Patent Description:
The present disclosure relates generally to communication systems, and more particularly, to dynamically conveyance of information regarding demodulation reference signal (DM-RS) and phase noise compensation reference signal (PC-RS).

An example telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband access through improved spectral efficiency, lowered costs, and improved services using OFDMA on the downlink, SC-FDMA on the uplink, and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology.

DM-RS symbols may be inserted in physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) for channel estimation. Data may be decoded after decoding the DM-RS symbols. It may be preferable to insert DM-RS symbols in the beginning of the PDSCH/PUSCH from a latency perspective. However, in a fast time varying channel, estimated channel may become redundant or invalid for data carried near the end of PDSCH/PUSCH if DM-RS symbols are placed at the beginning of PDSCH/PUSCH.

<CIT> describes systems and/or methods of communicating a wireless orthogonal-frequency-division-multiplexing (OFDM) signal. For example, a wireless communication device may communicate a wireless communication OFDM signal including a plurality of data subcarriers carrying data, at least one pilot subcarrier carrying a reference, predefined, value, and a plurality of zero subcarriers, carrying a zero value, surrounding the pilot subcarrier and separating between the pilot subcarrier and the data subcarriers.

The <NPL>, relates to initial views on numerology for NR access technology and discloses preliminary evaluation results regarding different subcarrier-spacing as well as initial views regarding possible numerology parameters for the NR access technology.

The <NPL>, relates to impact of scalable bandwidth and multiple camping positions on modulation. Said draft proposes to slightly modify the modulation parameters of the OFDMA and SC-FDMA transmission concepts presented in 3GPP TR <NUM> v1. <NUM>, "Physical layer aspects for Evolved UTRA, so as to facilitate the processing of UEs with different frequency domain capabilities and different camping positions.

There is still a need for improved reference signal schemes.

The present invention provides a solution according to the subject matter of the independent claims.

It may be preferable to insert DM-RS symbols in the beginning of PDSCH/PUSCH from a latency perspective. However, in a fast time-varying channel, estimated channel may become redundant or invalid for data carried near the end of PDSCH/PUSCH if DM-RS symbols are placed at the beginning of PDSCH/PUSCH, respectively. Therefore, placing DM-RS symbols in two parts of the PDSCH/PUSCH may be desirable.

The macro cells include eNBs.

A network that includes both small cell and macro cells may be known as a heterogeneous network. The communication links <NUM> may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The base stations <NUM> / UEs <NUM> may use spectrum up to Y MHz (e.g., <NUM>, <NUM>, <NUM>, <NUM>) 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).

When operating in an unlicensed frequency spectrum, the small cell <NUM>' may employ LTE and use the same <NUM> unlicensed frequency spectrum as used by the Wi-Fi AP <NUM>. The small cell <NUM>', employing LTE in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. LTE in an unlicensed spectrum may be referred to as LTE-unlicensed (LTE-U), licensed assisted access (LAA), or MuLTEfire.

The millimeter wave (mmW) base station <NUM> may operate in mmW frequencies and/or near mmW frequencies in communication with the UE <NUM>.

The IP Services <NUM> may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service (PSS), and/or other IP services. The MBMS Gateway <NUM> may be used to distribute MBMS traffic to the base stations <NUM> belonging to a Multicast Broadcast Single Frequency Network (NMSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The base station may also be referred to as a 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), or some other suitable terminology. The base station <NUM> provides an access point to the EPC <NUM> for a UE <NUM>. Examples of UEs <NUM> include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, or any other similar functioning device.

Referring again to <FIG>, in certain aspects, the UE <NUM> / eNB <NUM> may be configured to dynamically convey (<NUM>) information of DM-RS and/or PC-RS in physical downlink control channel (PDCCH). Details of the operations performed at <NUM> are described below with reference to <FIG>.

<FIG> is a diagram <NUM> illustrating an example of a DL frame structure in LTE. <FIG> is a diagram <NUM> illustrating an example of channels within the DL frame structure in LTE. <FIG> is a diagram <NUM> illustrating an example of an UL frame structure in LTE. <FIG> is a diagram <NUM> illustrating an example of channels within the UL frame structure in LTE. In LTE, a frame (<NUM>) may be divided into <NUM> equally sized subframes. Each subframe may include two consecutive time slots. A resource grid may be used to represent the two time slots, each time slot including one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)). In LTE, for a normal cyclic prefix, an RB contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of <NUM> REs. For an extended cyclic prefix, an RB contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive symbols in the time domain, for a total of <NUM> REs.

As illustrated in <FIG>, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include cell-specific reference signals (CRS) (also sometimes called common RS), UE-specific reference signals (UE-RS), and channel state information reference signals (CSI-RS). <FIG> illustrates CRS for antenna ports <NUM>, <NUM>, <NUM>, and <NUM> (indicated as R<NUM>, R<NUM>, R<NUM>, and R<NUM>, respectively), UE-RS for antenna port <NUM> (indicated as R<NUM>), and CSI-RS for antenna port <NUM> (indicated as R). <FIG> illustrates an example of various channels within a DL subframe of a frame. The physical control format indicator channel (PCFICH) is within symbol <NUM> of slot <NUM>, and carries a control format indicator (CFI) that indicates whether the physical downlink control channel (PDCCH) occupies <NUM>, <NUM>, or <NUM> symbols (<FIG> illustrates a PDCCH that occupies <NUM> symbols). The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH may have <NUM>, <NUM>, or <NUM> RB pairs (<FIG> shows two RB pairs, each subset including one RB pair). The physical hybrid automatic repeat request (ARQ) (HARQ) indicator channel (PHICH) is also within symbol <NUM> of slot <NUM> and carries the HARQ indicator (HI) that indicates HARQ acknowledgement (ACK) / negative ACK (NACK) feedback based on the physical uplink shared channel (PUSCH). The primary synchronization channel (PSCH) is within symbol <NUM> of slot <NUM> within subframes <NUM> and <NUM> of a frame, and carries a primary synchronization signal (PSS) that is used by a UE to determine subframe timing and a physical layer identity. The secondary synchronization channel (SSCH) is within symbol <NUM> of slot <NUM> within subframes <NUM> and <NUM> of a frame, and carries a secondary synchronization signal (SSS) that is used by a UE to determine a physical layer cell identity group number. Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH) is within symbols <NUM>, <NUM>, <NUM>, <NUM> of slot <NUM> of subframe <NUM> of a frame, and carries a master information block (MIB). The MIB provides a number of RBs in the DL system bandwidth, a PHICH configuration, and a system frame number (SFN).

As illustrated in <FIG>, some of the REs carry demodulation reference signals (DM-RS) for channel estimation at the eNB. The UE may additionally transmit sounding reference signals (SRS) in the last symbol of a subframe. The SRS may be used by an eNB for channel quality estimation to enable frequency-dependent scheduling on the UL. <FIG> illustrates an example of various channels within an UL subframe of a frame. A physical random access channel (PRACH) may be within one or more subframes within a frame based on the PRACH configuration. The PRACH may include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. A physical uplink control channel (PUCCH) may be located on edges of the UL system bandwidth.

<FIG> is a block diagram of an eNB <NUM> in communication with a UE <NUM> in an access network.

The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB <NUM>. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB <NUM> on the physical channel.

Similar to the functionality described in connection with the DL transmission by the eNB <NUM>, the controller/processor <NUM> provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator <NUM> from a reference signal or feedback transmitted by the eNB <NUM> may be used by the TX processor <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing.

The UL transmission is processed at the eNB <NUM> in a manner similar to that described in connection with the receiver function at the UE <NUM>.

DM-RS symbols may be inserted in PDSCH or PUSCH for channel estimation. Data may be decoded after decoding the DM-RS pilot signals. It may be preferable to insert DM-RS symbols in the beginning of PDSCH/PUSCH from a latency perspective. However, in a fast time-varying channel, estimated channel may become redundant or invalid for data carried near the end of PDSCH/PUSCH if DM-RS symbols are placed at the beginning of PDSCH/PUSCH, respectively. Therefore, placing DM-RS symbols in two parts of the PDSCH/PUSCH may be desirable.

<FIG> is a diagram illustrating an example of dynamically conveying information of DM-RS in a wireless communication system <NUM>. In this example, the wireless communication system <NUM> includes a base station <NUM> and a UE <NUM>. The base station <NUM> may determine (at <NUM>) at least one of the number of DM-RS symbols (e.g., <NUM> or <NUM>) in a subframe or the locations of the DM-RS symbols in the subframe. For example and in one configuration, there may be only one single DM-RS symbol in a subframe, and that single DM-RS symbol may be placed at the beginning of PDSCH or PUSCH. In another configuration, there may be two DM-RS symbols in a subframe, one of the two DM-RS symbols may be placed at the beginning of PDSCH, and the other DM-RS symbol may be placed in the middle of PDSCH. In yet another configuration, there may be two DM-RS symbols in a subframe, one of the two DM-RS symbols may be placed at the beginning of PUSCH, and the other DM-RS symbol may be placed in the middle of PUSCH. The base station <NUM> may change the number and/or locations of DM-RS symbols dynamically based on information obtained by the base station <NUM> at any particular moment.

Upon the determination of at least one of the number of DM-RS symbols or the locations of the DM-RS symbols within a subframe, the base station <NUM> may transmit (at <NUM>) the determined at least one of the number of DM-RS symbols in a subframe or the locations of DM-RS symbols in the subframe to the UE <NUM>. In one configuration, the determined at least one of the number or locations of DM-RS symbols in a subframe may be dynamically conveyed to the UE <NUM> via PDCCH of the same subframe. In one configuration, one or more bits may be reserved in DCI to convey the at least one of the number or location information of DM-RS symbols to the UE <NUM>. For example and in one configuration, one bit may be reserved in DCI to indicate the number of DM-RS symbols in a subframe. In one configuration, one bit may be reserved in DCI to indicate the locations of DM-RS symbols in a subframe. In another configuration, at least one of the determined number or locations of DM-RS symbols in a subframe are conveyed to the UE <NUM> via RRC signaling.

Once the UE <NUM> receives the at least one of the number or locations of DM-RS symbols within a subframe from the base station <NUM>, the UE <NUM> may decode (at <NUM>) the DM-RS symbols from the subframe based on the at least one of the received number or locations of DM-RS symbols. As a result, the UE <NUM> may be dynamically informed of the base station's decision regarding at least one of the number or locations of DM-RS symbols, thus being able to decode the DM-RS symbols accordingly.

<FIG> is a diagram <NUM> illustrating an example of resource allocation scheme for DM-RS symbols within a subframe. In this example, a single DM-RS symbol <NUM> is placed at the beginning (e.g., the first symbol) of PDSCH. Because data may be decoded after decoding DM-RS symbol, placing the DM-RS symbol <NUM> at the beginning of PDSCH may result in low latency.

<FIG> is a diagram <NUM> illustrating another example of resource allocation scheme for DM-RS symbols within a subframe. In this example, a first DM-RS symbol <NUM> is placed at the beginning (e.g., the first symbol) of PDSCH, and a second DM-RS symbol <NUM> is placed in the middle (e.g., the <NUM>th symbol) of PDSCH. In a fast time-varying channel, the resource allocation scheme illustrated in <FIG> may make channel estimation more accurate. In one configuration, the base station <NUM> described above in <FIG> may switch between the resource allocation schemes illustrated in <FIG> based on information obtained by the base station <NUM> at any particular moment. In one configuration, the number or locations of DM-RS symbols in a subframe conveyed from the base station <NUM> to the UE <NUM> may correspond to one of the resource allocation schemes illustrated in <FIG> that is being used by the base station <NUM>.

Millimeter wave (MMW) radios may have higher phase noise levels than sub-<NUM> radios. This may be due to a higher frequency ratio between local oscillator and temperature compensated crystal oscillator, and noisier voltage controlled oscillators. UEs (e.g., receivers in downlink) may cause the majority of phase noise in a communication system. Phase noise may cause variations in phase over the duration of a single symbol. In the worst case scenario, phase variation within one symbol may be substantial. Phase noise compensation reference signal (PC-RS) may allow a UE to estimate phase noise, thus reducing radio frequency impairments caused by phase noise. A base station may determine different resource allocation schemes for transmitting PC-RS to a UE. A base station may switch from one resource allocation scheme for PC-RS to another resource allocation scheme for PC-RS at times.

<FIG> is a diagram illustrating an example of dynamically conveying information of PC-RS in a wireless communication system <NUM>. In this example, the wireless communication system <NUM> includes a base station <NUM> and a UE <NUM>. The base station <NUM> may determine (at <NUM>) a resource allocation scheme for PC-RS in relation to DM-RS symbols in a subframe. The base station <NUM> may change the resource allocation scheme for PC-RS in relation to DM-RS symbols dynamically based on information obtained by the base station <NUM> at any particular moment.

Upon the determination of the resource allocation scheme for PC-RS in relation to DM-RS symbols within a subframe, the base station <NUM> may transmit (at <NUM>) the determined resource allocation scheme to the UE <NUM>. In one configuration, the determined resource allocation scheme for PC-RS in relation to DM-RS symbols in a subframe may be dynamically conveyed to the UE <NUM> via PDCCH of the same subframe. In one configuration, one or more bits may be reserved in DCI to convey the determined resource allocation scheme to the UE <NUM>. For example and in one configuration, two bits may be reserved in DCI to indicate a particular pattern of resource allocation for PC-RS in relation to DM-RS symbols within a subframe. In another configuration, the determined resource allocation scheme for PC-RS in relation to DM-RS symbols in a subframe may be conveyed to the UE <NUM> via RRC signaling.

Once the UE <NUM> receives the determined resource allocation scheme from the base station <NUM>, the UE <NUM> may decode (at <NUM>) the PC-RS from the subframe based on the received resource allocation scheme for PC-RS in relation to DM-RS symbols within the subframe. As a result, the UE <NUM> may be dynamically informed of the base station's decision regarding the resource allocation scheme for PC-RS in relation to DM-RS symbols within a subframe, thus being able to decode the PC-RS accordingly.

<FIG> is a diagram <NUM> illustrating an example of resource allocation scheme for PC-RS with regard to DM-RS symbols within a subframe. In this example, a single DM-RS symbol <NUM> is placed at the beginning (e.g., the first symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbol <NUM> within a subframe. In one configuration, PC-RS may be punctured by the DM-RS symbol <NUM>, as well as by PDCCH. For example, PC-RS does not occupy resource elements that are assigned to the DM-RS symbol <NUM> and symbols within PDCCH. In one configuration, PC-RS and DM-RS may occupy different symbols of the subframe.

<FIG> is a diagram <NUM> illustrating another example of resource allocation scheme for PC-RS in relation to DM-RS symbols within a subframe. In this example, a first DM-RS symbol <NUM> may be placed at the beginning (e.g., the first symbol) of PDSCH, and a second DM-RS symbol <NUM> may be placed in the middle (e.g., the <NUM>th symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbols <NUM> and <NUM> within a subframe. In one configuration, PC-RS may be punctured by the DM-RS symbols <NUM> and <NUM>, as well as by PDCCH. For example, PC-RS does not occupy resource elements that are assigned to the DM-RS symbols <NUM>, <NUM>, and symbols within PDCCH. In one configuration, PC-RS and DM-RS may occupy different symbols of the subframe.

<FIG> is a diagram <NUM> illustrating an example of resource allocation scheme for PC-RS with regard to DM-RS symbols within a subframe. In this example, a single DM-RS symbol <NUM> may be placed at the beginning (e.g., the first symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbol <NUM> within a subframe. PC-RS may be punctured by PDCCH. In one configuration, the resource element at subcarrier <NUM> of the DM-RS symbol <NUM> may be punctured to accommodate PC-RS in the DM-RS symbol <NUM>. For example, PC-RS may occupy resource element at subcarrier <NUM> of the DM-RS symbol <NUM>.

<FIG> is a diagram <NUM> illustrating another example of resource allocation scheme for PC-RS with regard to DM-RS symbols within a subframe. In this example, a first DM-RS symbol <NUM> may be placed at the beginning (e.g., the first symbol) of PDSCH, and a second DM-RS symbol <NUM> may be placed in the middle (e.g., the <NUM>th symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbols <NUM> and <NUM> within a subframe. PC-RS may be punctured by PDCCH. In one configuration, the resource elements at subcarrier <NUM> of the DM-RS symbols <NUM> and <NUM> may be punctured to accommodate PC-RS in the DM-RS symbols <NUM> and <NUM>. For example, PC-RS may occupy resource elements at subcarrier <NUM> of the DM-RS symbols <NUM> and <NUM>.

<FIG> is a diagram <NUM> illustrating an example of resource allocation scheme for PC-RS with regard to DM-RS symbols within a subframe. In this example, a single DM-RS symbol <NUM> may be placed at the beginning (e.g., the first symbol) of PDSCH. The DM-RS symbol <NUM> may be transmitted in one out of N subcarriers to reduce overhead. In the example in <FIG>, N is equal to <NUM>. But one of ordinary skill in the art would recognize that this is for illustration purpose and N could be <NUM>, <NUM>, <NUM>, or any other positive integer. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarriers <NUM>, <NUM>, and <NUM>. PC-RS may be transmitted in multiple subcarriers to estimate phase trajectory. In one configuration, PC-RS may co-exist with the DM-RS symbol <NUM> within a subframe. PC-RS may be punctured by PDCCH. In one configuration, PC-RS may be rate matched around subcarriers in the DM-RS symbol <NUM>. For example, at the first symbol of PDSCH, PC-RS may occupy resource elements at subcarriers (e.g., <NUM> and <NUM>) that are not used by the DM-RS symbol <NUM>, but may not occupy resource element at subcarrier <NUM> that is used by the DM-RS symbol <NUM>.

<FIG> is a diagram <NUM> illustrating another example of resource allocation scheme for PC-RS with regard to DM-RS symbols within a subframe. In this example, a first DM-RS symbol <NUM> may be placed at the beginning (e.g., the first symbol) of PDSCH, and a second DM-RS symbol <NUM> may be placed in the middle (e.g., the <NUM>th symbol) of PDSCH. The DM-RS symbols <NUM> and <NUM> may be transmitted in one out of N subcarriers to reduce overhead. In the example in <FIG>, N is equal to <NUM>. But one of ordinary skill in the art would recognize that this is for illustration purpose and N could be <NUM>, <NUM>, <NUM>, or any other positive integer. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarriers <NUM>, <NUM>, and <NUM>. PC-RS may be transmitted in multiple subcarriers to estimate phase trajectory. In one configuration, PC-RS may co-exist with the DM-RS symbols <NUM> and <NUM> within a subframe. PC-RS may be punctured by PDCCH. In one configuration, PC-RS may be rate matched around subcarriers in the DM-RS symbols <NUM> and <NUM>. For example, at the first and <NUM>th symbols, PC-RS may occupy resource elements at subcarriers (e.g., <NUM> and <NUM>) that are not used by the DM-RS symbols <NUM> and <NUM>, but may not occupy resource elements at subcarrier <NUM> that are used by the DM-RS symbols <NUM> and <NUM>.

<FIG> is a diagram <NUM> illustrating an example of resource allocation scheme for PC-RS with regard to PDCCH symbols within a subframe. In this example, there are two PDCCH symbols <NUM> and <NUM>, and a single DM-RS symbol <NUM> is placed at the beginning (e.g., the first symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbol <NUM> within a subframe. In one configuration, the PDCCH symbols <NUM> and <NUM> may be punctured to accommodate PC-RS. For example, PC-RS may occupy resource elements at subcarrier <NUM> of the PDCCH symbols <NUM> and <NUM>.

<FIG> is a diagram <NUM> illustrating another example of resource allocation scheme for PC-RS with regard to PDCCH symbols within a subframe. In this example, there are two PDCCH symbols <NUM> and <NUM>, and a first DM-RS symbol <NUM> is placed at the beginning (e.g., the first symbol) of PDSCH, and a second DM-RS symbol <NUM> is placed in the middle (e.g., the <NUM>th symbol) of PDSCH. PC-RS may occupy one or more subcarriers. For example, PC-RS may occupy subcarrier <NUM>. In one configuration, PC-RS may co-exist with the DM-RS symbols <NUM> and <NUM> within a subframe. In one configuration, the PDCCH symbols <NUM> and <NUM> may be punctured to accommodate PC-RS. For example, PC-RS may occupy resource elements at subcarrier <NUM> of the PDCCH symbols <NUM> and <NUM>.

In one configuration, the base station <NUM> described above in <FIG> may switch between the different resource allocation schemes for PC-RS illustrated in <FIG>, <FIG>, <FIG>, <FIG> based on information obtained by the base station <NUM> at any particular moment. In one configuration, the resource allocation schemes for PC-RS illustrated in <FIG>, <FIG>, <FIG>, <FIG> may be the resource allocation scheme for PC-RS conveyed from the base station <NUM> to the UE <NUM>, as described above with reference to <FIG>.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by an eNB (e.g., the eNB <NUM>, <NUM>, <NUM>, <NUM>, or the apparatus <NUM>/<NUM>'). At <NUM>, the eNB may determine at least one of the number of one or more DM-RS symbols in a subframe or one or more locations within the subframe for transmission of the one or more DM-RS symbols. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

In one configuration, the number of the one or more DM-RS symbols may be one. In such a configuration, the one or more locations may include the first symbol of PDSCH/PUSCH. In one configuration, the number of the one or more DM-RS symbols may be two. In such a configuration, the one or more locations may include a first location at the beginning of PDSCH/PUSCH and a second location in the middle of PDSCH/PUSCH. The first location and the second location may be separated by at least one symbol. In one configuration, the one or more DM-RS symbols may be inserted in PDSCH/PUSCH for channel estimation.

At <NUM>, the eNB may transmit the at least one of the number of the one or more DM-RS symbols or the one or more locations within the subframe for the transmission of the one or more DM-RS symbols to a UE. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

In one configuration, the at least one of the number of DM-RS symbols or the one or more locations for transmission of the DM-RS symbols may be dynamically transmitted to the UE via PDCCH. In such a configuration, one or more bits may be reserved in DCI to identify the at least one of the number of the DM-RS symbols or the one or more locations within the subframe for transmission of the DM-RS symbols. In one configuration, the at least one of the number or the locations of DM-RS symbols may be transmitted to the UE via RRC signaling.

At <NUM>, the eNB may optionally determine a resource allocation scheme for PC-RS with regard to the one or more DM-RS symbols co-existing in the same subframe. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>. In one configuration, PDCCH may be punctured to accommodate PC-RS.

At <NUM>, the eNB may optionally transmit the resource allocation scheme for PC-RS with regard to the one or more DM-RS symbols to the UE. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

In one configuration, the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols may be transmitted to the UE dynamically via PDCCH. In such a configuration, one or more bits may be reserved in DCI to identify the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols. In one configuration, the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols may be transmitted to the UE via RRC signaling.

In one configuration, the resource allocation scheme (e.g., the resource allocation scheme described above in <FIG>) may inform the UE to rate match the PC-RS around subcarriers of the one or more DM-RS symbols. In one configuration, the resource allocation scheme (e.g., the resource allocation scheme described above in <FIG>) may inform the UE to puncture the one or more DM-RS symbols in subcarriers that are reserved for the PC-RS. In one configuration, the resource allocation scheme (e.g., the resource allocation scheme described above in <FIG>) may inform the UE to puncture the PC-RS in the one or more DM-RS symbols.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an exemplary apparatus <NUM>. The apparatus <NUM> may be an eNB. The apparatus <NUM> may include a reception component <NUM> that receives uplink information from a UE <NUM>. The apparatus may include a transmission component <NUM> that transmits downlink information to the UE <NUM>. The reception component <NUM> and the transmission component <NUM> may work together to coordinate communications of the apparatus <NUM>.

The apparatus <NUM> may include a DM-RS scheduling component <NUM> that determines the resource allocation scheme (e.g., at least one of the number or locations) for DM-RS symbols. In one configuration, the DM-RS scheduling component <NUM> may perform operations described above with reference to <NUM> of <FIG>. The DM-RS scheduling component <NUM> may send the determined at least one of number or locations of DM-RS symbols to the transmission component <NUM> for conveyance to the UE <NUM>.

The apparatus <NUM> may optionally include a PC-RS scheduling component <NUM> that determines the resource allocation scheme for PC-RS. In one configuration, the PC-RS scheduling component <NUM> may perform operations described above with reference to <NUM> of <FIG>. The PC-RS scheduling component <NUM> may send the determined resource allocation scheme for PC-RS to the transmission component <NUM> for conveyance to the UE <NUM>.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the eNB <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication may include means for determining at least one of the number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols. In one configuration, the means for determining at least one of the number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for determining at least one of the number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols may be the DM-RS scheduling component <NUM> or the processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' may include means for transmitting the at least one of the number of the one or more DM-RS symbols or the one or more locations within the subframe for the transmission of the one or more DM-RS symbols to a UE. In one configuration, the means for transmitting the at least one of the number of the one or more DM-RS symbols or the one or more locations within the subframe for the transmission of the one or more DM-RS symbols to a UE may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for transmitting the at least one of the number of the one or more DM-RS symbols or the one or more locations within the subframe for the transmission of the one or more DM-RS symbols to a UE may be the one or more antennas <NUM>, the transceiver <NUM>, the transmission component <NUM>, or the processor <NUM>.

In one configuration, the means for transmitting the at least one of the number or the locations of DM-RS symbols to the UE may be configured to send the at least one of the number or the locations of DM-RS symbols to the UE dynamically via PDCCH. In one configuration, the means for transmitting the at least one of the number or the locations of DM-RS symbols to the UE may be configured to send the at least one of the number or the locations of DM-RS symbols to the UE via RRC signaling.

In one configuration, the apparatus <NUM>/<NUM>' may include means for determining a resource allocation scheme for PC-RS. In one configuration, the means for determining a resource allocation scheme for PC-RS may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for determining a resource allocation scheme for PC-RS may be the PC-RS scheduling component <NUM> or the processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' may include means for transmitting the resource allocation scheme for the PC-RS to the UE. In one configuration, the means for transmitting the resource allocation scheme for the PC-RS to the UE may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for transmitting the resource allocation scheme for the PC-RS to the UE may be the one or more antennas <NUM>, the transceiver <NUM>, the transmission component <NUM>, or the processor <NUM>.

In one configuration, the means for transmitting the resource allocation scheme for the PC-RS to the UE may be configured to send the resource allocation scheme for the PC-RS to the UE dynamically via PDCCH. In one configuration, the means for transmitting the resource allocation scheme for the PC-RS to the UE may be configured to send the resource allocation scheme for the PC-RS to the UE via RRC signaling.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a UE (e.g., the UE <NUM>, <NUM>, <NUM>, <NUM>, or the apparatus <NUM>/<NUM>'). At <NUM>, the UE may receive at least one of the number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols from a base station. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

In one configuration, the number of the one or more DM-RS symbols may be one. In such a configuration, the one or more locations may include the first symbol of PDSCH or PUSCH. In one configuration, the number of the one or more DM-RS symbols may be two. In such a configuration, the one or more locations may include a first location at the beginning of PDSCH/PUSCH and a second location in the middle of PDSCH/PUSCH. The first location and the second location may be separated by at least one symbol. In one configuration, the one or more DM-RS symbols may be inserted in PDSCH/PUSCH for channel estimation.

In one configuration, the at least one of the number or the locations of DM-RS symbols may be dynamically received via PDCCH. In such a configuration, one or more bits may be reserved in DCI to identify the at least one of the number of the one or more DM-RS symbols or the one or more locations within the subframe for the transmission of the one or more DM-RS symbols. In one configuration, the at least one of the number or the locations of DM-RS symbols may be received via RRC signaling.

At <NUM>, the UE may decode the one or more DM-RS symbols from the subframe based on the at least one of the number or the one or more locations within the subframe. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

At <NUM>, the UE may optionally receive a resource allocation scheme for PC-RS with regard to the one or more DM-RS symbols. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>. In one configuration, PDCCH may be punctured to accommodate PC-RS.

In one configuration, the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols may be received dynamically via PDCCH. In such a configuration, one or more bits may be reserved in DCI to identify the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols. In one configuration, the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols may be received via RRC signaling.

At <NUM>, the UE may optionally decode the PC-RS from the subframe based on the resource allocation scheme for the PC-RS with regard to the one or more DM-RS symbols. In one configuration, the operations performed at <NUM> may be the operations described above with reference to <NUM> of <FIG>.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an exemplary apparatus <NUM>. The apparatus <NUM> may be a UE. The apparatus <NUM> may include a reception component <NUM> that receives downlink information from a base station <NUM>. The apparatus <NUM> may include a transmission component <NUM> that transmits uplink information to the base station <NUM>. The reception component <NUM> and the transmission component <NUM> may work together to coordinate communications of the apparatus <NUM>.

The apparatus <NUM> may include a DM-RS decoding component <NUM> that decodes DM-RS symbols from a subframe based on the at least one of the number or locations of DM-RS symbols received from the reception component <NUM>. In one configuration, the DM-RS decoding component <NUM> may perform operations described above with reference to <NUM> of <FIG>.

The apparatus <NUM> may optionally include a PC-RS decoding component <NUM> that decodes PC-RS from a subframe based on the resource allocation scheme for PC-RS received from the reception component <NUM>. In one configuration, the PC-RS decoding component <NUM> may perform operations described above with reference to <NUM> of <FIG>.

The apparatus <NUM> may include a data processing component <NUM> that processes data (e.g., decoding data from the subframe). In one configuration, the data processing component <NUM> may process data based on DM-RS symbols received from the DM-RS decoding component <NUM> and/or PC-RS received from the PC-RS decoding component <NUM>.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication may include means for receiving at least one of a number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols from a base station. In one configuration, the means for receiving at least one of a number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols from a base station may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for receiving at least one of a number of one or more DM-RS symbols or one or more locations within a subframe for transmission of the one or more DM-RS symbols from a base station may be the one or more antennas <NUM>, the transceiver <NUM>, the reception component <NUM>, or the processor <NUM>.

In one configuration, the means for receiving the at least one of the number or the locations of DM-RS symbols may be configured to receive the at least one of the number or the one or more locations dynamically via PDCCH. In one configuration, the means for receiving the at least one of the number or the locations of DM-RS symbols may be configured to receive the at least one of the number or the locations of DM-RS symbols via RRC signaling.

In one configuration, the apparatus <NUM>/<NUM>' may include means for decoding the one or more DM-RS symbols from the subframe based on the at least one of the number or the locations of DM-RS symbols. In one configuration, the means for decoding the one or more DM-RS symbols from the subframe based on the at least one of the number or the locations of DM-RS symbols may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for decoding the one or more DM-RS symbols from the subframe based on the at least one of the number or the locations of DM-RS symbols may be the DM-RS decoding component <NUM> or the processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' may include means for receiving a resource allocation scheme for a PC-RS. In one configuration, the means for receiving a resource allocation scheme for a PC-RS may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for receiving a resource allocation scheme for a PC-RS may be the one or more antennas <NUM>, the transceiver <NUM>, the reception component <NUM>, or the processor <NUM>.

In one configuration, the means for receiving the resource allocation scheme for the PC-RS may be configured to receive the resource allocation scheme for the PC-RS dynamically via PDCCH. In one configuration, the means for receiving the resource allocation scheme for the PC-RS may be configured to receive the resource allocation scheme for the PC-RS via RRC signaling.

In one configuration, the apparatus <NUM>/<NUM>' may include means for decoding the PC-RS from the subframe based on the resource allocation scheme for the PC-RS. In one configuration, the means for decoding the PC-RS from the subframe based on the resource allocation scheme for the PC-RS may perform operations described above with reference to <NUM> of <FIG>. In one configuration, the means for decoding the PC-RS from the subframe based on the resource allocation scheme for the PC-RS may be the PC-RS decoding component <NUM> or the processor <NUM>.

Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more. " The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Unless specifically stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof' include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. The words "module," "mechanism," "element," "device," and the like may not be a substitute for the word "means. " As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase "means for.

Claim 1:
A method of wireless communication of a base station (<NUM>), comprising:
determining at least one of i) a number of one or more demodulation reference signal, DM-RS, symbols (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) or ii) one or more locations within a subframe for transmission of the one or more DM-RS symbols (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
indicating (<NUM>), via one or more bits in downlink control information, DCI, or via RRC signaling, the at least one of i) the number of the one or more DM-RS symbols (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) or ii) the one or more locations within the subframe for the transmission of the one or more DM-RS symbols (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to a user equipment, UE (<NUM>);
determining a resource allocation scheme for a phase noise compensation reference signal, PC-RS, wherein the PC-RS is located in resource elements different from resource elements carrying the DM-RS; and
indicating the resource allocation scheme for the PC-RS to the UE (<NUM>).