UE in941B as part of UE capability information; here, a gNB can add this IE in a RRCE Reconfiguration message)RRCReconfigurationComplete946Initial Context Setup Response948Standalone (SA) UE attach procedure completed950Downlink secondary cells activation procedure951ACondition met to activate secondary cells951BTrigger Scell activation MAC-CE951CDownlink data951DDownlink data951EPDCCH DCI Format 1_1 for Pcell [C_RNTI]951FPDCCH DCI Format 1_1 for Scell [C_RNTI]951GDownlink data for Pcell [MAC PDU contains PDSCH]951HDownlink data for Scell [MAC PDU contains PDSCH]951IStart downlink data transfer and channel quality reporting for Pcell and/or Scells952Downlink data954Downlink data956PDCCH DCI Format 1_1 [C_RNTI]958Downlink Data for Pcell [MAC PDU contains PDSCH]960ADownlink Data for Scell [MAC PDU contains PDSCH]960AStart downlink data transfer and channel quality reporting for Pcell and/or Scells961ADownlink data961BDownlink data961CPcell PDCCH DCI format 1_1 [C_RNTI]961DPcell downlink data [MAC PDU contains PDSCH]961EScell PDCCH DCI format 1_1 [C_RNTI]961FScell downlink data [MAC PDU contains PDSCH]961GPcell HARQ Feedback=ACK962AScell HARQ feedback=ACK962BPcell Channel State Information (CSI) Report [CQI=15]964AScell CSI Report [CQI=15]964BDL data decoding failed at UE for Pcell and/or Scells966CSI Report for Pcell and/or Scells [CQI=9, 7, 6, . . . ]968Channel condition gets worse970CSI Report for Pcell and/or Scells [CQI=4, 5, 1, . . . ]572PDCCH DCI Format 1_1 for Pcell and Scells [C_RNTI]974Downlink Data for Pcell and Scells [MAC PDU contains PDSCH]976Pcell and Scell HARQ Feedback=NACK978Pcell and Scell HARD Feedback=DTX980Trigger/change additional DMRS configuration in DL DCI because condition met for Pcell and/or Scells982, where, in some examples, a condition can be CQI reporting is bad for a certain threshold and period; HARQ feedback is reported as NACK (e.g., BLER is high for a certain threshold and period); UE is on a cell edge; and/or UE is on high mobilityDownlink Data984UE decodes new MAC-CE received for downlink direction on Pcell and Scells985ATrigger activation/deactivation of additional DMRS information MAC-CE for Pcell985B (with a MAC-CE according to the present techniques)Trigger activation/deactivation of additional DMRS information MAC-CE for Scell985C (with a MAC-CE according to the present techniques)HARQ feedback=ACK for MAC-CE985DDetermine TB for PDSCH by considering additional DMRS information for Pcell and Scells985EPcell and Scell PDCCH DCI Format 1_1986Pcell and Scell Downlink Data [MAC PDU contains PDSCH]988Pcell and Scells HARQ Feedback=ACK990Downlink Data992ADownlink data on Pcell and Scells992BImprovement seen in UE throughput for DL Data994DL Data transfer continues996

FIGS.10A and10Billustrate an example signal flow for dynamic additional DMRS configuration for a uplink, and that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure.

As depicted, in signal flow1000, communications are sent between user equipment1002, gNB1004, and 5GC1006(which comprises AMF1008and UPF1010).

The signal flow of signal flow1000is an example signal flow, and there can be signal flows that implement different signals, or the signals of signal flow1000in a different order, as part of facilitating dynamic additional DMRS configuration.

As depicted in signal flow1000, the following occurs:5G-NR RRC connection setup1012Msg1: Preamble1014Allocate temporary C-RNTI1016PDCCH DCI Format 1_0 [RA_RNTI]1018Msg2: Random Access Response1020Msg3: RRCSetupRequest1022PDCCH DCI Format 1_0 [C_RNTI]1024Msg4:RRCSetup1026, where a dynamicAdditionalDmrsSupport[TRUE/FALSE] IE is contained in this message, and can be added as part of the present techniquesPDCCH DCI Format 0_0 [C_RNTI]1028RRCSetupComplete1030AMF Selection1032Initial UE message [NAS-PDU:Registration Request]1034NAS Identity Request/Response1036NAS Authentication Request/Response1038NAS Security Mode Command/Complete1040UE capability enquiry1041AUE capability information, with dynamicAdditionalDmrsSupport[Supported] IE in FeatureSetUplink1041B (or dynamicAdditionalDmrsSupport[Supported] IE in FeatureSetDownlink for downlink)Initial Context Setup Request [NAS-PDU:Registration Accept]1042RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PDSCH-Config IE where UE supports this feature in uplink1044RRCReconfigurationComplete1046Initial Context Setup Response1048SA UE attach procedure completed1050Uplink secondary cells activation procedure1051ACondition met to activate secondary cells1051BTrigger Scell activation MAC-CE1051CPDCCH DCI format 0_1 for Pcell [C_RNTI]1051DPDCCH DCI format 0_1 for Scell [C_RNTI]1051EUplink data on Pcell [MAC PDU contains PUSCH]1051FUplink data on Scell(s) [MAC PDU contains PUSCH]1051GUplink data1051HUplink data1051IStart uplink data transfer and channel quality reporting1052Uplink data1054Uplink data1056PDCCH DCI Format 0_1 on Pcell [C_RNTI]1058AUplink Data on Pcell [MAC PDU contains PDSCH]1058BPDCCH DCI Format 0_1 on Scell [C_RNTI]1060AUplink Data on Scell [MAC PDU contains PDSCH]1060BCRC status=PASS for UL PUSCH data for Pcell and Scell1062Uplink data1064Uplink data1066CSI Report for Pcell and Scells [SNR>=10]1068UL data decoding failed at gNB for Pcell and/or Scells1070CSI Report for Pcell and Scells [SNR=5, 4, . . . ]1072Channel condition getting worse1074CSI Report for Pcell and Scells [SNR=4, 2, 1, 0, −1, . . . ]1076PDCCH DCI Format 0_1 for Pcell and Scells [C_RNTI]1078Uplink Data on Pcell and Scells [MAC PDU contains PUSCH]1080CRC Status=FAIL for UL PUSCH because of low SNR for Pcell and/or Scells1082Trigger/change additional DMRS configuration in UL DCI because of a condition for Pcell and Scells1084, where, in some examples, a condition can be UL SNR reporting is bad for a certain threshold and period; UL CRC fails because SNR is low (e.g., BLER is high for a certain threshold and period); UE is on a cell edge; and/or UE is on high mobilityUplink data on Pcell and Scells1086UE decodes new MAC-CE received for UL direction for Pcell and Scells1088ATrigger activation/deactivation of additional DMRS information MAC-CE for Pcell1088B (with a MAC-CE according to the present techniques)Trigger activation/deactivation of additional DMRS information MAC-CE for Scell1088C (with a MAC-CE according to the present techniques)HARQ feedback=ACK for MAC-CE1088DDetermine TB for PDSCH by considering additional DMRS information for Pcell and Scells1088EPDCCH DCI Format 0_1 for Pcell and Scells [C-RNTI]1088FUplink data on Pcell and Scells [MAC PDU contains PUSCH]1090CRC Status=PASS for UL PUSCH data for Pcell and Scells1092Uplink data on Pcell1094AUplink data on Scell1094BUplink data1094CImprovement seen in CRC Pass for UL Data on Pcell and Scells1096UL Data transfer continues1098

Example Process Flows

FIG.11illustrates an example process flow1100that can facilitate dynamic additional DMRS configuration, in accordance with an embodiment of this disclosure. In some examples, one or more embodiments of process flow1100can be implemented by gNB904ofFIGS.9A and9B, gNB1004ofFIGS.10A and10B, and/or computing environment1500ofFIG.15.

Process flow1100begins with1102, and moves to operation1104.

Operation1104depicts configuring a first number of demodulation reference signal positions in radio resource control information as part of a connection setup with a user equipment that is configured to facilitate first broadband cellular communications. This can comprise a gNB (e.g., gNB904ofFIGS.9A and9B) establishing a connection setup with user equipment (e.g., UE902ofFIGS.9A and9B), where the connection setup can be similar to NR RRC connection setup912and/or NR RRC connection setup1012. The first number of additional demodulation reference signal positions can be the number that are established as part of an attach procedure.

In some examples, operation1104comprises, as part of the attaching the user equipment, sending, to the user equipment, a radio resource control setup message that indicates support of modification of the first number of demodulation reference signal positions after attaching. In some examples, this radio resource control setup message can be similar to Msg4:RRCSetup926, where a dynamicAdditionalDmrsSupport[TRUE/FALSE] IE is contained in this message, and can be added as part of the present techniques ofFIG.9A, and/or Msg4: RRCSetup1026, where a dynamicAdditionalDmrsSupport[TRUE/FALSE] IE is contained in this message, and can be added as part of the present techniques ofFIG.10A.

In some examples, an information element of the radio resource control setup message indicates support of the modification of the first number of demodulation reference signal positions after attaching. That is, within the radio resource control message, a dynamicAdditionalDmrsSupport[TRUE/FALSE] IE can be contained, which indicates whether the base station supports dynamic modification of demodulation reference signal positions.

After operation1104, process flow1100moves to operation1106.

Operation1106depicts, after attaching the user equipment, sending, to the user equipment, a first medium access control control element message indicative of modifying the first number of demodulation reference signal positions to a second number of demodulation reference signal positions for a primary cell. In some examples, this message can be similar to trigger activation/deactivation of additional DMRS information MAC-CE986ofFIG.9B(in a case of downlink communications), and/or trigger activation/deactivation of additional DMRS information MAC-CE1088(in a case of uplink communications). The MAC-CE message can be similar in structure to that depicted with respect toFIGS.8A and8B.

In some examples, operation1106comprises, in response to sending, to the user equipment, the medium access control control element message, receiving, from the user equipment, a hybrid automatic repeat request message that acknowledges the medium access control control element message. In some examples, this hybrid automatic repeat request message can be similar to HARQ Feedback=ACK for MAC-CE988ofFIG.9B, and/or HARQ Feedback=ACK for MAC-CE1090ofFIG.10B.

In some examples, the medium access control control element message indicates triggering activation of demodulation reference signal positions. In some examples, the medium access control control element message indicates triggering deactivation of demodulation reference signal positions. That is, a MAC-CE message can be used for both activating and deactivating additional DRMS positions.

In some examples, operation1106comprises before sending, to the user equipment, the medium access control control element message indicative of modifying the first number of demodulation reference signal positions, receiving, from the user equipment, a user equipment capability message that indicates support for modification of the first number of demodulation reference signal positions after attaching. In some examples, this user equipment capability message can be similar to UE capability information, with dynamicAdditionalDmrsSupport[Supported] IE in FeatureSetDownlink941B ofFIG.9A, and/or UE capability information, with dynamicAdditionalDmrsSupport[Supported] IE in FeatureSetUplink1041B ofFIG.10A.

In some examples, an information element of the user equipment capability message indicates the support for the modification of the first number of demodulation reference signal positions after attaching. That is, within the user equipment capability message, a dynamicAdditionalDmrsSupport[Supported] IE can be contained, which indicates whether the user equipment supports dynamic modification of demodulation reference signal positions.

In some examples, operation1106comprises, before sending, to the user equipment, the medium access control control element message indicative of modifying the first number of demodulation reference signal positions, sending, to the user equipment, a radio resource control reconfiguration message that indicates support of modification of the first number of demodulation reference signal positions after attaching. This radio resource control reconfiguration message can be similar to RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PDSCH-Config IE where UE supports this feature in downlink944, and/or RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PUSCH-Config IE where UE supports this feature in uplink1044.

This radio resource control reconfiguration message can indicate that the UE already supports a dynamic additional DMRS feature that is communicated by the UE in941B or1041B as part of UE capability information. Here, a gNB can add this IE in a RRC Reconfiguration message.

In some examples, a physical downlink shared channel configuration information element of the radio resource control reconfiguration message indicates support of the modification of the first number of demodulation reference signal positions in downlink communications. That is, the IE can be similar to PDSCH-Config IE in RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PDSCH-Config IE where UE supports this feature in downlink944.

In some examples, a physical uplink shared channel configuration information element of the radio resource control reconfiguration message indicates support of the modification of the first number of demodulation reference signal positions in uplink communications. That is, the IE can be similar to PUSCH-Config IE in RRCReconfiguration with dynamicAdditionalDmrsSupport=TRUE in PUSCH-Config IE where UE supports this feature in uplink1044.

After operation1106, process flow1100moves to operation1108.

Operation1108depicts, in response to determining that a secondary cell is activated with respect to the user equipment, sending, to the user equipment, a second medium access control control element message indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for the secondary cell. In some examples, operation1108can be implemented in a similar manner as operation1106, with regard to a secondary cell in operation1108as opposed to with regard to a primary cell in operation1106.

In some examples, determining that a secondary cell is activated with respect to user equipment can be performed based on determining that downlink secondary cells activation procedure951A ofFIG.9Aor uplink secondary cells activation procedure1051A ofFIG.10Ahas been performed.

In some examples, a group of secondary cells that comprises the secondary cell is activated with respect to the user equipment. That is, it can be that multiple Scells are activated.

In some examples, the second medium access control control element message is indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for each secondary cell of the group of secondary cells. In some examples, each secondary cell of the group of secondary cells is configured to use a same number of demodulation reference signal positions. That is, when Scells are configured for additional DMRS signal positions, they can all be configured in the same way (among the Scells that have additional DMRS signal positions enabled).

In some examples, the group of secondary cells comprises a first subgroup of secondary cells for which additional demodulation reference signal positions are enabled, and a second subgroup of secondary cells for which the additional demodulation reference signal positions are not enabled, and the second medium access control control element message is indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for each secondary cell of the first subgroup of secondary cells, and further indicative of an absence of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for each secondary cell of the second subgroup of secondary cells. That is, there can be some Scells for which additional DMRS signal positions are enabled (e.g., the first subgroup of secondary cells), and some Scells for which additional DMRS signal positions are not enabled (e.g., the second subgroup of secondary cells). In such examples, it can be that the number of additional DMRS signal positions are modified for the first subgroup of secondary cells, and not modified for the second subgroup of secondary cells.

In some examples, operation1108comprises configuring the second medium access control control element message according to a first format in response to a number of secondary cells in a group of secondary cells that comprises the secondary cell being determined to be less than or equal to a criterion threshold applicable to secondary cells, or configuring the second medium access control control element message according to a second format in response to the number of secondary cells in the group of secondary cells that comprises the secondary cell being determined to be greater than the criterion threshold. In some examples, the criterion threshold is a first criterion threshold, and wherein configuring the second medium access control control element message according to the second format is performed in response to the number of secondary cells being determined to be less than or equal to a second criterion threshold.

That is, different types of MAC-CE messages can be sent based on a number of Scells that are activated. Using the example ofFIGS.8A and8B, MAC-CE message810can be used when the number of Scells that are activated is up to 7, and MAC-CE message830can be used when the number of Scells that are activated ranges between 8-31, inclusive.

It can be appreciated that there can be examples where the different types of MAC-CE messages are used for different number of activated Scells than 1-7 and 8-31.

After operation1108, process flow1100moves to operation1110.

Operation1110depicts conducting second broadband cellular communications with the user equipment according to the second number of demodulation reference signal positions, wherein a throughput of the second broadband cellular communications is determined as a function of a size of a transport block set based on the second number of demodulation reference signal positions. This can comprise the gNB using the dynamically configured additional DMRS positions, such as in DL data transfer continues996ofFIG.9B(in a case of downlink communications), and/or UL data transfer continues1098ofFIG.10B(in a case of uplink communications).

In some examples, the user equipment is a first user equipment, the primary cell is a first primary cell, the secondary cell is a first secondary cell, and operation1110comprises sending, to a second user equipment, a third medium access control control element message indicative of modifying a third number of demodulation reference signal positions to a fourth number of demodulation reference signal positions for a second primary cell, and in response to determining that no second secondary cell is activated with respect to the first user equipment, refraining from sending, to the first user equipment, a fourth medium access control control element message indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for the second secondary cell. That is, there can be examples where a second UE does not have Scells activated, so when modifying the number of additional DMRS signal positions for this second UE, a gNB can omit sending a message indicative of modifying the number of additional DMRS signal positions for Scells.

FIG.12illustrates an example process flow1200that can facilitate dynamic additional DMRS configuration, in accordance with an embodiment of this disclosure. In some examples, one or more embodiments of process flow1200can be implemented by gNB904ofFIGS.9A and9B, gNB1004ofFIGS.10A and10B, and/or computing environment1500ofFIG.15.

It can be appreciated that the operating procedures of process flow1200are example operating procedures, and that there can be embodiments that implement more or fewer operating procedures than are depicted, or that implement the depicted operating procedures in a different order than as depicted. In some examples, process flow1200can be implemented in conjunction with one or more embodiments of one or more of process flow1100ofFIG.11, and/or process flow1300ofFIG.13.

Process flow1200begins with1202, and moves to operation1204.

Operation1204depicts, after attaching a user equipment that is configured to facilitate first broadband cellular communications, sending, by a system comprising a processor, and to the user equipment, a first medium access control control element message indicative of a first number of demodulation reference signal positions that was established as part of a connection setup being modified to a second number of demodulation reference signal positions for a primary cell. In some examples, operation1204can be implemented in a similar manner as operations1104-1106ofFIG.11.

In some examples, the second number of demodulation reference signal positions is configured for uplink communications of the broadband cellular communications, and sending the message to the user equipment is performed in response to receiving uplink data from the user equipment. That is, the additional DMRS positions can be changed for uplink communications, and determining to change the additional DMRS positions can be made based on uplink data.

In some examples, the uplink data indicates that an uplink signal-to-noise ratio metric does not satisfy a threshold associated with a predetermined quality criterion for a defined amount of time, wherein a cyclic redundancy check that corresponds to the uplink data has failed or is failing, wherein the uplink data indicates that the system is connected to edge network equipment of a cellular network via which the broadband cellular communications are conducted, or wherein the uplink data indicates that the system satisfies a defined physical movement criterion.

After operation1204, process flow1200moves to operation1206.

Operation1206depicts in response to determining that a secondary cell is activated with respect to the user equipment, sending, by the system and to the user equipment, a second medium access control control element message indicative of modifying the first number of demodulation reference signal positions to the second number of demodulation reference signal positions for the secondary cell. In some examples, operation1206can be implemented in a similar manner as operation1108ofFIG.11.

In some examples, operation1206comprises, in response to sending, to the user equipment, the first medium access control control element message and the second medium access control control element message, receiving, by the system and from the user equipment, a hybrid automatic repeat request message that acknowledges the first medium access control control element message and the second medium access control control element message. That is, in some examples, UE can send HARQ feedback for a Pcell MAC-CE and a Scell MAC-CE to the Pcell only.

In some examples, operation1206comprises, in response to sending, to the user equipment, the first medium access control control element message, receiving by the primary cell and from the user equipment, a first hybrid automatic repeat request message that acknowledges the first medium access control control element message, and, in response to sending, to the user equipment, the second medium access control control element message, receiving by the secondary cell and from the user equipment, a second hybrid automatic repeat request message that acknowledges the second medium access control control element message. That is, in some examples, UE can send HARQ feedback for a Pcell MAC-CE to the Pcell, and send HARD feedback for a s Scell MAC-CE to the Scell. After operation1206, process flow1200moves to operation1208.

Operation1208depicts conducting broadband cellular communications with the user equipment according to the second number of demodulation reference signal positions. In some examples, operation1208can be implemented in a similar manner as operation1110ofFIG.11.

FIG.13illustrates an example process flow1300that can facilitate dynamic additional DMRS configuration, in accordance with an embodiment of this disclosure. In some examples, one or more embodiments of process flow1300can be implemented by gNB904ofFIGS.9A and9B, gNB1004ofFIGS.10A and10B, and/or computing environment1500ofFIG.15.

Process flow1300begins with1302, and moves to operation1304.

Operation1304depicts, after attaching a user equipment that is configured to facilitate first broadband cellular communications, sending, to the user equipment, a first medium access control control element message indicative of a modified number of demodulation reference signal positions that was established as part of a connection setup for a primary cell. In some examples, operation1304can be implemented in a similar manner as operations1104-1106ofFIG.11.

In some examples, modifying the number of demodulation reference signal positions is performed for downlink communications of the broadband cellular communications, and wherein the sending, to the user equipment, the message is performed in response to receiving downlink data from the user equipment. Additional DMRS positions can be changed for downlink communications, and a determination to change additional DMRS positions can be based on downlink data. That is, when there is downlink data transmission and a gNB receives too many HARQ feedback failures (e.g., the gNB receives NACK or DTX messages), or low CQI reporting from a UE, it can mean that the UE is on cell edge, and the UE lacks sufficient power or signal conditions to send HARQ feedback as ACK.

In some examples, the downlink data indicates that a continuous quality improvement reporting metric does not satisfy a threshold associated with a defined threshold criterion for a defined amount of time. That is, CQI reporting can be bad for a defined threshold value and time period.

In some examples, the downlink data indicates that hybrid automatic feedback is being reported as a negative acknowledgement. That is, HARQ feedback can be reported as NACK.

In some examples, the downlink data indicates that hybrid automatic feedback is being reported as the negative acknowledgement based on a block error rate metric satisfying a threshold associated with a defined threshold criterion for a defined amount of time, that there is a connection to edge network equipment of a cellular network via which the first broadband cellular communications are conducted, or that a defined high mobility criterion is satisfied. That is, BLER can be high for a defined threshold value and time period; the UE can be located on cell edge; or the UE can be on high mobility.

After operation1304, process flow1300moves to operation1306.

Operation1306depics, in response to determining that a secondary cell is activated with respect to the user equipment, sending, to the user equipment, a second medium access control control element message indicative of the modified number of demodulation reference signal positions for the secondary cell. In some examples, operation1306can be implemented in a similar manner as operation1108ofFIG.11.

After operation1306, process flow1300moves to operation1308.

Operation1308depicts conducting broadband cellular communications with the user equipment according to the modified number of demodulation reference signal positions. In some examples, operation1308can be implemented in a similar manner as operation1110ofFIG.11.

In some examples, the broadband cellular communications are second broadband cellular communications, modifying the number of demodulation reference signal positions comprises modifying the number of demodulation reference signal positions from a first number of demodulation reference signal positions to a second number of demodulation reference signal positions, and a second throughput of the second broadband cellular communications is less than a first throughput of a first broadband cellular communication that is conducted according to the first number of demodulation reference signal positions. That is, data throughput can be inversely proportional to a number of configured additional DMRS positions, where a larger number of additional DMRS symbols indicates a smaller data throughput.

Example Architecture

FIG.14illustrates an example system architecture1400that can facilitate dynamic additional DMRS configuration in accordance with an embodiment of this disclosure. In some examples, part(s) of system architecture can be used to implement the signal flows ofFIGS.9A,9B,10A,10B, and/or the process flows ofFIGS.11-13.

As depicted, system architecture1400comprises gNB1402, Pcell1404, Scell(s)1406, UE1408, and dynamic additional demodulation reference signal configuration component1410. In some examples, gNB1402can be similar to gNB702ofFIG.7, and UE1408can be similar to UE704. Pcell1404can be a Pcell as described herein, and that is communicatively coupled to both gNB1402and UE1408. Similarly, Scell(s)1406can be one or more Scells as described herein, and that are communicatively coupled to both gNB1402and UE1408.

Dynamic additional demodulation reference signal configuration component1410can comprise a component of gNB1402that facilitates dynamic additional demodulation reference signal configuration as described herein, and can do so in a scenario where carrier aggregation of Pcell1404and Scell(s)1406is enabled.

Example Operating Environment

In order to provide additional context for various embodiments described herein,FIG.15and the following discussion are intended to provide a brief, general description of a suitable computing environment1500in which the various embodiments of the embodiment described herein can be implemented.

In some examples, computing environment1500can implement one or more embodiments of the process flows ofFIGS.11-13to facilitate dynamic additional DMRS configuration.

While the embodiments have been described above in the general context of computer-executable instructions that can run on one or more computers, those skilled in the art will recognize that the embodiments can be also implemented in combination with other program modules and/or as a combination of hardware and software.

With reference again toFIG.15, the example environment1500for implementing various embodiments described herein includes a computer1502, the computer1502including a processing unit1504, a system memory1506and a system bus1508. The system bus1508couples system components including, but not limited to, the system memory1506to the processing unit1504. The processing unit1504can be any of various commercially available processors. Dual microprocessors and other multi-processor architectures can also be employed as the processing unit1504.

The system bus1508can be any of several types of bus structure that can further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and a local bus using any of a variety of commercially available bus architectures. The system memory1506includes ROM1510and RAM1512. A basic input/output system (BIOS) can be stored in a nonvolatile storage such as ROM, erasable programmable read only memory (EPROM), EEPROM, which BIOS contains the basic routines that help to transfer information between elements within the computer1502, such as during startup. The RAM1512can also include a high-speed RAM such as static RAM for caching data.

The computer1502further includes an internal hard disk drive (HDD)1514(e.g., EIDE, SATA), one or more external storage devices1516(e.g., a magnetic floppy disk drive (FDD)1516, a memory stick or flash drive reader, a memory card reader, etc.) and an optical disk drive1520(e.g., which can read or write from a CD-ROM disc, a DVD, a BD, etc.). While the internal HDD1514is illustrated as located within the computer1502, the internal HDD1514can also be configured for external use in a suitable chassis (not shown). Additionally, while not shown in environment1500, a solid state drive (SSD) could be used in addition to, or in place of, an HDD1514. The HDD1514, external storage device(s)1516and optical disk drive1520can be connected to the system bus1508by an HDD interface1524, an external storage interface1526and an optical drive interface1528, respectively. The interface1524for external drive implementations can include at least one or both of Universal Serial Bus (USB) and Institute of Electrical and Electronics Engineers (IEEE) 1394 interface technologies. Other external drive connection technologies are within contemplation of the embodiments described herein.

A number of program modules can be stored in the drives and RAM1512, including an operating system1530, one or more application programs1532, other program modules1534and program data1536. All or portions of the operating system, applications, modules, and/or data can also be cached in the RAM1512. The systems and methods described herein can be implemented utilizing various commercially available operating systems or combinations of operating systems.

Computer1502can optionally comprise emulation technologies. For example, a hypervisor (not shown) or other intermediary can emulate a hardware environment for operating system1530, and the emulated hardware can optionally be different from the hardware illustrated inFIG.15. In such an embodiment, operating system1530can comprise one virtual machine (VM) of multiple VMs hosted at computer1502. Furthermore, operating system1530can provide runtime environments, such as the Java runtime environment or the .NET framework, for applications1532. Runtime environments are consistent execution environments that allow applications1532to run on any operating system that includes the runtime environment. Similarly, operating system1530can support containers, and applications1532can be in the form of containers, which are lightweight, standalone, executable packages of software that include, e.g., code, runtime, system tools, system libraries and settings for an application.

A monitor1546or other type of display device can be also connected to the system bus1508via an interface, such as a video adapter1548. In addition to the monitor1546, a computer typically includes other peripheral output devices (not shown), such as speakers, printers, etc.

The computer1502can operate in a networked environment using logical connections via wired and/or wireless communications to one or more remote computers, such as a remote computer(s)1550. The remote computer(s)1550can be a workstation, a server computer, a router, a personal computer, portable computer, microprocessor-based entertainment appliance, a peer device or other common network node, and typically includes many or all of the elements described relative to the computer1502, although, for purposes of brevity, only a memory/storage device1552is illustrated. The logical connections depicted include wired/wireless connectivity to a local area network (LAN)1554and/or larger networks, e.g., a wide area network (WAN)1556. Such LAN and WAN networking environments are commonplace in offices and companies, and facilitate enterprise-wide computer networks, such as intranets, all of which can connect to a global communications network, e.g., the Internet.

When used in a LAN networking environment, the computer1502can be connected to the local network1554through a wired and/or wireless communication network interface or adapter1558. The adapter1558can facilitate wired or wireless communication to the LAN1554, which can also include a wireless access point (AP) disposed thereon for communicating with the adapter1558in a wireless mode.

When used in a WAN networking environment, the computer1502can include a modem1560or can be connected to a communications server on the WAN1556via other means for establishing communications over the WAN1556, such as by way of the Internet. The modem1560, which can be internal or external and a wired or wireless device, can be connected to the system bus1508via the input device interface1544. In a networked environment, program modules depicted relative to the computer1502or portions thereof, can be stored in the remote memory/storage device1552. It will be appreciated that the network connections shown are example and other means of establishing a communications link between the computers can be used.

When used in either a LAN or WAN networking environment, the computer1502can access cloud storage systems or other network-based storage systems in addition to, or in place of, external storage devices1516as described above. Generally, a connection between the computer1502and a cloud storage system can be established over a LAN1554or WAN1556e.g., by the adapter1558or modem1560, respectively. Upon connecting the computer1502to an associated cloud storage system, the external storage interface1526can, with the aid of the adapter1558and/or modem1560, manage storage provided by the cloud storage system as it would other types of external storage. For instance, the external storage interface1526can be configured to provide access to cloud storage sources as if those sources were physically connected to the computer1502.

CONCLUSION

In the subject specification, terms such as “datastore,” data storage,” “database,” “cache,” and substantially any other information storage component relevant to operation and functionality of a component, refer to “memory components,” or entities embodied in a “memory” or components comprising the memory. It will be appreciated that the memory components, or computer-readable storage media, described herein can be either volatile memory or nonvolatile storage, or can include both volatile and nonvolatile storage. By way of illustration, and not limitation, nonvolatile storage can include ROM, programmable ROM (PROM), EPROM, EEPROM, or flash memory. Volatile memory can include RAM, which acts as external cache memory. By way of illustration and not limitation, RAM can be available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). Additionally, the disclosed memory components of systems or methods herein are intended to comprise, without being limited to comprising, these and any other suitable types of memory.